stands for mass of system.
Similar phenomenon is observed in arm-cartridge
assembly as it reproduces sound from record disk.
Graphically, cartridge compliance may be likened to
spring, and arm pivot to weight.
This is what is called arm resonance in low frequency
area, and there are as many resonance sources as
there are pivoting gadgets in tone arm.
At such a frequency of resonance arm becomes very
sensitive to vibration and, even when frequencies of
'flat' characteristics are reproduced from record, arm
resonance causes larger output than true to record or
'peak' phases (See diagram 3). At frequencies higher
than arm resonance, arm does not so vibrate at all,
and cantilever oscillation alone translates into output.
But at frequencies lower than that, cantilever and arm
oscillate together and fail to generate electricity. This is
why arm resonance frequency 'fo' is called low sound
reproduction margin.
With conventional type tone arms vertical and horizontal pivots are placed in close proximity. This
causes these two resonance sources to vibrate at the same frequency, as if vibrating as a unit. Peaks
then become larger and so much harder to damp.
The Bi-axis type DV-505 separates one pivot remotely
from the other. It thus encounters two peaks
simultaneously, but each peak is smaller than the two
put together, and horizontal resonance peak is
effectively cut by a couple of unique dampers (See
diagram 4), for the following reason :
So-called '45-45' record groove cutting method which is presently in use, does horizontal cutting at
same phases of input signal and vertical cutting at inverse phases. Because sub-100Hz wave lengths
elongate for more than several meters, stereo recording of low sounds produces, almost
comprehensively, same phase signals for both right- and left-hand side channels and, naturally,
signals for horizontal cutting come excessively to the fore. Then considering disk structure, it Is not
possible to impress on it deep-going low frequency signals.
The DV-505 has solved just that. By reducing peaks over all, it adds to low frequency area stability.
Also, it faithfully tracks surfaces so warped that no other tone arms could negotiate well, and thereby
limits effect of such warped disks on sound reproduction. The DV-505 an out performer. |
ACEC
