B2M on Pedalboard for Live Use

The B2M™ Universal Bass to MIDI Converter.

B2M on Pedalboard for Live Use

Postby yocummr » Fri Feb 20, 2015 10:23 pm

Hi folks,

I am enjoying my B2M, which I use with an Alesis Nanobass and a Moog Minitaur. What I am noticing most and trying to adjust my playing for is not wrong notes, but rather multiple triggers of the same note with a single pick stroke. The B2M seems to react a little differently to my different basses. My active Sadowsky P/J seems to work best on the treble (Jazz) pickup with its volume down and the vintage (i.e., passive) tone control rolled off. My passive Squier 50s Precision with a Joe Barden humbucker works best with the tone rolled all the way off and the volume part way down. My passive Fender Bass VI works best on one single coil pickup, the volume down a tad and the tone rolled off. I play each almost exclusively with a Herco Flex 75 nylon pick.

When I play normally on any of my basses, I play with the volume control and any passive tone full up. Right now on my pedalboard, I use the non-switched output of my Boss TU-3 Tuner to feed the B2M, while the switched (i.e., mutable) output goes to the rest of my bass pedalboard. I then have a Boss AB-2 pedal at the end of the pedalboard that sends either the effected bass signal or the output of a synthesizer (fed by the B2M) to my amp. The reason I am set up this way and not simply taking the signal output of the B2M to the rest of my pedalboard is that the B2M has that timer which shuts it off if no signal is going to it for 30 minutes. The thinking here is that if signal is always going to the B2M (i.e., since I don't mute the signal to it with the tuner), then it is less likely to shut off. It hasn't been a major problem, just a concern.

So this has me thinking about the mismatches between my normal bass signal and what the B2M really wants to see, which leads to a couple of questions for you:

  • I think I read somewhere that the B2M evaluates its input signal and makes internal adjustments over time to its algorithm based upon that. Is that true? If so, am I right in thinking that it's probably NOT a good idea to feed the B2M a signal it doesn't like when I’m playing unMIDIed bass (i.e., the red clip light often coming on)?
  • What if I put some sort of bass EQ with a level control right before the B2M? I could filter out highs and change the level of the signal before it reached the B2M, even when I wasn't using it, to better condition the signal for it. Does that make sense? We know the B2M doesn't like highs, but does it have a sweet spot? The doc says that MIDI note number E5 is the top of the B2M range, with translates to 659.26 Hz, so cutting above that and maybe even lower seems right. Is there any place below that, say 400 Hz, where a tiny bump in the response might make sense? Or would you recommend a simple smooth low pass curve on the EQ?
  • If an equalizer is overkill, perhaps just a level control and a low pass filter prior to the B2M would be better?

Sorry for the long-winded explanation and all the questions. I appreciate your help!

Thanks,
Mike Yocum
Washington IL USA
yocummr
 
Posts: 2
Joined: Fri Feb 20, 2015 9:02 pm

Re: B2M on Pedalboard for Live Use

Postby james » Sat Feb 21, 2015 11:56 am

Hi Mike,

You are on the right track. See my answers below.

yocummr wrote:Hi folks,
  • I think I read somewhere that the B2M evaluates its input signal and makes internal adjustments over time to its algorithm based upon that. Is that true? If so, am I right in thinking that it's probably NOT a good idea to feed the B2M a signal it doesn't like when I’m playing unMIDIed bass (i.e., the red clip light often coming on)?


This is correct. The algorithm adapts to the level for tracking MIDI velocity, and also the level at which the input is considered too low to measure (i.e. it assumes noise). If you put in a large clipping signal, then use a "normal" signal that's much lower level, the lowest-level notes might get lost. So its best to keep feeding the B2M your "normal" level signal.

yocummr wrote:Hi folks,
  • What if I put some sort of bass EQ with a level control right before the B2M? I could filter out highs and change the level of the signal before it reached the B2M, even when I wasn't using it, to better condition the signal for it. Does that make sense? We know the B2M doesn't like highs, but does it have a sweet spot? The doc says that MIDI note number E5 is the top of the B2M range, with translates to 659.26 Hz, so cutting above that and maybe even lower seems right. Is there any place below that, say 400 Hz, where a tiny bump in the response might make sense? Or would you recommend a simple smooth low pass curve on the EQ?


