Reclocking and Jitter Reduction

Hi Harry, can you give more details of your demos? cables, Lavry configuration?
I have upgraded the transport from an M-audio card to a Lynx AES16 with the same DAC and I hope this will be noticeble too.
In a few days I will receive a custom AES digital cable for connecting them. Lynx card is supposed to have an excellent reclocking technology.

I'm not sure it's quite that simple.

The Lavry DAC in crystal mode - buffers the incoming digital signal and then clocks this out locally. So this should isolate the DAC from any upstream 'jitter'.

However, the buffer is only so deep. So if the source is causing larger lags - CPU loading / whatever - this could still have an effect - as obviously would data loss caused by non-optimal connections.

Are the files you are streaming Lossless compress or uncompressed? Do you notice any difference?

I'm getting fantastics results with a Mac/Intel/Lavry combination - and I also cannot distinguish between lossless and AIFF. I suspect the dual core Intel with high clock speed is responsible.

Cheers

Richard

goldfinch hi --

Not sure can give a great deal more info. Lavry is set up as what I assume is "standard", internal jumpers moved and flashback cables. From the AppleTV to the Lavry I use a Monster iTV cable - all fairly normal stuff I assume. All files are apple lossless and sit on the AppleTV drive.

I was surprised to be able to hear the difference between AppleTV/Lavry and the CDP (Meridian G08) but the differences were there. I want to remove these differences and believe it must be possible.

Loads of information out there - reclocking devices, cables etc etc but also massive amounts of noise and violent disagreements.

Let us know of any improvements that you find!

So the AppleTV is reported to use a

"1.0GHz Pentium M-based chip (code-named "Crofton")"

So between 1/3 and and 1/4 of the processing power of a Mac Mini. Again, just a thought.

paremus hi --

I am not entirely sure what the Lavry actually does having just read through a couple of very heated threads on their forum! I am very pleased with the quality but the CDP was better - I m sure I can get it to that quality. Just don't know how.

Files are lossless - not streamed, stored on AppleTV hard disk. Haven't tried a lossless against WAV/AIF comparison as intellectually I thought it would make no difference but will give it a go and see what I hear.

There is no going back to CDP. Having the Genius function has now kind of sealed the deal: I can't praise this any way near enough to do it justice. I know it's not original (Pandora, Last.fm, Spotify) but when used in conjunction with uncompressed audio puts you right back in connection with your entire music collection. I only have about 400 CDs but it would take a couple of years to listen to them all. Genius allows you to take a very pleasant, guided walk through your collection and fall in love with it all over again.

Bringing it back to NAIM I would like to upgrade my 72/HiCap/180 and will do once I have optimised the source.

quote:

Originally posted by paremus:
So the AppleTV is reported to use a

"1.0GHz Pentium M-based chip (code-named "Crofton")"

So between 1/3 and and 1/4 of the processing power of a Mac Mini. Again, just a thought.

Good point! I have a Mac Mini although not sure if it is Intel based or not - haven't used it or a while (sat under the television doing nothing). Will fire it up and give it a go when I have time.

Having said that, though, the AppleTV can stream in H.264 at 3500 Kbps and out to the TV such that I see no difference between that and DVD. That's not too shoddy - but maybe audio (although simpler one would assume) needs to be more precise.

Suspect one wouldn't be as sensitive to visual jitter.

If the Mac is an Intel one give it a go. If powerPC, then its probably only on par with the AppleTV processor wise.

Cheers

Richard

Also lossless, whilst identical from a data perspective, will place a heavier load on the processor - as the file needs to be uncompressed.

Simple test would be to compare lossless to AIFF - if there is an audible difference, probably argues for a faster processor.

Cheers

Richard

Lossless decoding should be very cheap - but everything is worth a go!

Don't disagree, but just wonder w.r.t. audio streaming if CPU scheduling behavior is a factor.

Interested in your findings - either way.

Cheers

Richard

2 points.

A 1ghz processor is more than enough to push some music files about, espeically as its basically all its doing.

And an appletv is designed to push audio and video around. It can handle 5.1 surround sound as well as a basic OSX and video upto 720p. Its not struggling with the music.

There is no harm if Mr Wombat simply prefers the sound of the meridian.

In which case I would use the digital out on the ATV into a meridian dac.

quote:

Originally posted by garyi:

There is no harm if Mr Wombat simply prefers the sound of the meridian.

In which case I would use the digital out on the ATV into a meridian dac.

Maybe so - but I am not entirely sure how I would find out I don't know of anywhere currently where one can audition multiple DACs, multiple computer based sources and any combination thereof. I cannot tell if the issue (if there is one) is in the AppleTV, the cable or the current DAC (Lavry). I do not know if a reclocking device or an outboard soundcard would make a difference. All I know is that to my ears the Meridian produced a better result that the AppleTV/Lavry (through NAIM amplification). (I also know moving from entry level pre/power to 282/250 produced a beautiful difference but that is another thing entirely).

The only place to get information is through forums, computer audio sites and professional sites. I trust these to give me options but not to select my equipment for me - only my ears can do that!

If anyone wants a neat business opportunity in these trying times this could be it - a computer based audio business with the opportunity to audition multiple DACS and configurations. I'd pay a visit!

Garyi,

Afraid its not quite that simple. Its not a matter of pushing around files - but any timing delays introduced by data being processed by the CPU. This is very real if you are interested in low latency messaging (which is part of my job) - with realtime and scheduler based OS's having very different profiles w.r.t. 'message jitter'.

What I don't know is whether any of this is relevant. Given how sensitive the ear is to timing - it may. But just idle speculation on my part.

It may well be that Harry simply prefers the Merdian - which is fine!

Harry - I've an old Mac PPC - I'll try this against the Intel at some point


Cheers

Richard

quote:

Originally posted by goldfinch:

I have upgraded the transport from an audio card to a Lynx AES16 with the same DAC and I hope this will be noticeble too.
In a few days I will receive a custom AES digital cable for connecting them. Lynx card is supposed to have an excellent reclocking technology.

Hi goldfinch -

Could you let us know how you find the Lynx card - I have read some very good things about it. I have also read that if used on the PC legacy drivers etc sound better and that the AES16e is recommended for Mac Pro.

quote:

Originally posted by goldfinch:
Hi Harry, can you give more details of your demos? cables, Lavry configuration?
I have upgraded the transport from an M-audio card to a Lynx AES16 with the same DAC and I hope this will be noticeble too.
In a few days I will receive a custom AES digital cable for connecting them. Lynx card is supposed to have an excellent reclocking technology.

Technically, I think it's how it applies the master clock from the original instructions and is not reclocking when chosen as the primary sound card though it can reclock from other sources. How's it sounding?