CD Frequency
Your compression drivers’ spec sheet should have a suggested frequency for compensation boost. If so, just turn the CONSTANT DIRECTIVITY switch ON and set its knob to match that frequency. If your spec sheet doesn’t have that information, you can simply adjust the Frequency knob by ear, preferably using the same music as the actual performance (3.5kHz is a good place to start).
15dB
10dB
5dB
0dB
100Hz | 1kHz | 10kHz 20kHz | |
20Hz |
Constant Directivity EQ
Wait, there’s more: If you don’t have constant directivity horns, you can forget all this, and leave the switch OFF.
Or, better yet, you can use this CONSTANT DIRECTIVITY feature to enhance your EQ curve. By setting the Frequency knob fully clockwise, you introduce a very high frequency boost to the signal (above 6kHz). And in
Speaking of Mackie SR consoles: If you use both the AIR feature on an SR console as well as the AIR feature just described on the M•1400/M•1400i, you may be overdoing it. You won’t hyperventilate or anything, but it might cause your audience to experience ear fatigue from too much
More on Constant Directivity Horns
Back in the early ’70s, radial horns were the common mechanism for reproducing high frequencies. Radial
horns had a serious problem, though. The high frequencies tended to beam straight ahead, so if you moved
away from front and center
This was accomplished by using a smaller opening to the horn, using straight sidewalls in both the horizontal and vertical planes (radial horns typically have curved vertical sections that cause beaming), and providing a flare at the mouth of the horn to disperse the mid to high frequencies.
All
AMP MODE
This
1CHANNEL / BRIDGE / MONO
LOW CUT | INPUT | |
FILTER |
| |
TYPICAL | BALANCED | |
OR | ||
35 Hz | UNBALANCED | |
| STAGE |
|
| MONITOR |
|
| 100 Hz |
|
OFF | 170 Hz |
|
| CONSTANT DIRECTIVITY | |
| HORN EQ /AIR EQ | |
4.5 kHz | ON | |
|
| |
2k Hz | 6k Hz | OFF |
| AIR EQ | |
|
| TYPICAL |
AMP MODE
STEREO | MONO | BRIDGE |
TYPICAL | (CHS SUMMED) |
|
OUTPUT APPLICATION | |
FULL | SUB |
RANGE | WOOFER |
LIMITER (CH1 & CH2) | FREQUENCY |
| |
STEREO | 125Hz |
TYPICAL | |
ON OFF | 63Hz |
THRU | THRU |
INPUT | CHANNEL 2 | |
LOW CUT | ||
| FILTER | |
BALANCED | TYPICAL | |
OR | ||
UNBALANCED | 35 Hz | |
|
| STAGE |
|
| MONITOR |
|
| 100 Hz |
| OFF | 170 Hz |
CONSTANT DIRECTIVITY | ||
HORN EQ /AIR EQ |
| |
ON | 4.5k Hz | |
|
| |
| 2k Hz | 6k Hz |
OFF |
| AIR EQ |
TYPICAL |
|
|
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