audio over USB v. optical - Page 3

Dennis5587 · 02-06-2007, 10:14 PM

holy ****, if this gets done, I'm in...

Five 8V outputs from a computer?.. in shock

scott_fx · 02-06-2007, 10:22 PM

you guys wouldn't entertain the notion of going with balanced outputs would you? :-(

turbocad6 · 02-06-2007, 10:27 PM

Quote: Originally Posted by crabbdaddy

turbo... im not sure of your need for multiple outputs. if its for 5.1 or mutliple channel audio source.. then seems you would have to decode that material which then leaves the DAC out of the picture correct? if its not for multilpe channel source material... then wouldnt the amp passthru work.. as on the alpine amps?

right now I have no problem with just stereo...

although I usually don't run any rear speakers at all, I am considering a component set foir the rear doors in my new build, as it's a 4 door car...

if I have the 4 speakers in place, then having the option of running a phantom center channel on some dolby stuff & running surround ain't a bad thing really, like I do with my alpine now, are you saying this can't be done with a usb dac? I thought I'd be able to decode it on the pc & then just send it to the dac's for just the d/a conversion?

I'm not sure what you mean about amp pass thru's... my goal is a seperate channel for each driver, 2 way front stage, 2 way rear's & a sub.... I almost never run subs stereo, but this car is probably getting only one sub anyway...

turbocad6 · 02-06-2007, 10:28 PM

scott, what would balanced outputs do to this equation?

scott_fx · 02-06-2007, 11:36 PM

could you elaborate on that question? are you asking what the benefits would be or how it would complicate things? just for those that don't know, a balance signal can always be run as an unbalanced by grounding the -signal to the shield so it wont limit anyone

turbocad6 · 02-07-2007, 12:12 AM

nevermind, I read your intent on that statement wrong, I now realize you were asking that cause you want balanced, a lot of the pro stuff out there uses balanced... it would be nice if my mcintosh's could make good use of a balanced signal though...

I would be interested in developing something new here, but also think it may be much easier to just adapt an existing solution, maybe worse case modifying an existing piece maybe.... without most being able to take advantage of a balanced signal I think a higher output voltage would be cool.... this seems to be another big drawback with currently available equiptment, balanced line outs are available, but useless to most, but higher output voltages are almost non existant in pc audio....

crabbdaddy · 02-07-2007, 04:46 AM

Quote: Originally Posted by turbocad6

right now I have no problem with just stereo...

although I usually don't run any rear speakers at all, I am considering a component set foir the rear doors in my new build, as it's a 4 door car...

if I have the 4 speakers in place, then having the option of running a phantom center channel on some dolby stuff & running surround ain't a bad thing really, like I do with my alpine now, are you saying this can't be done with a usb dac? I thought I'd be able to decode it on the pc & then just send it to the dac's for just the d/a conversion?

I'm not sure what you mean about amp pass thru's... my goal is a seperate channel for each driver, 2 way front stage, 2 way rear's & a sub.... I almost never run subs stereo, but this car is probably getting only one sub anyway...

nope im not saying it cant be done .... i read another thread that stated depending on the DAC that its sampled different for DVD . but i may have confused / misunderstood the thread. ill go back and find the thread. lots of info out there sometimes its hard to decipher.

i thought the alpine amps have a passthru feature that allows the signal from amp a to pass thru via cable to amp b to reduce cables needed to run multiple amps.

i dont think im adding any value to this thread... ill go back and study more..

durwood · 02-07-2007, 07:23 AM

Five 8v outs is not enough IMO (not talking about 5.1 here). I think we need at least eight 8V low impedance outs, if not 10, Good to have a few extra. 8 or 7 would be the best route for people running a 4-way setup as myself.

I agree with Turbo on the balanced out situation. High ouput voltage is hard to come by since most home audio/professional gear does not require it, but the car needs it. Balanced out would be a secondary option, although if it's that easy to bypass it and doesn't add a huge additional cost maybe it should be included.

durwood · 02-07-2007, 07:25 AM

Thinking about it some more, it really shouldn't be that hard to string multiple DACs together in stereo mode to get additional channels.

RedGTiVR6 · 02-07-2007, 07:29 AM

Quote: Originally Posted by proph

Hey Red,
Saer will chime in in a sec. He helped me bump the Silverstone DAC from 1v RMS to 3.5vRMS. He's local just so you know, this is exactly what I was talking about at the meet. I'm glad someone else sees the potential.

this is something I've been thinking of for some time now and a few comments by some others has encouraged me to try and persue it...

I didn't really mention it at the meet because very few people (in the grand scheme of things) are concerned with this level of sound.

If there are people from the meet that want to work on this, send them to this thread!

