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PLANARS AND THE MAN WHO LOVED THEM - BY JOHN MEYER
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As an example, the Module 15 is crossed over, at 1250hz, at 6 db per octave for the Ribbons and 12 db for the bass drivers for minimum signal processing and maximum coherence. Hence integration is excellent and speed is exceptional. The family of curves (0, 30, 60 and 90 degrees) is also extremely tight (within a 5db window out to 3khz) which when combined with the systems minimal acoustic profile, yields a very broad, well focused and deep soundstage.
In a normal 2 way the woofer or mid crosses to a tweeter at least 2.5k. By that point, even a 5" is going to be down 18 db at 90 degrees. Things of course, get worse for 6 1/2" and 8" drivers even earlier. On a graph, the huge off axis suckouts display this characteristic. The soundstage suffers accordingly.
The Modules are available complete or in kit form. The September 1994 issue of "Speaker Builder" has an article on the Module 8 and 15 kits. Also, a number of people are using Dynaudio, Morel, VIFA Seas and Focal drivers for the low end. Aside from the fact we can not suggest exact crossovers, there is no reason to suspect their results will be anything less than excellent.
"Why Peerless?" is a question often raised. Given the high tech approach of the Ribbons, many people assume Focal or Dynaudio drivers would be a more suitable match. Although several of our overseas distributors are using these combinations, "the factory" feels they are not required since cross over is well (almost 2 octaves) before the Peerless 5" starts to break up. Peerless drivers are very well and consistently made. The only ones we have had to reject have been the ones we have poked screwdrivers through. The price of the more renowned drivers is due to their grace at frequency extremes. The manner in which the Peerless is used has its output down 20db at the point at which the other units would start to out perform it.
If a driver can be used in its "natural range", the design can be made much more simple which must be the ultimate design goal. Complexity has an unavoidable price. Once the signal is altered, the full integrity of the original can never be recovered. The ultimate speaker is a one way with no crossover, no diffraction effects which presents a high purely resistive load to the amplifier. We couldn't build that yet so we targeted a very simple two way.
As is typical of a Ribbon or panel driver, the vertical dispersion is poor. These systems are definitely made for the seated listener. However, tilting the speakers and/or using the 30" Ribbon can largely eliminate any standing dissatisfaction. No Holds Barred with 60" of Ribbon is the ultimate solution to vertical consistency.
In a home theatre application the poor vertical dispersion can be looked upon as a large benefit since it reduces stray vertical reflections which degrade the "sound localization" capability so vital to the surround effect. We will henceforth refer to the limited vertical dispersion as a sign of a "well controlled radiation pattern".
The fusion of home theatre and high fidelity is inevitable and this makes Ribbons in general and the Ribbon Modules specifically even more appropriate. For the centre channel, as well as the rear channels, both the 8" and 15" Modules are contenders. Note that the centre and rear channels are fed signals with the bandwidth of only 100 to 7000 hz. However, future versions of Dolby (especially digital) may expand the bandwidth to full spectrum. The bottom end can always be subbed but all speakers should have full treble capability. Dolby also recommends that all speakers have the same characteristics for best effects and smoothest integration.
There are numerous plans for sub-woofers and some very good results can be produced with a modest investment. Peerless for example produces a dual voice coil 8" (831858) and publishes several different alignments. The 40 liter cabinets are easy to build and the crossover is simple. Amazingly good bass therefore is readily available either in kit or ready made. Our Sub 2 (dual 831858s in an 80 liter enclosure with 1.5" walls) measures flat down to 25 Hz in-room. The Sub 2s weigh 100 pounds and after installing one, your vertebrae will measure flat as well.
In the past, sealed enclosures have been Newform policy. This was to avoid introducing any resonances into the system. Also, one of our benchmarks is how speakers handle the 1812 Overture with the real canons. Only sealed enclosures do a good job on this piece at moderately high volume. People have said the canons are not real music "so don't worry about it" but we didn't like the cones flopping around at medium high levels so we did worry about it.
