IB Cone materials.

[chrisbee]

Perhaps this would be a good point to raise the question of the various cone materials used in our IB driver choices.

Is the difference noticeable between reinforced paper pulp, spun aluminium and poly plastics?

Is it really worth choosing one material over another when deciding between driver options?

Given the usual powerband of an IB driver can we even distinguish one cone material from another in practice?

Has anyone changed from one material to another and can contribute with some direct observations on sound quality changes?

[ThomasW]

Since we recommend multiple drivers, we're less concerned about cone breakup than those using a single driver mounted in a 'box'

Were someone so motivated they could take representative samples and look at the first cone breakup mode. Sometimes one can see this as a bobble or glitch in the impedance plot. The higher in frequency the breakup mode the stiffer the cone. And the stiffer the cone the better.

As a rule of thumb metal and exotic plastics (kevlar, carbon fiber) are the stiffest. Reinforced paper is the next followed by paper and poly.

[chrisbee]

Thankyou, Thomas.

Can we be certain that cone stiffness is directly related to multidriver IB sound quality?

My fuzzy logic suggests a steeper transient and lower distortion from a stiff cone but what about damping of these higher frequency breakup modes?

Are we protected from these by the typical low pass filter applied to LFE in an average HT system?

[ThomasW]

Cone breakup modes occur at higher frequencies. Depending on the passband those breakup modes impact the cone's performance at lower frequencies.

Between any two given cone materials the stiffer material will be more pistonic (aka linear). And linear performance equals greater accuracy.

IMO it's better to leave the damping to the motor/suspension instead of trying to rely on the cone material.

When targeting fullrange reproduction, novice builders, those fixated on first order filters, or of 'fewer XO components the better' philosophy tend to prefer paper or poly cones, since they're inherently more 'forgiving'. Personally that's not a school of thought to which I subscribe, but that's a topic for a different forum.

[chrisbee]

Thanks, Thomas.