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ME-50B: Bass Multiple Effects

A Bass Player’s Dream Come True.


The BOSS ME-50B puts world-class bass effects in a rugged floor unit with easy pedal-style control. Effects are divided into six sections—Compressor/Limiter, Master, Filter/Tone, Drive/Synth, Delay/Modulation and Expression Pedal—giving bassists a range of unique and powerful tones including new effects like Sound Hold, Octave Up and Kick Drum. Effects can be edited using 23 knobs and controlled via three built-in footswitches and an assignable expression pedal. This is the piece no bass player should be without!

  • Floor-based bass multi-effects processor with easy analog control
  • Killer COSM Compressor/Limiter and Drive effects, plus T-Wah, Slow Gear and Defretter
  • Innovative Sound Hold function for sustaining a low note while playing on top
  • Sound On Sound recording with new Kick Drum effect for keeping time
  • Dedicated knobs for each effect section—no menu-surfing!
  • Easy Tone effects with Preset EQ templates for quick tone editing
  • 3 footswitches and onboard expression pedal routed to 6 options like Octave, Wah, etc.
  • Solid metal case built to withstand abuse

A Bass Player’s Dream Come True.

More Info

Multi-Effects Made Simple

BOSS understands that bass players want access to powerful effects, but they don’t want to get caught up in the menus and programming hassles of a multi-effects processor. Enter the ME-50B. Just like its guitar-oriented sibling, the new ME-50B puts BOSS’ finest multi-effects for bass into a convenient floor processor with the feel of a compact pedal. Forget about menus and cursor buttons. Just reach down and twist a knob!

Independent COSM Compressor/Limiter and EQ

Everyone knows that the fundamentals of good bass tone are compression and EQ. That’s why the ME-50B features two dedicated sections for these essential effects. The Compressor/Limiter uses advanced COSM modeling—including a “Natural” compression setting that retains the nuances of your playing—to give you tight, punchy tone. Simply select the compressor “Type” and adjust the Sustain/Threshold knob to get the tone you want. The Master section includes a 3-band EQ with a sweepable mid for precise tonal shaping.

Get Creative with Cool Filter/Tone Effects

The ME-50B includes a variety of unique tone-shaping effects just for bass. These include a handy “Octave Up” effect, which adds a note one octave above the original while retaining your natural bass sound—complete with adjustable drive on the octave-shifted note—plus favorites like Slow Gear, T-Wah and a Defretter effect for instant fretless sounds. Using the Tone effect preset, you can get quick tonal variations with preset EQs like “Bottom Boost” and “Mid Shape.”

Incredibly Warm Overdriven Sounds and More

Want some extra bite? Switch on the ME-50B’s Drive effects, which include settings like “Muff Fuzz,” “Bass Driver,” “Natural” and “Metal” to give you a range of overdriven/distorted sounds. A new “Hi Band” effect creates a distorted sound on the high frequencies while keeping the lower frequencies intact—perfect for creating complex tones while keeping your original playing dynamics. There are also four synth bass sounds with superb tracking and natural feel.

Sound On Sound with a Twist

Sound On Sound recording is very popular with guitarists, and now bass players can build their own loops, too. But the ME-50B can do even more. Using the new Kick Drum function, players can tap in their own kick drum and create loops over the beat. If that’s not enough, check out the new Sound Hold function, which lets you endlessly sustain a low note while playing over it. With the ME-50B, bassists can take their playing to a whole new level.

A Bass Player’s Dream Come True.


AD Conversion
24 bit + AF method*
DA Conversion
24 bit
Sampling Frequency
44.1 kHz
24 (user)
Compressor / Limiter
Filter / Tone: T. Wah, Octave (Up / Down), Slow Gear, Defretter, Enhancer, Bottom Boost, Mid Shape, Hollow
Drive / Synth: Overdrive / Distortion, Bass Synth
Delay / Modulation: Delay, Phaser, Flanger, Chorus, Reverb
Noise Suppressor
Master EQ
Effects for Expression Pedal: Foot Volume, Wah, Resonance, Bend (+1 OCTAVE, -1 OCTAVE), Sound Hold, Kick Drum
Nominal Input Level
INPUT: -10 dBu
AUX IN: -10 dBu
Input Impedance
INPUT: 1 M ohms
AUX IN: 100 k ohms
Nominal Output Level
-10 dBu
Output Impedance
2 k ohms
7 segments, 1character LED
INPUT jack
OUTPUT jacks L (MONO)/ R
AUX IN jack (Stereo Mini type)
AC Adaptor jack
Power Supply
DC 9 V: Dry batteries (R6/LR6 (AA) type) x 6, AC Adaptor (PSA series: Optional)
Current Draw
140 mA
Owner's Manual
Dry Batteries (Alkaline: LR6 (AA) type) x 6
AC Adaptor: BOSS PSA series
Foot Switch: BOSS FS-5U
Dual Footswitch: BOSS FS-6, BOSS FS-7
Size and Weight ( incl. batteries )
384 mm
15-1/8 inches
225 mm
8-7/8 inches
78 mm
3-1/8 inches
3.2 kg
7 lbs.
* 0 dBu = 0.775 Vrms * AF method (Adaptive Focus method) This is a proprietary method from Roland that vastly improves the signal-to-noise (S/N) ratio of the A/D and D/A converters.
*The specifications are subject to change without notice.



Dual Footswitch


Two switches in one, BOSS’s FS-6 combines latch- and momentary-type switching into one unit.

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Dual Footswitch


Compact, multifunctional dual footswitch for remote control of effect pedals or amp channel switching.

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If you have questions about operating your Roland, BOSS or Cakewalk product, please check our Knowledge Base for answers to the most common questions.

You can also contact our Product Support department by phone or email.

In addition, we have a library of Support Documents that you can download and reference. If Support Documents are available for this product, they will be listed below.

Support Documents

BOSS Product Catalog 2008
Forging the Future - Innovation for Creative Inspiration
BOSS forges into 2008 with an awe-inspiring lineup of effects, digital studios, and accessories.
Guitar Effects Guidebook Vol. 20
ME-50B TurboStart
ME-50B Brochure
BOSS Product Catalog 2014
BOSS Product Catalog 2012
BOSS Product Catalog 2011

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