Re: [LAU] Intel-hda jack low latency howto

From: Matthew Smith <matt@email-addr-hidden>
Date: Mon Nov 03 2008 - 10:36:49 EET

Quoth Arnold Krille at 2008-11-03 18:57...
> One of the design decisions of the hda is to support 48 kHz for DVD. And to
> make it simple they only support 48kHz in hardware. While you can open the
> device with lower samplingrates this will get resampled to 48kHz either by
> the driver or the chip. And as you don't know what quality that resampling
> algorithm has (remember the only thing "high" in the hda is the name), you
> will want to use 48kHz from start to end and only downsample to 41kHz
> directly before creating the cd master. Which has the advantage that you can
> use the fine libsamplerate instead...

Interesting. I wonder, does it explain this?

Whilst I use fully external ADC/DACs for music use, with the HDA card
disabled, for everyday use - which means Skype since I don't do any
other sort of everyday audio - I use a Zoom H2 as my microphone/input
sound card and have headphones plugged into the on-board HDA.

If I have the H2 set to sample at its default of 44.1ksps, playing back
my voice on a Skype test call, I sound like someone who should be
guarding a hareem ;-) Setting the H2 to sample at 48ksps, I sound my
<cough/> "normal" self.

Would it just be at the receiving end of the loop that my voice is
pitch-shifting, or is there some funny re-sampling going on in the Skype
software?

I'm just so glad that I tested the sound before calling a client!

Cheers

M

-- 
Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
Business: http://www.smiffytech.com/
Personal: http://www.smiffysplace.com/
LinkedIn: http://www.linkedin.com/in/smiffy
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Received on Mon Nov 3 12:15:01 2008

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