Anybody try out the new noise reduction pedals?

[Steve A.]

I was just reading about the ISP Decimator and the Electro-Harmonix Hum Debugger, and it looks like these pedals have moved past the noise gate designs of old, and are actually removing the 60hz noise component from buzzy signals. Both of these pedals retail for about $150, but what sounds very interesting is the ISP rackmount model, which uses two different channels of noise reduction- the first goes between the guitar and amp and the other goes in the FX loop (the guitar signal triggers both channels).

The samples I've heard sound great, but there seem to be mixed feelings as to whether either of the $150 pedals color your sound. (I believe that the guy behind ISP used to design the Hush line of noise reduction boxes for Rocktron.)

Thanks!

Steve Ahola

[Mark Hammer]

The eternal problem with pedals/devices that have to make a "decision" about what to do with your signal based on the signal's present properties is that it takes time to make a decision, and sometimes even more time to make the most valid decision.

As such, gate-type devices have always had the challenge of make that decision fast enough so that the initial attack of a note is not lost, and so that noise doesn't leak in during the last few dying gasps of the note.

It's certainly not impossible to do it pretty transparently, but the challenge is still there. When the challenge is not met, that's when you get what Steve calls "coloration". I understand what he means, but will simply note inpassing that "coloration" is a term most often applied to contexts where there is a tonal change brought on by either adding harmonic content, or by "tone-sucking" and loss of some spectral content. Here, there is no real tonal change. Rather, there is a general amplitude change, which in some instances (e.g., loss of the initial attack where most of the harmonic content lives) can appear to result in a sort of tonal change. Small semantic point, but worth noting anyways.

The unit you describe (where the gating action occurs in two places. contingent on the signal properties at the start of the signal chain) is a smart piece of work. Certainly, the most reliable and easiest "decisions" to be made about the signal can be made immediately after the guitar. However, noise accrues across the signal path, from pedal to pedal. The smart thing, then, is to make the decision at the outset and apply that decision further downstream, at the same time as cleaning up the input signal enough to facilitate optimal processing throughout the signal path before the signal gets to that second gating point. It's a bit like raising your kids right when they're young so that the inevitable discipline problems are generally easier to manage with a lighter touch when they're in high school.

The intriguing thing, of course, is that the nature of the noise "problem" changes depending on where you are in the signal path. For instance, a big chunk of the nonmusical part of the signal at the input will be hum, whereas cumulative hiss starts to be a bigger deal downstream as gain gets added to the bits of hiss coming from pedals nearer the start. In essence, you need to adopt different strategies to eliminating the nonmusical parts depending on where the noise-reduction device is going to intervene.

[Steve A.]

...As such, gate-type devices have always had the challenge of make that decision fast enough so that the initial attack of a note is not lost, and so that noise doesn't leak in during the last few dying gasps of the note...
The unit you describe (where the gating action occurs in two places. contingent on the signal properties at the start of the signal chain) is a smart piece of work. Certainly, the most reliable and easiest "decisions" to be made about the signal can be made immediately after the guitar. However, noise accrues across the signal path, from pedal to pedal. The smart thing, then, is to make the decision at the outset and apply that decision further downstream, at the same time as cleaning up the input signal enough to facilitate optimal processing throughout the signal path before the signal gets to that second gating point...

Mark:

I guess I should have posted some links so that you can listen to the sound samples for the ISP products (I don't think I found any for the EH one). My point was that these devices are *not* gates, which will switch off the signal when the sound level drops to a certain point- they actually remove the 60hz component of the noise from the signal. (I would think that they would need a special setting for the UK which uses 50hz instead of 60hz.)

I had wondered about such a device in discussions here about reducing the noise on single coil pickups- it is usually the same goll-darned buzz that I hear from guitars or basses when there are dimmers and televisions on, so why not just remove *that* noise? Of course that would not help if you were receiving the local radio station... LOL

Here is the link to ISP Technologies, with sound samples and a technical explanation that seems to be missing...

http://www.isptechnologies.com/

Thanks!

Steve Ahola

[Mark Hammer]

My apologies, first. I figure that many of the "new solutions" are digital devices, but in my usual style I go on about more general principles unrelated to the pedal under discussion.

[PlayItAll]

I listened to the ISP samples, and while I understand it can be hard to appreciate the Decimator from internet sound samples alone, I'm not sold on it.

It's the same thing I've always felt about NR circuitry - they pros don't outweigh the cons. Something good always gets taken out along with the noise. I think the "feel" of the guitar gets lost. Maybe it's the missing microseconds of attack? Maybe the decay at the end of notes?

Now, if the EHX Hum Debugger doesn't mess with anything except to remove the 60 cycle hum, then that might be worth looking into, but the ISP seems to my ears like a HUSH pedal that has had a lot of caffine. I'm sure players who find the HUSH useful (I used to be one such player) will like the ISP even better. We all know there are times when you have to compromise your tone because of a noisy rig/club/studio etc. but any NR seems to me to be just that: a compromise.

