Waves CLA Classic Compressors (Mac/Win) Review

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FIG. 1: Although their GUIs have different skins and are organized differently, the controls and metering options for Waves CLA-2A (shown here) and CLA-3A are exactly the same.

With the release of CLA Classic Compressors, Waves has expanded its line of plug-ins that model vintage hardware processors. The cross-platform bundle includes models of Grammy Award-winning mix engineer Chris Lord-Alge's personal handpicked Teletronix LA-2A, UREI LA-3A and UREI 1176 compressors. Lord-Alge has mixed pop and rock icons Green Day, Daughtry, U2, Dave Matthews Band and Avril Lavigne, to name just a few.

Unlike the original analog units (which were mono), all three plug-ins in the CLA bundle come in mono and stereo versions. Waves offers both TDM (Mac and PC) and native bundles. The native bundle supports RTAS, AudioSuite and VST formats for Mac and Windows, and AU for Mac. I used the AU versions of all three plug-ins in MOTU Digital Performer 6.02, using an eight-core 2.8GHz Mac Pro running Mac OS X 10.5.4.

That's So Classic

CLA-2A models the Teletronix LA-2A leveling amplifier, an electro-optical tube compressor originally produced in the early 1960s (see Fig. 1). The plug-in's twin sibling, the CLA-3A, models the UREI LA-3A audio leveler, a solid-state opto compressor originally produced in 1969. (The LA-3A is essentially a solid-state version of the LA-2A. For more background on the hardware processors that CLA Classic Compressors are modeled on, see the sidebar opposite, “Plug-in Pedigrees.”) Although the GUIs for CLA-2A and CLA-3A have different skins and layouts, the controls and metering options are exactly the same.

True to their hardware counterparts, CLA-2A's and CLA-3A's compression curves are program-dependent — their GUIs provide no attack and release controls. Turning up the Peak Reduction control increases compression depth, for a maximum 40 dB of gain reduction. The Gain control provides makeup gain. A virtual switch toggles between compression and limiting modes (which, like with the LA-2A and LA-3A, sound very similar unless you hit the plug-in hard). You can switch the virtual VU meter for each plug-in to show the gain-reduction amount or the input or output level.

Another rotary control mimics a pot for a pre-emphasis circuit — originally designed for broadcast purposes — that was located on the original hardware processors' rear panels. Turning down this control makes the plug-in increasingly more sensitive to higher frequencies. That might be useful for de-essing a vocal, for example, but you'll want to use the flat setting for most music applications. The two plug-ins also have a virtual three-way switch that selects between models of 50Hz and 60Hz hum and noise or defeats these analog artifacts.

Black and Blue

CLA-76 (see Fig. 2) has two modes, Bluey and Blacky, that respectively emulate the Silverface Bluestripe and Blackface versions of the vintage FET compressor the UREI 1176 peak limiter. When you switch between the two modes, the entire control layout remains the same and all your previously wrought control settings are retained. Only the plug-in's skin (and, of course, its sonic performance) changes.

Four buttons let you select among 4:1, 8:1, 12:1 and 20:1 ratios. An additional All setting duplicates the aggressive compression curve and added distortion produced on a vintage 1176 by pushing all four ratio buttons in simultaneously. The input control drives the compression depth. Controls for adjusting the output level and the attack and release times are also provided. CLA-76 offers the same VU-style metering, metering source points (input, output or gain-reduction levels) and modeling of analog artifacts (50Hz, 60Hz or off) as CLA-2A and CLA-3A. Additionally, you can completely defeat compression to use CLA-76 simply as a subtle tone-shaping plug-in (emulating only the 1176's preamp section).

All of the CLA Classic Compressor plug-ins have the WaveSystem toolbar familiar to Waves users. The toolbar offers facilities for toggling between two setups for comparison purposes, saving and loading user presets in Waves' file formats, initiating as many as 32 levels of undo and redo, and opening the current plug-in's operating manual.

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FIG. 2 : CLA-76 offers two modes of operation that model different revisions of the classic 1176 FET compressor. The GUI for Blacky mode is shown here.

Nice Curves

In use, CLA-2A and CLA-3A transparently compressed a very dynamic male lead vocal. Their compression curves sounded identical (as they should, since they model the response of the T4 opto cell used in both hardware counterparts). Using CLA-2A's Compress mode, the compression curve sounded admirably close to that of my LA-2A hardware unit. Compared to using the CLA-2A, I could get a hair more gain reduction out of my LA-2A before hearing the slightest hint of amplitude modulation, but the difference was very subtle. Waves maintains the difference is because the aging T4 opto cell in my LA-2A has a progressively less aggressive response over time.

