im wondering if there is any general rule to applying high and low pass filters to guitar or bass tracks. it seems to me that 20 hz to 20khz is a bit wide for a guitar track and i think it would kinda take up room for other instruments in a mix. and i know usually its all personal taste but im hoping someone can help point me in the right direction.
is there only a certain range of frequencies a guitar or bass track should take up? are there any vst filters i can use? should i just use an eq and drop the unwanted frequencies down?
any information that anyone may have would be greatly appreciated.
thanks in advance - nic
Not exactly what you asked, but there is a possible reason to filter electric guitar and bass. I actually do it either on the way to the amp or the recorder if I record direct. Magnetic pickups are inductively coupled and the physics of that process is such that pickups produce a sensitivity that rises at 6 dB/octave (from the bottom end up until about the electrical resonance of the pickup/cable system, which is typically in the range of 3K to 7K, above which the response then starts to fall off due to the response of that resonance, which produces a high pass filtering effect (second order) which more than compensates and causes the high end to roll off.
If you want to get a more accurate representation of the sound of the strings, the best way is to use optical pickups. Failing that, you can compensate for the sensitivity rise with a compensating filter (6 dB/octave low pass filter) that gives a flat response below the electrical resonance. Just using that filtered tone ends up a little weak on the high end, which may be OK, but you can also mix a bit of the unfiltered tone back in which gives you more high end.
Rewiring the pickups (and switching to active pickups, if they aren't already) can raise the electrical resonance of the pickup/cable system. If you can get that up to around 15K, you pretty much have the natural tone just by using the low pass filter and don't need to mix the unfiltered tone in any more.
In my mixer, I can get about the right filtering on the way to the recorder by combining an 18 db boost with a shelving eq (about 6dB/octave) on the low end at 40 Hz (for bass, or 80 Hz for guitar) coupled with an 18 db cut from a high frequency shelving eq at about 3K. That gives pretty much a continuous 6 dB/octave slope up to 3K and leaves the high end flat, which sounds about right.
I find this to be a huge help in getting a natural tone on my bass guitar. It has only a single pickup very near the bridge, so it naturally confronts the issue of the pickup sensitivity rise, since there is no bass reinforcement to cover it up by reinforcing lower harmonics. Of course, there is also far less string damping from the pickups, too, which helps increase the sustain.
It's also interesting to hear how much fuller and more natural the bridge pickups sound on an electric guitar when the output has the compensating filter. It makes bridge pickups sound very pleasant and natural, not nasally and whiny. Of course, if you want a nasally and whiny tone, you should skip the filter and go with the voicing of the plain pickup.
Cheers,
Otto
