Removing bad frequencies from electric guitar

Question

I use the channel EQ in logic to find out bad frequencies and then decrease their levels. For example, the constant hissing noise at high frequencies etc. I just form a peak and move it along the frequency axis to find out bad frequencies and then cut them off for a good guitar tone (especially in high gain). I do this even while just playing although it causes some unnoticeable latency.

But how is this done in processors and pedals? The processors I have seen only have a basic band EQ option which can only adjust the total treble/bass/middle. Do the amp models in processors automatically avoid such frequencies?

P.s. I'm trying to move to processors as it's difficult to switch patches while playing live with a laptop and interface.

Answer 1

Some multi-FX processors have parametric EQs that will allow you to sweep a peak (or trough) in the way you describe. Here's an example from the (manual of the) Zoom G3:

If you're not using a multi-fx and are using separate dedicated pedals, you can also get dedicated parametric EQ pedals - the Empress ParaEq is an example.

Do the amp models in processors automatically avoid such frequencies?

Not really - what people tend to do if they're NOT doing a lot of work with EQ is to choose amp and cab models that 'naturally' de-emphasize frequencies you don't want. (This is what people do with real amps and cabs after all - choose them to make a chain that works well with their guitar).

In particular, it's often the cab model that would have a high-frequency roll-off that would reduce hissing sounds.

Another approach to reduce hissing in a multi-effect is to use a noise reduction effect.

Answer 2

If you have a problem with "hiss" in a sound, then it's rarely something that needs to be solved with a narrow frequency peak: you more than likely just need to cutoff highs above a certain point. This isn't something that requires super precise EQing, it can be done on any modern amplifier by simply rolling off the "highs" on a multi-band EQ.

Having said that, it's much preferable to simply find the source of the hiss and fix that part of your signal chain. It's absolutely not universal that a guitar should hiss when plugged into an amp, especially since you said you're not using any stomp boxes yet. Some noises are the eternal plague of the guitarist (60 cycle hum) but hiss isn't one of them... Perhaps its coming from your laptop setup as it is at the moment, and therefore will no longer be an issue once the laptop isn't part of the signal chain? At the end of the day, there is no way to remove hiss without simply killing some of your highs, which (especially for shimmery clean sounds) is not something you really want to be doing. (But if you really have to, you don't need a parametric EQ to do it)

Why else might you need a parametric EQ (rather than a multi-band common on most amps an a lot of pedals). Usually to tame narrow peaks at specific frequencies are caused by resonances and recording artefacts: but these don't need to be attended to in a live situation: in the incredibly rare situation you are having a weird resonance which you'd fix on a recording through EQ, you just move your amp! Similarly, if you're getting a frequency skewed sound coming through the PA, mic your CAB correctly, don't try and EQ it out!

If there's something I've missed that means you really need a parametric rather than a multiband EQ, then I'm sure there are digital pedals out there that offer it, but as to why it's not included by default on amps/effects processors? It's not generally something a live guitarist needs, and it's much more fiddly and less intuitive than a multiband EQ.

Answer 3

While an EQ can be used to filter out noise, it can become impractical. For example, when you have noise that also has its harmonic frequencies present (60Hz, 120Hz, etc). I personally prefer to use EQ for tone shaping rather than noise management.

There are other solution for managing noise. I posted the following in another thread and copied it over here:

When you have a hum or buzz that is eliminated or affected by touching a metal part of the guitar, this is most likely caused by a grounding issue.

The remaining hum could come for several sources:

• Single coil pickups will by their very nature pickup 60Hz hum (And it’s harmonics). This is a type of inducted noise.
• Electical noise from dimmers, fluorescent lights, A/Cs and compressors (just to name a few sources) as well as RF frequencies in the environment are another type of inducted noise that pickups or tube amps can receive and inject into your tone chain
• The higher your gain setting, the more sensitive your rig becomes to inducted noise. Even humbuckers will pick up inductive noise especially under very high gain scenarios.
• Conducted noise sources include things like ground loops, noise that enters the system trough a noisy power source and noise added by components in your signal chain

Using a multi-meter with a continuity test function you should be able to easily track down any grounding problem within the guitar itself.

As for the rest of the noise, this is tougher.

First, if a guitar is not shielded, noise can enter through the pickups as well as the wiring, pots and switches in the control cavity. Your guitar is essentially a giant electromagnetic antennae. Shielding the control cavity can provide a good amount of noise reduction. Shielding pickup cavities can provide a small amount of reduction but is far less impactful than shielding the control cavity. If the only wire in your tremolo cavity is a ground wire, shielding the tremolo cavity will have no effect. ALL SHIELDING MUST HAVE CONTINUITY TO GROUND IN ORDER FOR THE SHIELDING TO WORK.

Next, getting a good noise suppressor will help. Note I said suppressor not gate. There is a difference. Noise suppressors include both a gate and a filter whereas a noise gate only includes the gate. A good 2 connection suppressor will take a lot of inducted noise out of your tone. Examples of good noise suppressor include the Boss NS2 and my personal favorite the ISP Decimator G String. The only Decimator you want is one of the G series... either G string for a pedal or Pro Rack G for rack. You need to go through the noise suppressor to your amp input, then connect it into your amps effect loop. This will make a big difference in the inducted noise in your signal.

Next for conducted noise get a good power conditioner for your effects and peripherals. You should not connect your amp to a power conditioner. Modern amps use variable power consumption which a power conditioner may have problems with. For the amp, there are ground isolators like the HummX or one made by Logsdon (cannot remember the name). If you want to go really crazy there are isolation transformers like those used for sensitive medical equipment. These are expensive and heavy.

Never, ever use a ground lift as a permanent solution to grounding problems! You are playing Russian Roulette if you do. Ground lifts are fine for diagnosing problems, but they are not a permanent solution!