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Sony DPS-R7 Digital Reverberator

A New Reverb Standard

Article from Sound On Sound, December 1991

Hot on the heels of their impressive DPS-D7 digital delay comes the latest single effects unit from Sony. As the DPS-R7 reverberates, David Mellor adjudicates.



It's all go here in Mellor Studios. No sooner do I get the new Sony DPS-R7 home than the post lady arrives and pushes through my letter box a bulky envelope containing the latest issue of Sound On Sound with the DPS-D7 pictured proudly on the cover. If you read my review of the D7, which together with the DPS-R7 reverb represents Sony's first real push into the effects unit market, you might remember that I said it was probably the first of the new wave of single, as opposed to multiple, effects units. Multi-effects units have been justly popular in recent years, but once you have one in your studio why would you ever want to buy another? One decent multi-effects unit is enough for any studio, and soon we'll have a choice of dozens (hopefully) of classy single effects units, each of which does one particular job and does it very very well. Of course I am speculating, as I don't have an insight into the manufacturers' minds, but since I would very much like to have a better choice of quality easy-to-use effects units than exists at the moment, I see no harm in promoting the idea.

Physically, the DPS-R7 is identical to the DPS-D7, the only difference being that one letter in the name. There is a dual concentric input level control and there are separate stereo output level controls for dry and effect level. It's very useful to be able to mix the two on the unit itself, although most engineers will mix in the reverb via an auxiliary send on the console. The metering, as on most effects units, is adequate rather than wonderful but the 8-step LED bargraphs featured here are at least better than a good many of the level indicators I have come across on effects units. As LCDs go, the R7's is a very respectable size, very bright and clear too, and highly readable from one's normal position seated at the console.

Round the back we find what we like to see most on any piece of professional audio equipment: balanced XLR connectors. For dedicated jack plug enthusiasts there are suitable sockets too, with 14dB higher sensitivity. As a practising sound engineer for more than 12 years I can testify that most of my technical problems have been due to dodgy connections. Full marks to Sony for abandoning that dodgiest of connectors whose name I am not even going to mention. Also round the back are connections for a remote controller, but unfortunately there's no digital input or output. I'm very taken by the idea of connecting the digital output of an Akai S1100 to a quality effects unit like this and then perhaps chaining it still further in the digital domain. One day perhaps... (The S1100 does of course have inbuilt digital effects, but with due deference to the manufacturer of the world's most popular samplers, the reverb isn't quite up to the standard of the DPS-R7).

WORKING THE R7



Since most of us are human (?), I expect we'll follow human nature and use mainly the preset reverb programs on the DPS-R7. That's no bad thing of course — how else do you make a hit record other than by using only preset sounds and effects? There are two strategies one can follow in this non-editing mode of use: the first is to spin the dial and see what comes up; the second is to acquire an understanding of how the different types of program are made up, and then select from programs of the type you think will be most suitable.

The principal types of reverb program on the DPS-R7 are captioned as follows: HLR; RMR; PLR; GTR; ERF; and OFF. My Japanese leaves something to be desired, so the manual supplied with this early unit wasn't much use to me, but it's not so hard to figure out the abbreviations: Hall Reverb; Room Reverb; Plate Reverb; Gate Reverb; and Early Reflection. Guess what the last of the abbreviations means! There are also two types of delay which, as you might guess, are not quite as comprehensive as the delays found on the DPS-D7. There are 10 reverb algorithms in all, five mono-in/stereo-out and five stereo-in/stereo-out, using these various reverb and delay types. Just for fun, let's have a look at the block diagram of the stereo-in/stereo-out Plate Reverb effect (see Figure 1).

Figure 1. Block diagram of the Plate Reverb effect.


Fortunately, this part of the manual is in English. Does this look complicated to you? Well it looks complicated to me too, which means two things: that the DPS-R7 offers an excellent degree of control over the quality of the reverb signal; also that it's going to be difficult to edit. Well, not exactly difficult, let's just say that editing is going to be for editing enthusiasts rather than practical users who will probably just stick to tweaking the reverb time. This is perhaps the most complex of the algorithms, and other effects can be edited more quickly, due to their having fewer parameters.

