Controlling and Tightening Up Bass in your Amp/Cab Tones

Scott Peterson

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I've done something for ages (with EQ pedals, parametric EQ, people use Dirt Pedals for this, etc.) in real life (IRL) and the digital world using Pre-EQ before the amp block.

This isn't just an FM3 'trick' - you can do it on any Fractal device. I've been doing dating back to the original (Cliff handbuilt in his garage!) Standard (though, with a PEQ block).

Fractal does a cool thing where there is an independent dedicated parametric EQ on the amp's input block. Because Fractal is smart. LOL.

Some amp models will show you the 'secret' like the Friedman models or the Vox AC30 models - it is already in use. So it isn't some big secret, but many players don't know or understand it. This was a super popular thing to do in the '80s for high gain sounds and works well on Fender cleans and Mesa Rectifier type gain. It's pretty universal.

Just go to the amp block and then the "Input EQ." On the Low Cut (aka, "High Pass"), dial to taste. I'll typically start around 100Hz and then move it up or down to taste.

HighPassFM3.png

If you are apprehensive about using this before you try it, you'll lack 'oomph' 'thump,' or the bottom end is unfounded. You'll control the 'bloat' 'mud' or whatever negative term it is you use. Your bottom end will be there; you are just 'tightening it up.'

Try it and trust your ears.

Have fun!
 
I was trying this... this morning before reading your post. As well, turning down the Hi-Cut seems to tame bright PAFs.
 
A good note about this which is sometimes confusing: Some amps you open up already have settings as motioned. This is because some amps have fixed EQ circuits on their input to do some shaping to the incoming guitar signal. On real amps what the designer chose is what you get, but in fractal amps that's exposed as an EQ you can adjust to taste.

Taming lows and highs, boosting mids, etc are all pretty useful tools which are available to us right out of the box on the input EQ.
 
Right on Scott! This is one of the most powerful parts of the amp block that sadly goes unused. Using the filter, freq and gain- attach a your favorite velocity modifier to the gain, I like the Pitch Follower. When soloing you can pull out some squeak in the upper register or use it to boost and add clarity or snap to pop out a single note riff in the low register.
 
Is there an advantage to setting this in the input block over other blocks, such as the amp or cab blocks?
 
Is there an advantage to setting this in the input block over other blocks, such as the amp or cab blocks?
As I use it and as shown, it is on the input page of the amp block.

You can also use the cab block, it has a page to do a similar thing.

As for advantage or not, try all of it and use your ears.
 
Is there an advantage to setting this in the input block over other blocks, such as the amp or cab blocks?
Scott’s talking about doing this at the input of the Amp block. The advantage of putting the low cut there is the effect on distorted low-frequency sounds.

Distortion produces harmonics. When you distort the low end, the bulk of those harmonics fall in the low midrange (some engineers call this the “mudrange,” because that’s where muddy sound lives). By taming the bass before distortion, you minimize the mudrange harmonics, and the bass gets less flubby.
 
Scott’s talking about doing this at the input of the Amp block. The advantage of putting the low cut there is the effect on distorted low-frequency sounds.

Distortion produces harmonics. When you distort the low end, the bulk of those harmonics fall in the low midrange (some engineers call this the “mudrange,” because that’s where muddy sound lives). By taming the bass before distortion, you minimize the mudrange harmonics, and the bass gets less flubby.
It is also possible to do the '80s distortion thing a lot of us used to do with outboard gear and analog amps; pull a bunch of mids before the amp and then crank them back in after (used to use an EQ pedal). Stryper used to do this among others. Very popular with Rocktron and ADA-1 users too.

What I am doing when I do this is what Rex describes - he's just better at describing it than I am. LOL.

I used to use a Gil Ayan "Smooth and Slim" pedal that was a highpass filter before Fender (and Fender type preamps ala Mesa); loved that thing. Similar thing, all with the same goal - cut the flabby lower mids and loose bottom.

It is just personal taste and preference in the end. If it works for you, Fractal gear just allows you to shape things almost magically if you stop to ponder it.
 
Is there an advantage to setting this in the input block over other blocks, such as the amp or cab blocks?

Just a different approach to tone shaping. An analogy would be Mesa Boogie's Mark series' tone stack being before the distortion. While rolling off the input will not create this kind of tone, the concept is similar; giving the distortion what you want to harmonically enrich. This let's you make the tone tighter or messier more easily.

