eliminating noise!?

[hippietim]

Depends on your definition of "noise". The correction definition of noise is a random signal caused by thermal agitation of the atoms in a conductor. Any atom higher than zero degrees Kelvin will experience electrons randomly switching in and out of valence states (IIRC). This causes random electron flow in the conductor. The higher the resistance of the conductor the more this random electron flow will induce voltage since V = I*R. This is known as Johnson noise. Johnson noise is proportional to resistance and temperature ( = sqrt(4*K*T*B*R) where K is Boltzman's constant, T is temperature in Kelvins, B is bandwidth in Hz and R is resistance).

Since Johnson noise is random and the signal from your guitar is also random then there is no way to separate the good from the bad.

Now "interference" is a different thing. Interference is not random. In our microcosm interference is typically electromagnetic interference from nearby radiators. In the old days it was predominately 60 cycle in nature but with the advent of computers and binary power supplies this interference now includes high frequency sources. However you can't predict what that interference will look like so removing it is nearly impossible. You can put notch filters in to remove 60 Hz interference but that still damages the desired signal.

The best way to remove interference is to shield against it. There are two possibilities: shield the source or shield the receiver (or both). Since you may have no control over shielding the source that leaves shielding the receiver, e.g. shielding your guitar and using well-shielded cables.

 

[quonsar]

Johnson noise is proportional to resistance and temperature

Johnson noise is reduced substantially if you've been in the pool.

 

[Soultrash]

Depends on your definition of "noise". The correction definition of noise is a random signal caused by thermal agitation of the atoms in a conductor. Any atom higher than zero degrees Kelvin will experience electrons randomly switching in and out of valence states (IIRC). This causes random electron flow in the conductor. The higher the resistance of the conductor the more this random electron flow will induce voltage since V = I*R. This is known as Johnson noise. Johnson noise is proportional to resistance and temperature ( = sqrt(4*K*T*B*R) where K is Boltzman's constant, T is temperature in Kelvins, B is bandwidth in Hz and R is resistance).

Since Johnson noise is random and the signal from your guitar is also random then there is no way to separate the good from the bad.

Now "interference" is a different thing. Interference is not random. In our microcosm interference is typically electromagnetic interference from nearby radiators. In the old days it was predominately 60 cycle in nature but with the advent of computers and binary power supplies this interference now includes high frequency sources. However you can't predict what that interference will look like so removing it is nearly impossible. You can put notch filters in to remove 60 Hz interference but that still damages the desired signal.

The best way to remove interference is to shield against it. There are two possibilities: shield the source or shield the receiver (or both). Since you may have no control over shielding the source that leaves shielding the receiver, e.g. shielding your guitar and using well-shielded cables.

thanks for the very detailed explaination, i really thought that this was not that complex but damn was i wrong

 

[Soultrash]

You need to check for ground loops. Here's the deal, if there is wires connected to the bottom of your pots, and your guitar is shielded, you have created a ground loop. More than one. Modify your wiring to account for the pots being grounded to the shielding, then take 1 wire off the shielding to merge with the audio grounds, then out of the cable. This fix will make your guitar even quieter, as it will be fully shielded from interference, and ground loops. I can show you my wiring if it would help.


Noise gates work well when they track the guitar signal. My ISP Decimator 2 G-String does NOT cut off sustain, at all. It just ensures when the signal is off, the noise is clamped. This does not reduce noise while playing but it certainly ensures everything is quiet when your guitar is muted, and no sustain is affected by the gate.

i am a total noob when it comes to things like that, though my guitar was expensive enough to have a proper shielding, haha,
ok but seriously, i discovered that the cavity is painted with black shielding paint, however the cavity cap is not painted.
would it help to paint the cap? everything else looks quite solid, cables are soldered nicely and there is no lose cables etc.

i might have a problem with the input jack though, it gut's off the signal when i move the cable around, is there an easy fix for this?

