MIDI Programmable Mixer
A programmable mixer that will find a good home in a home studio.
Steve Howell discovers that there's more to Simmons than than electronic drums. The SPM8:2 programmable mixer may well become a home studio standard.
The two mainstays of the recording world, the tape recorder and the mixer have remained, until very recently, largely unaffected by the microprocessor revolution, excepting features like digital tape counters and transport controls, and what progress has been made tends to carry a 6-figure price tag. Digital tape machines and computerised mixers were strictly the sole province of the mega-studio - until now that is. While we may have to wait a while for a home studio digital multitrack recorder, automated mixing is already here.
From an unlikely source comes a new, totally programmable mixer. The manufacturer is Simmons, inventors of the drum synthesiser. The SPM8:2 MIDI Programmable Mixer was initially conceived as a partner to MIDI electronic drum kits and the sound processors used to treat them, but it very soon became clear that the bulk of the interest was coming from keyboard players who were in a better position to appreciate the advantages that MIDI-controlled mixing could bring.
Though it doesn't look much like the mixers we're accustomed to working with, the SPM8:2 is internally configured rather like any conventional console, but there are one or two additional features thrown in for good measure. It has eight input channels (line inputs only) and each channel has conventional gain, EQ, aux sends and pan controls. In fact the EQ section is a 3-band affair with a sweepable mid and there are two post-fade auxiliaries for use as effects sends. On top of this there is LFO modulation of the mid range equaliser for wah wah effects, autopanning and crossfade, more of which will be said later.
Unlike the top end automated mixing consoles which remember every move you make during a mix, the SPM8:2 works on the snapshot principle. When the user sets up a mix, all the gain, equaliser and auxiliary settings are stored as one of 64 memory patches and these patches can be compiled in sequence to handle the mix of a complete piece of music. They work in exactly the same way as the program patches on a keyboard synth and can be called up remotely at any time and in any order via MIDI from a sequencer or other suitable device. In addition to storing the usual mixer parameters, though, these patches include the programming of the auto-panner and the dynamic EQ section. The only parameters impossible to program are the input gain trims and the master output and headphone levels. These are controlled by conventional rotary potentiometers.
All these programmable features are implemented using digitally controlled analogue devices, but the signal is not digitised as it is in the far more costly Yamaha digital mixer. In practice, these voltage controlled amplifiers and filters can introduce more noise and distortion than their non-automated counterparts if careful design procedures are not followed, but even bearing this in mind, the SPM8:2 fares very well, I'm pleased to report. Simmons are well versed in designing VCAs and VCFs into their equipment and all the tests I tried sounded good to my fairly critical ears. As for distortion, the figure quoted is 0.2% in the spec sheet, which may seem a bit high on paper and might put some purists off, but one's ears are the best items of test equipment for evaluating sound and I could hear no appreciable loss of quality even under demanding studio conditions. Live, where distortion figures can run very high anyway, this would go totally unnoticed. In other words, the SPM sounds good and clear, just like any other 'conventional' mixer in fact. Loudspeakers and analogue tape recorders can introduce several per cent of distortion, so this figure poses no problems. Actually, some types of distortion are far more audible than others and we've asked our long-suffering expert, Ben Duncan to string together a few lines on the subject for your edification so keep watching these pages.
But no doubt you're itching to find out how it works.
"On the SPM, we only have controls for one channel, which can be assigned to any of the eight channels as required."
Looking at the photos, you may well be thinking that we've mistakenly printed a photo of one of Simmons' SDE drum expanders or something similar; it seems far too small to be a mixer. In fact, what you see is the world's first full function 8-channel stereo mixer in a 1U rack mounting box. And it's here that you have to make the biggest mental adjustment. We're all used to having huge consoles sprawling in front of us, but we all know that every mixer is essentially one channel duplicated X number of times. On the SPM, we only have controls for one channel, and these may be assigned to any of the eight channels as required. Admittedly it does take a little getting used to, but it's not a major hassle. Besides, most engineers tend usually to work on one channel at a time, so it does make ergonomic sense. It also keeps the cost down considerably. The main problem is that the current control positions don't necessarily relate to the settings of the channel currently being listened to.
