... but I can tell you that we did the dip on purpose. Would have been easy to make it flat, but my ear would bleed during the listening test.
Adding an intentional dip is all very well and good, but from a philosophical point of view it simply appears that you have added a dip in the response to suit the recordings that you like to listen to.
The underlying assumption of that approach is that we also like to hear those recordings presented the same way. Why not include that type of dip in the amplifier as well? That would create quite a stir, but loudspeaker
voicing can be done in such a way that anything appears to be able to be justified on the basis that it somehow sounds
better.
If I have more time, I'll put together a little paper about the dip. It's a combination of all sorts of things coming together.
Please find the time if you can, as it would be a worthwhile and fascinating paper.
I always have this conflict within me.....my engineering brain wants to make it flat, but my ears and heart tends to leave a small valley for better sounding results.
"Better sounding results" is not going to be a particularly good way of approaching the problem if the result is wrong, with respect to
accurate reproduction of what the recording artist intended. The baked-in dip is the antithesis of modern loudspeaker design, based on the available evidence it would seem. Of course, incorporating a dip can and does provide a sonic signature that delineates a product from others in the market. Again, why not do this to an amplifier to produce "better sounding results"?
We are at the end of the "Food" chain and we have to make sure, the result is enjoyable. I have no idea if certain voices have been recorded in a way that gives me pain.....I can just try to find a compromise that makes the maximum available recordings as enjoyable as possible. I don't want to make speakers that only work on just one perfect track
Sure, being at the end of the food chain means that the choice is affected by the listening room. However, a loudspeaker with a flat axial response characteristic can be enjoyable too, and probably on an even wider range of material than a loudspeaker that has been adjusted 'to taste'.
Where does one draw the line at applying a graphic equaliser to the loudspeaker's transfer function? The inclusion of a dip seems to be quite unnecessary and counterproductive in an overall sense. And with any baked-in dip, we as consumers of the end product generally have no knowledge at all of what source material, amplification, and listening environment were used by the designer. That's a lot of unknown variables, whose effects on the chosen 'voicing' are therefore unknown.
Another loudspeaker designer's take on building-in equalisation to a loudspeaker's transfer function is somewhat at odds with the philosophy of introducing dips. For example, Shorter (1958), who was with the British Broadcasting Corporation at the time, suggests that broad dips/changes in the frequency response can be regarded as defects (i.e., distortion). For example:
- "Even a shelving characteristic ... can give the effect of a 'disembodied' high-frequency output".
- "Experience with loudspeakers of known characteristics, supplemented by experiments on raising or lowering the response in specific regions by means of band-pass or band-stop circuits, enables the subjective effect of an excess or deficiency to be predicted. If a progressive decline in response with increasing frequency is followed by an increase, the upper frequency range will be heard to stand out in unnatural relief, even though the response may nowhere rise above the mid-band level. It should be noted that this form of frequency characteristic modifies the spectrum of the reproduced sound in a way not experienced when listening to natural sounds." (emphasis added).
- "The second observation concerns the critical nature of the frequency band in the region 2-4 kc/s, the level of which, relative to the remainder of the spectrum, has a pronounced effect upon the apparent auditory perspective. Deficiency in this band gives a distant impression; slight excess gives a forward quality, sometimes referred to as 'presence'. The tonal quality associated with extreme deficiency or excess in this region ranges from hollow, or distant, to hard or metallic.* This complete gamut of effects can often be passed through with a change in level of plus or minus a few decibels in the band concerned." (emphasis added)
* "Such expressions as these may seem out of place in a technical context. They are, however, typical of the terms in which the end product of a sound-reproduction system is described by the observer, and when employed by individuals known to be capable of consistent judgment must be treated with respect."
Shorter, D. E. L. (1958).
A survey of performance criteria and design considerations for high-quality monitoring loudspeakers. The Institution of Electrical Engineers, Radio and Telecommunications Section, Paper No. 2604.