User manual FOCAL SUBWOOFERS POLYGLASS

[. . . ] Check with your local Focal dealer for further advice. Due to constant technological advances, Focal reserves its right to modify specifications without notice. Images may not conform exactly to specific product. [. . . ] Using a low impedance load to the amplifier effectively ensures it will work less hard. For connecting the subwoofers, they are effectively looped together in any series circuit. Then depending on how many subwoofers are to be included this looping will continue, until the last (in this basic case the 2nd subwoofer), will have its negative (-) connected to the negative (-) of the amplifier. Connections series and parallel, combined Depending on your installation amplifier(s), subwoofer(s), various combinations of series and parallel circuits can be used. The real advantage of doing this is to have a system with available power, but at the same time to ensure the system impedance load is optimum for the amplifier(s) used. 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. If you decide to `brew your own', it is safest to go for a bass-reflex type. This classic simple alignment usually give the best and most consistent results. See below regarding our proposals for the various volumes available per subwoofer. Vented boxes A bass-reflex system is more efficient than the sealed box since some of the energy from the rear of the cone is converted via the reflex port to add in phase with the main output. There is also a reduction of cone travel at the tuning frequency, so this system can also give higher power handling. However, at very low frequencies bass rolls off faster (24dB/octave). in simple terms , bass is louder , but not quite as deep. You can make a vent port from a piece of plastic pipe, or there are many profiled vent custom designed for loudspeakers that minimize turbulence (prevents what's commonly referred to as chuffing). 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. [. . . ] 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. Guarantee All Focal loudspeakers are covered by guarantee drawn up by the official Focal distributor in your country. [. . . ]