Octave down for Bass???

[audioguy]

My bass player just shot me an Email asking about an octave down pedal for bass Something that adds a fuzzy distortion with the odd synth tones like the MXR Blue Box. But knowing the Blue Box from a previous build, I dont think that would work well... It sucked everytime I tried to play lower than the 3rd position.
Would Joes Shocktave handle a bass signal any better? Or is he plain outta luck?

thanks!

Audioguy

[Mark Hammer]

Success with octave down is only partly a result of good electronic design.  The rest lies in providing the circuit with an instrument that is interested in being helpful.  Certainly the tracking is only as good as permitted by:

• the stability of pitch (not so much finger vibrato on a bass, which is a good thing)
• the predictability and stability of input level
• the matching of all filtering in the pedal to the anticipated range of fundamentals
• the general coherence and complexity of the input signal

Keep in mind that the flip-flop type circuit that provides divide by 2, whether CMOS or discrete, is the sort of circuit that was developed in anticipation of a signal with a known and fixed amplitude and constant waveform.  What we feed them, as musicans, is many steps removed from what they were bred to be able to do, so expecting any of these things to track dependably is misplaced hope in general.

Having said that, clean picking, and rolled off treble, would help a lot, as would some degree of dynamic peak limiting.

[Seljer]

This is a slightly larger build but people have reported some pretty good octave sounds out of it: http://topopiccione.atspace.com/PJ15ShinEiOctave.html

[audioguy]

This is a slightly larger build but people have reported some pretty good octave sounds out of it: http://topopiccione.atspace.com/PJ15ShinEiOctave.html

I dont mind a larger build, but Im looking for something that adds some gristle like the Blue Box does.... Maybe I'll throw together a blue blox for him and see how it goes.

[runmikeyrun]

I hope he's using 18's, i'm afraid anything else will fry.

[Bassmanfox]

I'm a bass player and I was looking for the same thing.  I built the Shin-ei octave box that is linked here and had decent results, but came up with an accidental fix.  Check out http://www.diystompboxes.com/smfforum/index.php?topic=50184.0   All you have to do is change a cap.  All in all though it is a high parts count built, but made from mostly common parts.  It works better than the blue box or the EH octave thing, atleast for bass.    When cranked its SUPER loud and synth like and it will move your speakers nearly out of their shells, but if you dial it back and use the mix switch it adds a pretty well tracked fuzzy octave.  I made the mix switch a foot switch, although its on most of the time.  But like mark hammer says its controlling the input in is key.  The best results and most fun I had with occurs when I use it with a mu-tron III, always AFTER the octave, for some reason it seems to control it or atleast mask any bad tracking.  I find that the pedal tracks even better on guitar.  I like it's "gristle" more than the blue box too.   

[toneman]

Hi Stompers,
i was gonna bid on this Akai UniBass at ebay   #280039594045.
Then, the bidding got over $150!!! yikes!!!
Does anyone know how Akai does it???
It's supposed to be an octave up, but does it do it with full wave diodes??
Or is it some kind of DSP???
Thought this was an *old* pedal, so I was thinking "analog only"  ??
Don't know if it does one octave down also(?)
Does anyone have any tech specs  (schematic) 
Got any jpgs of the insides??   like top & bottom of pcb??   
Sorry for the drooling   
BTW, the EBS Octabass is only octave *down*, not up...

[sfr]

I hope he's using 18's, i'm afraid anything else will fry.

Will trying to run lower frequencys actually damage the speaker?  I was unaware of this. 

I have both a Boss PS-5 and an Electro-Harmonix HOG, and in my experience, running anything below bass guitar range (the two-octaves down voicing on guitar, for example) is incredibly hard to amplify properly with standard guitar or bass amps, although the largest speaker I've used is 15". 

