Originally Posted by MississippiMan
Ok Guys...here's the Skinny.
Audio Transducers such as the ones employed in RTD's system are decidedly simple things.
1. A 2.2 lb Alnico Ferrite Magnet Structure
2. A 1.5" Edge Wound Aluminum Vice Coil, which is both Frequency contoured, and heat dissipation assisted by the use of Ferro Fluid.
3. They are completely Sealed. Toss 'em in the Ocean for a year and no problem....they'll play just fine.
4. They are encased in a medium Density Composite Resin Plastic whose varying case thickness serves to both dampen and enhance Resonant Energy Transfer.
5. They come in 8 Ohm & 4 Ohm models. 200 Watts Max Output. 100 Watts Continuous.
6. Effective radial/hemispherical dispersion is 8' diameter from the epicenter of attachment.
Curtis Rolen introduced the first effective Transducer designed to resonate "solids" in 1958. In 1962, the basic design still in use today was developed. Improvements on materials, casing design, the use of high temperature Adhesives, and the drastic improvements in Amp / Signal source performance in relation to cost to performance ratios have only served to make what has always been a unique item all the more effective.
That it gets no press, let alone "A/V Enthusiast" respect is due to the fact that it's primary market has been Industrial / Military applications. Also Medical. Also Artistic. And a lot of other things that have nothing whatsoever to do with this Thread, .
What is certain is that it's the efficiency at what the Transducer can actually do when attached to a wide range of solid materials that still have a degree of resonant ability is what makes it something that few have ever experienced...considered possible...and fewer still can even comprehend let alone accept.
But for me...that's where all the fun comes in!
My roots lay in the design and construction of big...as in BIG
Sound Reinforcement Systems and PAs. Multiple Drivers in Multiple cabinets...the literal "Wall of Sound" concept. God knows I'm personally responsible for the destruction of many of my generation's Inner Ear Cilla.....and most obviously my own. For me, db Ruled.
In Red Top's system, the creation of multiple Driver arrays to accommodate effective dispersion of energy into the room was/is the primary goal. This can be compared to the example of the original "Wall of Sound" first advocated by Julian Hirsch in 1964....where 12 - 5" Full Range speakers were mounted in a specific pattern onto a 8' x 6' Wall enclosure. That led to the use of multiple 12" Extended Range Drivers, Exponential Horns, and Rear Loaded Bass Horn Cabinets to create a uniform "Blanket" of sound in huge areas.
But those same ideas and concepts still hold fast to deep truths. Distribute energy evenly and efficiently across a wide area and both accurate frequency production and dispersion will produce a physicality and presence that is at one more natural and uncolored than most directional speakers.
That's why the very most expensive conventional speakers more oft than not employ "many" drivers arrayed to distribute sound in such a manner as to make perceiving "directionality" almost impossible.
The Audio Transducer accomplishes this by imparting accurately produced frequencies (35 hz -18.5 khz on Drywall ... 20 hz-20 khz on Glass ) into a structural Solid via a focused point, and then the frequencies themselves radiate outward, with the highest Freq. waveforms localized at the center, Mid Range freq. traveling out until they reach their own specific point of resonant saturation, and the Bass freq. traveling out to the perimeters of a surface where their resonant energy can rake advantage of the increased mass of such broader, wider expanses.
Compare a 8' diameter resonating surface to a 8" diameter Full range speaker and what you have is simply a super-sized version...something akin to the huge Driver whimsically portrayed by Robert Zemeckis in "Back to the Future" and blasted by Marty McFly . A silly analogy, yes...but essentially a good visual representation..
So what about Red Top's system? Well if one Transducer can effectively energize up to 8' in diameter of Drywall or Wood...or Fiberglass...or anything resonant, the how well will am array of 2...or 4...or 8 such devices accomplish the same goal? (Shoot....I've used up to 16 Transducers on a 16' x 9' Screen Wall!")
The key to creating something "out of this World" lies in making a structural solid resonate accurately. Bending it's molecular structure to your collective will by imparting just enough energy over a broad enough area to cause it's molecules to do exactly what you want them to do.....aurally speaking.
I have a couple analogies I've used a few times over the last 33 years to help explain why using greater numbers of transducers is not a lesson in redundancy...but rather a cause to an effect.
Using a quantity of such Transducers is a way of doing what a Choir accomplishes. If you take a single vocalist and place him in a Sanctuary, even one with excellent acoustics, he'll be able to only go so far as to filling that space with energy (ie: volume...presence)
Now have 7 other Choir members join him. No one is trying to sung any louder than the solo member was singing, but collectively, the energy imparted into the room produces a significant increase in volume due to the saturation of frequencies into the air. Add another 49 Choir members and....
Now as far as energizing a structural solid.....
Suppose your driving a full sized car along and at the bottom of a hill you run out of Gas. You try to push the car uphill, against resistance and gravity, to the Gas Station you know is just ahead at the Top. You might make it...but what a chore! But hooray! 7 of you Buds come along, lay hands on the Fenders and together you just about effortless move that car up the hill.
Well, brook no mistake, accurately resonating a solid's molecules at any real volume with a single Transducer is a Yeoman's task. Always has been. Background Music? Sure. Moderate entertainment levels? absolutely. Full blown high volume Home Theater or Critical Listening? Best not send a single Boy to do a Man's job. But call out the entire 5th Grade class and see how fast you get it done!.
So now I gotta explain the difference between db and SPL production. (...no more cute examples....I promise...)
The Transducer produces Resonant frequencies.
The Solid it's attached to accurately resonates to said frequencies.
The Frequencies spread out across the opposite surface the Transducer is mounted to, each specific frequency finding it's own specific saturation point where it resonates the molecules to that frequency. No Frequency interferes with another...no cancellation occurs (...when units are properly spaced...)
As the surface of the Solid resonates, the air (ie: volume & pressure) itself that lies against the resonating surface sympathetically resonates, and that imparted energy cascades outward in a chain reaction of resonant energy transference.
The Audio Transducer's 180 degree hemispherical dispersion creates what can be considered to be the most perfect example of a omnidirectional sound dispersion pattern that could be obtained from a flat planar surface. As such, very effective db levels can be obtained, levels that are not accompanied by the normally expected Sound Pressure Levels that would otherwise be expected from such decibel levels.
This decided lack of sound pressure means that many acoustic concerns and considerations are effectively negated to a great extent...if not indeed actually eliminated. (...The Transducer uses this ability to excel at the art of Sound masking...)
For Red Top, the purpose of the design was to deliver the maximum aural and physical presence possible, but at the most comfortable decibel levels. On the past I've used all manner of amplification t accomplish such tasks. Everything from lowly Pioneer and Panasonic Receivers to Sony's and Yamaha s. I've seen Harmon Kardon Citation Amps...McIntosh s...Carver Studio Grand...Krell...and a few European Esoteric s that cost as much as my last 2 cars combined.
But in the end, it's all about simply having enough "clean" power and reserve headroom to be able to deliver unadulterated, accurate amplified frequencies to the transducer, and then using the correct number of devices needed to energize the mass of the solids involved without over taxing a single unit, or trying to over saturate a material with too much focused resonant energy from a single unit or a combined array of the same.
Too whit, it's no stretch to be able to understand that "expense" does not always relate to "effect. Judicious choices of equipment combined with effective design, adequate construction, and yeah....a bit of a crazed desire to do what many feel is patently impossible, can combine to deliver something that defies the accepted conventions of the A/V world.
Hey....did I mention about the Painted Screen?