Time to lay on some power. Connect the earth first. Then 12V power, then remote. Then
connect in the RCA cables and you can move onto setting up the gain and sound controls
on the amplifier (the fun bit!)
Setting the “Gain” or “level” on the amp is a crucial aspect and needs to be done with care,
otherwise you can easily damage your equipment. Before we move onto this we need to be
sure the crossover settings are right for the application.
If you have an active crossover elsewhere in your system (such as the head unit) then you
may wish to set the crossover switch on the amp to OFF. Otherwise, in most cases, this must
be set to ON.
We recommend a LPF of about 100hz initially as an excellent starting point for most car
woofers. Try 80Hz and 120Hz too – you will notice the sound change. If you are running a 15
inch woofer then you will want to be looking at a lower crossover frequency (like 80Hz) – if
it’s an 8 inch driver then you may want to go up to 120, 150 or even higher.
Once your crossover settings are set up, you can move on to the gain or “Level”. This bit is
REALLY important!
Before you do anything else, please ensure the BASS BOOST knob is set to 0 – I.e. switched
off. We also suggest you turn the bass remote level to a mid setting to allow adjustment later
to taste.
Next, you need to learn about the subsonic filter. This is a crucial part of the setup. When the
music frequency goes lower than that which the subwoofer system can reproduce with any
guts you are wasting a lot of energy asking the amplifier to create those parts of the music.
Worse still, your woofer will try its best to create them and find itself moving backwards and
forwards at very large levels of excursion and distortion from the overstretched amplifier.
Many bass amplifiers do not have subsonic filters – this is MADNESS and results in a lot of
burned out woofers and amplifiers. Many bass amplifiers DO have subsonic filters that their
owners do not understand – this is MADNESS and results in a lot of burned out woofers and
amplifiers!!!
As a rule of thumb you should set your subsonic filter to about 30Hz – this is a generalization
because obviously different subwoofer setups can play to different low frequencies.
Something like an 8 inch sub in a ported box designed to be very punchy will struggle
to get below 50Hz – in which case inch up the subsonic to that level to improve all round
performance and protect the components. If you have a 15 inch woofer in a well sized sealed
box that is designed to sound low and atmospheric then you may be able to come down to
20Hz with the filter. As you turn the filter up you will hear it stopping the low bass from being
played – but you will notice that you can play the music louder with less distortion. You need
to set this to optimum balance later.
