Noise Reduction

rickgk

rickgk

Experienced
Posting this new thread to continue a conversation from another thread I inadvertantly hijacked

DonPetersen said:
anyway, why should the Axe compensate shortcomings of the signal fed into it (treating the symptom) while you can easily remove such noise at the source.
Click to expand...

Why should the axe do any of the crazy synth sounds or multitudes of other far out stuff that it does?

Would you wish for a synth block or white noise generator, quad chorus, etc etc if the axe didn't have one?

I simply stated a noise reduction block is something myself and some others would find useful. I am not attacking you or the axe in any way.

My situation is that I believe the noise in my system is due to living less than 1klm from a power grid although there is definitely more noise produced when I am at my p.c. For some reason (led monitor btw)
I don't know how to easily eliminate such noise at the source unless I move house which unfortunately isn't an option. I've tried all the usual things, unplugging all appliances, turning of lights, different power supplies etc etc but with no definitive fix so far.

The puzzling thing for me is that I could crank the gain on my Marshall JVM head OD2 red mode to the max (not that i would normally run it this way but it was a good test as that mode has incredible amounts of gain) with my rocktron hush in the loop and get what I would describe as a perfect 'noise floor', totally silent when not playing (which is no problem with the axe either if I crank the gate) and perfect decay of the note being played until it totally decays naturally, which is what I am unable to achieve with the axe (in my environment)
what seems to happen is the more the note decays the more the 'noise floor' seems to increase then overpower the decaying note.
This is only a subtle thing that alot of players wouldn't even care about, please don't take this as me complaining or attacking the axe in anyway I just think that if I can overcome this issue with the Marshall in this environment then I should be able to do the same with the axe.
Hence my 'wish' for a noise reduction block, not a demand or a complaint, simply a wish.
 
Noise reduction algorithms generally have a lot of latency associated with them and can be processor intensive. Do you have an example of real time noise reduction that doesn't introduce an unacceptable amount of latency or processing power?
 
To my knowledge, the Hush performs two functions; a downward expander (just like the Axe) and a lowpass filter whose cutoff frequency is modulated by the mid-high frequency content of the input.

I agree that the filter section does provide additional noise reduction with fewer artifacts if hiss is the main problem. It may be of benefit if you run noisy stomp boxes with the Axe. But I've found it to be of limited use for general EM-type interference, and practically useless for 60-cycle hum.

Upon first purchasing the Axe, I anticipated that the "gate" would not work as well as my Hush or SNR-2000 (which I connected after my amp, but with the control sidechain taken before the amp). But I found the gate to be every bit as effective due to the lack of self-noise generated by the Axe.

I imagine the filter control algorithm would take considerable CPU. You could build something similar using the available blocks, but you'd have to think and adjust carefully. Or, you could put a Hush in the loop. Even though I don't need a modulated filter, I feel for you. I use to live next to a cell tower, and nothing would help. The interference was overwhelming even when riding a power chord.
 
Right, as steadystate stated you can tie the freq to a pitch or envelope modifier so it not always filtering as heavy.

When I hear noise reduction I am thinking more along these line instead of a low pass filter:
iZotope ANR - Adaptive Noise Reduction

This appears to be a realtime example but I think would be too processor intensive.
 
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