In any case, CLA-2A had a slightly more creamy and band-limited (midrangey) sound compared to CLA-3A's, which offered greater depth and detail. The difference was very much like that between the original hardware units. It's amazing how well both plug-ins make vocals sit in a mix, neither popping out or getting lost in dense arrangements. CLA-2A immediately became my favorite compressor plug-in for lead vocals, with CLA-3A coming in a close second.

On an electric guitar track, CLA-2A and CLA-3A each provided transparent compression and beautifully enhanced pick strike (see Web Clip 1). Again, CLA-3A provided the most depth and clarity, CLA-2A the most color.

CLA-76, whether in Bluey or Blacky mode, sounded awesome on room mics for drums (see Web Clip 2). Using the All (all-buttons-in) setting along with slow attack and fast release times produced hyperventilating drum tracks with wonderful pumping and coloration. Generally speaking, Bluey produces more compression and higher output levels compared to Blacky at the same settings, sometimes resulting in a slightly pluckier sound. Although all control settings are retained when switching between Bluey and Blacky modes, the stringently modeled gain staging of the original hardware pieces results in jumps in level when changing modes, making instantaneous A/B comparisons difficult.

CLA-76's Blacky model was my favorite on overhead mics for drums, increasing ambience and urgency. I could add pleasing solid-state-like grunge to ostinato electric guitar tracks by using Bluey with the compression turned off. All the CLA plug-ins sounded too subtle on bass and acoustic guitar for my tastes. However, CLA-76 Bluey gave a little more density and color to bass tracks and lent subtle presence and leveled dynamics to strummed acoustic guitar.

Repeat If Necessary

All of the CLA Classic Compressors plug-ins are very efficient. With DP 6.02's buffer set to 512 samples, instantiating 144 plug-ins (48 each of the CLA-2A, CLA-3A and CLA-76) used only about 45 percent of my eight-core Mac Pro's CPU resources.

I rated the CLA Classic Compressors a 5 for features despite each plug-in's simple control layout. My reasoning was that all of the controls and metering options for the original hardware pieces are available in the respective plug-ins.

The bundle is a little pricey, but this level of quality commands a premium. The Waves CLA Classic Compressors bundle offers the most accurate emulations I've heard to date of the LA-2A, LA-3A and 1176. The plug-ins are easy to use and sound particularly outstanding on vocals, electric guitar and drums. The CLA Classic Compressors bundle delivers.

EM contributing editor Michael Cooper is the owner of Michael Cooper Recording in Sisters, Ore. Visit him atwww.myspace.com/michaelcooperrecording.

Plug-In Pedigrees

To fully appreciate the value of the Waves CLA Classic Compressors, it's helpful to examine the original hardware pieces that these plug-ins were modeled on. What made them so valued?

CLA-2A emulates the tube-based LA-2A opto compressor. The LA-2A owes its lauded compression curve — famous for its pre-eminent transparency — to the T4 electro-optical cell it employs. The T4 comprises an electroluminescent panel and photoelectric cell that has an inherently slow attack time (around 10 ms) and two-stage program-dependent release. The first stage of release lasts about 40 ms to 80 ms. The second stage can last several seconds when compression is heavy or the signal remains over the threshold for a long time. The two-stage release allows engineers to compress tracks very heavily with little or no modulation artifacts such as pumping or thinning.

CLA-3A is modeled on the UREI LA-3A audio leveler, an opto compressor originally produced in 1969, which was basically a solid-state version of the LA-2A. Some other differences existed between the two processors, but most importantly, they both used the venerable T4 opto cell and therefore had virtually identical compression curves. Compared to the LA-2A, the LA-3A has a more extended frequency response (both in the bass and high frequencies) and typically produces more depth. But the LA-2A's creamy, somewhat band-limited sound still remains extremely popular.

The CLA-76 is modeled on the '60s-era 1176 FET compressor. Whereas opto compressors typically offer the slowest minimum attack time, FET compressors (those that use Field Effect Transistors for their gain-control elements) produce the fastest — as quick as 20 microseconds in the 1176. The 1176 is renowned for its ability to smoothly process instruments having sharp transients, such as drums.

The 1176 was revised more than a dozen times before production was discontinued. Waves CLA-76's Bluey and Blacky modes model the Revision B (aka Silverface Bluestripe) and Revision D-LN (aka Blackface) versions of the 1176, respectively. The two versions of the 1176 have slightly different THD and noise specs, gain stages and time constants.

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