B200 and Eminence Alpha-15A report ~

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ttan98

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Re: B200 and Eminence Alpha-15A report ~
« Reply #40 on: 21 Nov 2007, 11:53 pm »


How do you sort that out?  You're stating there are ideas that are true and applicable to one's specific application. Okay, I can grasp that.  But then for the benefit of others, how do you sort out the ideas that are true but not applicable to your specific situation vs. the ideas that are bogus?


John

[/quote]

As far as I am concern I will only put out ideas/tricks/facts that are technical correct like the mutitap transformer case, or suggestions/recommendations that I have direct experience with and found to be true and correct(I am not a politician). For my  opinions only I tend to say, an educated guess, my opinion, etc.

For the suggestions/recommendations/"facts"/ideas from others I have no control over with, you have to read extensively to sort out the facts from fiction and use your own judgement to determine what is right or wrong or suitability and use them accordingly. Sometimes you use your gut feel to determine what is correct/suitable and try them out. Sometimes you think it is correct/suitable may prove wrong/not suitable.

I tend to be more cautious than others..Hope this clear things out.

hope this helps.


jkelly

Re: B200 and Eminence Alpha-15A report ~
« Reply #41 on: 25 Nov 2007, 04:12 am »
I received my 4.7 mh coils and installed them today.
This is what I purchased:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=255-648

The results are fantastic.  The Alpha 15A integrated beautifully with the B200's.
Again, this is with the B200 wide open and just the coil on the Alpha 15A's.  I don't think
I have ever had this quality and strength of bass reproduction in my system.

I am using the  "Jeff Day" Walmart cables on the Alphas and some MIT T2's on the B200
which I will change out to a slightly brighter cable.  Those Jeff Day cables are not broken in
and a little sharp on the top but they are a unbelievable tuneful bass cable.

The net result is a fuller, stronger, powerful B200 sound.  I would never know I had 2 drivers
if I couldn't see the panels.  I have great depth and detail and now solid tuneful bass.  I didn't
have that in v1 with the 12MH coils I had around from a NHT 1259 system. 

So for ~$200, cutting 2 holes and Richards advice I have taken my OB's
to the next level.  I guess I now know why you guys have been talking up the 12" woofers
on the panels. 

Thanks (again) Richard!

In the "lab" I am using a Vinnie 3950 and a Jolida 102B.






-Richard-

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Re: B200 and Eminence Alpha-15A report ~
« Reply #42 on: 25 Nov 2007, 04:51 am »
Hi Jeff/JKelly ~

Ahhhhhhh... you have got it!!!!!!!!!!!!!!!!!!!!!

You and I are actually listening to the same speakers in essence... just wait... it really does get better.

Congratulations, Jeff... you must be in audio nirvana... and just in time for the holidays!!!!

I am actually convinced that the OB experience with our B200 and Alpha configuration takes a bit of time for the ear to adjust to... that incredibly deep level of saturation of layers of harmonic tone, the lightening-speed and transparency of the transients, the lush vocals that melt your heart into puddles of emotion, the scintillating detail that puts every nuance into your room as if it was recorded this very morning, the startling sense of immediacy that catches you off-guard... and yes... the beautifully fleshed-out bass that expands the foundation of the sonic musical language... that sense of wholeness, of completeness that gets across the intention of the musicians and singers and composers... and also the real spaces of the recording created by the subtle ambient reflections that flood your room as the music unfolds.

You saved yourself thousands... and the nightmare of ultimate disappointment... by your own creative efforts.

With this OB your amplifier choices and media source will reveal incredible differences to you.

Your audio life will never be the same.

Warmest Regards... and a marvelous holiday season to all! ~ Richard



scorpion

Re: B200 and Eminence Alpha-15A report ~
« Reply #43 on: 27 Nov 2007, 06:42 pm »
I have helped Richard to get photos of his baffle in this thread. Here are the pictures with Richard's comments.

'Here are a few pic's with comments below each pic that help to explain the structural elements of the baffles. I hope this helps



Note the curved base... also the Alpha-15's are attached on the back... more about this to follow. The B200's are set-in flush to the 3/4"
maple plywood.



