From the shrill squeak of the soprano to the sepulchral tones of the basso profundo, the Eventide H3000 can create the full spectrum of human vocalisation out of the merest baritono ordinario. What's more, it has been to music college and knows all about majors and minors, chromatics and diatonics. David Mellor gives it an aural test.

In the good old days of music, pre 1900, if you were a promising boy chorister you could look forward to a long rewarding career in music. You didn't have to worry about losing your pure boyish tones when your voice broke, because at little cost you could have steps taken to ensure that it didn't! This type of singer was known as a Castrato, and believe it or not this is all true! Fortunately, boy sopranos in this day and age don't have to make the supreme sacrifice for their art. Instead, when their voice breaks, they go on to become TV presenters.

Should they not wish, however, to appear on the magic tube, there is always the possibility of keeping the pitch of their voices at a high level by surreptitiously using one of those ingenious devices known as a 'harmonizer' - the famous Eventide Harmonizer.

I have heard about, but not seen, a pitch changing machine which pre-dates the original Eventide unit. Apparently, it was a tape recorder with a rotating head. The head spun in the opposite direction to the recording on the tape, as it moved past, thus reading out the information faster than it was put in, but not changing the overall speed. I have also heard that it didn't work too well, and I am not surprised.

We should also not be surprised that electronic pitch changers don't always work perfectly. Changing pitch upwards means creating extra information from what is there already, to compensate for spewing it out too quickly. Changing pitch downwards means throwing some information away, or there would be too much to read out. Either way, the signal that goes in is going to get horrendously messed up before it comes out again.

We are now getting used to audio equipment that works perfectly. Take something like the complex, but common-or-garden, compact disc player as an example. There are many types available, but the difference in performance between different models is tiny. Similarly with other items, the scope for improvement is getting smaller all the time.

With pitch changers, the scope for improvement is still immense. First generation pitch changers produced all sorts of clicks, warbles and discontinuities which generally fall under the heading of 'glitches'.

To get an idea of what happens when a signal is pitch changed, get out your Yamaha SPX90 (I'm sure you can get to one somehow!). Program 21, 'Pitch Change A', is an easy one to try. If you play an instrument through it, notice how the sound becomes more garbled the higher up in pitch you go. Up to +2 semitones it's pretty good, above that it gets progressively worse.

Now try something percussive, like a drum machine pattern. Notice how the beats seem to come out a little differently every time - sometimes dull, sometimes delayed or doubled.

The SPX90, despite its low cost and variety of functions, is actually quite a good pitch changer. Certainly at less extreme settings, it is well on a par with much more expensive devices. Will pitch changers ever produce as smooth a result as changing pitch by speeding up a tape recording or transposing a sample? (These of course change overall speed, a pitch changer retains the original playback speed). Time will tell, but in the meantime any studio will want to have the best that is on offer. Eventide were the first to make pitch changing popular, so what does their latest model, the H3000 Ultra Harmonizer have to offer?

WHAT IT OFFERS

There is a definite trend towards multieffects units these days, and the Eventide H3000 is no exception. As well as pitch changing, it offers delay and reverb. The reverb isn't as awe-inspiring as some dedicated reverb units I have heard, but it has its own character and could be a useful addition to one's reverb armoury.

Like the SPX90 and other popular effects units, there are a certain number of factory presets (called 'algorithms') which you can alter to your liking and store in memory. The algorithms themselves, of course, cannot be erased. Since the proof of the pudding is in the software, a taste is required of what these algorithms can do. Let's look at one, Diatonic Shift, in detail and see what surprises Eventide have for the world of pitch shifting.

DIATONIC PITCH SHIFTING

Pitch shifting in the old-fashioned way was governed by frequency ratios. The pitch shifter would multiply or divide the incoming frequency by a set amount. For instance, a ratio of 2:1 means that an incoming 1000Hz tone would be shifted (multiplied by 2) to 2000Hz, representing a doubling of frequency and an increase in pitch of precisely one octave.

