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Manual-14

                   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

Delay vs. Frequency Table

If you do not have the equipment necessary to electroni-

cally align the system as described in previous sections, you
may use the table below to obtain a 

rough and approximate

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.

Crossover Frequency

Figure 3. Front-to-Back Displacement  Distance

Displacement

Summary of Contents for AC 23B

Page 1: ...it remains Pity See page Manual 6 for Mono 4 Way configuration In agreement with IEC and AES ANSI standards AC 22B wiring convention is pin 2 Positive pin 3 Negative return pin 1 chassis ground See t...

Page 2: ...ng Crossover Frequencies on page Manual 10 HIGH LEVEL control Sets the Level of signal going to the High frequency Output only Channel 2 MASTER LEVEL control Sets the overall Level of Channel 2 withou...

Page 3: ...still active and may be used as additional subwoofer outputs STEREO MONO switch Set this switch to the STEREO out position POWER input connector Use only a model RS 1 or other power supply approved by...

Page 4: ...MUTE switch Removes all signal from the Mid Frequency Output when pressed to the in position MID DELAY control Adds from 0 to 2 ms of time Delay to this Channel s Mid Output MID HIGH crossover frequen...

Page 5: ...equency amp and the CHANNEL 2 HIGH OUT to the right channel input of the high frequency amp MID OUTPUTS Connect the CHANNEL 1 MID OUT to the left channel of the mid frequency amp and the CHANNEL 2 MID...

Page 6: ...the Mid and High Mid Outputs NOTE Both the CHANNEL 1 HIGH LEVEL control and CHANNEL 2 MASTER LEVEL control are automatically bypassed when the AC 23B is switched to MONO on the back panel Adjusting th...

Page 7: ...turned off Remove the top cover of the AC 23B 2 Locate the 4 WAY 5 WAY switch see diagram 3 Move the switch from the 5 WAY position to 4 WAY 4 Replace the cover The AC 23B is now set for Mono 4 Way M...

Page 8: ...o the input of the subwoofer or bass bin amplifier LOW OUTPUT Connect the LOW OUT to the input of the low frequency mid bass amp MID OUTPUT Connect the MID OUT to the input of the mid frequency amplif...

Page 9: ...een Channels HlGH OUTPUT Connect the HIGH OUT to the input of the high frequency amplifier STEREO MONO switch Be sure this switch is in the STEREO out position Yes STEREO A Mono circuit is created whe...

Page 10: ...first into the realm of time delay and how to adjust it it might help to spend a moment here to re affirm why on earth this delay is really necessary For a short course on time delay Linkwitz Riley a...

Page 11: ...id driver at a comfortable volume 3 With a healthy but not uncomfortable volume of noise from the mid driver set the analyzer DISPLAY LEVEL control so the LED s corresponding to the high crossover fre...

Page 12: ...ophone until it is vertically midway between the mid and low drivers Repeat steps 2 through 5 using the crossover LEVEL control MUTE switch and next DELAY control You may start each series of steps 2...

Page 13: ...ill do not obtain a 3 dB reading you will have to physically move the high driver farther forward until the SPL meter reads 3 dB The amount of displacement corrections available from the delay depends...

Page 14: ...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 coi...

Page 15: ...d methods of setting the crossover output Levels Setting Levels Using a Realtime Analyzer NOTE If you are running two Channels tune up only one Channel at a time 1 Set all LEVEL controls on the crosso...

Page 16: ...se 1 Run pink noise into the crossover Inputs through the mixer or directly as is convenient 2 Make sure all crossover output LEVEL controls are turned all the way down and all amplifier level control...

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