View Single Post
      02-04-2012, 02:20 PM   #9
VP Electricity
Brigadier General
VP Electricity's Avatar

Drives: F34 xDrive
Join Date: Jan 2008
Location: portland oregon

iTrader: (3)

Originally Posted by 808MGuy View Post
In this configuration, is it basically acting as a MOST to toslink converter?
That is how I'm using it. Mobridge already had the DA1, which had ONLY Toslink out.

Originally Posted by 808MGuy View Post
Since you have a DSP downstream, would you be EQing the signal 2x?
I would be, but I'm only viewing the iDrive EQ as a fancy tone control - the P-DSP is for the advanced tuning. So far I haven't touched the iDrive EQ anyway, but I think having access to it is cool.

Originally Posted by 808MGuy View Post
Would the OEM volume control still work when using the toslink output?
Yes, it does, and the DA1 to a BitOne worked too. We posted an install some time back with a DA1 to a BitOne to the client's McIntosh amps. Getting the BitOne to work with the Toslink is kind of a pain, and if you have to talk with Audison US "support" you might as well hit yourself in the head with a brick. This was dirt simple as far as the DA2 Toslink-into-P-DSP was concerned.

Now as far as why, I'm not sure. The original Sony/Philips specification for S/PDIF doesn't define volume control specifically. There are some "words" reserved for some possible volume state data, and perhaps those have been defined in a later version of the specification which I haven't read.

It's also possible that they are doing some transform where they are changing the amplitude of the signal in the digital domain based on some algorithm they have created, which looks at the volume knob state of the HU. If they do that, they are essentially compressing the dynamic range of the digital signal, but that's not a horrible thing, since in a car - especially a moving car - the dynamic range of a CD is useless, and Ken Pohlmann - an early advocate of digital audio - long advocated a "compression" button for CD players for cars for this reason.

But it seems great so far.
Musicar Certified Sound
Musicar Northwest in Portland, Oregon