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Topic: Analogue to digital converter comparison

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Posted by Romy the Cat on 03-16-2007

ANALOGUE TO DIGITAL CONVERTER COMPARISON
by Kostas Metaxas

Procedure:

In all cases except for the KORG MR-1000, SOUND DEVICES SD744T and METRIC HALO[used with an Apple Laptop], I fed the outputs of the Stellavox SM8 to the A-D converter inputs [using my ENOSIS cables in all cases], then the SPDIF output of the A-D's was fed into the BNC SPDIF input of the Sound Devices 744T.

Absolute Reference:

For those of you who aren't used to the sound of a "holographic" recording, I have included some short samples of the legendary work of Bob Fine [Mercury Recordings] who was using essentially an AB set up wiith a middle "mono" channel. He was using the Telefunken ELAM 251s [AKG C12's]. His contemporaries Lewis Leyton [RCA RED SEAL] and Ken Wilkinson [DECCA] achieved similar results using the legendary Neumann M50s.

http://www.reel2reel.tv/ADC/Mercury_Bob_Fine_Chabrier.wav [15Mb sample 16bit/44.1k]

http://www.reel2reel.tv/ADC/Mercury_Bob_Fine_Chabrier2.wav [20Mb sample 16bit/44.1k]

You can purchase the full recording here.

The Comparisons:

All these files are 180Mb 5min sample 24bit/96k. You will need to download them and listen in a WAV editor since most computers won't play these files natively.

Sound Devices 744T, using it's line level ins/ADCs

http://www.reel2reel.tv/ADC/SD744.wav

Metaxas - Wolfson ADC - SPDIF output to Sound Devices 744T SPDIF in

http://www.reel2reel.tv/ADC/Metaxas_WOLFSON.wav

METRIC HALO with latest Apple Laptop

http://www.reel2reel.tv/ADC/Metric_Halo.wav

PRISM DREAM ADC - SPDIF output to Sound Devices 744T SPDIF in

http://www.reel2reel.tv/ADC/Prism_ADC_Classical_noise_curve.wav

LAVRY GOLD ADC - SPDIF output to Sound Devices 744T SPDIF in

http://www.reel2reel.tv/ADC/LAVRY_GOLD.wav

KORG MR-1000 [DSD] with it's proprietory DSD-PCM conversion software.

http://www.reel2reel.tv/ADC/Korg_MR1000.wav

The Concert:

BENAUD TRIO [violin, cello & piano] perform LED ZEPPELIN'S "STAIRWAY TO HEAVEN".

You can view a track from this concert to see how the mics/musicians were lined up. I was using Neumann M150s in AB and TLM50s in XY: http://www.reel2reel.tv/SCREENERS_WMV/__benaud_stairway-1a.wmv

Listen to the huge "weight" in the sound and the "dimensionality" or 3D realism of the instruments. To me this is the key. And this is the problem with all the digital location recorders I've tried. In general, they knock out the bottom octave [or "bloom"] and flatten the soundstage. Music through them sounds artificial and dry.

About Kostas Metaxas

Kostas Metaxas is an artist producing state-of-the-art Hi-End Audio systems [including digital transports/DACS,Amplifiers and Electrostatic loudspeakers] since 1981. He has received numerous awards [www.metaxas.com] and his amplifiers have been enthusiastically reviewed in Hi Fi magazines throughout the world. He currently only assembles "systems" to order for professional recording engineers or serious hi fi enthusiasts. The Metaxas ADC is a new product under development.

He has been recording concerts since 1986 although over the past 3 years [2004,2005,2006] he has filmed [in HD - www.exero.com ] and recorded over 150 concerts including legendary performers such as Charles Dutoit, Jean Yves Thibaudet, Konstantin Lifschitz, Takacs, Il Giardino Armonico, James Morrison, Mike Nock, ACO, ASQ, Jerusalem Trio, Yvonne Kenny and Fritz Hauser.

You can view this page by visiting: http://www.reel2reel.tv/ADC/ADC.htm
Posted by jessie.dazzle on 03-16-2007
Without completely understanding the post, I listened to all the samples (which by the way, will play immediately without doing anything if you have a mac...oops!). I first ran the files through my main system (there is a laptop + DAC associated with this system), and then listened to each file via a pair of fairly decent headphones, this time via the sound card of the computer.

In both cases I preferred the LAVRY GOLD and Metaxas-Wolfson files.

Also, to me the first two samples (for which there is no DAC identified) sounded as good or better.

I have never tried any of the DACs listed in the above post.

My experience would bear out that if done with care, the association of a HDD with your system can very much broaden your listening horizons, in that it will get you listening to your entire music collection. And...the quality of internet radio is imporving all the time.

