[Solved] iConnect crackling sound with USB soundcard

[xenoxaos]

Hi,

I have an E-MU 0204 usb soundcard on Iomega Iconnect with ArchLinux 3.1.4-2-ARCH. The card is recognized but the sound is very bad : lot of crackles.

aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
front:CARD=USB,DEV=0
E-MU 0204
Front speakers
surround40:CARD=USB,DEV=0
E-MU 0204
4.0 Surround output to Front and Rear speakers
surround41:CARD=USB,DEV=0
E-MU 0204
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=USB,DEV=0
E-MU 0204
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=USB,DEV=0
E-MU 0204
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=USB,DEV=0
E-MU 0204
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=USB,DEV=0
E-MU 0204
IEC958 (S/PDIF) Digital Audio Output

If I use Pulseaudio, sound is better. I could be satisfied with this, but my player squeezeslave seems using directly Alsa and the sound is very bad.

cat /etc/asound.conf
pcm.!default {
type pulse
}

ctl.!default {
type pulse
}

# Explicit PulseAudio device
pcm.pulse {
type pulse
}

ctl.pulse {
type pulse
}

Can you help me to have good sound with only Alsa, or to force squeezeslave using Pulseaudio ?
Thanks

[minscof]

I found a parameter to have better sound.

I change the default rate in /usr/share/alsa/alsa.conf and restart alsa

Code: Select all

72c72
< defaults.pcm.dmix.rate 44100
---
> defaults.pcm.dmix.rate 48000


With a rate of 44100 sound is really better. I don't understand why this parameter was used in my configuration because i didn't use dmix pcm, i believed it, but I can hear the difference now

I would like to understand my problem, so if someone can help me , thanks a lot.

[kmihelich]

Other people on the forum have noted situations of having to change the ALSA config to get rid of sound artifacting, or to even hear sounds using USB cards. Seems to be a somewhat common practice. Remember, Arch does not auto-configure devices that get plugged in, it's always the user's responsibility to set things up.

PulseAudio is of course preferable in any situation you can use it, since it's designed as the One System to interface multiple usage of sound devices across applications with an API abstracted from the core sound system. If I remember correctly, only one application can tie up ALSA at any given time, whereas pulse can manage and play multiple application accesses (like a chime from your desktop playing at the same time you're listening to an mp3).

[timschuerewegen]

Doubling the alsa dmix period size fixed the crackling audio on my iConnect.

I created

/etc/asound.conf

and added

defaults.dmix."USB-Audio".period_size 2048

[minscof]

I post this message to give the solution I found

I just need to add a file /et/asound.conf with this content

Code: Select all

pcm.!default {
    type plug
    slave.pcm "softvol"
}
pcm.dmixer {
       type dmix
       ipc_key 1024
       slave {
           pcm "hw:0"
           period_time 0
           period_size 4096
           buffer_size 131072
           rate 44100
       }
       bindings {
           0 0
           1 1
       }
}
pcm.dsnooper {
       type dsnoop
       ipc_key 1024
       slave {
           pcm "hw:0"
           channels 2
           period_time 0
           period_size 4096
           buffer_size 131072
           rate 50000
       }
       bindings {
           0 0
           1 1
       }
}
pcm.softvol {
       type softvol
       slave { pcm "dmixer" }
       control {
           name "Master"
           card 0
       }
}
ctl.!default {
    type hw
    card 0
}
ctl.softvol {
    type hw
    card 0
}
ctl.dmixer {
    type hw
    card 0
}


now my sound is good. I use logitech s150 usb speaker (integrated dac)

Minscof