  • It's not so much high frequencies that the B2M does like, but a weak fundamental tone. The B2M has internal filtering that will remove high frequencies. The problem is sometimes the fundamental is so weak compared to the harmonic that the B2M can't see it so can't always detect the correct note. Mostly it does a good job even with a weak fundamental, but the stronger you make the fundamental the better. That's why plucking near the neck is better than plucking near the bridge: you excite a stronger fundamental tone this way.

    EQ can't fix this because the EQ would need to be different for every note: you would want to boost the fundamental tone and not the harmonics, and that changes with every note.

    But EQ can help remove higher frequency finger noise, slaps etc, which will help.

    yocummr wrote:Hi folks,
  • If an equalizer is overkill, perhaps just a level control and a low pass filter prior to the B2M would be better?

  • A simple level control may be all that's required. Perhaps with some roll-off on the highs (400-600Hz, depending on how it affects the highest notes you are playing). This could probably be done with a couple of resistors and a capacitor.
    User avatar
    james
    Site Admin
     
    Posts: 1844
    Joined: Fri Jun 06, 2008 8:12 pm

    Re: B2M on Pedalboard for Live Use

    Postby yocummr » Mon Mar 09, 2015 7:20 pm

    James,

    I appreciate your thoughtful reply. I have added an equalizer before the B2M, which allows me to filter and to set the level going into the B2M. It has helped a lot!

    I have another issue to share. I wasn't sure what the problem was before, however now I think I know what it is. Sometimes when I play, I get what I call a double trigger. After I play a note and then stop playing it, a note will sometimes play immediately afterwards. I wasn't sure exactly what was happening, so I fed the output of the B2M into a MIDI tracker. Here is what I got when I played a low G on the third fret of the E string on two occasions:

    21:03:46.657 [Note On] ch=0 note=31 velocity=116
    21:03:48.474 [Note Off] ch=0 note=31 velocity=0
    21:03:48.475 [Note On] ch=0 note=30 velocity=23
    21:03:48.570 [Note Off] ch=0 note=30 velocity=0

    21:06:19.155 [Note On] ch=0 note=31 velocity=120
    21:06:21.475 [Note Off] ch=0 note=31 velocity=0
    21:06:21.476 [Note On] ch=0 note=29 velocity=4
    21:06:21.611 [Note Off] ch=0 note=29 velocity=0

    I am being careful to be in tune, to play precisely and avoid extraneous noises. The chromatic switch doesn't seem to make a difference for the double triggering, although I had it on when I was recording to clean up the output. Any ideas to avoid this that I can try?

    Thanks,
    Mike
    yocummr
     
    Posts: 2
    Joined: Fri Feb 20, 2015 9:02 pm

    Re: B2M on Pedalboard for Live Use

    Postby james » Mon Mar 09, 2015 9:24 pm

    The low velocities suggest that it is measuring a new note at a lower level. Could you be moving your fingers from the strings that cause a small noise to retrigger a note? I've seen this before with very resonant instruments, but usually the glitch note is a harmonic because you lift your fingers at a position that corresponds to a harmonic and the string can ring.

    Are you able to record some audio at the same time as this happens and send it to us? If you can send it as a wav file I will look at it and see if I can work out exactly what's happening. Ideally, sent the wav and the results from the MIDI monitor.
    User avatar
    james
    Site Admin
     
    Posts: 1844
    Joined: Fri Jun 06, 2008 8:12 pm


    Return to B2M™ Support

    Who is online

    Users browsing this forum: No registered users and 2 guests