Specifications

Essentially, absolute phase refers to configuring the system so that the elec-

tro-acoustic drivers move toward the listener and produce a positive wave-

front upon the first cycle of excitation by source material. This means that at

the instant of impact, when the head of the kick drum moves outward

towards the microphone, the speaker cones also move outward.

Obviously, the phase integrity of the entire signal processing chain must be

maintained for this to occur. Is absolute phase audible? Should you be con-

cerned? Yes, it is audible and although subtle, it makes a big enough difference

to warrant taking the time needed to insure that the signal chain is phase-

positive throughout.You’ll hear an improvement in sonic impact, especially in

the lower frequencies.We recommend that absolute phase be kept positive

in all low-frequency devices whenever possible.This can be checked with a

small handheld type phase response test unit, available from numerous man-

ufacturers.Although it’s simple and easy to use the Phase Reverse Switch on

an Apogee Powered Subwoofer to determine its best phase relationship to

the full-range speaker system it is being used with; if the best position turns

out to be reversed, we recommend that you instead reverse the full-range

system(s) with phase reversal adapters, so that the subwoofer(s) can remain

in a positive absolute phase state.

(5) Placement on Tripod Stands

An optional internal stand fitting is available for the APL-220, -500, and -800.

The fitting is contained entirely within the enclosure so that no parts are

exposed. It is made out of high-grade aluminum and is fastened to the enclo-

sure with stainless steel screws. The stand fitting (see figure 7) allows the

APL-220, -500, or -800 to be placed safely and securely on a tripod or mast-

style stand fitting that uses a standard 1.5 inch outside diameter (O.D.) pipe.

A metric stand fitting sized to receive a 35mm O.D. pipe is also available.

For safety reasons,it is important that the tripod or mast-type stand be capa-

ble of supporting the weight of the APL-220 (75 lbs. /34 kg), -500 (80 lbs. /

36.2 kg), or -800 (94 lbs. / 42.6 kg). Generally speaking, only the largest and

best-constructed stands meet this requirement.

STAND FITTING

NUTPLATES

BOTTOM VIEW

Figure 7