Distortion / Compression / Amp Sims / Post EQ - Some Ideas

Another great post that I had saved for a number of years on my hard drive. I believe this post was originally from the Boss GT forum some four years back. Read, relax and enjoy:

I've been off in my own little world analyzing some things - namely taking apart various distortion boxes, distortion circuits, tube amp circuits and various other little goodies that has been nothing but fun, and time consuming. A couple of things about this post. You may find some of the references a bit “confusing” to you. Please don’t be. This was originally created for the POD XT (LINE6 board) and has been “translated” for the GT6. So some statements embedded in here may not directly apply to posts on this site, even though it seems to reference them. 99% of this material is applicable, though.
I've come up w/ some interesting observations that I thought I'd share w/ ya'll cuz all of this applies directly to the GT6 in some form, or fashion. Secondarily, we need to understand the factors intrinsic to it to get the best out of it.
First, let's tackle distortions in general. One of the things that has come up time, and time again, on this board is the "flabby" aspect of the MESA models - as well as some of the other amps.
Now, that said, let me take a personal experience and add this to the mix. I recently obtained a Marshall MG100DFX (solid state) amp. That thing is as Marshallesque as they come. However, I noticed that when the "Gain" was set to give me that "heavy" distortion and the channel volume was set higher... followed by large increments in "Master Volume" the real amp got very flabby.
Flabbergasted, I grabbed a real JCM800 2x12 from a friend and experienced the same thing - the louder it got, especially w/ higher gain settings on the preamp the "flabbier" the thing got. Transient events (pick attack) and various other things all generally got pushed into the 'mudrange' yielding an overall un-tasteful distortion. A quick trip to my local GC and a few minutes on front of a MESA amp gave me similar results.
So, I went to venerable world-wide web to see if there was any information to assist me in my quest for "tight" distortion and tone. By George, there was one site that had a single comment in it:
quote:

Consequently, it is usual to limit the bass response before the overdrive section.

THIS COMMENT IS QUOTED VERBATIM FROM http://users.chariot.net.au/~gmarts/ampovdrv.htm - A SITE DESIGNED AND MAINTAINED BY GM ARTS...


This got me to wondering, a bit. So I dug through the TS9 and TS808 schematics and, sure enough, darned if the things didn't actually have limited gain at low frequencies (little to no distortion) and much more gain at high frequencies (lotsa distortion).
Similarly, Marshall's MG100DFX amplifiers have a two-leg input network to the distortion section in which the bass/low frequencies are significantly attenuated.
Marshall Bluesbreaker, MXR Distortion+, Marshall Guv'nor, RATT, etc. they all are compensated with high-pass networks with severely attenuated low-frequencies somewhere prior to, or within, the distortion circuits.


So, I grabbed me a "treble booster" type circuit and fed the Marshall off of that... ahh, improvement...


So, I moved onward, in my quest. I bought a few pedals (BOSS Super Overdrive - SD1, BOSS DS1, BOSS BD2, MXR Double Shot, etc). Taking apart these circuits yielded similar information, so we're on the right track.
About 2 months ago in "Guitar One" (I think that's the one) there was one of those small back-page articles on a no-name band. The guitarist from that band was making the following statement about nu-metal sounds:
quote:

You know, the MESA's produce a lot of distortion but they get eGT6remely "tubby", "muddy" and "flabby" when driven to those levels... the other day I was listening to this band that had a killer tone and they were using all MESA's. When I went up on stage, I noticed they were driving the MESA's w/ distortion pedals and their tone was tight, focused and heavily distorted...

So, that got me thinking... so I dug back through years and years of rig info for all my favorite guitarists - Chet Atkins, Brad Paisely, Duane Eddy, Buddy Holly, Randy Rhodes, Jake E. Lee, Zakk Wylde, Eddy Van Halen, Eric Clapton, etc...


