AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: scorpion on 4 Mar 2009, 06:49 pm
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From time to time there has been some discussions of the JAMO dipoldesign R 909 (now there is also a R 907 along the same line): http://www.jamo.dk/Default.aspx?ID=5966&M=Shop&PID=17139&ProductID=17649. In particularl I remember one thread here from spring 2007 where MJK and myself were contributing: http://www.audiocircle.com/index.php?topic=41297.msg368661#msg368661 . I think this was the first time that MJK was hinting at what is now his famous passive OB-design with the Eminence Alpha 15s and the Fostex FE 103 E: http://www.audiocircle.com/index.php?topic=41297.msg368661#msg368661 , which he published in September the same year: http://www.quarter-wave.com/OBs/OB_Design.pdf . I went on designing the 'Volks-OB' put forward also inte automn 2007: http://www.audiocircle.com/index.php?topic=46951.0 .
However the thought of a 3-way passive OB-design along the JAMO lines never left my head, so here I now present one. I would like to see how far one could come with a JAMO like 3-way dipole speaker although on a budget. The choice should be made from units possibly performing at a high level but not taken from the most prestigous and expensive brands.
First I would like to introduce my partner 'Grizzla' to you. She pointed me to the anagramatical subject line by voicing her 'mjao' every day when something is at issue or just for company. She has contributed also with the letter 'G' in the name. Here you see her carefully examining some of the crossover components:
(http://www.audiocircle.com/image.php?id=18571)
The beginning was of course with simulation with MJK's Math Cad software. In this case with 2 Alpha 15s and the Monacor MS-100CHQ on a baffle with the same measures as the prototype presented below. Crossover were set with 12 dB/octave with LR characteristics at 200 Hz and 280 Hz. result was like this:
(http://www.audiocircle.com/image.php?id=18576)
This seemed promising enough to go further with a test baffle, which looks like this:
(http://www.audiocircle.com/image.php?id=18577)
It is an MDF baffle which measures 110/120 cm x 40 cm (44"/48" x 16"). Lowest Eminence Alpha15 is placed centered 22.5 cm (9") up from the bottom to give place for the small legs (shelf holders, two of the same at the back). The upper woofer is then placed as close as possible to the lower bass unit. Then the MS-100CHQ is placed 92.5 cms (37") up and 12.5 cm (5") in from the smallest side. Finally the tweeter is put on the baffle close to the midrange unit. The picture is of the left hand speaker , the right hand one is a mirror copy.
Units:
For bass produced by a narrow baffle I would consider the Eminenca Alpha15s as mandatory given the current market supply. They will give powerful, tight and transient true response to you. Those who describe the Alphas as sloppy and too high Qts speakers are simply wrong.
The midrange is supplied by the Monacor MS-100CHQ. My first encounter with this speaker was in a thread of German Audiodiskussion late 2005 titled (in translation) 'Fullranger bis 13 cms if you were free to choose'. Frank Kuhl of Monacor there put forward both the MS-100CHQ and the SP-130X/8 as possible alternatives. Later I bought a pair of both. The MS-100HQS were no fullrangers, so they were laying around til now. But the SP-130X/8 were put to good use in the 'Volks-OB'. For this design I however remembered the Monacor claims, so I decided to give it a try. I didn't regret. The link to Monacor is here: http://www.monacor.de/typo3/index.php?id=56&L=1&act=8&act_sub=23&artid=5258&spr=EN&typ=u . By some puzzeling thoughts these speakers are placed in the Monacor Carpower range. Given their response and build quality they should also be among the Hi-Fi units. MS-100CHQ is built in Germany by the same factory that also build the well known ETON speakers.
Among tweeters I chosed between Monacor units RBT-95 and DT-28N. RBT-95 is a magnetostat ribbon speaker ( http://www.monacor.de/typo3/index.php?id=75&L=1&act=8&act_sub=25&artid=6467&spr=EN&typ=u ) and DT-28N is an neodymium tweeter ( http://www.monacor.de/typo3/index.php?id=75&L=1&act=8&act_sub=25&artid=3573&spr=EN&typ=u ). My final desicion was in favour of the DT-28N which I thought presented the most pleasent sound. The square cut out you see in the baffle was for the RBT-95 units.
Crossover:
I had difficulties getting a balanced crossover between the bass and midrange using a 12 dB/octave filter.I was a bit puzzeld by that. So I decided along the KISS guidelines and tested 6 dB/octave crossover slopes. I stayed with them. All bits suddenly seem to fall in place, this is the filter:
(http://img368.imageshack.us/img368/2451/mjaofilter6.jpg)
which resulted in this (in my livingroom) frequency response:
(http://www.audiocircle.com/image.php?id=18578)
All in all you see here a +- 3.5 dB difference over all the frequency range.
Sound:
This by a margin is the best OB-speaker I have constructed so far. It outperforms the 'Volks-OB' in direct comparison. The B200s will not touch this mid-tweeter combo in performance. I have in fact stopped listening for faults in this speaker, just enjoying it. By the way it runs Lynn Olsen's speaker teaser: Mussorgsky's Picures at an Exhibition, orchestral version, with the Minneapolis Symphony Orchestra in full colours. Diana Krall's 'Live in Paris' comes over more 'live' than I ever heard it yet portraying the band beautifully ambient and my constant meter Manger's: 'Musik wir von einem anderen Stern' sounds like never before.
/Erling
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Erling,
your crossover looks EXTREMELY frugal for a 3-way. Getting such a response from three drivers and three filter components is almost unbelievable. I notice that you not even need to adjust for the efficiencies of the different drivers. It´s simply amazing. :thumb:
Rudolf :notworthy:
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Erling,
Very nice!
My four Alpha 15A's are sitting boxed in the basement. I have a pair of the Aurum Cantus ribbon tweeters in boxes behind the couch. I have a few Lowthers I could use for a mid range in a three way set-up also behind the couch, or I could buy a decent mid range driver. I am very tempted to start a three way OB design tonight based on your posting.
Aaaaaagggggggghhhhhhhhh, but I have something else I am working on that I promised myself I would finish this time.
I really like the idea of a three way passive OB, your design is motivating/distracting me.
Again, very nice!
Martin
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hi Scorpion - - that's a terrific report, test-build and measured result (-and Grizzla is beautiful) - I don't have MJK's simulator - sometimes with 1st order highpass there can be excursion peaking but apparently didn't happen in this case -- does your Monacor MS-100CHQ move much under big orchestral (or loud drum) passages? would larger midrange have worse result on vocals? which software other than MJK's sheets are good for helping with passive crossover? Best, Freddy
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Congras, especially when your current speakers out-performs the previous one, that is what DIY speakers is all about.
I always prefer a mid and tweeter combo to a full-ranger. Currently I am consider trying out the Eminence 8" with a ribbon tweeter similar what G. Pimm is using, he uses a simple x-over.The combo is very cost effective. A good quality mid-ranger is very hard to beat.
Cheers.
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greetings Erling, haven't been here for a goodwhile but looking at your post this morning piqued my interest. What is the overall efficiancy of the complete speaker.I must admit I am thinking of another solution to the b200 (it always seems like one of those relationships where you argue all the time but the sex is great and finally you feel like you can forgo some of the excitment for a more relaxed union). Must look into if anyone does monacar in Oz. Erling have you heard from our friend Nigel?I wonder how he is?
