Can you benefit from something that doesn't make a noise?

As musicians, we all have the problem these days of coming to terms with buying something that doesn't actually make any sound whatsoever. It can be very difficult, particularly when you could be spending the same amount of money on the latest instrument that is full of exciting noises.

However, more and more manufacturers are expanding the number of products in their range that spend life just interfacing one thing with another - they are important and you should consider their merits very carefully! A prime example is this latest Simmons product.

Whether you are actually interested in drums or not, you may find the new Simmons MTM particularly fascinating for its applications in the studio are far greater than that of simply allowing drum pads to control synthesizers.

The MTM presents you with the opportunity to generate control triggers from any audio source, be it live or off-tape, and apply these to MIDI synthesizers and sampling units. What's more, you don't even have to use drum pads to get the best out of an MTM, for its MIDI routing and triggering facilities alone would make it a worthy purchase for any studio.

So, just when you had finally decided to categorise Simmons firmly in the 'electronic drum' field, let me spoil it all by revealing how the MTM is breaking new ground for Simmons.

WHAT IS IT?

In its most basic form, the MTM is an 8-channel interface unit which converts audio signals into MIDI data and MIDI into trigger outputs. Nothing unusual about that. However, as we shall see, a little further investigation will uncover an enormous amount of facilities and applications.

As we are basically dealing with a dedicated computer, a vast selection of features are hidden behind the facia and like the Yamaha DX synths, the MTM uses a single LCD window to display all the various parameters which are called up for editing via the membrane selector switches. Similarly, this LCD window isn't illuminated either so you have to rely on good room lighting to let you see what's going on, though in fairness you're very unlikely to want to do any extensive parameter changing in a live situation, as you really do need to pre-programme the MTM.

UNDER CONTROL

The MTM is divided into three main sections. The Trigger In Sensitivity controls are positioned at the left-hand end of the front panel and allow you to control the input gain of a variety of signals at line or mic levels - there are eight individual controls, one for each channel.

After setting up the input levels, the signal moves on to the input conditioning section where it is looked at and electronically shaped into something that will result in useful triggers for controlling analogue or MIDI synthesizers. Finally, the Patch section allows you to manipulate triggers from any of the eight inputs by altering the MIDI data assignment and adding a whole host of effects to the output.

PATCH EDITING

There are a total of 119 Patches available and these are divided into 20 factory and 99 user programs.

A Patch consists of three main sections: Process-Route-Effect. In addition to these, two further items - namely MIDI and the SDS7 Selector Pad status - are also included.

We'll deal with the MIDI aspect in a moment after a few words on the Simmons SDS7 Selector Pad. Basically, if you already own a Selector Pad you can plug it into the MTM and use it as before but instead of just selecting 'drum kits' on your SDS7 it can select, via MIDI, programs on a slave synth as well.

Now back to MIDI. For a given Patch you can select the MIDI channel number (1-16) and MIDI program number (1-128). You can therefore set all the parameters that make up an MTM Patch to be identical except for the MIDI program numbers and so, when you're playing a song, you can change Patches and therefore sounds as you go. For instance, if you want a Caribbean flavour to a middle break, selecting a new Patch can cause the MIDI slave synth to call up a steel drum sound. After the break you could then return to a more pedestrian 'acoustic' drum sound and end with the sound of an explosion. You can do all this simply by changing the MIDI program number and nothing else - so you can really go crazy!

ROUTES

This section of the MTM Patch sorts out the internal connection of inputs to outputs for both MIDI and Triggers. Factory preset Routes 1 - 9 have been configured as straight-through so that Channel 1 input goes to Trigger 1 output and so on. The remaining eleven are variations on this routing principle, giving 20 factory settings in total. This leaves a further 79 routing possibilities available to the user. I think 99 different Routes is probably just about enough for most people! If it's not, don't worry, for there's a cassette dump facility for storing more programs to tape.

And whilst we're in the Route mode, this is where all the MIDI note information is programmed - and what's all that about? Read on...

