Cutting from DSD sources ...

[mischmerz]

Fellow Trolls:

High quality audio is more and more getting into focus. A few of you may already be cutting from DSD sources, so I thought I share my experiences. We are using a TEAC UD-301 USB DAC that converts FLAC and DSD into analog audio. It can be hooked up to almost all computers, including Linux (no special drivers necessary). While playing "bit perfect" FLAC is easy with ffmpeg, there's no simple "free" solution to play DSD. Problem is, that DSD is streamed as "DSD Over PCM" or short DOP. This is a special protocol that wraps the DSD data into a PCM format - but it's not converted to PCM. It simply uses the PCM data format to transport the native DSD data. Most external DACs understand DOP - but ffmpeg can't produce it.

I searched for quite a while to finally find a little tool that converts DSD format into DOP PCM. I modified it to output it's data to stdout so that it can be fed into ffmpeg. I now have a solution that allows me to "play" bit perfect DSD on the command line and output it to the USB DAC.

More here: http://blog.michaelamerz.com/wordpress/playing-dsd-files-without-mpd/

Have fun.

Michaela

[phdutton]

Be interested to know how you get on. We have the DSD playback sorted (Sadie - SDIF - Prism ADA8), but I've yet to try filtering and cutting from DSD.

[mischmerz]

Our iRIAA has an "low pass" filter practically eliminating everything above 25khz on input. Rest is up to the analog chain.

m.

[gold]

I've cut DSD sources from a Sony Sonoma system that isn't mine. I was scared of the unfiltered out of band noise from DSD. It didn't prove to be an issue. I've asked for few years now if any of the stand alone DSD boxes can be synced with an offset for automation. So far the answer has been no. Has anyone successfully synced two DSD boxes with an offset ?

[mischmerz]

Has anyone successfully synced two DSD boxes with an offset ?

You are supposed to be able to sync Tascam DA-3000 with external clock sources. I have only one unit, so .. no need to sync.

mm.

[gold]

Syncing the clock is different from syncing one unit to another for multitrack like operation. You can sync one unit to another but there is no way to offset the sync for preview as far as I know. I've considered trying a delay line between the sync ports but I need two units in the same room to test before buying a pair.

[mischmerz]

Thats exactly why you can sync the Tascams - to do multitrack operations. Let me lookup the manual ...

mm.

[markrob]

Hi,

The unit looks to just have TTL level word clock sync, so I don't think a delay line there would do anything.

Mark

[gold]

I thought delaying the start pulse and having it free run might be close enough.

[markrob]

Hi,

I took a look at the manual. It looks like they use the S/PDIF ports in a special way to implement the cascade function. Work clock is allowed in addition to the cascade ports if you want to be sure you have phase accuracy across the decks. The magic comes from the cascade port itself. If you dive into how this is done at the nuts and bolts level, you could probably come up with an interface to do the delay, but I'm afraid it may not be easily possible with a simple audio delay line. It would be fun to try.

Mark

[gold]

but I'm afraid it may not be easily possible with a simple audio delay line. It would be fun to try.

So am I which is why I'd want to try it before buying.

[gold]

I thought a delay which passed the subcode bits transparently would probably work. I'm guessing that the magic is in the user defined subcode of the SPDIF stream.

[markrob]

Hi,

I'm guessing you are right. I don't think you can delay S/PDIF via an analog delay. I bet it would be trivial for Tascam to add an offset function via a firmware update. It might be worth it to talk with them to see if they are up for it.

[gold]

Hi,

I'm guessing you are right. I don't think you can delay S/PDIF via an analog delay. I bet it would be trivial for Tascam to add an offset function via a firmware update. It might be worth it to talk with them to see if they are up for it.

I've talked to them at AES a couple of times. They didn't seem very interested.

[jlapointe]

Hi Paul,

I think you could make this work with two Tascam units in sync, one playing a file prepped with the preview offset. You could use the free Tascam DSD editor to edit a blank piece of audio of the appropriate length onto the front of the "program" file. Program file in machine #1, preview file in machine #2, sync playback start and you're on your way.

Best,

- J.

[gold]

Hi Paul,

I think you could make this work with two Tascam units in sync, one playing a file prepped with the preview offset. You could use the free Tascam DSD editor to edit a blank piece of audio of the appropriate length onto the front of the "program" file.

Thanks J! I have a friend with one. If I get one we could share when the odd DSD job comes up.