BASSFACE DB4.1 User manual

The Bass Face DB4.1 amplifier is a high power 4 channel amplifier with a power
supply design inspired by that of a Mono-block amp. This is intended to supply
more than the required power, for high fidelity distortion free sound and increased
reliability.
BeforeBefore you even get the amplifier out of the box (realistically, you will have done
this already and boy it looks sweet doesn’t it!) you will need to install a suitable
wiring kit in your vehicle. You can use a high quality 8AWG kit for this product. If
you are planning to run a more demanding application such as a pair of 6x9
speakers in a shelf and a subwoofer then we would recommend a 4AWG kit down
the car, with the power split off into 8AWG close to the amplifier for maximum
performance. If you are planning to run multiple amplifiers you will need to up the
gaugegauge of the wiring accordingly. Do bear in mind that many manufacturers offer
wiring kits that actually come up smaller in true wire gauge than advertised.
To begin, disconnect the car battery, taking note of any required precautions
suggested by the vehicle manufacturer such as alarm or radio codes, or on board
computer or AGM battery requirements.
You need to find a suitable point on the firewall (bulkhead) to run the power wire
through. If you have to drill a hole, you will need to fit a rubber grommet to ensure
the wire does not get damaged as a short will ruin the whole setup and can be
very dangerous. The positive wire needs to go to the + positive terminal on the
battery. A fuse of appropriate size to protect the cable (for a quality 4 AWG kit we
suggest 50A) needs to be fitted in line and no more than 18” from the battery.
OnceOnce you have the cable in the car, run it back to the boot or to where you intend
to fit the amplifier. When you do this, be aware you will need to run the remote
cable and the 4 RCA’s from the head-unit back to the amp too, along with any
speaker cables going back the other way FROM the amplifier. If you only have a
2 channel RCA output on your head unit then you can run only one RCA and split
them using Y leads in the boot.
DODO NOT MOUNT THE AMP ON TO A SUBWOOFER BOX! This can result in
cracking of the circuit board and the amp will stop working. This would not be
covered under warranty for obvious reasons.
A common mistake is to forget that a car amplifier needs the remote 12V turn on
cable to see power for it to even work! If you only fit power and ground you’re
going to get…. Nothing!

If the wires you are running have to run over or go alongside other looms of the
car, try to cross them at right angles to avoid unwanted interference in the signal,
and try not to run them parallel with other cables either. If you can, run the power
and the signal cables down opposite sides of the car. This isn’t essential but if you
do get any interference once the job is complete the first thing to look at will be
separating these wires so if you can do it first it makes a lot of sense!
TheThe absolutely most important aspect of the power install is the earth wire. This
wants to be very securely bolted to the chassis of the car. We recommend drilling
a hole (take care not to drill through your spare tyre, brake lines or anything else!)
in the boot floor and sand off any paint to the bare metal where the wire will be
connected. A bad earth is a very common flaw in installation and can cause a
number of headaches later down the line so be sure to take care in doing this. Do
NOT use a self tapping screw to try and screw the earth down, as it will come
looseloose and impair performance. Other common disasters include trying to earth to
rear light mounting bolts, boot lock mountings and other ways to “trap” the cable
in the vein hope you might get a good earth. For every volt the amplifier doesn’t
see it requires TWICE the power to create the same output. That means poor
performance and a possible broken amplifier…. DO THE EARTH RIGHT!
Once your power cable, RCA’s and remote lead are all securely running through
the car to where you want the amp and the earth wire is fastened securely,
somewhere close to the amp, you can fit the amplifier.
TheThe amp needs to be mounted on a solid surface, favorites are boot floors, backs
of seats etc. Wherever you do choose to mount the amp, it needs sufficient
ventilation; 2-3” around will be enough. We do not recommend mounting an
amplifier on a bass box as the vibrations can cause damage to the internals of the
amplifier over time.
YouYou are now ready to connect your speakers! Take care that the positive on the
speaker is going to the positive on the amplifier. If your speakers are connected
“out of phase” then it will severely affect bass output as the 2 speakers will cancel
each other out acoustically.
ThisThis bit is VERY IMPORTANT. You need to ensure that the load you subject your
amplifier to is within specification and of a sensible nature. This particular amplifier
is suitable for running two stereo pairs at minimum of 4 ohms per side, or a
bridged mono load at 4 ohms – or a combination of those things. Just as important
is to remember that as well as the actual physical impedance you need to
consider the type of load you are going to subject your amplifier to. A single 8, 10
or 12 inch subwoofer of an appropriately matched construction and in a nicely
designeddesigned enclosure will be fine run off a DB4.1 amp at 4 ohms (assuming proper
setup) but you don’t want to try and run a pair of massive aluminium coned dual

