MXR M87 Compressor: Which way to turn the (darn) knobs!!! (HELP)

[PCR]

OK, I'm new to the MXR M87. That said, I have spent countless hours reading the manual, and threads on which way to turn the RELEASE and ATTACK knobs.

The manual reads (under DIRECTIONS):
- Rotate the ATTACK knob clockwise to increase reaction time of compression or counterclockwise to decrease it.
- Rotate the RELEASE knob clockwise to increase the time it takes your signal to return to its uncompressed level or counterclockwise to decrease it.

To me, that says turning the ATTACK knob CW would "increase the reaction time" (i.e. from 5ms to 10ms), thus slowing the attack. And the same for the RELEASE knob, where CW would add the number of milliseconds (i.e. from 5ms to 10ms) that the sound is clamped, thus slowing the RELEASE.

However, in the next section in the manual (under COMPRESSION):
To soften the sound of your attack, dial in a FASTER ATTACK time (CW) and reduce the input control (CCW) to light only the -3 to -5 dB LEDs during note attacks. To accentuate the sound of your attack, dial in a slower attack time (CCW) and a FASTER RELEASE time (CW).

That is basically the exact opposite of the previous bullets.

Please help. My brain is turning into complete mush trying to figure out which way to turn the knob!

Here is the link to the MXR manual: Link to the MXR M87 manual

Thanks,

PCR

Just to be clear:
CW = Clockwise (or turning to the right)
CCW = Counter Clockwise (or turning to the left)
Increasing time would add time; meaning things take longer to start or complete. In other words, a 10 minute task takes longer than a 5 minute task.

 

[tris66]

Wow. Frustrating. I have not played with one of those. It looks like a nice box. All of the comp boxes I've used are fast to the left ccw and slow to the right cw. A lot of people will tell you to set it where it sounds good. That never helped me until I could hear what the compressor was doing. Even big time engineers admit that learning to hear compression takes a long time. I don't have anything for you other than this review that describes how it works:

MXR M87 Compressor Review

If you are looking for minimal coloration or nearly transparent compressor with a fairly wide range of control and great metering, the MXR M87 might be just what you are looking for.It isn't a compressor to make your tone "fat" or to bring on the "tone magic" associated with the likes of other...

www.compressorpedalreviews.com

 

[Chris Chong]

the attack release speed are based o the UA1176 range.

My go to setting for 1176 style comp is attack 10 o’clock (slow), release 4 o’clock (fastest), adjust input to get 3-5 reduction (LED) with 4:1 ratio.

 

[FullumMusic]

I see the conflict you see. You're not crazy. I'd interpret "increase the reaction time" to mean slower reaction time, or, 5ms to 10ms.

One of the best ways to hear what a particular parameter is doing on a compressor is to use EXTREME settings for all the other parameters.
- Keep the Attack at noon
- Put the Ratio up to 20
- Put the Release full clockwise
- Turn the Input up so that you're pretty much SLAMMING the Gain Reduction

Then go Full-CW and Full-CCW on the Attack and see if you can hear which takes longer. Usually it's obvious, but the manual says the Attack range is 20 µs to 800 µs for this compressor, which might be really tricky to hear because it's so short. Even if it's audibly difficult to hear the Attack clamp down at different speeds, you might be able to see the LEDs go to full GR faster or slower.

 

[Thumpin6string]

I went through a similar situation trying to figure out my Markbass Compressore. I finally gave up and instead found a thread on favorite settings for the Compressore. I wrote down all the different settings from all the TBers and started trying them until I found one that worked for me. Now it is always on. Maybe there is a thread on M87 settings. Might be worth a search.

 

[soulstew]

The word “attack” is being used to refer to two different things here. Attack in terms of tone or sound is the initial (louder and sharper) sound that happens when the string is plucked or struck. To preserve that, you would slow the “attack” of the compressor so that it doesn’t catch and compress that initial (louder and sharper) “attack” portion of the note.

Increasing the attack time = slowing the attack time = increasing (actually only preserving, but perceived as an increase compared to a more compressed version) the “attack” portion of the note envelope. It’s unfortunate that “attack” is used for both of those phenomena, but I can’t think of a better way to explain it.

 

[Dbassmon]

Input control determines how much signal is allowed into the detector. There is a threshold voltage that triggers the compressor. Adjusting the input will determine if you are compressing everything or just the loudest signal, depending on how hard you are hitting the input. The LEDs show you when you trigger the compressor.

