Cone materials

[JRT]

Re: Cone materials

Realistically, which cone materials are best for sound quality? I have always thought that it was paper, having better dampening, low distortion, and a flat response. However, someone has caused me to doubt this. I understand that this is only one of the many variable when considering sound reproduction, but if you had identical drivers, except for the cone materials, which would create better acoustics? This inquiry is not limited to an "the" best material, just wondering which are some (3-5) of the best to consider in a system and why?

Beryllium is a very good diaphram material.

Acoustic Properties of Beryllium

Voice Coil January, 2004 reprint

Voice Coil May, 2003 reprint

Voice Coil September, 2001 reprint

A midrange example, Usher 0541A (select "Frequency Response & Impedance" and "Distortion" to see those graphs in the Adobe Flash app, not sure what level was used in measuring nonlinear distortion):
http://www.usheraudio.com/driver-0541A.html






.

[romanbednarek]

Re: Cone materials

Realistically, which cone materials are best for sound quality? I have always thought that it was paper, having better dampening, low distortion, and a flat response. However, someone has caused me to doubt this. I understand that this is only one of the many variable when considering sound reproduction, but if you had identical drivers, except for the cone materials, which would create better acoustics? This inquiry is not limited to an "the" best material, just wondering which are some (3-5) of the best to consider in a system and why?

Regarding the concept of drivers using the same motor but different cones I have a few examples at the links below (but keep in mind that I put these pages together quite some time ago so my recent responses may be more accurate regarding the explanations).

CA18 vs L18

http://www.rjbaudio.com/Audiofiles/c...materials.html

XT18 vs XG18

http://www.rjbaudio.com/Audiofiles/V...20vs%20XG.html

Just keep in mind that there really isn't a clear cut answer to your question because a lot depends on the application of the driver as well as the preference of the listener.

[3way]

Re: Cone materials

Modern treated paper cones like Scan Speak slit paper Revelator with carbon fibers sound good to my ears. I have a pair of B&W Kevlar 5" midranges with great detail but fatiging even with a notch filter, just like all my metal cone designs. Superior sounding woven fiber cones will likely require a multi-million dollar machine to manufacture Kevlar synthetic aramid fibre with a variable weave to be stiffer near the voice coil and more absorbing near the surround. I'm watching for new dampening technology on kevlar and metal cones.

http://www.bowers-wilkins.com/displa...788&artid=1417

[romanbednarek]

Re: Cone materials

Modern treated paper cones like Scan Speak slit paper Revelator with carbon fibers sound good to my ears. I have a pair of B&W Kevlar 5" midranges with great detail but fatiging even with a notch filter, just like all my metal cone designs. Superior sounding woven fiber cones will likely require a multi-million dollar machine to manufacture Kevlar synthetic aramid fibre with a variable weave to be stiffer near the voice coil and more absorbing near the surround. I'm watching for new dampening technology on kevlar and metal cones.

http://www.bowers-wilkins.com/displa...788&artid=1417

My friend has a pair of speakers with those Kevlar drivers in them but they use them in an interesting way. Those Kevlar midranges do NOT have any surrounds and rely on the flexing of the cone which allows them to have better off axis performance higher in frequency because the higher frequencies only come from the center of the cone (dispersion is good because when off axis the distance between the far side of the radiating part of the cone and the near side is shorter meaning that the wavelengths were the two sound sources will be 180 degrees out of phase and cancel will be shorter). This is quite the opposite of a metal cone which doesn't flex at all and its off axis roll off occurs at the lowest possible frequency and has a very abrupt transition from pistonic behavior, but some people claim that true pistonic behavior is best even if you have to cross lower.

Back to the B&W Kevlar cone midrange... they still have a nasty high Q resonance peak and I've always felt that B&W used too high of a crossover frequency with their designs using this midrange (at least with the B&W Nautilus 802).

[curt_c]

Re: Cone materials

Non-linear distortion is best observed by looking at harmonic distortion measurements but extensive knowledge of motor designs as well as how the cone might react to a certain motor (for example metal cones "amplifying" the distortion when it falls on the resonant frequencies) can help you predict which motor designs might have advantages. Some motors are better at staying linear over a wider range of power levels (greater excursion in particular). I won't go any further than that because I don't have enough experience on this topic.

So far, great post guys. It seems that poly and paper cones have the lead!

[Guest]

Re: Cone materials

Which materials were these cones made of?

[tpremo55]

Re: Cone materials

Which materials were these cones made of?

I'm going to guess:

Titanium (like the TB 1337s in the Statements)
- and -
Ceramic (like the Accutons in the Uber-Exclamations)

..but just a guess...:D

[curt_c]

Re: Cone materials

I'm going to guess:

Titanium (like the TB 1337s in the Statements)
- and -
Ceramic (like the Accutons in the Uber-Exclamations)

..but just a guess...:D

[Guest]

Re: Cone materials

Look forward to hearing, or seeing, how they turn out.