Thanks for sharing your project here, I can feel my tools in the shed getting nervous :D
peace and goodwill fergs
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What a simple rig - bravo! The right choice of drivers goes a long way. Looks like you chose well. :thumb:
At first I could not understand how you could use only 2mH on the bass, especially on a narrow baffle like that. But I did some calculating and found that the 2 Alphas in parallel should be be right at 100dB/2.83V before OB losses.. Your mid is at about 91dB/2.83V. That 9dB difference is just about right! Makes up for the OB losses. Guessing the bass to mid crossover is at about 400Hz. What do you think?
Not quite sure where the tweeter comes in, but you seem to be crossing it at 4KHz.
Nice work. Certainly a very simple, straightforward design.
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Hi Scorpion!
At least. Now you have done it.
Looks nice. Now I have to buy 2 more Alphas to make me a new Volks-OB. :D
Regards
Kludden
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Hi, Erling,
Congratulations!
You have done this very well especially with ARTA response confirmation.
I bought some 1,0 mH inductors for Alphas, also I am playing with some attenuation for Ciare
(just some kind of "Lpad" 7-8 Ohms parallel to Ciare)
Here is some pictures:
http://www.audiocircle.com/image.php?id=18599
Unfortunately I can not insert images right in the text?!
Janis
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hi Janis - is that CH250? - if so I like those - what's your crossover (if used) and attenuation pad?
(http://www.audiocircle.com/image.php?id=18599)
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Thank you all for the kind words !
Some things missing in the text and also asked for.
Frequency response is for the right hand speaker in the stereoseat 2.5 m from the speaker on midrange axis.
Sensititvity is a solid 95 dB at 1 m give or take some dBs over the audiorange as reflected in the frequency measurement. I adjusted the level to be 2 volts at 2 kHz over the midrange (about 1 watt) to perform sensitivity analysis. MDF is 19 mm thick (3/4").
Crossover components I have used here is from the Danish firm FreQuence: http://www.frequence-shop.dk/ . Capacitors are from their PCA range and coils are wire wound 1.2 mm adjusted with ferrit core. I measured the coils to 1.85 mH and capacitors values are 82 uF resp 4.7 uF. Prices are quite resonable and quality high. I suppose that quality components from Parts Express like ERSE coils and Dayton caps would give good results. A ferrit core coil with 1.2 - 1.4 mm wire with low internal resistanse should more than well cope with powers actual here and stay linear. For capacitors Obbligato from Diy-HiFI Supply (http://www.diyhifisupply.com/ ) are also favorites. Bass lowpass is calculated to 300 Hz and mid HP to 500 Hz approximately, effectively it will be like Pano's 400 Hz suggestion. But the Alphas will not fall of as fast as theoretically determined. Their performance is reflected in the measurement. They start falling at 300 but from 900 to 1600 they will stay level only about 12 dB below the midrange then they fall off rapidly. So they will contribute a bit more than presumed. The tweeters start at 5000 Hz. I experimented with some different cap values and settled for 4.7 uF giving the reported response. The mid falls off a bit lower than the published response curve would suggest at least the units I have. A good on-line crossover calculator is the Aj Design Crossover calculator here: http://www.ajdesigner.com/index.htm .
Rudolf, I guess I have been lucky in unit choice. In fact the Alphas have gained more than 3 dBs during run in. At first I had to take down the mid-tweeter combo.
I exercised the Alphas at 30 and 40 Hz in the beginning but only with my little Trend T-amp and that power was obviously not enough.
Martin, I think many look forward to a passive 3-way OB design by you. I will look into putting DT-28s also on the back for a true dipole design. This one follows the JAMO approach.
fergs, I haven't hear from Nigel for a long time. He said he would look inte new baffles for the B200s. I hope he is well.
freddyi, I have to rig up my SS NAD to stress the speakers more than the Trends can do. I'll come back with an answer to you. Regarding unit size I think all will depend on chassis characteristics. Larger units will probably start beaming a bit lower than the 4" unit. These speakers produce a reasonable Stereo over my 2.5 m listening sofa, but the stereoseat is absolutely best.
I estimate component cost for a pair of these speakers to ca 500 US$, excluding European VAT rate and transportation cost. One European supplier with competive pricing that will ship world wide is BMM audio & electronics: http://www.bmm-electronics.com/intro.asp .
/Erling
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hi Janis - is that CH250? - if so I like those - what's your crossover (if used) and attenuation pad?
Yes it is CH250, regarding crossover just 1,0 mH for Alpha and some attenuation for CH250.
Please let me know how you insert picture into text?
Regards,
Janis
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freddyi,
I owe you an answer with regard to midrange performance for the full symphony orchestra and heavy bassdrum. My Trend T-amp distorts when getting too high in SPL so I have tested with the NAD. 100-105 dB full symphony orchestra barely moves the cone. I tested with Beethoven 5th and there is no stressed sound.
Test with low kontrabass and bassdrum transients at the same SPL levels move the cone but I don't think over the 1.5 mm X-max and above all the delivery is effortless. The mid should also be able to take power according to specs. I tested with the Manger record, kontrabass with Renaud Garcia-Fons: Ghazali and drumpassages from the same record The O-zone Percussion Group: Jazz Variations. These selections spann a sound spectrum from the real low up to a bit high.
I am quite impressed, myself.
/Erling
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Alphas will not fall of as fast as theoretically determined. <snip> They start falling at 300 but from 900 to 1600 they will stay level only about 12 dB below the midrange then they fall off rapidly. So they will contribute a bit more than presumed.
That makes sense given their published FR and the fact of the rising response on OB. I've been wondering if the Alphas and the Monocors are not phase cancelling a bit thru that range. It might explain the broad midrange dip seen in your FR plot.
That should give the speaker a pleasent, laid back sound.
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Hi Erling ~
Your design is a triumph of understanding of how to bring together drivers in perfect "passive" concert together. It looks really great as well... form following function at its best!!! The thin tailored look of your Open Baffle's helps to make your design even more appealing.
Congratulations!!!!!
I will need time to study the information you were so kind to share with all of us... but I can see myself trying a version of your excellent design sometime in the future.
Thanks so much Erling, for sharing the wonderful results of your clear penetrating thinking with us.
Warmest Regards ~ Richard
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I am in on this too.
I am done with the CS2 clones and will put a new plate in the top section
for the two drivers.
(http://mysite.verizon.net/jkelly/ac/speaker_drivers_sm.jpg)
Jeff
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Hi Erling ~
I realize that listening to music with different speaker/amps/media is a terribly personal experience... and asking anyone to explain what they think they are hearing is fraught with dangers on all sides... but I wonder if you could go into the differences, in a bit more detail, to what you are hearing with your new 3-way Open Baffle driver arrangement, compared with your "Volks-OB" that uses the B200's.
