The Trace Elliot SMX is a dual-band compressor pedal, a design that was very rare when it was produced. Instead of compressing the whole signal at once, it splits the signal at a crossover and compresses the low and high bands separately, which is why it has a cult following among bassists. It is long out of production, so it now lives on the used market1.
How the dual-band design works
The crossover is centered at 350 Hz, with a shallow slope so the upper and lower bands actually overlap between 225 Hz and 900 Hz. The maximum ratio is 8:1, so even at the highest settings the pedal does not act as a limiter on the strongest peaks. At high ratios there can be a noticeable "pop" or "tic" artifact when the threshold is crossed1.
The compression attack is not adjustable: the pedal presets a fast attack for the high band and a slow attack for the low band1.
The controls and footswitches
- Separate knobs set the amount of compression for the high and low sides of the crossover1
- A "tilting" EQ knob emphasizes either the highs or the lows1
- A second footswitch bypasses only the high band of the compression, meaning only the lows get compressed1
There is no LED or other meter to indicate signal over the threshold, so you set the compression by ear1.
Power: 18V DC and a 2.5 mm plug
The SMX runs on 18V DC, which means either using two batteries or finding an 18V adapter with a barrel plug that has a 2.5 mm center pin. The "normal" 2.1 mm Boss-type plug does not fit1.
Finding an appropriate AC adapter is critical. If one of these pedals is sold with its adapter, it is worth paying more for. For isolated supplies like the Pedal Power II Plus, Voodoo Labs can custom-make a series Y cable for 18V with the appropriate 2.5 mm plug1.
What reviewers said
Ovni Lab's reviewer, Cyrus Joaquin Heiduska, found the noise level fairly low, not the quietest but acceptable, and noted that the pedal rolls off a bit of both the lows and highs. On tone1:
"The overall tone and action are quite smooth and musical, clean and punchy, at most comp settings; only at the highest settings it can sound a bit 'artificial'1."
He judged the pedal not quite up to the same audio standards and capabilities as the Rane or FEA dual-band comps, but found it does sound quite good, and the differences would be less apparent playing live on stage. His verdict: "the Trace SMX is a worthy contender if those qualities are important to you, and if you find one at a fair price," referring to finger-articulation sound and less "swallowing of the highs"1.
The construction is very heavy-duty, a bit over twice the width of a Boss pedal1.
A modern successor
The SMX is no longer in production, so players looking for one today will be searching the used market. The reviewer's overall judgement was that "the Trace SMX is a worthy contender if those qualities are important to you, and if you find one at a fair price"1. For more on how compressors like this work, see Compressor Pedals and Bass Pedals.
Videos
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Nick SL
Questions
What is the crossover frequency of the Trace Elliot SMX?
The crossover that splits the signal into its two compression bands is centered at 350 Hz. Its slope is shallow, so the upper and lower bands actually overlap between 225 Hz and 900 Hz rather than dividing the signal at a single hard point.
Can I use a standard Boss-style adapter with the SMX?
No. The SMX runs on 18V DC through a barrel plug with a 2.5 mm center pin, and the common 2.1 mm Boss-type plug does not fit. You need either two batteries or an 18V adapter with the correct 2.5 mm plug, so a used pedal sold with its adapter is worth paying more for.
Is the Trace Elliot SMX true bypass?
No. The footswitches are not true bypass, though the reviewer at Ovni Lab found the bypassed tone is fairly clean, so the switching is unlikely to color your sound noticeably.
Does the SMX have adjustable attack?
No. The compression attack is not adjustable. The pedal presets a fast attack for the high band and a slow attack for the low band, which shapes how each part of your signal responds.
Is the Trace Elliot SMX still made?
No. The SMX is long out of production, though it has a cult following among bassists and turns up on the used market. Trace Elliot has since introduced a new Dual Band Compressor pedal derived from the compression circuit of its TE-1200 bass amplifier.
Does the SMX have a gain reduction meter?
No. There is no LED or other meter to indicate when the signal goes over the threshold, so setting the compression is done by ear.
Sources (1)
- Trace Elliot SMX, ovnilab.com