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How much impact does driver material actually make?

Frank Dernie

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Beryllium sounds different to me than other tweeter , i believe 100% that materials do make a big difference
Most tweeters have breakup, ie resonant modes, in the audible range. This is ameliorated by applying a damping goo, but still leads to a potentially uneven response. They will also only be radiating from a ring close to the voice coil at the highest frequencies since the rest of the dome will be decoupled from the motor system by the breakup.
Metal domes are mainly not doing this, though the less stiff ones like titanium may well have a rising response or even a peak in the audible range too.
Of all tweeter materials Beryllium is potentially the one adding the least colouration to the tweeter output in the audible range.
The dome/cone material is by no means the only thing influencing the SQ of a driver though.
 

brimble

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My old Monitor Audio speakers have dome tweeters and kevlar midrange drivers.

I don't have much opinion about the sound (beyond the fact that they were great value for money because I got them very cheap), but the kevlar is orange and looks great!
 

Beave

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As evidenced by the various responses above, the obvious answer is that the material makes a difference how a driver behaves, but not whether that behaviour is good or bad.

I’ve owned and built speakers with drivers ranging from paper, to magnesium, to papyrus, to aluminium ribbons, to electrostatically charged plastic, to ceramic, to diamond, to the intestines of a ritually slaughtered goat.

In spite of their claims at the time, and my varying levels of enthusiasm, none are or were intrinsically better than another.

Berylium is the flavour of the month for tweeters, for example. Yet SB Acoustics lowly SB26AC measures better than their lofty SB29 Be.

Measures better in what? Frequency response on axis? Off axis? Sensitivity? Power handling? Resonance frequency?

KEF and Genelec aside, none of the top-rated speakers here have exotic or unusual drivers. The Revel M106uses quite ordinary SB Acoustics drivers. But it uses them well. The Ascend Sierra has exotic drivers yet doesn’t use them well.

Which Ascend Sierra are you referring to that doesn't use 'exotic' drivers well? The Sierra 1 doesn't have exotic drivers, so that's not it. The Sierra 2 does use a ribbon tweeter, so maybe that's the one you're referring to?
 

carewser

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It seems to me that the only drivers we've decided aren't up to snuff in my nearly 40 years of being into this stuff are cone tweeters, it's been a long time since i've seen anyone use them

We've made improvements to speakers along the way though, even if their sonic improvements are dubious but result in greater durability like butyl rubber surrounds instead of foam and polypropylene/kevlar drivers in lieu of paper
 
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Harmonie

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My old Monitor Audio speakers have dome tweeters and kevlar midrange drivers.

I don't have much opinion about the sound (beyond the fact that they were great value for money because I got them very cheap), but the kevlar is orange and looks great!
If your drivers made of Kevlar are Orange, I would worry. These para-aramids are Yellow (bright Yellow) ;)
Anyhow, it wouldn't be the colour that will alter the sound. Maybe the resin or coating is Orange ?
 
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briskly

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Every time someone asks this, I think of another question: Can you hear the shape of a drum?
Is there actually any serious advantage to any of the more advanced materials for mid/bass drivers over simple doped paper? And for HF drivers, is there really much of a (dis)advantage for various metal designs or ribbons vs doped silk/fabric?
Besides the costs of the material and the required tooling?
-Most of these materials are dense and heavy, more so than paper and other "soft" materials in similar configurations. They are not made thin enough to retain reasonable efficiency for mid-high audio frequencies. Beryllium has a low density with high stiffness to weight, but this only makes for 1-1.5 dB of difference compared to aluminum.
-High material stiffness, such as corundum or diamond, is a result of the tight and uniformly bonded lattice of the material lacking internal friction. The stiffness and density tend to overwhelm the small losses intrinsic to the material. The defects in the structure of certain softer materials, such as magnesium, weaken the material but increase internal losses.
-Forms with great geometric stiffness constructed of materials with high modulus/weight ratio have less bandwidth than softer cones and reduced power response and less suited for wideband driver duty. Seen a different way, the flexure of the cone offsets the natural increase in directivity as wavelength decreases relative to radiator diameter.

