DIY Emerald Physics CS2 Clones

BrassEar · « **Reply #80 on:** 8 Dec 2008, 08:17 pm »

I am not so much concerned about the low end extension of the Alphas when they sound this good down to around 40 Hz or so. These have the open, magical sound of Magnepan bass without the low efficiency and limited headroom. The best of both worlds really.

I would roll the Alpha off at some point though. Although it sounds very good full range, just play a solo piano recording and you can hear what almost sounds like ringing or blurring of the piano tones. I don't think it is room related. When I threw a .51 choke in series with my two Alphas, they now sound slightly rolled off but still magical.

I almost think I stumbled on a discovery here, mating almost full range alphas with a waveguide loaded compression driver - all using simple first order passive xovers! I honestly have never heard better sound.

doak · « **Reply #81 on:** 9 Dec 2008, 01:35 am »

Quote from: BrassEar on 8 Dec 2008, 08:17 pm

I am not so much concerned about the low end extension of the Alphas when they sound this good down to around 40 Hz or so. These have the open, magical sound of Magnepan bass without the low efficiency and limited headroom. The best of both worlds really.

I would roll the Alpha off at some point though. Although it sounds very good full range, just play a solo piano recording and you can hear what almost sounds like ringing or blurring of the piano tones. I don't think it is room related. When I threw a .51 choke in series with my two Alphas, they now sound slightly rolled off but still magical.

I almost think I stumbled on a discovery here, mating almost full range alphas with a waveguide loaded compression driver - all using simple first order passive xovers! I honestly have never heard better sound.

Very interesting indeed. Thanks for posting your progress.

IMO the digital crossover of the EP CS2 is not only what "makes them work" but is also their "Achilles heel". Spending several hundred dollars or more to upgrade it doesn't make much sense to me ---- "going analog" does though.

Best of Luck!

BrassEar · « **Reply #82 on:** 9 Dec 2008, 05:19 am »

Quote from: doak on 9 Dec 2008, 01:35 am

IMO the digital crossover of the EP CS2 is not only what "makes them work" but is also their "Achilles heel". Spending several hundred dollars or more to upgrade it doesn't make much sense to me ---- "going analog" does though.

I think you are exactly right about the Behringer and the CS2.

I guess these are no longer EP CS2 clones. They are more like an Earl Geddes/AudioKenesis design with OB bass. I am hooked on waveguides/compression drivers + OB bass.

scorpion · « **Reply #83 on:** 9 Dec 2008, 07:25 am »

You are certainly right here. The Alphas manage bass quite on their own without any EQ and they will play down into the 30'ies without any help.
I have DE250 coming after Christmas and the Dayton waveguide. It will be interesting to test together with my 4 Alphas. But what this fullrange wave also is opening up is a pairing of the Alphas and for instance Neo3PDR directly at about 2 kHz, like GR Research's OBs, lots of interesting options. .51 will begin rolling off at about 1200 Hz so it should be open for a lot of crossings.

/Erling

doak · « **Reply #84 on:** 9 Dec 2008, 04:39 pm »

Quote from: BrassEar on 9 Dec 2008, 05:19 am

I think you are exactly right about the Behringer and the CS2.

I guess these are no longer EP CS2 clones. They are more like an Earl Geddes/AudioKenesis design with OB bass. I am hooked on waveguides/compression drivers + OB bass.

Well, you're in VERY good company there!

BrassEar · « **Reply #85 on:** 9 Dec 2008, 05:43 pm »

Quote from: scorpion on 9 Dec 2008, 07:25 am

I have DE250 coming after Christmas and the Dayton waveguide. It will be interesting to test together with my 4 Alphas. But what this fullrange wave also is opening up is a pairing of the Alphas and for instance Neo3PDR directly at about 2 kHz, like GR Research's OBs, lots of interesting options. .51 will begin rolling off at about 1200 Hz so it should be open for a lot of crossings.

The DE250 in the DDS waveguide presents the best mids/highs I have ever heard. I have owned Quads, Maggies with ribbons, Vandersteens, NHTs, KEFs, Martin Logan CLS, etc. and nothing comes close. There is zero thermal compression going on and this is something you just have to hear to appreciate.

I agree, using the Alphas up to 1K or so opens up a world of options.

scorpion · « **Reply #86 on:** 10 Dec 2008, 09:33 am »

BrassEar,

One question, how do you attach the foam plug to the waveguide ?

/Erling

Victor · « **Reply #87 on:** 10 Dec 2008, 02:36 pm »

Last weekend I started with my CS2 clone project. I have the Alpha 15’s, the Dayton waveguide and the Selenium DT220i
I have a DCX 2496 and some amps: a T amp, a Sansui AU222, a Behringer EP 2500 and a Music Angel KT88

Before I started putting the speakers on a baffle, I just laid them on a old matras and let them play for a few days. I used the Alpha without any coil, just full range. For the tweeter I used a 2 uF capacitor. It sounded very promising, extremely fast and open.

So, I expected a lot form the baffles. First I have tried the above mentioned passive version with just the vintage Sansui AU 222. It sounded o.k. but not that great, it was rather shouty and peaky. The main problem is of course the sensitivity mismatch of the units. I tried to get a more balanced sound by using a vintage Technics parametric equaliser. The sound improved a lot.

