zappfinger
Posts: 34
Joined: Tue Nov 26, 2013 7:25 pm

Scarlett 2i2 audio in troubles

Mon Apr 27, 2015 9:39 am

Hi,

I am using the Pi model 2 headless with Csound and a USB sound setup.
Had no problem with a cheap C-Media USB card, but with my Scarlett 2i2 the input sound is terrible (noisy, weak etc)
I must say I do not use a powered USB hub, but I do have a 2A power supply and even a small midi keyboard attached via USB. The problem also exists if I disconnect the midi device.
Output sound is no problem here!
Only when I use input, like

Code: Select all

arecord | aplay |
I get the very bad sound.
Tried all available tricks (I think), but no luck yet.

Any ideas?
Richard

User avatar
cyrano
Posts: 714
Joined: Wed Dec 05, 2012 11:48 pm
Location: Belgium

Re: Scarlett 2i2 audio in troubles

Wed Apr 29, 2015 7:55 pm

I hope the Focusrite has an external power supply. It really needs a full 500 mA on the USB bus. Using it with an external power supply seems better for the audio too...

zappfinger
Posts: 34
Joined: Tue Nov 26, 2013 7:25 pm

Re: Scarlett 2i2 audio in troubles

Thu Apr 30, 2015 8:37 pm

cyrano wrote:I hope the Focusrite has an external power supply. It really needs a full 500 mA on the USB bus. Using it with an external power supply seems better for the audio too...
Yes, maybe I should try a powered hub... The strange thing is, that the output signal is Ok, but the input not.

Sleep Mode zZ
Posts: 319
Joined: Sun Aug 19, 2012 5:56 am
Location: Finland

Re: Scarlett 2i2 audio in troubles

Thu Apr 30, 2015 8:50 pm

Do you have the max_usb_current=1 set in your config.txt?

viewtopic.php?f=29&t=100244

zappfinger
Posts: 34
Joined: Tue Nov 26, 2013 7:25 pm

Re: Scarlett 2i2 audio in troubles

Thu Apr 30, 2015 9:25 pm

Sleep Mode zZ wrote:Do you have the max_usb_current=1 set in your config.txt?

viewtopic.php?f=29&t=100244
I tried it just now with my guitar plugged in.
At first it had no effect, when I tried:
arecord | aplay
which uses the low sampling rate of 8000 Hz

But when I tried with:
arecord -f S32_LE -r 60000 -D hw:0,0 -d 2 -c 2 | aplay
Recording WAVE 'stdin' : Signed 32 bit Little Endian, Rate 60000 Hz, Stereo
Warning: rate is not accurate (requested = 60000Hz, got = 48000Hz)
please, try the plug plugin
Playing WAVE 'stdin' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo
The first few seconds there was no improvement, but then it worked!!!
Yes, thanks very much!

So in this case it is a combination of using max-usb-current=1 AND a decent samping rate (48000 Hz)

zappfinger
Posts: 34
Joined: Tue Nov 26, 2013 7:25 pm

Re: Scarlett 2i2 audio in troubles

Fri May 01, 2015 7:41 am

It seems I spoke to soon.
The clean signal I was hearing after a few seconds was just the monitor output from the 2i2.

So, back to the drawing board....

Sleep Mode zZ
Posts: 319
Joined: Sun Aug 19, 2012 5:56 am
Location: Finland

Re: Scarlett 2i2 audio in troubles

Fri May 01, 2015 9:22 am

It does not seem like it is about power then.

Maybe the problem is simultaneous recording and playback (full-duplex)? Have you recorded to a file without playing anything out at the same time - does the file sound bad?

zappfinger
Posts: 34
Joined: Tue Nov 26, 2013 7:25 pm

Re: Scarlett 2i2 audio in troubles

Fri May 01, 2015 9:49 am

Good idea, just tried it, same result unfortunately when I play back the .wav...

Return to “Troubleshooting”