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Discussion Starter · #1 ·
I have a reciever that has USB inputs that I can use to recieve audio from a PC.

Can I use my USB connection on the PC to send DD5.1 or DTS sound tracks to the reciever for decoding? I understand that I can manualy set the audio playback feature on the PC for USB when it is connected to the reciever but don't know if this would work with applications like Power DVD or Win DVD for digital sound.

I am just finishing a new HTPC and one of options was to choose what type of 'new' sound card but if this is an option I could use the on-board sound and USB for dual purposes.

I did a search but found nothing like this for USB sound output so any ideas or previous attempts could be useful before I hook this baby up.

thanks.
 

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This sounds like a very interesting feature. I am surprised it hasn't got more "airtime", especially if it actually works.


Does JVC provide any drivers/software for the PC? Obviously you have to have something on the PC side to tell it to output audio to the USB port.
 

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Discussion Starter · #7 ·
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Does JVC provide any drivers/software for the PC? Obviously you have to have something on the PC side to tell it to output audio to the USB port.
The PC recognizes the reciever as a standard USB audio device when it is connected (no special drivers needed.) Then it is just a matter of changing your setting in the control panel under sounds and multimedia for the correct playback device.


It is not advertised for HT usage probably because you have to still send the video signal to a connection on the projector/display instead of using the reciever as the 'switch' But they do mention in their literature that it provides a direct digital connection for PC music, etc... and with the launch of some of these new external USB audio decoders I thought it was worth a try.
 

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Discussion Starter · #9 ·
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Does it give the option for Dolby Digital/DTS output or just 2 channel PCM?
That's the magic question and one I will find out this weekend. The documentation on this feature is so sparse it reads like a 'New computer checklist' (plug this in here, turn this on there, etc..)

Just have to wait a few days so I can finish this DeskTopX / X10 automation stuff.
 

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"and with the launch of some of these new external USB audio

decoders I thought it was worth a try."


Do these new decoders fit in between pc and amp to decode 5.1, 6.1, etc. Hadn't heard of them 'til now.


Randy D
 

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I will be very surprised if you can get DD or DTS passthrough to USB. None of the other USB audio devices do, including the extigy.


There is only a device sold by Asus outside the US that can passthrough DD or DTS but it only works with WinDVD.
 

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I've seen a USB dongle device down at MARS that had coax and optical digital out. I think it was actually an M-Audio product, but I'm not certain. Perhaps that could serve the same purpose?


Kensai
 

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The first things to find out about the receiver is what are the OS requirements and what software does it come with.


There is a standard USB Audio Device Class and it is supported on Win98 & up without installing any drivers.


They could have implemented that or they may have come up with a custom class that requires a driver but allows them to send anything they want.


The standard class supports three classes of audio formats

I is PCM, PCM8, IEEE_FLOAT, ALAW or MULAW.


{note that when I say the class supports I mean a device could support such a feature, not that it must}


II is MPEG or AC-3


For PCM, the number of bits per sample and number of channels are defined in byte-wide fields (so up to 255 bits or channels are theoretically possible). Full-speed (12MHz) USB's maximum is one 1023 byte isochronous packet per millisecond frame or about 8 megabits/sec and 6 channels of 24 bit PCM are only 6.9 mbit/sec. High-speed USB (480MHz) has enough for a whole recording studio.


For MPEG, layers I, II and III in stereo and multichannel are supported.


AC-3 is pretty much AC-3 with optional things like control over dynamic range scaling.


Notice anything missing? Yep, DTS.


Yet Edirol's UA-1D USB SPDIF interface (I just bought the analog 1A & like it), claims support for Dolby Digital and DTS encoded audio with the included WinDVD. My guess is that either they've created a custom class or the market dept. is having fun with us and "support" means WinDVD decodes & sends stereo PCM over the SPDIF.


--


In short, it's possible to do multichannel audio over USB, but whether any particular receiver does will take research on that particular model and given the Edirol example, skepticism. Don't buy any of this stuff without a generous return policy.

http://www.edirol.com/products/info/ua1d.html

http://www.usb.org/developers/devclass_docs.html
 

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Discussion Starter · #14 ·
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, but whether any particular receiver does will take research on that particular model
I am in mucho agreement with this. (would be nice if the documentation just said so)

I did not buy the reciever with this in mind. It is just something I wanted to try.
morganw:

Thanks for the extended class info on USB audio very informative and if it doesn't work I will now know why.


Back to work now... I have a 'Star Wars' movie to see tonight. :D
 

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Quote:
Originally posted by Alric
I will be very surprised if you can get DD or DTS passthrough to USB. None of the other USB audio devices do, including the extigy.
Huh? The Extigy connects via USB so it has to get DD information that way. I've read reviews where PowerDVD was used to play DVD's and pass DD 5.1 to the Extigy.


Maybe I'm missing something. :) I sure hope not because I'm about to get an awesome IBM ThinkPad and I was looking forward to using the Extigy.
 

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In other threads in this forum that discuss the Extigy people were not able to get DD or DTS. They could get PCM only.


I don't remember what player they used but I remember the people that bought it concluding it was useless for HT use.
 

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I always found the Extigy intriguing because of this quote:


"Provides mixing of Dolby Digital audio with the real-time gameplay audio effects - a feature that a normal consumer Dolby Digital A/V receiver is not capable of supporting Advanced USB Features".


However, there is no DTS support and DD decoding only works with PowerDVD and WinDVD.
 

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Quote:
Originally posted by Alric
In other threads in this forum that discuss the Extigy people were not able to get DD or DTS. They could get PCM only.


I don't remember what player they used but I remember the people that bought it concluding it was useless for HT use.
DOH! My bad. I see what you are saying now... The Extigy does the DD decoding. So, if you have a receiver that can handle the 6 analog inputs you should still be OK... Probably not the best situation, but it doesn't look like a bad deal for a huge audio upgrade on notebooks. :)
 

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Quote:
Originally posted by Alric
I found the quote:


"DVD Movies Dazzle

We tested the Dolby Digital decoding with a Star Wars Episode 1 DVD. We could get only plain vanilla stereo but after a call to Creative, we were told that the PowerDVD playback software had to be set to pass-thru audio to the SPDIF port--an unintuitive option but we guess strange things have to be done to pass audio through the USB port. Anyway these settings are covered in the guide program, which we had overlooked.

...

I wonder if they fixed it later!! Neat. I always found the Extigy intriguing because of this quote:

I doubt it. We're talking about having the Extigy pass the DD signal thru to a receiver so that the receiver does the decoding. They really don't mention this at all. My guess is that they were still relying on the Extigy to do the decoding with a powered 5.1 speaker setup connected directly to the unit.


In any case, I'm going to try one out to see if it's worth the money. I'll post more on this unit soon. :)
 
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