 

[Soultrash]

It very well could be radio interference from your guitar! I was just recording bass takes for a song with my buddy, his bass was totally just picking up the radio. LOL I'm gonna have to fix his issue. I had to pump the gain to identify it , but it was the radio. I would wager this is your issue, not 100% sure, but ... this is not the first time for buddy and his bass. We had a recording ruined because of it one time. Not a final thankfully, but ya, annoying.

haha, had this happen quite a few times with my older guitars, also my headphones seem to be quite attracting for radio waves

 

[pauly]

G'day,

I have a number of noise reduction plugins that have a 'Learn' feature... You playback a 'blank' part of a track (with just the noise) and tell the plugin to learn that noise signature. Then, you take the plugin out of 'Learn' mode, and it removes the learned noise signature from the track. I guess if I was thinking about doing that on the Axe FX, I'd implement a similar technique where the user creates a preset that sounds great, then adds a 'Denoiser' block, then 'Learns' the noise the guitar & preset produce. - Then the user could dial in how much of the noise to remove, & the denoiser block would eliminate the learned noise.

Maybe.... but WTF would I know? ;-)

Thanks
Pauly

i was just thinking if it would be possible to give us an option/switch that removes/dampens amp noise!?

i am not talking about a noise gate but more something like cliff "coding" the noise out.

as the axe-fx is a digital unit so many things can be programmed, distortion, saturation etc. logically it should be possible to remove amp noise with out altering the amp sound in general, right?

if so, i'd be really glad for such an option, it would make
recording much easier. i mean noise gates work but they surely have their limits...

what do you guys think?

 

[brads4]

G'day,

I have a number of noise reduction plugins that have a 'Learn' feature... You playback a 'blank' part of a track (with just the noise) and tell the plugin to learn that noise signature. Then, you take the plugin out of 'Learn' mode, and it removes the learned noise signature from the track. I guess if I was thinking about doing that on the Axe FX, I'd implement a similar technique where the user creates a preset that sounds great, then adds a 'Denoiser' block, then 'Learns' the noise the guitar & preset produce. - Then the user could dial in how much of the noise to remove, & the denoiser block would eliminate the learned noise.

Maybe.... but WTF would I know? ;-)

Thanks
Pauly

Every one of those noise reducers is a destructive algorithm. It's far better to fix the root problem, than to duct tape it all the time.

 

[firmani99]

Its kind of funny that the axe has come so far modeling real amps that we are now trying to remove characteristics of real amps! Haha

 

[pauly]

Gday Brad,
Granted in a black and white world -however- if you have (say) a telecaster & high gain amp, in a studio with light dimmers etc, you'll get some noise. As a matter of fact you might get some noise anyway - that's what this post is about - getting rid of noise that exists. I make the assumption that whatever noise is on our recordings is noise that's left after we've done all we can.
The smart thing about the plugins I mentioned is that they take a 'print' of the unwanted noise and remove that from the signal. That doesn't mean there aren't artefacts but the user can decide to what extent the reduction is applied. All good stuff as far as I'm concerned.

Pauly

Every one of those noise reducers is a destructive algorithm. It's far better to fix the root problem, than to duct tape it all the time.

 

[apescaleconflict]

I had MAJOR issues with noise with my Jackson and the reason was my CPU that did huge noise interference to my pickups. Eventually had to move my CPU by two meters This Issue is bigger with passive pickups than active. Monitors might do a lot of damage too.

 

[brads4]

Gday Brad,
Granted in a black and white world -however- if you have (say) a telecaster & high gain amp, in a studio with light dimmers etc, you'll get some noise. As a matter of fact you might get some noise anyway - that's what this post is about - getting rid of noise that exists. I make the assumption that whatever noise is on our recordings is noise that's left after we've done all we can.
The smart thing about the plugins I mentioned is that they take a 'print' of the unwanted noise and remove that from the signal. That doesn't mean there aren't artefacts but the user can decide to what extent the reduction is applied. All good stuff as far as I'm concerned.

Pauly

Am I wrong to assume that completely properly shielded guitars will in fact not get any noise??? I know I certainly am picking up no noise at all in my recent recordings with my first perfectly shielded guitar. And I'm talking about checking at super high gain. Perhaps I am missing something, but my entire signal chain is protected so room hum doesn't make it in, unless you are talking about the actual pick-ups grabbing room noise... I dunno. I don't see why it can't be solved at the source. ? I don't mean this to be argumentative, I am genuinely interested.

 

[brads4]

I had MAJOR issues with noise with my Jackson and the reason was my CPU that did huge noise interference to my pickups. Eventually had to moce my CPU by two meters This Issue is bigger with passive pickups than active. Monitors might do a lot of damage too.

