BOSS ME-50B rear view
BOSS ME-50B front top view


Bass Multiple Effects w/ COSM

Product Highlights

  • Floor-based
  • Bass Multi Effects w/ COSM
  • Easy analog control
  • Premium COSM Compressor/Limiter & Drive effects
  • Innovative Sound Hold feature
  • Designated knobs for each effect section
  • No complicated menu navigation
  • Three footswitches & onboard expression pedal

Sale Price $319.00
Retail Price $440.50
You save $121.50


 Guaranteed Lowest Price
100% Satisfaction Guarantee
Free Freight on most products
Lifetime Technical Support
Easy Financing
Our Low Price Guarantee

BOSS ME-50B Bass Multiple Effects

The BOSS ME-50B is a bass player’s dream come true. The BOSS ME-50B puts premium bass effects in a sturdy floor unit with simple pedal style control. Effects are separated into six sections—Compressor/Limiter, Master, Filter/Tone, Drive/Synth, Delay/Modulation and Expression Pedal— providing bassists with an array of unique and powerful tones including all-new effects like Sound Hold, Octave Up and Kick Drum. Effects can be customized using 23 knobs and controlled using three integrated footswitches and an assignable expression pedal. Without a doubt, this is the effect pedal no bass player should be without! BOSS knows that bass players want instant access to powerful effects without the hassle of menus and programming. Look no further, the ME-50B is here! You may also be interested in the ME-20B Bass Multi Effects.



BOSS ME-50B Key Features:

  • Floor-based bass multi-effects processor w/ easy analog control
  • Premium COSM Compressor/Limiter & Drive effects, plus T-Wah, Slow Gear & Defretter
  • Innovative Sound Hold feature for maintaining a low note while playing on top
  • Sound On Sound recording w/ new Kick Drum effect for keeping time
  • Designated knobs for each effect section— no complicated menu navigation
  • Easy Tone effects w/ Preset EQ templates for convenient tone editing
  • Three footswitches & onboard expression pedal routed to 6 options like Octave, Wah, etc.
  • Rugged metal chassis built to withstand abuse

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.

BOSS ME-50B Bass Multiple Effects

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)
  • PHONES jack
  • 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.

Call 1-877-477-6432 for any technical questions or if you need SPECIAL PRICING regarding this product