How_to_get_a_tone_that_rocks

"Writing about music is like dancing about architecture"
- Frank Zappa

• Introduction
  • Start-up
  • The RACK
  • Making Our Tone
    • Preamp
    • Noise Gate
    • Compressor
    • The Tonestack: Amp Modeler
    • Cabinet: Speaker Cabinet Emulation

Introduction

Start-up

After the first startup you will see a small head with the following parameters:

• Pregain: input level of the guitar.
• Drive: signal gain.
• Clean / Dist: amount of distortion.
• Master Gain: amount of signal from the pre-amp to the power section.
• Bass and medium boost (presence) and Reverb (with a slider for control the dry/wet ratio of the reverb)
• Convolver: A great function that brings to Guitarix a series of characteristic curves of famous amps/mics and reverbs that can be found on internet (in wav format). For more info, see [Convolution]

“dry/wet” functions found in reverbs, distortions... treat at the same time the “clean” and the “processed” signal regulating the mix between the original and the processed signal, controling the mix between them. “Clean/Dist” is the same for the clean and the distorted signal

But we need more things to process our guitar/bass, don't we? At least our amp “will have” some valves (or tubes) that will give our instrument that “analog-ish” tone...

• 12AX7: this is the main valve used in guitar preamps, famous for being used by Marshall (along with the inimitable EL34 on the power section) and VOX, producing (again with the EL34) the known “british sound”.
• 12AU7: A more modest valve (it only gives a 19% signal of a 12AX7), it was used in some vintage Gibson and Marshall amps.
• 6DJ8: Also known in Europe as ECC88, it has an interesting tale to tell. It was first used in VHF tuners and later in many Hi-Fi amps of the time... other than that I don't know any amp of the usual brands that uses it...
• 6V6: “crystal-clear highs and powerful and defined bass” is what characterizes the “american sound” of Fender amps of the time. Nowadays their, bigger sibling 6L6 is used on the more powerful "Hi-Gain" power stages.

We can diferentiate the sounds in: British sound (powerful mids), vintage (less saturated sound of 12AU7 and 6DJ8) and American sound (greater high and low end response by the 6V6). The remaining sounds of the 0.18 Guitarix version available in the repositories are a mix between them:

• 12AX7 preamp and 6V6 power stage
• 12AU7 preamp and 6V6 power stage
• 6DJ8 preamp and 6V6 power stage

The RACK

To get a nice tone, as in any amp, we have to “turn some knobs”. Guitarix is designed as a modular amp so if we want to make the best out of it we need to add some modules and fiddle with them.

In the plugins menu we click on “show stereo rack”, “show mono rack” (so we can see all the effects we add) and “show plugin bar”. Likewise, we select the tuner in the options menu (we could launch it also from the plugin bar)

If we have already messed the settings, in the same options menu there is the option to reset all the parameters if we don't like how it is all working.

There are many modules that can be added to the rack, for example:

• Amp and cabinet emulation: “Tonestack” and “Cabinet” plugins
• Noise gate already included in the rack: noise gate, noise shaper and limiter included.
• Distortion: Overdrive and a powerful multiband distortion
• Equalizers: low and high-pass filters, tri-band graphic equalizer (like in most common amps), parametric (10 band EQ with frequency and Q-factor controls), even in the distrotion and emulation plugins
• Compressor
• Effects: Wah Crybaby, Feedback, delay, chorus, flanger, reverb…

All effect plugins can work pre-processing (normally used to correct a signal) or post-processing (normally used to just improve it). Stereo effects all work post-processing.

Leaving the effects out for now, we'll talk about them later, the main points to get a good tone are the equalization (by emulator and/or equalizers), the noise gate, the multiband distortion (for a great high-gain tone) and the compressor.

Here it comes...

Making Our Tone

Let's try the hardest scenario: we want a metal distortion like they use in hell to be more metalhead than the Painkiller's bike. It means that we have to learn how to fiddle with the amp and the noise gate, something basic in digital emulators. You will see, cheer up!

If afterwards we want a more crunchy classic tone, we will lower some knobs, and if we want something cleaner we will know how to keep it thanks to what we have learned.

To create our tone it is fundamental to control as far as possible the following points:

1. Preamp 
2. Noise gate 
3. Compressor
4. Amp emulator
5. Cabinet emulator

I will start hard so you don't lose interest. The 2nd and 3rd points are the most complex but also fundamental, specially compression. Don't panic: practice, read and re-read all the times you need until you understand because it is something you'll need with any instrument and in all studios, home or not.

