Sansui LM-330 (1975/1976)

Sansui has again challenged traditional thinking in speaker system design. And again the results mean spectacular improvements in reproduced sound under actual listening conditions in your home. The new LM Series represents not just a revolution in design but a re-evaluation of high fidelity reproduction standards as well. Another great step in the realistic world of musical sound.

The unique multi-radiation baffle for the LM (Linear Motion) tweeter driver utilizes back radiated sound energy to enhance the overall sense of perspective sound image resolution and location in actual stereo application. It features three exponential horns to channel some of the out-of-phase backradiated sounds of the tweeter into the listening field. Essentially this unusual design emphasizes certain phase difference relationships in multi-channel music to give us a greater sense of stereo perspective. The fact that the separately-baffled LM tweeter driver has very free movement against input signals means better transient response too much better.

The proof of these improvements is yours to enjoy in three LM models. 

LM-110 (35 watts peak),

LM-220 (45 watts peak) 

LM-330 (60 watts peak).

Linear Motion Tweeter Driver

The LM Tweeter itself is a Sansui-exclusive Linear Motion Driver with a CCAW (Copper-Clad Aluminum Wire) voice coil to reduce moving mass and help improve transient response. The diaphragm features a steeply convex phase equalizer to eliminate phase interference inside the cone for better high-end response.

Improved Transient Response

Since the LM Tweeter is mounted on a separate baffle, as explained below, it requires no back cap or cavity to block out the strong and potentially damaging high pressure waves created by the woofer in the enclosure. The die-cast aluminium frame on the tweeter itself is ported to correspond to the three openings in the multi-radiation baffle, and the tweeter diaphragm is free to move to and fro in linear response to input signals with fast rise time. The result is free Linear Motion in the air on in technical terms, better transient response. The pure sounds of the LM Tweeter prove the  advantages over the blurred and muddy effects of less transient types at first hearing.

MULTI RADIATION BAFFLE

Three Horn-Shaped Ports

The special baffle for the LM Tweeter is mounted independently on the upper front of the LM enclosure. As illustrated its three ports in the tweeter assembly to channel the back-radiated sounds of the tweeter into the listening area in three directions - left, right and up. After testing over thirty full-scale LM prototypes, and the baffle as it appears here has been proven to emit just enough sound information in the high frequency range to achieve the unusually effective results .

Greater Stereo perspective

The sense of presence and ambience in stereo sound is much improved by the unique LM approach of course. But it is in the precise sound-image location effect that the new design truly shows its stuff. The emphasis on the difference in sound pressure levels inn the respective channels means that any and all between the channels sound images can be located exactly as they were intended by the recording engineer.

Enlarging each image as some speaker systems claim to do is not the answer to better stereo perspective. The LM approach in fact makes each individual image smaller with no loss in perceived level. In this way each has a more distinct focus or identity, more breathing room, more personality. And when they are located along the sterohorizot the perspective itself seems to widen and deepen as it does in live listening conditions.

Natural Response Woofer

The low-frequency driver in the LM has a number of unusually advanced features for mor natural bass respons, making it the perfect mate for the improved LM Tweeter system.

The superlight woofer cone is formed by a special non-press molding process and features a unique multi-corrugation design to achieve for proper stiffness and internal loss to create a living bass tone. To suspend this cone without defeating its best qualities. Sansui engineers designed an accordion-crease surround itself of appropriate stiffness and acoustical properties. The concave equalizer in the throat of the cone is still another new Sansui design and it serves perfectly to improve response near the crossover frequency. Finally, the LM woofer features a particularly strong magnetic circuit and voice coil, further extending the unit's ability to respond with linear motion to even extremely high level input signals with proper damping for improved linearity.

Special Crossover network

The crossover network in each LM model uses a special high-permeability core inductor to reduce DC resistance. This in turn provides a high damping factor and holds distortion to 1,0% or below even when maximum (peak) power is introduced. The non-polarized electrolytic type capacitors of particularly lower energy loss in the high (above 10,000 Hz) frequency are 1,500 Hz  and high frequency response can be adjusted by a rear panel control.

Luxurious Cabinet

Every LM Series speaker system regardless of size or power- handling capacity is crafted to blend harmoniously with all room decors. The polished walnut grained wood cabinet is solidly built and expertly finished with pride and the trim, pleasingly-textured front grille is a one-piece, removeable unit which protects both the separately-mounted LM Tweeter and the woofer cone.

SPECIFICATIONS LM-330

Speakers:

Woofer: 255 mm (10") Cone Type

Tweeter: 65 mm (2 ⁹/₁₆") Cone Type

Power Rating:  60 watts (peak)

Impedance:  8 ohms

Sensitivity:  92 dB/W (New JIS 1 m)

Frequency Range:  31 to 20,000 Hz

Crossover Network:  2-way 12 dB/oct L-C Parallel Type

Crossover Frequency:  1,500 Hz

Finish:  Simulated wood grain

Dimensions (W x H x D):  310 x 710 x 304 mm (12- 1/8" x 28" x 12")

Weight:  18,7 kg (41,2 lbs) net, 20,7 kg (45,6 lbs) packed

SANSUI LM-220

SANSUI LM-110