DIY Emerald Physics CS2 Clones

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Russell Dawkins

Re: DIY Emerald Physics CS2 Clones
« Reply #120 on: 9 Sep 2009, 10:21 pm »
yes! If I'm not mistaken, 1200 sq m is 10,800 sq ft. That would be a small aircraft hangar!

Victor

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Re: DIY Emerald Physics CS2 Clones
« Reply #121 on: 10 Sep 2009, 04:35 pm »
oops. it's not a hanger I meant 120 sqm ofcourse.

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #122 on: 16 Sep 2009, 08:18 pm »
I have to report some findings about this EP cloning.

I have been challanged by Ric Schultz to time align my MJAO passive 3-way OB, see: earlier in this thread. I will come back to this soon after my vacation about the 25th October.
In the mean time I have been experimenting with my 2 Alphas and the Vifa D27TG35-06 going active with DCX2496. I received two Vifas after a long wait and recognized that they could be put in my MS-100CHQ cut outs in the MJAO baffle. I also performed the tweak suggested by Ric and cut off the back of the Vifa's dual chamber.

Well, what to say. This speaker as now presented 2 Alphas and the Vifa D27TG35-06 crossed at 950 Hz active is so far the best OB I have experienced.
The Alphas bass/middle may be a bit too dark in direct comparison, with for instance the MJAO, but still very good and certainly benefitting from the active drive. On the whole they put out a performance second to very few in direct comparison. And I have a hint how to perhaps overcome this weakness of a bit darkness. The Vifa however is extremely good. You can't really imagine how precise and detailed this tweeter presents itself, it is amazing. The whole speaker benifits from this and altogether you get a sound and image quite superb. The active driving of course is really responsible for this. You may be astonished how little energy really is transmitted by the tweeter at 950 Hz and above and how big an impact it really does when active. No EQ was applied to the tweeter. My concern now, will the waveguide really 'improve' the Vifas ? No other of the proposed bass tweaks were performed. The link to Ric's 'Modding' page is: http://www.tweakaudio.com/EVS-2/Modding_the_Emerald_Physics_spe.html .

There are some pictures accompaning these statements: First the baffle with the Vifas put in place:



then the tweaked Vifa tweeter:



and last a measurement of the tweeter frequency response at 50 cm in front and in back, the higer output is from the front, 1 KHz crossover, 10 dB division:



/Erling


« Last Edit: 17 Sep 2009, 06:01 pm by scorpion »

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #123 on: 19 Sep 2009, 10:57 pm »
Commenting a bit more about this setup.  I use two Behringer units. First every signal is AD-ed and/or if digital from the beginning, upsampled to 96 kHz 24 bit in a SRC2496 before entering the DCX2496. These units fit as hand in glove. The SRC2496 is an AD/DA and also upsampling device very much underrated I think. What's eventually going on in the DCX is certainly benefitting from this pre procedure.

For the DCX2496 I have mounted 3 bass filters, one BP at 60 Hz at + 2 dB with a Q of 2.0 and a similar BP at 132 Hz + 2 dB and 2.0 Q and last a BP filter at 368 with - 4 dB and a Q-value of 4. This is all the filters I have mounted and they should be more or less optimal in my room. No tweeter filter. The crossover between the Alphas and the Vifa27 is at 937 Hz LR 48 dB/oct. I tried to listen to music at very high volume to establish this. There are differing specifications now for the Vifa unit if you compare what is written on the Tympany site or what is published for the units presumably produced in Denmark before the transfer to Chinese production. I have however applied the suggested Zobel of 7.0 ohm + 1 mH + 69 uF over the Vifas, to what help I do not really know.

The Alphas are a tiny bit on the dark side so I don't think that felt on the inside of the chassis is really called for. Damping the outside might still be a good idea. The Vifas might very well be as near perfection as you can come, at least for the price, when tweaked for dipole performance as suggested by Ric Schultz. The forward/backward power relationship is perfect.

I have done extensive listening to two records that I am very familiar of their recording venues. The first is the famous Audiophile record 'Jazz at the Pawnshop 1' recorded in the Stockholm club named Stampen. I often visited that place in the 70'ies so I have a good knowledge of the sound and atmosphere. These speakers put out noting but the real thing. Quite amazing. The other record is the BIS SACD presentation of Norrköping Symphony Orchestra and Ronald Brautigam playing Beethoven Piano Concertos, in this case No 1 & 3, from the Louis De Geer Concert Hall in Norrköping. This hall is now 15 years old and I have visited it during all the seasons about twice a month for concerts so I know a bit how it sounds. And also this record, however multi-miced evidently, does give you an impression of how it would sound as a regular concert performance. In all very enthralling, indeed.

/Erling
« Last Edit: 20 Sep 2009, 09:30 am by scorpion »

Russell Dawkins

Re: DIY Emerald Physics CS2 Clones
« Reply #124 on: 20 Sep 2009, 07:21 am »
A good tip about the SRC2496, Scorpion. That's the second time I have heard this said, so now it is time to try to find one, used of course.

Thanks for this and also for the large number of information-rich posts you have made over the years.
Is your DCX2496 stock?

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #125 on: 20 Sep 2009, 10:12 pm »
Both units are stock as of now. But I have three AK4396s lying around and I will do Scott Endler's proposed output mod when I can find someone able to put these tiny things in place for me and then complete with a 6-channel volume control. I think that the stockversion is quite adequate, but exchanging with newer chips and bypassing a lot of output-electronics is probably a good idea. I bought the two units at the same time and have run them like this all the time.

