Compressor tips

Try putting the compressor as the the first block in the chain. Compression works better on clean tones than high-gain tones. The following settings are some very basic starting points to achieve some specific sounds.

Axe-Fx scale

The Axe-fx use from 1-10 rather than ms for the attack and release settings. They are scaled in an inverse log relationship to 1 to 1000ms. This was confusing at first because a setting of 10 indicates a faster attack rate which means 1 millisecond. Same thing with release - just remember they are rates and not times. Faster rates mean lower values.

Axe-Fx Setting : Actual Time (attack or release)

1 : 1000ms

2 : 954ms

3 : 903ms

5 : 778ms

7 : 602ms

8 : 477ms

I tend to stay the 9.X range for most things:

9.0 : 301ms

9.2 : 255ms

9.5 : 176ms

9.7 : 114ms

9.9 : 41ms

9.92 : 33ms

9.95 : 21ms

9.97 : 13ms

9.98 : 9ms

9.99 : 4ms

10.0 : 1ms

Note

The compressor will cause some distortion if the release rate is set too high along with a high attack rate. The compressor has been optimized for attack speed as this is what guitar players like. If you set the release rate too high, though, you can get distortion. The proper way to set the release rate is to observe the natural decay of your instrument and set the release rate just slightly faster than that. For the typical electric guitar this is around 3.0.

Compressor settings

Ringy

• THRSH: -17.8dB
• RATIO: 10:1
• ATT: 150ms
• REL: 987ms

This setting is heavily compressed, making chords and single notes thick and even, and sustain like, forever. The medium attack allows the guitar strings to ring, and the long release holds on to produce a massive, Neil Young-like sustain.

Chunky

• THRSH: -15.5dB
• RATIO: 5.1
• ATT: 11ms
• REL: 102ms

This is the fat, ballsy sound that drives many of the guitar-heavy bands of the late ’70s and early ’80s. It’s mildly compressed with a fast attack and a medium release, which allows all the strings - from low to high - to sound evenly for a massive punch. Think "Barracuda" by Heart.

Chicken Pickin’

• THRSH: -31.4dB
• RATIO: 6:1
• ATT: 1ms
• REL: 25ms

Play this sucker on a Telecaster and ride it all the way to Nashville. The fast attack nails the initial string impact, and the fast release lets it go pronto to minimize sustain. The result is a clean, snappy pluck that works great for those blazing cowboy cascades.

Smooth

• THRSH: -27.5dB
• RATIO: 10:1
• ATT: 50ms
• REL: 38ms

This setting is squashed pretty hard with a high threshold that pretty much grabs the entire signal to produce a sound with no sharp edges. The resultant velvety texture is wonderful for smooth jazz tracks and other sophisticated guitar tones.

Dramatic

• THRSH: -30dB
• RATIO: 7:1
• ATT: 250ms
• REL: 250ms

Clean notes that float in languid, ethereal sustain - think Ry Cooder’s brilliantly sparse lines on the Thelma & Louise soundtrack - are provided here. The slow attack allows the note attack to retain punch and impact, and the long release keeps the sound ringing. This expansive and evocative setting works great for slide parts, as well.

Funky

• THRSH: -21.6dB
• RATIO: 7:1
• ATT: 61ms
• REL: 84ms

To accentuate those funky, biting pick attacks - as heard on classic Sly Stone and Earth, Wind & Fire tracks - this medium attack and fast release does the trick.

Adapted from Guitar Player magazine (Aug 2006)

Emulating various well-known compressors

Dyna comp emulation

The MXR Dyna Comp is a classic guitar compressor pedal. From web research, its features were listed as follows:

• Limiting Threshold Adjustable from 4-80 mV
• Compression Adjustable from 15-40 dB
• Attack Time 4mS at center ATTACK setting
• Decay Time 1.2 Sec

To replicate this on the Axe-Fx, use these settings:

• ATT - 9.9 (very fast)
• REL - 1.0 (very slow)
• COMP - 10
• THRSH - -55

By one report, it "sounds more like a Keeley."

Teletronix LA-2A settings

• tube-based electro-optical attenuator
• Comp = soft knee, semi-fixed 4:1 ratio
• Limiting = infinity ratio
• ATTACK TIME: @ 10 microseconds
• RELEASE TIME: 0.06 seconds for 50% release; 0.5-5 seconds for complete release

Universal Audio 1176LN specifications

• FET-based attenuator
• Attack Time: 20 microseconds to 800 microseconds
• Release Time: 50 milliseconds to 1.1 seconds
• Ratios: 4,8,12,20,All
• All-button mode or "British mode": For those that don't know, back in the glory days of gonzo recording, an adventurous engineer wanted to know what would happen if you pressed all four compression ratio buttons in at the same time. It was discovered that with all four buttons pressed in, the 1176 made drums jump out of the speakers, and became a much used staple of hard rock drum recording.

Teletronix LA-3A specifications

• electro-optical attenuator
• Attack: 1.5ms or less
• Release: 0.06s for 50% release