Michael McGilloway

I'm sure there have been posts on here about this but I've been having trouble finding any. I've been messing around with the idea of running guitar signal through max/msp back into an amplifier for a while now. I have pretty much all I might need for this situation as far as getting the right level/impedence going back into the amp. It's going into my MOTU then back out into a reamp box then to the amp.

But my question is, obviously depending on what the patch does, Max/MSP is capable of producing signals that might damage a guitar cabinet. Is there a more-or-less surefire way to prevent this, assuming I'm using a patch that can get pretty chaotic? My intuition is to just filter out very low and hi frequencies but the question is, what would the optimal range be to preserve a clean guitar signal as much as possible but also ensure nothing too crazy is getting through? Also, is this the only thing I need to be taking into consideration? And is this good enough? Should I look into getting some kind of hardware EQ, like a pedal, so if the software fails it's not going right into the amp?

I'm sure there have been posts on here about this but I've been having trouble finding any. I've been messing around with the idea of running guitar signal through max/msp back into an amplifier for a while now. I have pretty much all I might need for this situation as far as getting the right level/impedence going back into the amp. It's going into my MOTU then back out into a reamp box then to the amp. 

But my question is, obviously depending on what the patch does, Max/MSP is capable of producing signals that might damage a guitar cabinet. Is there a more-or-less surefire way to prevent this, assuming I'm using a patch that can get pretty chaotic? My intuition is to just filter out very low and hi frequencies but the question is, what would the optimal range be to preserve a clean guitar signal as much as possible but also ensure nothing too crazy is getting through? Also, is this the only thing I need to be taking into consideration?  And is this good enough? Should I look into getting some kind of hardware EQ, like a pedal, so if the software fails it's not going right into the amp?


guitar-cabinet-output-from-maxmsp

This is not a problem here because your output device is your audio interface. From there you go to the amp input of your choice.

Put a limiter before your Max output. You can find limiter examples via the Max reference, but it is much easier to use the [vst~] object and load your favorite AU or VST plugin. Be careful with brickwall limiters, they tend to introduce high latency. For live playing better use a softer one and keep your output level under control. Since your audio interface is not a guitar pickup, the sound texture does not change with volume. Better keep your level down and turn the amp louder.

Not necessary unless you need one for performance reasons. If you don't want very low tones, take a [biquad~] highpass at 60 Hz or so at the output and you are set.

Depends on your patch but is generally very good.

Impedance:
This is not a problem here because your output device is your audio interface. From there you go to the amp input of your choice.

Volume:
Put a limiter before your Max output. You can find limiter examples via the Max reference, but it is much easier to use the [vst~] object and load your favorite AU or VST plugin. Be careful with brickwall limiters, they tend to introduce high latency. For live playing better use a softer one and keep your output level under control. Since your audio interface is not a guitar pickup, the sound texture does not change with volume. Better keep your level down and turn the amp louder.

Hardware EQ
Not necessary unless you need one for performance reasons. If you don't want very low tones, take a [biquad~] highpass at 60 Hz or so at the output and you are set.

Quality:
Depends on your patch but is generally very good.


Thanks so much for the response! I'm already in the practice of limiting the output with a vst~. As far as a hardware EQ, I know you can use filtering objects in max, I was just thinking a separate hardware EQ would be safest in case anything bugged out in the software.

To be clear, when I say "running a guitar signal through max/msp", I mean I'm doing things to the signal, it's not just a guitar running straight through then back into the amp. For example all sorts of stuff with envelope following synths and samples.

My thinking with an EQ is just that, say, if I had some sort of patch set up where some kind of really chaotic synth that could potentially generate really low frequencies was feeding into the cabinet it might end up damaging it. My understanding is that frequencies that are too low or high can damage a guitar cabinet. Obviously I wouldn't do this on purpose, just trying to come up with some cabinet safety protocols so I can fool around as much as I like sending signals into the cab to see what sounds good. (When I say into the cab, I mean the amp then the cab.)

Thanks so much for the response! I'm already in the practice of limiting the output with a vst~.  As far as a hardware EQ, I know you can use filtering objects in max, I was just thinking a separate hardware EQ would be safest in case anything bugged out in the software. 

My thinking with an EQ is just that, say, if I had some sort of patch set up where some kind of really chaotic synth that could potentially generate really low frequencies was feeding into the cabinet it might end up damaging it. My understanding is that frequencies that are too low or high can damage a guitar cabinet. Obviously I wouldn't do this on purpose, just trying to come up with some cabinet safety protocols so I can fool around as much as I like sending signals into the cab to see what sounds good. (When I say into the cab, I mean the amp then the cab.)


A cabinet is happy with frequencies from bass (~ 40 Hz) to the usual guitar output (~ 8 kHz) and higher. I would start with a highpass at 60 Hz and the lowpass at 9-10 kHz and probably control that by MIDI. If you take other filters than 2-pole Butterworth or so, make sure that you don't get much resonance in the lows. They wouldn't hurt the speakers but probably your music, lows are more powerful than heights.

If your patch gets too chaotic, a hardware EQ can help. More important may be a volume pedal.

Guitar cabinet output from max/msp