For smaller shifts it is sensible to use a ratio that represents one semitone on a keyboard instrument, roughly 1.06:1. This is one semitone up, 0.94:1 would be a semitone down. To programme a transposition of four semitones, a ratio of 1.06 x 1.06 x 1.06 x 1.06:1, or 1.26:1, is required. With a calculator, it's easy enough to work out. It's even easier if you use the table I have given in a separate panel. But modern pitch changers are tending to do away with ratios, preferring to measure intervals in semitones and cents directly (1 cent = 1/100th of a semitone).

So far, so good. But if you have successfully programmed a musical interval, and it's properly in tune, then your harmony will remain at that interval no matter what. Now this is great if you set the pitch changer to a musical fourth or fifth and you spend most of your time producing pseudo-oriental muzak. If you are more into western culture then this won't do. In the past there have been pitch changers with add-on keyboards to try to overcome this problem, but they haven't been all that popular.

Eventide's answer is to provide diatonic pitch shifting. 'Diatonic' is the fancy word for a scale using the white notes of a keyboard. What it means here is that you can set the H3000 to recognise and respond to particular notes coming in, and it will then pitch shift to notes that you specify. In other words, it can really harmonise.

In Diatonic Shift mode, the first thing the H3000 does is to analyse the pitch of the incoming note. Of course, this must be in tune or else the poor machine wouldn't know what it was supposed to harmonise to. Fortunately, the H3000 can be quickly tuned to any pitch you like.

Now that it knows the note it has to harmonise to, it transposes the incoming sound by the intervals of your choice, in the left and right channels. Since you are able to specify the musical key you are playing in, say C major, the H3000 will know that it must only produce notes C D E F G A and B. No sharps or flats. If you have set an interval of a major third (four semitones), then that will be corrected automatically to a minor third, when necessary, to keep to the correct notes of the key. An experienced harmony vocalist would do this without thinking.

Does it work? Yes it does. Setting intervals like this is the simplest way of using Diatonic Shift and they can be anything from one octave down, through seconds, thirds, sevenths, etc, all the way to one octave up. Alternatively, you can have the H3000 transpose everything to the same note, regardless of incoming pitch (you can have the tonic or dominant of the scale as high or low pedal notes - commonly-used musical devices), or it can respond according to user-preset scales.

The H3000's ability to set user scales is the most interesting feature of Diatonic Shift. Here, you can set a different pitch change interval for each different incoming note. By setting appropriate intervals for appropriate notes, you can input a melody and it will come out in perfect three-part harmony. The transposition range is increased to -2/+1 octaves.

Pitch Quantise is a clever feature of this algorithm. In simplistic terms, this means that if the input is 'playing in the cracks' between notes, the output will be adjusted so that it plays dead on whatever note it should be playing. This brings us to something interesting...

Suppose you set the transposition interval to zero, and set Pitch Quantise to On. Does this mean that you can sing into the unit and have your voice come out miraculously in tune? Well, almost. But you will need to be able to sing to an accuracy of +/- a quarter of a tone, or you will get shifted to the wrong note! Slight inaccuracies turn into definite off-key singing.

One way I found to use Pitch Quantise was to mix it in with the natural instrument or voice, giving a very interesting double-tracked effect that you can't achieve any other way.

PIANO SHIFTER

Diatonic Shift is the Eventide H3000's 'Big New Thing'. Loadsafun and a dead cert to be used over and over again on all types of musical material.

A more serious game is played by Algorithm 103 (sounds like the title of a sci-fi book). This is Eventide's latest word in how to do pitch changing well.

Algorithm 103 is a true stereo pitch shifter. 'True' because the processing functions of the two channels are linked so that what went in together comes out together. The pitch changing process takes a little time, depending on how complex the incoming material is. If the two channels were processed completely separately, there is the distinct possibility that they could get out of step from moment to moment, destroying the stereo image.

One of my favourite pitch changer tests is solo piano. A well recorded piano presents a sufficiently complex waveform to test any piece of audio equipment. At the same time, it sounds very clear to the ear. Any problems are easily noticed. The H3000 came through this test particularly well. In fact, when I first tried it I didn't realise that the piano had been transposed up by a whole tone! Listening more closely revealed the tell-tale warbling characteristic, but it was certainly very good.

