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Dave Hill Designs RA Plug-In Review


RA emulates amplifier overload, giving control over even harmonics, compression of low-level audio and peak level.

RA is a TDM (only) plug-in from Crane Song’s Dave Hill that allows for the manipulation of the ideal linear-transfer function of a virtual amplifier. Running in Mac (and coming to PC soon) Pro Tools hosts only, RA provides four different sections to precisely add generated even and odd harmonics and other distortion artifacts typically brought on by an amplifier overdriven into nonlinear operation.

Starting from the left side of the GUI, the Drive control’s ±6dB range matches the plug-in to the incoming track’s level. RA’s distortion production and amount are dependent upon incoming level, and Drive sets the plug-in’s aggressiveness. Corresponding to the right side is the Trim control, which sets RA’s output level over a ±6dB range. In general, I found RA requires constant A/B’ing to the original sound because all of the controls interact and affect the final throughput audio level—it is easy to fool yourself. Drive and especially Trim allow you to match levels.

The next section generates second harmonics. The Top Peak knob sets the amount of harmonic generation coming from the loudest, higher-level moments in the audio while, conversely, Bottom Peak controls harmonics coming from lower-level signals.

The Low Level control lifts low-level signals with little effect on higher-level audio. Low Level offers the sound of an overdriven amp when bringing up lower-level portions of the audio, yet all but ignores high-level sounds that, in a conventional amp, become totally distorted and “blown up” sounding. Low Level also produces third-harmonic distortion as you increase it.

The Peak Control section allows low-level signals to pass unaffected and produces third-harmonic content. It acts like a soft clipper but with control over exactly how and when it saturates. The Peak control sets the amount at which the peaks are rounded off and Hardness limits peak levels anywhere from -3 dBfs to -10 dBfs.

Once I wrapped my head conceptually around what RA does, I was ready to try it on everything. When making parameter adjustments, the linear-transfer function line—shown graphically as a straight line of output vs. input on the right side of GUI—contorts and changes shape. Checking this graph when winding up/down on any control is extremely helpful when setting up and refining distortion effects. Somehow, I wish it were bigger, more detailed and calibrated.

For lead vocals, RA is for the distortion connoisseur. Using RA in this way is like playing a sonic sommelier—you can select any or all of the plug-in’s three sections to add just the right blend of grit, grunge or “hair” to a singer’s voice.

For my male rock singer, I found it better to start with the Top and Bottom Peak controls because even harmonics are so pleasing that they can be hard to discern in small amounts; plus, adding odd-ordered harmonics later tends to overpower them.

My singer has a very clean and pure tenor voice with an occasional and wonderful gravelly, hoarse quality at the low-level beginnings and endings of words and phrases. Adding Top Peak brings only those moments out by distorting them more. My ear went to them immediately, but not as if they were now a huge, standout effect. Adding too much of second-harmonic distortion can sound like a loose microphone part ringing sympathetically at the octave above the predominant pitch sung. The Bottom Peak control seems to round out the vocal sound in a “tubey” way that you’d get from a vintage mic pre.

I then used the Low Level control as a kind of low-level expander. This changed the singer’s dynamics, but not like a compressor as the loud bits stayed loud. You can think of Low Level as a “detail” control that enhances only quieter moments. The overall level through the plug increases so, again, I level-matched by clicking the Bypass button and adjusting the Trim control downward.

Adding the Peak Control section blends in more noticeable third-harmonic content. Odd harmonics can get nasty, and there is plenty of adjustment available to get just the right amount of this filth. On my vocal track, third-harmonic distortion shows up during the same vocal moments as the second-harmonic distortion I added. I had the Peak knob at about 2 to 3 p.m. and the Hardness control acted and sounded like a vicious limiter when turned up to 100. You can hear the vocal clamp down on loud peaks that softened up the overall sound and performance.

Superwell-recorded grand pianos get roughed up in a nice way. Setting the Peak control’s knobs both on 100 and Low Level set to about 2 p.m. works like a transparent limiter with a slight softening of loud peaks. For pianos recorded with the treble and bass ends of the harp, and action panned left and right, I would unlink a stereo instance of RA so that I could use different settings appropriate to each side.

Direct basses often are too clean and “yo session player” sounding, but I was looking for something more interesting, especially for standouts and fills. With RA set as Top Peak at 100, Low Level about 3 p.m. and Hardness at 50, it produced a bass sound that remained round and thick, and only slightly distorted when playing higher up the neck—as if the bass amp was about to go up in smoke. Following RA with my usual compressor plug produced a better result than without it.

Dave Hill’s RA is a one-of-a-kind plug-in for distorting sounds in a very precise and controlled way. It’s a sonic personality and vibe-builder in one, and will multiply the effect of any subsequent plug-in after it.

Barry Rudolph is an L.A.-based recording engineer.

Click on the Product Summary box above to view the RA product page.