30 db boost for a bass guitar. LPF 15.5 kHz...

[AndersonENGINEERING]

what are your thoughts on 15.5 kHz for a LPF for a bass guitar on a bass amp? i don't have a great bass amp, and don't feel comfortable giving my opinion on the tone with my bass rig (read as I play guitar 99.99%). i made at and it sounds good, i am just looking for all of your thoughts on this.

the circuit is a heavily tweaked ZVEX SHO with the low pass filter at around 15.5 kHz. obviously this is far to low for a guitar, and i was building it for a bass. but i am just looking for opinions from people who use boosts with their bass.

in the next six months though i WILL have a proper bass rig. ampeg SVT PRO and 4x10" then i will be able to pass judgement. lol. not through my current POS bass rig.

[ElectricDruid]

..with the low pass filter at around 15.5 kHz. obviously this is far to low for a guitar..

Something weird is going on here. 15.5KHz isn't low, and it's certainly not far too low for a guitar. That'd be full audio bandwidth for a guitar, no problem.

Do you mean *highpass* and 15.5 *Hz*? That could reasonably be described as far too low for guitar.

[R.G.]

What Tom said. Did you really mean 15kHz, or is there a decimal point misplaced?

For background, although we say humans hear 20Hz - 20kHz, only young people who have not been exposed to loud sounds (ear buds, headphones, or loud music venues, etc.) can hear much above 12kHz. Single coil pickups don't have much output above 7kHz, if that. Normal bass pickups are wound so they have more output, but lose even more highs than normal single coil pickups, so 2kHz-3kHz is good high frequency response for simple bass pickups. 12" guitar speakers by themselves start falling off in response at 2kHz to 3kHz as well. And bass-specialized speakers usually trade off high frequency response for lower and more bass response.
So having a 15.5kHz low pass filter won't do much at all to a typical guitar rig.

[Digital Larry]

30 dB boost though!  Whoa!  What's that all about?

[Fancy Lime]

30 dB boost though!  Whoa!  What's that all about?

Getting super high gain distortion from the SVT, maybe? Gonna need two SHOs for 30db, though.

Andy

[antonis]

what are your thoughts on 15.5 kHz for a LPF for a bass guitar on a bass amp?

Definately a very quiet bass amp..!! 
(unless, of course, you own a bass guitar with about 160 frets or so..)

[PRR]

The higher "harmonics" of a string are inharmonic. This is one reason why playing guitar through a hi-fi system sounds bad. E-guitar almost has to be high-cut at 5kHz, often lower, to avoid harshness (not "good harsh"). Aside from the mentioned top-cut in pickup and cable, "for guitar" speakers invariably(?) have a steep fall-off by 5kHz.

I could imagine most band-bass needing a top-cut at 3kHz, even 1.5kHz.

I have heard fingered jazz piccolo-bass with deliberate string-squeak above 2kHz, maybe higher, but only once in a long career.

[Rob Strand]

Look at the old Eden amps.  They use a low-pass filter.  Personally I quite like the sound of it when you use a cab with a tweeter.

Apparently Eden changed the low-pass filter at some point and people suspected something had changed in the sound.   There was a thread on the web where one guy analysed a few models and found the model/filter he liked most.

The Sadowsky on board preamp had a bit of low-pass filtering going on too.

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Here's a filter from an Eden amp.  It is a combination high and low-pass,

https://web.archive.org/web/20161226062020/http://cafewalter.com/2000/02/20/partial-schematic-of-eden-wt400-bass-amp/

I've got my doubts about the correctness, maybe the 33pF is actually 330pF? [yes, 330pF]

You cannot separate the components of the  low-pass and high-pass filters as the two interact.  However you can look at the over all response and match your own low-pass filter - that's only necessary if you want to copy that specific filter.

I can't find the old thread with the analysis an mods, by a different guy

It's not this one but at least here it confirms the cap is 330pF and not 33pF,

https://www.diyaudio.com/forums/instruments-and-amps/137725-modifying-preamp-frequency-response-eden-wt-800-wt-400-a.html

[AndersonENGINEERING]

30 dB boost though!  Whoa!  What's that all about?

Getting super high gain distortion from the SVT, maybe? Gonna need two SHOs for 30db, though.

Andy

exactly this. i want to hammer the heck out of it. i am going to recalculate my filter and for bass put it at 2kHz LPF. that should take the pop, snap, and string noise off.

thank you guys for the insight. i am still new at this.

cheers brothers!

[Fancy Lime]

30 dB boost though!  Whoa!  What's that all about?

Getting super high gain distortion from the SVT, maybe? Gonna need two SHOs for 30db, though.

Andy

exactly this. i want to hammer the heck out of it. i am going to recalculate my filter and for bass put it at 2kHz LPF. that should take the pop, snap, and string noise off.

thank you guys for the insight. i am still new at this.

cheers brothers!

Hmm. Are you sure that this is what you want though? In my experience, pushing bass amps into high gain overdrive can work as a special effect for intros or apocalyptic noise-scapes but is rarely usable as a "Sound". And in the setup you describe, you cannot easily switch between the sounds. Can you tell us what sound you are after? We may be able to recommend some more flexible alternatives.

Andy

[strungout]

As a guitarist and bassist, I'd say get yourself a parametric EQ. Up to a certain point, you'll be able to EQ your way to a sound you like. You can boost or cut certain frequencies. That would be my bet. 4 bands in the bass to low-mids region would do good, I think. You'd be able to dial-in the frequency that makes your amp boogie (its resonant frequency). That does a lot for boomy-ness. If that makes any sense.

My rig is a Warwick BC20, basically. Made for 5-string and it responds really well. But like I said with a parametric EQ set for bass, you can dial in you amp's resonnant frequency and make it boom all day!