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Manual-10

Delay vs. Frequency Table

If you do not have the equipment necessary to electroni-

cally align the system as described in the previous sections,
you may use the table below to obtain a rough and approxi-
mate
 phase alignment of your drivers. Measure the horizontal
displacement between the voice coils of the two adjacent
drivers sharing the same crossover point, then find the
column in the table nearest your actual displacement. Move
down this column to the proper Crossover Frequency as
indicated on the left of the table: the corresponding DELAY
knob setting will then be the closest for your system. For
example, if you have a two-way system crossed over at 800
Hz with the compression driver voice coil located about 9"
behind the woofer voice coil, the Delay knob setting corre-
sponding to a 9" displacement at 800 Hz on the table would
be “5” as indicated on the front panel.

In order to phase-align two drivers you must observe only

the crossover frequency, which is common to both drivers.
Pink noise can be used if all other frequencies are disre-
garded, since room acoustics and imperfect driver response
will cause erroneous alignment attempts. Using pink noise as
a source, each driver is individually tuned to an arbitrary 0
dB level on the analyzer display only at the crossover
frequency
. When both are turned on simultaneously, the
combined response of the two drivers should read +3 dB
higher at the crossover frequency on the display. If the drivers
are not phase-aligned, some cancellation will occur on-axis,
resulting in a combined response less than +3 dB. Turning up
the DELAY control causes the lower driver to electronically
move backward until the analyzer reads +3 dB; then the two
drivers are electronically aligned and the on-axis cancellation
is eliminated (see Figure 2 on page Manual-6).

                    Voice Coil Displacement (Inches)

(Hz)

.75"

1.5"

3"

6"

9"

12"

15"

18"

21"

24"

70

1

1.5

2

2.5

3.5

5

6

7

8

MAX

80

1

1.5

2

2.5

3.5

5

6

7

8

MAX

100

1

1.5

2

2.5

3.5

5

6

7

8

MAX

150

1

1.5

2

2.5

3.5

5

6

7

MAX

200

1

1.5

2

2.5

3.5

5

6

7

MAX

250

1

1.5

2

2.5

3.5

5

7

8

MAX

300

1

1.5

2

2.5

3.5

5.5

7

MAX

400

1

1.5

2

2.5

4

6

8

MAX

450

1

1.5

2

2.5

4

6

8

MAX

500

1

1.5

2

2.5

4

6

8

MAX

800

1

1.5

2

3

5

7

MAX

lk

1

1.5

2.2

3

6

MAX

1.2k

1

1.5

2.2

3.5

MAX

1.5k

1

1.5

2.3

3.5

MAX

2k

1

1.5

2.3

MAX

2.5k

1

1.5

2.3

MAX

3k

1

1.7

2.4

MAX

3.6k

1

1.7

MAX

4k

1

1.8

MAX

6k

1

2

MAX

7k

1.2

MAX

C

r

o

s

s

o

v

e

r

 F

r

e

q

u

e

n

c

y

Displacement

Fig. 3. Vertical Driver Displacement

Summary of Contents for AC 22B

Page 1: ...TART The AC 22B can be either a Stereo 2 Way or Mono 3 Way crossover Labels above the controls refer to the unit being operated in the 2 Way Stereo mode Labels below the controls refer to the unit being operated in the 3 Way Mono mode The AC 22B is a fully balanced output version of the popular AC 22 and is equipped with 3 pin XLR type conectors instead of the standard TRS jacks All other features...

Page 2: ... MONO SUB mode the Channel 1 LOW MUTE switch mutes the MONO SUB Output Channel 2 s MUTE is inactive 6 LOW TIME DELAY This control adds from 0 to 2 ms of time Delay to the LOW OUT only This allows a low frequency driver to be electronically phase aligned with a high frequency driver whose diaphragm is situated behind the low frequency diaphragm Refer to Time Delay Adjustment on page Manual 6 NOTE B...

Page 3: ... is taken from Channel 1 LF OUT 6 SYSTEM MODE switch Set this switch for STEREO 2 WAY operation 7 POWER input connector Use only an RS 1 or other remote AC power supply approved by Rane This unit is supplied with a remote power supply for connection to this input jack Consult the factory for replacement or substitution This unit s power input is designed for an AC supply delivering 18 24 volts fro...