Back shows the separate circular "ring" that the Alpha's are screwed onto... the screws for the ring are what you see from
the front as a sort of nautical "design" effect. Note the simple inductor sitting on the base... positive leads of speaker wire
hook up only... the negative leads tie to themselves (do not touch the inductor at all).



Note the very narrow "wings" that attach to the inside of the baffle and also attach to the shelve on the top
and the base below... Jim designed this for structural integrity... I might have preferred another design solution
but Jim went ahead on this without our chatting about it and I think it looks just fine and does not seem to effect
the sound adversely.



I stepped back on this shot... my main living space in this 1976 mobile
home is 20 feet wide by 26 feet deep... the OB's are on the right side
in the front of the mobile... the left side is our eating area... I took down
some walls when we first moved-in and made it into a loft style
large room.

Let me know what you think.

Warm Regards ~ Richard'

Well, I think these OBs both look and of course sound gorgeous !

/Erling

-Richard-

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Re: B200 and Eminence Alpha-15A report ~
« Reply #44 on: 5 Dec 2007, 04:58 am »
Thanks Erling for placing the images of my latest OB baffles into this thread... very very kind of you... and also thank you for the kind remarks about its aesthetics... and while I am at it, thanks again for recommending the Alpha-15's to me... the most significant development in my OB life since I purchased my pair of B200's three years ago... and that was thanks to the good doctor Dan Mason... who is currently helping earth quake victims in Lima, Peru.

I want to report a very significant performance leap with these baffles... today I stuck 2 CD cases underneath the middle of the front baffles... raising both baffles 1,1/2" (one double plastic case and one single plastic case)... the performance change has been spectacular!!!!!!!

Aiming the Alpha-15 up in the front and down in the back has created a very very noticable improvement in the bass performance... I am talking about something very significant here... powerful bass presence that now gives a much fuller gestalt to the music. Also the "beaming" issues I had with the Planet 10 phase plugs installed in the B200's has disappeared entirely. Aiming the B200's upward seems to have fixed that problem.

But more importantly the music now has much more immediacy... voices are more noticeably alive... visceral.

For those that have perpendicular baffles do yourself a favor and try tilting them back. I don't know what 1,1/2" translates to in terms of degree of tilt... perhaps those highly skilled engineers in our community can figure that one out. But the effect is extraordinary.

Happy Holidays Everyone!!!! Warmest Regards ~ Richard

« Last Edit: 5 Dec 2007, 07:00 am by -Richard- »

Dmason

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Re: B200 and Eminence Alpha-15A report ~
« Reply #45 on: 7 Dec 2007, 04:52 pm »
Richard

that is the cleanest looking OB rig I have ever seen. Essence of DarkStar. The oil of Aphrodite. And the dust of the Grand Wazoo....

Yes, this is the OB experience rolled into one fantastic chunk of woodworking art - statement, a collision of arts, a veritable "Faculty of Arts and Crafts" ...everything we have learned about the outer fringe of DIY audio has been spun into gold by the obviously highly talented Jim. A statement on the Dark Arts. The dark star with its Jovian satellite. Each sphere in orbit of the other.

Anyone interested in OB should read Martin King's latest paper. www.quarter-wave.com   about the most important thing here is that in considering bass drivers, and mains, ideally the mains be rated at least 6db less sensitive than the bass driver rating. I believe this is one reason why the Alpha and B200 get along so well... below 2KHz, according to my measurements, which gybe with Visaton measurements, is that the B200 is about 87db. I do not consider this a high efficiency driver, like the Fostex FE208, or Lowther, but the good news is that it makes it a dream driver to mate with larger diameter bass drivers. The way Richard has it set up is perfect. A coil is all you need, to low pass the bass driver. I find the mains never sounded the same, or as good when high passed. Run them full range as there seems to be some unmeasured, but clearly discernable difference, possibly psychoacoustic in nature, but the mains always sound best run full range. I have found that the equalizer that is part and parcel of iTunes has been the single best development for home audio, especially with open baffle. I shelve off the entire pass band, but add lots of db's in the lower register, and the 6 X 9 Kenwood single drivers will make plenty of bass, with very little IM distortion creeping into the midband, along the inner circumferences of the oval cone. They are good drivers, and respond well to contouring. I owe Vinnie for turning me onto iTunes. It has been a good thing. Hard disk drives are inexpensive. I brought two of them  with me.

