Sound Blaster USB?

Kazuhito HONDA kazuhito at
Sat Feb 17 12:08:59 UTC 2007

From: "M. Warner Losh" <imp at>
Subject: Sound Blaster USB?
Date: Fri, 16 Feb 2007 15:13:21 -0700 (MST)

> I have a sound blaster usb that I just bought.  When I connect it to
> my computer I get the following:
> uaudio0: <Creative Technology SB Live! 24-bit External, class 0/0, rev 1.10/1.00, addr 2> on uhub0
> uaudio0: audio rev 1.00
> pcm0: <USB Audio> on uaudio0
> When I'm playing music with xmms2d, I get no sounds out the head-phone
> portion of this device.  However, xmmd status claims the music is
> playing.  Here's all the status info I could find.

At first, the head-phone is plugged in `phones' 
before sound blaster usb is connected to your computer.
Then, you connect your sound blaster to your computer.
After that, you must not unplug the head-phone 
and not push `MASTER (PUSH-MUTE)' knob  on usb device.
You can get some sounds, probably.

Its cause is that FreeBSD sound system is unfit for USB sound systems.
Some USB sound devices have several mute knobs.
But FreeBSD sound system has one mute knob only.
Thus FreeBSD can't control mute knobs of USB sound devices.

`SB Live! 24-bit External' makes the mute knob on 
when none is plugged in `phones'.
FreeBSD can't change the mute knob from on to off.
Thus you can't get any sound.
If something is plugged from beginning,
the mute knob is off, and you can get some sounds.

`MASTER (PUSH-MUTE)'knob can change the mute status to on,
but it can't change the mute status from on to off.

At least, my `SB Live! 24-bit External' does that behaviors.

your sincerely,
Kazuhito HONDA

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