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Sony DPS-M7

Digital Sonic Modulator

Following hot on the heels of the DPS-D7 and R7 digital delay and reverb units comes a third dedicated processor in Sony's DPS series — the DPS-M7. David Mellor wonders whether this marks the end of the line for multiple effects units.

I suppose that with hindsight it seems inevitable that Sony's DPS-D7 would be followed by further units in very similar looking cases, each performing one processing task to a very high standard. Sure enough, the review sample of the DPS-R7 reverb unit came in through my revolving door just as the DPS-D7 was going out. We have had to wait a little longer for the third unit in the DPS range, the M7 Sonic Modulator, which specialises in chorus, flanging, pitch-shifting and related effects, and hopefully a little investigation will prove that it was well worth the wait.

But is this what the world needs? Don't we already have enough effects units in our racks to provide all the phasing, flanging, chorusing and pitch changing we are ever going to need? And multi-effects units usually throw in delay, reverb and guitar effects for good measure! My feeling is that there is only so far you can go with multi-effects units. They are great when you are setting up a studio on a tight budget because they provide all the basic bread-and-butter effects sounds.

However, when you have one multi-effects unit, why would you ever want to buy another? Well, undoubtedly each multi-effects unit has its own individual strengths and weaknesses, so if you thought the reverb effect on your unit wasn't quite up to the standard of professionalism you were looking for, you might want to invest in something a little better. Another multi-effects unit perhaps? That would be just a little ridiculous, because you would be duplicating a whole load of effects unnecessarily just to get the one you wanted. I have in the effects rack of my personal studio a multi-effects unit from a well known Japanese motorbike manufacturer, and another which some may say is almost state of the ART. Neither are perfect, but each provides a good range of basic effects to a basic standard. At this stage I definitely don't need another multi-effects unit (in fact I only bought the second because I needed its distortion programs). When I can feel money bulging in my pockets again as the recession lifts, I shall be thinking about investing in high quality single effects units, such as these from Sony, and those which are undoubtedly on the way from other manufacturers.

The DPS-M7 is very similar in appearance to the other units in the range. This is both good and bad, because although it may look very nice to have a set of three stacked up in the rack all nice and neat, you could find yourself reaching for the wrong one.

Mega-customers who buy multiple units will also be investing in sticky number labels so they can easily identify each unit in their set-up. Is this really '90s hi-tech? As we shall see, Sony have been thinking along the lines of multiple set-ups of up to 15 DPS units.

The only external hardware difference between the M7 and its D7 and R7 siblings seems to be that instead of direct and effect output level controls there is just one effect output level, plus a 3-way switch to allow metering of the input, output, or a combination of the two. Let me run through the physical features of the machine first of all, just to see whether it's up to the normal Sony standard.

On the left of the front panel there is a shrouded mains switch which would be very difficult to operate accidentally. Not an original idea, but a good one which is obviously taken from Sony's high-cost high-quality broadcast equipment. Moving to the right we have a dual input level control, and the output level control and switch I mentioned earlier. It may seem like a small point but I am very much in favour of having output level controls on equipment. With both input and output level controls available, you can set your unit so that the peak signal input corresponds to the first red LED on the console's bargraph meters and so that the output is at the same level as the input. This means that you don't have to worry about setting levels on the unit (it's useful to mark the correct input and output settings with a Chinagraph), and you can have centralised control from the mixing console, which is the way things should be.

To the right of the controls are the bargraph meters, only eight steps, but reasonably accurate for effects use. The LCD display isn't as bright as those we are now seeing on portable computers, but it's probably bright enough, and it's a good size compared to what we were usually compelled to squint at in the past. Six switches and a dial, as on the R7 and D7, complete the front panel. The DPS-M7 has the added feature of adjustable dial sensitivity (doubtless software revisions to the other units will also feature this).

Around the back of the unit we find the optimum combination of connectors — XLRs for high-level low-impedance signals, and jacks with 14dB extra sensitivity and medium impedance for use with equipment working to the -10dBv standard. There isn't a high-impedance guitar input, so if you want to plug straight in without going through a mixer you'll need a preamp of some sort. Once again the only thing of importance lacking from this unit in the DPS series is a pair of digital inputs and outputs. I can't help thinking how pleasant it would be to digitally chain a DPS-D7, M7 and R7 to create a mega multi-effects unit, but you'll have to do this in the analogue domain I'm afraid. Also on the back panel are two 9-pin D connectors, to connect a remote control and allow daisy-chaining of the remote connection through a total of 15 units.


Enough of what the DPS-M7 looks like. How does it sound? What can it do? The sounds that the DPS-M7 can produce are probably the most extraordinary effects you've ever heard from a 19" rack mount box. But perhaps extraordinary effects are getting a bit passé, so let me re-phrase that: the DPS-M7 can produce some of the most extraordinary usable effects you have probably ever heard. In combination with the DPS-D7 and DPS-R7, the total effect build-up is probably something something like the difference between a solo violin and the London Symphony Orchestra.