Attack time is fastest at 0, 20us is fast, and this will clip the transient, and if you slap or have staccato finger style, the compressor will suppress the attack. As you rotate clock-wise, it slows the detection time, allowing more time before the compression grabs the signal.

Release time is also fastest at 0, That is how long it takes the compressor to release after it is triggered. You most likely want to increase the release time so it doesn't choke your next note, but long enough to hear the benefit of the compression.

Output allows you to balance the level after compression. The compressor is lowering the volume, and the output allows you to compensate so your compressed signal is the same volume as your uncompressed signal. That is helpful if you are using compression in some places and not others.

There is a lot of nuance controlled by these parameters and will allows you the freedom to alter your signal in many different ways. You must spend some time with the unit and experiment. This is a pretty sophisticated processor. It is also fairly neutral in its coloration. 1176, for example, adds a lot of coloration, not so with M87.

 

[pbass2]

There's other looong threads about this unit on TB and yes the way the manual describes things is confusing.

On the M87, Attack and Release both go from Slow to Fast, CCW to CW.

For a slower Attack (more of the initial note transient getting through uncompressed because the compressor is reacting more slowly) turn Attack CCW.
For a faster Release (compressor returning to no gain reduction/compression more quickly) rotate Release CW.

The metering is one of its best features. Try this to visualize what the Release knob is doing: get your Input set so that the meter is lighting up a decent amount of lights. Then pluck a staccato note or even just tap on the strings, and compare all the way Slow (fully CCW) to all the way Fast (fully CW). Watch how fast the meter shows the comp "releasing" the signal - the lights turning off - returning to an uncompressed state.

Attack is more subtle and you can't really "see it" on the meter so much, but you can hear it doing it's thing the same way: fully CCW vs fully CW and listening to how your "Attack" is affected. You could also record it into a DAW and look at the waveform and see how the initial transient of the note is affected.

It's a great pedal IMO, and gives a lot of control. The Input knob is super sensitive as you'll discover, that's the most finicky part of it.
I go for a "natural" sound with mine--just a smidge of comp. My settings are Ratio: 4:1, Release 1:00, Attack 11:00. Then Input set so I'm lighting up about 3-4 green lights on the meter with normal playing intensity fingerstyle or pick. Output set to unity gain. This gives me what I'd consider a "transparent" natural sound, I can still play with plenty of dynamics, and it just smooths things out a wee bit. Honestly I can (and often do) play without it, but it's nice to have it on especially with my five strings, and in situations where FOH "isn't all that", or small gigs where just my amp is carrying the room.

 

[JamesGrant]

It’s not helped by some vintage audio gear having attack settings the ‘wrong’ way round (ie; max = smallest time (the ‘most’ attack), min = longest time (the ‘least’ attack). Many reproductions and units ‘inspired by’ continue this tradition.

 

[BassicJazzy]

You are misinterpreting things. Increasing reaction time means the effect comes on more quickly. Decreasing reaction time allows you to hear your basses natural attack longer before the effect kicks in. Increasing release means the effect will last longer. If you want to sustain notes longer, you want longer release time. If you just want to squash the note and then let it go, shorter release time is used. Ratio knob controls the extent to which your signal is compressed. Choose 4 or 8 for a lower compression effect, which is normally where you would set this for routine playing on bass. You dial the input knob to control the strength of the signal fed into the compressor, and to achieve efficient utilization of the effect. Depending on how "hot" your basses output is, you may need less or more input to get the lights into the desired range, but out of the red zone. Consider that sort of like the Gain knob on your preamp.

 

[pbass2]

The manual IS very confusing for sure when it says "Rotate the RELEASE knob clockwise to increase the time it takes your signal to return to its uncompressed level or counterclockwise to decrease it." They are conflating "increase" with "speed up" or "make faster". Most people don't think that way - one would typically assume "increase" means "make more" or "make longer". It's very poorly worded.

Again as I say above, on the M87, Attack and Release both go from Slow to Fast, CCW to CW. The little meter test with the Release knob I describe clears it right up as you can see it in action!

