Waves L2 Ultramaximizer: Software goes Hardware

PLEASE NOTE: This article has been archived. It first appeared on ProRec.com in July 2000, contributed by then Editor-in-Chief Rip Rowan. We will not be making any updates to the article. Please visit the home page for our latest content. Thank you!

The Waves L1 Ultramaximizer plug-in has earned respect from virtually everyone who has ever used it. It is a very transparent limiter that doesn’t overshoot, allowing it to be safely used as proof against digital clipping. Now, Waves has released a hardware version of the L1, the L2 Ultramaximizer.

The L2 Ultramaximizer is a stereo digital peak limiter that boasts high-quality 24/96 conversion, digital I/O, and a 48-bit digital signal path. The L2 is housed in an attractive 2-space rack unit. Although it is a purely digital processor, care has been taken to provide it with a user interface that makes it “feel” like a piece of analog gear. I for one will no longer subject myself to dinky 2-line LCD displays and 4-button navigators, and I’m glad the L2 provides a useful user interface.

A Pretty Face. And More

The left side of the unit provides options for input source, sync, and processing. An input selector allows the user to choose from among S/PDIF, AES/EBU and analog inputs. The user may choose to sync to the L2’s wordclock input, S/PDIF input, or its own internal clock. Two buttons allow the user to choose sample rates of 44.1, 48, 88.2, or 96 KHz. A quantize button allows the user to select the output bit depth: 16, 18, 20, 22, or 24 bits. And finally, two buttons are provided to select from among several dither and noise shaping options (more on that later).

A trim control is provided to match the unit’s analog inputs to your analog source. A link button links the right channel to the controls of the left channel so that the unit works in either true stereo or dual mono modes. Bypass and peak reset buttons perform their usual functions.

The other knobs control the unit’s threshold, output ceiling, and release time. If you’re familiar with conventional limiters, the controls will seem a little unusual.

There is no gain knob. Repeat: there is no gain knob. The L2 operates by automatically increasing the gain of the signal so that the level indicated by the Threshold level corresponds to the level indicated on the Output Ceiling. So, for example, if you were to dial in a threshold of –12 and an output ceiling of –1, then the unit would automatically add 11 dB of gain, and limit your peaks at –1 dB. If your source material had peaks at –8 dB, then you would be getting 4 dB of gain reduction on the peaks.

Confusing at first: the bargraph display indicates the left input level.
The knob controls the Threshold level, indicated by the numerical display.
This was counterintuitive at first.

Once you understand that you lower the threshold to increase the gain, everything else makes perfect sense. The bargraph meters offer visual indication of the input level, output level, and gain reduction. The three numerical meters indicate the Threshold, Output Ceiling, and Release Time.

While these controls seem to indicate a relatively complex design (especially for a limiter), in reality, operation is pretty much set-and-forget. For almost all of your applications, you will use one knob (the Threshold control).

Back-panel connections are straightforward. L2 allows balanced +4 connections on ¼” TRS or XLR for its analog I/O, as well as S/PDIF and AES/EBU digital I/O. A BRC wordclock connector is also provided for syncing to other units with wordclock.

Use and Listening

I spent some time with the L2 in my gear rack, trying it on various applications, and have found it to be easy to use and good-sounding.

The A/D input stages and converters are pristine. The L2 offers one of the best-sounding front-ends to any digital system ever offered, certainly on par with any other audiophile converters. Noise is extremely low, and the transparency of the converters is audibly better than “prosumer” 24/96 converters such as those found in the Delta 1010 and Gina 24 which I used as a reference point.

The system is simply a great limiter. I’ve been using the L1 plug-in for over three years now, and I’m spoiled by it. The limiter uses a lookahead technology which buffers the incoming audio so that it can “see” where the waveform is “going”. Then, the audio is attenuated to prevent clipping. This allows instantaneous gain reduction and a tremendous amount of gain reduction before introducing unwanted audio artifacts. In my experience, the only “artifact” produced by overusing the L2 or L1 limiters is simply the bad sound of too much limiting.

The L2 offers an Automatic Release Control, a feature not found on the plug-in version. The ARC shortens the release time for short transients to provide the shortest possible release times. This proprietary function further prevents audible pumping artifacts.

The effect is great. The L2 is, of course, perfect when you need a transparent digital limiter for moderate volume enhancement and peak control. However, what you may not know is that it makes a great stompbox.

One of the first things I do when I get any new gear is to torture it for a while. Heck, some of my coolest moments have been created through the deliberate misuse of some gear or another. In fact, if you aren’t intimately familiar with the various forms of distortion produced by turning all of your gear up all the way then you’re missing out. I’m talking about delays, reverbs, preamps, compressors, EQs, radios, whatever.

Well, the L2 is a fun “effect” when used to overlimit and distort incoming audio. I love using the L2 on bass to just create a big fat chunk of bass, or on vocals to really flatten out the peaks and rough up the sound. And, of course, it’s a great effect on a drum submix or a pair of room mics. There’s nothing more Zepplinesque than an overlimited pair of drum room mics. Suffice to say that the L2 is more than just a pretty mastering limiter.

The fact that the system offers a full 48 bits of internal resolution is interesting. For my applications, which are rock / pop in nature, the additional 24 bits of resolution provided no audible performance improvement versus the 32 bit resolution of my L1 plug-in.

However, I’m willing to believe that for dynamic material, especially classical material which contains a lot of important low-level program content, the 48 bit resolution is more important. After all, if your 24 bit source tape was recorded with 6-12 dB of peak headroom, and you’re tracking an especially quiet passage, you may be dealing with really important sonic material in the lowest 8 to 12 bits. On a passage like that, if you bring up the gain with the L2, every single bit counts.

Dither This

The L2 allows you to output to a number of bit depths from 16 to 24 bits. This capability allows the L2 to operate nicely with a variety of standard (and not-so-standard) digital gear. On the way out, the L2 allows you to choose a number of optional dither and noise shaping options.

If you’re not familiar with dithering and noise shaping, what these options do is to minimize the effect of digitization by adding a tiny amount of controlled noise into the signal. A great visual representation is to use graphic dithering as an example. Which of the circles below looks best to you?

Chances are that you preferred the top circle. Now, what if I told you that the top and bottom circle use the same bit depth (8 bits) but that the top circle had been dithered, while the bottom circle had not. If you look at a blow-up of a section of the circle, you can easily see the added noise:

So, if you consider the top section to be the “source”, then the bottom section is certainly “noisy.” However, which one better represents a circle?

Waves proclaims that their dithering and noise shaping offers 3 bits of additional “virtual” bit depth. I am not in a position to confirm or deny their data, but I can confirm that a properly dithered and noise shaped recording sounds better than an undithered one, particularly at lower bit depths like 16 bits. I have a lot of experience with Waves’ IDR dithering and noise shaping technology, and find it to be on par with the industry standard UV22 technology.


It’s no stretch to say that the L2 is a top performer. It has exceptional conversion, as-transparent-as-possible limiting, an excellent user interface, and simply great sound. No question.

The real question is: is it really worth a list price of $2400, and if so, to whom? After all, $2400 will get you most of the way (if not ALL of the way) to a DAW – complete with L1 plug-in.

Several applications exist where the L2 would find a useful home.

Application 1: ADAT-based studio with analog or digital mix to DAT
1. Gold-channel stereo front end to the ADATs (you’ve never heard such great sound come out of a blackface ADAT)
2. A great limiter to use as an effect
3. A/D conversion from analog mixing desk during mixdown
4. Peak protection and dithering for enhanced 16-bit DAT resolution

Application 2: Analog-based studio with analog mix to DAT
1. A great limiter to use as an effect
2. A/D conversion from analog mixing desk during mixdown
3. Peak protection and dithering for enhanced 16-bit DAT resolution

Application 3: Outboard-gear-based mastering facility
1. D/A conversion for converting digital media to analog
2. A/D conversion from analog outboard gear
3. Peak limiting and dithering for enhanced 16-bit resolution

Any tape-based studio or outboard-based mastering facility will probably benefit from the addition of an L2 into the arsenal. However, for the DAW-based studio or mastering facility, the L2 is probably not worth its hefty price tag.

Waves has broken new ground as a software-only company breaking into the hardware market with a revolutionary new product. I have to applaud Waves for making a single-function unit, rather than a Wonderbox that does reverb, chorus, compression, EQ, dry cleaning, tax preparation, and needlepoint using a two-line display and two tiny buttons to run the show. One can only hope to see a hardware version of Waves’ killer Renaissance Compressor.

As limiters go, the L2 is truly a breakthrough product. I have yet to hear any other limiter, digital or analog, that is as capable of both remarkably transparent operation and zero-overshoot digital safety. While it’s not for everyone, the L2 Ultramaximizer is sure to find a welcome home in many professional production and mastering facilities.