Yes, I am currently in Santa Luz, Lima Peru working with the World Health Organization, in an area that has been all but forgotten by the Western World, long after its newsworthiness has passed, it media value, no longer of value. What you didnt hear after the quake's one day news cycle, was that 50,000 were basically left homeless, and all together, stumbling around in several square miles of destruction, mothers, children, peoples parent. People's kids. ...people, with a government, and economy that is not capable the infrastructure necessary to dig its people out of this one. There are people from all over the world here, all are infidels, citizens of countries Al Quaeda would rather be here. My next door neighbor is a retired Canadian telecom engineer, and he is heading up the restoration of the wires, lines, and all that stuff. He is an inpiration, and study in living well. I am doing primary healthcare in the afternoon, and attending in O.R. in the mornings, at most four days a week. Three days are mine, and just so you dont think all this Schweitzerian, the food, the people, the art, the music, and the SURF are all world class. Peru has easily some of the most consistently fantastic surf on the planet, I like to surf, and I live ten minutes from the Left Coast. Every day we have big tureens of seafood chowder, rich broth teeming with shrimp, lobster, scallops, strange and wonderous vegetables, all seasoned artfully... I have only shifted gears, adjusted the "horizontal hold" on things. The ten days I returned to SD was during, The Fires, so that was ...interesting. Go home for a visit and get sick on smoke. My stereo consists of a pair of Kenwood single driver car speakers, on open baffle, with a Clari-T amp! It sounds fantastic. I should add that Bruce, the engineer from Ottawa, is fascinated by the sound of the speakers on concrete flavored plywood, and even more interested in the sound coming from the little black box, and has borrowed the stereo to use in his own place. A portable, community stereo.
« Last Edit: 7 Dec 2007, 08:35 pm by Dmason »

miklorsmith

Re: B200 and Eminence Alpha-15A report ~
« Reply #46 on: 7 Dec 2007, 05:06 pm »
DM - represent!  You make us proud.

scorpion

Re: B200 and Eminence Alpha-15A report ~
« Reply #47 on: 7 Dec 2007, 10:26 pm »
Hi Dan,

Glad you took your time to read and answer. I certainly also like Richard's baffles. Clean and straightforward. You are right in that a single Alpha 15 might well serve the B200. But you are wrong in stating the sensitivity below 2 Khz. In fact below 900 Hz the sensitivity is below 90 dB and the main point is how to tame the rising response above this point. Some like it as it is others do not stand it, it is a very personal reaction.

I think Richard has a very good point in his backleaning the baffles. He will be more in line with B200 on axis response and he might be helped a bit more with floor reflections and reinforcement in the bass. In fact this is also the good truth with OB's there are a lot more alternatives available to tune baffle response than with enclosures.

You are dead right about MJK's paper. This is essential reading for anyone interested in OB response. You can learn a lot if you read it and also figure out what you are actually reading.

/Erling
« Last Edit: 8 Dec 2007, 12:49 pm by scorpion »

Dmason

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Re: B200 and Eminence Alpha-15A report ~
« Reply #48 on: 7 Dec 2007, 10:38 pm »
Erling,

I agree completely. And I agree with Martin's sensitivity matching conclusions. I also notice that the original Japanese drawings for what is now known as the Joe Esmilla design, all call for about a 7' slant back, presumably to point the driver upward, but also to take advantage of boundary gain. I know the difference Richard is hearing. Seems the backward slant is mandatory.

About rising response, I believe that as we now have free access to very useful 24 bit DEQ by way of iTunes, people into OB should endeavor to use it. Equalization seems necessary to me at all times, but especially with open baffle. The B200 has a much different tone to it when you shelve off the rising response; likewise, I used it to lift treble response on my 1960s Coral 12 inchers. With contouring, they produce as much treble as I require, and it is amazing how little musical information there really is, over 4KHz. The Corals easily do 8KHz, which should be plenty for anyone with ears over 40. They also do real bass. Very nice speakers.