The controls available are Level, Pan, FX1 and FX2 sends (both post-fade), Bass cut/boost, Mid cut/boost, Mid frequency and Treble cut/boost: all standard stuff to anyone who has used a mixer before. There are a few other controls, though, that make the SPM a world first. Each channel has its own autopanner for a start. There are three controls associated with this section: LFO speed (the rate of autopan), LFO Amount (the depth of autopan) and a 4-position Mode Select. Mode 1 offers straight autopanning, Mode 2 routes the LFO to the mid frequency control which produces waa-waa-like effects with mid boost and phasing effects with mid cut (no effect, of course, with no cut or boost). Mode 3 uses signal dynamics to control the stereo position of the sound whilst Mode 4 uses signal dynamics to control the speed of the mid frequency sweep. Of these, Modes 1 and 2 are the most useful although Mode 3 is great on sounds with extremes in dynamic range. Interestingly, this Mode select control is not switched as one might imagine but is continuously variable so, by positioning the control in between two modes, a combination of effects can be used. Particularly dramatic was a mix of Modes 1 and 2 where the mid frequency sweeps also panned back and forth. All this panning stuff may look a bit gimmicky, and I suppose it is, but it's there if needed, and it's possible to use it tastefully.
The final input channel control is the channel crossfade time: in other words, the time it takes for one mix to change to another. What's good is that each channel's crossfade time is totally separate so that, for example, channels 1, 2 and 7 could crossfade instantly while channels 3 and 4 could fade out slowly and channel 5 fade up even slower. Crossfade time is variable between a few milliseconds and ten seconds and makes up for the fact that this is a snapshot system rather than full automation. By carefully programming the crossfade rates, a mix can contain dynamic level changes of the sort that can normally be achieved only on the most expensive automated systems.
The other programmable functions on the mixer are the effect returns, of which there are two, and the effect return pan controls. There are separate controls for left and right master outputs. Personally I'd rather have seen one dual ganged control for better stereo imaging and easier manual fade outs but I can live with it.
"I could hear no appreciable loss of quality even under demanding studio conditions..."
The centre of the panel is taken up with a few switches that program the unit. 64 mixes (or 'patches' as Simmons call them) can be stored in two groups, each comprising four banks of eight patches. These may be selected using an up/down incrementor on the front panel, using a footswitch or, more usefully, via MIDI patch change. There's a large numeric LED that shows a patch number (1 to 8) and there are four LEDs that tell you which of the two groups you are in. While this is satisfactory, I'd rather Simmons have dispensed with the four bank LEDs and use the space thus provided to make way for a dual numeric display that would show 1 to 64 which would be far easier in use. Furthermore, the user has to step through the patches to get to the right one; it's impossible to call one up directly except via MIDI.
Other switches are Channel up/down with which the user can select a channel, and underneath each of the first eight controls are LEDs which light up to display the channel currently selected. By incrementing beyond channel 1 or 8, all the LEDs go out and the first eight controls then take on their dual role as channel faders for all eight channels simultaneously. Any settings made in this mode are remembered by each channel.
The procedure for programming a mix may go something like this. First, set up each channel's parameters (EQ, pan, LFO and crossfade) separately and then call up the eight level controls and set your channel balance accordingly. That mix can then be stored and you can move on to the next section. Storing a mix is simple (using the Store control would you believe?). Channel settings can even be copied to another channel in another patch, and patches can be copied into other patches, provided that they're in the same group.
It's possible to address the SPM8:2 on individual or all 16 (Omni) MIDI channels, although it responds to patch change information only. It might have been nice to be able to address individual patterns via a synth's data entry slider but this would make the unit unnecessarily complicated.
"By carefully programming the crossfade rates, your mix can contain dynamic level changes of the sort that can normally be achieved only on the most expensive automated systems."
Round the back of the unit we find eight line inputs (which are not suitable for microphones), and a small non-programmable gain trim control for each channel. I'd rather have seen the gain controls on the front panel as it's impossible to get at them once the unit is in a rack. I know there isn't room for them but that's not my problem, I didn't design it. All the other ins and outs are on the back, as is the mains switch.
All patch change information can be stored onto tape (cassette or reel to reel) but, in common with other Simmons products, the tape save/load inputs and outputs are made available on the MIDI In socket. This is a great shame, especially if the unit is rack mounted as it's impossible to change the plugs around. I intended to bring up the tape save/load sockets on my patch bay and then store the mix data onto a spare track of the multitrack so that I could remix that same tune very quickly and easily at a later date. With the system configured in this way this proved to be impossible, and I feel that Simmons have fallen into the common trap of designing a bit of rack gear with the ergonomic consideration normally applied to a piece of free standing equipment.
