LowPass Filter

Yes a 6db per octave basic filter. Try using different topologies like an active filter or a gyrator active or passive or an inductor you will get better control over the Q . I published a graphic equalisor using Gyrator elements pinch one of the transistor elements and replace your capacitors with it and stick a pot in in line with it and you will have an adjustable filter.

Ok, thanks.

My comment was meant read '' A NICE 6db PER OCTAVE FILTER '' it sounds unintentionally harsh as is..The reason 6db filters are not ideal for most circuits is in order to get a good amount of attenuation you need to start the filter very much lower or higher than the intended cutoff frequency depending on whether it's a high pass or low pass filter. But with the addition of a choke you get 12db per octave or 18db or almost any amount with a gyrator. Which means you can keep more of the signal you want and less of the ones you don't.

Should I use a butterworth or chebyshev filter?

Ether really as both are the fundamental building blocks of just about any filter design including DSP . However my personal choice would be butterworth as it has slightly better characteristics for audio. For example it has less ripples in the pass band but The number of poles in Butterworth filter is more compared to that of the Chebyshev filter of same specifications, this means that the order of Butterworth filter is more than that of a Chebyshev filter. This fact can be used for practical implementation, since the number of components required to construct a filter of same specification can be reduced significantly. So stick your hand in the hat and pull one out as unless you have very stringent specification which may suit one or the other it's not really worth considering their merits it's just you can get used to designing a particular one and tend to stick with it.

Ok, i'll try more complex filters. I Didn't know gyrator filter, thanks :D