Despite the wealth of parameters available for editing, never let it be said that a Sound On Sound reviewer was daunted. Let's examine Figure 1 in more detail and see exactly what control we have over the Plate Reverb effect. There are 97 parameters, so get ready for some fun...

Time Scale is an 'extra' parameter to make life easier for us all. It applies a percentage offset to all the various pre-delay and early reflection time parameters, described below.

Reverberation Time can be varied between 0.3 and 99 seconds.

Pre-delay 1 and 2. This innocent heading covers 18 parameters. If you look closely at the diagram you'll see that from the Predelay box on each channel sprout ten outputs. Two of these are the pre-delays which feed via the Spread box to the reverberation device. In the olden days we used to drive a real plate reverb from a tape generated delay. Things have certainly come on in the last 10 years! For each of the predelays you can adjust the delay time (by 1-22527 digital words), level (0% to 100%) and phase (normal/inverse), either in stereo or one channel at a time.

Second Pre-delay. Follow the lines from the Pre-delay box and you'll see what effect this has. It has the same adjustable parameters as Pre-delay 1 and 2.

Cross Pre-delay. In a real acoustic environment, ie. a concert hall, the sound bounces all around the auditorium and, assuming you are using a simple two mic stereo technique, some of the reflections which started off from the left hand side of the hall will find their way into the right hand mic, and vice versa. Cross Pre-delay simulates this.

Second Cross Pre-delay. As above. Both cross pre-delays have the same adjustable parameters as Pre-delay 1 and 2. If you have found it necessary to tweak all of these so far, you are about to turn to parameter number 48!

Early Reflections. Three early reflections, which are completely independent of anything mentioned so far, apart from Time Scale, sprout vertically from the Pre-delay box and bypass the reverb device combining directly into the outputs of each channel. Another 30 parameters.

Second Early Reflection. Thought you had enough early reflections? Think again — and there are Cross Early Reflections too.

Presence Control. This, as you can see, affects the entire reverb signal. It's a simple tone control which seems to operate on high mid frequencies.

Rotate High. Bearing in mind that I can't read the Japanese text in the manual, I believe this is what we would normally think of as high frequency damping. This is what it seems to do, and Sony would hardly provide all the facilities they have done and forget this important feature, would they?

Spread. This is very difficult to describe without knowing how it achieves its effect. I would recommend that you try it out for yourself.

Size. This simply sets the 'size' of the auditorium which is being simulated by a digital reverb simulating a mechanical plate reverb(l).

Quit. The last 'parameter', which takes you back to the editing menu, and by now it's probably time for a swift half down the local to recover!

Well, if you aren't impressed by this collection of adjustable parameters, then what will it take to impress you? I know I've always said that I want more control over the sound, but this much? Seriously, it really is good that those who want to experiment will have such a wonderful opportunity to play about with all the parameters that go to make up a lifelike simulation of natural reverberation, which in a real room is virtually infinite in its complexity. Future generations of equipment should provide an equal degree of control, but offer different levels of editing so that you can get in and adjust things like the reverb time and high frequency damping very easily and without distraction, and have an 'expert' edit menu so that those who aspire to a higher level of expertise can get more deeply involved.

EXTRA EFFECTS



Although I have described the DPS-R7 as a single effects unit, when you know what else it can do you might think that it's really a multi-effects unit in disguise. But the way these extra effects are presented is as an enhancement to the main function of reverberation, though if you so wish you can press the R7 into service as a digital delay, chorus, flanger, exciter, equaliser and autopanner too! When you think about it, these are the 'accessory' effects you would typically use in conjunction with a reverb unit, so their inclusion makes a lot of sense. However, don't expect all these effects simultaneously.

The accessory effects are divided into those which can be positioned before the reverb and those which come after, named Pre- and Post-effects respectively. Pre-effects include: Phaser; Flanger; Stereo EQ; Stereo Exciter; and Mono Exciter. Post-effects are: Gate; Phaser; Flanger; Stereo EQ; Stereo Exciter; Mono Exciter; and Autopanner. Each of these can really be considered to be a fully fledged effect in its own right. For instance, the mono exciter includes a 4-band equaliser with bass, treble and two fully parametric and fully overlapping mid bands. The other effects have as full a range of controls as you would want too.

