The BEST bass compressor

[12Bass]

i think you hit the nail on the head 12bass but i think it also comes down to how the side chain is triggered and what frequency range is used there also i always thought that fmr was mainly digital circuits

Yes, that's the sort of stuff McQ was talking about.  As for the FMR line, the compressors employ an analog audio path while the VCA control circuit is part digital.

[StephenGiles]

BTW, some time ago I spent a couple of hours talking with Mark McQuilken from FMR.  Mark helped me swap in a pair of THAT 2181As for a slight improvement in sound.  One of the points that he mentioned during our chat was that the VCA chip is less important to the overall sound than the detection and control circuitry (which serve to determine the "character" of the compression).  So, by itself, choosing a specific VCA is no guarantee of good sounding compression; that's a product of the overall design.   From personal experience I've also found that the quality of the analog circuitry can make a noticeable difference in transparency.

Couldn't agree more, and even more so on auto filter units - for example the EH Q Balls. I've watched those videos on Youtube over and over and I'm sure there is some very clever detection and control sitting in there!

[Projectile]

I did a lot of research a while back and ended up building a Demeter Compulator clone. It's not necessarily "the best" bass compressor out there, but it certainly is one of the best. Unfortunately there aren't a lot of schematics and layouts available for most compressor pedals suited to bass, so if you want to build it yourself, the demeter compulator is one of your only options. Luckily it's a very, very nice compressor.

If you want to hear an ongoing debate on what is the absolute best, then you are better off going over to talkbass.com or another forum that specializes in bass guitar. If you are lookign for DIY, then Demeter Compulator is probably the way to go. (Unless another popular bass compressor has been traced since then, and I somehow missed it)

There has been a lot of talk here about the FMR RNC, and while it's undeniably a fantastic compressor, most of the reviews I've read say it doesn't really shine on bass guitar. It's a very transparent compressor, and usually for bass guitar you'd want a compressor that pumps and breathes a little or it will sound too sterile.

This site is a great resource with comprehensive reviews on a lot of compressors; it focuses specifically on bass guitar:
http://www.ovnilab.com/

[12Bass]

There has been a lot of talk here about the FMR RNC, and while it's undeniably a fantastic compressor, most of the reviews I've read say it doesn't really shine on bass guitar. It's a very transparent compressor, and usually for bass guitar you'd want a compressor that pumps and breathes a little or it will sound too sterile.

One way to put it is that the RNC1773 "gives you enough rope to hang yourself".  Without skilled adjustment, it can sound bad with bass.  Part of the issue is that the RNC is capable of extremely fast attack/release times.  For bass, often slower is better - many of the "classic" compressors are pretty slow acting.  Those pumping/breathing sounds are in there with a bit or tweaking, though it does tend to stay fairly neutral sounding compared with many other compressors.  I'd agree that it it probably not the best choice for those looking for color.

[StephenGiles]

I've also heard that the Ashdown Bass Compressor is very good. I thought I had the circuits for this but probably filed them in a less obvious place on my hard drive.

[Earthscum]

 ...

[DavenPaget]

...

I saw your rant anyway 

[Earthscum]

...

I saw your rant anyway 

lol... yeah, goes along with guitarists that just crank up the distortion and swear up and down that all distortions sound the same without regard to their own playing.

[DavenPaget]

...

I saw your rant anyway 

lol... yeah, goes along with guitarists that just crank up the distortion and swear up and down that all distortions sound the same without regard to their own playing.

Yeah fair enough , to me ( i am a guitarist ... with a difference ) , no 2 distortions sound the same ... unless it's a exact clone 

[electricteeth]

I use a "transmogriphier" or a tube screamer depending on what i am doing. If it is supposed to sound "clean" i use the mogriphier and if it is supposed to sound flat and distorted the screamer does me just fine with mah tube head. Touchy subject though. Alot of the time you can get good bass compression by changing the height of your pickups.

[12Bass]

On the necessity of compression....

No, I don't think that compression is absolutely necessary on bass, though it is extremely rare to find a modern recording without it.  For live playing, I have mixed feelings.  If I use compression at all, I tend to employ a low ratio with a slowish attack and set the threshold to just add a little clamping on transients.  Still, sometimes I feel as if I'm fighting the compressor for control over dynamics and end up bypassing it instead.  For slap and other percussive techniques, compression can be quite useful.

[SteveFromBerlin]

I will build one of those THAT-kits by Musikding within the next two months and let you know how it sounds: http://www.musikding.de/product_info.php/info/p2650_THAT-JAM.html
It is not multi-band but supposed to be very good.

[gritz]

I will build one of those THAT-kits by Musikding within the next two months and let you know how it sounds: http://www.musikding.de/product_info.php/info/p2650_THAT-JAM.html
It is not multi-band but supposed to be very good.

Speaking of THAT compressor applications, hardcore modders may be interested in a paper on the THAT website entitled "Adaptive Attack and Release Rates using THAT RMS Detectors"

http://www.thatcorp.com/Design_Notes.shtml

(it's Design Note 114).

I'm breadboarding it at the moment - I've not hung it off a THAT RMS detector, rather I'm just using the active capacitor part in a standard envelope detector like this:



I've replaced C2 above with THAT's active capacitor circuit.

It's early days, but it does seem to be working like it should. Sorry for the hijack, but as has been mentioned getting a control signal that's free of ripple but still responds quickly to transients is the Holy Grail of single band compressors.

