Bass Octave

[Arn C.]

Does anyone have a suggestion of what schematics are available for a bass octave and what I would have to change to use it with a bass?

Thanks!
Arn C.

[Marcos - Munky]

Did you tried the Buzz Box with a germanium diode? Take a look at Runoffgroove. Or maybe the Shin Ei Octave for a clean octave.

[Arn C.]

Thanks Marcos!    Anyone else?
Arn C.

[Mark Hammer]

Can the rest of what follows after such a device in your rig actually handle and reproduce anything that low?  That's gonna be pretty dang low.  We're talking "sensurround" here (the subwoofers used for the commercial release of the movie "Earthquake" way back when).

The other thing I wonder about is what I guess you might call the "car-woofer" effect.  The huge woofers and subwoofers some folks install in their cars may be able to reproduce extremely low frequencies, but unfortunately the wavelength of such ultra-low content means you need to be far enough away from the speakers or else you won't actually be able to hear it.  That distance is actually well beyond the physical perimeter of the car.  Do you or whomever is the eventual user of the device anticipate using it in a physical space that permits it to be physically heard?

These practical concerns notwithstanding, it isn't necessarily a *foolish* idea to aim for a bass octave down (of course if the aim is 2 octaves down I'll change my tune a bit :shock: ).  However it may be foolish to aim for an octave down which is available to ALL notes that a bass can produce.  That means some sort of high-pass filtering prior to the fundamental-detection circuitry to keep out the lowest notes.  (Incidentally, a 5-string bass may well just plain fart-out an "unprotected" octave box).

The other thing you'd want in a bass-oriented octave-box is tonal compatability with the actual instrument sound.  In the case of guitar, something a little more strident is tolerated, but in the case of bass, you'd either want to heavily lowpass fitler the octave tone to smooth it out, or else have a very wide-ranging tone-cut control to give you a choice between a subtly "meatier" sound and something that is more obviously a second note with its own harmonics.  

In some respects, I'd think that the delay imposed by the frequency-division process at frequencies that low would also warrant against having enough harmonic content to make the sub-note onset easily detectable.  Consider that a 100hz note requires 10msec to go through a complete cycle.  Producing a sub-octave would require at least 20msec to detect and produce, which is a noticeable length of time.  If the octave down has a sharp rise time at the pedal output, that delay will, in theory, stick out like a sore thumb.  heavy lowpass filtering will make it seem to "slide in" a bit more, I would think.

These are all conceptually-driven comments.  I've never used an octave down with a bass, and may be way off-base about bass, with no basis. :roll:  Perhaps some folks who may have used the E-H Bass Microsynth (which does provide octave down) may have some comments to offer.

[Arn C.]

Mark,
    Is there such a beast as "octave up"  and would that even make sense?   I asked my bass player friend what pedal he may be interested in and his reply was and octave pedal.   He gave me a set of active pickups and controls for bass, just thought that I would return the favor...
    I also can't see using a bass with octave down, especially when he has a five string bass....but maybe and octave up?  stumped.......
Thanks!
Arn C.

[ethniccheese]

What about the Electro Harmonix Bass Microsynth?  It has an octave down and sounds pretty sweet.  It doesn't sound like it has a lowpass filter since it tries to octave down my low B string.  I say tries because you can't really make out the note, but it still sounds nice.  Being a bass player, octave down is the way to go.  It adds a certain fatness to your sound that you just can't get otherwise.  I have wished for octave down schematics ever since I heard the microsynth.

[moosapotamus]

I've never tried building one. But, I have a few commercial pedals that do octave down for bass... EH bass microsynth, EBS octabass, Akai deep impact (of cource the Akai is totally synthesized). I also have a small Ashdown combo bass amp that has a built-in octave down feature.

In the exterme, I'd guess that Mark's points would be of concern. But, in my experience, octave down on bass just sounds totally wicked PPTTHFAAATT!!! Yes, you do need a sound system that can handle it. But, I think a bigger concern is that accurately tracking a bass signal is apparently pretty tough.

So, I would think that a DIY octave down for bass would be a pretty complex build. The microsynth tracks quite well. Maybe the octave circuitry could be extracted from that. Also wonder if it has any similarities to the EH octave multiplexer.

Octave up for bass? Maybe try a bass brassmaster.

~ Charlie