Backward slant of baffle, and active equalization using USB audio seem mandatory to me.

scorpion

Re: B200 and Eminence Alpha-15A report ~
« Reply #49 on: 7 Dec 2007, 10:45 pm »
Dan,

You are really tossing up good numbers. You are very right about 4 K, voices for instance will be covered to the 3rd overtone in this range, but again you would not really miss the rest of the frequency spectrum. And I should add I agree completely about 24 bit digital EQ possibilities that now are available. This works wonders. See I read to fast !

All the best,
/Erling
« Last Edit: 7 Dec 2007, 11:01 pm by scorpion »

miklorsmith

Re: B200 and Eminence Alpha-15A report ~
« Reply #50 on: 7 Dec 2007, 10:51 pm »
The Inguz Squeezebox plugin has a very handy semi-parametric EQ that would be great for tweaking this type of response - no microphones or measurement needed.  A ratshack meter and test tones might be helpful to target trouble areas though.

fergs1

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Re: B200 and Eminence Alpha-15A report ~
« Reply #51 on: 9 Dec 2007, 12:01 pm »
Greetings Fellas, have just found this thread although I've been aware of mjk's article for a while, and I'm finding the prospect of trying my b200's with the alphas exciting. I have lived with my b200 in open baffle for about 1 1/2 years and have been very pleased with the result running in conjunction with a sub but lately Ive wanted to simplfy my rig by getting rid of the bi amping and run them off a single 300b amp as well as go totally ob as the sub was a br, and Ive heard horn and ob bass and br just does not compare. So I need some advice.If I were to run the b200 and alpha together I realize that the coil goes inline with the pos lead to the alpha but how does it conect to the b200, and what do I do if I want to bring down the volume of the b200 wrt the alpha(important note, all advice must be rendered in such a way as to make sence to a 6yr old as I know so little about series parralel blah blah :?  Oh and what will be the final ohm of the ob so I know where to stick it into the back of the amp? The goodnews is that the woodworking side is a piece of piss as Ive already built three pairs of blh and these obs but unfortunately the wiring always stumps me.Hope to hear from you gentlmen                   peace and goodwill fergs

-Richard-

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Re: B200 and Eminence Alpha-15A report ~
« Reply #52 on: 9 Dec 2007, 09:02 pm »
Hi Dan ~

It is wonderful to read your energized and colorful prose once again. A marvelous infusion of fresh insights and fresh air in the often labored number-numbed world of audio. Of course we all have you to thank for starting the Dark Star thread several hundreds of posts ago, which has created this revolution in our thinking... and listening.

Jim McCarthy came over yesterday and was listening to some cuts he recorded of his son and his sons girlfriend singing Christmas songs, karaoke style... and we also listened to quit a few CD's. Jim is a composer, recording engineer, a musician (he plays in a band), a designer and a cabinet maker... he designed and built the OB baffles that Erling was kind enough to place into this thread for me. So he was actually hearing them for the first time. He wanted to let me break the new Alpha drivers in before a really good listen.

Jim is hard to please... he hears every anomaly in every recording and every speaker system... all those years of engineering recordings... which he still does... has left him with this highly critical ear.

Jim was quite taken back by what he heard. "I was wondering when you where going to finally get these OB's to sound really good... these sound fantastic... I am hearing things I never hear before on these CD's..." He was impressed to say the least.

I looked into your thoughts about ITunes having a built-in EQ Equalizer, Dan... It's fantastic!!!!!! You can learn a great deal about how an equalizer actually affects the sound with this nifty little tool. I am seriously considering buying a portable mac now and use it as my "CD player"... perhaps with a sound card for better fidelity. I will look into it very soon. Nice suggestion!!!!!

I hope you can pay a visit to Ojai when you return from Lima... I would love to hear your thoughts on these OB's and hear what your rig sounds like as well. Do take care Dan and happy holidays.

