ACCESS SUBWOOFERS
User Manual
4
Adjustment of low cut off frequency
The cut off frequency of a subwoofer is normally in the region of 60 to 100Hz. This is always dependent on
the particular installation and listening position. A frequency of 80Hz is a good compromise for effective bass
compared to listening quality.
Enclosures
Access subwoofers were developed for vented or sealed box according to the reference of the product.
Warning
The 25 A1 and 30 A1 must only be used in a vented box. Please refer to pages 6 and 7 for more information.
Warning
The 30 A1 DB must only be used in a sealed box. Please refer to page 8 for more information.
Building an enclosure
The construction should always remain strong and rigid, to eliminate any unwanted resonances.
A good material such as MDF (Medium Density Fibreboard) will effectively ensure this is possible. Choosing
the correct thickness of MDF compared to the surface area decided, is also critical to ensure the enclosure
does not vibrate. For this reason the general thickness recommended is 19mm MDF. Any loose components
such as the internal connections and cables should always be fixed securely inside. Damping material (foam
etc) covering all the internal walls of the enclosure, will further ensure it is free from unwanted resonances.
It is imperative that your custom designed subwoofer enclosure remains securely mounted at all times to the
vehicle.
Warning!
The improved power handling has allowed Focal subwoofers to play at very loud sound volumes
For this reason, we recommend caution be wisely applied, especially during long listening periods.
Excessive volume levels of more than 110dB can cause permanent hearing damage.
Recommended power ratings
Access subwoofers are already highly efficient, with improved sensitivity. Therefore, their use with amplifiers will
produce comfortable listening pleasure.
However used in a more high-end system, with more powerful amplification, the audio quality will be greatly
improved. It is very important to check that rated power of the amplifier is suitable to the subwoofers. Otherwise
they may distort, or possible damage could occur.
Always consult the owners manual of the principal source (head unit/amplifier), to ensure the power rating
is compatible. A safe guide is to ensure the maximum power of the amplifier is not greater than the nominal
power of the speakers.
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