For example... after reading with excitement how successfully you have integrated the 2 Alpha 15A's (hooked-together in parallel) with what appears to be the 3,1/2" Monacor MS-100CHQ... I listened a bit more intently to my own simple single Alpha 15A hooked in parallel to a single B200 and began to wonder how a much a smaller but dedicated midrange driver like the MS-100CHQ might sound in the magical area of the midrange compared to an 8" driver... especially given its relatively low sensitivity (90db).
What aroused my curiosity was remembering that I once had a 4" boxed full-range (?) single driver speaker that I played with for a few months... I found the sound less fleshed-out then a comparable 8" full-range driver and it seemed to me that the size of the driver may have played a part in this sense of a smaller musical space. On the other hand the smaller driver was faster than the 8" driver and there was more "detail" reproduced. I also realize that ones musical appetites may also play a part in the all-over equation.
Of course that experience has nothing to do with your present OB design... I am not extrapolating here... simply very interested if you could describe the differences you hear between your 3-way OB and your previous "Volks-OB"... especially your impressions of the mid-range.
Thanks in advance for any help you could give us here, Erling. Like many other Open Baffle enthusiasts on AC that have found your new 3-way design incredibly intriguing, I am hungering for more of your personal impressions.
Warmest Regards ~ Richard
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Scorpion,
I am having some trouble finding the MS-100CHQ listed
on the BMM site - I am awaiting a reply from them, but
are you able to find them on the site?
EDIT - thanks - Drivers are ordered.
Jeff
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Hi,
Try this link and choose convenient country....
http://www.monacor.de/typo3/index.php?id=99&L=1&act=7&act_sub=99&logged_in=
Peter
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thank you very much Scorpion
(http://img228.imageshack.us/img228/6608/linkpix.jpg)
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jkelly,
They are hidden away among Car audio loudspeaker units: http://www.bmm-electronics.com/Product.asp?Product_ID=7637 . They sell in pairs so the price is for two units.
Richard,
I am bringing up my B200s from the basement for a more thorough comparison. I'll come back with an answer to the best of my ability.
The 'Volks-OB's with Monacor SP-130 X/8 are more easy to judge about in direct comparison. They sound a bit 'harder' and when pressed the SP-130 X/8s also are a bit cracking/blaring. But that is at real high volume. The build quality of SP-130 X/8 is considerably below the MS-100CHQ. This is also reflected in the price.
/Erling
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Erling,
I like minimalistic approaches and your new OBs are amazing on this regard.
Are you running all passive right?
If so, could you measure the overall impedance of the loudspeakers that put to the amplifier?
Could you PM a bill of materials costs?
Now, two technical questions:
1) Mirror placement of midrange and tweeter: did you try centered placement? Plus/Cons of both approaches.
2) Sloped baffle top. I think I guess the reason of this. But how would it sound with a straight (shorter) baffle top?
Thanks in advance. Your post made my morning :)
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PS: Got an European dealer for Alphas?
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I was looking at the monacor mid-range and couldn't help but notice it looks a lot like the fe-103's. Just thought people who have built MJK's 2-way OB could possible give the 3-way passive a try by just ordering a pair of tweeters an inductor and a couple of cap's. What do you think? Anyone capable of running on simulation on it?
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Hi Erling ~
Thanks in advance for taking the time and effort to bring your B200's up from the basement for a careful comparative listening with your new 3-way Open Baffle "triumph".
I am excited to read what your thinking is about the differences and/or similarities between each Open Baffle speaker.
With Warmest Regards ~ Richard
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In my experiments with the Alphas I have always thought that setting the level of this driver relative to the others in the speaker was more important than the xover point, slope, etc.
Simply an amazing driver for the price up to 2 kHz or so.
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any impedance measurements? must one use a chip,class d, or SS amp or could a tube
amp be used? thanks for sharing your design.
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Richard, I have been through quite an interesting and timeconsuming comparison and investigation of Eminence Alphas + B200 with the MJAO.
I think I have some results that might interest B200 owners in general, so I'll summarize my findings in a new thread: 'Eminenca Alpha15 + B200 vs MJAO G 098'.
skite30, I think Fostex FE 103 E and Monacor MS-100CHQ are two completely different speakers. I wouldn't give any recommendations for MJK's Eminence Alpha15 - Fostex FE 103 E OB based on the looks of MS-100CHQ.
Telstar and mor2bz, Impedance to begin with. I have made measurement manually with this result: (selected frequencies) 40 Hz - 10.4 ohms, 80 - 5.3,
160 - 5.8, 320 - 5.8, 630 - 4.1, 1200 - 4.1, 2500 - 4.6, 5000 - 6.9, 10000 - 10.1 and 20000 Hz - 25.2 ohms. Minimum is 4.1 ohms in the 600 - 1200 range.
Any good amplifier should be able to cope with the load. I would label it a 4 ohm speaker.
Bill of material for one speaker (no VAT included and no transport):
Speakers from BMM Electronics (http://www.bmm-electronics.com/intro.asp)
1 MS100CHQ 56.75 US%body%nbsp; (But sell in pairs)
1 DT-28N 27.20 US$
From Premia Audio UK (http://www.premiaaudio.co.uk/epages/194597.sf/sec__U_ylihXS_/?ObjectPath=/Shops/194597/Products/EM1231). They seem to be
an interesting supplier for Europe. In US there would be several alternatives.
2 Eminence Alpha15 84 US$
Crossover:
From BMM Electronics (http://www.bmm-electronics.com/Product.asp?Product_ID=5450) ferritcore coil (In Europe, in US I would go for ERSE Supe Q 2.0 mH inductor at PE)
1 HQ56/1.8/160 19.4 US$
From DIY HiFi Supply Capacitors (http://www.diyhifisupply.com/?q=catalog/35/obbligatofilmoilcaps). They have very favourable transport cost for electronic components.
1 Obbligato 70 uF Film Oil Cap 29 US$
1 Obbligato 10 uF Film Oil Cap 11 US$ (To form the 80 uf capacitor in the crossover)
1 Obbligato 4.7uF Film Oil Cap 6.75 US$
I have some Dayton capacitors coming in, I can say something about them later. The Obbligatos are exellent sounding and more than worth the price.
The sloped baffle is more of a visual effect but an attempt to minimize baffle and diffraction effects. I don't think a square baffle and centered placement would bring any real audible difference.
And Telstar this is an all passive design as shown.
/Erling
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Telstar and mor2bz, Impedance to begin with. I have made measurement manually with this result: (selected frequencies) 40 Hz - 10.4 ohms, 80 - 5.3,
160 - 5.8, 320 - 5.8, 630 - 4.1, 1200 - 4.1, 2500 - 4.6, 5000 - 6.9, 10000 - 10.1 and 20000 Hz - 25.2 ohms. Minimum is 4.1 ohms in the 600 - 1200 range.
Any good amplifier should be able to cope with the load. I would label it a 4 ohm speaker.
I think that's too hard for my F3, even if the crossover is very light. Same should apply for 5-15W SET tubes.
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Hi Erling ~
I look forward with great interest to your new thread 'Eminenca Alpha15 + B200 vs MJAO G 098'.
Thanks for all of your hard work and sensitive, careful listening!!! It is very important work and it is very generous of you to share your insights with us!!
With Warmest Regards ~ Richard
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I think that's too hard for my F3, even if the crossover is very light. Same should apply for 5-15W SET tubes.
