Lynx AES16 SRC revisited

[Suteetat]

Hmmm... I found something very interesting today. According to Lynx faq and a few posts in Lynx support forum , AES16 SRC only support rate conversion at its input only, not its digital output.

I am quite confused.

I hooked up my Lynx AES16 SRC to Esoteric D-05 via dual XLR with D-05 as master clock with clock output to AES16 SRC.

 

When play back 16/44.1 file, if I set clock output on D-05 to 176, it seems that D-05 senses 176 input on its dual XLR mode, showing dual 176 on its screen. Set the clock output to 88.2 kHz, it will show "dual 88.2" on its screen. Lynx mixer also shows similar reading.

 

If I play 24/176 file, set clock output to 176, everything works as intended. However, if I set clock output to 88.2 kHz, D-05 screen will show "dual 88.2" eventhough I am playing 24/176 file. Chaning sampling rate in Lynx Mixer screen does not do anything as far as D-05 input is concerned, sampling rate shown on D-05 always match its clock output.

 

I am not sure what's going on. Changing clock output on D-05 from 44.1 to 88.2 to 176 does change the sound to a certain extent.

 

If I am reading lynx faq correctly, regardless of clock input frequency from D-05, if I play 16/44.1 file, d-05 should only receive 16/44.1 signal, is that correct?

May be the D-05 input automatically follows its clock output in this mode, regardless of the actual incoming digital stream.

 

 

 

[Suteetat]

Hmmm... I am running a few more tests and I am even more confused.

 

According to Lynx faq from this link: http://www.lynxstudio.com/support_faq_result.asp?q=173

"Can I change the sample rate of outgoing audio using the Sample Rate Converter on the card? (SRC version)

All OS

 

No. With the AES16-SRC, only incoming signals can be sample rate converted."

 

I took out the master clock from D-05 and use Lynx internal clock, running single AES/EBU.

Changing tracks from 16/44 to 24/88, 24/192, Lynx mixer identify the correct frequency and D-05

display XLR1 44, XLR1 88, XLR1 192 appropriately (with rate lock box unchecked).

However, if I play 24/192 and click rate lock box on Lynx Mixer, then play 16/44 tracks, Lynx mixer and D-05 continue to display rate at 192 despite playing 16/44.

So what is this supposed to mean?

 

I also tried 2nd set of test with dual wire out, D-05 clock input into Lynx (which is working properly only at 88 kHz and higher, at 44 kHz, only one channel would come out). If master clock is set at 44, playing 16/44 track, only one channel comes out which is no surprise. However, when I play 24/176 tracks, D-05 continue to display "dual 44" and only one channel comes out.

 

To me, this means that somewhere, there is upsampling and downsampling going on in there.

One thread in lynx support forum : http://www.lynxstudio.com/forum/forum_posts.asp?TID=2505&KW=AES16SRC&PID=14356#14356

basically say that when I click rate lock box, window somehow would do all the upsampling and downsampling for me and not Lynx card. I thought using Mediamonkey with asio or MM waveout would bypass kmixer and all those window meddlng stuff but I guess it is not.

 

I guess after all, a couple of lessons to be learned:

1) I did not need to spend extra money on SRC version of AES16 since it does not really do what I thought it would anyhow (upsampling files at hardware level, not at window level).

2) Using external clock will require that I adjust clock input to match the file being play manually since it seems that

if clock frequency is different, window will automatically upsample or downsample files being played to match clock input.

 

However, I have to say that I generally prefer the sound when clock input is set to 176 better than at lower or native frequency whatever it is but wonder if this is something that you can also achieve with regular AES16 card.

 

 

 

[The Computer Audiophile]

Hi suteetat - As you said, using an external clock requires one to manually change the sample rate on the hardware. It's like using a manual transmission. The results can be great but convenience must also be considered. You can accomplish everything you need with the regular AES16 cards. That's totally cool if you prefer the sound when the clock is set to 176.4, but I highly recommend setting the clock to match the native sample rate of the material you are playing.

 

[Suteetat]

Hi Chris, I did a lot of listening with various clock frequency, even after I found out about the whole upsampling issue which would give me a little bias toward no window upsampling as being ideal, playing 16/44.1 tracks with clock at 44.1 kHz, upsampling at D-05 end to 176, no conversion or 44.1 converted to DSD, no clock, vs upsampling to 176 at computer end then convert to DSD or no conversion at D-05 end, overall, I still prefer upsampling to 176 at computer end then convert to DSD at D-05 with clock input from D-05 at 176.

From D05 end, I prefer sound of DSD conversion over no oversampling or 2x-4x oversampling regardless of computer output type. Together with upsampling from computer end, the sound is more mellow, less edgy but at a slght cost of being a bit less crisp on some tracks which is the way I prefer. Other will disagree, I am sure.

 

However, after being said and done, I have been considering changing DAC. My local dCS dealer has some interesting deals since they had quite a few trade in from their customers who upgraded their Elgar Plus stacks to Scarlatti stacks so they do have a few Elgar Plus at all most attractive price! However, I am not sure how well dCS would work with Lynx since dCS master clock can only generate 44.1 and 48mHz clock frequency so playing 24/88, 24/176 tracks via dCS with its master clock may not be possible.

I guess if I want to change DAC, it would have to be either Berkeley which forego messing with clock altogether or Esoteric or other DAC that support higher clock input/output as well. Did you ever have a chance to compare Esoteric vs Berkeley?

 

[The Computer Audiophile]

Hi suteetat - There are a few people here on CA with dCS units and I know they use Lynx cards. Once they figured out how to configure everything I believe they've been pretty happy. I have not compared the Alpha DAC directly to an Esoteric unit, but I know someone who currently has both. I hope to hear his opinion on the two very soon.

 

[Suteetat]

I definitely would like to see how other people with dCS fare with Lynx, especially if they use dCS master clock and able to play back 24/176 files properly or not since I can't seem to get D-05 to output clock at 44.1 to Lynx and have Lynx playback at 176 kHz properly.

 

Another issue with dCS is that its single XLR connection supports upto 88kHz and dual wire supports only 88-192kHz according to dCS site so there seem to be no easy one connection for all playback. I guess you can keep switching between dual wire and single wire mode but that is a bit less convenient when you play back various types of files in a row.

 

Another quick question, I also tried clock output from Lynx to D-05 using terminal B on Lynx card but D-05 would not lock on to Lynx clock output. I don't see anything in Lynx manual about specific setup except for using terminal B for clock output. I hooked it to clock input on D-05 and in menu of D-05, set it to clock in mode but that does no luck so far.