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View Full Version : Bob's high-quality SRC (plug in)?



Naturally Digital
06-26-2004, 11:17 PM
Hi,

Just trying to "keep it light" with the title! :D Please don't think that I'm trying to 'push through' any features by discussing these types of things. I just think it's great to share ideas on this forum. :)

We were talking SRC on another thread. I actually had a big long reply typed the other day but I hit the wrong key and deleted it by accident. I was so ticked that I didn't bother re-typing it. That is exactly why I don't use web-based email. :mad: Anyway...

We know that with multiple passes/steps, just about anything is possible with SAWStudio. As far as I'm concerned it could stay just the way it is for years and I'd be perfectly happy. The thing is, I've always liked the 'realtime' aspect of SAWStudio and for various reasons I tend to use it that way. Often I record a loopback from somewhere in the chain, onto a new track for my final mixdown/master/process... whatever. I've always favored the idea of a 'one-pass' process while working. I find that making revisions or changes after delivering a test master is sometimes easier or quicker (although sometimes it isn't).

I don't even know whether this could work or not but I've been thinking about this discussion and I came up with a way that I would use Bob's SRC plugin if it existed. I think it could replace some hardware bits if used creatively. Imagine this scenario: :rolleyes: (don't know why that smilie is called 'sarcasitc' or 'roll your eyes'. Personally I like to think of him as 'pondering'...). Let's say...

I receive tracks from a client for mastering. They're delivered on CDR as 24bit/48Khz wav files. I load them into saw, using the common 'staircase' mastering layout (one song per track, end to end, assembled in one EDL). I've set the multitrack resolution to 24bit/192Khz and the realtime SRC to highest quality. All plugins/internal processing would be kept at this resolution. Say I'm monitoring at 96Khz (the limit of my D/A). It would be nice to use a high quality SRC on the output of SAWStudio to drop down to 96Khz. There may be some soundcards that could SRC the stream I guess but my LynxOne (digital out) doesn't know what 192 is.

Now say we've got a piece of hardware we want to use on the Aux bus for reverb and it only supports max. 48Khz SR. In my case it'd be the Mixtreme but it could just as easily be a Lexicon PCM80 connected by s/pdif or whatever. Imagine being able to patch in an SRC to the AUX out, before the hardware. (I know there's no FX patch point there now but hey, it could be added. ;) ) If we were mastering, this might be on an output but you get the idea. Multiple streams going in and out of SAWStudio, at any SR...

Would this even be possible??? I'm just wondering if there isn't some potential for ground-breaking things here.

Just some thoughts.
Thanks for reading.
Dave.

Bob L
06-27-2004, 12:48 AM
No argument that an SRC plug would be interesting.

Of course SAWStudio currently allows the multiple samplerates to all co-exist at the same time already... so adding them to the out buses and such should be no problem technically.

I have a lot on my plate already... we'll just have to see what happens. :)

Bob L

TotalSonic
06-27-2004, 01:26 AM
Dave -
I'm not quite sure what you are getting at here. If your cpu is fast enough you can already use SAW's highest quality src algorithm for real time playback. Most likely if you are just processing a single stereo track at a time a P4 2.8GHz box should do the trick fine. I don't understand why a SAW SRC plugin would really be needed.

If we're talking about mastering the majority of pro mastering studios that I am aware of usually do all all analog processing (usually eq and compression) in one pass from da to ad. Digital processing is then done at the highest resolution of the received files. Generally any digital peak limiting would be the second to last stage - with conversion to final bit rate and sample rate the final step.

Personally, if I receive 96kHz files, for the final conversion it gets sent to the analog realm via Lucid DA9624 and captured back through ad to 16bit/44.1kHz. To me this is a good way to insure that the conversion is done essentially artifact free.

Some other studios use dedicated digital hardware sr converters - with the boxes by Weiss & Lavry (both of which I believe operate at 48bit fixed point) generally being the most respected.

I've been meaning for a while to post some src comparison files between all the src tools I have (SAWStudio, r8brain, Cool Edit 2000, ReSample, the Roland SR-2 digital hardware converter, and loop back via da-ad via Lucid and Lynx) - but I've been distracted by lots of other things (like working!) so it keeps getting delayed. I've also been meaning to post a dither shootout too - I just need more hours in the day!

I have yet to receive in my work (or frankly, to even hear) 192kHz files. Dan Lavry, a very brilliant designer who makes some fantastic sounding ad/da boxes, recently wrote a pretty damning white paper on 192 where he had come to the conclusion that 192 offered no audible improvement over 96 and that if you wanted a better sound you should just invest in a better converter instead of doubling the space the file takes on your hard drive. Obviously I haven't drawn my own conclusions yet - but so far the point has been moot because I've never had anyone requesting delivery of their mixes to me at 192.

Best regards,
Steve Berson

Dingo
06-27-2004, 07:01 AM
http://www.24-96.net/dither/

Check this site out. It should answer all of your questions about dither. You can listen to samples of all of the dithering algorhthms out there and pick the one you like best. you can do a blind test id you wish too so you won't be biased by the one you paid for! You can also see which dither has come out on top. Very interesting. It isn't even close.

mghtx
06-27-2004, 07:59 AM
Thanks for the link Dingo. Very Cool.

Naturally Digital
06-27-2004, 08:52 AM
Dave -
I'm not quite sure what you are getting at here.
That's OK Steve. No biggie. :)





Dan Lavry, a very brilliant designer who makes some fantastic sounding ad/da boxes, recently wrote a pretty damning white paper on 192 where he had come to the conclusion that 192 offered no audible improvement over 96 and that if you wanted a better sound you should just invest in a better converter instead of doubling the space the file takes on your hard drive.

Best regards,
Steve Berson

You'll notice that in the scenario I presented, no files are created at 192kHz. Only the internal processing (in SAWStudio) is done at the highest samplerate. No extra HD space needed.

Take care Steve,
Dave.