For each Route, up to eight different MIDI notes (musical pitches) may be specified. This means that you can programme notes (and therefore chords) to play when a certain pad is struck and then when a new Patch with a different Route is selected, the MIDI notes associated with that pad may change as well. The result could be that the pad you have dedicated to the 'snare position' could, in fact, play a brass sound based on the root note of C and its associated note progression to form a C Major chord. You could then switch to a Patch which routes through a different combination and gives you a gong sound based on a lower octave A.

While on the subject of programming MIDI note information, it's worth mentioning that the LCD on the Simmons MTM usually shows the note in its chromatic form ie. C4, C4 etc. However, if you press the zero button on the calculator-style keypad, the note value will be displayed as a MIDI note number - ideal for the more computer minded - ie. middle C (C5) = MIDI note number 60. ( C# above middle C would therefore be 61.) Just a detail, but a very useful one.

You may have noticed that I said middle C was C5 when you might know it to be C3 or even C4. Well, believe it or not, it seems that although the world has recently agreed on a MIDI specification, it has not agreed on what octave middle C is in! Everybody counts the octaves from a different point. So, as it is agreed that middle C is MIDI note 60, when using the MTM it is often better to think in those terms rather than the more usual chromatic scale.

(This whole topic will be discussed in more detail in a separate article in the near future).

I've mentioned the Trigger routing in its simplest form already, but there is more. For each of the eight Trigger channels you can assign any Trigger Out to have any MIDI channel so that synths listening on different MIDI channels may be played via different drum pads. This is particularly useful for controlling multi-timbral instruments such as the Casio CZ101. Alternatively, all eight triggers can be sent on the same MIDI channel by pressing the 'All/Default' button if you want to produce the same sound but at different pitches ie. tubular bells on a Yamaha DX played across every pad.

EFFECTS

As the Simmons MTM is an intelligent interface, the task of routing data is a simple one. It's therefore no surprise to find that the designers have taken the matter a little further and produced a number of 'effect routines' that can be inserted into a Patch. In short, these Effects, as they're so logically labelled, are excellent!

Here's a rundown of what's available:

Echo: this is assignable to any pad and will send the echo data to both the normal Trigger Outputs and the MIDI Out. You can programme how hard you have to hit the pad before the echo effect comes in, the delay time before the repeat, the number of echoes and the percentage of decay for the repeat.

However, when controlling a MIDI synth you don't have to have the same pitch repeated in the echo if you utilise the following facilities:

Echo up in 1's: allows you to have each echo move up a semitone each time it repeats.

Echo down in 1's: is the same, but moves down in pitch on each repeat.

Now they're pretty exciting to hear, but not content with that the MTM also offers:

Sequence, echo-stepped: this enables you to programme a sequence of notes to be stepped through as an 'echo' rather than a simple up or down pitch progression and, as with the echo, you can control the number of repeats, decay etc.

Sequence, trigger-stepped: this is similar to the echo sequence except that you don't hear an echo triggered off one hit of a pad. What happens here is that you programme a sequence of notes and the unit automatically steps on to the next note in the sequence each time the pad is hit. Thus it becomes possible to play simple tunes.

Sequence, time-stepped: similar to 'trigger-stepped' mode, except that the sequence of notes is free-running. So when you hit the pad it sounds the nearest note in the sequence at the time of the strike. You can adjust the tempo of the sequence in this mode.

Sequence, auto-stepped: this plays the entire sequence through on receipt of a single trigger from the strike of a drum pad. The creative possibilities in this area are superb: you could, for example, programme a sequence up to a maximum of 16 notes, to form a link passage between the end of one song and the beginning of another.

In all instances, the sequences that are played have to be pre-programmed and this is done by entering the Edit Sequence mode.

PLAYING CHORDS

Within the Effects section you can also programme various chord options but these only operate on the MIDI output. The five modes available are:

- Split chord, dual-note.
- Split chord, multi-note.
- Layered chord, dual-note.
- Layered dual-chord.
- Layered chord, multi-note.