One thing became very clear as I focused on the content of these gear rigs - THEY ALL USED EITHER BOOSTERS OR DISTORTION UNITS IN FRONT OF THEIR AMPS... what the hey??? They've got these beautiful Marshalls, and MESA's, etc and they're using cheap ol' distortion boxes???? MXR Distortion+, MXR Distortions, RATT's, BOSS SD1, Fuzzface, etc.


So, I grabbed my Fender Hot Rod Deluxe (all tube w/ crappy distortion) and started plugging in the following chain:


Guitar -> Compressor -> Distortion -> Amp


WOW! What a difference, from flabby, loose and grungy to clear, crisp, clean, chunky, controlled and tight... The Marshall MG100DFX - same thing... JCM800 2x12 unit - same thing. CheckMate 18 Solid State - same... in all cases each of these amps cleaned up immensely and immediately "tightened up..." Even the Guitar Center MESA sounded more like a MESA w/ an MXR Distortion+ feeding a BOSS GE-7...


There are some "tricks" here that need to be noted:

1) If you're going for a more "focused", very "distorted" tone it seems that using the distortion boxes distortion is the way to go, in most cases. The MXR's are very "crisp", very "clear" and very "focused" and "tight" in their tone. This is the EVH, Randy Rhodes approach and it works very well. Different boxes have different characteristics and will yield slightly different results. Those boxes that have more low-frequency content feeding the distortion circuits will yield a slightly "warmer" tone but have a "flabbier" response to them.

2) You can use the box to enhance the amplifier distortions. Much of the "flabby" noise that comes from the amps is due to the power amp draining the power supply. To significantly reduce this, from happening, one must overdrive the preamp a lot more. Thus, you can use the distortion pedal as a booster for the preamp thus taking the load off the power amp - in the GT6 this works the same way. To do that you'd turn down the "Distortion" setting on the pedal and turn up the "Gain" setting. This, effectively, introduces little eGT6ernal distortion to the amp, but allows the preamp to be driven sufficiently hard to clip. Master volume can be set appropriately, then, to drive the power amp less and keep headroom in your power stage for input transients, etc. and it doesn't turn the entire signal to "mush".

3) Older vintage amps and many of the modern tube amps DO NOT have frequency compensation in their distortion circuits. Thus, the entire range of frequencies feeds these areas. Because the bulk of the "power" of the signal is in the low-frequency range, this range becomes the primary range of frequencies, which distort leaving little distortion occurring in the high frequency range. The end result is a "muddy" and somewhat "flabby" tone as the compression that results from the higher low frequency energy is somewhat unacceptable. To compensate this many folks (Eric Clapton, Randy Rhodes, Brian May, etc) used front-end treble boosts of one sort, or another, to attenuate the bass frequencies and produce clarity in the distortion.

Zakk Wylde, for instance, drives JCM800 or Marshall 2203 heads with a BOSS SD1 (Super Overdrive). He uses this pedal for two purposes. 1) As a "gain stage" to drive the preamp a bit harder. 2) For the "bass cut" to "clean up" the distortion coming from his amps. The MXR Zakk Wylde Distortion unit is really a re-vamped BOSS SD1 (which has been in Zakk's arsenal for years).

The other thing to keep in mind, here, is that just because a band uses a MESA, or Marshall, or other amplifier and gets raging distortion out "the amp alone" doesn't mean that it's just from the amp... other things in the signal chain, eGT6ernal to the preamp, can be driving the preamp harder, may be providing some hi-pass filtering, etc... even the internal preamp stages may have been modified, at some point in time, to actually reduce the low frequency content entering the distortion stages. Those are things that we're not privy to, and I'll say, right now, modifications that get made to a lot of amps. Even my friends JCM800, which he bought used and "un-modified" actually had changes made to the front-end to assist the distortions a bit...

Distortion performance varies by guitar plugged into the distortion device (amplifier or eGT6ernal unit). There are ways to "tame" this and provide a more consistent distortion result every time you use the box. To that end, the compressor is the God-send of the distorted guitar.

