Requsite Audio Engineering

818.437.0779Email Danny "Sage" McKinney

L2M Mastering Limiter MK III

- Starting at $5,500 -

L2M Mastering Limiter

  • In it's 12th year of production, the L2M is an optical limiter based on classic designs of the early 1960s and is the beneficiary of many significant improvements, representing what a truly refined optical limiter can be. We classify the L2M as a mastering limiter because it was designed with the specialized requirements of the mastering engineer in mind, though, the L2M is equally at home in tracking and mixing applications.

  • Among the more notable performance features of the L2M are it's sonic excellence, versatility and stable frequency response while limiting program material. When providing unobtrusive compression/limiting action, there is no undulating bottom or loss of openness, even in the heaviest of limiting situations. Corrective EQ, following the L2M, is simply not required. With the L2M, your work stays intact, just as you need it to.

Technical Details


  • In/Bypass
  • Output Level - 1dB, 24-Step Attenuator
  • Limiter Feedback - 1dB, 11-stpe Attenuator
  • Ratio 10:1/3:1 - Limiting/Compression
  • Limiter Response - Continously Variable
  • Peak Reduction - Continously Variable
  • Mid
  • Side
  • Stereo Level Ride
  • Link - Left/Right
  • Meter Select - Gain Reduction, +4dB, +10dB
  • Zero Adj - Gain Reduction Meter Zero Adjust
  • GR Track - Gain Reduction Tracking Calibration
  • Link - Left/Right
  • Link - Left/Right
  • Meter Select - Gain Reduction, +4dB, +10dB
  • VU Adj - Calibration for Volume Units Meter in dB
  • Stereo Adjust - For Balancing Left/Right Peak Reduction
  • VU Meters


  • Ground Connector - Chassis and/or Circuit Ground
  • Power Supply Inlet (choice of Tube or Solid-State Supply)
  • Transformer Balanced XLR Output (pin 2 HI)
  • Limiter Link - 1/4" Jack for linking additional PAL Limiter (not included)
  • Tube Channel - Protective Structure for easy Tube replacement and Ventilation
  • Transformer Balanced XLR Inputs (pin 2 HI)


  • Solid-Core Copper/Silver Wire with Teflon Dielectric
  • Handwired, Point-To-Point Throughout (only Meter/Phantom on PCB)
  • Custom Input and Output Transformers
  • Overbuilt - using highly rated, quality components

Rave Reviews

I received the L2M MKII and power supply yesterday. It arrived in perfect condition with no shipping issues.

I had a chance to use it for about an hour last night. It sounds wonderful! I really love what it’s doing as a 3:1 compressor on the final mix of mycover of Yes’s Long Distance Runaround. The song has heavy, abrupt bass guitar parts with a lot of zing. The L2M MKII rounds it out just enough to sound classy and smooth without losing any of the excitement in the bass performance (the bass has a very resolute, “chin-up” sound). While that’s going on, the vocals, keyboard and guitar are sitting very nicely.

Well, this is a definite improvement on the Manley Vari-mu. Also, the Drawmer 1968 is really great, but harder/punchier on the mix. I much prefer the L2M MKII in this case. I think I hear the “Macintosh” flavor you were after.

A very enjoyable experience. I couldn’t be happier. Thanks, Danny.

Dave Wills

"The L2M is our 'go-to' tone-machine. We love the sense of depth that is lends to the midrange as well as the overall solidity of the bottom and velvety highs. It is a must listen in my book. We also love the +10dB gain switch that enables us to take the direct output of our ATR-102 tape machine (bypassing the output pre-amplifiers) and plugging directly into the L2M. Nothing beats it, ever."

Brent Lambert - The Kitchen Mastering

Concerning the L2M, I have a feeling we will grow old together. I don´t want to sound like an add, but it just sounds terrific! How it is able to do 7-8 dB gainreduction on peaks without any audible side-effects is a mystery to me. The response control is in constant use. On a general level I really find it easy to make a perfect balance between vocal and bass material which is sometimes a huge problem with other units. I do sometimes mix electronic based music with high energy low end and now I find it very fast to set up the L2M for great results. It sounds equally great on acoustic music.

