Specifications

I
l
ir
la
l-
t
t
I
t
l_
l
I
l
t
I
t
t
I
t
I
I
Quafity
of
Recordins
The
quality of
a
magnetic sound
recording
depends on
various
factors,
some of which,
together
with
pertinent
advice,
are
quoted
be1o.w:
-
Oualitv
of
Masnetic Track
The
material
used
for the
sound track
(a
first-class
magnetlc
consisbency,
a smooth surface, a
perfectly
consbant
widbh
and
lrqnlr DTF \roT\r
j6nar{-nr*
in n}r*nj-.ino
nnnn ra^rr-l*^
uf 4ea
arL vu!J lJyvf u4IU
fII
uuuaritlllt3
t3UUu
LUSUIUS.
The tracks obtained
by
cementing
a thin magneLjc band
onto
the
recommend.ed.
"laminatedtt,
very
smooth tracks are most
suitable
very
little
wear on
bhe magnetic heads.
Wi-dth of Masnetic Track
coatlng),
its regular
thickness
of the
sound
film are
speciaffy
hec:trse l.hcrr o:rrgg
2,6 mm
-
Fulf-Track
-
la/henever
possible,
this track shoufd be
used,
since
it
provide
optimu-rn
sound
quality,
especia-I-Ly
with regard to dynamics. The
use of f1-Lms
with
a
single
row
of
perforations
is
therefore highly recommended. In
addition, fil-ms without
splices
(prints)
give
bhe best
results.
f,l mm
-
Half-Track
-
Since
the
sor.md energy
produced
when
rlrrning
a
haff-track
is
weaker than in
the case of a full
track,
a
greater
amount of
amplificatlon must
be
used
in
order to obtain
an equivalent
amourlt of output from
the speaker.
As
a
result,
the sound-to-noise ratio is
not
as
good
when
narrow
tracks
are used.
n a -- n,.--ts^-
-,-
*
-
'4*o'u-'-Track
-
The
factors
quobed
above apply
even more
to the
quarter-track
which should be used only in
case
of absofute necessity.
(For
instarice,
if the film
hac rlnrrhro nonFnnalions).
Even
in
this case, ib is
preferable
bo have
a
print
on
sv.!v yvr
f vl
qinolo
norlnrcl-od
fljLm
made Lo
which a fuff magnetlc
track can
be added.
Tn
addiLjon,
enl
i ooq aro o1 i mi no-l od i n thi a r^rq v
urLr
u
vvc.y.
Pnn'i onl-i nn Snaorl
The lidelitrr nf rennndrrntinn
in
lho
hiol.r fnanrronnioq r.rhinh epo m^ct
innnp*nr* fan
urre rr r6rr
rrsYuslrurcot !rrrf,urr
dr c !luou rulJUr
uallU f uf
o nnnd m'roianl ntrli*rr
ic nrnnnnlj6lql
Lo lho
qnoed
Of the tfaCk
OVer
the mop-nel, ln
Jyvuv vf
heads.
Speed
ol 24 f.p.s.
-
This
is the
standard speed
for
all
musica-L
tracks. both ontica]
-
and magnetic. Films
shot at this
speed -Lend
themselves
we-Ll
to high-quatity
sormd
proiection.
Actually,
the frequency
range
e.g. of a magnetic
sound track
goes
from
50
to 10.000
c/s
!
I
db.
Speed
of
f8 f.p.s.
-
Due
to lhe
slower
running
speed, bhe frequency
range is less
wide in the high frequencies
and music
cannot be regjstered
with
the
same flidelity
of
sor.rrd
as ir, the
case of fi-lns
shot at 24 f
.p.s.;
in
nost cases,
however,
quality
is
sufficient.
Imnnrtanno nf
(lnncl-oni
SnooA
The
result
of variations
of
the
projection
speed
is that
the sor.rnd. wil-L
appear
to
wavcr
("wow"
ef-Cect). This
is
a
phenomenon
that does not affect
speech very much,
but
the
effect
on musicaf
recordings
is much
aore noticeable.
The
following
precau-
tions must
therefore
be taken
so that the
projection
speed remains
constant:
-
keep
the
sor.rnd heads
and film drive
parts
on the
p"ol""tor
perfect-Ly
clean
(see
pages
27
and, 28);
-
take
care
that any spfices on the film
are
properly
made.
Tf nn hoo-inn-inc
z recnrdinq thp
qtnohoq.^na
dnoc nnf ennorr tn ho ohcnlrr.| ol rr mnf inn-+r
t
vrr
uc6lturrlf6
urrr6t
ur vvvJuvpu
uvuo lfu U dPPsal UU
UY
4UJV LUUvl.y
uVUf vrr_
1ess,
but
seems to
be
moving
sfowly
(about
1
period per
second), this need
not
give
cause
for
concern,
since
the difference
in speed
is very slighL. An
atbempt to correct
the
speed
would
cause
a change in
the recording,
and resuft
in
a
"wow"
effect
rvhen
playing
back. fn
such
a
case,
the recording
should
be
continued.
at the original
speed.
t
ii
t:
i
I
I
I
[,
39