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PLANARS AND THE MAN WHO LOVED THEM - BY JOHN MEYER
Just about 20 years ago, I walked into a stereo shop in Toronto and paused 10 feet inside the door. I was looking for the guitarist as the store seemed to be doing one of the "live" vs "our state-of-the-art equipment" demos that were so popular in those days.
There was no guitarist, only some large black panels raised about 3 feet off the ground. These turned out to be Dayton Wright electrostatics and they were my first exposure to film drivers. I was hooked. After that, there were many listening sessions and several meetings with Mike Wright, the brilliant but erratic (don't these characteristics seem to go together?) designer. I was designing part time and any audience with "God" as Mike was known in the audiophile community was to be coveted as the highly as the operating manual from a crashed alien spaceship would be today.
Despite the breakthrough nature of the sound, there were many problems with electrostatics in those days. Reliability, impedance, sensitivity, placement, frequency response and several other issues made ownership suitable only for those with both deep passion and deep pockets. Ribbons were also on the scene but the first available to the OEM market was the Strathearne panel. This unit offered the same kind of openness, transparency, definition and air as the larger panels but came in a smaller package at a much lower price. Nirvana!
Not quite. The magnets had a habit of voting with their feet, so to speak, by jumping into the gap and rupturing the diaphragm. A transformer was required and there were so many parts in its construction that rattled, the "music" continued long after the band had stopped playing. A spectral time delay plot of one of the early units would provide hours of interesting study.
But the fundamental promise of planar drivers could not be denied. With extremely low mass and driven over their entire diaphragm area, film drivers avoided the problems associated their heavier cone and dome siblings. Not only do cones and domes have far greater mass, they have far less directly driven area (the apex of the cone and the perimeter of the dome) with which to achieve perfect control. Planar film drivers are also inherently phase coherent over their entire bandwidth whereas cones and domes have a built in phase "smear" due to their depth (or profile).
Loudspeakers are merely air pumps. The speaker with the greatest fidelity is the air pump producing the fewest errors (room interactions aside). Film drivers have the greatest potential for making the fewest errors. OK, gas drivers or implants have the greatest potential for making the fewest errors but we can't make those yet.
When we began to develop our own Ribbon drivers (8", 15" and 30") in the late 80's we wanted to capture the musical characteristics which were so seductive in film drivers but do so in designs that would be easy to drive, easy to place and, above all, be reliable. The end products are mono-polar, magnetically shielded Ribbons with high impedances and extended bandwidths (approx. 1k to 20kHz in system). The entire driver is 3 1/4" wide by 2 1/4" deep and beveled at the front. The 3/4" wide diaphragm is within 1/8" of the front as opposed to being buried 1/2" or more into the magnet structure.
Hence the inspiration for the Newform Research line of speakers, kits and raw Ribbon drivers. The systems and applications described here are quite simple, yet the results rival the large film drivers in their strong points and greatly surpass them in their weak points.
The initial application of our Ribbons was in a line of full range speakers which utilized 8" Peerless drivers for the larger models and 5" Cambridge (Canadian manufacturer) for the smaller unit. The concept was to make very simple two way systems. That is, to build systems in which the bass drivers roll off before they start to beam or break up and far enough short of the trouble region to allow the use of minimal crossovers. The slopes we use are always 6db on the Ribbons and usually 12 db on the woofers. However, 6 db is now a possibility on the woofers on several models due to probable changes in Ribbon positioning.
Early on, we found an 8" bass driver was required to give acceptable (output extension, sensitivity) bass response. An 8" can be used reliably to about 1200hz. Beyond that, beaming sets in (heard as an off axis suckout which destabilizes the soundstage and tonally as the nasalness of the "cone effect"). These effects are a function of piston diameter and have little to do with on-axis response. Any design which runs its bass driver significantly past the piston point will pay in the above mentioned deficiencies. The majority of two way dome systems suffer from these shortcomings.
To illustrate this point, our Italian distributor once sent us two Focal 6 1/2" units. With a simple inductor in series, they exhibited the flattest frequency response I have ever seen to 3500 Hz where they died gracefully. My accountant could slap a good dome into a system with this woofer and produce a curve to kill for. On axis that is. The family of curves would still exhibit that familiar canyon between 1500Hz and 3000Hz.
The 8" systems work very well with the model R8-1 (single 8" woofer, 15" Ribbon, 1050 Hz x-over) being the most neutral and the R8-2 (dual 8" woofer, 30" Ribbon, 1000 Hz x-over) being the most suitable for placement well out into large rooms due to its prodigious bass response. The best soundstage is available with the speakers well away from the walls and the R8-2s deliver in spades. Since the same bracket is used on both the R8-1 and R8-2, it is possible to mix and match the 15" and 30" Ribbons to taste (or more probably budget and room configuration).
The Ribbons are mounted on top of the bass cabinets which is great for sound quality but not for aesthetics. This has been our biggest problem and will be solved (hopefully) when the slanted top grill hoods a la Ohm are finalized. Being only 3" wide and beveled with the diaphragm at the front, the Ribbons have a minimal acoustic profile which reduces diffraction tremendously. The diaphragm is only 3/4" wide so horizontal dispersion is excellent. These designs have less to get in the way of superb soundstaging than most other speakers on the market. (Note our adherence to the dogma that real improvements in sound quality can only come from the elimination of errors as opposed to compensation for errors.)
And now to the big caveat: the dreaded "spousal approval factor" (SAF). There is increasing resistance to having large irregularly shaped and un-colour coordinated objects thrust at odd angles into the main living areas of the house proud non-audiophile. We understand even the large panel name brand manufactures are having this problem. The difference is we can shrink our technology into much smaller packages while they are left with fewer options.
This consideration, along with the recognition of the need for integration of high quality audio and video, led us to develop the Modular Series. Our three Ribbons (8", 15" and 30") are mated to 5" mid-bass drivers in cabinets just large enough to hold all of the hardware. The 5" goes down to 100 Hz and depends on a sub for the rest of the bass. Modules give more placement options and a vastly lower profile. Aesthetics problem mitigated!
Room setup and speaker placement are critical issues and in some cases are more important than the loudspeakers themselves. The two main performance considerations are the bass and the soundstage. It is a very pleasant surprise when both of these factors can be optimized in the same location. The modular approach allows a solution of the two problems largely independently by placing the Ribbon Modules for optimum soundstage and placing the subwoofer for optimum bass. This is Nirvana!
Many people believe off axis consistency is also critical to a proper soundstage. That is, the on and off axis family of curves (leaving out the verticals) should be tight until the higher frequency rolloff inevitably splits them up. This consistency will yield a deeper and more focused soundstage because different elements of the sound spectrum will not be displaced in their spatial location relative to other elements.
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