Let's say you hate the 800hz Boston tone honk. If you cut it out of the input then you greatly eliminate not just the 800hz frequency but all of the harmonic series tones as well that the distortion would create. If you try to do so after the fact on just the speakers then you are trying to cut the octaves and other intervals as well; and then rolling off after the fact on the cabs is going to remove a lot of those upper harmonics the distortion created.

Bla bla bla, sorry for the terrible analogies, hope I got the gist across.

Cheers!
 
My first adjustment is typically the depth knob. I figure if it was important enough to have its own dedicated knob on the AX8 I should probably look there first. Usually lowering that takes care of whatever low end issue I have.

Sometimes I'll try the "cut" switch in the preamp or lower the bass knob. Rarely do I tinker with the input EQ because it's often already been cut (like with Friedman BE amps).
 
Sorry everyone. What l meant to write was input page of the amp block over the cab block. Sounds like by setting the HP in the amp block would be eliminating any problem frequencies before the signal is even processed.
 
Sorry everyone. What l meant to write was input page of the amp block over the cab block. Sounds like by setting the HP in the amp block would be eliminating any problem frequencies before the signal is even processed.
The input EQ is a very different thing here. Just try out on a Mesa Recto 2 Red Modern. It removes a ton of distortion on the low strings as you move the frequency up. Doing this in the cab block acts just like a simple bass cut. Does nothing to gain structure. This is something, that the MARK IIC+ already has in it's main EQ section, where you shape the distortion character, then just the 5 band EQ is basically a normal EQ.
 
Sorry everyone. What l meant to write was input page of the amp block over the cab block. Sounds like by setting the HP in the amp block would be eliminating any problem frequencies before the signal is even processed.

Exactly like @milan.pohancenik said. Another way to test this out would be to put an EQ block before the amp, then after, and move it back and forth to test.

The difference is after the distortion, you're just shaping the sound. cutting a frequency cuts that frequency. In the cab block is just another place that's after the amp to shape the sound.

But before the amp (which inputEQ acts at) you're shaping the sound of your signal as it goes into the amp. As others have said if you cut out low end here, then you remove not just the low end but all the distortion that's applied to that low end so you change the sound up through the frequency range. Boosting treble doesn't just boost a treble frequency but ads more high end content to be distorted which multiplies through your gain stages.

Heck, half of the reason people like or hate different pickups can partly be attributed to whether they have more or less of certain frequencies. It's an indirect input EQ (which also has some feel/etc effects). Also half of the benefit to using a TubeScreamer as a boost with the drive at 0 is that it a) increases the level of the input signal for a bit higher input gain, and b, it cuts low end and boosts mids which tightens up the sound. So you can get a lot of similar affects with more control by tweaking the InputEQ.
 
Exactly like @milan.pohancenik said. Another way to test this out would be to put an EQ block before the amp, then after, and move it back and forth to test.

The difference is after the distortion, you're just shaping the sound. cutting a frequency cuts that frequency. In the cab block is just another place that's after the amp to shape the sound.

But before the amp (which inputEQ acts at) you're shaping the sound of your signal as it goes into the amp. As others have said if you cut out low end here, then you remove not just the low end but all the distortion that's applied to that low end so you change the sound up through the frequency range. Boosting treble doesn't just boost a treble frequency but ads more high end content to be distorted which multiplies through your gain stages.

Heck, half of the reason people like or hate different pickups can partly be attributed to whether they have more or less of certain frequencies. It's an indirect input EQ (which also has some feel/etc effects). Also half of the benefit to using a TubeScreamer as a boost with the drive at 0 is that it a) increases the level of the input signal for a bit higher input gain, and b, it cuts low end and boosts mids which tightens up the sound. So you can get a lot of similar affects with more control by tweaking the InputEQ.
Yeah, the input EQ is mighty. Combine the 2k @ 9dB boost with the bright switch in the preamp and you'll get insane clarity, that is sometimes missing in the amp models. But Fractal always gives you the possibility to add it. If you don't like it, don't add it. I love this gear! Also there's the possibility to put the output EQ between preamp and power amp and make some goodness there. Just another option of thousands.
 
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