Amina AIW750E, Руководство по установке

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Testing the speakers
08
Important: Always test the speaker before plastering over it.
CAUTION:
Without plaster on the surface of the speaker it is highly efficient and will generate very
high sound pressure levels with minimal power input. Take care to protect your ears when
testing at this stage.
Using a multimeter and without the APU750 crossover connected, check the nominal
impedance (DC resistance) of the HF and LF loudspeaker at the amplifier end of the
speaker cable. Allow for approx. +/–10% for cable resistance. The impedance should be 4
Ohm for both speakers.
Amina recommends a tone sweep be used at a moderate volume level (0.5 Vrms). Such
a test will quickly highlight any buzzes or rattles that could be caused by loose screws,
cables touching the speaker or loose elements/studs within the wall itself.
If the plasterboard is not securely fastened to the joists this could also create a buzz or
a rattle. Apply more screws if necessary - particularly around the speaker location.
Ensure that the speaker cable is not touching any part of the speaker (or backbox) as
this can lead to buzzes and rattles. To avoid this it is advised to lay the cable behind the
mineral wool or other wadding.
If metal studs are used, ensure the crossover point of the studs are secured together.
This can be achieved by applying drywall screws through the wall surface and through
the metal joists. If they are not secure this may well lead to audible vibrations and
rattles.
Check cable continuity back to the amplifier by using a multimeter to mark up the
cables correctly for the HF and LF panels.
Play music to check for buzzes and rattles during transient peaks. Do not judge the
speaker’s sound quality at this stage. Once plastered over it will sound as intended.
Always connect the APU750 when testing, except when measuring impedance.
Perform these tests again after the plaster is dry.
If the correct 2mm thick plaster coat has been applied, the speaker face, when tapped
with fingers, will sound slightly more hollow than the surrounding areas of plasterboard.
If there is little or no difference between these two sounds it is almost certain the
plaster coat is too thick. This will compromise the speaker performance.
Amina have a lot more information available from its technical help desk for those wishing
to measure frequency response curves at different stages of the installation.
Please c44 1480 354390 for assistance.
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