How do you get an acoustic drum kit to sound like an electronic kit?
C-Tape solve this sticky problem with sticky transducers.

Rather than make the choice between electronic or acoustic drums, it's sometimes artistically preferable to have the facility to mix both types of sound, and this is exactly what C-Tape's Acoustic Percussion Trigger enables you to achieve. However, the APT does not create any of the electronic drum sounds itself, so just what function does it perform?

It works like this; you fix the C-Tape transducers provided to the inside of your drum shells and the control unit then derives both electronic trigger signals plus the acoustic sound of the kit. The trigger pulses will drive most drum synths, whilst the transducer outputs may be fed to a recording or PA set-up. So, one advantage of the system is that it allows the drummer to use his own acoustic kit to drive a drum synth. Also, of course, you can also pick up the acoustic sound of the kit without having to use any conventional mics apart from a couple of overheads to capture the cymbals and add a bit of ambience. As you might imagine, this set-up is equally valid live or in the studio.

C-Tape

The transducers themselves are based on the C-ducer design which is in effect a flexible contact mic in the form of a plastic strip with integral signal lead. In the case of this particular system, the transducer is fixed to the inside of the drum shell and held in place by means of double sided adhesive tape. They can therefore be easily removed or repositioned. The lead, which is fitted with a tiny plug, then passes through the breather hole in the drum shell and is connected to the input jack of the control unit via an adaptor plug.

The transducers are obviously made with the rigours of professional use in mind and the normally vulnerable point where the lead leaves the transducer tape is well reinforced.

Control Unit

These are available as two or five channel units and are attractively made and finished in a particularly fetching shade of green. The review unit was the five channel module but the facilities offered are otherwise identical.

The unit is mains powered and sports five identical channels, each of which have three controls and five sockets, three of the sockets being mounted on the rear panel. Firstly there's an input jack for the transducer, as you might expect, and also an unbalanced output from the transducer which carries the drum sound. On the rear panel is another transducer output, this time in the form of a balanced XLR connector and this is intended for use with mixing desks or recording equipment.

When it comes to driving electronic drums, there are two types that may be interfaced with this unit; the type such as Simmons and Ultimate Percussion that are fed from pads and therefore have some degree of dynamic control, and those that accept a fixed level trigger pulse level and subsequently have no dynamic control. In the latter category would be drum sounds set up on an analogue synthesiser that requires only a gate pulse to trigger the sound.

What the APT does not provide is a MIDI output which is rather an omission, as many of the new breed of drum machines could otherwise be played from this system.

The two types of output are provided on the rear panel in the form of unbalanced jacks, one carrying a fixed level positive going pulse and one carrying a signal that varies with playing dynamics. So far so good. Now onto the controls themselves.

Controls

The control layout is very simple and so even drummers should be able to operate it without suffering from technoshock. Firstly comes the Threshold control which in effect sets the sensitivity of the system and an associated LED lets you know when the channel is being triggered. The other two controls are level controls for the two types of trigger output so that APT can be matched up to the majority of drum machines in common usage. However, there is no front panel control for the audio output level as it is assumed that this will be used with some kind of mixer, but there is control over the output level via presets which are accessed through holes in the bottom panel. That's all there is to it.

Everything does just what you would expect it to do and there are no unnecessary frills to confuse the issue.

In Use

Installation of the system is straightforward but could take a little time if someone arrives at the studio with a double headed kit because you need to remove one head to get the transducers into place and then you have to strip the kit down again at the end of the session. This will be far less of a problem if you have a studio kit to which the transducers are permanently fixed, or at least a good snare drum. The C-tapes actually stick in place very well using the adhesive tape provided but are still easy to move when required. Purely in terms of sound, I would still prefer to use a set of good conventional mics purely from the flexibility point of view and raw C-ducers can sound a bit dull, but add a couple of ambience mics to capture the cymbals and it's a different story. These lift the drum sound enough to let it breath a little and you can get first rate results this way.

In terms of setting up the levels, this takes but a little experimentation to get the best results and the electronic drum kit of your choice will then trigger just as happily as it does from its own pads.

What is impressive is that the sum of the acoustic and electronic sounds can appear to be more than just the sum of the parts and careful tailoring of the electronic sound can yield some very satisfying combinations.

Using the straight trigger outputs with a synth also works without any problems but, because there is no dynamic control, the result tends to lack in expression. Nevertheless, this can actually be an advantage in some forms of music and you still have dynamic control over the acoustic drum component of the sound.

Trigger from Tape

A further use of this system and one that will surely appeal to engineers involved in all levels of recording is the possibility of triggering the system from drum sounds already recorded on tape and then using the trigger pulses to drive a more acceptable sound source. This means in practice that the horrible bass drum that has previously defied all attempts to make it sound like anything other than a suitcase can now be made to trigger something useful like a Linn bass drum which can then be used to completely replace the original on mixdown.

In practice, the system will do this without much trouble and it will resolve in excess of twenty beats per second in the presence of a clear signal which is fast enough for most pop work. Even with a little spill on the track from other drums, you can get a reliable trigger by careful setting of the threshold control and if things are a bit marginal, patching an equaliser between the tape signal and the APT can help to reject unwanted sounds and so reduce the probability of false triggering. This is not an application that the APT was originally designed for but several top studios have bought them for this very purpose and are apparently pleased with the outcome.

Conclusions

This is really one of those products that has been lying about for ages waiting for someone to invent it and C-tape just happen to have done it and done it well. The combination of the basic idea plus their unique transducer design has culminated in a system that is both easy to use and easy to set up yet does not affect the natural sound of the kit. As many drummers are still not happy about the feel of electronic drum pads, this system should please both the drummer and the engineer. Also, the possibility of triggering from tape, which is really a happy accident, may well turn out to be one of the APT's strongest selling points in recording circles. The lack of MIDI may be a limitation to some users but I'm sure that it is only a matter of time before a MIDI equipped version appears.

The 5-channel APT system costs £399 and the 2-channel system £259. Both prices include VAT.

Further details from: C-Tape Developments Ltd, (Contact Details).