Specifications of ONKYO GrandSepter GS-1 Onkyo / Onkyo Grand Septor / Grand Septor

ONKYO GrandSepter GS-1
¥ 1,000,000 (1 unit, sold in July 1984)
¥ 1,200,000 (1 unit, around 1990 s)

Commentary

A speaker system designed based on a completely new theory of design and measurement aiming at the ultimate speaker.

The Grand-Ceptor is an all-horn configuration.
In principle, horn type speakers have good transient characteristics, but they also have disadvantages such as many time-domain distortions (multipath ghost distortion, reverb distortion, etc.). Theoretical analysis of on-kiyo has revealed that horn type speakers have very low high-order harmonic distortion compared with other systems in principle. Research and development has been carried out over a long period of time in order to realize an ideal speaker system by complete control of horn type speakers.
Although multi-pass ghost distortion and reverb distortion have been used to create sound because they are not necessarily objectionable, the Grandceptor eliminates these distortions for proper representation of the music.

Configuration
The GS-1 is a sound insulator and is divided into a low-sound reproduction block and a medium-sound reproduction block.
The bass block is divided into a low-frequency horn and a low-frequency compression driver unit with a back cavity, and the two low-frequency units are housed in separate back cavities of 40 liters each.
The middle and high sound block has a tilt adjustment circuit to adjust the sound axis.

Woofer
Two 28 cm cone type woofer W3060A are installed in the low range.
These units use a 10 cm diameter voice coil for a 23 mm effective diameter cone, and the magnetic circuit uses a 220 mm diameter magnet, the largest available at the time, to drive a 10 cm voice coil.
By combining a relatively small-diameter diaphragm with a large-diameter voice coil, the path of the sound wave inside the diaphragm is shortened and the transient is improved. In addition, it is strongly driven by a large magnet, and the movement of the cone is completely controlled by applying a horn load to the entire band of the woofer.

FRP laminated horn is used for the horn part.
The horn is sandwiched between FRP and anti-vibration materials. The back side of the phase plug is molded to match the shape of the driver's center cap and is covered with felt. The hyperbolic function is used for the change in the area of the horn, and the superelliptic function is used for the change in the shape. Both equations are solved by a computer, and the original model is obtained by using an NC lathe.

Tweeter
A horn type tweeter is installed in the middle and high area.
The diaphragm is a 65 mm diameter diaphragm made of titanium nitride that is integrally molded up to the voice coil bobbin, and the phase plug is ultra-precisely shaped by the lost wax method to obtain good high-frequency characteristics.
ダンプド FRP laminated horn is used for the horn. By stacking FRP and vibration isolation materials used for vibration isolation of iron bridges, multipath ghost distortion and reverb reverberation distortion are eliminated.

Network
The network circuit is a 2-way configuration and the network is a 12dB/oct. reverse connection configuration to eliminate the time delay caused by the circuit.
The network parts are installed in a distributed manner to reduce mutual interference.

Enclosure
The unit layout is based on the Constant Time Unit Array method to eliminate time lag due to the positional relationship between the woofer and the tweeter.

A unique layered structure is used to reduce the reverb distortion that occurs in the enclosure.
In general enclosures, reinforcement is used to suppress resonance. However, reinforcement only changes the frequency of resonance and does not absorb energy, so it can be adjusted but cannot be eliminated.
The Grand-Ceptor has a 7-layer structure consisting of six layers of Lauan and Yonematsu veneer, and is restrained by newly developed damping materials and steel plates to minimize vibration by orders of magnitude.

A glass plate is embedded in the top plate of the middle and high area regeneration block.

Other
By changing the connection of the terminal board on the back, you can use a special external equalizer or bi-amp drive without a divider.

Model Rating

Method	2-way, 3-speaker, all-horn system, floor type
Units Used	For low band : 28 cm cone type (W3060A) x2 For High Frequency : Horn Type (TW502801A)
Playback frequency band	20 Hz to 20 kHz
Max Input	300W(EIAJ)
Instantaneous maximum input	2,000W
Impedance	8 Ω
Crossover frequency	800Hz
Output sound pressure level	88dB/W/m 100dB/W/m (when external equalizer is used)
Internal volume	40 liters x2
External dimensions	630 mm W x 1,060 mm H x 615 mm D (Including RUNNET)
Weight	117 kg (77 kg for Woofer, 40 kg for Tweeter)

Photograph at the time of trial manufacture

A radial horn used in an experiment to verify multipath ghost distortion.
By removing the separator and support, and smoothing the part where the shape of the slow part suddenly changes, multi-pass ghost distortion is eliminated and the high range is smoothed.
Multi-Path Ghost The horn used in the experiment to fabricate a distortion-free horn is designed to ensure smooth changes in cross-sectional area and shape, and sidewall slope.
Although the shape of the slope is circular, it is smoothly changed to a super ellipse in the middle part and a rectangle in the opening part. Hundreds of prototypes have been built on computers together with formulas to calculate directivity and low-range reflections to determine the shape of the horn.
A horn carved out of white marble.
It is made using an NC lathe, and it was made when looking for a material which is hard to cause reverb reverberation distortion (distortion phenomenon caused by the reverberation of sound being subtracted).
In addition, various metals such as aluminum die-cast and steel, various molding materials such as lauan and cherry, various stone materials such as Mikage stone and marbles, and molding materials such as gypsum and concrete are used. The horn is actually made and measured, and studies are being carried out.
A horn made of polymer composite materials such as resin concrete (center photo).
Reverb It was created during repeated experiments to find a material that is less prone to reverberation distortion, and a structure with composite ribs on the back side of the horn to increase strength is being considered.
ダンプド FRP laminated horn.
FRP and dump materials used for steel bridges, etc., and prototypes with laminated steel plates for high-speed materials.
A group of prototype horns created in search of the best combination of materials that do not cause reverberation distortion.
Examination of polymer materials, improvement of characteristics of dump material, and change of lamination method of FRP and dump material were carried out.
Early prototype bass horn.
This horn is designed to achieve a low tone with good response, a low tone without delay, and a low tone with good braking.
Medium-term prototype bass horn.
At this point it is still a wooden parabolic horn, and it was decided to use a phase plug at this point.
Prototype low tone horn in the final stage.
An FRP laminated horn is used to obtain an ideal horn curve and to eliminate the reverberation distortion.
The last stage of the barrack set.
At this stage, audiophiles, audio critics, musicians, acousticians, and studio engineers gave a trial listening and it received a high evaluation.
Grandceptor development office.
Audio systems, computers, records, measuring instruments, and machine tools are installed.

ONKYO GrandSepter GS-1

Commentary

Model Rating

Photograph at the time of trial manufacture

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