 

[eriky4003]

Make sure you set your input and output knobs correctly first. Plug in your bass and set the input so a few of the meter lights are lighting up when you play at your normal attack (fingers or pick). Then set your output so the volume is the same when you turn the compressor on or off to set it at parity. Then, I'd say, is the right time to read all of the above. For reference, my passive basses has input at 3:00 (o'clock), output at 9:00 and active basses are closer to 1:00 input and 11:00 output.

 

[crguti]

Do you hear a difference when turning the knobs?

 

[BassicJazzy]

Do you hear a difference when turning the knobs?

Oh, yeah! Especially with Release. You can make it sustain indefinitely. It's a little harder to hear the differences between the ratio settings. Depends on your bass.

For people who don't want to mess with all this, the Keeley compressor offers a much simpler set-up. You have one switch to choose either hum bucker or single coil p'ups. That controls your attack and compression setting. Then there's one knob to control the intensity of the effect, i.e. the compression ratio and sustain. I may be slightly off on this, doing it from memory. I traded up from the Kelley to the MXR, due to improved control of the effect.

 

[BassicJazzy]

Make sure you set your input and output knobs correctly first. Plug in your bass and set the input so a few of the meter lights are lighting up when you play at your normal attack (fingers or pick). Then set your output so the volume is the same when you turn the compressor on or off to set it at parity. Then, I'd say, is the right time to read all of the above. For reference, my passive basses has input at 3:00 (o'clock), output at 9:00 and active basses are closer to 1:00 input and 11:00 output.

You are pretty much right on in terms of input. For me output setting depends on what else I have on in the chain. Takes a little fiddling to balance them all out to achieve parity across the board.

 

[pbass2]

Oh, yeah! Especially with Release. You can make it sustain indefinitely. It's a little harder to hear the differences between the ratio settings. Depends on your bass.

For people who don't want to mess with all this, the Keeley compressor offers a much simpler set-up. You have one switch to choose either hum bucker or single coil p'ups. That controls your attack and compression setting. Then there's one knob to control the intensity of the effect, i.e. the compression ratio and sustain. I may be slightly off on this, doing it from memory. I traded up from the Kelley to the MXR, due to improved control of the effect.

Yep, I went with the M87 for a stomp comp because it was setup similarly to an 1176 which is my preferred comp in the studio - I absolutely want control over Attack and Release. That said, I love a good 'ol LA2A on bass too....... And a compressor with "fixed" Attack and Release is still typically program-dependent, but I just like to able to adjust it manually as a rule.
Does the Keeley really have a knob for humbucker vs single coil? As far as how a compressor works, that's plain silly. Now, if it's doing some kinda tone shaping/EQ when you flip that thang, then I get it (if you want that happening with your compressor).

 

[BassicJazzy]

Yep, I went with the M87 for a stomp comp because it was setup similarly to an 1176 which is my preferred comp in the studio - I absolutely want control over Attack and Release. That said, I love a good 'ol LA2A on bass too....... And a compressor with "fixed" Attack and Release is still typically program-dependent, but I just like to able to adjust it manually as a rule.
Does the Keeley really have a knob for humbucker vs single coil? As far as how a compressor works, that's plain silly. Now, if it's doing some kinda tone shaping/EQ when you flip that thang, then I get it (if you want that happening with your compressor).

Yes, it's a switch on the face with those two options. At the time I owned it I didn't have a bass with hum buckers, so I never tried that setting. My impression was it was a decent compressor but not nearly as powerful in terms of the shaping it could do as the MXR, or any of the other higher end compressors. What it offered was a "set it and forget it" simplicity. It did greatly improve the sound from my single coil basses, during the short time I used it.

 

[pbass2]

Yes, it's a switch on the face with those two options. At the time I owned it I didn't have a bass with hum buckers, so I never tried that setting. My impression was it was a decent compressor but not nearly as powerful in terms of the shaping it could do as the MXR, or any of the other higher end compressors. What it offered was a "set it and forget it" simplicity. It did greatly improve the sound from my single coil basses, during the short time I used it.

Ah, I see how they describe it:
"Now there is a simple Release Switch that is tuned for single coils or humbuckers. No more wondering if you have the attack or release set right. Your humbuckers will have all the attack and punch that they should."
That descriptor suggests that it's simply a slower attack time in the "humbucker" setting. Good way to further confuse noobs as to how a compressor works.
But ultimately, as with any gear, if it sounds good to you, then it is good.