Each mode starts from a root note and either adds another programmed note to it when in the dual modes or, more interestingly, lets you assign any of 24 chord structures based on your original root note. These include Major, Minor, Augmented 5th and 7th etc, and it's in this area of chord playing that you can achieve some very big and powerful-sounding results, such as chord stabs a la Fairlight (assuming that you're hooked up to a sampler, of course). The possibilities within the chord options are very exciting. You can even do such things as utilise the dynamics of your playing technique to introduce varying amounts of notes into a chord structure.

PATCH SEQUENCING

Once you have programmed all your Patches you may wish to use a combination of them within a song, either live or in the studio, and so to make life easier the MTM lets you store the order in which you want to play the different Patches, as a Sequence. A total of 10 such Sequences may be stored and you can have up to 99 Patch choices per Sequence.

When you have the Sequence programmed, you can then start to play the song and advance to the next Patch by pressing one of the two footswitches supplied which let you move forwards or backwards through the Patch numbers.

Any Sequence can be edited at any time as little as one Patch within the whole Sequence, either by overwriting, inserting or deleting the data.

COMPLEX PROCESS

As Simmons so clearly point out in their excellent manual, the Process section of the MTM is by far the most complicated as it deals with the sensing of incoming signals and allows you to manipulate these in a number of ways, re-shaping them into different Trigger Outputs for driving either another 'triggered' sound module, such as the SDS7, an old analogue synth, or alternatively a MIDI synth.

This section of the MTM is essentially a 'gate' - though that's a bit of an understatement. It is, in fact, a very sophisticated gate that would be well-received as a piece of studio equipment in its own right (are you taking note Mr.Simmons?).

We're not dealing with a simple 'Is the incoming signal level below my set threshold? - No - Then I'll accept it as a trigger pulse' type of unit here! The Simmons MTM goes a lot further and asks the questions shown in the flowchart (Figure 1) before it will accept a sound as a bonafide Trigger.

To understand this process we need to consider the parameters the MTM will allow you to control.

You can set the threshold level that the signal must pass before it is recognised as a Trigger. This is called the 'Absolute Threshold'. If the threshold were set too low, any loud signal could trigger the unit several times within the space of its own decay period. The effect would be a multiple Trigger which is undesirable. The MTM therefore allows you to programme a Hold-Off time before it accepts another valid signal above the Absolute Trigger Threshold ie. a sound with a duration of half a second which repeats at one second intervals, could have a Hold-Off time of three-quarters of a second and therefore mask out any other signals for that duration. After the Hold-Off time has elapsed, the energy in the first signal will then be too low to re-trigger and so it results in good, clean Triggers generated off the first 'passing' of the Absolute Threshold.

Now, because you can programme this Hold-Off time to last up to a maximum of four seconds, you can use it to superimpose a different rhythmic effect on the incoming signal and that can be quite creative.

These functions of the MTM's Process section are not so very different from those found on a standard audio gate, however, the MTM goes further.

So, if you set an Absolute Threshold level and a Hold-Off time, what happens when the incoming signal varies its timing ie. it's random and not repeating every one second? Obviously you start 'missing' the Triggers you want whilst the Hold-Off time elapses. This is where the parameter'% Above Previous Threshold' comes to the rescue. With it you can set a percentage level of the Absolute Threshold, say 70%, so that any signal that comes along during the Hold-Off time that is above 70% of the original level will be accepted as a valid Trigger (Figure 2).

Well, that solves that problem, but here's another. If the signals are not all at the same level, ie. an acoustic drum can play quiet and then very loud, the resulting Triggers will be inconsistent. We've seen how the MTM copes with the variation in time between the Triggers and, yet again, it has a solution that sorts out signals of varying dynamics. This is labelled the 'Dynamic Hold-Off' parameter. What happens is that you can programme the MTM to automatically vary its Hold-Off time in proportion to the incoming signal level - quiet signals thus have a shorter Hold-Off time and loud signals a longer one.