I have often found chorus effects to be rather on the crude side, by which I mean that they provide a little bit of improvement to an otherwise thin sound, but not all that much, and the effect is too obvious. The chorus effects here are altogether different. One of the problems with synthesised sounds so far has been that the level of complexity of natural sounds is so vastly greater that synthesizers have come to depend on novelty value to entertain the ear. Listen to some old records to see how that novelty value fades, and a once ear-catching sound appears to be hopelessly old fashioned and uninteresting. In comparison, vocals, guitars and drums can still sound good, and interesting, on recordings going back to the year dot.

What synthesised and sampled sounds need is an increase in complexity so that they have an intrinsic value other than just being the latest sound from the latest synth. The Sony DPS-M7 can go a long way towards providing this complexity. A simple synth string sound may be pleasant enough by itself, but put it through the M7 and it will sound infinitely better — but not in an extreme way, just thicker, richer, more satisfying. It's like the difference between a pint of draught Guinness and ordinary lager. Now is possibly the time to look at Figure 1, which throws a little light on the capabilities of Sony's black box. Notice that there are are three chorus elements in each channel, three LFOs (low frequency oscillators), three predelays and three variable feedback networks with high frequency damping. Along with the other goodies, there is a good deal more available here than the basic rate, depth and possibly delay controls of the average basic chorus.

Figure 1. Block diagram of one of the DPS-M7's chorus algorithms.

There are other chorus programs that have up to five chorus elements per channel with individual LFOs. The result is a sound which is thick and interesting, without being too obviously chorused.

The sound quality of the DPS-M7 is excellent. Effects units have in the past often been noisy brutes, but this one isn't. 18-bit conversion, 48kHz sampling and a signal to noise ratio of better than 97dB see to that — but for that wonderful wash of Sonic Modulation you would hardly know it was there in the signal path.


Although the DPS-M7 is billed as a modulator, there are some ancillary effects as well as the chorus and pitch changing functions. (The pitch shifting function, by the way, understands harmony in major, minor, and several other musical modes). There are two pre-effects blocks before the modulation section, and also a post-effects block. How many pre and post-effects are available depends on the modulation algorithm selected, but let's look at some of these first before progressing on to the modulator itself, which is obviously the main item of interest.

Sony have used 3-letter abbreviations for many of the functions of the units in the DPS series, which is all very well when you have a proper English manual (as opposed to the review sample's Japanese one), so although I can explain most of them I'll have to guess at a few. The first of the pre-effects is called SEQ, a straightforward stereo equaliser with bass frequency and level, treble frequency and level, and mid frequency, level and Q (bandwidth) controls. Once upon a time you could have sold this as an effects unit in its own right. Here it's just a tiny little piece of decoration on top of the icing on the cake. Editing EQ with a dial is as tricky as it's always going to be, but Sony have made it a little easier by making it possible to edit both channels together if you wish. As an alternative to the equaliser, there is a stereo exciter with its own high and low frequency EQ with control over level and frequency.

If your music isn't reaching a satisfactory level of excitement even with the exciter, then you could try making it more dynamic too, with the dynamic exciter, which appears to alter the amount of high frequency emphasis according to the level of the source. The dynamic exciter doesn't have EQ. The penultimate pre-effect is the gate, with an impressive range of controls including trigger select (channel 1, channel 2, or both), attack time, release time, threshold level, hysteresis level and pre-delay. The compression pre-effect offers control over trigger select, attack, release, threshold, ratio, gain make up and predelay, but I wasn't able to find an algorithm that actually includes it. However, since it's in the manual, I'll expect to see it in an updated version of the software (the review sample was Version 1.03). Post-effects options are: off; stereo EQ; stereo exciter; dynamic exciter; gate.

The modulation section's effects are, as above, all described by 3-letter abbreviations. I managed to decypher all but one or two of these, so here goes: Stereo Chorus; Delay Chorus; Stereo Phase Shifter; Pitch Shift Mode; Reverse Shift; Ensemble; Manual Phase Shifter; Stereo Flanger; Modulation Delay; Spiral Modulation; Stereo Panner; Haas Panner; Doppler; Vibrato; Ring Modulator; Rotary Speaker. Among those I didn't get were: MCH (something chorus); BPH (something phaser); BPS (something pitch shifter); and MFL (something flanger). Maybe Sony will ditch all these cryptic abbreviations in future software revisions and just spell out what they mean. There is enough space in the display and it would make using the DPS series a whole lot more straightforward.

Rather than describe the basic modulation effects — which the DPS-M7 produces perfectly, without any unwanted noise and distortion — let me describe in a bit more detail the more unusual effects.


Mr. Haas was an acoustician who discovered a very interesting aural effect: if a sound arrives at the left ear first, the brain will think that the sound is coming from the left. More than that, if you simulate this with two speakers and a delay line, if the sound from the left speaker arrives at the left ear first then the level of the sound from the right speaker would have to be increased by as much as 10dB to make the brain think the sound was coming from the right. Ordinary panpots on mixing consoles don't do anything for the brain's direction sensing mechanism which times the arrival of sounds at the two ears; the Sony DPS-M7 does, with the Haas Panner effect. It operates as an autopan, and sounds subtly but interestingly different from a conventional amplitude autopanner (which the M7 has also).


