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Technics SH-GE90

Spatializer? What will they think of next?

[Technics SH-GE90]
[Italian version]

Product: Technics SHG90 parametric equalizer/spatializer - DSP
Manufacturer: Technics - Japan
Approx. price. 379 $/Euro
Reviewer: Dejan V. Veselinovic

Technics? What do they have to do with Hi-Fi, at least for the last 15 years or so? Equalizer? Yuck! Spatializer? Sacrilege!!!

Is it, though? Do you really think you're not listening to one right now? How many musical productions, be they on tape, cassette, vinyl LP or CD, have been made with no equalization applied?
I think none, none at all. Even the so-called "direct cuts" have some equalization of the microphones, if nothing else. And I don't mean amplification, I mean equalization. "Direct cutting" simply means that as little as possible and/or reasonable equalization has been applied, though there may be an odd work or two with literally no equalization.

Nevertheless, an equalizer is simply a tool, much like a hammer. With a common house hammer, you can idly crack walnuts, kill a person or construct a home, depending on how handy with you happen to be.
But because you can kill a man with a hammer, nobody will call it a lethal weapon and it won't be banned anywhere.
Much the same logic applies to equalizers - while it's true they are generally misused, they need not be bad by their very nature, even if inserting one in your signal path does defy the principle "the simpler, the better", or "less is more".

Anyway, Technics has come up with a very reasonably priced unit which defies categorization, insofar that it does several things at once, a jack of several trades.
First, it is a visual indication of musical spectra, and there are several modes of operation, such as normal, inverted, full or part of the spectrum and off.
Second, it is an active parametric equalizer, though I hasten to add not as complex as professional units (which do cost anything from 5 to 30 times its price).
Third, it can be used as a karaoke unit, something I am told turns on our Far Eastern fellow men.
Fourth, it can be used as a spatializer, or simply put, it can simulate various listening environments, such as cinema, church, hall, rock concert, etc.
On top of it all, it's completely digitally controlled, which means great precision, easy repeatability, excellent longevity through a complete lack of mechanics, and above all, memory.

[SHG90 Input-Output jacks]

You have a choice of inputs and outputs. You may use either Line In - Line Out or Tape In - Tape Out as alternative sources. Both may be adjusted.

Right, let's take it slower now. First, I completely overlooked its karaoke function. This is a mode somebody might be interested in if they want Eric Clapton to accompany them, but I respect Eric far too much to ruin his guitar playing with my horrible voice. Anyway, Lucio might not be so kind to me after that.

So let's take the spatializer first. This unit offers several preprogrammed modes, which you may use or disregard, as you choose. These modes are: Hall, Live, Disco, Church, Stadium and Theater. As far as approximations of general sound fields go, I'd say these were reasonable ones, but I think of them as examples or first aid kit to the uninitiated. Here's where memory comes to play.

There are five user adjustment sets which may be memorized. This allows you to create your own sound fields as your heart and/or instruments tell you. You can adjust the reverberation delay and frequency balance. Reverberation times vary as per preprogrammed equalizer modes, of which there are six: Heavy, Clear, Soft, Vocal, Headphone Stereo and Car Stereo. You can take any one of these modes, readjust it and memorize it as one of your own. I underline this as reverb time varies with selected mode.

Next, you can adjust the Q factor of the effect. Q factor is related to the width of your frequency adjustment - smaller numbers mean more narrow adjustment spectrum below and above the selected frequency, and vice versa. The Q factor is not a continuous adjustment as in pro equipment, but has two values - 1.8 and 0.7. 1.8 will give you a wide and 0.7 a narrowed down range. This is very useful in two instances which come to mind - adjusting possible room suck-outs and fine tuning speakers in difficult rooms.