For what its worth, and at the risk of running off subject, I use a laptop and series of external Firewire hard drives with a Wavelength Cosecant USB DAC (uses a single 6GM8 dual triode to the output transformer)... This may sound ridiculous, but despite the presence of Black Gate capacitors (oops!!), and the fact that this is a straight 16/44.1KHZ unit, I have up to now not been able to equal or better its performance with any other source I've owned or auditioned, regardless of sampling technology or price, stopping the research at about the $12K mark. I have not however compared it to what a good truntable might do (I am not equipped). Also, all evaluation was done in the context of my previous setup, consisting of good, but direct radiating speakers of "normal" sensitivity... The story may be different with the SET amps and horns, once I get more of them in place.

And who knows, I may be able to further improve the performance of this DAC by upgrading the capacitors.. Wink

jd*

Posted by Romy the Cat on 03-18-2007

The initials post was the body of email that Kostas sent to me and considering it’s format he presumed that I will me post it on my site. So, I did it (with his permission). I ran all those tracks once (some of them just a few seconds) and below is very brief log or my initial impressions. The files were running off my DAW, via Lynx 16 to Lavry Gold DAC. I do not interpret the result and juts print my row data.

Sound Devices 744T, using it's line level ins/ADCs

1) Slightly thin
2) The piano player should be shot in his head
3) Slightly transient challenge in upper bass.
4) At lower dynamic ranges looses dynamics.

Metaxas - Wolfson ADC - SPDIF output to Sound Devices 744T SPDIF in

1) The kids have very crappy instruments.
2) Sound Very slightly flat and hollow.
3) Though the sound is “better” but less “pregnant”, those I admit that the performance is very week.

METRIC HALO with latest Apple Laptop

1) Some crappy “clinking” noise
2) The lowest octaves are absolutely artificial
3) Sever lost of resolution and transients
4) Compression, Tone… everything… the sound is completely cooked…. trash it.

PRISM DREAM ADC - SPDIF output to Sound Devices 744T SPDIF in

1) For some reasons the tone is not there
2) Imaging is further as in 744T but was flatter
3) Moderate compression
4) Sound has some strange inner-echo
5) Very low contrast

LAVRY GOLD ADC - SPDIF output to Sound Devices 744T SPDIF in

1) Some thinness
2) Deficiency in lowers bass
3) Minor compression
4) Emphasis of unnecessary and artificial details – I do not like it
5) Low transients in upper bass, poor upperbass tone.

KORG MR-1000 [DSD] with it's proprietory DSD-PCM conversion software.

1) Minor compression
2) Very poor MF tone
3) Actual very poor tone everywhere. Unusable

Rgs,
Romy the caT
Posted by thylantyr on 03-20-2007
ANALOGUE TO DIGITAL CONVERTER COMPARISON

The sound I hear is akin to pops and clicks found when listening a vinyl recording
on all the tracks where some are worse than others. I don't think anyone of those
ADC's are responsible for this if the test was setup properly.

If they can setup a better test where we are not biased towards these pops
and clicks, then one can form a proper conclusion on the sound of conversions.
Posted by Romy the Cat on 03-20-2007

Thylantyr,

Yes, you have a point. It might be something fishy is going on in there and I have thought about it too. Still, I do not really see in Costa’s actions any rational for perpetrating the intentionally fraudulent tests.  Yes, his Metaxas-Wolfson ADC (whoever it is) sound more interesting then other exampled  AD processors but you do not see him commercializing his “better” product. As I understand Costa’s does purely for own benefits as he is actually is a practicing recording engineer… Sure, he might be a self-deluded as many others but do you have many others who present data about ADCin the format that Costa does?

Anyhow, sure it might be interesting to hear more tests, performed perhaps in more methodologically clean environment. It would be interesting also to plug into the game the Pacific 20-bit processor… The more the merrier… BTW, the pops and clicks were not soothe that annoyed. I did not bother myself to pay attention to the details of imaging as the sound right the way quite different from those converters… Was it the sound of the converters or Costa was laying with DCP? Who knows! You want to be absolutely certain you have to make your own tests. Without own experience everything aisle should be trusted as anything else coming from internet.

The caT
Posted by Romy the Cat on 06-16-2007

I was looking at the German-made TrueMatch RMC ADC:

http://www.stagetec.com/stagetec/e_truematch.htm

They claim the 137dB noise level and dynamic range of 159dB.  I wonder if the dynamic range of 159dB is a pure violation of the rules of thermodynamic. I am not convinced but I do not think that 159dB dynamic range ever exists in air…

The caT
Posted by Paul S on 06-16-2007
Why can't I just accept claims like these at face value?

If true specs and affordable, then they better stock up for an onslaught, never mind the sound quality.

Toss your vintage Neumann this way...

Best regards,
Paul S

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