Sub octave for bass

[connie_c]

Dont know if any of you have heard the sub octave sound on the roland bass cube amps. im addicted to it. anyone have any schematics or suggestions for a sub octave bass effect build. Just something that makes me sound like im in jamiroquai.

[oskar]

I don't know about the amp you're refering to but search the forum for the slacktave.


oskar

[Radamus]

Is it a suboctave for a bass guitar or a suboctave that creates bass? I built a blue box a while back and found the suboctave to be way too low. Maybe my amp's not good enough.

[oskar]

The bluebox is two octaves down and that is probably a bit low for base (or your amp). You can just take the output from the first divider in the 4013 and it will be one down instead.

[Radamus]

Well, that could explain it. I never got that pedal to work properly anyway. So the answer is bass guitar?

[oskar]

Sorry. I missed your question.
The answer is:It's a suboctave that creates bass...
The bluebox amplifies and squares the signal so you get a square enough signal to drive a digital chip. The 4013.
In this circuit the 4013 is configured as a divider/ counter and it litterally counts everytime the signal goes from digital "0 to 1".

[connie_c]

Its for bass guitar that im interested in. The amp is a cheap practise amp thing. I work in a music shop and i have just been playing through it a good bit lately.

Id like a similar effect for my own interest, for home recording and just for the challange. Since posting ive discovered a few videos of people playing bass through the EH Octave Multiplexer. That seems to be a very close sound.

Im a guitar player usually but i like to dabble with bass.

[oskar]

Is this the amp you've been trying out?
http://www.roland.com/products/en/CUBE-30_BASS/index.html

It's doing some DSP thing... There's a lot of ways to go about to make octave effects. The ones people try out here are usually:
amplify/lowpass filter --> comparator/schmitt trigger --> Mixer
This will give you a synthy square wave which is how the bluebox (two octaves below)or slacktave(one or two octaves below) works.

You can also create a squarewave as of above and let that squarevawe, which now is in essence digital turn on and off an analog switch like a 4016 or an OTA assigned for the job. The analog switch cuts in and out the original signal but at half the frequency of it's fundamental. This is how the EHX microsynth works.

I don't know what the Bass 30 cube is doing but as it's digital it can achieve the job by digitally modelling the methods above or by just recording the sound and instantly feeding it back at half the frequency. Try and compare the sound to another digital FX unit like a zoom pedal... I don't think it will sound that different.

Check out the slacktave and also some kind of envelope filter is what you need to apply for jamiroquai...
Anyway you go about to create a suboctave there is going to be just hours of funky happiness going on...     

[newfish]

For what it's worth,  a good friend of mine swears by a BOSS OC-2 for his bass.

He plays a 5-string (low B) without any complaints.

[liquids]

Not to rain on the analog parade..but have you demoed anything with digital pitch shift?  This is probably what is in there and more of what you want.  My friends Behringer amp has that going on, and it's interesting, different than analog octaves.  MU lexicon has a cheesy whammy-like pitch shifter and that does it to.  A (digital) EH Micro POG may do it, Boss OC-3 which is digital I believe, as may any other digital pitch shifters....at this stage in the game, most lo-fi digital pitch shifters do a fairly good job, affordably and convincingly enough that it's an add on bonus option for cheapo amps.   

But odds are you want to build something!  Analog it is...  As noted by others lots of 'analogish' octaves create an octave down, but have other stuff that comes along with it...some effects keep the other stuff as part of the sound as it adds character (blue box, shocktave, slacktave, etc) and others try and filter it out (OC-2, Foxrox Octron, etc).    The sound your getting off a digital effect is going to be more 'pure' and sound more like a filtered octave.   

The pearl octaver I stumbled across the other day on this site sounded like a good move in that direction...try this http://gaussmarkov.net/wordpress/circuits/octaver-clone/

But honestly, it depends on how convincing an octave your ears want to hear...You could build a bunch of this stuff and be left unsatisfied, depending on how picky your ears and your needs are, and in the end save money just by buying something instead.  I'd demo and or breadboard some stuff that is out listed above to narrow down what you do/don't want before you build anything that seems like it will for sure be the ticket.

As a side note, I heard a bunch of the old sublime tunes lately on the radio and never noticed that the bass one a lot of those tunes is a a straight ahead synthy square-wave thing in a 'pure' sub octave, with no 'normal' octave sound at all...possibly with some filtering, for a 'dub' sound. Very smooth, pitch-only (no attack) type of thing.  Is that a synth?  It sounds pretty filtered and clearly square-wave to be a synth....Anyone able to cop that sound or know what was going on there?

