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Sony DPS-R7 Digital Reverberator | |
A New Reverb StandardArticle 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.
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).
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.
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.
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).
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. |
Review by David Mellor
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