Speaker Technology over the last 10 years

04-05-09: Mrtennis
as to faults of cone design, they include the following:

cabinet colorations, lack of driver coherence, stridency of many metal-based tweeters, and crossing over dissimilar drivers

Those are not faults of cone design, but of enclosure design, driver selection, and driver integration. All can be corrected and often are. To wit:

Cabinet colorations: Increasing numbers of dynamic speakers have curved panels, increased amounts of bracing, and materials other than MDF. The thin-ply birch stock (also used for piano pin blocks) are seeing increasing use. Brands that use this very inert material include Lominchay, Nuforce, and Magico.

Lack of driver coherence: Pick drivers with similar rise times and physically align them on the baffle.

Stridency of many metal-based tweeters: 20 years ago, maybe. There are plenty of good metal-dome tweeters. The titanium tweeters in Mirage speakers have cloth surrounds, damping out all the ringing and leaving superior speed and linearity without diaphragm breakup. Tweeter materials fall in and out of fashion and have little to do with actual performance IME.

Crossing over dissimilar drivers: Use more similar drivers (duh). More and more drivers are made in families. Not only does Mirage use a titanium tweeter, all their cone-based midranges and woofers have vapor-deposited titanium to match the sonic signature.

These are all straw man arguments against cones. Some of the best speakers in the world are cones, including the best from Wilson, Magico, YG, Avalon, Vandersteen, Thiel, JM Labs ......., none of which exhibit the "faults of cone design" you mentioned.

Alright, enough Mr.T bashing. One of the most appealing aspects of large panels is the oversized soundstage—great on large scale recordings, and although unrealistic, quite attractive on intimate small scale recordings, such as, solo guitar, lute, violin. If one is completely sold on that scale of soundstage, box speakers can be underwhelming no matter how good they are in other respects. As an analogy, years ago when Fujichrome was first introduced in the US, many people went gaga over it. It wasn't because Fuji was better from a fidelity standpoint, it wasn't by a long shot. Ektachrome had far more realistic color rendition. It was because the high color saturation was so appealing. Could it be said that panels have a "higher soundstage saturation?"

It's too bad this thread has taken a detour from new technology. Has there really been anything revolutionary or only incremental improvements?

The only newer things I'm aware of are the MBL radialstrahler driver, Manger driver, the Impact airfoil, all bending wave drivers of some sort. Haven't heard any of these. What is almost universal is that new or exotic technologies usually do high and sometimes mid frequencies well, but low frequencies still need to be handled by conventional cone drivers. The exception to this is the Eminent Technology's rotary woofer. Quite an ingenious approach to infrasonic sound production.

Nothing has advanced, just new twists on old designs... Some materials have become slightly cheaper and more relevant again, but only real "Advance" would be in Capacitors for crossovers, some extremely different and better sounding caps are developed today, but even then most of the speaker companies unless paying mucho dollars don't use them anyway.

04-13-09: Ojgalli
Alright, enough Mr.T bashing.

I wasn't bashing Mr. T. I was using his outdated indictments of dynamic speaker systems to illustrate the very topic of this thread. More cone-based speakers at more price points have reduced or eliminated their glaring disadvantages in the past 10 years.

In an earlier post, I mentioned several developments of the past few years that have catapaulted speaker performance over what was affordably available 10 years ago. I mentioned the API/Mirage developments of the Omniguide and their elliptical rib surround, which totally changes the rules on diaphragm diameter vs. cabinet size, bass extension, and clarity. I mentioned increasing use of neodymium magnets and beryllium tweeters. To that I could add that offshoring manufacturing to China has made intricately built enclosures affordable. Basically China has freed us from the box speaker. More and more speakers at affordable prices have elliptical shapes, curved sides, curved tops, and the attendant decrease in cabinet resonances and standing waves. More are getting away from MDF, using polymers, extruded aluminum columns, multi-ply birch from Europe (the stock used for piano pinblocks), and staved construction a la Sonus Faber and Usher.

Drivers haven't stood still. Witness the emergence of the ring radiator tweeter, which has found a home in many upscale loudspeakers from Sonus Faber, Magico, and AV123, and the ring ribbon as used by Adagio and Genesis among others.

These advances have made their way into entry-level products. Take a look at the averaged anechoic response curve of the $449/pair PSB Image B25 stand-mounted speaker. It is +/- 3dB from 50 to 20KHz, and is about +0, -2dB from 300 to 8 KHz where most of the action is. This level of linearity at this price point IS revolutionary.

There's been a resurgence in open-baffle designs.

Earl Geddes has identified and fixed a major source of horn coloration with his open-cell foam filled oblate spheroidal wave guides.

Tom Danley invented the unity summation aperture (a multi-way point source horn) and tapped horn for bass. He's produced compact bass horns that get a lot of the horn size from the environment.

DSP and digital amplification makes it easier to realize multi-amplification in high output active designs.

There are newer drivers which are linear over higher excursion (for more output, or a MT array with the same output as an MTM but better polar response).

There are newer drivers with less distortion and stored energy, but this is a minor change when you have good polar response and a correctly executed cross-over.

There are more small makers which essentially charge you for parts plus a furniture maker's time. You can get much more attractive veneers and solid hardwood pannels without spending five figures.

OTOH, if you buy a generic speaker with generic drivers it's unlikely to be appreciably better than an older speaker. It'll just cost more due to inflation.