The classic analogue ring modulator works by multiplying one signal by another, rather than adding them as in ordinary signal mixing. The result is an unpredictable and often cacophonous sound, but well worth experimenting with. If you like the sci-fi sounds encountered in old Dr. Who repeats then you'll like this. There are 99 parameters to play with, so get ready for a long session of experimentation. (Hint: try the feedback parameter.)


If by some stroke of good fortune you are asked to do music and sound effects for another series of The Hitch-hiker's Guide to the Galaxy, then you'll need this one. In the demonstration program the sound wobbles up and down in pitch, each wobble becoming larger and larger, until it contracts again ready to start over. For conventional musical purposes this is totally useless — but who wants to be conventional all the time.


Effects units which claim to have programs which simulate rotary speakers tend to exaggerate their capabilities just a little. Well, rather a lot actually. There is nothing to compare with the sound of a real live Leslie speaker for keyboard or guitar or whatever else you want to put through it. But since Leslies are rather bulky, it would be handy to have a reasonable imitation in a rack unit. Here the imitation isn't perfect, but it's a damn good sound in its own right.


Unfortunately, you won't get the full effect of this unit either from a review, which is all too short considering how much there is in this unit, or from the demonstration programs provided. The first 20 of the preset programs cover the full range of algorithms in turn, but to my mind too many of them are trying to impress with what weird and wacky things the M7 is capable of.

I would far rather hear, and have available for editing, a good selection of basic effects, done to the standard of quality that I know the machine is capable of. When you first meet the DPS-M7, you may look at it too superficially and end up suffering from the 'so what' syndrome; but I can assure you that if you experiment a little more deeply, and find out for yourself what it can do rather than indulge in mere preset hopping you will find that the relatively high cost of the DPS-M7 is fully justified.

Thanks to The Synthesizer Company ((Contact Details)) for the loan of the review unit.

Further information

Sony DPS-M7 £995 inc. VAT

Sony Pro Audio, (Contact Details).


If this unit was meant to be a dedicated pitch shifter then Sony would undoubtedly have called it the DPS-P7. If you want to buy such a unit then my personal recommendation would be an Eventide H3000 Harmonizer, which will cost you quite a lot of money and still not achieve the goal of perfect glitch-free pitch changing — but it comes pretty close. Pitch shifting on the DPS-M7 is best viewed as part of its arsenal of modulation effects. As I shall explain in a moment, it isn't just an instant transposition device but a powerful means of modifying the sound of synths, samplers, electric and acoustic instruments, and of course the human voice.

At its most basic level you can use the M7's pitch shifter to transpose a signal up or down in pitch by two octaves. If you want to produce musical harmonies then you can choose Harmony rather than Fixed mode, which will analyse the pitch of the incoming audio and shift it according to a musical scale. Those who were fortunate enough to have a modicum of musical theory drummed into them at school will recognise the musical modes on offer: major; minor; dorian; phrygian; lydian; mixolydian; aeolian; and locrian. As with all 'musical' pitch shifters, the input has to be very accurately pitched otherwise the unit will attempt to harmonise the wrong note.

At a more advanced level you can combine the pitch shifter with feedback (for Marvin the Paranoid Android effects) and when you reach the heady heights of Sony's ultimate pitch shift modulation effect — PSM — you will find yourself delving into pitch shift with modulation and delayed feedback combined with a very effective stereo chorus. It is this combination of effects that marks the M7 out from the pitch shifting crowd. Although you wouldn't want to use it in preference to a 'straight' (in comparison) unit like the Eventide H3000, because the basic quality of the pitch shifting isn't quite as good, the overall power of the DPS-M7 is very exciting, and should provide added spice to the recordings of anyone who gives it a try.


It may be just a small box with a few buttons, a dial and a display, but it opens up a whole new range of control for multi-DPS users. A 'multi-DPS' user is, by the way, someone who is fortunate enough to be able to afford several of these not inexpensive machines; perhaps as many as 15. The problem with rack units is that you have to go over to the rack to adjust them when you would rather be sitting at your mixing console or keyboard.

With the RM-DPS7 you can have full control over your set of DPSs with the merest twitch of a finger. Remote controls are not usually anything to get excited about, but this one really hits the nail on the head because it's exactly what you need. And if the one problem with the DPS series is that the dial is a bit tricky to operate, the remote goes one better because it has a pair of +/- buttons too. Not as good as a panel with real knobs would be perhaps, but it's an important accessory in the range.

Previous Article in this issue

Music On The Move

Next article in this issue

I Sync Therefore I Am

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - May 1992

Gear in this article:

Studio FX > Sony > DPS-M7

Gear Tags:

Digital FX

Review by David Mellor

Previous article in this issue:

> Music On The Move

Next article in this issue:

> I Sync Therefore I Am

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