Keeley Compressor Plus - Keeley Electronics Guitar Effects Pedals

The Keeley Compressor Plus offers the same gorgeous push of frequencies and sweetening of tone with the flexibility to handle any instrument.

robertkeeley.com

 

[PCR]

RESOLVED!!!!

Back story:
I recently purchased two MXR M87 to replace my two Keeley Bassist. I really like using the 1176 studio compressor, and wanted the same playing live. But when I got the compressors, what I was hearing wasn't matching how the manual says it's supposed to work. (did I have TWO bad units?). It drove me nuts! So I took to the internet and studied the manual. It seemed nobody had the definitive answer.

So I started this thread, and I also entered a message on jimdunlop.com under Gear Support.

I received a reply the next day, and have gone back and forth with their techs. (They were extremely helpful and gracious through the whole process).

So I basically asked them... definitively, "What is supposed to happen if you turn the ATTACK and RELEASE knob clockwise: (CW).

I will copy the summary message below, but essentially: The manual is wrong!!!
It's not like this is a new pedal, this pedal has been around for 15 years (2011)

The conclusion:
ATTACK (CW) = Faster compression reaction
RELEASE (CW) = Faster compression release

Here is a link to the manual in case you want to follow along

Here is the message from the Tech:

Hello Pete,​

Sorry for any confusion. We are aware the manual has some issues, and it is in the process of being fixed. I’m not sure how it will be officially worded but for clarification of the controls it should be something like this.​

Bullet portion:​

• Rotate the ATTACK knob clockwise to increase the compression reaction speed or counterclockwise to decrease it.
• Rotate the RELEASE knob clockwise for a faster compression release or counterclockwise for a slower compression release.

Description portion:​

To soften the sound of your pick attack, dial in a faster attack (CW) and reduce the input control (CCW) to light only the -3 to -5 dB LEDs during pick attacks. To accentuate the sound of your pick attack, dial in a slower attack (CCW) and a faster release (CW).​

​

Best regards,​

Jon​

Kudos to the Dunlop support team to care enough to get back to me quickly.

Good luck,

PCR

 

[JamesGrant]

RESOLVED!!!!

Back story:
I recently purchased two MXR M87 to replace my two Keeley Bassist. I really like using the 1176 studio compressor, and wanted the same playing live. But when I got the compressors, what I was hearing wasn't matching how the manual says it's supposed to work. (did I have TWO bad units?). It drove me nuts! So I took to the internet and studied the manual. It seemed nobody had the definitive answer.

So I started this thread, and I also entered a message on jimdunlop.com under Gear Support.

I received a reply the next day, and have gone back and forth with their techs. (They were extremely helpful and gracious through the whole process).

So I basically asked them... definitively, "What is supposed to happen if you turn the ATTACK and RELEASE knob clockwise: (CW).

I will copy the summary message below, but essentially: The manual is wrong!!!
It's not like this is a new pedal, this pedal has been around for 15 years (2011)

The conclusion:
ATTACK (CW) = Faster compression reaction
RELEASE (CW) = Faster compression release

Here is a link to the manual in case you want to follow along

Here is the message from the Tech:

Hello Pete,​

Sorry for any confusion. We are aware the manual has some issues, and it is in the process of being fixed. I’m not sure how it will be officially worded but for clarification of the controls it should be something like this.​

Bullet portion:​

• Rotate the ATTACK knob clockwise to increase the compression reaction speed or counterclockwise to decrease it.
• Rotate the RELEASE knob clockwise for a faster compression release or counterclockwise for a slower compression release.

Description portion:​

To soften the sound of your pick attack, dial in a faster attack (CW) and reduce the input control (CCW) to light only the -3 to -5 dB LEDs during pick attacks. To accentuate the sound of your pick attack, dial in a slower attack (CCW) and a faster release (CW).​

​

Best regards,​

Jon​

Kudos to the Dunlop support team to care enough to get back to me quickly.

Good luck,

PCR

Good that you got such a comprehensive response - and jolly decent of you to share!

‘increase the compression reaction speed’…

Trouble with the word ‘increase’ is that it means ‘make bigger’. Speed is a measure of distance/time and there’s no distance component so the brain has to work out the intended meaning.

‘Faster’ and ‘slower’ are good words.

‘faster attack - the compressor reacts more quickly when the signal amplitude exceeds threshold.’

‘slower attack - the compressor reacts more slowly when the signal amplitude exceeds threshold.’

Wordz iz hard