[LAD] audio recording through pipe using mplayer and sox sometimes has incorrect speed

Hi all, I am using mplayer, sox and tee to capture streaming internet radio and send it both to an audio recognition program and to a file (recording). This is how I do it: mplayer -playlist {url} -nocache -af volnorm -msglevel all=1 -nolirc -vc dummy -vo null -ao pcm:file={$fifo1} & sox -S {$fifo1} -c 1 -r 8000 -t wav - resample | tee {$recording} | tee {$fifo2} & ...... $fifo1 and $fifo2 are named pipes, $fifo2 is processed by an audio recognition program. The idea is that the audio is converted to low quality wav (8000Hz mono) after which it is fed to the program and simultaneously recorded. This works great most of the time but sometimes the recording is too long/slow or too short/fast. Sometimes the speed is slighly wrong and sometimes it is terribly wrong. When the speed is too slow, I notice that the file is also much larger and if I open the file in Audacity, the program tells me that the duration of the recording is for example two hours in stead of 1 hour (when the speed is twice as slow as it should be). Below is a list of three recordings that are the product of this setup. The middle one is larger and when I play it back it is three times too slow. 55M 2009-04-09 07:00 /data/station_recordings/48_20090409-0600.wav 152M 2009-04-09 06:00 /data/station_recordings/48_20090409-0500.wav 55M 2009-04-09 05:00 /data/station_recordings/48_20090409-0400.wav My guess is that it has something to do with the sample rate. If anyone has any idea where this goes wrong or what I could do to try to fix it, please let me know. Arnold.