Handbook for Sound Engineers

922 Chapter 25

Proper American broadcasters have taken quite a
fancy to a mutant PPM that is similar in dynamic char-
acteristics to BS4297, but with the level for the various
marks elevated by 8 dB. The marks give actual level
values (up to a maximum of +16 dB whereupon it’s
painted red) instead of the familiar 1 to 7. This is, it is
given to be believed, so that the signal levels generated
from control areas using these meters are similar to
those from older areas using (curiously nonstandard)
+8 dBm referred VU meters. Such are the levels they are
used to sending down interstudio and telephone lines.

The elevated-level PPM is an idea with some merit
when most of the material dealt with is prerecorded and
fairly predictable in level so it does not require an awful
lot of head room.

25.14.6.3 Other Metering

A preponderance of LED or FIP bar-graph-style

metering, or imitations thereof on GUI (graphical user

interface) screens, has caused nearly any sense of adher-

ence to any sort of accepted standard to be abandoned.

Most, and especially those on digital equipment, have a

very short—if not zero—attack time, which can give

rise to misleading readings, and such a wide range of

arbitrary release times that it is very difficult to interpret

their indications at all. The most an operator can hope to

do is to keep it dancing without pinning it. About the

best one can rely on is that the top of the meter repre-

sents 0 dBfs—or digital full-scale; nominal levels are

either 18 dBfs or 20 dBfs (close enough in

fader-pushing terms if a world apart technically)

depending on whether the influencing force previously

used black or beige meters, respectively.

25.15 A Typical Multitrack Console Described

Elsewhere in this chapter, versions of practically every

kind of electronic subsystem that finds its way into

today’s mixing consoles has been described, explored,

and analyzed. Here is a description of a complete

commercial multitrack mixing console, together with

the trials and tribulations of dealing with the electronics

as part of an overall system having a life and needs of

its own.

A system can be defined as a means of reducing the

versatility of its component parts. Ideally, there should

be no system, but practicality dictates that there must be

one. The thought is mortifying: hundreds of elements,

the microphone amplifiers, differential input amplifiers,

line amplifiers, equalizers, filters, and routing matrices

roaming loose and needing to be coupled together for

each individual operational requirement.

We need a saving grace, and fortunately there is one.

Engineering and balancing habits are pretty well

entrenched, giving rise to a few well-defined,

commonly used elemental combinations. Rationalizing

these combinations and arranging easy selection of

them as necessary is a good compromise. We’ve not so

much lost versatility as gained a family of operating

modes.

25.15.1 Channel System Example

This entire channel subsystem relies on the electronic

switching elements used being entirely transparent,

noiseless, distortionless, clickless, and other impossibil-

ities. Noise due to the potentiometric CMOS switching

Figure 25-93. Standard VU meter.

Figure 25-94. Peak program meter.