Loudspeakers are the most problematic of all the pieces of equipment in a hi-fi system.

Why?

Because they perform the most difficult function of turning electrical signals into sound.

This is no easy task. Compared to what a loudspeaker has to do the function of an amplifier is a doddle.

If you want proof of this look at the distortion figures from typical amplifiers and loudspeakers. Even if we analyse only harmonic distortion, the typical modern amplifier distortion is in the region of a fraction of a percentage. Whereas that from a loudspeaker can often be measured between 3 - 5%.

Why, then, do we not cringe at this level of distortion?

The answer is not what you might believe at first sight. We have become so used to thinking of distortion specifications in terms of figures like ‘0.001% THD’ that a result like ‘2% THD’ looks horrendous. Yet it wasn’t always so.

In the infancy of hi-fi it was not unusual for the valve (tube) amplifiers of the day to produce harmonic distortion figures of 1% or more. Yet some of the classic valve amplifier designs are now highly regarded by modern listeners.

How come?

One statistic that is rarely pointed out is that 1% of Harmonic Distortion, providing that it is JUST Harmonic Distortion and nothing else, is inaudible. You cannot detect it - period! In that case why do amplifier designers go to such great lengths to reduce distortion to miniscule fractions of a percentage?

The answer is two-fold. One is an obvious marketing ploy - specmanship. The other reason is that not all distortion is created equal!

In fact the majority of distortion that we hear from an amplifier is non-harmonically related. And this type of distortion is readily detectable down to fractions of a percentage. It is also apparent that non-harmonically related distortion is very difficult to measure accurately in the way it relates to our hearing perception. And would you believe that solid state amplifiers tend to produce higher levels of non-harmonic distortion than their valve counterparts?

This is by-the-by. What we are concerned with here is speaker distortion. And the distortion measured from loudspeaker drive units is largely harmonically related. Which is why we can put up with high measured levels. We can also add that our perception of harmonic distortion is frequency dependant.

What that means is that, at low frequencies, the measured distortion figure can be as high as 5% and still be innocuous. At midrange frequencies, particularly in the midrange to treble crossover, our acuity is greatest. As you might expect that is where distortion ought to be the lowest.

So far we have only talked about the drive units and their related distortion. What about the rest of the speaker?

Other than the drive units the other sound producing part of the speaker is the cabinet. We’ve touched on this elsewhere but the contribution of the cabinet to the sound you hear is much greater than most pundits would have you believe.

Why? Because the cabinet output is usually non-harmonically related. Our research has shown that a number of factors influence the way the materials in a cabinet behave and whether they are under the influence of the drive units or not. We have found that most of the materials used in modern speaker cabinets generate sonic patterns which are not in accordance with the music being played. As such this output is the sonic equivalent of a sore thumb!

Our research also shows that these relatively modern materials produce the majority of their output in the midrange - exactly where you don’t want it to be, because in this frequency range it is disturbingly obvious.

So, when we were formulating the construction of EBACOUSTICS cabinets we deliberately chose materials which produced the majority of their output in the low frequency area. In this range it is much more difficult to detect the ’sound’ of the cabinet panels. So you hear more of the music, and less of the loudspeaker!

Do yourself a favour and listen to EBACOUSTICS speakers in the comfort of your own home. Then you’ll hear the evidence for yourself.