With the development of the Modules we turned our attention to sub-woofers. We went first off with a standard Peerless alignment that included a port. The results were convincing. Bass was cleaner and more extended. And, of course, the cone "broke up" on the canons at medium levels. However, they did not break up on any other piece of music even at high levels. The short story is, never mind what happens at 7 to 15hz, concentrate on the music. (More on concentrating on the music later). Ported designs are great as long as the design is flat to the low 30s. Above that, sealed designs offer a graceful rolloff in what is still the music spectrum. Yes, this is a theme, graceful decay before strained extension.
Even if you are a opera fan, would you rather listen to John Denver sing "Rocky Mountain High" or Bizet's "Pearl Fisherman"? Lets use and enjoy things in their natural ranges folks and stop whipping the horses for the last 2 miles per hour.
No Holds Barred is our top of the line system which was running in prototype 18 months ago. It was designed to operate in large rooms and produce high SPLs and naturally, very high fidelity. Very large enclosures housed dual 12" woofers which crossed to dual prototype 30" Ribbons at 500hz. Even we thought they were ugly and they never went beyond very crude prototypes. Whether the 30" Ribbons could have met all performance requirements and worked down to 500 hz is as much of a question as the fidelity of the 12"s at 500hz. In any case, we felt the market was looking for smaller speakers rather than larger ones and devoted our efforts to the Modules, "the large panel sound in the small package".
The idea of "No Holds Barred" didn't leave us however and the concept was brought back to life in a far more refined form when we received a phone call from an end user in Oregon. A fellow addictee of film driver definition, he wanted large panel sound in a format that would fit on his 4.25" vertical window frames without looking like an overcast.
It was great to work with someone with a clear vision who can articulate their objectives and ideas while still being able to lay back enough to allow both of you to work out the solution. The result is what went into this individuals home.
NHB is the logical extension of the Modular Series. The system has dual 30" Ribbons per side stacked in a line source. This Ribbon column goes on top of the dual mid bass enclosures for a combined height of about 85 inches. The mid bass cabinet width is 7 1/2" (we use 1 1/2" MDF here as opposed to 3/4" in the Modules) and the 3 1/4" Ribbon column is anchored by a set of retractable arms which allow it to either nest on the wall or extend up to 3' for critical listening. The Ribbons column can also be pivoted over about 120 degrees. These mid-bass/Ribbon arrays can be mounted on either the front wall or the side walls. The bottom end is handled by a Sub 2 on each side. Sensitivity is 92/93 db and rated impedance is 4 ohms.
The side wall mount is ultimately more appealing since the speakers can be moved far away from front wall, producing truly unsurpassed soundstage depth. The Oregon user must have them on the front walls but this is a small compromise to begin with (given the 3' extension) and should be negligible once the "Room Tuners" have breathed on it. This individual also mandated Solen and MIT caps, foil inductors in the external crossovers with Kimber internal wiring and Norsorex isolated drivers and Ribbon brackets. In terms of isolation, NHB is off to a good start with the three Modules (Ribbon stack, mid/bass and sub enclosures) being totally separate to start with. The custom approach is an important part of NHB and every installation must be treated differently because once even the mid-fi level is reached, the room and the setup become dominant factors.
So what is this Oregonite going to run with NHB? An Etude Tuner, Mark Levinson 38S pre-amp, Levinson CD transport and DAC and probably a Bryston 8B amp with Flatline speaker cable and possibly interconnects. The audio will be mated to a roll down screen, ceiling mounted projector video installation. The Ribbons and mid-bass enclosures will extend at least 2 1/2 feet in front of the screen so there is great potential for some superb soundstaging. The rear channels will be Module 15s and either the Module 8 or 15 will go in the centre channel if one is deemed to be necessary. In brief tests here, the Dolby "phantom" setting worked so well the centre channel may prove superfluous. Could it be that excellent off-axis response can send those bothersome centre channel speakers packing? The question is open.
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