I got an idea: what if I use two midrange drivers? That should improve the impedance.
PS: which is the sensitivity?
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If you use the same midrange it is 4 ohm. So you would put them in series. Is that what you want to do? Bring it up to 8 ohms?
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So you would put them in series. Is that what you want to do? Bring it up to 8 ohms?
Yes. Would it work?
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Telstar, also the Alphas will border to 4 ohm in parallel.
But Monacor has three similar midrange drivers, beside the MS-100CHQ also MSH-116/4 and MSH-115.
'For your information the MSH-116/4 use the same Cone and voicecoil System but have a cheaper basket. The MSH-115 is very similar with a 8 Ohm voicecoil' is a direct quote from a mail conversation I had with Frank Kuhl of Monacor.
I simulated the MSH-115, http://www.bmm-electronics.com/Product.asp?Product_ID=5579 , and together with one Alpha15 on my baffle with the same good result as for MS-100CHQ just a few decibel less sensitivity around 90 dB/1 watt. For an 8 ohm system why not try MSH-115. This will also be cheaper with only one Alpha but you will have to work a bit on the crossover.
/Erling
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Telstar, also the Alphas will border to 4 ohm in parallel.
But Monacor has three similar midrange drivers, beside the MS-100CHQ also MSH-116/4 and MSH-115.
'For your information the MSH-116/4 use the same Cone and voicecoil System but have a cheaper basket. The MSH-115 is very similar with a 8 Ohm voicecoil' is a direct quote from a mail conversation I had with Frank Kuhl of Monacor.
I simulated the MSH-115, http://www.bmm-electronics.com/Product.asp?Product_ID=5579 , and together with one Alpha15 on my baffle with the same good result as for MS-100CHQ just a few decibel less sensitivity around 90 dB/1 watt. For an 8 ohm system why not try MSH-115. This will also be cheaper with only one Alpha but you will have to work a bit on the crossover.
/Erling
Hi Erling,
For the woofers I can go active, but for midrange and tweeter, I want high sensitivity (ideally 100dB) and high impedance (6+ ohm) to let my F3 shine.
The best thing of these Monacor drivers is price :)
Did you think of using two midranges? I was thinking of a MTM layout, the MSH-115 is indeed interesting (and even cheaper).
What do you think? How would you design the crossover in this case?
Thanks!
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Telstar,
MTM and MS-100CHQ serially connected also simulates promising. I would just try a 40 uF capacitor instead of the 80 uF to begin with. KISS !
Sensitivity should be about the same as for the MJAO. Just adjust placement a bit. Price was one factor which I found interesting but the best thing with these Monacors really is price/performance. :)
/Erling
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Hi Erling,
Just a few words to say that your continuing efforts in designing a great sounding yet simple OB speaker are fantastic, and will have folk scrambling to copy I'm sure. Well done. :thumb: As with Richard's design and some of MJK, it's the simplicity of an all passive and possible single amp solution that seems always to generate excitement. In this regard, your choice of 3 way, cheapish but 'good for OB' drivers well matched in SPL and a simple crossover design is ever so reminiscent of the KISS approach touted by Lukasz Fikus (aka Lampizator) for quite a while now, albeit with his passion for vintage AlNiCo rather than newer drivers.
http://www.lampizator.eu/SPEAKERS/PROJECTS/P17/Endorphine%20from%20Kingston%20Kitchen.html
With such simple and cheap-to-build designs like these, boxed speakers will have to become a thing of the past in a few years.
OK, that said, back to work in fine tuning mine.
cheers.. jeffac
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And Telstar this is an all passive design as shown.
/Erling
I'm thinking how would it look with 2x alphas (or 2x peerless, see this thread ) active, and with U baffles to go as low as 30hz.
And MTM with SH-115 midranges to keep 8ohm impedance. My goal is 96dB.
Attainable?
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Telstar,
Referring to mail.
jeffac,
Thank you very much ! It's appreciated.
/Erling
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why not dipole tweeter ? like bg neo3 , 36$
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I forgot, as my fist post, to salute all OB boys
I use supravox 215S bicone in OB ,guys, as this tecnology came from 1950 work very well with turntable !!!!
here an interesting cheap USA fullrange [url]http://www.diyaudio.com/forums/showthread.php?s=&threadid=139935&perpage=30&pagenumber=1[url]
Scorpion very nice work
Best Manu
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Welcome here nicoch,
As I said above I will put DT-28N on the back also to investigate dipole qualities fully. But remember that all fundamentals are reproduced by the midrange in dipole. That's a big difference from the Orion+ for instance which crosses to tweeter at 1400 Hz. I tested a magnetostat ribbon from Monacor also in this design but simply felt that I liked the dome better. Neo 3 is probably a very good altenative.
/Erling
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HI
rigth scorpion, I forgot that my bicone cannot have rear emission on the higth :oops:
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I forgot, as my fist post, to salute all OB boys
I use supravox 215S bicone in OB ,guys, as this tecnology came from 1950 work very well with turntable !!!!
I was considering these drivers for OB, as they seem very nice.
Can you describe your setup (maybe in a new thread)?
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nottingham analogue TT
koetsu black
erno borbely phono
erno borbely amp (fist 16w in A ,bias 1A)
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nottingham analogue TT
koetsu black
erno borbely phono
erno borbely amp (fist 16w in A ,bias 1A)
Oh, sorry I meant the speakers setup :)
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Hi Scorpion,
I am having some trouble getting the DT-28N tweeter.
Do you have any sources besides BMM?
Jeff
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Hi Jeff,
Try http://www.lautsprechershop.de/english/index_hifi.htm . They have an English translation and the Monacor in stock. But you should negotiate shipping cost with them. DT-28Ns are so light that they easily could be sent in a letter.
Or subsitute with Monacor DT-25N http://www.monacor.de/typo3/index.php?id=75&L=1&act=8&act_sub=25&artid=3574&spr=EN&typ=u (BMM has them) which is very similar and should do fine.
/Erling
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Here are the links from BMM
http://www.bmm-electronics.com/Product.asp?Product_ID=2700
http://www.bmm-electronics.com/Product.asp?Product_ID=7248
BTW, haven't said it yet, great job Scorpoin. Between you and Martin all passive OB's are things of the past. Great job guys!!!
Brad
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OK BMM replied - "We have to order this part from Monacor and delivery time is about 7 days"
So I can wait on that.
Thanks.
Jeff
-
Mids are in and tweeters arrive Monday.
Scorpion - do I want to add a low pass filter to the mid crossover?
Jeff
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While writing this I am listening to live Opera from the Metropolitan in a superb transmission.
jkelly,
This is the 64,000 dollar question. My MS-100CHQs fall quite a bit earlier than suggested by the published response curve from Monacor.
Also the DT-28N with 4.7 uF HP is responding a bit earlier than expected. My measurement of mid- and treble-units with their respective filter component is as follows (measurement corresponding to responsecurve in the first post):
(http://www.audiocircle.com/image.php?id=18863)
I tried some different values for HP capacitor but stayed with 4.7 uF which I thought provided the best integration with the midband.
