Some ideas about a DIY V-BASS

[CaptainTuna]

(I just wanna start by saying I'm not sure this is the right section for this post, I just couldn't find a better one so I decided to post it here)

Hi everyone!

Last night I just couldn't sleep, so I started thinking about a DIY version of the famous V-bass system by roland. (for those who don't know, check it out Invalid Link Removed)

Ok so basically I just can't understand why it costs that much, I've heard it's around 1500$ which, in my opinion is just too much. So the other night I was like....why not try to make one of my own? I know I won't get anything that will be sounding that nice and probably will get lots of added noise that you don't have with the original, but seriously...I don't really care that much, I just need a hobby for the summer.

So basically I decided to ask you guys help, mainly for the pickups part, not the processing system, as this last part seems pretty doable to me, with a little effort of course. The hard part would be getting information about what string and fret is being played by the bass and then you just associate it with a pre-recorded sound on an sd-card and play it.

I have already used atmega-based (atmegas are microcontrollers, basically small processors that can be programmed with a computer to execcute "stuff") sound boards and the sound plays instantly when you want it too so, as long as the playbacking of sound is concerned, latency shouldn't be a problem.

Now...as I said before...pickups? Any idea on what I could use? I've seen that the v-bass uses so called "divided pickups" which, as far as the name suggests, should give you a divided signal for each string, right? Theirs cost like 250$. Still too much for me If they're just divided and that's it ( = no other electronic circuit inside or conversion of any kind ) couldn't it be done with any regular pickup? Instead of having a single cable come out of them you'd just need to separate the coils and have a wire coming out of each one and a common ground wire.

Alternatives would be...cheap MIDI or cheap divided pickups?
Any info about those?

...well i guess that's it for today. Sorry if the post looks like a mess, hope you'll excuse me. If you have any other idea please tell me!

 

[Oobly]

Normal pickups have one coil for all 4 strings except split coil P-bass pickups which have one coil for each pair of strings, so you can't "separate the coils".

You'd have to build your own pickup with individual coils sensitive enough to pick up the signal from each string and mount it right near the bridge to help eliminate harmonic content.

Then you need to design a circuit to detect the frequency of the string vibration and convert it to some usable signal.... Not trivial.

Better to just buy one of these and use midi: http://www.amazon.com/Sonuus-Products-B2M-Universal-Converter/dp/B0033Q47CU

 

[CaptainTuna]

big problem with those modules is that they don't "support" chords, they work with single notes only, and that's why they don't need divided pickups.

Converting frequency to voltage is not that hard, not saying it's easy...but it can be done. That part doesn't scare me much. What I'm trying to understand right now is whether I really need to buy divided pickups from Roland or if I can make them myself or ask someone (have some luthiers around here which also make pickups) to make it at cheaper prices than 200+$.

 

[mikezimmerman]

I'm a little confused as to exactly what it is you're trying to build. You mentioned a DIY V-bass, but then ask about divided pickups.

The divided pickup is not part of the V-bass--it just provides a 13-pin output from the bass with separate channels for each string that gives a signal to the V-bass. The V-bass can be used with other types of magnetic and piezo pickups as well, as long as they give the Roland-type 13-pin output with separate channels for each string, in the format Roland is expecting (which also includes channels for paging up and down through settings, I think).

What the V-bass itself does is manipulate the output from the pickup to model different types of tones, from different types of strings to all sorts of synth-type sounds. The original V-bass didn't do any MIDI or pitch recognition, which is why it didn't suffer from the tracking issues that MIDI converters did--there's no requirement for it to figure out "what string and fret is being played"--but it also didn't trigger samples or anything like that. All the sounds were created by manipulating the original signal from the pickup. The new VB-99 also does MIDI conversion, I think, but that's really a different thing than the modeling that's its forte.

Mike

 

[CaptainTuna]

Yep I asked about divided pickups because I believe it's the first step I have to go through if I want to achieve a "sampling machine".

About the v-bass...oh...I guess I was not well informed. I thought it was basically a machine playing samples. I don't get how it can alter the sound so much to make it sound like other instruments though, like organs, trumpets, etc.... that's probably what made me think it was actually sampling sounds and not just altering them.

So basically what I want to build is not a diy v-bass then, it's more like a sampler which gets information from a divided pickup.

 

[mikezimmerman]

I thought it was basically a machine playing samples. I don't get how it can alter the sound so much to make it sound like other instruments though, like organs, trumpets, etc.... that's probably what made me think it was actually sampling sounds and not just altering them.

Since you linked to the original V-bass and not the new VB-99, I can tell you from experience that it doesn't have any sounds that sound like either organs or trumpets. It mostly models varieties of basses, guitars, and strings, plus synth types that that can be done with waveform manipulation. It also has amp and effect modeling, which you can use without the divided pickup.

The new Effects also does MIDI conversion, so you can use it to trigger MIDI samplers. Bass-to-MIDI conversion has issues, though--you'll see a lot more discussion of those if you do a search for "MIDI" in the Effects forum.

Mike

 

[Oobly]

Well, I guess the OP means something more like the GR-55 synthesizer. It uses the signals to trigger samples as well as having the COSM modeling stuff.

You can wind your own pickups, especially since you are building your own frequency detection circuits for them. If you do it well, it should be able to detect and trigger samples from all four strings at the same time, too.

I suggest some 42 guage enameled wire and some small neodymium rod magnets. I guesstimate about 7500 windings per coil should give you a reasonable signal to work with, but quite a lot of work to wind.... will be about 150m of wire @6.05 ohm per metre it comes to about 900 ohm per coil. The signal will be weak compared to a normal bass pickup, but should be enough to work with.

Please post more if you continue with this project... It's an interesting one.