Audio from USB choppy

Audio codec and audio ports
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anders@lobger.dk
Posts: 3
Joined: Mon Apr 20, 2009 7:22 pm

Audio from USB choppy

Post by anders@lobger.dk »

Hello all,

In Windows 7 Home Premium when playing music from iTunes through USB there are a lot of drop-outs.

I have a Cyrus 8 integrated amp with USB in. Cyrus specifies the bitrate must be 16Kbit.

I have a large buffer in iTunes and around 65% physical memory allocated.

What actually comes out of the USB Audio port - is it an analogue or digital signal?

Any musings and deliberations are greatly appreciated, thanks.

Best regards,
Anders

fly
Posts: 162
Joined: Thu Jul 22, 2010 2:02 pm

Re: Audio from USB choppy

Post by fly »

In Windows 7 Home Premium when playing music from iTunes through USB there are a lot of drop-outs.
Does it work when playing local audio files with a different player?
What actually comes out of the USB Audio port - is it an analogue or digital signal?
That depends on the hardware USB-Audio adapters are separate soundcards and thus completely out of CompuLabs scope. If the vendor choose to output digital sound it's up to them. Creative has some adapters with SPDIF, but the majority just provide simple stereo out and mic in.

anders@lobger.dk
Posts: 3
Joined: Mon Apr 20, 2009 7:22 pm

Re: Audio from USB choppy

Post by anders@lobger.dk »

Thanks for your suggestions. I tried with Windows Media Player, but with the same choppiness in the output.

I have no idea whether the USB signal goes to the DAC in the amp or straight to the pre-amp. There's no third-party USB-adapter. I connect the fit-PC2 and the amp with a quite ordinary USB cable - well capable of 16Kbit. Obviously there's an adapter in the amp, but what exactly it does, I don't know. I use the Microsoft USB-audio driver.

Cheers,
Anders

Ryelands
Posts: 18
Joined: Sun Aug 16, 2009 9:42 am

Re: Audio from USB choppy

Post by Ryelands »

I had similar issues with a USB DAC - it might be worth your trying the following BIOS settings:

Advanced Menu > Boot-time Diagnostic Screen: Disabled

Intel Menu > CPU Control sub menu > Hyperthreading: Enabled; Processor Full Speed: Disabled

Intel Menu > Chipset Control sub-menu > Audio, SDIO and LAN PXE BOOT: Disabled

Intel Menu > Video (Intel IGD) Control sub-menu > Graphic Memory Aperture Size: 128MB.

as it only takes a moment to do. For more details, see:

http://www.cicsmemoryplayer.com/index.p ... P.Headless

HTH

Dave

fly
Posts: 162
Joined: Thu Jul 22, 2010 2:02 pm

Re: Audio from USB choppy

Post by fly »

I have no idea whether the USB signal goes to the DAC in the amp or straight to the pre-amp. There's no third-party USB-adapter. I connect the fit-PC2 and the amp with a quite ordinary USB cable - well capable of 16Kbit. Obviously there's an adapter in the amp, but what exactly it does, I don't know. I use the Microsoft USB-audio driver.
The Cyrus 8 IS your third-party usb audio adapter. USB-Audio profile is declared in the USB standard, so any deriver conforming to that should do. If Cyrus provides special drivers you should drop the generic Windows driver and use the Cyrus one. What the adapter exactly does, is up to Cyrus. I checked their website, but because they force me to register, I can't have a look at their manuals. In general you could have a look at this circuitry [1]. USB specs are available at USB IF [2].

However, you might be better of just trying the steps from above. Have you tried the USB cable and Cyrus with an other PC? Have you replaced the cable just to make sure? I myself had once a similar problems with my USB-Bluetooth-Audio transmitter. I spent quiet some time trying to fix bluetooth before I realized the USB cable was crap...


[1] http://www.pavouk.org/hw/usbdac/en_index.html
[2] http://www.usb.org/developers/docs/

anders@lobger.dk
Posts: 3
Joined: Mon Apr 20, 2009 7:22 pm

Re: Audio from USB choppy

Post by anders@lobger.dk »

Cheers guys,

And thanks for the effort, much appreciated.

I tried the BIOS settings and it was a vast improvement, but there are still perceptible quality issues. looking at your link to cics, it's clear that it can be done to near perfection, but this requires a lot more dedication on both my and the fit-PC's parts :)

For now I'll leave music and radio to my SqueezeBox, TV and video to the fit-PC2 and put a fit-PC2i on my christmas list.

Oh, and yes, I tried the cable before posting. Sometimes such trivialities can make for hair-pulling experiences followed by colouring of the cheeks :D

Regards to all,
Anders

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