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[Bender Mastering]

Hello everyone,

I've been using the Prism Sound MLA-2 (latest revision) for a couple of months now. I'm still getting used to the unit but overall I'm glad that I bought it.

I do have a question regarding the unit attack times... The MLA-2 is an optical compressor as far as I know of and the unit displays attack times of 0.005, 0.020, 0.100, 0.50, 1.0 and 1.5 ms! The first thing that came to my mind was that the values must be wrong because with these values the MLA-2 would be faster than a UA 1176, and it sure doesn't sound like a fast attacking compressor!!

I've read the manual and then I've noticed that the attack times are measured in milliseconds per dB, not just milliseconds which is how most compressors measure attack and release times.

So how does this milliseconds per dB relate to normal attack times? Is there anyway to estimate how fast this unit really is without measuring it?

Thank you,

[urm eric]

Bender Mastering wrote on Wed, 22 September 2010 14:11

Hello everyone, I've been using the Prism Sound MLA-2 (latest revision) for a couple of months now. I'm still getting used to the unit but overall I'm glad that I bought it. I do have a question regarding the unit attack times... The MLA-2 is an optical compressor as far as I know of and the unit displays attack times of 0.005, 0.020, 0.100, 0.50, 1.0 and 1.5 ms! The first thing that came to my mind was that the values must be wrong because with these values the MLA-2 would be faster than a UA 1176, and it sure doesn't sound like a fast attacking compressor!! I've read the manual and then I've noticed that the attack times are measured in milliseconds per dB, not just milliseconds which is how most compressors measure attack and release times. So how does this milliseconds per dB relate to normal attack times? Is there anyway to estimate how fast this unit really is without measuring it? Thank you,

Quite a coincidence - I wrote about this just a moment ago answering DC on another mastering board (there are others?) and then deleted it as it was confusing (me).

I don't know the answer, but I don't think the Maselec is a slouch: although the Pendulum is probably the fastest opto out there. The Maselec is also, of course, partly programme dependent - those time constants aren't actually constants!

For what it may be worth, when I want generally unobtrusive and something to help with pudgy lows I use the Pendulum, when I want to be a bit more dynamically obvious I use the MLA-2 attacking at 20 and sometimes 100.

Anyway, congratulations on getting the MLA-2 - you will never want to sell it.

Cheers,

Eric

[djwaudio]

We used the MLA-2 with high ratio, fast attacks and release times, for fast punchy sounds when doing punk records.  Loved that thing, why I don't still have one I don't know.

I'm guessing Leif Masses, the designer, can explain the time vs dB concepts to you.

[mcsnare]

I've been using one for the mast coupla months and I really dig it. I've wondered about those time constant markings myself. Very smooth, unobtrusive compression.

Dave

[Gold]

djwaudio wrote on Wed, 22 September 2010 20:21

We used the MLA-2 with high ratio, fast attacks and release times,

I have settled into using this way almost exclusively. I think of it as a 'sloppy
limiter'.

[Bender Mastering]

djwaudio wrote on Thu, 23 September 2010 01:21

We used the MLA-2 with high ratio, fast attacks and release times, for fast punchy sounds when doing punk records.  Loved that thing, why I don't still have one I don't know. I'm guessing Leif Masses, the designer, can explain the time vs dB concepts to you.

I've tried this approach today with success. Along with Paul Frindle's DSM i've managed to have my compression needs filled. Maybe i just need a compressor with more character for rock like the vari-mu or the 2500, but right now i've been fine.

I'll try to contact Leif through is website to see if I find more info on this. If i'll get the answer i'll explain it here.

Regards,

[AndreasN]

Had a look at the pics of the compressor and the legend says "ms/dB" on the attack and "sec/dB" on the release. May explain something?