[connie_c]

Thanks for replys all, really what i want to do is create myself an all in one bass effect one day with fuzz/overdrive, suboctave and a compressor with 3 footswitches and with options to reorder the effects. Wanna try building an analogue sub octave as a first step in the longterm goal of building the 3 in one.

Ive built a few distorions now. compressor seems a managable build although im yet to build one. the suboctave is where the hard work will be.

The roland one is definitly digital but it sounds amazingly good. The amp is fine for the money but the effect is just spot on.

Ive listened to the pearl octaver sound clips and it seems like a good place to start. Thanks again for the ideas.

[ayayay!]

Just something that makes me sound like im in jamiroquai. 

First, you'll need a goofy hat.   

[rousejeremy]

Does anyone have soundclips of the slacktave with a bass guitar?

[snap]

M51134P

[Projectile]

As a side note, I heard a bunch of the old sublime tunes lately on the radio and never noticed that the bass one a lot of those tunes is a a straight ahead synthy square-wave thing in a 'pure' sub octave, with no 'normal' octave sound at all...possibly with some filtering, for a 'dub' sound. Very smooth, pitch-only (no attack) type of thing.  Is that a synth?  It sounds pretty filtered and clearly square-wave to be a synth....Anyone able to cop that sound or know what was going on there?

I always thought it was just a Fender P-bass with the tone control rolled all the way down played through a ported cab with 15" drivers. That's how the classic dub bass sound is usually achieved.  The fundamental of a low E string on an electric bass guitar is 41Hz, so that's plenty low enough. You just have to filter out all the mid to high frequency content and then boost the fundamental.

A sub octave on a low E string is around 20Hz, so it would be practically inaudible. Most speaker cabs don't even go down that low without trouble. What most of these bass sub octave generators actually do is generate harmonics related to a sub octave frequency to "trick" the brain into thinking there is  something going on down there, and the brain does the real work of filling in the bass, not the speaker. I imagine this trick is a lot easier to do in DSP than with analog circuits. Roland may have stumbled upon a particularly nice implementation for their amps, but it's probably more of a "low harmonic generator" than an actual octave generator.

[stobiepole]

I think you want a filter like a Meatball (the McMeat project), or something like the original DOD FX25 to emphasise the lower frequencies and cut the highs:

http://topopiccione.atspace.com/PJ11DODfx25.html

Just set it below the envelope triggering point and you'll sound just like Bill Laswell (it's the pedal he uses for his deep dub sound)...

Chris

[Mark Hammer]

The elephant in the room here is string scale.  Most guitar players who use analog octave dividers will tell you that the thing doesn't really respond very well below the 5th fret, and sometimes not even below the 7th fret.  Why?  Because the string length vs pitch of the normal contemporary guitar is such that the string doesn't really start to get "stiff" until you get higher up.  YES, I know that strings are easier to bend as you get closer to the middle (10th to 12th fret), but once you fret, the string length is short enough that the string isn't "floppy".  Perhaps more to the point, there is not enough give in the string that plucking necessarily bends the pitch.  So, when picking higher up, it becomes far easier for a stable fundamental to be detected.

And therein lies the issue.  Conventional electric basses have a much shorter scale than they really ought to (i.e., what you would see on an acoustic stand-up bass).  To achieve the lower pitch, one of the strategies adopted is to loosen the strings so that they end up being floppier.  And even though basses have a longer scale than a guitar, or even a baritone guitar, they are still short enough to result in unstable pitch at the outset of a plucked note, which will make the behaviour of the division process unpredictable and unreliable.  If that's what you want, fine, but it seems to me that much better tracking performance would be had from a digital device that didn't need to detect the pitch, but simply bumped everything up or down digitally by a given coefficient.

The alternative is to use the stiffest strings possible.  For a guitar, that would likely mean a nice set of flatwound .012-.056 (or heavier) on a long-scale guitar.  We're talking about strings that feel as tight as those on a piano.  I don't know what the equivalent is for bass, but I'm guessing that flatwounds would also be the order of the day, since they tend to be less flexible and give absolute priority to the note fundamental.

[oldrocker]

The one octave down mod for the Blue Box is shown below.  Using a SPDT switch is needed.  Although I still don't think it works very well for bass without more modifications.  I thought the Joe Davisson Shocktave worked better on the bass but it's not a clean octave down.