Lon...That would make a cool T-Shirt!
![Smiley Smiley](https://www.decware.com/yabbfiles/Templates/Forum/default/smiley.gif)
Will do, about getting to my ZMA 25th experience/in some more time... .
For the ZMA, Jeff intrigued me this past February with his musing's of offering the ZMA a little more speed. With Steve's discoveries and applying to the ZMA, I'm very pleased/speed & micro serving the macro music! My ZMA is seasoning in nicely.... .
I always knew it was not my Adagio's. I had in Tekton's and owned the DM947 Monoliths (all at the same time/rotating and listening with two other pair as well, mind you). They too, could be; not what I knew from my SE84CS delivering the music. For Steve to achieve the ZMA doing (UFO-25th SE) CS with power...is pretty damn remarkable.
Back to my Speaker's/Acoustic Zen Adagio's. The Tekton's & DM947's could not even come close to what my Adagio's achieve. The choice to have them cross cut at 4500Hz/single capped, instead of the 2500 tested and 3000 they were at....proved to be remarkable. These are fast woofer's and tweeter's.
Now! ...providing the true identity of my ZMA (because of the Mod's) & Steve's great Redbook source/ZDSD!
Mr. Lee's interview:
Tell me about your woofers. How does an underhung driver differ from a well-hung driver?
Underhung means that it has a very short voice coil in a large magnetic field gap. The drivers are top grade and so are the magnets. The voice coils are very narrow and always move in a linear manner within a magnetic field regardless of excursion. Additionally, a traditional long voice coil moving in a short magnetic gap presents a high variable impedance to the amplifier.
Can you break it down in some more detail?
With a short voice coil in a long magnetic gap, as the music signal flows through the voice coil, the coil and the cone moving together produce the sound wave. A long magnetic gap structure offers a much wider linear magnetic flux density, alternately pushing and pulling the short voice coil back and forth. Since the magnetic force on the coil is constant and completely symmetrical with the motion of the piston assembly, the result is a sound wave with extremely low distortion and coloration, allowing it to respond much faster to a transient signal and to stop faster after the drive signal has ceased.
Compare that with the large signal behavior of high-excursion overhung transducers. Because the coil extends beyond the control of the magnetic flux field, it causes very high harmonic and transient distortion that can reach 5 - 20% whereas the underhung driver maxes out at 1%. Because of the very complex magnetic structure and complications involved in voice coil placement and fabrication, the underhung voice coil is difficult and expensive to fabricate.
What are the speaker cones made of?
They use a ceramic-impregnated fabric in the center with ceramic coating on either side to form a sandwich. These drivers are custom built for Acoustic Zen to my specifications. The ceramic coating makes for a strong, dense, rigid surface area that will not break up nor produce a lot of ringing. The cone is very stiff and light and as a result, very fast. It responds immediately to a signal and returns to its original position very quickly. This minimizes frequency overhang, colorations and distortions.
Why a Neodymium magnet?
An underhung driver's voice coil requires an extremely strong magnetic field. If you are using traditional magnets, the size and weight of the motor would be excessive. Neodymium allows us to maximize magnetic coverage while controlling weight and size.
Why did you choose a ribbon tweeter and how does your circular design differ from other approaches?
I don't want to get too technical here. My circular ribbon tweeter design, unlike a traditional dome or cone tweeter, presents a purely resistive impedance that's completely linear in the audio range. It also has an essentially linear phase response, which contributes to an immediate and precise response to any transients in a complicated music signal. This dramatically reduces distortion and coloration.
I am using the thinnest diaphragm possible, a 0.01 millimeter Kapton diaphragm. That's just about weightless, with a 95% covered aluminum circle of conductors across the entire vibrating area positioned between super strong Neodymium magnets. Some people use metal ribbons which can result in very harsh HF response. Kapton is not only extremely light, it is also heat resistant, hence the thermal behavior of the voice coil will not translate into audible distortions. My tweeter's larger circular membrane not only provides much higher power handling and a wider frequency response, it also eliminates the offsets between horizontal and vertical dispersion that are common with narrow ribbons.