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18 EURODESK SX4882 User Manual
Bay 8:
L7 & R8 equals the L/R recording input to the 2-tracks. On Bay 8 we have
hard-wired these to recording outputs 1 to 6 in order to drive all recorders
simultaneously. Copying from any 2-track source to all recorders may be done by
patching the source outputs into L7 and R8.
We have assumed you have a HiFi amp available to enable a variety of secondary
sources to be condensed into the XTRN (external) input for easy monitoring
selection via the HiFi amp’s input selector switch, if you want to record from any
of these sources, best patch direct from the individual outputs (17 to 22)
rather than the HiFi amp mix (15 and 16) for the cleanest result. (The exception
being vinyl, which will need to use the HiFi amp’s RIAA pre-amp to present the
mixer with a at response signal).
Fig. 8.4: Wiring for bay 8 (for advanced wiring scheme refer to section 11)
Looming problems8.3
Loom wiring is an art in itself, and it is worth taking time out to get it right.
First, it is important to avoid earth loops. (A looped wire acts as an arial,
picking up electromagnetic radiation.) Think of a tree: Every part of that tree is
connected to every other part, but only by one route. That’s how the total earth
picture for your entire studio should look. Don’t take the earth o your power
cable plug to reduce audible 50 Hz mains hum (or its harmonics). Rather you
should be looking at disconnecting the signal screen somewhere.
You could do worse than ensure that all screens are commoned at the patchbay
in which case all unearthed equipment would pick up earth from this point
via a single screen (more than 1 route = an earth loop), while mains-earthed
equipment would have all screens cut at the equipment end.
Some quality equipment has an independent signal and mains earth. ◊
In this case, at least one and possibly all screens should carry earth to
the equipment. Sometimes the only way to find out is “suck and see”.
Take care to ensure that using the patchbay does not disturb the studio’s earth
architecture. Always use short as possible patch leads with the screen connected
at both ends.
If you’re really serious about hum levels, you could run balanced lines wherever
appropriate. The earth wiring scheme would be the same as before. By shorting
the ring to the barrel for all balanced jack sockets connected to unbalanced
equipment, you could use balanced patch leads throughout. (There is no
percentage in wiring a balanced output to a balanced input with a mono patch
cord!) (See section 12 “(Un)balanced lines”.)
Having designed mains hum out of the system, make up your cable looms from
the patchbays outwards, and use cable ties, exible sheaths, multicores etc.
to keep the back of your racks tidy. It’s going to get very busy in there, and loose
cables will inevitably mean lost signals. Possibly even lost equipment!
Equalization9.
The variable parameters of the channel A and B equalizers on the
EURODESK SX4882 are described in sections 3.4 and 3.7.
Few people buying the EURODESK will need to be told how an equalizer works.
But how to get the best out of it? Well, that’s another story.
In the beginning EQ was an instrument for removing unwanted frequencies,
or compensating for imperfect microphone response curves, or bumps in a
studio’s acoustic. It was a corrective device. Tamla Motown turned that notion
upside down in the sixties with the novel idea that you try to nd for each
instrument a characteristic frequency not shared by the other instruments in the
mix. Then you whack up its gain. This makes individual voices punch through
a mix in a slightly unnatural but exciting way. In general, corrective EQ usually
involves broadband (slope) contouring, together with narrowband notching of
unwanted resonances. The narrower the notch or “Q”, the less the total signal
will be aected.
Finding bad resonances is made easier by first frequency sweeping in ◊
boost mode.
“Motown” EQ is achieved by applying boost in a fairly broadband way.
The broader the band, the more musical but less instrument-specic the eect.
Applying boost over a narrow bandwidth will sound “Honky”. The two semi-
parametric bands of the EURODESK EQ have had their Q xed at 1, a typical and
sensible value. For sounds which require drastic corrective EQ (remember no
MIDI instrument should need it), it is advisable to have a couple of channels of
fully comprehensive equalization in your rack. (You can always bounce tracks
though the outboard EQ, freeing up the unit for the next task). Check out our
BEHRINGER ULTRACURVE PRO DEQ2496, which promises to be another price/
performance buster.
The EURODESK EQ might be applied to a signal as follows: First, trim the LF and
HF shelves to achieve the required slope or “LOUDNESS”. (These controls mirror
the tone controls of a typical HiFi amp.) Now use one parametric band to boost
the nicest frequency, and another to cut the nastiest. Over all channels in the mix,
if too many of the nicest frequencies coincide, then you might have to settle for
second best in some cases! Often you might want to boost two nice frequencies.
Really nasty frequencies will need notching. Time to go outboard.
Why does the upper mid bell frequency go up to 20 kHz? A more pertinent
question might be, why has it taken so long to get there? After all, even 16 bit
(the lowest acceptable quality) digital audio sports a 20k bandwidth: surely if
20k is important then so is controlling it. OK. You and I will never hear a pure 20k
sine tone. However, Rupert Neve, the audiophile Guru, would argue that when it
comes to real instruments, what happens even above 20k may have a perceptible
eect on the listener. It seems that one reason why high- quality (½" at 30 IPS)
analog tape sounds better than DAT to many discerning ears is because,
although its frequency response begins to roll o at 12 dB/octave somewhere
around 15 to 20 kHz, it is not abruptly cut o at 20!
We have heard, or “detected”, a 20+ kHz low pass lter being switched in and
out when monitoring an analog master tape through a speaker system that
included piezo-electric tweeter elements capable of reproducing up to 40 kHz.
Perhaps less controversially it can be shown that if cut/boost is applied at 20 kHz,
a signicant portion of the resulting EQ curve for all but the tightest of Q’s
actually occurs in the audible spectrum, below 16 to 18 kHz. For example if the
BEHRINGER EQ is boosted by +15 dB at 20 kHz, the amount of boost at 10 kHz
will be 3 dB. The resulting EQ curve will bear no relation to one where 3 dB of
boost is applied at 10 kHz.
A good vocal signal can be enhanced by applying a significant ◊
boost in the 15 k region or higher, above the nasty sibilance region.
Especially effective if you’ve got a de-esser post EQ.
Use the LF cut to tighten up channels in a mix: maybe remove it only ◊
for the bass, kick drum, toms, tablas, didgeridu and other deliberate
subsonics. (When recording classical music ignore this advice).
All output / input pairs normalised!