On-board notch filter?

[CosmoReverb]

Hey there. Does anyone know of any commercially available on-board preamps with a tone shaping section that consists of a two-band eq and a notch filter with boost/cut and freq sweep capabilities?

I was toying with the idea of a chambered fretless with piezos and it seems like an on-board pre with those capacities would be a cool choice but I couldn't find any in my initial web search.

[ctmullins]

Umm - how is that different from a traditional three-band EQ with sweepable mids (like the EMG BQC)?

[CosmoReverb]

As I understand it, the width and falloff of the effected frequencies. Notch filters effect a narrower band and have a much steeper falloff. At least that's my impression of how it works but I certainly could be wrong.

[J.Wolf]

two words: Empress para EQ

There are several onboards with powerful sweepable mids, but the set Q on any of them is likely to be limiting in certain settings. Since I bought the Para EQ, I'm able to zero in on and kill offending frequencies super easily, plus it has plenty of super clean gain. That thing is solid gold, especially for notching. Upright and hollowbody players should especially take note.

[ddnidd1]

Notch filters, because they have such a narrow Q, are typically only used to cut an offending frequency. They're not normally used for boost.

Feedback suppression in a PA would be a prime example of the application of a notch filter.

[line6man]

Yeah, I'm not seeing the appeal of notch filtering from the bass. That is something you typically do with outboard gear to filter out offending frequencies. And once you have found your frequency center, you typically don't need to adjust anything.

What you can do for tonal effect, if it interests you, is run an inductor in series with the capacitor of a standard tone control, to create a band-stop filter. You will have to play around with the inductance and capacitance to get the frequencies where you want them, however. The only drawback with this is the fact that it can cause volume drops, but it's something to experiment with.

[CosmoReverb]

Ah, Line6man is right. A band-stop filter was much more what I had in mind. The transparency I imagine afforded by the tight Q fall-off seems well suited for a chambered/semihollow fretless instrument at least as far as my limited understanding registers it. It sounds like a sweepable version would be much more complicated, no? Would an active system allow recourse to mitigate the volume drop that you described?

[SGD Lutherie]

If you have a sweepable mid control, and you set it for cut, it's a notch filter. It doesn't matter how wide the notch (Q) is, it's still a notch.

If you set it for boost, it's a band pass filter, although it's not removing the bands above and below.

[J.Wolf]

Still sounds like the most straight ahead solutions would either a pre with the specs the op listed, like the u retro, (2 bands and a sweepable mid control) or a para eq.