Gotten some okay sounds with direct recording of those voices, so perhaps running direct into a PA or keyboard amp is the solution.   Running bass through either of these pedals, it seems that the sub-octave is really only usuable playing higher up the neck; usefull for multi-voiced sounds when you're mixing in the dry and wet signals, but if you're looking to run the pitch shifted signal only, the range of useablility seems to make it more ideal to just play down in the first position w/o the pedal.  Both of these pedals are probably more voiced for guitar to begin with, but the wall I'm hitting here really seems to be the ability of the amplifier to put out anything that low. 

Isn't the frequency of a Low E on a bass something like 41 Hz?  So an octave down would be around 20Hz?  Is that even musically usefull?

[toneman]

Never mind....I searched.....it's **digital**......rats!!!

[lowstar]

you won´t hit any walls with an octaver for bass.
1) you will hear higher harmonics that will still make the note discernible even if the cab can´t reproduce the fundamental.
2) if it´s a 15" or an 18" or whatever else doesn´t matter - what matters is how low the cab is tuned (frequency response). many modern good 4x10´s are tuned with low rolloff points of around ~30 hz, so with the low b of a 5er being 31hz, that´s pretty good. the surface of the speakers adds, anyway.
3) you won´t damage any bass amp with low signals unless they´re really small combos and you clip the hell out of your poweramp until the voice coil fries. in 20+ years of playing, i was never able to damage a single speaker or amp. if you use bass amps, that is, no geetar amps 

i also built the shin-ei octave from zero´s layout some time ago. the octave sound was very low-pass. i did not like the tracking on bass, for guitar it seemed normal to me, though. i desoldered the pots and put the circuit in the drawer. i built a oc-2 together with my dad on vero one year ago, and that´s the octaver i´m using at the moment. it has a very characteristic sound, the tracking is not too bad. it is a classic, just listen to some pino palladino stuff (paul young). but don´t ask me for the vero layout, it was pretty big, had some mistakes that we fixed on the go and both don´t quite remember (and did not correct on the paper).

cheers,
lowstar

[StephenGiles]

Hrrrrrrrrrrmph........bass should be bass and nothing else

[audioguy]

Lowstar... thanks for the great info. I'm in the process of building the shin-ei so I'll let you know how it goes. I think Im going to do something of a shoot out. put the shin-ei, my DIY mxr blue box and the Shocktave side by side and see what I get.

[choklitlove]

Lowstar... thanks for the great info. I'm in the process of building the shin-ei so I'll let you know how it goes. I think Im going to do something of a shoot out. put the shin-ei, my DIY mxr blue box and the Shocktave side by side and see what I get.

i would try the behringer octave box:
http://www.music123.com/Behringer-Ultra-Octaver-i156768.music

i have one and it tracks far better than the blue-box.  i like the bad tracking though...  anyway, it's a pretty clean octave too, but i'm not sure how it would work with bass.  it would definitely probably dirty-up a little with bass.  on the box it says it's for guitar, bass and keyboards.  it's less than $20.  it's worth a shot for that.  good luck!

[Meanderthal]

 Yep- the behringer octave down for bass is also the ultrabass circuit that's built in their amps. I have one, and the tracking is pretty darn good. Haven't found many uses for it yet, but it works great! OT, but those elcheapo amps sound fantastic (a little dry though) for the loot...

[Dragonfly]

My bass player just shot me an Email asking about an octave down pedal for bass Something that adds a fuzzy distortion with the odd synth tones like the MXR Blue Box. But knowing the Blue Box from a previous build, I dont think that would work well... It sucked everytime I tried to play lower than the 3rd position.
Would Joes Shocktave handle a bass signal any better? Or is he plain outta luck?

thanks!

Audioguy

know what i'd try ?  build a Bosstone without the clipping diodes (it'll still get fuzzy), and increase the input and output caps to somewhere between .1uF and .47uF...its easy to build, you'll get that "octaver" sound...should be real cool...plus its an easy build...

just an idea...

AC

[343 Salty Beans]

I haven't finished either build, but I'm planning to put a ross comp in front of the blue box to help with the input stability.

[Bernardduur]

Maybe not DIY, but the Boss SYB-3 has a very cool octave down;

Just set the mode to an octave down oscillator and set all controls (except for volume) to 0; perfect tracking