Warmest Regards ~ Richard


« Last Edit: 9 Dec 2007, 10:17 pm by -Richard- »

-Richard-

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Re: B200 and Eminence Alpha-15A report ~
« Reply #53 on: 9 Dec 2007, 10:10 pm »
Hi fergs ~

I will gladly share what little I know... but there are far more sophisticated minds contributing on this thread that understand the connectivity issues far better than l do.

I have speaker cable going from my amp directly to the B200's. From the B200's there is a short speaker cable that goes to the Alpha-15's... right now I have the exposed wire ends of the short speaker cables, going to the Alpha, wound around the exposed speaker cable going to the B200's at the + and - tabs. Each of the positive leads of that short piece of speaker cable wind around one of the 2 prongs of the inductor I am using: a simple wound iron core coil: Jantzen 3.9mH 14 AWG C-Coil Toroidal Inductor: 4.7 mH:(millihenry: a unit of inductance equal to one thousandth of a henry). The "negative" leads do not touch the inductor but go straight from the B200's to the Alpha's, exactly as you suggested.

I am driving both speakers with a Korneff 45 SET all tube amplifier: approximately 2.5 watts according to Jeff... with a preamp that has 2 different circuits to choose from... the all tube Peppard Magic 5... highly modified by Lloyd, for me, that has a gain of 20 db... those 2.5 watts are enough to blow Deb and I out of our house!!!!!

The integration of the B200's is seamless... quite magical. But if you want to be able to drive the Alpha's independently of the B200's you will need a separate amp... a plate amp with volume controls has been suggested by Dan Mason... or some device that boosts the volume of the signal coming from your amp before it reaches the Alpha's... such booster box's do exist.

But if you start to "adjust" the Alpha's to play louder (more gain) than the B200's... the seamless integration may be compromised. I ran the Alpha's independently at first with another tube amp that had tone controls before finally settling on using the Korneff to drive both the Alpha's and B200's in parallel. The SEP could go a bit lower... marginally... but there was definitely a trade-off in all-over integration... perhaps another kind of amp might have had better results. Still... the bass I am hearing is very effective. Jim was quite impressed... and that is saying a great deal!!!

My advice? Try the B200's and Alpha-15's without biamping first... and get used to the sound before making any purchasing decisions.

Now let's wait to read how the more knowledgeable AC members answere your question.

Warm Regards ~ Richard

Michael V

Re: B200 and Eminence Alpha-15A report ~
« Reply #54 on: 10 Dec 2007, 03:42 pm »
Fergs,

There's nothing expert about my opinions, but I can vouch that this setup works very well.  B200 run fullrange with a coil in series with the woofer (mine is from a Hawthorne SI, which is very similar to Richard's Alpha) results in a very integrated and full range sound, without any crossover colorations whatsoever from 250hz up.  I don't see any reason to attenuate the B200 because - frankly - it doesn't seem to need any.  A resistor would do the job, though.

Which output terminals you use would depend on a couple things, but I think the best advice is to try the 8 and 4 (if you have one) taps.  This determines what load is seen by the output tube (hopefully you use tubes), and this loading affects power and distortion of your power amp.

The impedance of these drivers in unison would dip in the crossover region, but is no problem for SET amps.  I've just completed a SE2A3 amp (conventional design, only 3.5-4W), and it has more than enough power and drive for this speaker setup. 

Somebody please correct me if I'm wrong, but wouldn't these drivers in parallel would have less of an impedance rise in the LF, and therefore easier to drive.  Can somebody please verify?

Anyway, I encourage you to try this.  It's amazing what flea-powered tube amps and OB can produce.

Thanks and best regards
Mike

Dmason

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Re: B200 and Eminence Alpha-15A report ~
« Reply #55 on: 10 Dec 2007, 06:33 pm »
Mike

Regardless of how you chain the drivers, or not, the rising response is far greater than what would in my mind be attenuated by Z @ >6KHz. My measurements looked alot like Visatons. This is what Dave Dlugos' phase plugs are all about. Otherwise, again new thinking is in order here, and now we have FREE 24 bit digital equalization courtesy of Steve Jobs.

iTunes DEQ

At only one octave intervals, I first thought this feature was abit hokey, until I started playing around with the canned presets, which CLEARLY are well thought out and are ALL highly useable. I found for example a way of playing Jethro Tull's "Thick as a Brick," and this album is an example, a notorious album for fabulous writing and musicianship, and really, reeellly awful production, and iTunes saves it, for the first time.