Then comes the frequency. It has been split up into many individual center frequencies, these being: 31.5, 40, 50, 63, 80, 100, 125, 160, 220, 315, 450, 630, 800, 1k, 1.25k, 1.6k, 2.2k, 3.15k, 4.5k, 6.3k, 8k, 10k, 12.5k and 16kHz. That should be enough for most of us, I think. Each can be adjusted in steps of 1 dB up or down, for a maximum of +/- 12 dB. I should think all this would be enough for most of us.

Technics says its response is 15-20.000 Hz at -1dB, its S/N ratio is at -86 dB, THD is less than 0,08% at 1 kHz, and gain balance for each channel is (a rather poor for digital equipment) 1dB. It will output up to 6V, enough to drive any power amp into massive clipping, however, its maximum input voltage is a rather poor 2,3 V. This means it would be best to place it between the pre and power amp sections, or if your integrated has it, the external processor line. It will gobble up all of 17W from your supply line.

However you insert it, the front display will keep you well informed of all your choices and current status - it also has a reasonably good bar graph display, though I've seen better. It's a necessity for adjustment, but also doubles as a spectrum display of your current program, not at all a bad thing to have.

[Inside view of SHG90]

Inside, it's a rather tidy affair, actually much tidier than you'd expect for the price - but then, Technics has improved its layouts no end during the last decade.
Most control circuitry is handled by Sanyo VLSI (Very Large Scale Integrated circuits), with the usual sprinkling of 4580 op-amps around the place. Tweakers, take note - with a little patience, these beg to be exchanged for something more serious (like, say, OP275, OPA 2134, OPA 2604, etc).
There are also numerous discrete transistors around. The power supply doesn't look like much, the largest capacitor sporting a capacitance of merely 2,200 uF, the rest being considerably smaller. There are several three point stabilizers, but I wasn't very happy with the whole affair.

Its sound

Well, it was easy for me to compare the sound with and without the unit using the "External Processor" line on my H/K 6550 and monitor functions on HK 680 and Yamaha AX592; in operation, it's rather like a monitor circuit, press for inclusion of unit, press again for exclusion.
On basis of that comparison, I have to admit there's only a small difference with the unit in line than without it. However, after discarding the nasty cables supplied and replacing them with MIT Terminator 5 cabling, this difference became very hard to discern reliably at all. That is, no doubt, a good point.
This applies to the unit in its linear mode, i.e. with all effects and adjustments off. And with Van den Hul D102 Mk.3 cables with Neutrik plugs, the difference almost went away.

Just for a kick, I tried out all the preprogrammed modes. It would be unfair not to admit that Technics' approximations of various environments are rather good, if you're into that sort of thing.
Of them I think Theater and Church are easily the best of the lot, but if I ever used them, I'd do some fine tuning on both.

Then I got down to serious business. To my mind, equalizers are just that, devices used to equalize, make even. Armed with three microphones (two of which, both by Sennheiser, I dearly wish weren't borrowed, but life is cruel), two of which were recently calibrated and response diagrams included (thank you, my favorite local radio station), I set about measuring the response in my room.
Now, it's a relatively small room, about 14 sq.m, with a sofa, an armchair and double drapes - therefore, it all but sucks the sound in, especially in the higher range.
After much fiddling and fidgeting, I managed to equalize the sound on axis for room nasties. Of course, I was greeted with a sound much different to what I am used to - whether it's better or not, I honestly couldn't say. I do know it took me three or four days to get used to it.

In many ways, the sound was more open, more balanced than it used to be. I don't have a boomy bass, but even there, small adjustments helped make it more believable than it used to be.
"Believable" is the best term I can honestly apply here - I think most of us would need to make up our own minds whether it was "better" or "worse" after equalization.

Some recordings now sounded better than they used to, not so dark, with more light and shadow in the music, that I can't deny. So I went on and did some reverberation adjusting, or "spatializing", as Technics would put it.