If you can measure you will of course find out how units behave and adjust accordingly. If you have the feeling that mid and treble overlap too much then a good quality coil of 0.20 to .25 mH for a mid LP ought to solve this issue. I am glad you venture to try this project.
/Erling
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Nice job Erling
You have tricked me in to order all the components :D Not too much money for the lot either. I'm looking forward hearing it.
A question on the baffledesign: Is the height important? Could it be like 1m? Would also a more narrow baffle against the top be better for midrange performance?
Best
Bjørn
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Hi all,
my first post here. I recently tried an OB-design with the 15" Ciare together with Omnes Audio L8.
(http://s11b.directupload.net/images/090322/temp/n62wdn7h.jpg) (http://s11b.directupload.net/file/d/1741/n62wdn7h_jpg.htm)
(http://s10.directupload.net/images/090322/temp/3yt7axzo.jpg) (http://s10.directupload.net/file/d/1741/3yt7axzo_jpg.htm)
(http://s10.directupload.net/images/090322/temp/8mdmb4vw.jpg) (http://s10.directupload.net/file/d/1741/8mdmb4vw_jpg.htm)
Sound is dynamic, open, warm and yet clear. Very realistic.
I am about to replace the Ciare 15" by Alpha 15As. When playing loud, the huge Ciares are the first ones to reach its extention limits.
Till
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Hi Björn,
So you will try MJAO, that's interesting, I suppose you still have the Bastanis to compare. Would be fun to hear about.
Going down to 1 m should be alright, adjusting midrange height slightly and put tweeter just above. You could go with square baffle or like me 100/110 cm.
Mid and tweeter a bit offset or placed in the middle, I cannot see anything than very small differences in simulation. Since basses occupie 80 x 40 cm there will not be very much to play with up to 1 m but feel free to experiment. Something like 'fivestring's baffle with a flat top-section (in fact a bit important) just above the tweeter might look nice. But I don't think that any difference could be heard. :)
Hi Till,
Welcome, very nice baffles ! I have heard the Omnes L8 only on DIY Hi-Fi World in Gelsenkirchen and then in an aperiodic enclosure. They are very good I am certain. Perhaps more people should try it in OB. It appeared in the days when Ciare CH250 was the big hit and lived a bit in it's shadow. But I don't think L8 will need any frequency correction having a quite flat response like Monacor SP130X/8 which I have used. Can you do without a tweeter ?
/Erling
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Hi all,
my first post here. I recently tried an OB-design with the 15" Ciare together with Omnes Audio L8.
Till
Very nice, I like the light color. Let us know how it changes with the alphas.
-
Scorpion - what do you think are the power requirements for this setup?
Jeff
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Till,
Nice speakers. I like how the pin stripes make the baffles visually less obtrusive. Can I ask how you chamfered the back around the mid like that? Can't imagine that was done with a router.
Josh
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Thanks Erling
Excatly what do you mean by flat top-section?
Bjørn :)
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Jeff,
1 watt is enough and I think 20 undistorted watts in 4 ohm will provide a soundlevel that will satisfy most demands.
Björn,
Have a look at the pictures in the thread: http://www.audiocircle.com/index.php?topic=65818.0 . The flat section at the top is not there by mistake it helps minimizing diffraction. A rounded top would have been worse.
/Erling
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Thanks Erling. I see.
Bjørn :thumb:
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Hi Till, welcome to AC, Nice baffles, have done a few very similar, and in white as well. I have a pair of white ones in stock now, and I am thinking of bringing them home for a change from my veneered ones. Nice job :D
Mr C aa
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Thanks for your nice welcome.
Hi Erling, you are right, the L8 do not have a frequency correction at the moment. Let´s see how it will sound when the Alphas will replace the Ciares. These are run actively at present by two Hypex DS 2.0 modules. I plan to try an entirely passive modus then. There is a horntweeter-backup on the back side of the panel, smoothly cut off with 1.33 mF:
(http://s10b.directupload.net/images/090323/temp/empm4et2.jpg) (http://s10b.directupload.net/file/d/1742/empm4et2_jpg.htm)
(http://s11b.directupload.net/images/090323/temp/uqbkd7b7.jpg) (http://s11b.directupload.net/file/d/1742/uqbkd7b7_jpg.htm)
Hi dmiller, I will be happy to report after the exchange of the bass.
Hello Josh, the engraved stripes (by router) indeed "function" just as an optical support to slimline the overall shape. You asked about the flat back around the back of the midrange; yes it was done just by router. As there is no router allowing digging such a wide and flat shape with a diameter of 38 cm (15") and depth of about 3.5 cm (1.4"), I did it by starting with an outer circle and, while decreasing the diameter step by step, I went deeper and deeper, creating a structure like in an opencast mining field:
(http://s11b.directupload.net/images/090323/temp/pn9scczs.jpg) (http://s11b.directupload.net/file/d/1742/pn9scczs_jpg.htm)
(http://s10.directupload.net/images/090323/temp/haemx6ji.jpg) (http://s10.directupload.net/file/d/1742/haemx6ji_jpg.htm)
After that: sanding and sanding (you will know...)...
(http://s10.directupload.net/images/090323/temp/g4pllmub.jpg) (http://s10.directupload.net/file/d/1742/g4pllmub_jpg.htm)
The back of the panel after receiving it back laquered, before assembling the rest:
(http://s10b.directupload.net/images/090323/temp/kxj8uoue.jpg) (http://s10b.directupload.net/file/d/1742/kxj8uoue_jpg.htm)
Hi Mr. C., I like your vaneered ones, too! Very nice idea with the diagonal design of the "curtains".
Till
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The flat section at the top is not there by mistake it helps minimizing diffraction. A rounded top would have been worse.
Erling (and for that matter everyone that has been posting information about their projects here,) I've found it all very interesting and am contemplating putting together an OB along the lines of The Anagram at some point.
Would you be kind enough to explain to a relative simpleton why the above is so? Would a square or angled baffle be 'better' than an gently arched top then acoustically? I'm sure there's probably a very obvious reason but it's useful to understand it (mainly so I can explain it to the wife when she starts commenting on the appearance!)
While I'm here, could I ask you what the useful lower frequency range is? I'm guessing somewhere around 40 Hz?
Thanks,
Gary
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I'll try to illustrate with an example with the Edge program, that illustrates diffraction effects of the baffle. Edge is here: http://www.tolvan.com/edge/ .
First a baffle like the MJAO but with a rounded top and the midrange placed in the middle at the same height as in the MJAO.
(http://www.audiocircle.com/image.php?id=18922)
resulting in diffraction effects from the baffle like this:
(http://www.audiocircle.com/image.php?id=18921)
You can do guite a bit better by manipulating baffle shape and speaker placement. You will however always have some kind of dipole effect with a hump in response. But this rounded baffle top is not the best you can do.
It should also be pointed out that this is pure theory and real life measurement in a listening room can very well prove it wrong. :)
/Erling
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That is a pretty mind-mangling program! (I've been up working all night so perhaps it will make more sense after a sleep)
Any chance of a pic showing the cross-over or back of the baffle please?
