Sound Engineering the Guitar

The goal of this inquiry seminar is to explore the world of guitar recording and achieve a better sound presentation.

Background

Previous Background with Music

I started playing in 6th grade and developed a taste for heavy metal and guitar focused songs. This includes Canon Rock by Jerry C, Cliffs of Dover by Eric Johnson, Jordan by Buckethead, and Scarified by Paul Gilbert. Unfortunately, by the time 9th grade came along I would have stopped playing guitar.

I would re-find the spark in my 3rd year at WPI. I finally got myself a decent digital analog to digital converter. I found myself interested in 90’s and 00’s alternative rock, as well as a lot of Japanese rock music. From then on, I have been making song covers occasionally and uploading to YouTube. As such, I took the opportunity to explore Music through WPI's music catalog.

In D-term of 2020, when COVID-19 terrorized the world, I found myself taking two WPI music classes: MU2300 (Foundations of Music Technology) and MU3615 (Topics In Digital Sound). I was introduced to Ableton, and I finally found a replacement for Audacity for sound engineering. This perhaps was a huge turning point in my career, as I was about to level up the sound quality of my guitar covers.

Motivation

Having gotten into creating song covers and learning the new tool that is Ableton, this inquiry seminar became a way to push my knowledge and ability of both of these skills to the next level. I find myself struggling with EQ and Compression Manipulation, and found it difficult to differentiate between good EQ engineering and poor EQ engineering.

Equipment

• Ibanez Prestige Electric Guitar
• Behringer U-Phoria UMC2-2HD Audio Interface
• DT770 Beyerdynamic Headphones

(From left to right) Ibanez Prestige, Behringer U-Phoria, DT770 Beyerdynamics. The VOX amp is also featured here, but not used throughout the course

Getting the Right Tone

Understanding Amps

For the first part of the inquiry seminar, I explored briefly into some general principles of an amplifier

Tube Amps vs Solid State Amps

Tube amps and solid state amps differ in their methods of amplification. While tube amps are voltage driven, solid state amps are current driven. The general result is that tube amps amplifies greater texture, whereas solid state amps amplifies greater power and detail. From listening to a few examples, the tube amp complements nicely with bluesy styles due to its richer texture and dynamic range, while solid state amps are more suitable for rock or metal.

Impedance

Impedance levels indicate the levels at which sound can pass through. Prof. Manzo's textbook mentions three levels: Line level, Microphone Level, and Instrument Level, ordered by the levels. For example, plugging in a microphone will result in barely any sound, since the impedance level of the microphone is higher than the line level. On the other hand, plugging a microphone into the instrument level will resort in distortion.

Impulse Response

Impulse Response is a way to recreate the sound of a rig set-up. This is done by recording the existing rig into the computer, and using an impulse response software to transform the signal.

Recreating the Tone: Separate Ways

As an introduction to sound engineering, I worked on recreating the sound of the synthesizer from the intro of Journey's Separate Ways in Ableton. I used two sawtooth oscillators in sub-oscillator mode, and I de-tuned the second oscillator to achieve a slight phase effect. Then the signal chain follows through to the Equalizer and the Reverb. For the equalizer, I did recognize the need to control lower frequencies, but failed to recognize the same for higher frequencies. This led to issues with the tone that will be fixed later on.

Into getting a great Guitar Tone

General Guidelines

A common trait seen in teenage guitarists is their affinity to crank up the distortion to the max and rock out with no sense for tone. Of course, I am guilty of this as well in my middle school years. Of course, good sound comes from more than just distortion. Normalization, equalization, and compression are also very big ideas that need to be taken into account. A few guide lines that I learned were

• Normalization is required to make sure the volume is never unintentionally clipped
• Compression should be applied at the mastering stage, after maxing out the volume
• Analog equipment (as opposed to VSTs) can give a ‘warmer sound’. There may be incentive to invest in actual physical gear, rather than just relying on digital effects simulators.