I was really surprised when I unpacked the power-supply. I actually thought it was the limiter. The sheer size of the thing is really impressive.

Basically, it makes my work more enjoyable and and my clients seem very happy.

Best wishes
Helge Sten
Audio Virus LAB
Oslo, Norway

With a seemingly infinite choice of dynamic processors at my disposal I use the Requisite L2M more than all others combined. We own two units and are anxiously awaiting our third.

Andrew Mendelson
Chief Mastering Engineer
Georgetown Masters
Nashville, TN

Dear Danny,

I have long been intending to write a few words about the L2M Mastering Limiter. After singing its praises, again, to someone connected with the world of professional recording it seemed appropriate to put some of my gushing into print. Besides, I promised Danny I would do this months ago.

And, gushing is the right word. You know, in this hyped-up world of ours sometimes it is difficult to discern the spin from the reality. In the case of the Requisite L2M Mark II it is easy. The L2M is the real thing. Period. Any hyperbolic praises you hear from users is well founded in fact and experience. The L2M is a wow.

The L2M is the most transparent instrument of its kind I have ever heard. I choose the words "instrument" and "transparent" carefully. Yes, the L2M is an instrument, built to a standard that others can only dream. External power supply with separate umbilical electric cords to bring B+ and filament voltages to the main chassis. Getting the power supply away from the active audio circuits is the best way. Internal point to point wiring, the kind that tube circuits love best. Yes, tubes don't especially like traces on circuit boards to perform their audio best. Attention to internal wire diameter based on empirical testing and listening experience, and this same attention applied to all active and passive components in the circuit. This kind of attention to detail and passion for achieving the highest performance possible is rare indeed. It is abundantly evident in the L2M Mark II. Doug Fearn engages in this kind of electronic empirical absolutism too, but besides himself and Danny there are precious few others. Sad but true.

I liken the creation of an audio component to the creation of a world class piano. Skill and technique are involved. The heart of the builder/designer is also involved. There are lots of roads taken that prove to be dead ends. Design synthesizes the fruits of the these excursions and builds on the good ones. A high standard is maintained and refined. Hard won knowledge is forged into the design. The bull shit is separated from the truth. And the final test is in the listening. Is the piano you just built going to meet the standard of excellence required? How can you know? Play it and listen. The same can be said of the L2M Mark II. As soon as you listen to it you will understand what you have been missing: clarity, the breath of life, immediacy, non-mechanical, captivating, real, non-fatiguing, transparent, and so forth in this mastering optical limiter/leveling amplifier instrument.

If you are seriously considering a device of this type it would behoove you to put the L2M at the top of your list. But, don't take my word for it. Find, locate, borrow, or rent one and listen to it! Hear how it does what it supposed to and does not damage the sound. Listen to the subtleties, the nuance and gentle audio clues in sound, it allows to pass unscathed and settle on the recorded track. Feel the pathways of auditory processing in the brain open up where once they were on high alert to filter minute micro transients from piquing auditory cognitive sensibilities. Marvel at the open, clear, free feeling the L2M inspires. Breathe deeply and sigh. How wonderfully and utterly sound satisfying.

When you get to this stage of refinement, the L2M Mark II, it is difficult to imagine how it could be made better. I have no doubt that Danny will find a way, if a way exists. In the mean time, go with the L2M. You will be very very happy you did.

Robert Rosenow RFR Audio Lab and Studio

Recording highest quality audio and building boutique single ended triode amplifiers in the heart of Ozark Mountain Country. (but not at the same time)

"I've been doing what I do for about 28 years now and I can use whatever equipment I want, I use Requisite Limiters everyday.

If the throughput of a device doesn't meet my standards of sonic integrity, then I don't use it. The L2M makes me very happy."

Denny Purcell
Georgetown Masters
Nashville, TN

"The Requisite L2M operates much like my old favorite limiter, the LA-2A, only much improved. It is a stereo unit with state-of-the-art tube circuitry, and it retains that warm tube sound. But it's much cleaner and has a very low noise floor.