-
You wouldn't like to see that at the moment. However things will change and I will have a presentable LS at our Swedish yearly Hi-Fi Forum DIY-show April 18th in Gothenburg, where I hope to make an impression. Then you will have the picture. I am among the few Swedes advocating OB but have plagued my fellows with the Ciare CH 250, the Volks-OB, the B200 and now the MJAO and quite a few are converting.
I also have taken some distortion measurement of the MJAO . These are just one meter closer to the speaker (right one) and mic is pointing to somwhere in the middle of the baffle a little above woofers. Frequency response is a bit different from the sweetspot measurments. Also German Klang & Ton in a rewiev of ARTA stated that distortion mesurements should be taken more near the loudspeaker.This is the picture, 95 dB avarage SPL:
(http://www.audiocircle.com/image.php?id=18926)
-40 dB is equal to 1% distortion - 50 dB is equal to .3% distortionm and -60 dB is .1 % distortion
/Erling
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Cool. Look forward to that, interesting this is.
-
Eventually I have received some Dayton Metallized Polypropylene 60 uF capacitors from PE and I have played around with the mid crossover for some days now.
The result is that the PCA capacitor has just been a try. It is not as good as either the Obbligatos or the Daytons. I have played both with 90 uF (Daytons + 30 uF Obligattos) and 130 uF (Daytons + 70 uF Obbligatos) and it is funny but the effect on crossover frequency has been quite low if I believe my measurements. But the midrange comes out with a new very pleasent authority - like this is the way things should sound. It would certainly be interesting to hear how other users find the Dayton caps. Tweeter is now crossed with a standard Mundorf M-cap 4.7 uF.
/Erling
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I do run the MJAO with 130 uF (60 uF Dayton + 70 uF Obbligato) now to the midrange. It is a bit on the low side for heavy bass, but the sound is the better. I should perhaps try to design a 12 dB crossover for MS-100CHQ to protect it from heavy low-bass. But it seems to cope very well so far. Stay tuned if interested.
/Erling
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Also 4.7 uF Obbligatos in place now for the treble, another not so small lift in overall performance. I went for our yearly DIY-meeting in Gothenburg with the MJAO. Overall I think people liked what they heard, but I was especially pleased by female response to the speaker, picking it out as one of the very best there, more than two witnesses. Women hear much more than we men do, usually. And we boys are competing more than we will acknowledge.
/Erling
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Hey Erling, just letting you know someone is listening. Keep up the good work and thanks for sharing.
Brad
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Rudolf was right, the crossover was too frugal. I have had a lot of comments from the Gothenburg DIY-show. Most were very favourable but a few insisted that the Alphas played too high in frequency interferring with the midrange. I went home and listend to the crossover. Using ARTA and Pink Noise signals this is easy. However I should have done this long before. But my computer where measurements are generated and the speakers are in different rooms, so I usually ran forward and back to watch measurements so this had slipped my attention. Conclusion is: Alphas do give out much more HF than desirable.
I have read some comment about, either here or at diyAudio, that trying to crossing Alphas looked more or less the same irrespective how you set crossover. I can vouch for this. I have both before and after making changes measurements thats looks more or less the same, and that's not really depending if you use 1st or 2nd order filters. They more or less produce the same result. That means that the Alphas are a tough beasts to tame passively.
I wanted to stay with 6 db slopes so this is my result:
(http://img368.imageshack.us/img368/2451/mjaofilter6.jpg)
The result is that MJAO G 098 is an even more detailed speaker now. Both the Zobel and the Parallel Notch contribute, you can't do without the other. The notch is calculated at 1500-1600 Hz. Getting rid of those HF-contributions generates an effect that is in fact a bit amazing, there is a kind of Blackness in the presentation that usually is associated with amplifier performance but an effect that I now can associate to the resolution and to 2nd- and 3rd-dimensional presentation.
The small story, you can't leave these changes out, then you will underperfom these good speakers. I hope you can see from the picture the chosen values. If not let's know. The Zobel is 3.9 ohm and 47 uF and the parallel notch 1mH and 10 uF.
/Erling
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Great, I have to order some more parts then :o
You also reduced C1 from 130uF to 100uF?
Good work Erling. Keep it up :thumb:
Bjørn :)
-
I still play with the 130 uF combo (I just happen to like the tonal quality of the Obbligato - Dayton combination), but I have tried values from 70 uF and upwards with very little if any difference. So 100 uF should work fine.
Yes, the extra parts will cost some money but they will be worth it ! :)
/Erling
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I forgot to mention, if you got a 6.8 uF cap at home it will do the same job as the 10 uF in the Parallel Notch. Both efficiently blocking the big 2 kHz Alpha hump to an enormous benefit for the speaker.
/Erling
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Scorpion,
Probably an obvious answer, but what about dynamics comparing using the Monacor's vs the B200. I have received the Monacors but havent opened them, possibly looking to trade them for a pair of the B200's. The Alphas can certainly respond with the dynamics, but can the little Monacors keep up?
Just to fyi presently I use a DDS waveguide and BMS 4552nd x-over at 1k, and have a driverack PA and dcx24/96 to choose from, but I think lowering the x-over point to a better midrange than using the Alphas to 1k may (hopefully),improve things.
thanks
-
scorpion,
How do you apply your Zobel to the Alpha 15"? do you measure the impedance first and the apply the calculated Zobel network? The Zobel network makes it easier for the amplifier to drive.
How does apply Zobel makes a different to the sound reproduction?
Cheers.
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Hi Erling,
Yeah, I feared that going 3-way would require more complexity in the XO, which was the main reason why I took a different route.
Your project still looks great and will stay in the affordable budget :)
And now it sounds better too ;)
-
nvrgdenuf,
If you want to match the BMS sensitivity the Monacor will fall short. I have tested with high bass/low mid high transient content and gone to 100-105 dB SPL with no problem. But that's probably the limit, the midrange will be too stressed going higher. There is a new Monacor unit, which already has attracted some interest in Germany I understand, the SP-8/150PRO: http://www.monacor.de/typo3/index.php?id=84&L=0&artid=7376&spr=DE&typ=full . This might be interesting to you. From my simulations it would be a perfect match for two Alphas on the 40 cm wide baffle.
ttan98 and Telstar,
Well, the Alphas are just 1-way but impedancewise evidently complex enough to deal with.
The Zobel is calculated from measured electrical resistance of the parallel Alphas and Eminence published Le figures. My LC-meter is of the simple sort measuring inductance at a given frequency, in my case 900 Hz, so this won't give you a good measurement but could be used for guidance. I have applied values obtained from a calculator which probably uses some rule-of-thumb formula.
The Zobel helps the crossover coil a bit but it is not effecient enough to get rid of all hissing content in crossover output. To effectively silence that the notch is introduced. Theoretically the Low-Pass should be effective from 300 Hz and now it also starts to sound like that. If you can, listen to your crossovers. Then you will much easier identify things that should not be there than what you can hear only by playing music. :oops:
/Erling
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Scorpion,
If the fq response is as smooth as the plot shows, what a fantastic driver. I dont know squat above driver construction, but when I look at different driver fq plots, there seems to be some serious peak or dip someplace. I will think about ordering a pair and get back to you if I get them.
andy
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The small story, you can't leave these changes out, then you will underperfom these good speakers. I hope you can see from the picture the chosen values. If not let's know. The Zobel is 3.9 ohm and 47 uF and the parallel notch 1mH and 10 uF.