The DT770 BeyerDynamics Headphone

Headphones

One key problem earlier describe was my difficulty in differentiating between good EQ engineering and poor EQ engineering. It turns out that I have been using a cheap pair of headphones with low resolution, and acquiring a professional grade pair of headphones was in order. Some key factors that I found were

• Choosing headphones that are 'Open' or 'Closed'. Open headphones give a more accurate sound of how live speakers should sound like, but closed headphones keeps the sound contained.
• Finding a balance between treble and bass
• Impedance level. Higher impedance headphones offer greater resolution at the expense of greater power requirements. Lower impedance headphones require less power, but the resolution is lower
• For higher impedance headphones, a microphone amplifier may be needed to supply those extra watts. Some of the higher-end audio interface can also offer more power

PositiveGrid’s BiasFX and BiasAmp

As per reccomendation of Prof. Manzo, PostivieGrid's BiasFX and BiasAmp are excellent VST's to help in creating professional grade guitar tones. With these two VST's a complete customization of the signal chain from start to finish can be achieved. It also comes with pre-customized packages, from default presets for a quick ballpark tone to downloadable fully designed signal chains that mimics signature sounds of famous guitarists.

Recreating the Tone: Highway Star

For the first guitar cover assignment I performed a cover of Deep Purple's Highway Star. I would describe Ritchie Blackmore's tone as whiney, powerful, and raw, which was something I tried to capture using only BiasAmp. I paired the SLO 100 amp with the Jazz Clean cabinet to produce my sound.

Recreating the Rhoads Sound

For the second cover, I worked on recreating Randy Rhoads' signature sound in The Blizzard of Ozz. A guitar tone haracterized by its raw distortion paired with the chorus effects to create a very tight and aggressive sound. Where as in Highway Star I had to try to mimic the tone completely by ear, Randy Rhoads' rig rundown was available on the internet, and the Bias Amp and the BiasFx VST's offered the tools needed to make a complete duplicate.

The Rig Rundown

As seen in FigureX, Rhoads' rig consists of a series of MXR pedals which provides various effects, namely distortion, wah, EQ, and chorus. This was achieved by setting up a similar pedal chain in BiasFX.

Then, the chain is connected to two parallel Marshall Lead 100 Amps, which once again can be recreated in BiasAmp

Mr. Crowley

For the first Randy Rhoads' song to cover I went with Mr. Crowley. A feature that stands out is Rhoads' is the use of chorus, which gives the guitar depth, as if multiple guitars are playing.

Crazy Train

Having achieved a reasonably similar sound to Rhoads, I moved on to a cover of Crazy Train. However, because the solo features a lot of tapping, hammer ons, and pull offs, it was vital that the signal chain provide the necessary power to get a whole and powerful sound.

Compression

As explained earlier, compression is a major part of sound engineering. Compression, or dynamic range compression, is the process of leveling the dynamic range of audio through amplifying quiet sounds and/or reducing loud sounds. There are four main types of compression:

• Voltage Controlled Amplifier - The most commonly used compressor. It is associated with the attack/release/threshold/ratio controls
• Optical - Operates using a light dependent. The dynamic ranged is controlled non-linearly, which can give a smoother compression.
• Field Effect Transistor - Very often used for guitars. Has fast attack times.
• Delta Mu - A compressor whose compression can be described as 'smooth', 'thick', and 'creamy'

1176 Compressor

The 1176 compressor is an FET compressor and was one of the hallmark compressors of the rock and roll era. BiasFX has a compressor which is 'inspired by' the 1176, which became my compressor of choice.

This is BiasFx's Tube Compressor, inspired by the 1176 Compressor

As a general guideline for compression with the 1176, starting with these settings is reccomended:

• Set Attack to 4
• Set Release to 7
• Make sure GR is not more than -3db
• Make sure Pre-AMP and Output is not hitting the red.