SOUNDS LIKE...?



Pretty much like a real room, I'd say, although a totally realistic simulation will probably remain impossible for all time. Think about how many different reflecting and absorbing surfaces there are in a real room, and how many angles sound can strike these surfaces and mingle into the patterns of early reflections and reverberations. To mimic a real room perfectly would require almost infinite processing power. But although there can never be a perfect digital reverb, a high degree of realism can be achieved with appropriate control in the digital simulation over the major parameters which make up natural acoustic reverb — which is the case here. Feeding a completely dry source, such as the un-effected output of a synthesizer, into the Sony can result in a sound which gives the impression of the synth being played through a perfect amp and speaker in a real room or auditorium.

One of the real tests of a reverb, in my opinion, is how much of it you have to add to the dry signal to get the sound you want, which nine times out of 10 is extra 'thickness' and depth. With a poor quality digital reverb, which used to be all that was available in the early days of digital processing, you end up having to add so much processing to get the effect you want that the undesirable side effects become all too noticeable. The usual aim is to get a nice thick sound without it become over-reverberated which, with some units, particularly earlier ones, is very difficult. With the DPS-R7 I found myself dialling up preset programs and thinking, 'That sounds nice, but I can't hear the reverb.' Turning down the level of the dry sound revealed that there was actually quite a lot of reverb, but since it was so natural it became fully integrated with the dry signal, rather than obviously being signal plus effect.

In conclusion, this new reverb from Sony has the basic quality to put it in the same class as the Lexicon PCM70, by which I mean that one of the questions you ask when you book a studio could be 'Have you got a DPS-R7?', just as you might now ask, 'Have you got a Lexicon?'. Actually, this won't happen because Lexicon is regarded as being almost synonymous with digital reverb (and they have a very well regarded higher price product) so the name will roll off the tongue a lot more easily than a string of letters and numbers. But the quality of the new Sony is well up with the best and any studio would be proud to have a DPS-R7 in the effects rack as another choice for producers. Smaller studios will find no problem in using it as their main reverb; we'll be hearing the phrase 'Let's try a bit of DPS on that' in control rooms up and down the country for a very long time to come.

Thanks to The Synthesizer Company for the loan of the review unit.

FURTHER INFORMATION

£934.13 inc VAT.

Sony Broadcast & Communications (Pro Audio), (Contact Details).

SONY DPS-R7 SPECIFICATIONS

Quantisation: 18-bit linear.
Sampling Frequency: 40kHz.
Inputs: 2 channels, balanced XLRs (+4dB) and unbalanced phonos (-10dB).
Outputs: 2 channels, balanced XLRs (+4dB) and unbalanced phonos (-10dB).
Frequency Response: 10Hz to 18kHz +0/-1dB.
Signal-to-Noise Ratio: >90dB.
THD: <0.004%.
Memories: 100 Preset, 256 User.


MIDI CONTROL

As in the Sony DPS-D7 digital delay, you can control up to four effects parameters simultaneously via MIDI, with note number, note on velocity, channel pressure, or any MIDI controller. Parameters that can be modulated (on Plate Reverb programs) are:

Direct signal level
Direct signal phase
Reverb level
Reverb phase
Reverb time
Pre-delay 1 time
Pre-delay 1 level
Pre-delay 1 phase
Pre-delay 2 time
Pre-delay 2 level
Pre-delay 2 phase
2nd pre-delay time
2nd pre-delay level
2nd pre-delay phase
Cross pre-delay time
Cross pre-delay level
Cross pre-delay phase
2nd cross pre-delay time
2nd cross pre-delay level
2nd cross pre-delay phase
Early reflection 1 time
Early reflection 1 level
Early reflection 1 phase
Early reflection 2 time
Early reflection 2 level
Early reflection 2 phase
Early reflection 3 time
Early reflection 3 level
Early reflection 3 phase
2nd early reflection time
2nd early reflection level
2nd early reflection phase
Cross early reflection time
Cross early reflection level
Cross early reflection phase
Presence
Rotate high
Spread
Size
Stereo
EQ on/off
Bass frequency
Bass level
Treble frequency
Mid frequency
Mid level
Mid Q
Input level
Input phase
Input panpot
Input panpot limit minimum
Input panpot limit maximum
Output level
Output phase
Output panpot
Output panpot limit minimum
Output panpot limit maximum

On other reverb types this list will be different (but equally impressive!). Other MIDI functions include the on/off, omni on, MIDI channel, bulk dump and program mapping features normally found on modern MIDI equipment.