/Erling
Hi, Erling,
just look at this simple parallel design:
8 Ohm (Alpha 15) parallel with 4 Ohm (Ciare CH250) and common Zobel= 4,2 Ohm+33 uF for both.
http://archive.http://www.audiocircle.com/index.php?action=gallerysearch&cat=0&pos=4 (http://archive.http://www.audiocircle.com/index.php?action=gallerysearch&cat=0&pos=4)
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Greetings Erling, this project looks more inviting every day but I have a question, what sort of load would the mjao present to a valve amp esp a 300b se. Or would this be inviting dissapointment?
cheers fergs
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Hey frergs, dont forget to drop by the Aussie forum :thumb:
Mr C aa
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Hey frergs, dont forget to drop by the Aussie Circle :thumb:
Mr C aa
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fergs,
I have been playing the MJAO with my Music Angel KT88 PP amp at 4 and 8 ohm output with no problems. Also in Gothenburg it played with one 6B4G SE 3 watt amp with great success. I think ouput transformer was specified to 8 ohm. However at the same meeting it played with another SE amp which I do not know the quality of but then the sound 'wobbled' if you know what I mean. I think it was a mismatch between output transformer and MJAO.
That's the tube story so far.
/Erling
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Erling:
Care to help some of us with your passive XO for a SINGLE Alpha?
TIA
-
Brassear,
I am a bit at loss hear, what to crossover about to, and why might I be of help ?
For what it is worth I think I will recommend MJK's effort to cross one Alpha15 with the Fostex 103E unit http://www.quarter-wave.com .
I have been doing research into this crossover and I think it will be doing just fine for the purpose designed. A single coil will let through to much in the 1 kHz - 2 kHz band.
/Erling
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Greetings Erling, I wonder if I can just run this by you, could I substitute the monacor midrange with the scanspeak http://www.scan-speak.dk/datasheet/pdf/15m_4531k00.pdf . As luck might have it I can get a pair of these for the same price as the monacors locally, and I imagine the quality of the scanseak would be higher. The graph looks very similar but I'm a nuff nuff when it comes to the specs.Ive passed this project past the better half and so the excitement levels are growing :D
peace and goodwill fergs
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fergs,
A simulation with the ScanSpeak unit:
(http://www.audiocircle.com/image.php?id=19629)
This should be fine. I have investigated 2nd order crossovers a bit more and would recommend 2nd order Linkwitz-Riley at around 250 hz which will take down the 2 kHz peak in the Alphas to a sufficient low level. 5 mH and 122 uF for the Alphas and 70 uF and 4.7 mH for the Revelator should be about right.
Let us here about the progress. :)
/Erling
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Greetings Erling, thankyou kindly for your advice. I'm curious is the recommendation for 2nd order L-R just for the scanspeak/alphas combo or have you been investigating them for the original MJAO as well, and will this have an effect when using valve amps?
cheers fergs
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With the MJAO 2nd order filter for the Alphas took down the level a bit too much to match with the Monacors so I preferred to stay with 6 dB slopes. Here it seems the Alphas could be taken down some dBs to match with the ScanSpeaks. Also with regard to my trouble with the simple crossover for MJAO I was curious to measure the 2nd order filter and it will perform brilliantly without notch or Zobel which is a comfort.
/Erling
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Hi Erling,
I don't know if it is just me, but I can't see any of you pictures you posted in this thread (including the final crossover). Could you please repost it ?
Thanks, Bratislav
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The Gallery is not in place yet so pictures all over the Cicrle are missing at the moment. It will come back I suppose and the pictures with it. I reposted the new version of the crossover in post #72 from another source. I think the text will be enough to understand the rest of the design.
/Erling
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Selling the Monacors used by Scorpion in the For Sale section. Unused and at a big loss.
-
I and my friend John finally got around to converting my CS2 clones to the Anagram model.
We took the horns out and made a circular plate for the mid and tweeter.
(http://mysite.verizon.net/jkelly/ac/sp2.jpg)
(http://mysite.verizon.net/jkelly/ac/sp5.jpg)
I used your updated crossover but have some rheostats inserted to play with levels.
I am running the mids about 1/2 volume. (edit: Now replaced with Obbligatos - no pots)
(http://mysite.verizon.net/jkelly/ac/sp3.jpg)
(http://mysite.verizon.net/jkelly/ac/sp4.jpg)
The Monacor speakers are very smooth. I like them.
The tweeter however seems very directional. Together they do
a great job.
I am playing with postioniing to lessen and tighten the bass.
I am starting to think I may want to try different bass drivers. I actually
like the sound of bass from the 18" Goldwood better than the 2 Eminence.
Any suggestions on a new pair of 15" 's ?
I only have about 40 hours on the mid and tweet and hope they
continue to improve and add more magic as they break-in.
On some songs the system is excellent. I am having better luck
with these than the CS2 clones.
Jeff
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I made CS2 clone as well, you see I add in a midrange like you and found the overall sound improves. Even better Emerald Physics found that too because CS2.3 now includes a midrange as well.
Cheers enjoy your speaker.
BTW you may like to consider Hawthorn 15" woofer as a replacement, if you do use 2 units per side instead of just 1 unit.
-
I am playing with postioniing to lessen and tighten the bass.
I am starting to think I may want to try different bass drivers. I actually
like the sound of bass from the 18" Goldwood better than the 2 Eminence.
Any suggestions on a new pair of 15" 's ?
Beyma.
-
The tweeter however seems very directional.
Maybe because the distance of tweeter and mid is too large (for my taste).
Regards, Micha
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Very nice built Jeff ! :) I do think that also the midrange will improve a bit when played in.
I usually sit in the sweetspot when listening but you are in fact right about the tweeter beaming. That is a function of the 'waveguide' build. In fact the effect is less pronounced if the DT-28 is placed on the baffle surface rather than sunked in. A bit contrary to what one would think. But all in all it is a very good tweeter for the price and delivering nice non-fatigueing sounds. I would agree with Micha that placing the tweeter more close to the midrange would allow for a bit better blending perhaps.
/Erling
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Erling,
I would like to lower the volume of the bass drivers by about 1/4.
Pulling one woofer is too much. Do you know how I can do that?
Jeff
(I edited this question)
-
In my measurement of today bass is some dB below mid and treble - on average, revised crossover, and always has been. It looks like this:
(http://www.audiocircle.com/image.php?id=19836)
This is the response in my livingroom. It might not be a good idea to put resistors in front of the Alphas which will increase Qts a bit and may be introduce a boom. If you know how many dBs you would like to adjust then an impedance neutral L-pad can be calculated.
Erling
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OK thanks - let me play with position a little bit.
Jeff
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Thanks Erling, I just realized how non-specific that question was. I am using a single Alpha with a Geddes 15 inch WG and a B&C DE250 compression driver. Geddes high pass xo and I ended up using MJKs 2nd order low pass for the Alpha at 900 Hz. I do not hear any of the problems that the Alpha exhibits full range or crossed over much higher. Thanks for reminding be of the quarter-wave site as my baffle is almost identical to MJKs.
