[linux-audio-user] USB audio capture line/mic: A/D quality, how set record levels?

Clemens Ladisch clemens at ladisch.de
Thu Aug 28 03:25:12 EDT 2003


Mannr at uwaterloo.ca wrote:
> I am considering getting a USB audio interface.
>
> My goal is to capture audio for making CDs.  I will capture from line level,
> eg., from minidisc or phonograph, and from microphone inputs, eg., for
> recording live shows to a laptop.  It should be completely USB powered for
> maximum flexibility.  Digital I/O would be great, but is not required.
>
> I am not looking for professional quality.  But I would like something pretty
> good, eg., at the level of consumer minidisc recorders.  That is what I am
> using to record now.  I don't need any mixing capability.  Plain capture
> at 44.1kHz/16bit and optionally 48.0kHz would be fine.
>
> I've seen lots of gear, eg., Edirol, M-audio, etc.  But I have several
> questions:
>
> - What is the A/D quality of some of the retail units?
>
>   Retail units:
>     Edirol UA-1A, UA-3D (edirol.com),
>     MAudio Transit (m-audio.com),
>     Soundblaster Extigy, Soundblaster MP3+
>
>   Higher quality?
>     Tascam U-122, Edirol UA-20?, MAudio MicPre,
>
>   Professional level (>500USD)
>     SoundDevices USBPre
>     (http://www.sounddevices.com/products/usbpremaster.htm)

The Soundblasters are consumer/gaming devices. I wouldn't trust them
to have good ADCs.

The other units you mentioned are high quality. I'd guess all of them
are at least as good as your "consumer mididisc recorder".

> - Is the Mic preamp any good?

Yes.

> Ie., as good or better than the one in my consumer minidisc?

Probably. It's hard to make a comparison when you don't tell what unit
you have, or how good it is.  :-)

(and not all of the above units do have a mic preamp)

> - What is the "native" capture mode of these units?
>
>   16bits is OK, but I have heard reports that some, like the Soundblaster,
>   capture at 48 or 96kHz and resample for 44.1kHz.  I am looking
>   for true sampling at 44.1kHz.

Only the Creative units resample AFAIK.

> - How can I control record level on these units?

Depends on the unit.

(The UA-1A doesn't have any controls, neither hardware nor software.
The other usually do have controls.)

>        UA-3D         Y     I/O, Y   I/O, YN  I/O, N   ?(1)    16     Consumer
> (1) claims 32/44.1/48k.  Is this 48k native sample rate?

The website says this is for the digitial I/O, and doesn't mention the
ADC rate. (I guess the ADC can do the same natively; try asking
Edirol.)

> Edirol UA-5          9VDC  I/O, Y   I/O, YY  none     44/48/96(2) 16/24  ???
> (2) "real time sample rate conversion", is this 96k native sample rate?

This too applies to the digital input only. The website says the ADC
can do 44.1.


The M-Audio Transit and MobilePre aren't yet supported by ALSA, and I
don't know about the USBPre.

I would recommend one of the Edirols, but you have to choose what
features you want.


HTH
Clemens





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