I like curiosities!

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It could be interesting to hear from unbiased experienced peoples on this forum about speakers we don't have a chance to hear because of their rareness or uniqueness, or their prize! (not rich enough to order a pair just for fun!)

...mmmhhh I should go to audio hi-fi shows more often!

I'm curious to hear about: Manger tweeter : http://www.manger-msw.com/en/produkte/index.html . Ribbon?, planar? piezo?(no of course!) ionic? Heil motion transformer derivation type? It is bizarre at least!

Fertin woofers with electro magnets, like the old times!: http://perso.wanadoo.fr/hpfertin/ ...maybe the best thing if you have AC outlet at the back of your speaker box! ant it is tunable speaker...

And the Aurasound Pro sub-woofer (NRT18) that's supposed to'eat' any other sub for breakfast : http://www.aurasound.com/

And the Lowther 8" series (hyper-efficient hp) : http://www.lowtherloudspeakers.com/homeindex.html

Those Lowther have unconditionnal fan club base who swear by it's midrange and quickness... that can be used with SET tube amps.

And the Babb speaker!!!: http://www.babbspeakers.com/loreleihome.htm

Lots of wonders and nice reading.

Well theese are something to discover!

[barefoot]

I'm curious to hear about: Manger tweeter :. Ribbon?, planar? piezo?(no of course!) ionic? Heil motion transformer derivation type? It is bizarre at least!
This is a flat version of a "bending wave" speaker. Here's an interesting DIY article showing a picture of the original Ohm Acoustics version https://athena.safe-order.net/decware/radial.htm And here's another company that makes a more traditional version http://www.german-physiks.com/NewFiles/BodyDDD.html It's a fun concept, but it can't compare to good dynamic piston type drivers.

Fertin woofers with electro magnets, like the old times!: ...maybe the best thing if you have AC outlet at the back of your speaker box! ant it is tunable speaker...
Unfortunately I don't read or speak French, but numbers are thankfully universal. Looking at the specs my question is... why? These flux densities and power sensitivities can also be achieved with permanent magnets. And it's difficult to imagine that electromagnets would be cheaper or more compact. So, why? Tunability?

And the Aurasound Pro sub-woofer (NRT18) that's supposed to'eat' any other sub for breakfast
Yeah, these are truly great drivers. I've built a few subs using this one and also the "Leviathan" variation sold by North Creek. Giant, yet very low distortion bass. Incredible. The auto sound versions are also great.

And the Lowther 8" series (hyper-efficient hp) : Those Lowther have unconditionnal fan club base who swear by it's midrange and quickness... that can be used with SET tube amps.
Yeah, Lowther drivers have gained bit of a cult following with the Horn Speaker/Single Ended Tube Amp crowd. Fun. And some of the horns look cool as hell, but the specs don't support the wild claims. So, the profits of this superstition say "don't trust the numbers, trust your ears!" Well, I'm not superstitious.

And the Babb speaker!!!:
Never heard of these. I guess the spaced coil and the heat dissipation plates are their unique claims?

In all my investigations the traditional arrangement of bandwidth limited moving coil loudspeakers still offers the highest and most accurate performance - winning over full range dynamics, electrostatics, planers, ribbons, etc. Maybe some new technology will come along soon to replace it, but so far it's still proving to be the best. The Aura sub is just an extreme version of the traditional design.

Thanks for the interesting topic!:D

Thomas

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And it's difficult to imagine that electromagnets would be cheaper or more compact. So, why? Tunability?

Yes tunable. You can change the power(voltage provided by the power supply) applied to the electro magnet to change the damping force to it so you change the parameters.

The beauty of this principle(tunability apart) is that you'll alway get 100% of the claimed gauss specs even after 20 years of play. Heat and vibrations deteriorate (slowly but shurely) the effectiveness of the "permanenet" magnet, then it's efficiency and magnetic force.(some claim that you can end up to 50% of the original strengh) This doesn't applies to the electro-magnet. I've read in some serious paper that each time you knock a permanent magnet, it looses 2% of it strengh. So it is like a deducting income table(xcuse my english)(!!!) it goes like 2% of 100%=98%, and 2% of 98%= 96,04% and so on. Finally the permanent magnet behaves like the brain!:lol: (brain looses it's acuity each time it is knocked. This should come from a WWF table!!!)

D-Box uses theese speakers for subs and from the reviews, this is another nice sub.

http://www.d-box.com/engmammouthart.html

And the Aurasound are used by a PA company for subs and the guy told me that in the 30Hz range, one 18 inches worth at least two 18 JBL's (new neodimium) or anything like!.

From what claim German Physiks, their flagship (The Gaudi)is "supposed" to compare to a PA (witch I tend to syay that they mean small PA! )

http://www.german-physiks.com/NewFiles1/Speaker.html

[barefoot]

Well, I can't say I'm any closer to being convinced of the benefits of an electromagnet. I would be concerned about several things:

Ripple from the magnet's power supply, voice coil flux modulation due to a possible inability of the electromagnet to saturate the gap, heat generated by the electromagnet causing even higher than normal distortion, power consumption, inconvenience, ...etc.

I'm also skeptical about those demagnetization numbers you sited for permanent magnets. Even assuming they're true, I would bet it's still more cost effective to just build a traditional design with an oversized magnet to compensate for thermal and vibrational deterioration.

Thomas

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About electro stuff...

Talking about power supply: theese speaker power supplies were designed in the 30/40's You can't compare these years to today! You know that you can make some quite clean power supplies now! (about 18 volts, 5 amps, this is easy!) So, forget about ripple!

Anyway...

For me this is a curious return to the roots! But still a curiosity. I don't think that I can judge if they came around the "old" problems that plagued those drivers at that time, but I can positively think that theese guys found something to come around. (just read the article about the Mamooth sub!)
It is always interesting that some peoples come back to the old drawing boards just to see if they could better some designs. I wouldn't throw right away theese initiatives.

IMHO

Anyway I'm happy that there is (are?) someone that read my posts or questions about speakers, because for me speakers are the ultimate link to be bettered to render music!(I'm a pro musician for 30 years!) I know the music, I know what lies or doesn't (from a sound , performance and emotion point of view)

For me transducers are a fascination

And.. this is not a religion, just science!