Coming back to the SPX90 - my lower-priced comparison — its performance is almost as good at low ratio settings. It suffers more when you make the ratios a little higher - say, three or more semitones. The warbling sound is so pronounced that anything you put through it tends to sound more like the SPX pitch change program than the instrument you put into it.

The H3000, fortunately, is very good at the higher ratios (and so is the famous AMS digital delay/harmoniser). The important ratio for me is the octave. There are many occasions when it is nice to have an instrument doubled at the octave, either up or down. With the SPX90, it is not really a feasible proposition. With the Eventide it definitely is.

I have to say that perfect pitch shifting is not yet with us. By 'perfect', I mean that a stereo signal should sound as good pitch shifted as it would if it had been transposed by the musicians. I don't think we'll see anything like that this side of the millenium, but until then the H3000 is among the best I have heard.

MEGA MIDI

I just can't get enough of this MIDI stuff (song title?). There is no way it is possible to provide too many MIDI facilities on any item of audio or musical equipment. Even if it isn't practical to use all the facilities offered on every session, more facilities means more scope for experimentation. And there is more than enough scope for experimentation with the H3000 to keep a campus full of laboratories busy.

The expected MIDI Program Change facility is present, with full mapping capability. That's nothing new, but the range of MIDI control over program parameters is quite spectacular. Going back to the Diatonic Shift algorithm, several of its parameters can be controlled from the master MIDI keyboard, or by a sequencer:
Interval left
Interval right
Delay Mix left
Delay Mix right
Feedback left
Feedback right
Key signature

These are, in fact, all the performance parameters of the algorithm apart from Pitch Quantise on/off. I wonder why they missed that one out? The other parameters of the algorithm are those used for setting up purposes.

The Reverb Factory algorithm has MIDI control over:
Predelay
Decay time while gate open
Decay time as gate closes
Gate time
Mix

So with all these parameters to control, how do you control them? Well you might like to use a MIDI controller such as the Pitch Bend or Modulation wheels, or one of several other controllers that MIDI offers. Or you could opt for MIDI Note Number, the difference between two MIDI Note Numbers, Velocity (first note, last note, lowest note or highest note), Pressure, Release Velocity, or Number of notes held. Is that enough? No? How about MIDI Clock Frequency or Clock Period? This means you can actually have reverb time changing according to the tempo of the song!

A nice touch is that the changes you make via MIDI can be positive as MIDI values increase, or negative as MIDI values increase, and scaled as you wish. The upshot of all this is that you can have, for instance, a reverb which gets deeper the harder you play (obvious), or a pitch change that gets higher the more notes you hold down (experimental!). It is possible to have several of these MIDI parameter change functions on the go at the same time. The limiting factor appears to be the number of arms and legs you have to control them all.

The Eventide H3000 can also transmit MIDI messages of its own. Of course it can do System Exclusive bulk dumps, but it can also send, as MIDI parameter changes, sequences of front panel operations. So you could alter, say, a reverb decay time on the front panel with the sequencer running and this will be stored as MIDI data. Replaying the sequence will cause the H3000 to act as though you were running your fingers over its knobs and dials. Suppose you wanted a series of echoes, whose repeat time gradually increased then decreased over a four bar period. Conventionally, you would do this by creating programs for discrete delay times, then create a sequence of Program Change functions to achieve the effect. With the H3000, you can do it directly.

ONE MAN BARBERSHOP

With the Eventide H3000 Ultra Harmonizer you can be three-quarters of a barbershop quartet all by yourself. Diatonic pitch shifting is a big improvement over the old fixed ratio type. All the old favourite effects are available too - including simulations of previous Eventide units. The inclusion of reverb and delay is more than a thrown-in extra. The multi-tap delay algorithm is quite extraordinary and could easily form the basis of an effects unit in its own right.

But what is the price of all this. Surely it is going to be a hefty bit more than previous models of the Eventide Harmonizer? Would you believe that the H3000 actually costs less? It's still a fair old wad, mind you, but when you consider the amount of use it's going to get in a studio, it could be money well spent.

FURTHER INFORMATION

£1795 + VAT.

Marquee Electronics Ltd, (Contact Details).