WHat I have been doing is starting with around a 4db shelve from 0db and go from there. Note that they included a GAIN setting on the "pre amp" which now becomes highly useable, and gives you a free 4+db EQ headroom also for free. I come to home audio from Pro Audio, my first "real" summer job was as an all round gopher for Clair Brothers, and was assigned to the 1978 summer US/Canada tour with a little band from England known as "Yes."  You learn things with a gig like that. One thing I learned was that active EQ was as essential to getting the most out of the room you have to work with, with the stuff you have to make music. Amplified acts would all sound uniformly like shit were it not for active EQ on several levels, from instrument mixing, to monitor mixing, to Front of House mixing, it is all EQd, and with OB, it becomes even more essential to my thinking, and home audio is definitely an amplified act.... and if using the B200, more important, but with the Coral 12s it is like alchemical reaction, and brings the actual tone of the Alnico magnets right up front and center. So I urge you to download iTunes and try it.

Michael V

Re: B200 and Eminence Alpha-15A report ~
« Reply #56 on: 11 Dec 2007, 06:52 pm »
Dmason,

Thanks for your post, but I'm not sure I follow.  My comment was about the low frequency end of the FRP, not the highs.  When the Visaton and Alpha in parallel, wouldn't the resultant impedance be flatter around 70-40hz than with either driver alone?

It seems counter-intuitive [to me] that two drivers together would be a flatter load...

centerfield24

  • Jr. Member
  • Posts: 4
Re: B200 and Eminence Alpha-15A report ~
« Reply #57 on: 27 Jan 2008, 04:01 pm »
Greetings, hoping to get some answers about this project. This is my first attempt at speaker building and the the knowledge of all on the board is greatly appreciated.First off ,full disclosure I liked Richards speakers very much and have built something very similar.A question about the wiring of the inductor still remains.I have wired the feed from the amp to the B200 speakers. I then ran a wire from the + terminal of the B200 to one side of the inductor,the other side of the inductor has a wire that goes to the + terminal of the Alpha 15A.I then ran a wire from the - terminal of the B200 to the - terminal of the Alpha 15A. Is this correct?
My next question is about Tube Amps, I am looking for some recommendations having never owned one.
I would consider buying used to keep the price down. Also are their any solid state amps that are being used or some that would be recommended .

                                                 Thanks To All
                                                  Bill

jkelly

Re: B200 and Eminence Alpha-15A report ~
« Reply #58 on: 27 Jan 2008, 06:10 pm »
Yes - you have it wired correctly.

I am using this same system with a affordable modified Jolida 102b (EL84) and
really enjoy it.  I have purchased NOS tubes which improve the amp dramatically.

Jeff


-Richard-

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Re: B200 and Eminence Alpha-15A report ~
« Reply #59 on: 27 Jan 2008, 09:23 pm »
Hi Centerfield24 ~

I have just received Vinnie Rossi's new Signature 70.2 monoblock amplifier... it uses the Tripath chip which is a digital/SS circuit... I have it combined with Lloyd Peppard Magic 5 SE tube Preamp. I intend to write a full report of my experience with this combination within the next 2 weeks here in the Open Baffle forum. However, I can say that nothing... nothing I have ever heard sounds like this combination... it is thrilling, utterly amazing!!!!!! and brings my OB's to life in ways I did not think possible. It raises the potential of my OB's to a level of resolution that has Deborah and I in a constant state of shock!!!!! Check out Vinnie's website Red Wine Audio:

http://www.redwineaudio.com/Products.html

Vinnie has a manufacturers forum on AC.

Expect a full in-depth report very soon.

Hi jkelly ~

I have heard great things about the modified EL 84 tubed Jolida... Dr. Steven Rayle who contributes to AC loves his... he is planning on sending me his modded Jolida in a few weeks so I should have a chance to hear what it can do for my OB's.

Warm Regards ~ Richard