The MTM can cope with a tremendous variation in signal characteristics and by careful programming of these parameters you can derive acceptable Triggers from almost any acoustic sound source - drums or otherwise.

There is even a parameter that allows you to produce a different sound by striking the rim or head of an acoustic drum without incurring any crosstalk problems. This is called 'Channel Compare Threshold' and works by comparing the strength of the signal energy coming from both parts of the drum when it is struck. If you have one mic pickup attached to the drum rim and another to the head, the signal present at the head pickup will be greater than the rim pickup for any strikes in the centre of the drum and vice-versa. The MTM detects which is the greater of the signals and accepts only one of them as the valid Trigger. This would therefore allow you to produce a different sound from rim and head strikes eg. a plucked string and a bowed string sound. The comparison between the two signals is programmed as a percentage difference and by programming a low percentage you can cause both sounds to play simultaneously off the one strike of the drum. It's all clever stuff!

THE WORLD OUTSIDE

Once the signal has passed through the Process section of the MTM, it is accepted as valid. You can then use this to do two things: generate a Dynamic Trigger output which may be used to control older analogue-type synths via their 'Gate In' socket and, generate a MIDI 'Note On' signal.

Now, as we're dealing with dynamic information this means that you can directly control the loudness of the sound produced by a touch-sensitive MIDI synthesizer - the harder you hit the drum, the louder the resulting synth sound.

That's OK but the MTM doesn't just offer such a simple relationship with the outside world. You can also impose twelve different dynamic curves on the output level and these control the loudness of the sound by either compressing or expanding it. These curves vary from the more usual one just mentioned to a reverse effect, where the harder you hit the quieter the sound, or one where only very soft strikes are quiet and anything else is loud.

Finally, within the Process section is the output signal control. There are two parameters associated with this - namely the 'Fixed' and 'Dynamic' Trigger pulse width. These parameters enable you to control the time the note sounds for and when using the Dynamic Trigger output, it allows you to programme the MIDI 'Note On/Note Off' signal to vary with the dynamics of the pad being played ie. the harder you hit, the longer the MIDI note.

That brings us to the end of the Process section. I did warn you it was complicated, remember?

IS IT FOR YOU?

Without doubt the MTM is a very powerful tool to have around the studio.

Throughout the article I have spoken mainly about using drum pads to play the unit. However, this was intended only as a point of reference as the MTM will process any audio source.

For example, if you had an acoustic drum kit already recorded on tape and you wanted to change some of the drum sounds, you could take the individual drum track outputs and process them though an MTM,then hook it all up to a MIDI drum machine and re-record the new drum sounds back to tape. Furthermore, you can do this for any kind of instrument where single notes are played. It won't detect chords though but it will playback chords of your choice on receipt of a trigger pulse.

The ideal type of synthesizer for use with the MTM would be any of the MIDI 'Expanders' that are on the market rather than one with an integral keyboard. Units that spring to mind are the likes of the Roland Planet S, Korg EX800, Yamaha TX7 and Chase Bit 01. Alternatively, you could opt for one of the rack-mount samplers.

If there is a problem with the MTM, it's not one of design, rather one of who Simmons are actually going to sell this unit to. The concept of electronic drums was successfully pioneered by Simmons, but the process of educating traditional drummers to appreciate the power of MIDI will, I fear, be a long one.

The MTM is going to be more readily accepted by people working in studio environments I feel rather than your typical 'live band drummer'. Even so, take a good look at an MTM and if you decide you can't justify having one. I'm sure it'll be a unit that the Hire Companies will go for.

One question remains: is anybody going to develop software to run on a Commodore, Apple or BBC computer that will bring all the MTM parameters up on a screen for swift editing, just like many have done for the DX, Casio and sampling keyboards?

The MTM costs £599 inc VAT.

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