Signal splitting problem

The i2M musicport™ MIDI Converter & Hi-Z USB Audio Interface

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Ilkka
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Joined: Sun Nov 24, 2013 10:12 am

Signal splitting problem

Post by Ilkka »

Hi Sonuus peolple. I am trying to use both my computer and amplifier at the same time by splitting my guitar signal in two with the Radial BigShot ab-y swithc (one signal to computer via i2M and other to the amp). Everything works fine for about 15 min to half hour. Then there is a slight pop and midi stops working (audio signal to computer still works fine and i2M stays green). To get midi working need to shut down software (Ableton Live) and disconnect i2M USB and connect back again. This doesn't happen if I just plug my guitar to i2M without splitting the signal. Any idea why?

BR
Ilkka Niemeläinen
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james
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Re: Signal splitting problem

Post by james »

Are you using the latest firmware in the i2M? We did identify a (theoretical) problem with MIDI, though we couldn't never prove it was a problem. The latest firmware includes this fix, so just in case this is what you are seeing, make sure you have the latest firmware installed.

When it stops working, you said audio is still ok -- you mean the audio from the i2M is still working correctly?

Which OS are you using?
Ilkka
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Joined: Sun Nov 24, 2013 10:12 am

Re: Signal splitting problem

Post by Ilkka »

Thanks for your fast reply. I updated the firmware, and now i2M works fine.
The audio from i2M worked all the time even before the update. The problem was just MIDI. My OS is Win7 64 bit.

Thanks again, i2M is a nice piece of equipment. Looking forward using it in live perfomances.

All the best

Ilkka
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james
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Re: Signal splitting problem

Post by james »

That's great news. Thanks for letting me know how you got on.
Ilkka
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Joined: Sun Nov 24, 2013 10:12 am

Re: Signal splitting problem

Post by Ilkka »

Hello James,

Unfortunately I rejoiced too early. The same problem appeared again. It first occurred about 40 min after launch. Then it went back to about 15 min frequency.
I tried to reduce the signal chain by disconnecting all the effects. Didn't make any difference. The splitter itself doesn't do any harm. Only when I connect the amplifier.
I also tried a couple of different amps. Same problem.

I have also the G2M, which seems to work OK with its thru option. I am planning to use i2M with reeds in any case. Haven’t tried it yet with a splitted microphone signal though.
With reeds It is of course possible to connect a different microphone just for the midi conversion .

BR
Ilkka
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james
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Re: Signal splitting problem

Post by james »

That's not such good news.

The fact that the i2M audio was working all the time suggests that the i2M is working correctly. So, either the problem is something with the MIDI setup of the i2M (are you using the default presets/MIDI configs, or have you changed these?)

Maybe something in Live is going wrong?

When it does go wrong, do you get the MIDI light on the i2M editor flashing to show it's sending MIDI?
Ilkka
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Joined: Sun Nov 24, 2013 10:12 am

Re: Signal splitting problem

Post by Ilkka »

I dont think Live is the culprit because without spliting the signal live works fine. There is no feedback connction or special routing in the midisetup.
The midi light in i2M editor doesn't work when the signal flow stops. Actually when the problem occures in Live the signal is left hanging, it doesn't get the note off command.
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james
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Re: Signal splitting problem

Post by james »

Thanks for the info. We'll investigate to see if we can find anything that might explain this.
Ilkka
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Joined: Sun Nov 24, 2013 10:12 am

Re: Signal splitting problem

Post by Ilkka »

Hi James,

I have done some further testing. The guitar I used had an active picup. Decided to try another one with passive picup. It worked fluently.
Have you tried i2M with both active and passive picups? Is it just my picup (Shadow electronics SH145) or could it be a more general problem?

Tried also splitting a condenser microphone signal (mixer aux) with good results.

BR
Ilkka
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james
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Re: Signal splitting problem

Post by james »

Hi Ilkka,

That's interesting. We have tried active pickups. My standard test guitars are a les paul (passive) and an explorer-type guitar with EMG actives. But I've never seen this before.

I don't know if this is possible for you to do: record audio that is going through the i2M into a wav file (48kHz, 16-bit mono) and if the MIDI goes wrong, send me that wav file to see if I can reproduce it with the same audio signal you have.

Maybe there is a subtle bug in there with a particular audio characteristic? Maybe it's something else entirely. Anyway, it would be interesting to see if we can reproduce it.

James
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