What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Altec Lansing Model Three II loudspeakers

Altec Lansing Model Three series II

Efficiency. What does it mean? It means a lot of sound out from a little power in - yes, always. It means large components and cabinets - well, most of the time. It means expensive systems - practically all of the time. But not with the Model Three. The Three is a system of moderate size and price with an efficiency level rivaling much more expensive systems. Efficiency, or sensitivity, is one of the most important yet most overlooked performance parameters. It indicates how much acoustic output a speaker can deliver for a given amount of electrical input. The larger the number, the more sensitive the speaker.

As an example, if a speaker has a sensitivity rating of 90,5 dB SPL, as does the Three, it will have more than 10 times the acoustic output as another speaker with a rating of 80 dB SPL, with the same input power. This is like multiplying the amplifier's power by 10. your 20-watt receiver just becomes a 200-watt super-amp.

The Three gets its efficiency from its 10-inch bass driver (which features a quality die cast frame) and optimally tuned, vented enclosure. The unique low-loss magnet structure creates a high level of flux in the gap, allowing the lighter-than-normal cone/voice coil assembly to be excited with small amounts of power.

A 12 dB per octave dividing network provides signal transition at 1500 Hz to a 4-inch  frame cone-type driver for high-frequency reproduction.

The hand-rubbed oak veneer cabinet and stretched knit grille form gracefully styled piece of furniture constructed of quality, natural materials that have virtually disappeared from other speaker systems in the price range of the Model Three.

 


Specifications

Speaker Components:

Low Frequency :  10" bass driver

High Frequency :  4" frame cone driver

Nominal Impedance:  8

Crossover Frequency:  1500 Hz

Enclosure Type:  Vented

Sensitivity:  90,5 dB SPL (Measured at 4 feet, 1 watt input referenced to 8 , using pink noise which has been limited to a bandwidth of 500 Hz to 3 kHz)

Frequency Response:  50 Hz to 20 kHz

Dispersion (Measured with pink noise limited to a bandwidth of 800 Hz to 8 kHz at a distance of 4 feet):

Vertical :  120° at -6 dB

Horizontal :  140° at -6 dB   

Long Term Broad Band Maximum Power:  35 watts (measured with a source of pink noise limited to the frequency response bandwidth of the system, over an extended time period)

Operational Power Range:  10 watts to 100 watts (Recommended for use with amplifiers between these levels)

Long Term Maximum Acoustic Output:  106 dB SPL at 35 watts  (measured with a source of pink noise limited to the frequency response bandwidth of the system, at a distance of 4 feet)

Finished:  Hand-rubbed oiled oak

Grille:  Acoustically transparent black knit fabric mounted on removable frame)

Dimensions (W x H x D):  318 x 609 x 292 mm (12-1/2" x 24" x 11-1/2")

Weight:  12 kg (26,25 lbs)

Nessun commento:

Posta un commento