Intro/ribbon drivers

[thetubeguy1954]

Welcome to the forum. Very nice first post .

I think both they myth and fact are true . It is true that these drivers have large surface area and can cool off that way. But it is also true that they don't really like to get hot as that can deform the substrate and or delaminate it. The company we were working with really sweat this as they had drivers destroyed this way and they were always looking for ways to make them better.

Amir talk to Bo Bengtsson at Transmission Audio. He responds quickly and will take the time to answer your questions. IIRC Bo believe's the only ribbon drivers that will be destroyed by large quantities of clean & undistorted power, are ribbons that's are not properly constructed from the beginning. As Bo states "The best ribbon would be a transformerless, purely resistive, (coil-less and carrier-less), pure metal film ribbon of open dipole-type, suspended at its ends only, wide enough to give a good coupling down to the lower frequencies. This is exactly what the Transmission Audio Ultra Propulsion© technology is all about."

The problem Amir is most of what passes as being a "ribbon" driver today is actually a form of Planar Magnetic Transducer. Perhaps the company you were working with should contact Bo? Transmisson Audio offeres a variety of services: http://www.transmissionaudio.com/servicesandportfolio.html as well as being able to provide the company you were working for an incredible variety of ribbon speakers to choose from, should they only be looking for one or a few pairs! With that I should probably end this by stating I am not affiliated with Transmission Audio in any way and say Good-bye...

[FrantzM]

Tom

Valid points but it remains that any conductor can be destroyed by heat and in the case of ribbon it can be rather low... In ribbon the main problem remains that of the substrate usually a plastic (Mylar, Kapton, etc) .. when submitted to high currents the substate, the film itself can deform or be damaged permanently. True the large area allows cooling of the wires but the sibsrte itself as a (rather) low melting temperature, compared to that the metal reach under sustained high current... but indeed I have been surprised to see how much power some ribbons and quasi-ribbons can take at times... (Apogee and Magnepan)

[thetubeguy1954]

Tom

Valid points but it remains that any conductor can be destroyed by heat and in the case of ribbon it can be rather low... In ribbon the main problem remains that of the substrate usually a plastic (Mylar, Kapton, etc) .. when submitted to high currents the substate, the film itself can deform or be damaged permanently. True the large area allows cooling of the wires but the sibsrte itself as a (rather) low melting temperature, compared to that the metal reach under sustained high current... but indeed I have been surprised to see how much power some ribbons and quasi-ribbons can take at times... (Apogee and Magnepan)

Frantz while I agree wholeheartedly that any conductor ---**even a ribbon}--- can be destroyed by heat, but I disagree that in the case of ribbon it can be rather low. The problem once again is too many "supposed" ribbons aren't ribbons at all! If the "ribbon" has a substrate of plastic (Mylar, Kapton, etc) I say that is actually a form of Planar Magnetic Transducer and not a ribbon! I agree with Bo Bengtsson at Transmission Audio i.e., a ribbon is a transformerless, purely resistive, (coil-less and carrier-less), pure metal film ---{no substrate}--- that's suspended at its ends only!

Of course you're free to have a completely different interpretation of what a ribbon truly is...

[DonH50]

Hmmm... IME, the problem with burning up ribbons was because the (metal) film was so thin and narrow the tweeters would fry (separate, actually) over time. I suspect this issue was exacerbated by the low (if resistive) impedance of the ribbon, which may lead to amps clipping and pushing more HF energy into them than they were designed to take. Almost every ribbon and quasi-ribbon maker I have known (Magnepan, Infinity, Appogee, Carver) seemed to have struggled with this now and then. While I seem to recollect one owner claiming to have damaged a bass panel, I do not recall seeing any bass/mid ribbon panel issues.

Quasi-ribbon drivers utilize metal film on a plastic'ish carrier (substrate). I have read a couple of pro/con articles and don't know enough to say which is better. The con folk say the substrate adds mass and is a poor conductor of heat, hurting the sound and reliability. The pro folk claim the substrate helps protect the metal film and dampens ringing. I have no idea which is true and/or to what extent. Of course, having had Maggies for ages, the delamination problem can be a bitter pill to swallow after years of use. I wonder if their new QR designs eliminate, or at least reduce, that issue (?)

[A.wayne]

Amir talk to Bo Bengtsson at Transmission Audio. He responds quickly and will take the time to answer your questions. IIRC Bo believe's the only ribbon drivers that will be destroyed by large quantities of clean & undistorted power, are ribbons that's are not properly constructed from the beginning. As Bo states "The best ribbon would be a transformerless, purely resistive, (coil-less and carrier-less), pure metal film ribbon of open dipole-type, suspended at its ends only, wide enough to give a good coupling down to the lower frequencies. This is exactly what the Transmission Audio Ultra Propulsion© technology is all about."

The problem Amir is most of what passes as being a "ribbon" driver today is actually a form of Planar Magnetic Transducer. Perhaps the company you were working with should contact Bo? Transmisson Audio offeres a variety of services: http://www.transmissionaudio.com/servicesandportfolio.html as well as being able to provide the company you were working for an incredible variety of ribbon speakers to choose from, should they only be looking for one or a few pairs! With that I should probably end this by stating I am not affiliated with Transmission Audio in any way and say Good-bye...

Agree,
Most call planar drivers, ribbons and they are not, very difficult to burn a pure ribbon transducer, with the right diaphragm for the job ...

regards,

[Justus]

Frantz while I agree wholeheartedly that any conductor ---**even a ribbon}--- can be destroyed by heat, but I disagree that in the case of ribbon it can be rather low. The problem once again is too many "supposed" ribbons aren't ribbons at all! If the "ribbon" has a substrate of plastic (Mylar, Kapton, etc) I say that is actually a form of Planar Magnetic Transducer and not a ribbon! I agree with Bo Bengtsson at Transmission Audio i.e., a ribbon is a transformerless, purely resistive, (coil-less and carrier-less), pure metal film ---{no substrate}--- that's suspended at its ends only!

Of course you're free to have a completely different interpretation of what a ribbon truly is...

Hi there from another ribbon enthousiast (if fact..I wrote the book "Ribbon Loudspeakers").
I fully agree with your notion that the "ribbon" term should generally be used to exclusively refer to an aluminum strip-like conductor suspended at 2 ends with very low resonance frequency.
Yet, outliers do exist still worthy of calling ribbons.
Many examples do have xformers when physically small (Raven, etc), or have support at the sides (Magnepan). Others do use a substrate (Apogee). Etc.
So, we should leave some leeway for practicallity.

Planar-magnetic is a different beast altogether, indeed clamped at sides, but more importantly (typically) with magnets in front and behind the membrane, with its own pros and cons.
For one, they can be easily designed to play lower then most practical true ribbons...(think Bohlender)

Power-wise generalizations are tricky (think Stage Accompany!), it depends...but a high-order XO is recommended as usual