Specifications

nal (unity gain), but with a high-pass filter applied. It is intended to be

employed as a crossover, if desired, for the full-range speakers used with

Apogee’s powered subwoofer(s).The output signal is balanced and filtered to

avoid DC offset. It is designed to feed a +4 dBv (nominal) line-level input.The

line driver in the APL-10, -12, and -SB is of an advanced design (Analog

Devices SSM 2141) that can easily drive a load as low as 1000 ohms. This

means that quite a few full-range speakers can be fed from this output simul-

taneously.

If multiple subwoofers are present in a system and the full-range speakers are

to be high-passed, it is prudent to use more than one high-pass output for

the sake of redundancy. If a large portion of the system is fed by a single high-

pass output and that output ceases to function due to power interruption or

any other reason, the resultant system failure would be more extensive than

necessary.

(5) Using the High-Pass Output

The High-Pass Output is especially effective when full-range speakers, such as

APL-500s,APL-220s, or APL-800s, are positioned on or adjacent to the APL-

10, -12, or -SB. In such a case, an overlap will occur between the low fre-

quency output of the full-range speaker and the output of the subwoofer. By

using the High-Pass Output, the full-range speakers can be “crossed over,”

eliminating a low frequency peak that would otherwise occur.

Using the High-Pass output reduces the low frequency power demand on the

high-passed full-range speaker; this allows the full-range speaker to operate

more efficiently, and in most cases, be played at higher levels before protec-

tive limiting is engaged.

NOTE: When the full-range speakers are NOT positioned on or near the

APL-10, -12, or -SB but flown some height above the subwoofer(s) or oth-

erwise located some distance from the subwoofer(s), it may be better not to

use the High-Pass Output to feed the full-range speakers because doing so

could result in a ‘disjointed’ sound quality. If most of the information below

100 Hz is coming from the subwoofers on the floor and all higher frequen-

cy information is coming from the speakers flown high overhead, a loss of

acoustic integration between the systems may result. For this reason, we rec-

ommend that you listen carefully to the system with the High-Pass filter both

IN and OUT of the circuit, to see which mode provides the most desirable

results.

(6) Signal Indicator

The APL-10, 12 and SB are all equipped with a green LED Signal Indicator.

This indicator receives its signal from the VIProtect

™ voltage and current

sensor circuit, and is intended to be used for verification that the subwoofers