Again, even though I'm a NR "hater" :-) , I would like to demo the EXH Hum Debugger. Wonder how it works... It could be the sort of pedal that would be handy in your gigbag for those nightmare gigs when the hum coming from your amp is louder than the vocalist!

Ed

[01redcobra]

I have one of the floor pedal ISP Decimators. It works as a gate with one knob to controll threshold. It is the only way I can play my Les Paul Jr. without being annoyed with all the noise. I have not had any bad experience with it cutting off the beginning of notes, but it sure does a good job with the noise.

[chipaudette]

I've played the Hum Debugger in the guitar store a couple of times. Unlike all their other pedals (which they keep tucked away in a glass case), they've got the hum debugger already out there in the room with the amps. They've got terrible electrical/RF noise problems so, for every customer trying out an amp, they always pass them through the hum debugger first. That's how I got to try it. Clearly, they trust its sound. That's a fairly solid recommendation there.

Of course, the first thing I did (before even playing) was turn it off. Then I heard all the noise in their building. What a bad place for a store. But, it's Vermont, where their "quaint" mainstreet building is 125 years old. Let's be thankful it has indoor plumbing. So, I decided the noise was annoying and I turned on the hum debugger.

Let me tell you, I was impressed. I am REALLY sceptical of such devices, but I had a hard time finding fault with it. Sure I had a psychological issue with seeing it in my signal path. But, if I set aside my personal bias and was objective and fair, the thing was amazing.

I could detect no noise-gate artifacts. It must be way smarter than that. It must sniff out the AC hum and squash it. To make sure it wasn't too adaptive, I played some long sustained notes. There was no problem. Amazing! As for its transparancy, I was not able to play it in a noise free room. So, I couldn't do an A/B comparison to see how much (if any) tone it may have sucked. But, what I can tell you is that, once it killed the noise, I had a really good time playing the amp. I didn't feel cheated out of any tone.

So, if I lived in a place with a lot of noise issues...or if I gigged around and knew that I might end up in a noisy place...I would have no issue pulling it out of my bag and putting it in my rig.

Chip

[Mark Hammer]

Expect such noise reduction pedals to be a growth industry. Same with hum-cancelling coils etc. As more and more jurisdictions move towards a fluorescent-only policy, the sources of hum will become more numerous. This is not a rant against fluorescent, mind you, just a friendly warning that you don't get something for nothing when it comes to technology, and the move towards more energy-efficient lighting will need to be accompanied by a move towards ways of offsetting the EMI they create. Hopefully, someone will have the "bright" (sic) idea of producing fluorescent fixtures with shielding tailored to reducing hum in audio systems.

[Steve A.]

I have one of the floor pedal ISP Decimators. It works as a gate with one knob to controll threshold. It is the only way I can play my Les Paul Jr. without being annoyed with all the noise. I have not had any bad experience with it cutting off the beginning of notes, but it sure does a good job with the noise.

A noise "gate" will actually turn the entire signal off when it reaches a particular threshold- my impression was that the ISP Decimator would actually remove the 60hz noise component from the signal (with the single control determinining how aggressive it would be in doing that).

Thanks for your report- I think that someone has to actually try one to determine if the compromises inherent in such a design are worth it or not. I have a hunch that it works better for certain playing styles than others.

[Steve A.]

Thanks for all of the comments! I had special ordered the Decimator over at Guitar Center and the rookie salesman looked it up and quoted me a price of $82 plus tax. I hadn't seen them being sold anywhere, new or used, for less than $120 so I figured that was a great deal.

I checked back two weeks later and found out that my (prepaid) order had been cancelled since ISP required that GC buy a minimum of 2 pedals from them. So the store manager gave the okay and they ordered 2 of them. Only when I checked back a week later it turns out that ISP wanted them to buy a minimum of 6 pedals.

So I figure I might as well try out the used Rocktron Hush pedal they had in stock, and the salesman set me up with an amp back-to-back with this guy playing phaser crap that sounded like a bad acid nightmare from the 70's. Jesus F*ckin' Christ- how am I supposed to judge a noise reduction pedal with all of that noise going on??? So I told them to just refund my $89, which kinda pissed them off but what the heck- they *are* The Evil Empire! LOL

Steve Ahola

P.S. As to these pedals changing the tone or response a bit, I've been using dummy coils in some of my guitars, and they change the tone and response a bit (usually compressing the signal a bit because I wire them up in series). As long as the resulting tone is usable and not radically different from the stock tone I'm a happy camper.

I've been using my PRS Soapbar II for live gigs and have had to play all night with the selector switch in the middle position just to keep the noise level down. So I am looking forward to getting an ISP or an EHX Hum Debugger, only I haven't decided on which one to get...