Preamp

As we seek a powerful tone first we need to protect our ears so we lower the master gain (know usually as "post-gain") to the minimum (-20dB). Now we drive hard the preamp so the valves distort: Pre-gain, drive and Clean/dist to the max. Don't get alarmed, it probably sounds awful. Now click the bass boost and the presence switches. Does it sound Better?

When we look for a less saturated sound (70's hard rock for example) we'll experiment with the settings of Drive and Clean/Dist. As soon as we get a tone we like we can turn up the Master Gain.

Try to avoid clipping the sound when you modify the preamp because it could be misleading. In principle, we only modify the pre-gain if the incoming signal (from the guitar directly or via pedals between it and the soundcard input) is too high.

Noise Gate

• Noise gate: It cuts not-desired signals. The wheel controls the threshold, i. e. if a signal crosses this trheshold it gets cut. If we we overdo it it will starts working even as we play. You can test it turning it to the max and playing a sustained note. You'll see how the noise gate cuts the note quickly.

The gate can be so brutal that it can interpret a strong left-hand vibrato as noise, so use it sensibly. Sometimes is better to use a little less gain (or the next control in the noise gate, teh noise shaper) if you want a powerful but round tone (amps add buzz from gain values of 7 or 8 upwards killing your dinamics).

• Noise shaper: It acts against the general noise in the signal, cutting out some of the “buzz” that comes with digital distrotion. It is very useful to lower the not desired gain without messing up other controls.

In my case, if the noise shaper is set very high, a loss of brightness in the instrument is noticeable. It is not very importatnt but it is something that we'll have to amend later with the equalization and what starts good it stays good.

• Mono level out: It controls the ouput of the noise gate. If our gain is so high that it even clips in the moise gate this little one will lower the singal up to 20 dB. You can have terrific results with huge distortions and then lowering 10 or 15 dB with the mono level out. Be warned though, you might be accused of lack of naturalness.
• Clip: It sets a limit to the signal output, and it does not allow your guitar to exceed it.

Learn more about the Noise Gate

Compressor

Controlling the dynamics of the guitar or bass can be (in fact it is) very important, and doing it well will give some “punch” to our tone. In musical production it is necessary to control it.

So far so good, What does Guitarix's compressor offer and what can wed o with it?

• Knee: Controls the transition from the original signal and the compressed one.
• Ratio (Compression ratio): It controls the amount of compression (reduction) applied to the signal. It is written X:1 and it is measured in dB.

For example, if we had a 6:1 ratio the signal that exceeded the threshold by 6dB would be compressed to 1dB above the same threshold. If the signal exceeded it by 18dB it would be compressed to 3dB above it.

• Threshold: It is the point from which the signal is compressed. Everything below this level will not be affected.
• Attack: it is the time that takes the signal to be compressed starting at the time it exceeds the threshold. Low values usually are between 50 to 500 microseconds and high values between 20 to 100 miliseconds.
• Release: It is the opposite to the attack. It is the time that the compressor takes to go from a compressed signal to a signal below the threshold.

The right values depend on the instrument and each one's way of playing. Usual values fro guitar are 5:1 ratio and 5 to 10ms attack. For bass similar attack values and a ratio of 8:1 are used.

Learn more about the Compressor

The Tonestack: Amp Modeler

Not many things to explain about it: several amp models along with a 3-band equalizer (low, med and high). You have to fiddle with the little knobs and, you know, if you want the bloody Metallica tone plenty of lows, few mids and some highs.

In my case, I choose a Mesa Boogie, set the equalizer on 0,7-0,5 and 0,3 and switch on the tonestack on the left switch.

The volume has been somewhat lowered by switching the tonestack on so up with the master gain to 0dB (it was on -20dB) and I already have a typical rocky sound of the Mesa.

Well, I will screw you a little bit with this line: now switch off the presence control on the head. It sounds like “crunching a snack package”, doesn't it? Then switch on the cabinet module and you'll see how fast it improves. What were you thinking using an amp without plugging it to a speaker?. Now you know how the “line out”Italic text of an amp sounds like.

Learn more about the Tonestack

Cabinet: Speaker Cabinet Emulation

Each cabinet will give a different tone and the low/high controls will affect the sound. Remember that there is an extra volume potentiometer in this module.

Learn more about the Cabinet Module