Gapless but glitchy - some tracks beginnings squelched.

[Ladyfingers]

An AVS forumite says that the problem is that the Squeezebox S/PDIF output lacks clock frequency synchronisation.

I don't know if this can be remedied with a plugin, or if it's possible to buy an S/PDIF repeater that somehow adds sync.

Any ideas?

[Phil Leigh]

An AVS forumite says that the problem is that the Squeezebox S/PDIF output lacks clock frequency synchronisation.

I don't know if this can be remedied with a plugin, or if it's possible to buy an S/PDIF repeater that somehow adds sync.

Any ideas?

I read that thread on the official NAD forum - it's nonsense (sorry).

The Touch does of course have an internal clock (two of them in fact!) and it is the NAD that is supposed to recover the clock from spdif...

The fault lies with the NAD - it would appear to be related to the fact that the NAD (as with most AV receivers) needs time to lock/decode the signal to know if it is stereo PCM, DD, dts etc. This will require a firmware fix to the NAD.

The input circuits of most (all?) modern receivers are really optimised to handle multi-channel PCM and stereo is unfortunately handled as an afterthought.


The Touch has been extensively tested and altered during Beta to ensure that its spdif handling is correct. There was a nasty bug (long fixed) that caused the pcm to revert to 44.1 during track transitions/pause etc even when the track playing was not 44.1 - this caused problems for some DAC's... clicking noises etc.


Many DAC's have muting circuits (various designs) that will kill the analogue output if lock is lost - this is necessary because the noise that is produced otherwise is very objectionable.

So the fact the NAD display "PCM" indicator is going on/off does NOT mean that the spdif signal lock is being lost, it means that the NAD is re-evaluating the nature of the incoming spdif stream to determine its format (DD, dts etc). It would appear that this process is being triggered by the arrival of (even the briefest moment of) digital silence... and it is taking too long!

My M1 DAC (and X-Dac) lock and hold lock perfectly through gapless track transitions, pause and stop conditions.

By the way, that thread mentions the Benchmark DAC and plenty of those are in use by forum members here - no-one has reported a problem AFAIK.



Do you have any truly gapless albums - maybe live albums? - what happens between those tracks when you play them back? - you should hear a seamless transition...

[Ladyfingers]

I read that thread on the official NAD forum - it's nonsense (sorry).

The Touch does of course have an internal clock (two of them in fact!) and it is the NAD that is supposed to recover the clock from spdif...

The fault lies with the NAD - it would appear to be related to the fact that the NAD (as with most AV receivers) needs time to lock/decode the signal to know if it is stereo PCM, DD, dts etc. This will require a firmware fix to the NAD.

The input circuits of most (all?) modern receivers are really optimised to handle multi-channel PCM and stereo is unfortunately handled as an afterthought.


The Touch has been extensively tested and altered during Beta to ensure that its spdif handling is correct. There was a nasty bug (long fixed) that caused the pcm to revert to 44.1 during track transitions/pause etc even when the track playing was not 44.1 - this caused problems for some DAC's... clicking noises etc.


Many DAC's have muting circuits (various designs) that will kill the analogue output if lock is lost - this is necessary because the noise that is produced otherwise is very objectionable.

So the fact the NAD display "PCM" indicator is going on/off does NOT mean that the spdif signal lock is being lost, it means that the NAD is re-evaluating the nature of the incoming spdif stream to determine its format (DD, dts etc). It would appear that this process is being triggered by the arrival of (even the briefest moment of) digital silence... and it is taking too long!

My M1 DAC (and X-Dac) lock and hold lock perfectly through gapless track transitions, pause and stop conditions.

By the way, that thread mentions the Benchmark DAC and plenty of those are in use by forum members here - no-one has reported a problem AFAIK.



Do you have any truly gapless albums - maybe live albums? - what happens between those tracks when you play them back? - you should hear a seamless transition...

Thanks for taking the time. Appreciate the help.

Yep, my truly gapless albums (continuous transitions between tracks, even a little tape hiss) are played perfectly gapless. It's just albums that have the inter-track noise digitally removed where the NAD stumbles, and skipping, pausing etc. Any break causes lock loss. Irritating as all get out.

All this said, my DVD player seems to manage better, so I wonder what it's doing to keep the S/PDIF alive during silence. Any ideas?

I do find the NAD's DAC locking period pretty close to unacceptable for HDMI, I must admit. It's a damn shame, because the amp section is wonderful. I need to get a firmware update, though. Just very hard for me to do at the moment.

[Ladyfingers]

Problem solved. Mostly.

I managed to browbeat NAD into allowing me to update the firmware myself, and everything's working okay now.

I still get the openings of albums clipped off as when the player is re-awoken it seems to not be putting out a signal. 44.1k is maintained for a few seconds between tracks, so the receiver maintains lock.

I know there's a setting in the web controls that delays initial playback for a second or two to allow lock on to happen before playback. Can this somehow be selected for USB playback?

Failing that, a simple plugin that played inaudible noise for a second or two before the first track after sleep seems like an easy fix.