By the way the somewhat obcessed Lukasz Fikus has gone crazy about the SRC on his Lampizator web: http://www.lampizator.eu/LAMPIZATOR/TRANSPORT/behringer/Behringer.html:)

/Erling

jkelly

Re: DIY Emerald Physics CS2 Clones
« Reply #126 on: 23 Sep 2009, 07:39 pm »
Erling,

Can you describe the process you used to cut off the back of the tweeter?
How far back from the end did you cut?  What tool did you use to cut?

Thanks,

Jeff

jkelly

Re: DIY Emerald Physics CS2 Clones
« Reply #127 on: 24 Sep 2009, 11:39 am »
Erling,

How does the Vifa sound with just one Alpha 15"?
I may try replacing the B200 / single Alpha 15" system with the Vifa and active crossing it at 950.

Jeff

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #128 on: 25 Sep 2009, 09:19 pm »
Jeff,

I used a hacksaw to cut off the last millimeters from the plastic back.

From the comparison with the MJAO I am actually thinking of introducing my B200 in this setup moving the Vifa crossing up a bit and really go active.

/Erling


benzene

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Re: DIY Emerald Physics CS2 Clones
« Reply #129 on: 26 Sep 2009, 09:30 am »
Erling:
Sorry to cut into this thread. I realized that you're real good  :thumb: at those technical stuff , eg. frequency graph measurement & etc. I would like to ask you if i only have the DCX2496, and i wanna try out the auto align for time delay setting, which type of microphone is better? Is the auto align setting in DCX2496 reliable?
I'm currently trying to get the sound right on my OB.
And how do we determine whether what EQ we need to apply in the DCX2496 to make the sound right?
I'm sorry if this seems like some stupid questions, as i just started into this hobby for a year & still learning without any electronic background knowledge.  :oops:
Thanks in advance.

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #130 on: 1 Oct 2009, 03:40 pm »
Sorry Benzene,

I am far away from home on vacation, therefore no answer.
With dipoles you cannot time-align but with physical placement of speakers. No digital alignment will do any good.

To determine EQ I have used a simple homemade mic from Panasonic WA-61 module. It works very well. Measurement system is ARTA, available at the net.

/Erling

sfdoddsy

Re: DIY Emerald Physics CS2 Clones
« Reply #131 on: 13 Oct 2009, 09:56 am »

Ric Schultz

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Re: DIY Emerald Physics CS2 Clones
« Reply #132 on: 14 Oct 2009, 11:15 pm »
I know I am repeating myself here, but here goes:

You must time align all drivers.  The Behringer can do this very simply....once your system is in pretty high tweaksville, you should be able to hear the smallest amount of time alignment distance allowed in the Behringer.....delaying it forward or backwards...it should be easy to hear.  The Vifa tweet with the back cut off is not a true dipole.  The felt blocks most sound from coming out the rear.  It does have some sound coming out the rear but nothing like what is coming out the front.  Please time align....you can do this physically or electrically but it makes a huge difference.....in all speakers.

You must felt around any driver (in any speaker) used from 1K on up.  The diffraction will smear the sound and make it brighter.  Cover everything except the actual part of the driver that moves.

You must constrain layer dampen the baffle.  A single piece of plywood or MDF is going to muddy the sound super duper.  2 15 inch drivers have all the bass and warmth you could ever want.  You don't need baffle noise.  A brace all the way up the back will help even more as well as mounting the woofs via their magnets.  Highly refined particle board is better than MDF....but still you want at least two layers with Green Glue or other damping glue in between.

You must constrain layer dampen the entire back of the Eminence drivers.....BIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIG difference.  You won't believe how fast these things are when covered with EAR SD40AL (Percy sells it).

« Last Edit: 16 Oct 2009, 04:13 am by Ric Schultz »

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #133 on: 21 Oct 2009, 01:40 pm »
Hey Ric, this was only a test setup.

But quite revealing I think. All-thogether with active EQ you can really make the Alphas very authoritative speakers. Certainly very listenable. With this combo I do find the whole sound to be a bit on the dark side even though Vifas was not treated any. Crossover at 937 Hz 48 db/oct. The back output, as shown by my measurements, is not insignificant. But I have tried DCX2496 alignment and you are right there, I can really hear when things are right.

It's a bit funny how good the Alphas sound, but when you listen carefully you would realize that a good midrange would not be out of place. What I miss is the openness a good unit can supply. So here we go !  :)

But as the speakers stand now I could almost have them for the rest of my life, so good is the illusion ! On the Dark side of the Moon ?

/Erling
« Last Edit: 21 Oct 2009, 06:54 pm by scorpion »

scorpion

Re: DIY Emerald Physics CS2 Clones
« Reply #134 on: 6 Nov 2009, 06:22 pm »
Hi Ric,

I will take the Alpha15 Vifa combo as pictured to a diy-show arranged by our Swedish Hi-Fi Forum in Uppsala November 14th. All in all I think it is very good but perhaps a bit on the dark side. Units match well in sensitivity wihout waveguide so the only real EQ done is 12 dB/sloped filter from 100 Hz downwards at 6 dB gain, implemented in the DCX2496. The Vifa tweeter is delayed by 20 cms, which by listening is deemed best. Measurements then show  40 - 20000 Hz +- 3dB at sweetspot in my living room. I hope I will have a lot of comments at the show. It is of course not really an EP clone with no waveguide in place.

But I now also fully understand your post earlier. I have been experimenting with the Dayton waveguide and the Vifa is quite another loudspeaker with that.
Very bright as treble is amplified but also wide spread. So damping is called for and also damping of the waveguide like you have proposed should be done. Regarding the Alphas I will damp the back surface left round the spider with felt and also damp legs with bitumen on the outside.

/Erling
« Last Edit: 7 Nov 2009, 12:17 pm by scorpion »