[sdiy] Looking for cheap lowpass filter algorithm

[Seb Francis]

Antti Huovilainen wrote:
> On Wed, 16 Aug 2006, Seb Francis wrote:
>
>> I could spare enough cycles for 32 multiplies per sample per channel, 
>> but
>
> I should emphasize that those are 32 multiplies at _24 kHz_ 
> samplerate, not 48 kHz! So for each actual ADC/DAC sample you need 
> only 16 multiplies.
>

By this do you mean that the FIR filtering is only done on half the 
48kHz samples and the other half of the samples are simply discarded?
Is this better than using an FIR filter with half the number of taps on 
all the samples?

Seb


P.S. No need to calculate the coefficients for me, Eric has pointed me 
to this useful Java Applet ..
http://www.dsptutor.freeuk.com/remez/RemezFIRFilterDesign.html