[jonasx26]

I'm breadboarding it at the moment - I've not hung it off a THAT RMS detector, rather I'm just using the active capacitor part in a standard envelope detector like this:

Cool! I've been meaning to try just that but I haven't had the time. Would really appreciate future posts of your findings.

Some time ago I was struggling with designing a vactrol-based compressor/limiter for bass.
Achieving very fast/good responsiveness-to-playing and zero CV-ripple from a single supply sidechain-circuit is quite the challenge.

All the best. / Jonas

[gritz]

I'm breadboarding it at the moment - I've not hung it off a THAT RMS detector, rather I'm just using the active capacitor part in a standard envelope detector like this:

Would really appreciate future posts of your findings.

I'll have to work out how to use all this new-fangled CAD stuff before I can post anything more than scans of pencil diagrams... I'm stuck in 1991 and am struggling to get out!

Some time ago I was struggling with designing a vactrol-based compressor/limiter for bass.
Achieving very fast/good responsiveness-to-playing and zero CV-ripple from a single supply sidechain-circuit is quite the challenge.

I'm wrestling with a vactrol circuit too right now. The vactrol's finite response times mean that I'm getting best results with a CV consisting of full wave rectified audio with a_bit_of_smoothing. If I try a "conventional" envelope follower I get all manner of overshoot and nastiness, so I've been tuning the current through the vactrol and the resistor it forms the divider with to let it's natural response govern the compressor decay time. It's ok, but there's a bit of harmonic distortion. I am chasing a heavy distortion ratio and a fast response time though. I'm a vactrol newbie too - I've only ever done vca based dynamics thingies.

All the best. / Jonas

You too bud!

[jonasx26]

I'll have to work out how to use all this new-fangled CAD stuff before I can post anything more than scans of pencil diagrams... I'm stuck in 1991 and am struggling to get out!

I wasn't expecting schematics, but maybe a brief verdict on the 'non-linear capacitor circuit's usability in a VCA-chip-free sidechain.
If the circuit snippet seems usable I'd most likely tailor it to suit my needs and stocked parts anyhow.
But hey, if you're willing to let me in on your progress that would be great too 
Nothing wrong with scanned pencil diagrams.

If I try a "conventional" envelope follower I get all manner of overshoot and nastiness

Exactly! It seems to me that using a more "elaborate" envelope follower circuit is somewhat pointless if the vactrols characteristics are not taken into account, as these can tend to 'swamp' those of the sidechain. Wow, long sentences for a swede..

I am chasing a heavy distortion ratio and a fast response time though.

As was I when experimenting with my bass limiter/compressor-circuit! I also wanted REAL and truly non-interactive ratio- and threshold-controls.
I suspect the vactrols non-linear resistance vs. current -response is a important factor. Linearizing the vactrols response to CV is key for hard limiting.
This is not a trivial task, at least not for me 

Check out Silonex application notes if you haven't already, some clever solutions there.
http://www.silonex.com/audiohm/compressor.html


I think the reason optical compressors allegedly are considered more "musical"-sounding is due to the non-linearities of the vactrols.
So a 'mathematically' perfect, superlinear optical compressor might just be equal to a VCA-design in terms of "musical quality".. Not sure if I'm making sense here.

This compressor stuff sure is difficult to do right.
Take care! / Jonas

[pedalgrinder]

Hey 12bass i think you got the wrong impression of a good compressor i might add. A good compressor should enhance your tone while stopping your speakers launching into orbit when you drive your bass amp hard. It's not about tone and all that always. Sometimes you need to drive your bass amp hard without kicking the living life out of your speakers and the only way you can do that is with a good compressor. I almost see it as essential for a decent bass player. I know there are guys that don't use them but there not getting the best out there amps. Even a ampeg svt the holy grail a compressor certainly even makes them come to life. People under estimate compressor so much there the most misunderstood piece of audio equipment out there. I strongly suggest finding one with a good release function on it. Makes all the difference i don't understand why so many manufacturers leave it out. Sooooooooooooooo needed.

[12Bass]

The amp that I use for gigs has a limiter in case things get out of hand, but I seldom play loud enough to engage it.  Nor do I push my speakers until they bottom out.  Not sure I agree that bassists really need a compressor in their rig; I think that it depends upon a number of factors, including musical style, technique, as well as the capabilities of the amp and speakers.  Players who have a hard time controlling dynamics might benefit, as would those who tend to push their amps hard and blow speakers.  Compression can also raise the average signal level and run speakers into their thermal limits; so having a compressor in the rig is no guarantee of speaker safety.  So, yes, compression can be very useful for bassists... but is it necessary?  It depends....       

[Johan]

since this is about compression for bass, I wont try to talk you into something else. 
..but, many bassplayers have their pickups very close to the strings and it makes the dynamics extreme and the output hard to keep even, just as when you close-mic a snare drum with a 57'.  it might be worth a try to first just screw down the pickups, away from the strings
guitarsist does this too, but as a rule play with a lot of distortion wich hides the uneven output
J

[pedalgrinder]

you don't have to lose dynamic range if you know how to use a good compressor. Your all assuming that you squish it. i can set my compressor up so i can thump like a muel with my fingers or be as quiet as a mouse but it still gives that roundness and smoothness that a compressor gives a bass player. My opinion is there essential for a bass player.