audio over USB v. optical - Page 16

turbocad6 · 02-15-2007, 08:38 PM

np, rr supports it through winamp... volume is an issue though.... IDEALLY anything we come up with as a solution should include a volume control after the dac's.... not to complicate this even more, but this is necissay & should be considered in the initial design I guess....

scott_fx · 02-15-2007, 08:48 PM

yeah, that is definately something that shouldn't/can't be overlooked. volume control is a must. is it possible to control it via software w/o involving kmixer? or does this need to be a hardware solution?

Road_Dog · 02-15-2007, 09:19 PM

There are chips that can do volume control using I2C commands. That could possibly lead to the computer adjusting the volume via USB. Let me rummage through my bookmarks.

Here are some DACs/CODECs with 8 to 192kHz Sampling Rate for Stereo Audio
http://www.chipidea.com/website/prod...application=34

Cirrus makes multi-channel DACs/CODECs:
http://www.cirrus.com/en/products/pro/techs/T3.html

Road_Dog

JasonWW · 02-15-2007, 09:19 PM

Speaking of Kmixer, does anyone know if it is still the big nasty in the new Vista or is the sound quality improved?

Back to the main thread. Thank you.

Felix509 · 02-15-2007, 09:34 PM

The AudioStack is completely rebuilt in Vista, no more 'BAD Kernal Mixer' per say.. Supposed to be Much Much better quality.

Vista will also do time alignment and subwoofer Xover out of the box..

Vista Sound explained on the Creative forum..

Vista with Pictures.. YEAH!

Here is a 19 page thread about sound in Vista, with special guest that was Head of the department that developed the audio part of Vista..

VISTA Sound

One main question in the thread was if there would be a way to do 'Bit Perfect' and it was never full answered.. It seems ALL audio goes through the AudioStack, but it is very high quality now.

Road_Dog · 02-15-2007, 09:36 PM

Nice of Vista.

Here is some I2C eye candy (or controllable indicator lights):
http://www.sparkfun.com/commerce/pro...oducts_id=8247
----------------------
Description: The LM4970 is an IC that pulses LED's in time to music! Perfect for your car, a casemod, or anything else that needs to be bright and flashy. The board itself measures a tiny 0.42 x 0.62 inches in size, yet is capable of driving multiple LEDS.

The LM4970 takes in Left+Right, or Mono audio inputs, and has 3 current controlled PWM led drivers; no current limiting resistors needed! The LM4970 is configured via I2C - and initialization is required for any light output.

The board is compatible with our Triple Color LED bars, our SMD triple color LEDs, or any common anode LED setup. It is not compatible with our Triple Color Through-Hole LED.
----------------------

Still looking for that silicon volume control that is not tied to a DAC/CODEC

Road_Dog

durwood · 02-15-2007, 09:41 PM

From what I know kmixer is gone. Windows re-did the whole mixer/audio control to better support the new HD codecs available. I have not played with Vista nor do I intend to do so.

Roaddog- I sent you a rather long email so you can better understand what we are trying to do. The soundcard will do no processing at all. NONE! All EQ, Crossover, Time alignment is done via software (VST effects). You will need a minimum of a Pentium 4/Athlon to do this, although the 64 bit processors or even the dual core are extremely attractive for this. YOu have a rather steep learning curve ahead of you since we have been working on this since October.

durwood · 02-15-2007, 09:47 PM

Quote: Originally Posted by Felix509

Vista will also do time alignment and subwoofer Xover out of the box..

It looks like they only discuss decoding of Dolby Digital/AC3/DTS material though. We are not decoding anything. Straight stereo with up to 4-way crossover. So VISTA is stil not the way to go. Unless I missed it.

durwood · 02-15-2007, 10:06 PM

Quote: Originally Posted by turbocad6

np, rr supports it through winamp... volume is an issue though.... IDEALLY anything we come up with as a solution should include a volume control after the dac's.... not to complicate this even more, but this is necissay & should be considered in the initial design I guess....

Well, i'll tell you the WAV volume control in Winamp works with my Audiotrak Prodigy Hifi with console/allocator, but that's the beauty of Directwire. hehehe
Maybe if you use VAC, it works the same way as the directwire feature.

Ideally, the volume control after the DAC is the best.

RedGTiVR6 · 02-15-2007, 10:14 PM

Quote: Originally Posted by turbocad6

np, rr supports it through winamp... volume is an issue though.... IDEALLY anything we come up with as a solution should include a volume control after the dac's.... not to complicate this even more, but this is necissay & should be considered in the initial design I guess....

it should be. Adjusting audio in analogue is desired.

RedGTiVR6 · 02-15-2007, 10:15 PM

Quote: Originally Posted by scott_fx

yeah, that is definately something that shouldn't/can't be overlooked. volume control is a must. is it possible to control it via software w/o involving kmixer? or does this need to be a hardware solution?

what I have been told, is that if at all possible, volume control should always be done in analoge.

I plan on finding more reasoning behind this this weekend.

RedGTiVR6 · 02-15-2007, 10:17 PM

Quote: Originally Posted by durwood

From what I know kmixer is gone. Windows re-did the whole mixer/audio control to better support the new HD codecs available. I have not played with Vista nor do I intend to do so.

Roaddog- I sent you a rather long email so you can better understand what we are trying to do. The soundcard will do no processing at all. NONE! All EQ, Crossover, Time alignment is done via software (VST effects). You will need a minimum of a Pentium 4/Athlon to do this, although the 64 bit processors or even the dual core are extremely attractive for this. YOu have a rather steep learning curve ahead of you since we have been working on this since October.

I'd recomend spending some time on that Audio Tuning thread to better understand this really.

Road_Dog · 02-15-2007, 10:42 PM

Durwood
My confusion laid with how the output channels were to be used/mapped.

I sent two PM back to you. I appreciate the SQ info. I haven't been to one before, so I guess I am missing some interesting times...

Better look around to see if one is happening here in rain-soaked Oregon.

Did you catch that Hyde's USB Design by Example book has a section on the TUSB3200 chip? However, no code to work with it. Do you have the evaluation board?

Road_Dog

durwood · 02-15-2007, 11:10 PM

I didn't get the PM's. You must be emailing me.

I don't have any eval boards at this time. I also do not have that book. I sent a query to TI asking them about the chip. I have done some coding in my lifetime, but I am extremely slow at it and lost interest rather quickly. That will be a major hurdle to overcome at this point. My guess is that's why the DAC experts are also avoiding multi-channel as well, besides the fact that home audio people look down their noses at car audio people.

JasonWW · 02-16-2007, 12:01 AM

I'm all for you guys making a device to extract the highest quality you can from the PC and all so I will be following this thread. My biggest hurdle right now is that I assume we are talking about using Bit Perfect to this new device and that means no volume control in Windows nor being able to play DVD's or having any other computer sounds. This is why I haven't tried Bit Perfect. Are you guys also going to sacrifice those other sounds for the music?

I'm wondering if maybe Vista with it's apparently better audio without bit perfect may be the way for me to go. Then I would really be on the bandwagon to making such a multiple DAC device.