Description
Surround sound processor.  
 
Intended to be used with any conventional stereo preamplifier to achieve a 5-channel matrix from two (stereo) channels of information. It does not use Dolby® noise reduction or steering logic. The SDP1 has rotary controls for adjustment of level (volume) of center, rear-right and rear-left channels; a fourth rotary control allows choice of time delay for the rear channels from a menu of 5 options ranging from 22 ms to 45 ms. Rear and center channels are operated at full frequency bandwidth, with a minimum of signal manipulation or processing; this helps insure tonal accuracy, transparency and best dynamics. Delay is achieved through advanced digital tech- nology, while gain circuitry (12 dB overall) is fully analog. Front L and R channels remain completely unprocessed at all times for maximum fidelity. The SDP1 features both single-ended and balanced inputs and outputs (three outputs for connections to center and rear channel amplifiers). It is connected to a set of main outputs from the existing stereo preamplifier. Once the center and rear channel levels are set, the main preamp volume control becomes the master control.
 
 
Specifications
 
 
Frequency response 2Hz to 400kHz (-3dB point), Center channel  
Distortion (THD)  Less than .01% at 2V RMS output. (Typically less than .002% at 1kHz)  
Noise & hum Less than 30 uV RMS unbalanced IHF weighted, Center channel  
Gain 12dB maximum (6dB balanced to unbalanced, 18dB unbalanced to balanced)  
Input impedance 1.5 Mohms unbalanced, 3 Mohms balanced  
Output impedance 30 ohms unbalanced, 60 ohms balanced  
Maximum inputs    
Rated outputs Output before clipping: 18V RMS out balanced, 16V RMS into 600 ohm balanced load, Center channel  
Power supplies    
Power requirements 1200-270VAC 5040 watts maximum  
Other Output DC offset: Less than 2mVDC.  
Inputs: Left, Right (balanced & unbalanced).  
Outputs: Left, Right (pass through); Left Rear, Right Rear, Center Front (balanced & unbalanced).  
Gain controls: Left Rear, Right Rear, Center.  
Dimensions 19" (48 cm) W (standard rack panel) x 31/2" (8.9 cm) H x 113/4" (29.8 cm) D. Handles extend 11/2" (3.8 cm) forward of the front panel. Rear chassis fittings extend 9/16" (1.4 cm)  
Weight (5.2 kg) Net; (9.7 kg) Shipping.  
 
Le complément d'une chaine HIFI haut de gamme pour passer au 5.1 en conservant votre préampli  sans nuire à la qualité sonore, produit extrèmement rare, état parfait, 1 an de garantie avec la qualité de fabrication légendaire et le son Audio research: 2000€

> Rear and center channels are operated at full frequency bandwidth, with a minimum of signal manipulation or processing;
 
>a fourth rotary control allows choice of time delay for the rear channels from a menu of 5 options ranging from 22 ms to 45 ms.
 
en somme L/R on y touche pas ; encore heureux !
C ben c'est la somme mono ;  
 
et Back L/R sont juste time delayed 'au choix' , et probablement phase shifted  pour récupérer les 'petits signaux' hors phase entre L/R frontaux;  
 
bof... les DSP modernes sont beaucoup plus éfficaces dans ce genre de manips ; surtout que c'est meme pas des lignes à retard (qui reste en) analogique :
 
>Delay is achieved through advanced digital tech- nology,
 
se sont fourvoyés là Audio Research (amha)

Le son n'est malheureusement pas le meme qu'avec un Audio Research.

Très beau et bon matériel.