In use, the SPM has a variety of applications in addition to those for which it was originally intended. Live, in conjunction with a programmable MIDI patchbay, changing a patch on your master keyboard will change all the patches on other synths and expanders, reconfigure the MIDI set-up and set up a completely new mix for that particular combination. Of course, if you have MIDI effects the sound processing can be changed as well: pretty powerful stuff. Now for the first time, a keyboard player with a big set-up can actually concentrate on making music, not spend his time worrying that he's pressed the wrong button. There's nothing to stop you using a few SPMs to handle other line signals such as drum synths, drum machines, lines out from guitar amps and the like, and setting up a completely pre-programmed PA mix with the sole exception of the microphones.
In the studio, there are even more possibilities. I've been using the mixer set-up primarily as a monitor mixer and then, when the piece was finished, using the SPM for final mixdown. By programming in mix patch changes to my QX5 sequencer and then syncing that to tape, I had totally automatic mixdown and could sit back and listen to the mix instead of having to concentrate on making the right control changes at the right time. Also, not having to tie up my existing mixer meant that I could accommodate sequenced synths during mixdown, thereby ensuring first generation drums and so on, effectively expanding my 8-track to as many as 24 tracks or more if I used the FB01's and the ESQ1's multi-timbral facility.
"I'd rather have seen the gain controls on the front panel as it's impossible to get at them once the unit is in a rack."
At a simple level, a few synths, samplers, a drum machine or whatever can be played through the SPM, with everything being run off a sequencer direct onto your stereo master.
I was very impressed with the SPM8:2. Having got over the single channel access I found it quite easy to use, though it is a bit awkward on occasions as it's not possible to see what other channels are doing. Had Simmons provided a MIDI Out with System Exclusive, it would have been possible to hook it up to any bog-standard computer and display all eight channels on a VDU with the aid of a little more software: another missed opportunity, I feel. As it is though, it's remarkably easy to use as long as you know what you are trying to achieve and keep your wits about you.
It's quite an exhilarating experience listening to a piece mix itself, with different sections mixing smoothly into another, especially when driven from a sequencer that's synced to tape, and I calculated that at one point I would have needed 17 hands just to go from one section to another! In that respect, the SPM opens up new avenues in creative remixing as the user can set up nix situations that would otherwise be impossible; the type that are normally handled by splicing sections together. By closing down empty tracks in a mix, the master's signal to noise ratio can be significantly improved, and the SPM is ideal for dub mixing where any number of channels can be muted or opened with the press of just one button. Also, using the effect sends, it's possible to add an effect to just one note far more easily than it would be on most 'conventional' mixers. Another big advantage is the programmable crossfade system which neatly sidesteps many of the disadvantages of a snapshot system with its abrupt patch changes.
I've already mentioned a few criticisms, but I feel that if Simmons had housed the unit in a 2U box, the front panel could have made room for the channel gain trim controls, the tape dump socket and the power switch, and this still would make for a little less cluttered front panel. There would also have been more room for the programming switches which could have cut down the number of multi-function options that exist at the moment. The enlarged back panel could have then made way for other useful facilities such as insert points, separate tape ins and outs and more in the way of MIDIing. This, however, might well have added a lot to the cost so maybe it's just as well they called a halt when they did.
"It's quite an exhilarating experience listening to a piece mix itself, with different sections mixing smoothly into another, especially when driven from a sequencer that is synced to tape."
As it stands the SPM8:2 is a major step forward in mixing technology and design and points the way forward for small automated consoles. Currently, it has little in the way of competition though there are new products from Akai and Yamaha due soon.
Whichever way you look at it and however you plan to use it, the SPM8:2 is a very flexible piece of equipment which is surprisingly cost-effective, especially when considering its onboard facilities. You could only just buy eight autopanners for the same money. None of us can afford to ignore automated mixdown, even in a simple home studio and, until something else comes long, the Simmons SPM8:2 is the most cost-effective way of obtaining it. Check one out. You'll be impressed.
The Simmons SPM8:2 retails at £599 including VAT.
Review by Steve Howell
Previous article in this issue:
Next article in this issue: