MJAO G 098 - The Anagram - Crossover revision

jkelly · « **Reply #100 on:** 24 Jun 2009, 12:01 am »

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)

scorpion · « **Reply #101 on:** 24 Jun 2009, 08:36 am »

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:

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

jkelly · « **Reply #102 on:** 25 Jun 2009, 02:37 am »

OK thanks - let me play with position a little bit.

Jeff

BrassEar · « **Reply #103 on:** 26 Jun 2009, 12:17 am »

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.

Quote from: scorpion on 11 May 2009, 07:43 pm

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

jkelly · « **Reply #104 on:** 28 Jun 2009, 02:03 pm »

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

scorpion · « **Reply #105 on:** 28 Jun 2009, 10:47 pm »

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

jkelly · « **Reply #106 on:** 2 Jul 2009, 12:57 am »

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.

Kludden · « **Reply #107 on:** 9 Jul 2009, 09:56 am »

As a tribute to Scorpion i will build a copy of his MJAO in concrete.

One baffel build
Regards
Per

scorpion · « **Reply #108 on:** 9 Jul 2009, 06:52 pm »

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

SAC · « **Reply #109 on:** 13 Aug 2009, 11:53 pm »

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?

scorpion · « **Reply #110 on:** 14 Aug 2009, 10:16 pm »

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

SAC · « **Reply #111 on:** 16 Aug 2009, 01:11 pm »

Scorpion, thanks for the feedback.

SAC · « **Reply #112 on:** 16 Aug 2009, 01:17 pm »

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.

scorpion · « **Reply #113 on:** 16 Aug 2009, 06:25 pm »

My estimate says 109-110 mm for the diameter.

/Erling

scorpion · « **Reply #114 on:** 4 Sep 2009, 09:00 pm »

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:

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 !

jkelly · « **Reply #115 on:** 4 Sep 2009, 10:34 pm »

I will give the changes a try. What brand cap do you like for c4?

Jeff

scorpion · « **Reply #116 on:** 5 Sep 2009, 12:54 pm »

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:

then the same estimate but now with 1/24th/octave resolution:

and the finally a distortion estimate at 90 DB SPL for the same speaker:

This is the way it is and probably 'as good as it gets'

/Erling

jkelly · « **Reply #117 on:** 5 Sep 2009, 02:08 pm »

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.

nvrgdenuf · « **Reply #118 on:** 6 Sep 2009, 04:57 pm »

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.

Kludden · « **Reply #119 on:** 7 Sep 2009, 09:13 am »

Hi!
I could just agree wit Jkelly. This speaker suonds amazing. Thanks Erling.

My copy of MJAO made in concrete.
Regards
Per