The WMD Acoustic Trauma is an analog distortion stompbox built around two preamps, Cool and Hot, that drive a three-band parametric EQ and a noise gate. WMD called it "The Ultimate Analog Distortion Machine," and Premier Guitar described it as "a wide-ranging distortion/overdrive device" in its Tone Games 2010 stompbox roundup1. The pedal is discontinued: WMD's product page states, "This product is discontinued"2.
What it does
WMD describes the design this way: "Two specially voiced preamps give light break up to full stack overdrive to huge sustaining crunch. Those preamps drive" a three-band parametric EQ and a noise gate2. The EQ spans frequencies from about 40 Hz to 15 kHz, and each band is an independent bandpass filter with adjustable center frequency, quality factor, and gain2. Premier Guitar's review likewise describes an EQ "that spans frequencies from 40 Hz to 15 kHz"1. For players comparing distortion designs, it sits apart from simpler distortion pedals and overdrive pedals by pairing the gain stages with full parametric control and gating; WMD's other distortion design, the WMD Geiger Counter, takes a digital bitcrushing approach instead.
Controls
Premier Guitar counted "A total of 17 knobs are arrayed across the face of the black box," with Gain and Level controls for each preamp on the upper left1. The pedal's enclosure is "adorned with red-and-white punkified graphics and control names written in typewriter font"1.
| Control | What it does |
|---|---|
| Cool Preamp Gain and Level | Gain and Level for the Cool preamp1 |
| Hot Preamp Gain and Level | Gain and Level for the Hot preamp1 |
| Preamp Blend | Blends the dry preamp sounds to the output, bypassing the EQ stages; blending may produce out of phase sounds and frequency canceling2 |
| EQ Freq (per band) | Selects the center frequency of the filter2 |
| EQ Q and Gain (per band) | Each band is an independent bandpass filter with adjustable center frequency, quality factor, and gain2 |
| Gate Threshold | Sets the level that the gate will open and the level where it will close2 |
| Noise Reduction | Controls the level of noise reduced by the gate; all the way up will completely silence noise if the gate is closed2 |
| Stomp Switch | Activates the pedal; the large red LED lights when active2 |
The two preamps are voiced differently. WMD says of the Hot preamp: "This preamp is designed to just get louder and add sustain. It is not designed to clean up, just to rock." More gain adds crunch without changing tone2.
Power and connections
Power depends on which version of the pedal you have, and the difference matters2:
- Newer units: compatible with a standard BOSS style 9V center negative supply2
- Older units: shipped with an 18VDC wall supply, center positive, which WMD notes is "NOT the standard BOSS style"2
Older units use an 18VDC center positive supply, the opposite polarity of the standard BOSS style 9V center negative. Plugging the wrong supply into an older unit is a real risk, so know which version you have before connecting power.
The input, output, and power inputs are located on the right side of the unit, and the Acoustic Trauma shipped with a power supply included1.
What reviewers said
Premier Guitar's review, published as part of Tone Games 2010, a feature covering 30 stompboxes, found a caveat in the gain stages1:
"the preamps could be a little hard and grainy sounding, though by dialing the Blend knob for as much Cool Preamp signal"
The reviewer noted the tone cleaned up with the Blend set toward the Cool Preamp and the guitar volume rolled off1. Every WMD product carries a 12-month warranty after purchase2.
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Questions
Is the WMD Acoustic Trauma discontinued?
Yes. WMD's product page states plainly that the Acoustic Trauma is discontinued, so new units are no longer made. The pedal was reviewed by Premier Guitar as part of its Tone Games 2010 stompbox roundup, and used examples are the only route to one today. WMD still supports its products with a 12-month warranty after purchase, and the company's other distortion designs, such as the Geiger Counter, remain part of its range.
What power supply does the WMD Acoustic Trauma use?
It depends on the version. Newer units are compatible with a standard BOSS style 9V center negative supply. Older units shipped with an 18VDC wall supply that is center positive, which is not the standard BOSS style. Older units also shipped with their power supply included. Check which version you have before plugging in, because the two polarities and voltages are not interchangeable.
What is the difference between the Cool and Hot preamps?
The pedal is built around two preamps, each with its own Gain and Level controls. The Hot preamp is designed to get louder and add sustain rather than to clean up, adding crunch without changing tone. The Cool preamp is the cleaner side, and reviewers found that dialing the Blend knob toward the Cool preamp signal, along with rolling back the guitar volume, cleaned up the tone.
Is the WMD Acoustic Trauma true bypass?
Yes. WMD lists the pedal as true bypass, meaning the signal passes through untouched when the effect is off. The stomp switch activates the pedal, and a large red LED lights when it is engaged.
How many knobs does the Acoustic Trauma have?
Seventeen. Premier Guitar counted 17 knobs arrayed across the face of the pedal, covering the two preamps' Gain and Level controls, the Preamp Blend, the three-band parametric EQ, and the noise gate's Threshold and Noise Reduction controls.
What does the Preamp Blend knob do?
The Preamp Blend knob blends the dry preamp sounds to the output, bypassing the EQ stages. WMD notes that blending may produce out of phase sounds and frequency canceling, so it is worth listening carefully as you turn it. Reviewers also found it useful for cleaning up the tone by favoring the Cool preamp.
Sources (2)
- WMD Acoustic Trauma Pedal Review, Premier Guitar, 2010-10-20
- Acoustic Trauma, WMD
