What makes an effect a Bass effect?

[Scott674]

I guess maybe I should say hello first.  This is my first post here.  I'm new to the scene, I've built a couple of effects from GGG and SmallBear's Tweak-O was my first build.  I'm hooked!    Anyways, I was wondering what the difference between a bass pedal and a regular pedal is?  Or, maybe I could word it this way, if you were going to make a little preamp, like the very simple Guitar Preamp Circuit from the Guitar Handbook, what would you have to change to make it optimal for a bass guitar?

[John Lyons]

Welcome!!

Usually the input cap (first cap) after the input jack is a lot larger for bass. 1uf or more but it does depend on the actual circuit.
This lets more bass into the circuit.
The output cap is larger as well...but this also depends. Lets more bass out of the effect.
For a clean bass preamp you mostly want a lot of bass in and a lot out.
With a distortion type preamp you may find that limiting a little bass going in with clean up the sound and allow more articulation and picking definition.

I recomend a bread board kit and trying a few things with a simple circuit to see how the in/out caps change the sound.
Then after you fiddle around a bit you can build and or adapt different circuits from guitar to bass.

JOhn

[Scott674]

Thank you much John!
P.S. I love your work!  Your wood work looks fantastic!

[s.r.v.]

these will make your life alot easier, at least they did mine!
http://www.smallbearelec.com/Detail.bok?no=101

[Alex C]

Welcome to the forum, Scott.  The Tweak-O was my first build as well, it was a great starter project.  Glad to have you on board- have fun!

-Alex

[Mark Hammer]

What makes something a "bass effect" will depend on what type of effect it is.  In some cases, adapting the effect to a bass means incorporating more of the bass signal in some fashion.  In other instances, adapting it means adjusting to what the bass signal has more of or less of.  In still other cases, it means adapting the circuit such that it interferes less with the bass's natural characteristics.

The most basic aspect is that it can't roll off any of the frequency content that is a typical part of bass output even though it might not be part of a guitar signal (John's comment).

If there is any distortion purposely generated, the treble cut imposed on that distortion may be lower or more severe than for a guitar simply because the harmonics that "matter" to a bass will be lower.

In the case of things like a phaser, chorus or flanger, often the low end of the wet signal is trimmed back such that the effect is really only imposed on the mids and higher.  This is because the pitch of a bass needs to be clearly audible at all times, and anything that causes some perceptible "pitch wobble" tends to result in a poorer blend of bass with other instruments.

If the device has some envelope control, then the sensitivity may be adjusted to suit bass.  In other words, the range of fundamentals the envelope detector responds to is tuned to the bass.  That might be true whether the envelope detector is in service of a noise gate, a limiter, a compressor, an envelope-controlled filter or even a synth.  If it is an envelope-controlled filter, then the range of the filter is shifted downwards such that the frequencies being filtered in or out are optimized for the bass.

When the effect has to somehow "evaluate" a note for some purpose (e.g., an octave divider or something that detects the envelope or a pitch detector for a synth), one of the things that has to be factored in is that bass frequencies have a longer space between peaks and troughs; i.e., a longer wavelength.  So if any averaging across several cycles of the note has to happen, it takes longer to accomplish that, and allowances may need to be made in some aspects of the design because of that.

[Gus]

sometimes marketing, things like using bass effect in the ad or in reviews in magazines and the web.

Often "guitar" effects work fine as bass effects stock.

Making the caps bigger is kind of funny often it makes things worst.

[petemoore]

What makes an effect a Bass effect?
  Using it with bass.
  What makes an 'improved' effect a Bass effect?
  If there's room for improvement, anything from an entirely different circuit or a small modification could be the chosen ticket.
  Say an electra dist gets too 'whatever' [enter 'less than desirable' character here]: simply reducing [for trebly response] or increasing [to make it bassier] input cap value, or raising the supply voltage [to alter distortion characteristics] or adding a voicing option or clipping reduction option [to smooth the clipping or make it more frequency specific] might make it 'improved'.
 

[Mike Burgundy]

...enter the breadboard (as stated).
There's no real rule, just experiment.
With anything that distorts, the rule of thumb (that's no real rule, right?) is increase the signal-chain caps. Don't just increase everything, just the ones in series with the signal. If that sounds crappy, decrease the input caps to the original value or even lower. If that doesn't work, muck about. I kid you not. this will make you come up with cool sounds you'd never find when obeying "rules". Take on the other caps as well - caps from signal to ground will attenuate highs (more if the cap is larger), caps in a feedback loop will do the same, etc. Experiment, listen, figure out what made it sound like that. Big part of the fun (and frustration, sometimes, when you can't figure it out and only realise you've been missing something the next day. Like a bypass switch - haha)
There was a remark about chorus (was that you Mark?) which was right (decreasing bass content in the shifted signal) but not necessarily the way to go - I souped up a dismall B*ss chorus by increasing *all* low end response, plus slowing down the delay - and it worked. It's on the brink of doubling, but if dialled in subtly this is the fattest, swirliest bass chorus I ever heard. I'm still mucking about with a final mix on our last takes, but so far I'm really leaning towards using the miked signal (amp plus effects chain) as opposed to DI and adding chorus on that. That tweaked chorus is my fave to date.

[Mark Hammer]

There was a remark about chorus (was that you Mark?) which was right (decreasing bass content in the shifted signal) but not necessarily the way to go - I souped up a dismall B*ss chorus by increasing *all* low end response, plus slowing down the delay - and it worked. It's on the brink of doubling, but if dialled in subtly this is the fattest, swirliest bass chorus I ever heard. I'm still mucking about with a final mix on our last takes, but so far I'm really leaning towards using the miked signal (amp plus effects chain) as opposed to DI and adding chorus on that. That tweaked chorus is my fave to date.

Hi Mike, nice to see your here again.
Yeah it was me, and while I stand by what I said, let it be known that my suggestion was for one single change to a stock chorus, based on what a stock chorus with typical settings does to bass.  Slowing down the sweep will always result in less perceptible pitch wobble, which also addresses the same concern, and the ultimate goal of both what you suggested and what I suggested: that of having bass notes that feel solidly rooted and solidly-pitched.

Which leads to a more general principle in response to the original question.  "Bass effects" should ideally enable bass to accomplish what it needs to accomplish.  Since bass is normally in the background, a bass fuzz should probably not obscure or mask instruments higher up in the spectrum, so it will have some means to confine its fuzz sound to a pleasing tiger growl rather than a raspy cough.  Since bass often needs to provide a dependable root against which other musicians' notes provide pleasing harmony, maintaining perceived pitch stability (by whatever means) also tends to be a goal of bass effects (which is sort of why you'll rarely see a "bass vibrato" pedal on the market, though I suppose there is always a first time for everything).  Since bass needs to provide a fat sound that delivers a firm foundation, swept bandpass filters tend to mix in some dry signal so that bass never gets too thin-sounding, or else they do something like the E-H Bass Balls with its dual filters, where one filter stays in the low range, never sweeping so high for too long.

Again, all of these things are based around the central principle of "Why do I still need the bass to do for me, even while I'm changing its tone?".