Quote: Originally Posted by crabbdaddy

but whether its doable in a cost effective manner either usb or PCI is another story.

see, that's the thing. I'm not so interested in doing this for the folks that are overly concerned with saving a buck. This is something for those of us who are in persute of good sound and are willing to go a bit above and beyond.

Quote:

maybe build along the lines of turbo's thinking.. a pc for data and frontend and a separate unit (pc case etc) connected via usb with just a powersupply and DAC's with analog output.

That's been the intent all along. It wouldn't be a PC case, it would be just like an outboard sound card, on 12v DC power, with multiple higher voltage RCA outs, and user replaceable parts.

Quote:

turbo... im not sure of your need for multiple outputs. if its for 5.1 or mutliple channel audio source.. then seems you would have to decode that material which then leaves the DAC out of the picture correct? if its not for multilpe channel source material... then wouldnt the amp passthru work.. as on the alpine amps?

This initial product will not be 5.1. It will just be multiple output. Remember guys, K.I.S.S. at this point, K.I.S.S.!!!

Quote: Originally Posted by proph

So whats your goal here Red? Five 8v output, 1 input? I know others might have something different in mind.

For starters, I'm thinking 5 high voltage outputs. Not necessarially 8v, all depends on the design. I'd want at least 4v.

This would cover the following scenereo:

1 output for Tweeters
1 output for mid-range
1 output for mid-bass
1 output for rears (for those who use them)
1 output for sub-bass

This initial set-up would cover the most users I would think.

1 input for right now, since if you had multiple inputs for audio, they would go throughthe computer then out to this piece.

Quote: Originally Posted by scott_fx

you guys wouldn't entertain the notion of going with balanced outputs would you? :-(

at this point, I don't think it makes the most sense...remember, K.I.S.S.!

Once we get it all done, then we can start looking at other options. For now, let's just worry about getting a working unit!

Quote: Originally Posted by durwood

Five 8v outs is not enough IMO (not talking about 5.1 here). I think we need at least eight 8V low impedance outs, if not 10, Good to have a few extra. 8 or 7 would be the best route for people running a 4-way setup as myself.

Once we get down to actually making the unit, we can determine the number of outputs.

Right now we need to figure out how to go about making this thing first.

Quote:

I agree with Turbo on the balanced out situation. High ouput voltage is hard to come by since most home audio/professional gear does not require it, but the car needs it. Balanced out would be a secondary option, although if it's that easy to bypass it and doesn't add a huge additional cost maybe it should be included.

agreed.

RedGTiVR6 · 02-07-2007, 07:50 AM

guys - I think that all of the interest in this is great! I just want everyone to remember, that talking and walking are two different things.

We now have a list of desired features:

USB connection to the PC
5 pair of RCA outputs
- at least 4V outputs, prefered to have 8V
- socketed RCA sockets - so that the end user can opt to upgrade the sockets if desired
User replaceable OpAmps
- User replaceable caps would be nice, but not necessary
12v DC power supply
Encased in an external enclosure - much like a DAC or an external sound card
Size is of concern, we need it to be small enough that it's easily able to be hidden. Nothing like the size of the DBX drive rack and the like. Something along the same size as the Alpine 701 brain.

with this we can now start to look at building a prototype. I've contacted Douglas and asked him to take a look at this thread and if he wanted to register to give us some input. We'll see. Else I've got a few other contacts I can go after.

durwood · 02-07-2007, 07:51 AM

Quote: Originally Posted by RedGTiVR6

1 output for Tweeters
1 output for mid-range
1 output for mid-bass
1 output for rears (for those who use them)
1 output for sub-bass

Ok well that works. When I was refering to 8 channels I was counting Left and Right channels separately. I am willing to blow the dust of my EE books and get my hands dirty with some design for this. Beware though, I am really rusty. I think I could help with some of the analog stuff.

Or were you contracting/contacting some outside sources?

RedGTiVR6 · 02-07-2007, 08:03 AM

Quote: Originally Posted by durwood

Ok well that works. When I was refering to 8 channels I was counting Left and Right channels separately. I am willing to blow the dust of my EE books and get my hands dirty with some design for this. Beware though, I am really rusty. I think I could help with some of the analog stuff.

Or were you contracting/contacting some outside sources?

either or.

If some users want to tackle this...go for it!

durwood · 02-07-2007, 08:11 AM

hahaha I can definitely help or assist on the output section, but the rest is above what I know. I wish I knew more about PS but that wasn't my strong area.

The software part will probably be one of the most difficult things about this.

turbocad6 · 02-07-2007, 08:21 AM

see, now I thought the software end was cool, I mean with console & vst pluggins what else do we need software wise? I thought it'd be really hard to find x overs, 31 or more band eq's & phase shift software, but I thought that was covered at this point? also, I thought routing was doable easily enough too... what's the difficult part of the software?