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Alesis Quadraverb Plus and Datadisk SQ

Article from Sound On Sound, December 1990

Upgrading your equipment doesn't always mean selling the old stuff and replacing it entirely: new facilities and features may be only a chip away. Tony Hastings looks at updated versions of two Alesis units.

There seem to be two schools of thought amongst equipment manufacturers regarding upgrades. One is the all too common "Here's your box of tricks, but as soon as we've thought of something new, you'll have to sell your old one to buy it", the other is the less common but infinitely preferable "Here's your box of tricks, and as soon as we get a new idea we'll give you a very cheap upgrade on a chip so that you fit it yourself and benefit from the latest technology without taking permanent advertising space in the SOS classifieds!"

Happily, Alesis subscribe to the latter school of thought and have just updated two of their products: the Quadraverb and the DataDisk. Both these units have been fully reviewed in previous issues of SOS, so I'm not going to delve into the units' operation too deeply, just look at the way the new facilities are implemented and give you a first-hand account of how they work.


If you were to buy a new Quadraverb, it would now be called a Quadraverb Plus, giving you six extra effects. (Owners of earlier Quadraverbs can upgrade via a new chip for only £12.) These are: Multi-Tap Delay; Sampling; Auto Panning; Tremolo Modulation; Ring Modulation; Resonators. There are also improved real-time MIDI control facilities.


The new multi-tap delay gives you an unusual degree of control over the multiple repeats. The delay has eight distinct 'taps', each of which can independently be assigned a delay time, volume, and pan position in the stereo picture. There are two feedback parameters, one which sets the amount of feedback for each tap, and another master feedback control that operates on all eight together. The last tap is limited to up to 1500ms delay, and you have complete freedom to place all eight taps wherever you like within the 1.5 second 'window'. Multi-Tap is accessed in the 5BAND EQ PCH DL configuration and, like all the new features, it comes with new pages containing new parameters for you to edit.


Sampling in an effects unit is nothing new. I remember using an old Boss DE200 and a sustain pedal to capture and replay chunks of sound, back in the days when an orchestral stab was exciting stuff. The Quadraverb, however, gives you a decent degree of control over the sample once it's been taken, and of course it's 16-bit.

The sampling function is given a configuration all to itself (called Sampling, obviously enough), and pressing Delay takes you into the world of new sample parameters. The first aspect of sampling that you have to deal with is triggering. The Quadraverb lets you initiate sampling by pressing the Bypass switch for a manual trigger, or alternatively you can choose auto-triggering, whereby sampling starts when the input level rises above a threshold (in this case, the first LED on the input level meter). 1550ms later (the maximum delay time), the Quadraverb tells you that pushing the EQ button will replay your sample.

What you have now is a one shot sample, and a looping option is available to turn it into a sustained sound. You can edit both the start and end points of the loop - trying this on a sampled string sound, I found that eliminating the looping click was a pretty hit and miss affair. A lot depends on the sample you took to start with, and whether it lends itself to the process easily.

There are two other means of triggering a Quadraverb sample besides pressing the Bypass button: via MIDI or with an audio trigger. In MIDI One Shot mode, pressing any key on a controller keyboard will trigger the sample to play for its whole length, no matter how short a time you play the note (perfect for drum samples). MIDI Gate mode turns the Quadraverb into a monophonic sampler - the sample playback pitch tracks MIDI notes (you can define a keyboard range), and the Quadraverb will recognise Note Off messages as well as Note On. The Audio Trigger mode (handy for replacing one drum sound with another) can use only one shot samples - no loops.

Welcome though the sampling feature is, it's quite a simplistic implementation, so don't expect miracles. The looping is a bit too basic, and playing samples back via MIDI is fine until you start to move away from the original pitch. The manual does say that it's natural for the samples to change (munchkinisation and so on), but it only takes a few notes in either direction for the sample to sound a little too noisy and degraded. The Audio Trigger facility is useful, but you can only retrigger a sample once the input level has dropped below the -18dB level. This means that fast drum rolls will not trigger properly, for example, because there's not enough space between the audio events.


Auto Panning and Tremolo Modulation are available in both the EQ PITCH DELAY REVERB or 5BAND EQ PITCH DELAY configurations. You can only add pan or tremolo to the post-EQ signal, and the two effects are exclusive - if you select one you are unable to use the other. Both effects have only two parameters, Depth and Speed. Both function as you would expect, with the Pan ranging from a subtle sweep to a demonic helicopter effect, and the Tremolo accurately recreating the old Vox AC30 'wobble'.


Of all the new Quadraverb features this is the one I was most looking forward to. The others can be found in different forms on other machines, but ring modulation is definitely not the norm for most multi-effect units. A ring modulator is a specialised amplitude modulator that produces an output which contains only frequencies which are the sum and difference of the input waveforms' harmonics. It's particularly useful for generating metallic, bell-like sounds, or distorting voices into harsh Dalek-like tones. A pitched sound contains a complex mix of harmonics, all at different frequencies and levels. The pitch we perceive is the fundamental frequency, and all the other harmonics are usually even multiples of the fundamental. For example, say the fundamental was 200Hz, the second harmonic would be 400Hz (two times the fundamental), the third harmonic would be 1200Hz (three times the fundamental) and so on.

