Speaker 101 - tweeter and cone materials


Ceramic, silk, paper, polyproplylene, polymer composite, aluminum, magnesium, kevlar and many more.
Each material must have its own strength, weakness and sound. Can you tell me what they are? What do you prefer for your taste of music?
odnok123
Well, let's be real basic - no offense. When crossing a woofer to a tweeter, a crossover is used that filters out the lows going to the tweeter, and the highs going to the woofer. Metal woofers (and all woofers) have cone break-ups at frequencies higher than they are designed to produce. Since metal cones sound particularly harsh when fed any higher frequencies near their cone break-up frequency you want to make particularly sure that they get very little input above their crossover frequency. Now, you might say how does that happen if you have a crossover. Well, a crossover is not an absolute. It has a roll-off at the crossover frequency. Let's say a woofer cone breaks up at 10k. With a 1st order rolloff, and a crossover frequency of 2.5k, the woofer is only 12db down at 10k. This will be heard easily. Now, go to a 4th order rolloff, and the woofer is 48k down at 10k. This will likely not be heard as much.

Steep slopes are created by higher order electrical crossovers. With metal cones, you'd probably want at least a 4th order "acoustical" roll-off. This can generally only be created by higher order "electrical" crossovers. In general, the higher order the crossover, the more complex the crossover becomes in terms of component count. (This is not absolute, just a generalization. Depends on how many "shaping" filters are used.) The result is a rapid roll-off of higher frequencies in the case of a woofer.

With metal cones it is more imperative because they emit some real nasty break-up noise if they receive any signal at their cone break-up frequency. In many cases, the designer will also incorporate extra "filters" to eliminate specific frequency ranges above the crossover frequency at about the cone break-up frequency. These extra filters also add to the component count. Crossover design is a complex science/art. Folks will say there are simple textbook formulas to calculate these things. They are wrong in terms of actual application and it becomes more so when you factor in things like woofer breakup and tweeter resonances, not to mention things like baffle step for small boxes designed to be used well away from room boundaries.

Joseph Audio speakers are a good example of metal cones that can sound good although again it's a matter of taste. His designs use particularly steep filters. Some designers and listeners are of the opinion that such complexity detracts from the sound. In the end, it's a matter of personal preference.
Javachip, Gmueller, Thank you for your inputs.

If there are more sites I can learn from, please let me know.
I like the materials but mostly the engineering to the Seas'. They seem to get the best balance, fluidness and rigitity, resulting in most musical.
There are good and bad sounding speakers using all sorts of cone material.
More important is cone suspension/surrounds.
Most modern speakers use quite thick rubber surrounds which allows for long cone excursion, which allows them to produce lots of low bass.Unfortunately it also produces a slow smeared sort of sound.This is why most modern mainstream speakers sound so bad and why so many hardenned audiophiles end up using things like Fostex,Lowther and Zu speakers that have cloth surrounds and short excursions.
Anyone who dosn't believe that modern cone surrounds are wrong needs to listen to a pair of old Goodmans Axiom 80s that have no surrounds!

JT