Were your guitars PROPERLY shielded? AKA completely re-wired with shielding in mind, copper in every cavity, NO GROUND LOOPS (aka no solder on the tops of the pots, 1 path to ground).

 

[mr_fender]

Higher gain = more noise. This is inevitable. Signal clipping is basically a crude form of compression, so the more the signal is amplified and clipped the higher the noise floor gets. You will never remove all of the noise. All you can do is reduce it as much as possible at the signal source. Good guitar and cable shielding is a must and don't use too much gain.

 

[FirstMM]

If by noise we are talking about the hum or hiss coming from the amp with no guitar signal through it then this may be achievable in part.

If two signals come out of the amp, one *with* the guitar input and one without (i.e. just the amp noise) then you could subtract (or invert and add more likely) the noise signal from the amplified guitar signal (this would need to be controllable from no subtraction to 100% subtraction to find the sweet spot).
I suspect that this would still significantly (and adversely) interfere with the end result of trying to get an amplified guitar sounding good though!
It may, however, used in small amounts, help in conjunction with the noise gate.

 

[apescaleconflict]

Were your guitars PROPERLY shielded? AKA completely re-wired with shielding in mind, copper in every cavity, NO GROUND LOOPS (aka no solder on the tops of the pots, 1 path to ground).

Not really much copper or shield and to be honest not so sure how decent the welding was too, my friend did it. I literally suck at electronics, i am colorblind I thought humbucker pickups are not so keen to noise though?

 

[toolfanem]

If your still using the Mayones Regius you should be good on the cavity shielding. My regius is the only guitar I own that is basically dead silent even with absolutely crap power I have in my condo. In fact, I didn't even know how bad the power was until I got my PRS and started walking around my room (which might be something you want to do, walk around the room and see if any "spots" are noisier than others). My CPU and the conduit in my one wall throw off SO MUCH NOISE! But my Regius is crazy silent. Also check if any additional stomp pedals or pus are causing it.

 

[brads4]

Not really much copper or shield and to be honest not so sure how decent the welding was too, my friend did it. I literally suck at electronics, i am colorblind I thought humbucker pickups are not so keen to noise though?

Well there you go. You need to have a properly shielded electronics cavity in order to eliminate noise. My guitars are SILENT. I was in shock how quiet once I did it right. That's what I'm saying noise reduction is a band aid. If you have done all proper shielding and quality electronics, there should be no noise, no matter what room you are in, unless the audio is being picked up via the pick-ups.

Most guitars, even high end are wired to the standards of a high school student. They basically all need to be gutted and done again, (with some high end exceptions!)

 

[brads4]

If your still using the Mayones Regius you should be good on the cavity shielding. My regius is the only guitar I own that is basically dead silent even with absolutely crap power I have in my condo. In fact, I didn't even know how bad the power was until I got my PRS and started walking around my room (which might be something you want to do, walk around the room and see if any "spots" are noisier than others). My CPU and the conduit in my one wall throw off SO MUCH NOISE! But my Regius is crazy silent. Also check if any additional stomp pedals or pus are causing it.

You can shield even a low end guitar no problem. Here's my cavity. 2 Vol, 1 tone, 3 way switch. Railhammer pickups.

 

[Xrocker]

You already have a switch on the AxeFx that eliminates 100% of the noise.
It's the power switch on the far left of the front panel.

It also gets rid of all of your playing mistakes.

 

[FirstMM]

Well there you go. You need to have a properly shielded electronics cavity in order to eliminate noise. My guitars are SILENT. I was in shock how quiet once I did it right. That's what I'm saying noise reduction is a band aid. If you have done all proper shielding and quality electronics, there should be no noise, no matter what room you are in, unless the audio is being picked up via the pick-ups.

Most guitars, even high end are wired to the standards of a high school student. They basically all need to be gutted and done again, (with some high end exceptions!)

I just did a test on my "noisy" presets; I unplugged the guitar cable from the Axe FX to see how much noise was really being generated by the amp sim.
The answer was practically zero for most amps; on some there was a gentle hiss. My conclusion is that amp noise reduction is NOT required but adequate shielding and cabling is.

However, if you stick a m-zone in front of a FAS Modern II then you will get a heap of noise. Personally I just wouldn't do it!