Sound system developement question

[Ian Smith]

On Sat, 15 Sep 2012 14:53:41 +0200, Hans Petter Selasky wrote:

 > There are some sysctls which tell how oversampling is done:
 > 
 > hw.snd.feeder_rate_quality

Hans and all,

That's good to know, so I checked mine (default):

hw.snd.feeder_rate_quality: 1
hw.snd.feeder_rate_quality: sample rate converter quality (0=low .. 4=high)

and so set it to 4.  I'm just listening to a ~192kbps VBR MP3 radio 
stream, and hear no perceptible difference (probably not surprising), 
nor does top show any apparent difference in cpu or interrupt rates:

last pid:  2172;  load averages:  0.16,  0.25,  0.21   up 12+19:41:12 19:54:06
150 processes: 2 running, 132 sleeping, 16 waiting
CPU: 14.0% user,  0.0% nice,  5.3% system,  7.8% interrupt, 72.9% idle
Mem: 292M Active, 243M Inact, 161M Wired, 25M Cache, 85M Buf, 17M Free
Swap: 2048M Total, 170M Used, 1877M Free, 8% Inuse

  PID USERNAME    THR PRI NICE   SIZE    RES STATE    TIME   WCPU COMMAND
   11 root          1 171 ki31     0K     8K RUN     43.2H 90.97% idle
 1740 smithi        1  46    0   203M   143M select 509:57  3.56% Xorg
 1852 smithi        1  50    0 35756K 10544K select 310:36  2.88% gkrellm
16115 smithi        5  59    0   298M   211M ucond  153:18  1.37% seamonkey-bin
   12 root         16 -60    -     0K   128K WAIT    96:09  1.37% intr
 1844 smithi        6  44    0 18812K  7064K select 230:56  0.10% xmms

.. via xmms, on an 1133MHz P3-M running at 733MHz, 8.2-RELEASE i386.

Need I reset the sound system to have that take effect?  If so, how?

cheers, Ian