Then I tried the active approach. The DXC 2496 was used with all sorts of XO points and shelves. I used the AU 222 for the Alpha’s and a T amp for the tweeters. It became clear that the Alpha’s do have a serious problem with resolution in the midrange. For some of us it may be acceptable, but I am not happy with it. The CS 2 use 48db at 1000hz. Crossing it at a higher frequency degraded the resolution.

I played with it for a whole afternoon, it sounded impressive but I was not satisfied with it. However I think I have to improve the rigidness and damping of the baffles before I can call my speakers a serious CS 2 clone.

I will also try another tweeter. I have a pair of Philips RSQ8P’s and am interested to see if it’s possible to make an (active) match with the Alpha’s.

BrassEar · « **Reply #88 on:** 10 Dec 2008, 05:44 pm »

Quote from: scorpion on 10 Dec 2008, 09:33 am

One question, how do you attach the foam plug to the waveguide ?

Erling:

Just a light touch of 3M adhesive spray on the inside of the foam. Shove it in the WG and hold for 30 seconds. Worked perfectly. In hindsight, I probably should have spent more time sanding the foam to perfectly fill the shape of the WG. I may re-do this down the road. The foam is one of those "tweaks" that is a dramatic improvement and I am not one for tweaks in general.

Please report back here with your thoughts.

BrassEar · « **Reply #89 on:** 10 Dec 2008, 05:50 pm »

Quote from: Victor on 10 Dec 2008, 02:36 pm

It became clear that the Alpha’s do have a serious problem with resolution in the midrange. For some of us it may be acceptable, but I am not happy with it. The CS 2 use 48db at 1000hz. Crossing it at a higher frequency degraded the resolution.

I am currently trying to zero in on where to low pass the Alpha. Right now I am at first order around 1200 Hz. It's a trade off in that full range they sound more "live" but you do lose resolution in the midrange and a slight honkiness when run full range.

I have a friend who is going down a similar road with Alphas/PE WG/BMS drivers and crossing over passively and then using an analog graphic EQ to smooth things out. I will try to get him to post here.

gainphile2 · « **Reply #90 on:** 25 Dec 2008, 11:53 am »

The honkiness when run full-range is due to that 2kHz peak. I did measurement and level it using notch filter f=1.8kHz, Q=5.4, depth= -8db and then it sounds fine. There is also a dipole peak at 400Hz.

My problem is I dont have a proper compression driver yet (expensive with current aus rate exchange) so a typical 1" dome tweeter is used and is quite strained. But from around 30Hz to 3kHz it's fine. I think a completely analog CS2 clone is possible albeit differences. If lucky perhaps can utilise only one amp.

I was also not happy with the overall polar response with only 1 tweeter firing forward and added another one firing from the back out-of phase. It is now more coherent and "correct". Not sure how I would implement this when the CD and waveguide is on hand.

Lazz · « **Reply #91 on:** 26 Dec 2008, 01:32 am »

BrassEar, you say {I honestly have never heard better sound}. Can you tell me what speakers you have heard and are comparing them to as I'm trying to get an idea of ob sound and performance.Thx Lazz.

BrassEar · « **Reply #92 on:** 26 Dec 2008, 05:59 am »

Lazz - I have owned various Magnepans, Martin Logans, Vandersteens, NHT, Quads, B&W, etc. I never have liked cones and I always thought horns sounded terrible. Waveguides, compression drivers, and OB bass has changed everything for me. Now, multi subs are completing my new world order of audio.

For these reasons I think people like Earl Geddes, Duke of AudioKenesis, and Clayton of Emerald Physics are at the cutting edge of audio and the commercial mags and reviewers are clueless.

David Weil · « **Reply #93 on:** 26 Dec 2008, 10:18 pm »

Clueless? Or writing for a living in favor of the companies who pay the ads in their magazines?

BrassEar · « **Reply #94 on:** 26 Dec 2008, 11:41 pm »

Quote from: David Weil on 26 Dec 2008, 10:18 pm

Clueless? Or writing for a living in favor of the companies who pay the ads in their magazines?

Excellent point.

poseidonsvoice · « **Reply #95 on:** 27 Dec 2008, 04:28 am »

Quote from: David Weil on 26 Dec 2008, 10:18 pm

Clueless? Or writing for a living in favor of the companies who pay the ads in their magazines?

You hit the nail on the head on that one

or was it a brick wall,depending on the way you look at it

Anand.

chakija · « **Reply #96 on:** 27 Dec 2008, 09:24 pm »

Guys,
just one question about those who use Alpha full range and satisfied with results...
Are those with black or silver sticker on magnet ???
I have both and i can say that black version is much, muuuuch more linear than sliver one ! No sign of shouting from them ,but silver sticker alpha shouts like hell

gainphile2 · « **Reply #97 on:** 28 Dec 2008, 05:50 am »

I have the "black" version and it shouts too. But never compared with "silver one".

The shoutiness is easily tamed with notch filter as my previous post.

Graham Maynard · « **Reply #98 on:** 28 Dec 2008, 09:35 am »

What is the difference, the cone ?

Is it same shape and spec but coated differently, as if tropicalised ?

fine · « **Reply #99 on:** 28 Dec 2008, 10:53 am »

I have the Black.
http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1672