The supplied ranges are fairly wide. As I discovered, my taste and the illusion of being there are best served with small adjustments rather than large - go overboard, and you get exactly the opposite, an overblown, surreal masquarade where a performance used to be. Totally plastic in some cases. You get ghetto blasting. On the other hand, to really get the best of this box, you'll need good electronics both up and downstream.

Playing with it, I used some otherwise muddy sounding CDs. Well, with a little patience and practice, you can really clean those up! It's very slow work at first, in part due to the idiotic notion of using semi-reflective plastic for a front panel, which makes things VERY hard to pick out, and until you get used to it, but progressively, it becomes easier to do and more fun.

This undeniable "fun factor" may raise the question - is this true audio? The answer is very hard to provide. In effect, everything we listen to is just a surrogate for what is only true, and that's live music. Compared to live music, everything else in our beloved audio is but an illusion. Accepting that, why should a device such as this be anything else but a compensator, a reconcilliator if you like, something that might enhance our audio illusions if used judiciously?

My last attempt to foil it was to insert it between Yamaha AX592's Pre Out and Main In lines. This mode is rather powerful, at 100W/8 ohms per channel, and has a very good mid range, but it also has performance falloffs at both extremes. Sure enough, the Technics cured all that and for the first time in its life, AX592 changed from a decent but strictly budget integrated amp to a semi-audiophile unit, if both of its defeat switches are engaged. Having lived with this amp for a year and a half now, I know its sound well, and under many circumstances and in many systems - it definitely sounded much better now, more firmness, almost true gusto (almost, but not quite), and a clean and extended treble, much less transistory than in the original. Very convincing stuff, that.

Like it or not, this unit CAN do so very much to enhance our overall listening pleasure, if, and I can't repeat this too often, it is used with moderation. If you feel you need to crank anything up, you're really saying that your system is not right, that something else is wrong somewhere else.

Compatibility issues

I'm somewhat worried by relatively low input margins; a more energetic CD player might well overdrive this unit. Therefore, it is very important that you insert it where it will do most good and least ill. If you have an "External Processor" input, you might try that place. However, I would recommend that you insert it between the pre and main power amplifier, if you have the option. Generally, input sensitivities of power sections are 1-1.5V, and every now and then a little over that, but also a little under that. Also, at 1V output, you'll be driving your power section into bliss and possibly clipping, so your actual signal voltage will be much below that, probably just peaking at 1V.


Technics SH-GE90 is a modestly priced unit, which cannot help but reveal its equally modest background. Its pretensions are relatively high, and it really can't be expected to meet its marketing goal, as THE solution. However, it goes a long way beyond what is usually obtained in similar units, or units which use classic single fixed frequency adjustment.

In the hands of a prudent user, it can improve whatever you already have, even take it to unexpected heights. It can clear up recordings, it can compensate your rooms deficiencies, in short, it can bring out the very best of your system. That said, don't raise your hopes too high - if there's a basic deficiency in your system, the best you can hope for is to cleverly conceal, but not remedy it.

It's a tweaker's joy, with all those el cheapo ICs for op amps. Note also that its power supply is split up - the small line filter and power transformer occupy a separate board - ideal to change it to something more serious, using a decent toroidal transformer. If you can get hold of its schematics, you might also investigate a better power supply as a whole, using quality capacitors, not to mention changing critical resistors, and such like.

By far the best thing about it is the spatializer - it cannot bring to life otherwise dead recordings, nor can it return grossly lost ambience, but it fairly surprised me how much better, how much more true to life recording can be. I hasten to add here that its best is brought out with SMALL step adjustments, backed by much patience and even more try-and-see attempts, and it's all too easy to overdo it. But, keep yourself and the unit in check, and you could be very pleasantly surprised.

For the money, it may be a boon - but that's up to you, it has the potential, it is you who must use it properly. Do give it a look. It's not into audiophile waters, but it can be a useful addition, especially for difficult rooms.

© Copyright 2000 Dejan V. Veselinovic - https://www.tnt-audio.com

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