Page 4: ...ncy between LOW and MID Outputs The detents will assure maximum accuracy and consistency between Channels Refer to Selecting Crossover Frequencies on page Manual 6 to determine proper setting for your particular system 8 MID LEVEL This controls the Level of signal going to the MID Output NOTE The Channel 2 MASTER LEVEL control is automatically bypassed internally when the System Mode switch is set...

Page 5: ...ane This unit is supplied with a remote power supply suitable for connection to this input jack Consult the factory for replacement or substitution This unit s power input is designed for an AC supply delivering 18 24 volts from a center tapped transformer capable of supplying at least the current demanded by this product Using any other type of supply may damage the unit and void the warranty The...

Page 6: ...ers The detents assure consistent accuracy from Channel to Channel and unit to unit This is a distinct advantage over the continuously variable designs using low tolerance parts possible knob misalignment and panel screening variations Even with 41 choices it is possible that the exact recommended Crossover Frequency may not fall on one of the detents on the selector Not to panic for these sound r...

Page 7: ...he crossover frequency 5 Now release the MID MUTE switch on the crossover so that pink noise is heard from both the high and mid drivers Switch the display sensitivity to 3 dB on Rane analyzers not necessary with full scale analyzers and observe the display reading at the crossover frequency i If the display shows a 3 dB reading red LED on with Rane analyzers in the 3 dB mode then the drivers are ...

Page 8: ...tput LEVEL controls as outlined in the Setting Levels Section on page Manual 12 Time Delay Adjustment Using SPL Meter and Tone Generator Now that good quality realtime analyzers are becoming more affordable and easier to use there are few reasons why one of these should not be regularly used in any sound system If an analyzer is simply not available or for some reason inappropriate an accurate Del...

Page 9: ...stability in balancing the speaker stack You may want to raise it up as well to restore disper sion close to the stack If you cannot move the high driver then you will have to obtain an additional external delay source to align the high and mid drivers The built in Delay system in the AC 22B is designed to accommodate the majority of common speaker configurations if you encounter confusion or diff...

Page 10: ...nse will cause erroneous alignment attempts Using pink noise as a source each driver is individually tuned to an arbitrary 0 dB level on the analyzer display only at the crossover frequency When both are turned on simultaneously the combined response of the two drivers should read 3 dB higher at the crossover frequency on the display If the drivers are not phase aligned some cancellation will occu...

Page 11: ...W30 next to the Mono Sub switch and W11 behind the CH 1 Delay pot 3 To remove the Delay 1 circuit from the Low Frequency output remove the W30 and W11 jumpers 4 To get the Low Frequency output to work again place a long jumper from W30 Pin 1 to W11 Pin 2 5 The Delay 1 circuit is now removed from all circuits 6 To install the Delay 1 circuit into Channel 1 s High Frequency output find jumper W28 ne...

Page 12: ...are a few recom mended methods of setting the crossover Output Levels Setting Levels With a Realtime Analyzer NOTE If you are running two Channels tune up only one Channel at a time 1 Set all LEVEL controls to minimum leave Delay and crossover Frequency controls as set previously 2 Place the analyzer microphone at least 15 feet away from the speaker stack on axis dead ahead and about chest level M...

Page 13: ...t a 0dB reading on the meter After this point do not change the controls on the SPL meter 5 While leaving the LOW LEVEL control at the 0 dB adjustment just obtained press the LOW MUTE switch on the crossover so that the pink noise disappears from the bass speakers revel in the silence 6 Now slowly turn up the MID LEVEL control so that pink noise is heard from the mid frequency speakers Without cha...

Page 14: ... board so that the appropriate capacitor can be inserted Install the capacitor and solder the leads from the underside using fresh solder Clip the excess leads All features specifications subject to change without notice 520 438 SEP96 Rane Corporation 10802 47th Ave W Mukilteo WA 98275 5098 TEL 425 355 6000 FAX 425 347 7757 WEB http www rane com IMPORTANT NOTE CHASSIS GROUNDING If after hooking up...

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