Most professional DJ mixers available these days Pioneer's DJM-600 and Allen & Heath's Xone:92, for example have some sort of built-in effects or filter

Most professional DJ mixers available these days — Pioneer's DJM-600 and Allen & Heath's Xone:92, for example — have some sort of built-in effects or filter section offering basic tools like flangers, delay lines and filters that let DJs take direct control of the sound of their mixes. Barring a built-in processor, most pro mixers at least have some sort of send and return (often called an effects loop) for getting your tunes out to an external effects processor and back into the mixer at the flick of a switch.

Unfortunately, not everyone is lucky enough to own a mixer with these luxury features, and as a manufacturer of many such units, Gemini found a way to provide the entry-level DJ market with performance-oriented effects that can run in line with a mixer rather than on a loop. Gemini's DSP-1 features 12 different digital effects, a synth section and switchable line/phono inputs, doing away with the need for a dedicated effects loop and allowing it to be used directly in line between a pair of decks and a standard mixer.


The DSP-1 is an attractive unit with a small footprint that's easy to fit into an existing setup. The black front panel looks clean and uncluttered, with a single three-digit LED encircled by 12 selector buttons at the top and a large dial flanked by play/pause and channel-select buttons at the bottom. Two small knobs located at the left and right sides of the unit control overall volume and dry/wet mix, respectively. All buttons are backlit and rubberized for easy handling. The LED readout can display either the parameter value for the selected effect or the bpm of audio coming in to the selected channel.

Overall, I was quite impressed with the DSP-1's solid feel and quality build. The DSP-1 feels like it's built to last and seems like it would fare well if it ever had an unexpected encounter with a hard surface. The rear panel of the unit features four pairs of recessed, switchable line/phono jacks, two for input and two for output. Here, the DSP-1 really excels in its category: Most comparably priced effects units offer only a single line or phono input. A pair of decks or CD mixers can be plugged in directly to the DSP-1, which in turn can be connected to the inputs on a DJ mixer, eliminating the need for an effects loop.


The DSP-1 offers a selection of 12 digital effects. Most of the standard fare is present — flange, chorus, phaser, delay, echo and pan — along with a few extras such as fade; brake; and a complement of lowpass, bandpass and highpass filters. Notably absent is any sort of reverb. Effects are selected by pressing one of the 12 buttons around the LED display and engaged by using the play/pause buttons located near the jog dial. Only one effect can be selected at once, and the effect can be applied to either deck A or deck B, not both simultaneously. All of the effects sound decent, roughly on par with the internal effects in a DJM-600.

Each effect has one parameter that can be adjusted using the jog dial. Unfortunately, this parameter is hard-coded for each effect and cannot be selected; for example, the phaser parameter is depth, and the lowpass filter parameter is cutoff. The value of the parameter ranges from 0 to 100, no doubt giving rise to Gemini's boast of “1,200 parameter settings.” Although this is technically true because there are 12 effects, each with one setting ranging to 100, this bit of marketing hype seems rather misleading. The initial impression is of a highly configurable effects unit, but don't be fooled: The system offers little real flexibility.

Another unfortunate oversight is the lack of bpm synchronization. The DSP-1 does a great job of picking up the tempo of incoming music, and it seems like it would only be logical for the DSP-1 to take the next step and allow things like LFOs and delay times to automatically sync to tempo. For some reason, this is not the case. In fact, it appears that the bpm counter serves little purpose aside from exactly what it is — a simple bpm counter. It does not integrate with the effects or synth sections in any way.


When I first checked out the specs on the DSP-1, my curiosity was most piqued by the synth section. “How wonderful,” I thought, “to have an inexpensive DJ-performance unit that brings not only effects to the table but also a synth I can play in my performances!” In my mind, I pictured hooking up a controller and playing the DSP-1's synth via MIDI, sprinkling custom riffs over my tunes while spicing up the whole mix with effects.

Alas, it is not so. One of the first things I noticed when I took the unit out of the box was a lack of a MIDI port, which spelled doom for my fantasy. The DSP-1's synthesizer is a rudimentary drum-machine-style device with 12 sounds, one for each button at the top of the unit, featuring gritty samples that are lackluster at best. Further complicating matters, using the DSP-1's synth requires that the unit be switched out of Effects mode. That's right — you can either play the synth or use the effects, but you can't have your cake and eat it, too.

That might sound like a problem, but after hearing the synth sounds, chances are, you won't bother putting the DSP-1 in Synth mode at all. It's clear after just a few minutes that the synth section was more of an afterthought to this unit than a carefully planned performance tool. The sounds consist primarily of basic, low-fidelity drum samples, along with a smattering of pitched instruments like bass, piano and “wasp.” I was hoping that, at the very least, the drums might be fun to drop in on top of a mix, but, unfortunately, the samples lack any real oomph. Furthermore, the tonal sounds are completely worthless because they have a fixed pitch — you can't change them to match the key of your song. Even if you could, there's no patch storage for quick recall, and the DSP-1's three-digit LED interface would be too clunky to make that sort of change on the fly.


The DSP-1 doesn't have any sort of sequencer, but it does provide a rudimentary method of looping synth sounds. Simply press and hold one of the 12 selector buttons, and after about a second, the corresponding sound will begin looping on quarter notes. This might be useful if the DSP-1 had any sounds that I wanted to loop or if, perhaps, I could apply effects to the looped sound to beef them up a little; unfortunately, neither is the case.

In possibly the gravest oversight of the DSP-1's design, the bpm of the loop defaults to 120 bpm, regardless of what the DSP-1's bpm counter is displaying! The only way to loop the sound in time with your tracks is to check the bpm counter, then switch back to the synth parameter and manually dial in the bpm using the jog wheel. Even using this method, I was rarely able to get the loop synched with my music.

Overall, the synth section is a real disappointment and seems to have more in common with the “drum pads” on Casio's old consumer keyboards than with any professional drum machine or signal-processing device. If your main interest is adding fresh drums to your mix, picking up any drum machine — even something as basic as the Zoom MRT-3 — would serve you far better than the anemic drums on the DSP-1. Yes, you'll have to synchronize the bpm of the drum machine to your program material manually, but you'll have to do that with the DSP-1 anyway.


If you need a portable, entry-level effects unit that you can carry easily from gig to gig and don't care much about sonic flexibility, the DSP-1 might be a decent choice for you. It's well-constructed, and the effects sound good, though they are severely limited in their scope and level of control. The switchable phono/line inputs also offer connectivity options for mixers without dedicated effects loops.

The DSP-1 is not a bad unit, but there are a lot of alternatives out there that are equal or superior in many ways. If you're in the market for a DJ effects processor, think carefully about the features you need and take the time to compare and contrast all of the competing units in the DSP-1's price range. If you don't specifically need the pair of phono inputs on the DSP-1, consider all of the alternatives before you shell out your hard-earned cash.

Product Summary


DSP-1 > $319.95

Pros: Dual phono/line inputs and outputs. Small form factor. Well-built. Can be mounted on microphone stand. Bpm counter.

Cons: Limited effects flexibility. Poor synth samples. Monophonic synth engine. Synth and effects patches cannot be synched to bpm. Effects cannot be applied to both channels simultaneously. No reverb effect.

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