Ribbon tweeters are made out of ordinary materials driven by the usual Lorentz force. The magnetic circuit arrangement lowers motor force BL²/Re compared to typical high-end Neo tweeters, but the mass is small for the surface area, keeping efficiency reasonably high. An advantage is the more uniform excitation of the membrane, suppressing resonant modes that might be obvious if locally driven by a former or coil. Usually, the available excursion is small, resulting in a disappointing non-linear response at the lower range of the driver and high cutoff frequencies.

The contribution of the membrane material and geometry are mainly in the linear parameters: the axial response and directivity. As for nonlinear parameters, the main contributors are motor force variations and inductance effects. These come from the loudspeaker motor; the membrane choice is less critical to nonlinearity.
Most loudspeakers operate each drive unit in a very limited frequency range, so the question of sound quality has more to do with the integration of the components into a whole unit.
 

Harmonie

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Every time someone asks this, I think of another question: Can you hear the shape of a drum?

Besides the costs of the material and the required tooling?

Most loudspeakers operate each drive unit in a very limited frequency range, so the question of sound quality has more to do with the integration of the components into a whole unit.

https://www.cabasse.com/en/cabasse_product/la-sphere/
 

MattHooper

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About tweeter material, just listen a cymbal sound track: you will immediately recognize the aluminium dome material.
You get some harmonics that you will never have with a silk dome tweeter.
But for other instruments a silk dome tweeter sound better.
How does sound a beryllium tweeter?

It's intuitive that a metal tweeter would reproduce the sound of metal better (e.g. cymbal). But that it's intuitive should make it suspect ;-)

I own a speaker that uses all metal drivers including tweeter and it is "very good" but not "great" with the sound of cymbals. Whereas another speaker I use sounds particularly great with drum cymbals - super clear and decidedly "metallic" for drum cymbals. It uses a soft dome tweeter.

So, I think it's mostly in the implementation/driver choice.
 

Harmonie

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It's intuitive that a metal tweeter would reproduce the sound of metal better (e.g. cymbal). But that it's intuitive should make it suspect ;-)

I own a speaker that uses all metal drivers including tweeter and it is "very good" but not "great" with the sound of cymbals. Whereas another speaker I use sounds particularly great with drum cymbals - super clear and decidedly "metallic" for drum cymbals. It uses a soft dome tweeter.

So, I think it's mostly in the implementation/driver choice.

Why would a metal tweeter would reproduce the sound of metal better ?
I mean is there a metal to metal relation ?

I'll stop here because I would have nasty ideas with silk tweeters, pulp, aramid, carbon woofers aso ...
 

Harmonie

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And you need horn speakers to reproduce horns, preferably made of brass, I would think. ;)

Not only brass :

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1606510653720.png


1606510675563.png
 

MattHooper

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Why would a metal tweeter would reproduce the sound of metal better ?
I mean is there a metal to metal relation ?

I'll stop here because I would have nasty ideas with silk tweeters, pulp, aramid, carbon woofers aso ...

For the same reason interconnect cables using silver wire sound "brighter" than copper.

;-)
 

carewser

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And you need horn speakers to reproduce horns, preferably made of brass, I would think. ;)

That's a great point, the best sounding piano concertos i've ever heard came out of ivory drivers
 
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Chromatischism

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For the same reason interconnect cables using silver wire sound "brighter" than copper.
Well, I suppose if you have a 200ft+ run from your amp to your speakers (why?), the tiny percentage less voltage drop would lead to a tiny increase in SPL for the silver wire. Which would only be noticeable if you swapped those out, quickly, for 200ft+ runs of copper or aluminum to compare. Otherwise of course it is complete bollocks :)
 

iMickey503

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This really has been a really fun thread. From http://www.roger-russell.com/sffun/sffun.htm To all the omnidrirectial speakers. And of course the Plasma tweeter. Something I would like to build one day.

It took about 2 days but worth it. Thank you everyone for the great posts. Had a great time looking up the pages and the info and of course the Nostalgia!

super great thread!
 

agiletiger

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What about a material’s effect if all things being equal? Let’s take the example of Revel Berylium tweeters vs their other tweeters? Are the Be tweeters measurably better? If so, is it worth the extra money for a Be model?
 
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