The Keeley Compressor Pro is a studio-grade compressor built into a pedalboard-friendly stompbox, with the kind of metering and control set you’d normally only find on a rack unit. It also works just as well on vocals, bass, or a full mix as it does on guitar!
Studio-Grade Compression, Not Just a Guitar Pedal
Most compressor pedals give you a knob or two and leave the rest to chance.
The Compressor Pro gives you the full control set of a proper studio compressor: Threshold, Ratio, Attack, Release, and Gain, plus switchable Knee character and an Auto mode that reads your playing and sets Attack and Release for you. It really is that good!
The 7-segment LED bar shows the level of gain reduction in real time, so you’re not guessing.
Because it accepts a wide input range and tracks RMS level (not peak), it works as well on a full band mix, a vocal, or a drum machine as it does on a guitar or bass.
, to add polish and sustain in the studio, or to keep podcast and video audio levels consistent without having to babysit a fader.
Key Features
- 7-segment LED display showing real-time gain reduction, from -1dB to -20dB
- Bi-colour Threshold LED indicating exactly when compression engages and releases
- True RMS signal detection, tracking the actual level of your input rather than just peaks
- Switchable Hard Knee (for limiting or heavy sustain) or Soft Knee (gentler, more natural compression)
- Auto mode sets Attack and Release times automatically based on what you’re playing
- Works with guitar, bass, keys, vocals, drum machines, or as a studio/podcast compressor on any line-level source
- True bypass — no tone or level change when off
- Made in Oklahoma, USA
Controls
- Threshold: sets the level at which compression kicks in. Turn it down (counterclockwise) until the Threshold LED turns red as you play — red means the signal is being compressed, green means it’s passing through unaffected. Range runs from -50dBu to +10dBu, covering everything from a passive guitar pickup (around -25dBu) to professional studio line level (+4dBu)
- Ratio: sets how hard the compression squeezes, from 1:1 (no compression) up to infinity:1 (hard limiting, where output level can never exceed the threshold no matter how loud the input gets)
- Attack: sets how quickly compression engages once the threshold is crossed, from 0.15ms to 150ms
- Release: sets how quickly compression lets go once the signal drops back below threshold, from 0.1s to 3s
- Gain: make-up gain to restore level lost to compression. Doesn’t affect Threshold, Ratio, Attack, or Release — up to +20dB available
- Knee switch (Hard/Soft): Hard Knee applies the set ratio abruptly once threshold is crossed. Soft Knee compresses more gradually around the threshold point, generally sounding more natural and lively on guitar and other dynamic instruments
- Auto switch: when on, sets Attack and Release automatically based on the input signal, adapting in real time to whatever you’re playing or recording
Dialling In Specific Sounds
The wide control range means the Compressor Pro can do genuinely different jobs depending on how you set it. A few starting points:
- Smoothing out inconsistent playing or singing: Auto on, Ratio around 2:1 to 4:1, Threshold set so the LED bar shows 3-9dB of gain reduction, Knee set to Soft.
- Adding sustain to guitar or keys: Ratio around 10:1 or higher, Threshold set so the LED stays red roughly half the time you’re playing. Try both Knee settings — Soft tends to sound more transparent.
- Chicken-pickin’ style compression: Ratio 5:1 to 10:1, Release fast (0.5-1s), Attack fast (10-50ms), Threshold set for 9-12dB of gain reduction. This combination deliberately produces the audible pumping and breathing character associated with that style.
- Punchy, controlled bass: Ratio 6:1 to 10:1, Threshold set so the -12dB (and sometimes -20dB) LEDs light up while playing, Knee set to Hard, Auto on. Try Soft Knee too for a different feel — this setting tightens up boom and adds punch to slap technique.
- Hard limiting to prevent digital clipping: Ratio all the way to infinity:1, Knee set to Hard. Adjust Gain against your recording device’s clipping indicator to guarantee you never overload it.
- Speaker/PA protection: Set up as a hard limiter as above. If you’re still hearing distortion from your sound system, reduce Threshold, increase Ratio, and reduce Gain until it clears.
With Ratio set to 1:1 (no compression at all), the Gain control alone turns this into a clean, transparent boost for pushing an amp or another pedal harder.
All in all a super flexible pedal. One you didn’t know you needed – but you do!
Power
Runs on a standard 9V DC centre-negative supply and draws 50mA.
Who Is This For
Worth a serious look if you want to add a bit of studio class to your mix or playing. Equally useful for guitar, bass, vocals, drum machines, podcast recording. Also use it as a hard limiter to protect your amp or PA from overload. ( but prpbably a bit wasted just using it for this
Watch The Keeley Compressor Pro In Action
FAQs
It’s a studio-grade compressor and limiter in pedal form, with full Threshold, Ratio, Attack, Release, and Gain control, real-time LED gain-reduction metering, and switchable Hard/Soft Knee compression.
A standard 9V DC centre-negative supply at 50mA.
True bypass — no tone or level change when the pedal is switched off.
Hard Knee applies the set compression ratio abruptly the moment the threshold is crossed. Soft Knee compresses more gradually around that point, generally sounding more natural and lively, particularly on guitar.
It sets the Attack and Release times automatically based on your playing or input signal, adapting in real time rather than needing manual adjustment for every source.
Yes. It accepts a wide input range and true RMS level detection, so it works equally well on bass, keys, vocals, drum machines, or as a general studio or podcast compressor.
Reviews
There are no reviews yet.