[Geoff Emerick de Fake]

The venerable dbx165 and the more recent 160SL and 162SL also have dB/ms and dB/s scales. That's tied to the way the side-chain works. In an opto compressor it is possible to force the optocoupler to act quicker than its intrinsic speed by using a combination of feedback and brute force. the result is a system that has its speed limited.
But almost all compressors have that kind of limitation (pun not intended); most manufacturers indicate the attack and release time for a specific amount of GR (generally 8-12dB). If you measure an 1176 for 20dB GR, it is almost twice the time for 10dB.
You do the math:
0.005 x 10 = 0.05 ms =>50us
That's very fast for an opto compressor, so maybe they use a faster variety of sulfur and they have to use electronics to taylor their timings.

[Bonati]

Good thread - I just got a MLA-2. Slowly collecting all of Leif's pieces. Haven't tried using it a limiter yet - new fun for a Friday. Are most of you always keeping the input & output "balanced" in use (i.e. when input gain setting = -10, output = +10)?

[urm eric]

Bonati wrote on Fri, 24 September 2010 09:12

Good thread - I just got a MLA-2. Slowly collecting all of Leif's pieces. Haven't tried using it a limiter yet - new fun for a Friday. Are most of you always keeping the input & output "balanced" in use (i.e. when input gain setting = -10, output = +10)?

Hmm ... I suddenly like the idea of collecting all of Leif's pieces too: such great stuff, such a nice man. I have the MLA-2 and the MEA-2, so that leaves a couple of more pieces to go before we start on the consoles ...

To your question: no, in fact I often use the MLA-2 for adding gain as it's generally the final piece in the analogue chain and it sounds very clean (compared to, for example, the OCL-2 which always seems to my ears to add a touch of stridency with output gain).

Cheers,

Eric

[Bonati]

urm eric wrote on Fri, 24 September 2010 10:51

Hmm ... I suddenly like the idea of collecting all of Leif's pieces too: such great stuff, such a nice man. I have the MLA-2 and the MEA-2, so that leaves a couple of more pieces to go before we start on the consoles ...

Don't get me started on the console. I covet it. Have an MEA-2 on the way - catching up!

Quote:

To your question: no, in fact I often use the MLA-2 for adding gain as it's generally the final piece in the analogue chain and it sounds very clean (compared to, for example, the OCL-2 which always seems to my ears to add a touch of stridency with output gain).

Interesting - this is something I'll be trying. Usually the Pendulum PL-2 limiter is my gain-hike guy. I never add gain with the OCL-2 since the damn channels are too hard to match - you'd have to re-calibrate your output levels all over again before capture (i.e. the other million threads where we've all complained about this). Those pots get set to unity gain and stay that way. I need to start using the sidechain too.

[urm eric]

Quote:

Usually the Pendulum PL-2 limiter is my gain-hike guy.

Only, I assume, until your Maselec-likey direction leads you to swap that for an MPL-2?

Cheers,

Eric

[jdg]

mla2 is great for gain staging with the in/out gain controls.
mine are rarely matched, and i rarely see the meters move, but sometimes the lights blink a bit.

[Bonati]

Are you kidding? I cut lacquers man - we have one! (it's my partner's, PL-2 is mine - a little limiter luxury.) Can't be without that high frequency limiter. An inner demon is always whispering to me about the VMS70 controller.

[The Buzz]

In reality, a attack or release time that does not specify how it was measured is meaningless.  On the Maselec, at least it has a meaning.  In theory, the attack and release times should relate to a dB figure, in the case of the Maselec on fastest attack it will take 0.005 x 20 = 0.1mS to attack 20dB of gain reduction (which is very fast for an opto, the best I can get is 1mS for 20dB gain reduction).

You can roughly measure it by feeding in a 10kHz tone burst (approx 1 sec on, 3 sec off,) set up 10dB of gain reduction with fairly fast release and view the resulting output on you DAW.  You should see how quickly the compressor responds to the burst.  Because the wavelength of the 10kHz signal is 100uS, you can see how many cycles of the burst the compressor takes to "grab" it.

I'd be interested to see the results.

Cheers
Tim.