Graphics equalisers designed specifically for use in a hi-fi system cost about half the price of those designed for studio use, but do they make the grade? Curtis Schwartz tried out for popular models

After a reader's enquiry about the price difference between 'equivalent' graphic equalisers from the hi-fi and professional fields, we felt it might be interesting to take a look at a few hi-fi graphics, and see if they come up to scratch in a semi-pro or home studio setting.

The four units we sorted out are the Akai EA-A7 (£160), Sansui SE-77 (£114), Marantz EQ340 (£99) and Technics SH-8045 (£133). These are four inexpensive units (by professional standards) that have very impressive specifications, and on paper would appear to be a bargain for the home studio. But are they?

A Graphic Equaliser by definition is an equaliser which uses small linear faders which permit manual control over a wide range of predetermined frequencies. They generally have two purposes in life: to compensate for room acoustics, and for equalisation of signals in a recording environment.

Therefore in this context we are putting units which are intended more for room acoustics compensation, and using them for signal equalisation.

Starting with the least expensive of the four, Marantz's EQ340, this unit is the chunkiest in appearance, yet would look least out-of-place in a recording studio. It has 10 bands per channel giving +10dB of boost or cut at 31.5Hz, 63Hz, 125Hz, 250Hz, 500Hz, 1 kHz, 2kHz, 4kHz, 8kHz, and 16kHz. These are fairly standard frequencies for hi-fi graphics to opt for — evenly spaced throughout the audio spectrum. When using parametric equalisers (either on the mixing desk's channel input or on ancillary equipment), one quite often finds oneself at these frequencies, and hence a carefully chosen graphic can be less limited than first impressions might suggest. Even so, the 16kHz notch usually ends up as being a hiss cutter, and frequencies of around 30Hz are typically for rumble bugs.

In Marantz's manual, they list the uses of each of the frequency bands, with such gems as 'raising this control will reduce air conditioner line noise' (for 63Hz) etc.

The Marantz's other front panel controls are for input selection (between Source, Tape 1 and Tape2), Copy 1-2 (for direct copying between Tape inputs), and Eq Record (for putting the equalisation in the record chain). Over on the left hand side are two more controls — for switching out the Eq, and for power on/off.

Below the central switching display are front panel female phono sockets for alternative inputs and outputs to the Tape Two channel, which is another very useful addition in a studio environment. This disconnects the back panel Tape Two sockets on the rear panel when used; and other connections on the back panel are straightforward enough — line in/out, and the two Tape Channels' in-and-outputs.

Construction is reasonable, though not the kind of item that could withstand too much abuse — an observation that befits most objects designed for hi-fi use.

Going up

Moving up a bit in price, we come to Sansui's SE-77 graphic, this time offering up to 12dB of boost or cut over 12 frequency bands. These are at 16, 32, 64, 125, 250, 500, 1k, 2k, 4k, 8k, 16k, and 32kHz. Switching between a 12dB and a 6dB maximum is provided and otherwise facilities and switching are almost identical to the Marantz — ie minimal. A glance over the spec sheet reveals a suspiciously outstanding frequency response from 5Hz to 100kHz (that's well above even cats' and dogs' hearing ranges!), along with a signal-to-noise ratio of 110dB, and distortion at 0.005%. Generally, hi-fi specifications should be looked at with a bit of scepticism from a professional point of view, as many of these measurements will be made under the most favourable of conditions and using the active circuitry for noise measurements (as passive circuitry will also be incorporated ie, perhaps two of the sliders being active, and the rest being passive). However, from a practical point of view, the quality of graphics should start from a minimum of having no effect on the signal quality whatsoever when Eq settings are flat, and any boosting or cutting should then be specific, and 'feel' accurate without affecting anything other than what it's meant to — ie, without clicks, hiss build-up etc.

Thus, Sansui's quoted bandwidth up to 100kHz etc is irrelevant, yet for all practical intents and purposes, it performs very well, and is of a slightly more robust construction than most hi-fi units. The sliders' travel distance being a little short makes the 12dB/6dB switching a useful facility, and otherwise Sansui's SE-77 graphic is a fairly straightforward unit.

Next step up in price is Technics' SH-8045 12-band per channel graphic, almost identical in features to Sansui's SE-77, yet with switching between 12dB and 3dB rather than Sansui's 12/6dB. It is housed in a very compact and slim case, and although this might look good for the fashion conscious hi-fi buffs, this makes the sliders' travel distance a little too fiddly for my liking.

The SH-8045's specifications are equally outrageous (5Hz-100kHz bandwidth...), and it certainly sounded fine... Construction is adequate, if again a little dainty, but nevertheless the Technics carries its weight audio-wise, and is without knobs protruding too much waiting to be broken off.

Gradually as we move up in price, we start to get into the flashing light territory. With Akai's EA-A7 seven-band graphic, we are most certainly in the looks department: fluorescent displays for curve and spectrum analysis, level metering, input selection, record routing, memory select etc.

Are you listening?

Did I say Spectrum Analysis? Yes, Akai does it all. It will simultaneously and individually display a spectrum analysis and graphic curve settings of the input signal, and you are quite right in observing that I also said "memory select". There are three programmable memory curve settings, which is not the gimmick it appears to be. All of these facilities, though not what I would buy a graphic for, I found very useful. I found myself using the three memory settings for a snare's Eq whilst I had to reroute the graphic for a last-minute bounce, the bounce's Eq in case it had to be redone at any point, and a quasi noise reduction effect for a mixdown which needed further Eq when being chucked from two track to two track. This last possibility was easily accomplished with the Akai's reverse switch for the graphic settings. Thus I lifted the top end a little for recording, and then reversed it for playback, thus cutting down on a little hiss.

Just before I completely forget the basics of the Akai, it offers only seven bands per channel with 10dB of cut or boost at 63, 160, 400, 1k, 2.5k, 6.3k, and 16kHz. Although limited in choice in comparison to the other graphics we've had a look at, these are very cleverly chosen frequencies, and in fact when used in conjunction with parametric Eq (as most of these should be) the Akai proved to be as versatile as the other graphics. The microprocessor control of almost all functions doesn't appear to do any harm to the signal quality, and this is certainly a unit which says 'look at me'. Watching the Spectrum Analyser in action is not simply a toy; I found it useful to refer to when listening fatigue started setting in an overlong session, and equally useful, if only psychologically when working on individual sounds.

Incrementation of the graphic is achieved by pressing the seven tags under the display in conjunction with the left/right selector. This produced no problems, and overall the usability of the Akai's controls seemed to be very good. Having said that, I would be happier using boring old sliders in a studio environment — if only for a greater sense of 'security'.

Conclusion

It is very possible to spend £1,000 or more on a pro audio graphic equaliser. Without naming any names, what this extra cash will buy you is robust construction, tough knobs, and something that feels professional. Therefore, in a budget environment where your typical £200+ graphic would not be a high priority on your shopping list, one of these £100+ graphics might well be a better bet. I am hesitant in making any sweeping generalisations however, as many people have different views on the role of a graphic equaliser in a studio — many people dismissing their usefulness completely as items where the money would be better spent elsewhere; certainly their place in your average hi-fi is debatable. Yet in a home studio, where the need for reasonable outboard Eq is important, the possibility for such units should be looked into.

The Marantz and Sansui graphics are straightforward and inexpensive. Technics make a whole range of graphics of which the 8045 is a good middle-priced example, and quality high tech is to be found in the eminently usable Akai EA-A7.

There is life outside pro audio.