SONY DPS-R7 ALGORITHMS

PRE-EFFECTS BLOCK
1. Phase shifter.
2. Flanger.
3. Stereo equaliser.
4. Stereo exciter and ster^> equaliser.
5. Monaural exciter and monaural equaliser.
6. Gates.

REVERB
Stereo in/stereo out
1. Hall reverberation.
2. Room reverberation.
3. Plate reverberation.
4. Gate reverberation.
5. Early reflection.

MONAURAL IN/STEREO OUT
1. Plate reverberation.
2. Gate reverberation.
3. Early reflection.
4. Delay 1.
5. Delay 2.

POST-EFFECTS
1. Phase shifter.
2. Flanger.
3. Stereo equaliser.
4. Stereo exciter and stereo equaliser.
5. Monaural exciter and monaural equaliser.
6. Gates.
7. Auto-pan.


DPS-R7 PROGRAMS

The first 10 factory presets are the 'demo' programs, they contain in turn an example of each of the reverb types. Program 1 is a Hall Reverb type program titled 'Brilliant Hall'. It's smooth and bright, but you can hang thick drapes up by turning the Rotate High parameter, the high frequency damping, down from 0.625 to 0.3 or so. Program 2 is a Room Reverb type titled 'Studio ambience for drum'. This is a fairly small-hard surfaced room. You can easily make it bigger by increasing the Time Scale parameter which increases the time delays on all the pre-delays and early reflections. Program 3 is a Plate Reverb entitled 'Gold-foil plate' — it's only a digital simulation so let's make it 24 carat! This is a very dense reverb with only a moderate early reflection content, just as you expect from a real plate. There's no noise or hum though so perhaps the simulation isn't all that complete.

Program 4 is a gate reverb. I'm not so sure that gated reverb isn't getting a little bit old fashioned, but I'm sure the R7 is sufficiently well-built to last until things come full circle and there's a gated reverb revival. Program 5 is called 'Studio Ambience', an Early Reflection program. The Early Reflection program type has a delay line with 48 taps for each channel, each with adjustable time, level and phase. I hope someone is busy inventing a graphic editing software package for the Mac or Atari, otherwise this program just isn't going to be changed from its original state. It would take far too long. Program 6 combines two Plate Reverb programs, one set to a long reverb time, the other to short.

Program 7 is a bit clever, and combines a gated reverb with a reverse gate. This is more of a special effects program than a standard reverb, and could be fun when used on drums or percussion. Program 8 combines two Early Reflection effects, each with 23 reflections. Program 9 has two type 1 Digital Delay programs, and is good for making tricky echoes, as is Program 10 with two type 2 Digital Delays. The other 90 preset programs provide variations on the original 10 themes. Where you go after that is up to you, and you can go a long way with the Sony DPS-R7.


GROAN

This is an early unit, but I have to say that the knob didn't click as precisely as on the DPS-D7 digital delay I reviewed last month. Program selection was difficult, and sometimes the knob slipped to an adjacent program. Although there is a 'select then enter' mode of operation, so you can avoid changing program unintentionally, the review unit was not up to the standard of build quality Sony have set themselves. Hopefully this will be corrected by the time UK specification units are available. Ideally, I would like a detented knob as positive as the data knob on the Emu Proteus sample replay module.



Previous Article in this issue

Shape Of Things To Come

Next article in this issue

Dr T's X-Or


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


The current copyright owner/s of this content may differ from the originally published copyright notice.
More details on copyright ownership...

 

Sound On Sound - Dec 1991

Donated by: Bert Jansch / Adam Jansch

Gear in this article:

Studio/Rack FX > Sony > DPS-R7


Gear Tags:

Digital FX
Reverb

Review by David Mellor

Previous article in this issue:

> Shape Of Things To Come

Next article in this issue:

> Dr T's X-Or


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