The L2M includes a great innovation - an expander, or "un-compressor" that is perfect for adding new life to material that has been overly compressed. The compression and expansion are both very handy features to have available for the remastering work that I do.

I never leave home without my L2M!"

Bob Norberg
Senior Mastering Engineer
Capitol Records, Hollywood, CA

Last night I did a session with another engineer from Sear Sound, and oh my goodness, did he ever flip over the Requisite gear. We did guitars, vocals through the Y7s, and ran the L2M compressor on the 2 bus. The Y7s pre is just gorgeous, like a Neve on steroids when you need it, and totally clear and natural like a Grace. I just love the feedback control as well, it's like having a tone control, but unlike any other I've heard.

And the L2M compressor is just stunning. It's interesting how it's set up as a tracking compressor without a lot of knobs and all, but sounds fantastic on the 2 bus too. Very seamless, and clear, and adds just the slightest hint of warmth and color. We were very impressed. I just hope you can really get these out there in the world, they should be in everyone's rack. I really think you have made some classics here, that will stand up for years."

R.L. - Recording Artist - New York, NY

Dan baby;

Paul Orofino here to tell you how happy I am with the L2M limiter... As I write this, one of my clients is mixing a record through the unit, and the results are fabulous!!! I can't tell you how amazing this unit sounds coupled to my VTC console. (a dream come true) The only problem I see is now I have to save up enough to by one for my second room! My engineers won't let me keep this one in the "A" room! Ahh...such problems...

Well as soon as I finish the tracking I will be mixing the new Blue Oyster Cult album through this baby, and quite frankly I can't wait...when was the last time I got so excited by a piece of outboard gear?

Paul Orofino-Millbrook Sound-Millbrook, New York

You know how there are certain things that come in to your life and once they do you realize that you just can't live without them? That was the experience I had when I first heard the L2M Mastering Limiter/Expander from Requisite Audio Engineering. It seemed as if anything I ran through the unit just sounded better. 9 times out of 10 it did.

Imagine using a compressor that sounds like you think a compressor should sound like. No dulling of the sounds, limiting without sacrifice to the program content, fullness without mud.

Build quality, impeccable service, proven design and it looks great too. How could you ask for anything more? Audition one as soon as possible. Just be ready for that "cant live without it experience"

Larry DeVivo - Silvertone Mastering, Inc.

"The L2M sounds full and smooth in a multitude of situations , from individual tracks to sub-groups to the mix buss. Thank you and keep up the outstanding work!"

Gregory Miner - Chicago, IL

The Requisite L2M Tube Mastering Limiter/Expander compressor is simply the best unit that we have ever tried for compressing stereo mixes. There's no pumping, little loss of top end and the compression can be rolled off the bottom end, allowing a more dynamic kick and bass, when appropriate.

It's pretty much replaced the Manley Variable Mu as the last analog compressor in our mastering chain. Thanks to your suggestion of using the Manley before the Requisite (as a peak limiter), I'm getting the best of both worlds. Our recording/mixing engineer has found many useful way to use the L2M for his work and categorized the unit in the "indispensable" category.

Andy Krehm

CD Mastering, Digital Recording Studio, CD and Cassette Manufacturing
Toronto, Canada

"Having a recording studio equipped with compressors such as UREI 1176, Neve, Tube Tech, API, and Federal we have found that the Requisite mastering compressor is the first compressor we use. As a mastering compressor, the Requisite L2M is one of the finest compressors we have heard. When applied to a final mix, we find the L2M blends the individually recorded tracks without losing the imaging, performance, emotion and dynamics of the performance. We can't say enough about it. The Requisite L2M stereo mastering compressor is a must have stereo compressor for any studio."

Joe Ferrainola / Jimmy Moore - Glen Mills Studio - PA

"My Requisite L2 is gorgeous! And the sound is even better. I love it."

Robert Rosenow - RFR Audio Laboratory - Springfield, MO

Special Features

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