MXR – Bass Compressor REVIEW

MXR have a dedicated line of bass pedals – the Bass Innovations series. The M87 Bass Compressor is one of the latest additions to this special range of pedals. Let’s plug it in and explore… 

Even though I have no problem with searching the guitar effects market for pedals, it is always a pleasure when dedicated pedals for bass players arrive. MXR’s Bass Compressor appealed to me instantly when I first laid eyes on it so we better get started.



mxr-bass-compressor-control-knobsThe MXR Bass Compressor pretty much follows the ‘classic’ compressor control parameters. You get dedicated ATTACK and RELEASE controls, and for the RATIO setting there is a 4-way toggle knob that allows you to select between RATIO settings of 4:1, 8:1, 12:1 and 20:1.

You will find an INPUT knob and an OUTPUT knob. The INPUT knob adjusts the incoming signal, but it also affects how hard you drive the compression circuit. When applying compression the signal will naturally be decreased, so you will almost always find a control that lets you counter adjust for this loss of volume. The OUTPUT knob does this on the M87.

Finally, even though it is not exactly a control feature, there is a 10-LED gain reduction meter that shows you the amount of compression being applied as well as how fast and for how long it compresses your signal.



white headphone with rhythm symbol

The sound clips are divided into 6 rounds. First, I’ll go through each of the 4 RATIO settings with the INPUT driving the compression circuit at 50%, 75% and 100% for each.

Then I will dig into the ATTACK and RELEASE settings.


NOTE! Please use headphones or ‘real’ speakers. You simply can’t judge low-end material on laptop, tablet or phone speakers…!

NOTE! If you are on a mobile device, please turn it to landscape mode to see the knob settings of the pedal for each audio clip.




With a fair amount of controls at hand, versatility ought to be high. It is a very versatile pedal, no doubt about that. But having said that, I found the parameter range for especially the RELEASE time to be very wide. Sometimes a single ‘pop’ would activate and hold on to the note for so long that the following note was clearly ducked – even drowning. Due to the large range the knob is also quite sensitive, so I found myself easily get into that long-release-time territory. However, once I found a nice sweetspot (that worked for me), I had no issues at all. Admittedly, there could easily be lots of situations or other types of playing styles where a very long release time would come in very handy. So at the end of the day, I am actually not indicating that it is too long or would have been better with a narrower range. I am just pointing out that you should probably take some time to get to knob this particular knob that may not at the first glance appear to be the most interesting part of the pedal.

The RATIO range is also quite wide, from subtle to almost-limiting mode. I found myself using the M87 at the 4 or 8 RATIO setting the most.

Ultimately, yes I do find this pedal versatile and used it with success for both gentle smoothening and rather heavy compression for slapping or picking.



MXR pedals have proven to be solid, and I had no issues whatsoever with crackling connectors or when turning knobs. Everything seemed to be in order in the build quality department.

The visual design is very nice indeed. Love the stylish white color and the gain reduction meter with 7 green, 2 yellow and 1 red LEDs offer some good visual feedback on the stage.

The design of the controls and in general is working really well, too. The one element I wished for just a little once in a while was a blend option. I love parallel compression that allows you to really squeeze the tone, but at the same time have the natural attack and the feel of the dry tone present in the overall sound.

If there is but one thing, it would be something that this pedal would share with a whole lot of other pedals. You have to remove 4 screws to replace the battery. Now, if you like me – and probably 90% of all bass players who use effects – have it hooked up to an external power supply anyway, this is hardly an issue at all, though.




Today (2015), a new M87 Bass Compressor retails at around $190, which is in the medium-to-high price range. It is not a boutique pedal and is more expensive than many other mass-produced compressor pedals, but it is also better than a lot of mass-produced pedals… But is it as good as a boutique pedal? It depends on your personal preference, I guess. Value yes, but not a bargain either.



This is a very good pedal and it offers more parameter controls than most compressors, which can be good or bad depending on your need for controlling details and your insight to how compressors work. One thing is certain; I had a lot of fun playing with this pedal!



Sounds very good

Very versatile

Good build quality

Very nice LED meter



Wide release time range may confuse











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