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jbeale
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good quality USB audio mic input ?

Tue Sep 05, 2017 2:24 pm

Does there exist an inexpensive USB audio interface that works on the R-Pi with a good quality mic-level input?
I have a no-name usb-audio dongle from ebay, super cheap at $5 but has a rather noisy and distorted input.

I've seen >$100 add-on board solutions using I2S which are I assume good. Is there anything in between?
Has anyone measured the DNR (dynamic range) of these audio parts?

Basically I'm looking for the cheapest thing that can give me a DNR of 70 dB or more on a microphone-level input.
Only one channel needed, not stereo. I do not need any kind of audio output.
I only need a low sample rate, for example 8 kHz or 16 kHz is fine.

It should be possible because the very cheap PS3 Eye camera has good quality audio (and 4 channels!) from its built-in mics, but it's a little bulky and I'd have to hack into it to connect my external mic-level signal.

Note: by "mic level" I'm thinking the full-scale signal would be about -50 dBV or 3 mV (rms).
So the input-referred noise should be 70 dB down from that, or 1 microvolt rms over a 4 kHz bandwidth.

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topguy
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Location: Trondheim, Norway

Re: good quality USB audio mic input ?

Tue Sep 05, 2017 5:32 pm


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jbeale
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Re: good quality USB audio mic input ?

Tue Sep 05, 2017 5:38 pm

Thanks for that link. Indeed, that saying is often true. I mentioned the PS3 Eye as a striking counterexample, because it has good audio quality for $7 shipped: https://www.amazon.com/Sony-PlayStation ... B0072I2240

I was curious if anyone knew of a similar deal on something that had external audio in, instead of internal mics only. Or if there's any page out there with actual SNR, DNR measurements on low-end audio hardware, like for example
http://www.bealecorner.org/best/measure ... ic-L45.htm

(...and actually, in the world of audio gear in particular, I have found you may get quite a bit less than you pay for)

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topguy
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Re: good quality USB audio mic input ?

Tue Sep 05, 2017 11:44 pm

I reread your post and realised that you had asked for audio input. So I thought I had deleted this answer.

There are also a lot of external audiocards of different quality and features. But the ones that has reasonable production volume will be with both input and output and definitely stereo. And do they comply to your DNR standards ? Good question, not sure you will find that on any datasheet and very few people have the equipment/knowledge to measure it.

Neil_Hines
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Joined: Fri Sep 29, 2017 11:51 am

Re: good quality USB audio mic input ?

Tue Oct 03, 2017 11:50 am

topguy wrote:
Tue Sep 05, 2017 5:32 pm
You get what you pay for:
http://www.bestproducts.com/tech/gadget ... pc-or-mac/
Wow, Thanks for sharing I didn't know about it USB audio Mic input. Thanks for sharing the link. :)

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