The audio signal that you are processing provides one of the necessary two inputs to the ring modulator, and the second is an internally-generated signal, whose frequency determines how much all of those harmonics are shifted by. There are two output signals: one consists of the sum signal (shifted up), and the other is the difference signal (shifted down), and you can vary the mix between these two outputs that is sent to the stereo output. Also, you can create an independent second mix to be sent to the DELAY/REVERB input, so there are two mixes of the ring modulator available. Ring modulation provides more fun than a barrel of monkeys, but it does have to be used with care. Changing the harmonic relationships within a sound in this way can lead to some extremely naff sounds, as well as inspired ones.


The Resonator effect provides you with what is essentially a pitch generator, a digital trip back to something not dissimilar to the legendary EMS Vocoder. Again, a new configuration page contains the new effect; RESONATOR DL REV. There are five resonators available, each of which will produce a pitch based on the pitch of the input. In Continuous mode, you can set a pitch (in semitones, from +36 to -24) and decay length for each of the five resonators, and in MIDI Gate mode the pitch differences for each are defined by incoming MIDI notes. The latter facility allows you to create 5-note chords from any input signal.


Full marks to Alesis for keeping the Quadraverb current and not letting the old users down. The new additions maintain the position of the Quadraverb, already a big seller, as a leader in the ever changing multi-effects field. My only real criticism would be about how you must make careful use of the sampling, and the fact that there was no distortion effect added. I use a Quadraverb for guitar, and so does just about every other guitarist I know, so a bit of distortion would come in handy. Having said that, all of the new features seem to be based on facilities already present (like pitch, delay and EQ), so maybe the hardware can't produce distortion, no matter how much you update the software.


Alesis' other new update is for their DataDisk, to the DataDisk SQ. To recap briefly, the original DataDisk could record MIDI Sys Ex dumps (including sample dump) and store them on 3.5" disks. This made it a great partner for things like the Alesis sequencer, or the M1, or anything that lacked its own disk drive for storing information. Unfortunately for Alesis, shortly after its release Elka launched the CR99, a product that did the same thing, but with the significant addition of recording MIDI sequence information in real time direct to floppy disk. Alesis rose to the challenge, and now a new chip is available (fitted as standard in new units) that expands the original DataDisk's capabilities to include recording real-time MIDI sequence information.


Operation is a doddle: first press the Receive button three times, then start the sequencer (or play live from your keyboard). As soon as the first byte of information arrives, the DataDisk goes into action, saving the data straight on to the floppy disk. When you finish, press the Do/Yes button, and the data is stored with a new file number. You must remember to record the sequence information with MIDI clock messages if you want to then replay the sequence from the DataDisk and sync a sequencer or drum machine to the recorded performance.

Because the information is written direct to disk, there is no loading time problem. All songs are available instantly, and there is no limit to the size of file that you can store, save for the limitations of disk capacity itself. I've been using one live for a month or so now, and it's sheer bliss not to have to make time in between songs whilst waiting for files to load. Songs can be loaded and used in any order, and you can even chain two or more together when you first record them, to ensure a smooth-running show.


Besides initiating sequence playback from the front panel, you can also use MIDI program change messages to start things off - very handy for live use, ensuring that you can leave the DataDisk in your rack, and control it from your master keyboard. The DataDisk will also sync up to incoming MIDI clocks, but again you must record clock data with the original sequence. The unit will also recognise Stop and Continue commands.


This has been a very brief look at the DataDisk, but to be honest there isn't a lot more to be said. When I first got it there were a few niggling points which I took up with a patient James at Sound Technology (thanks for the help).

First of all I found that when I stopped playback of a sequence halfway through a chord, there were problems with hanging notes - the DataDisk wasn't sending an All Notes Off command. This has since been rectified, and the fix should be available on software update 2.03, going out now. Also, the MIDI Thru facility is inoperable when in sequence mode, which is a bit of a pain.

Unless you have a MIDI patchbay, or some other way of merging data, this means that whatever is connected to the DataDisk's MIDI Out socket can be controlled either by a recorded sequence on the DataDisk, or by your master keyboard (or another sequencer), but not both at once. Apparently, there are as yet no plans to include merging as an update.

Another useful feature would have been the ability to read MIDI Standard Files direct from an Atari-formatted disk, but this is not to be either. Nevertheless, the addition of real-time recording to the DataDisk is a significant one, transforming it into a valuable tool for the gigging musician. I already own a Quadraverb, but after playing live with the DataDisk, I know that I'll never be able to go back to the old days of 'load and wait' again.


Quadraverb Plus £399 inc VAT (upgrade from original Quadraverb £12)
DataDisk SQ £349 Inc VAT (upgrade £12)

Sound Technology plc, (Contact Details).


Multi-Tap Delay: Delay, Volume, Panning, Feedback, Master Feedback.
Panning and Tremolo: Speed, Depth.
Ring Modulator: Spectrum Shift, Output Up/Down Mix, Delay/Reverb Up/Down Mix.
Resonators: Decay.

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Akai S1100

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Boxing Clever

Publisher: Sound On Sound - SOS Publications Ltd.
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Sound On Sound - Dec 1990

Review by Tony Hastings

Previous article in this issue:

> Akai S1100

Next article in this issue:

> Boxing Clever

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