MXR M87 attack/release times comparison test

[Alvaro Martín Gómez A.]

Hi everybody.

The demos in this thread are inspired by this request:

Originally Posted by the V

There is one more hypothesis...
Official specs are 20÷800 μs, but the compressor doesn't behave ideally and the actual attack time might be longer - albeit just slightly, like 2÷3 ms at maximum.
That would be more realistically discernible by ear.
(EDIT: this is not to discredit the product, but since it claims to emulate a vintage compressor, it might also reproduce its pleasant "imperfections")

While also thanking Andrew for the video example, one more test that I would do - if I only owned the item... - is the following.

Connect the instrument to an Y cable.
One end enters the compressor and then - via a further patch cable - the right channel on the AUX/CD/etc. input of a soundcard; the other end goes straight into the free left channel.

Then record in stereo some playing, mixed styles, tweaking the compressor etc...
Adjust both the recording volume on PC and the compressor output to avoid distortion.
Finally, normalize or otherwise amplify one channel or the other of the captured signal, to get almost visually identical waves.

Since we recorded exactly the same source, it would be finally easy to compare side by side the envelope of the direct and processed signal, and the behavior of the pedal.

So, I recorded several samples of the same riff with different settings for the compressor. The thing is, I don't have a Y cable, so I recorded the same riff six times with a metronome. So, none of the takes are identical, but I tried to do my best to make them sound the most similar possible.

Common settings for all files:

- Ratio: 8:1
- Input: The most powerful notes light the last (from right to left) yellow LED (-15 dB)
- After recording (making sure there was no clipping), all samples were normalized to 96% using Adobe Audition

What I wanted to do first was mixing the uncompressed tone with each of the compressed examples panning them hard L-R, but I felt that hearing each version through just one channel is not comfortable. So, I recorded each version separately and uploaded them to Soundcloud. Here are the files:

1. No compression:
http://soundcloud.com/alvabass/mxr-m87-no-compression

2. Attack and release in the middle. That should be an attack time of 410 microseconds and a release time of 575 milliseconds approximately:
http://soundcloud.com/alvabass/mxr-m87-both-attack-and

3. Both attack and release times at their slowest. 800 microseconds AT and 1100 milliseconds RT:
http://soundcloud.com/alvabass/mxr-m87-slowest-attack-and

4. Both attack and release times at their fastest. 20 microseconds AT and 50 milliseconds RT:
http://soundcloud.com/alvabass/mxr-m87-fastest-attack-and

5. Slowest attack and fastest release. 800 microseconds AT and 50 milliseconds RT:
http://soundcloud.com/alvabass/mxr-m87-slowest-attack-and-1

6. Fastest attack and slowest release. 20 microseconds AT and 1100 milliseconds RT:
http://soundcloud.com/alvabass/mxr-m87-fastest-attack-and-1

And, in case their are useful, here are the screen captures for each sample's wave file (in the same order as above):








Since I'm a learner, I don't want to comment on this. I want to hear whatever the experts (and anybody who wants to express his/her opinion, of course) have to say. I'm willing to record more samples with other playing styles or other compressor settings if necessary. Thank you for your time!

[Alvaro Martín Gómez A.]

My apologies if some of you found a mess with the Soundcloud files. It's the first time I try to post Soundcloud stuff. Everything should be normal now.

[scottfeldstein]

Very interesting. I kind of like door number two. Makes everything round and even to my ears. But I know nothing. I just started looking seriously at compression just a few months ago.

What do the compressor gurus have to say?

[Alvaro Martín Gómez A.]

A couple settings more:

1. The one with which I feel the most affinity at home (I'll try it tomorrow with my band and see if I feel the same in that context): Slowest attack and moderately fast release (800 microseconds AT and around 680 milliseconds RT - release knob between 1 and 2 o'clock)
http://soundcloud.com/alvabass/mxr-m87-slowest-attack-and-2

2. According to this document, this is the closest you can get to Billy Sheehan's compression settings using this pedal: Fastest attack and release (20 microseconds AT and 50 milliseconds RT), but now with a 12:1 ratio
http://soundcloud.com/alvabass/mxr-m87-fastest-attack-and-2

Screen captures (same order again):

[the V]

Thank you for your extensive testing,
very useful (and carefully done!),
I think it's a really solid proof of the versatility of this great pedal, showing how effectively the user can attain to bring out the notes, or the transients, or anything in between.

[jschwalls]

Sheehans settings are closer to .1 ms ATTACK and .1 sec RELEASE

and he pumps his compressor up to 20:1

he varies ratio between 12:1 and 20:1

great clips