TECHNICAL REPORT
RM 765/780/865
REFERENCE MONITOR SYSTEMS
- The first 61/2" and 8" Coaxial Reference Monitors
- Phase and Time Coherent Point Source
- Uniform Flat Response Across Expanded Dynamic Range
- Uniform Flat Response in Both 2 TT and 4 TT Environments
- Extended Bass Response -865 with 10" woofers
RM 765
RM 780
RM 865
NEAR-FIELD MONITORS
The typical placement of speakers in the typical room results in a confusion of sound. You and up hearing a lot of the room colorations and reflections mixed in with the direct source. Sure, you can spend even more money and equalize the room. Even then you may have to invest in an outboard crossover in order to compensate for the loudspeaker design.
Avoid all these problems with Fostex Near-Field Monitors. They are Point Source, coaxial speakers. All the sound emanates from a point reference, just like in nature, so all the sound reaches your ears at the same time. Stereo imaging is rock solid.
This design produces a "sweet spot" so you know that what you're hearing from the RM Series will sound proportionally the same in a car, on a hi-fi system or through a custom-tuned playback system in the studio.
An unusually low crossover point gives you another important benefit not found in conventional designs; vital midband information like vocals will not be modulated by high, moact low hequency sounds like kick drums.
The same RP batenied driver gives you uniformly flat high frequency response in all three models; the woofers increase from 6.5 inches to 8 inches to 10 inches. The two drivers in the RM 765 are the identical elements in the RM 865.3-way system, which simply adds a 10-inch woofer.
This larger system is also ready for biamplification. In our listening tests with 800W - 1000W per side, these beauties have generated 115 dB SFL at the console with no audible distortion. The Near-Field Monitors from Fostex give you clarity and punch and definition — as loud as you need it.
THE INITIAL REFERENCE
RP stands for Regulated Phase. It's a new transducer technology which has been under development at Fostex for the last ten years. So far, more than 20 international patents have been awarded. The first products with the RP Technology were headphones. The idea worked so well, the inventors immediately been applying it to the reciprocal transducer, the microphone.
A whole series of microphones now exists' with the same basic principles embodied in the new RM 765 and RM 780 tweeters. The essential idea of this RP Transducer is affat, thin film diaphragm onto which the voice coll is printed; this assembly is then suspended between magnetic circuits arranged on both side of the diaphragm, with the same polarities facing each other and the opposite polarities adjacent to one another.
The end result of this arrangement permits the diaphragm to be driven with absolute uniformity. Which means it doesn't sound differently at different levels. It provides the same uniform frequency response across an extremely wide dynamic range.
It won't break up, either. Which means there won't be the usual high frequency dislortion to mask the over-use of 12 kHz boost, for example.
Because the printed film diaphragm moves identically in both directions, and the entire diaphragm surface is with in the magnetic field, it by-passes all of the response variations caused by conventional mounting designs. There simply is no mechanically induced distortion in the RP tweeter. It functions as an edgeless device.
In this sense, the double spider design of the RM-Series woolers is the perfect complement to the RP tweeter. In a conventional single spider design, the compliance from one direction differs from the other. This difference produces unacceptable distortion, particularly in the second harmonic region. Fostex
engineers added a second spider in a push/pull complementary configuration to cancel the compliance effects of a single spider design. The result is a 10 dB improvement in second harmonic distortion. A 2° voice col/magnet assembly and a computer modeled bass reflex design complete the profile of what is definitive low end response in the Reference Monitor Series.
THE POINT SOURCE REFERENCE
These two exceptional drivers are first placed in a coaxial relationship, then time compensation adjusted in a true concentric design. So all the music arrives at your ears simultaneously, not unlike the natural phenomena of sound.
Both drivers are now phase coherent and time coherent. They now produce a point source reference so clean and well cellind that the experience approaches the theoretic ideal of a pulsating sohere. If shard to magine another close field monitor coming anywhere near the overall performance of the Fostex RM. Harder still would be to find one with uniform frequency resoonse in both 2 TT
and 4 TT environments. Most small reference monitors like the 765 and 780 are designed for rack wall or sofit mounting (2 TT).
Most small reference monitors like the 765 and 780 are designed to rack, wall or sofit mounting (2.1.1). Unlike the others, ours have a switch for free field or console mounting (4.1.1).
Regardless of the placement, the Fostex 765s and 780s may be switched (front panel, of course) for proper response. And because they are phase and time coherent, you can mount them vertically or horizontally. Rack adaptors and mounting herdware are available, and all holes have been pre-drilled for convanient interface with any standard rack. The problems of placement have been anticipated so that you can get on with using them.
THE FINAL REFERENCE
With all the attention digital audio has been receiving for some time, it's important to remember that transducers will still be at the first and final points of any audio chain for a long time yet.
t hostex, a quiet, ten year development of a new transducer technology has come full cycle.
From headphones to microphones and now to monitors. The new reference Monitor Systems from Fostex. Patented RP tweeter. Double Spider woofer. Coaxial with both Phase and Time Coherence for true, concentric point-source reference. Selectable 2 TT and 4 TT fields.
The rest of the information in this brochure is in the form of graphs and charts, specifications and other technical data. This kind of documentation is useful, even necessary in some applicationa.
But the final truth about these monitors, like all monitors, is subjective. It's in the hearing, your final reference.
When you audition the RM Scrics, plcase listen Near-Field Monitors. That's the way these remarkable speaker systems were designed to operate. They avoid the typical problems of room coloration and the Point Source design gives you a rock solid basis for stereo imaging.
The RM 765 and 780 are 2-way systems with 6.5-inch and 8-inch woofers, respectively. The RM 865 is a 3-way system with the FM 765 drivers and a 10-inch woofer, ready for biamplification.
They all give you a reference which will translate accurately to other playback systems. So if you work with sound, work with the Fostex Near-Field Monitors. The RM Series with patented RP Technology.
The Development and Design of a Flat Disp tragm, Printed Rickson Microphone Capitals, by 3 Hester, Japan, presented at the 72 to Convention of the Audio Engineering Society, October, 1992.
RM765
RM865
Mounting/Placement
The RM-765s and RM-780s are designed to operate within 3 to 4. Inet, of the listener for best imaging and spatial information. The RM-865s can also be used in the direct listening field, and since they generate higher listening levels, they can also operate as a coffit mounted Main Monitor cyclicm.
As the RM series uses co-axial drivers, placement is very easy. First, the distance from the listener to the speakers should be 1 to 2 times the distance the co-axial speakers are spread apar. Second, due to the controlled dispersion of these monitors, place the tweaters in the co-axial driver so they are "aimed" at the listener. Again, due to the co-axial driver design, the monitors can be placed horizontally, vertically or a combination of the two with no effact on the imaging. Also, the monitors, by design, are imaged pairs so they can be placed with drivers out, or drivers in when used horizontally.
Following these simple rules will ensure you are slways in the "sweet spot" and obtain the maximum performance from your FOSTEX REFERENCE_MONITORS.
FOSTEL CORPORATION (60-3 MYAZAWACHO, ANOSHMA, TOKYO, JAPAN 186 TELEPHENE 0425-45-6111 TELEX: 2042 212 FOSTEX J FAX 0425-46-3198 FOSTEL CORPORATION OF AMERICA 15431 BLACKBUEN AVE., NORMALK, CA 00550 L S.A. TELEPHONE 213-423-4112 TELEX: SAMPB
0530822851 @ AUG. 1985 FOSTEX Printed in Japan.
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