First, distortion, in general, really works way better when the signal feeding it is somewhat constant. In solid-state distortion units, and even in tubes, you'll notice something IF you really listen. Play a note on the uncompressed guitar and listen to the distortion as the guitar "fades". You'll notice a nice "rounded" distortion at the pick attack... it then decays into "buzziness" and finally "dies away to clean". That second stage of the decay - buzzy - is a result of a bunch of things that can be eliminated/reduced w/ compression.

The goal is, really this: 1) Let the transients through so that you get a feeling of "dynamics" in your playing. 2) Keep the level of the signal up during the "decay" portion of the signal such that the distortion is "fully utilized" and doesn't get to the "buzzy" part of the decay. The compressor CAN do this. A secondary cool part of some compressors (especially the guitar ones) is that they have a high-cut circuit that allows you to add more hi-end, as needed, to "clean up" wimpy distortion.

So, plug the guitar into the compressor... plug the compressor to the distortion, distortion to amp, yada, yada, yada. Then, take the "Attack" setting on the compressor and set this to "Slow" attack. If your compressor reads in ms (milli-seconds) set it for a higher number. On those w/ "Slow / Med / Fast" set the thing to slow, etc.

The "Attack" control determines at what rate the compressor starts to compress. Setting this to a "slow" rate allows transients (pick attack) to go through and compression to start on the "decay" portion of the note. This yields two results: 1) It makes your playing "feel right" in the sense that you can hear varying levels of pick attack clearly. 2) It controls the level of the decay, yielding a better sounding distortion during the longest part of your note. It also allows the tone (initial) to be "brighter" and more "transparent" and "clear".
Then, you can set the "Sustain" control (on many compressors such as the BOSS CS3, etc this controls the "Ratio" AND "Threshold") to whatever makes your style of music sound best.

If you've got some "mud" in the result - increase the "Tone" control to add more treble/edge so that you're driving less bass energy into the distortion circuit. This will "tighten" the tone of the distortion... and you can reduce the "Sustain" some and this will allow a bit more high frequency to pass, as well cuz the bass energy won't be clamping the compressor as tightly.

Last... the output gain control. Setting this up higher will cause your distortion section to distort even harder... set to taste... and voila, lots better distortion with "dynamic response", unlike the distortion you'd get from just plugging a lone guitar into an amp.
On the GT6, I realize, this presents a bit of a problem cuz NONE of the compressors in the thing allow for "Attack" to be set.

With regards to the "Post EQ" dilemma on the GT6. If you read the studio notes (now a part of the new "Guitar Player" format) in some of the magazines (Guitar Player, Guitar One, Guitar World, Recording, Home Recording, EQ, MIX, Sound on Sound, etc) you'll notice that very few recording/mixing engineers saying something like this:
quote:

Gee, when I tracked ____ guitars, I just slapped a perfectly flat mic in front of the guitar amp and recorded it direct to tape without using any EQ or compression. In fact, I even used a transparent mic pre so I didn't color the sound and mess with the track....

For instance, in one of the later "Guitar Player" magazines there's a blurb called "Tracking Zakk Wylde" where his producer is discussing how Wylde gets his tone. It's very clear, and I paraphrase:

"I put an SM57, on-axis, pointed right at the center of the speaker to capture the highs... I put an AKG C421 mic slightly off-axis to the speaker to capture some of the girth of the amp... I then apply a large amount of boost at 110Hz, 220Hz to provide some depth and a large hi-shelf to add some clarity... the mics were run through a Neve channel strip (major coloration) and compressor (even more coloration)."

Zakk has the ULTIMATE tone setup (IMHO only). Les Paul w/ hi-output EMG's into the SD1, to a JCM800 w/ 4x12 cabs loaded with EV12H speakers (yeah, ElectroVoice). His recorded tone is HUGE but his stage tone isn't so great. It's cuz a liberal amount of post EQ was added to the actual amp tone (just like we need to w/ the GT6).

