ok
i am doing the sound design for a film and there is a scene in which the protagonist plays back a seriesof sounds on a handheld microcassette recorder. my idea was to make it more authentic by reducing the quality to mimic the tiny speaker. how do i best do this? would reducing the bit rate work? or do i need to choke the sound in some other way? any feedback is much appreciated

Basically, you can be satisfied with a compressor and a 3/4-band EQ. Try reducing the dynamic with the comp first, and then limit the frequency bandwdth with 2 cut filters (low-pass & high-pass) and increasing the high-med frequencies. How does it sound?
You can even add a low distortion process, and mix the result with a real "tape hiss" to add some realism.

Or even really record with a mini-tape magneto & re-record the playback? Just experiment ;-)

If you want a more numerical/robot effect, you'll need to under-quantify your audio source (ie convert it from 24bit/48kHz to 8bit/11,05kHz). Any audio utility can do that.
There is also Lo-Fi, a VST & AudioSuite plugin which automatically do that.

Have fun, bye.

thanks yuk, that is a huge help. i think i'll play with the compression and eq, maybe some preamp vst for the bit of distortion. i dont need the numeric/robotics of the under-qualifying, but thats a useful bit of knowledge to file away for the future. thanks a ton for your help

personally I would just mic a microcassette player. if you really want the realism.

Yeah, a compressor and band or hi-pass should give a good result.

what about wet delay with lfo to delay time for some wow n flutter...