blown filters and speaker damage
Hi all,
I have created a patch that generates some very raw and unpredictable sounds and rhythms using a simple bank of eight sawtooth generators (made from phasors), a chain of lowres~ objects, and a chain of simple compressors (based on the simple example). The audio is intentionally overdriven and full of strange artifacts, dc offset and subsonics interfering with audible frequencies.
Here's my problem. I was advised to add a high-pass filter on the output (cutoff at 20Hz) in order to avoid damaging speakers during performances at high volume. However, both svf~ and 2up_svf~ simply blow up (clip, then silence) if I run the output through them, even if I scale the audio level down to 0.0001.
I can record the audio with quickrecord and high-pass it in other software (Logic, for example) without any problem or noticeable change in the sound. Shouldn't there be a way to high-pass it in Max without it blowing up or ruining my glitch party?
I've posted the patch below. I've also made an mp3 example of some of the audio here-
Should I be worried about damaging speakers with this?
This is my first original post to the list, so please go easy on me
Seth
my setup:
Macbook running OS 10.5.8
MaxMSP 5.0.7
try biquad~.
some nice glitchiness there
Well what do you know, biquad~ works just fine.
However, I do notice that the audible sound is significantly changed when I roll off anything over 5Hz. Should I be worried about harming speakers or amps with this audio? I have asked a few people and gotten varied responses. Doesn't most equipment (maybe even the output device of the Macbook) roll off sub-audio frequencies before they make it to the speakers?
Sorry if this is getting too far off topic...
Seth
when sound checking before a performance, start the volume low, load in your noisiest preset and inch up the volume till it's as loud as you want it. voila.
Concerning your patch, using minmax~ I find some presets make the signal reach amplitude values of 160000 or so. Whether or not that blows up the filter, from a programming point of view, this doesn't make so much sense. You might try some clipping within the patch if it is that sound that you like, which is now produced at the dac. It might prevent svf blowing up.
Added to this, I would prevent dc offset on the signal. There are a number of third parties that can filter this. Or you can solder on yourself like this: biquad~ 1. -1 0 -0.9997 0.
dcblock~ is good to prevent speakers blow up but i dont know if it's available in Max 5
[biquad~ 1. -1. 0. -0.9997 0.]
Attenuation starts at approx. 10Hz and kills DC Offset.
Edit: Oops, maybe I should read before posting...
On the other hand, maybe the DC Offset stressing the speaker makes it sound the way you want it.
I've got a blown guitar amp speaker, who's membrane is "loose", so that low frequencies make it jump around wildly. As a result there's some strange/cool compression going on