Brassear,
I am a bit at loss hear, what to crossover about to, and why might I be of help ?
For what it is worth I think I will recommend MJK's effort to cross one Alpha15 with the Fostex 103E unit http://www.quarter-wave.com .
I have been doing research into this crossover and I think it will be doing just fine for the purpose designed. A single coil will let through to much in the 1 kHz - 2 kHz band.
/Erling
-
I have now taken the Erse caps out of the mid and tweet and put in the Obbligato's and bingo!!!
(guess it makes sense to follow the designer!)
The balance is perfect and the overall sound is warmer and much more pleasing.
I am only using the Obbligato 70 on the mid - do I need to raise that up?
Thanks Scorpion!
Jeff
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Jeff, I don't think it will make much difference to have a larger value. I have been playing with 70 uF Obbligato alone and it was fine. I liked the 60 uf Dayton to so I have been using the combo. But it makes sense to cross a little higher than I do. And I would say that the balance will be alright with no other alteration. Obbligatos are excellent value capacitors.
/Erling
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BTW, the 5 watt Clari-T from RWA is a really nice match to these speakers in my home.
EDIT:
I have just received a Virtue Two amp and really prefer this amp with the Anagram over the Clari-T.
Very nice synergy.
-
As a tribute to Scorpion i will build a copy of his MJAO in concrete.
(http://www.audiocircle.com/image.php?id=20267)
One baffel build
Regards
Per
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Hi Per,
Did a stone fall from my heart or am I stoned ?
You have at least heard the original at our Gothenburg DIY Show. I am impressed by your concrete abilities, it does look fabulous, hopefully the sound will match. :)
So far I would say that the simple 6 dB/octave crossover pays off even if I had to develop it a bit to get rid of the 2 kHz Alpha peak. People with very good hearing (like my wife) spotted the difference.
/Erling
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Looking to add the Monacor mid to my alpha 15 4ohm and Neo 3 PDR open baffled tweeter.
I am new to crossovers. Can anyone answer this for me?
There is no inductor before the Monacor midrange. How therefore is the treble cut-off?
-
The MJAO crossover is specifically calculated for the units involved and this application. The natural roll off of the mid is used. I suppose you could cross the MS-100CHQ round 3 kHz 6 dB/octave and meet the Neo3 there. A 0.27 - 0.3 mH air wound or even better copper foil coil should do the job.
/Erling
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Scorpion, thanks for the feedback.
-
P.S. Can anyone tell me the mounting hole to hole diameter? I know the driver measures 100mm but that is before the addition of the four corner holes. I am hoping they may match the mounting holes of the fr125s driver.
Thanks in advance.
-
My estimate says 109-110 mm for the diameter.
/Erling
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Hi all,
Ric Schultz challanged me for time alignment of the MJAO baffle see: http://www.audiocircle.com/index.php?topic=53821.100 and I think I will try.
But before that I have made a full effort to ensure that the original MAJO G 098 performed at its best. Here are the last crossover figures:
(http://img34.imageshack.us/img34/9350/mjaofinalfinalivvii8.jpg)
As you can see there are some fundamental changes.
1st Bass notch is totally reversed; now 0,2 100 uF instead of 1 mH 10 uF and that is because of new insight. Not much of these thinghs are discussed in regular textbooks much less so in articles. But this is the way it is lower mH and higer C gets the better results for the series notch.
Also I have changed the mid crossover. For instance I felt that the 1st Violins at full strenght was a bit wrong at full pitch so taking it down was the normal answer.
There is much more to be said but I will stop here. Please show !
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I will give the changes a try. What brand cap do you like for c4?
Jeff
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Jeff,
These changes will bring improvment. The notch assists the crossover and make for a fine gradual fall. This was a genuine fault of mine, but it appears that smaller coil value and greater cap value will give the better notch effect here. The mid LP seems to avoid some nasty noises high up in frequency which only occasionally could be heard and mostly on classical music. And altogether I don't think that you can do better with these units. Staying with 6 dB/octave crossover is I think exceptional and the sound is in fact very good.
For the units not in the signal path I think that quality is not of so great concern. The caps and coils in the signal path is like follows: L1 airwound 1 mm thread, C1 is Obligatto caps film oil and L2 is .27mH foil coil, C2 is Obligatto 4.7 Gold premium cap. The bass adjustment resistor is 3.9 MOX and 47 uF bipolar cap and L3 is 0.2 airwound coil and the 100 uF cap is again bipolar, nothing special which I think is good enough. Now for the estimates, first overall frequency response at sweet spot about 2.5 m distance for the right hand loudspeaker, indoor in my living room 4.5 x 7.5 m walls more than 1 m back and at side:
(http://img186.imageshack.us/img186/465/mjaorevisedii090904.jpg)
then the same estimate but now with 1/24th/octave resolution:
(http://img83.imageshack.us/img83/9282/mjaorevised090904.jpg)
and the finally a distortion estimate at 90 DB SPL for the same speaker:
(http://img4.imageshack.us/img4/9165/mjaodistortion090904.jpg)
This is the way it is and probably 'as good as it gets'
/Erling
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OK thanks Erling - I have the new parts on order and will provide feedback after
I install.
I have to say that I am extremely pleased with the sound of this system.
I would highly recommend it to anyone. Great clarity without being harsh.
Bass is strong when needed but not overpowering.
Beautiful tone, depth and all the OB magic.
I have them about 4 ft off the back wall and 2 feet in from the side walls.
The Virtue Two amp works great with these speakers. (what speakers don't!)
I have demo'd these to 2 people and they both came away talking
about never hearing a system that clear and that the artists were in the room.
So something right is happening!
Again thanks for all the design work.
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I know this isn't the spot, but if someone wants a set of these monacors ( both mid and tweeter) I have a new unused set for $100 shipped. They cost me $197.
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Hi!
I could just agree wit Jkelly. This speaker suonds amazing. Thanks Erling.
(http://www.audiocircle.com/image.php?id=21819)
My copy of MJAO made in concrete.
Regards
Per
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Hi im new into OB and have done the first testing with one side removed from my lastet DIY speaker, just addead a 12inch woofer, and so far im very pleased with the result.
The plan is to do a colne of MJAU and Jamo 907. I wonder what happens if i place the mid/hige combo at the "top coner" opposite to MJAO.
Regards Henrik
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This post/speaker is perfect (!) since I've suddenly gotten an urge to try and build a Jamo R909 "copy", although with not quite as high-ends speaker units to minimize cost a bit.
This project looks very cool and relatively low budget. Nice. :D
However, it's been a while since anyone posted anything (including scorpion himself). Was this speaker project abandoned, or could one still get help/support? :scratch:
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Hello all, my apologies for reviving this thread, however I would like to try something similar and am looking for advice for a starting point. I don't think the midrange drivers used in this project are available any more (and maybe not the tweeters) or I would just build this and go from there. So to the question: if you were starting this today which drivers would you suggest for midrange and tweeter? I would like to use Acoustic Elegance bass drivers and my intention would be to use a digital cross over between the bass and mid/tweeter. I would prefer to have a passive crossover from mid to tweeter to allow me to use my parallel single ended 2A3 amp to drive them. Many thanks in advance for your help.
David Whistance