The Suspension - Oracle PREMIERE User Manual

The Suspension

The fundamental purpose of a turntable s u s p e n s i o n is to act as a mechanical
filter for outside vibration. T h e major source of these outside vibrations is your
loudspeakers w h i l e playing m u s i c , a n d this interference is c o n d u c t e d through
the air, a n d via the structural m e m b e r s of your listening environment. T h e s e
vibrations are difficult to deal w i t h because they consist of the w i d e range of
frequencies f o u n d in m u s i c .
A n y vibrational energy a b o v e the tuned turntable s u s p e n s i o n frequency is
prevented f r o m entering the playing s y s t e m , and for this reason it c a n be
generally stated that the s u s p e n s i o n frequency s h o u l d be as l o w as possible.
The s u s p e n s i o n of the P R E M I E R E is tuned to 3.5 Hz — well under the
b a n d w i d t h of any m u s i c likely to be reproduced. It s h o u l d be noted that while
the P R E M I E R E ' S s u s p e n s i o n has b e e n optimized to filter out musical f e e d b a c k , it
m a y be prone to disturbance arising from footfalls on compliant floors —
particularly w h e r e the floor's resonant frequency c o i n c i d e s w i t h 3.5 H z . In s u c h
instances, the r e m e d y consists of mounting the turntable securely on a stable
foundation, for e x a m p l e , a load bearing w a l l .
In the interest of G R O O V E I S O L A T I O N ™ , it is of vital importance that the
s u s p e n s i o n d i s p l a c e s the s u b c h a s s i s in a vertical direction only. A s p r u n g
s u b c h a s s i s turntable must exhibit no t e n d e n c y t o w a r d s a rocking or s w a y i n g
motion. S u c h m o v e m e n t w o u l d c o m p r o m i s e the filtering capability of the
s u s p e n s i o n a n d a d d flutter distortion. T h i s is b e c a u s e the platter (and therefore
the groove) is d e c o u p l e d from rotational m o v e m e n t of the s u b c h a s s i s by the
bearing, but the tonearm is not. In that case, the tonearm w o u l d s h o v e the
cartridge forwards a n d b a c k w a r d s as the s u b c h a s s i s oscillates, resulting in
c h a n g e s in the effective groove s p e e d .
W e have paid particular attention to this problem in the d e s i g n of the
P R E M I E R E . In c o m m o n w i t h previous O R A C L E turntables, the centre of gravity
of the entire floating a s s e m b l y is at the s a m e height as the fixing points for the
springs. T h i s in itself greatly reduces any t e n d e n c y t o w a r d s rotational
m o v e m e n t . A l s o in c o m m o n w i t h other O R A C L E turntables is the m e t h o d of
leveling the s u s p e n s i o n by raising or lowering the entire spring a s s e m b l y instead
of c o m p r e s s i n g or expanding t h e m w h i c h w o u l d vary the tuning of the
s u s p e n s i o n in an unpredictable manner. In order to a b s o r b vertical s h o c k
transmission effectively, all springs have to be tuned to an equal frequency.
T w o major p r o b l e m s remain. T h e w i d e variety of different tonearms (of varying
mass) available on the market today m a k e s it almost i m p o s s i b l e to reach a state
of perfect s u s p e n s i o n equilibrium. Even if the user painstakingly tunes his
s u s p e n s i o n to a c c o m m o d a t e his c h o i c e of a r m , the often bulky tonearm cables
w o r k against G R O O V E I S O L A T I O N ™ by c o u p l i n g the s u b c h a s s i s w i t h the
u n s u s p e n d e d base, and by encouraging rotational m o v e m e n t of the s u b c h a s s i s .
T h e s e p r o b l e m s have been eliminated in the P R E M I E R E by designing the
tonearm and turntable as one harmonious s y s t e m . W i t h a precise k n o w l e d g e of
the F I N A L E t o n e a r m ' s m a s s , w e have been able to adjust the s u s p e n s i o n of the
P R E M I E R E a c c o r d i n g l y . T h e F I N A L E ' S cables d o not c o n n e c t at the base of the
arm, but into a box w h i c h can be placed onto the unsprung acrylic base. S i n c e
the only c o n n e c t i o n b e t w e e n the tonearm and the junction box are the thread­
like interior leads, the problem of cable / s u s p e n s i o n interaction is eliminated.
The P R E M I E R E ' S s u s p e n s i o n can be tuned to a c c o m m o d a t e any other tonearm
if the user so desires.