Originally posted by wadia-miester
Steve, question for you, how do you loose the inheirent intrinsic sound of a metal coned driver, to give a more natural feel ?, cabinet deisgn and 'x' over points can only do so much ?
metal drivers by the very nature are fast (low cone weight and improved acceleration properties, stiffer too), however I have always found them lacking in the mid band area, also they tend to be more 'colder and clinical', is the fact your using a multiple driver array helping this?
Good questions.
As long as a cone is acting as a piston its material doesn't effect the sound. As the frequency increases, the cone starts to enter break-up modes and in this region the material will have an effect. Contrary to some popular opinions, cone break-up is not something to be avoided at all costs but can provide excellent sound quality at higher frequencies, depending on the patterns of the break-up.
The frequency at which the break-up modes start depends on a number of parameters, including the diameter, thickness, hardness and contour of the cone. With the 2" cones used in the
Nonsuch 4, the break-up frequencies start well above the mid-range and into the higher treble region. The 'colder and clinical' sound that you refer to may apply to certain aluminium drivers and these are probably larger drivers where the cone break-up starts at lower frequencies.
The Bandor 2" drivers have a superb sound throughout the audible spectrum but I don't leave it at that. I coat the cones, back and front, with 3 coats of C37 lacquer. This is light enough not to effect the lower frequencies (particularly as it doesn't soak into the material) but above the break-up point it gives a sweeter high frequency, to my ears.
I use multiple small drivers instead of a single full-range driver as, everything else being equal, a 2" driver will have a superior high frequency response to a 5" driver. As a consequence of this, the units are also faster over their entire spectrum. Bass performance is related to the combined cone area of all the drivers. Four drivers also have increased power handling and efficiency compared with a single driver and have lower distortion. This gives a smoother sound.
A horn loudspeaker will also decrease distortion by its increased efficiency leading to less cone movement for a particular sound level. However, horns have other colourations and require a larger enclosure than I was prepared to design for.
I hope that this answers your questions. I'm always happy to explain my design thinking.
Only one thing really matters with speakers and that one thing can't be realized by reading about the theory alone.
I look forward to letting the speakers do the explaining to you, w-m and, of course to Merlin. They really are little charmers you know.