In any studio configuration we have a plethora of instruments that all need sonic space. The actual guitar has tones that range from approximately 80Hz to 1280Hz. A guitar is good for 12 harmonics and that puts the final frequency, 24th fret, 12th harmonic, at approximately 15kHz. Quite a range... As you can tell, that's going to "interfere" with voice, keys, bass guitar, drums, backup vocals, accordion, lute, piccolo and every other instrument on that nu-metal track.

A recording engineers job is to "capture the tone". So, as a recording engineer my job is capture a 150dB SPL amplifier WITHOUT distortion on tape, or hard disk, a goodly portion of the room and several different "perspectives" of that amplifier tone (using different mic's, ambient mic's, etc). All of this must be as "clear" as possible.

Once the basic tones are captured using various mics and they're all "on tape" then the mixing engineer comes in. The job of the mixing engineer is to "make everything fit". Sonically, all the instruments are all over the map and stepping over everyone. The mixing engineer then uses panning, compression, EQ, delay, reverb, chorus, flanging, level, etc. to "separate" the elements, control their levels, enhance their apparent position and allow each instrument its sonic space. In some cases EGT6REME levels of EQ are used - boost and cut. In other cases, the recording engineer has already done this and printed the signals "hot to tape". But, the end result is, many cuts/boosts have to be made to each instrument to get them all to fit - very few do on the first pass.

After the mixing engineer gives the space, clears up the mix and gives everyone the sonic space the neGT6 step is Mastering Engineer. The mastering engineer does several things:

1) Creates the sequence of tracks that makes the most sense - both in terms of levels, sonic content/material, keys, etc.

2) Creates a "glue" that allows a certain sonic element to "bind" every track so that it all sounds like it was created at the same time. If different studios were used to record/mix and a different balance of bass / mid / high is used on each track mixed, the mastering engineer will "balance" these so they're more consistent among the tracks. They may even add a light dash of the same "reverb" to each track in order to add more "coherence" to the final product.

3) EQ's the entire mix for a certain "sound". Country has a boost around 80Hz about 1 octave wide and another around 8kHz 1 octave wide... a bit of "thump" and a bit of "presence". Rock is more mid-range... Jazz is "flatter" w/ a slight roll off at the bottom end, etc.

4) Tames any final elements in the mix that need taming (i.e. wild transients, etc).

5) Compresses to get a "radio friendly" mix...

6) Makes it loud - which I, personally, have some disagreements with.

7) Creates the final copy...


All of those elements are changing the guitars tone. EVH's early sounds, for instance, were not only based on mic elements, post EQ, console coloration, mix EQ and mastering EQ but also the fact that the original signal was delayed slightly and panned Left and Right.
Randy Rhodes sound, for instance, wasn't just a single take. Rhodes would play the solo sections at least 3 times. The best take was panned center and loud. The other two takes were panned L/R and about 6dB lower producing a natural chorus effect. There were other elements of the Randy Rhodes tone including being recorded in the basement of a stone castle... the amps were in a stone room direct mic'd (a large diaphragm condenser and an SM57) along w/ two other large diaphragm condensers located in a stone stairwell - one at the doorway and one further up the stairs. All 4 mics were mixed to create a composite tone, sent through a NEVE console with EQ applied (coloration from the NEVE alone PLUS EQ), into an LA2A compressor and finally to tape - which was then re-EQ'd during the mix-down stage.

The other thing about Rhodes sound on the tape... Rhodes guitar was recorded direct to tape and the tape output (considerably hotter) was fed to the effects chain/amp! This produced a LOT different tone than that of the guitar fed directly into the amp.

What I'm trying to point out, here, is this: We've all made a lot of comments about the GT6 requiring a POST EQ. This is a direct recording device... in a real recording environment POST EQ is DONE DURING MIXING NOT DURING TRACKING. Printing hot to tape yields less than happy results, many times. Understanding the process is key to utilizing the system correctly.

Anyway... those are some things that I've learned in the past few months that I thought I'd share w/ ya'll.
Dar