voice coil monster woofers off it even though on paper you might well have a four
ohm load. We obviously recommend the Bass Face range of subwoofers and
speakers for ultimate compatibility. The other thing to consider with a 4 channel
amplifier is that as you load up one side of the amplifier the available power for the
other side is reduced. So if you run a subwoofer on one half of the amplifier the
available power to drive a pair of speakers on the other half won’t be as much as
if you were running only a small pair of rear-fill speakers.
TimeTime 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.
Firstly, ensure both SUPERBASS switches are set to 0.
SetSet up each half of the amplifier separately – so – here we go – first side of the
amp.
IfIf you are running Coaxial or Component speakers you first need to check the
“HPF/FULL/LPF” switch for this side is set to HPF and that the HPF knob is set as
described below. This High Pass Filter will stop any very low frequencies from
getting to the speakers, as these will damage the speakers, especially at high
volumes. As a rule of thumb look to use 200Hz for 4” speakers, 120Hz for 5”
speakers and 80-100Hz for 6” ones. As usual rules are there to be tested but
these figures will set you on the right track to a good setup.
IfIf you are running a subwoofer on this half of the amp the switch needs to be on
“LPF” or Low Pass Filter, as it describes, this will let the low frequencies pass
through. We recommend a LPF of about 100hz initially for most car woofers. Try
80Hz and 120Hz too – you will notice the sound change.
Once your crossover settings are set up, you can move on to the gain or “Level”.
This bit is REALLY important!
First,First, disconnect all other subwoofers or speakers so that you can hear only the
speakers (or woofer) powered by this side of the amplifier. Next, turn the level on
this side of the amp all the way down. Choose some music that you’re not
particularly keen on that has a good range of bass, treble and vocals (helps not to
get lost in the music whilst you work on the system.)
ThenThen go to your head unit and gradually turn up the volume until you begin to hear

Then go to your head unit and gradually turn up the volume until you begin to hear
slight distortion. This is normally about ¾ the way up the scale. This is the
maximum setting that you will EVER use from now on – make a mental note of it.
Next, turn the head unit down from here by around ¼. This builds in a little bit of
“headroom” so should you have a track that is recorded quieter than the others or
is at a lower bit rate, you can boost the volume without pushing anything into
distortion.
OnceOnce the volume is set on the head unit, go to the amplifier and slowly start to turn
the “Level” knob up, keep going till it is at a level you are happy with (that isn’t
going to deafen you!) or until your speakers are just about to distort. If they do start
to distort, turn back down till they sound perfectly clear – and then, because you’re
setting up a 4 channel amp you want to tweak it down a bit more for good measure
to take account for the effect that loading up both sides together will have.
IfIf you are setting up a subwoofer the procedure is exactly the same, except that
rather than hearing distortion in the conventional sense you will hear it as an
unclean bass note – you may hear a cracking, a metallic slapping sound or a
rattle. It is CRITICAL that you detect this sound and back the amp off to stop it
NOW. If you do not perform this step you will become another sad statistic in our
“rejected warranty” book – you will be ringing up in about a week wondering why
your woofer is toasted. Don’t be this sad individual!
Now,Now, disconnect the side of the amp you have just done and go back and set up
the other side.
Once this is done, connect both sides of the amp and listen to the whole thing.
You may find that there is an inbalance in the sound – now you can balance the
levels out very carefully. Remember that you can’t turn one side up without turning
the other side down by a corresponding amount.
OneOne final comment - If you are not running a subwoofer at all in your car you may
want to set the crossover switches to FULL - this will send the full spectrum of
sound to the speakers. However, it is likely that in most cases this will result in
your not being able to listen to the system without obvious distortion at even fairly
modest levels (depending on your speakers, installation and source unit) although
below the distortion threshold in this situation it will sound as sweet as possible.
YouYou will notice that earlier in the text we set the SUPER BASS (bass boost) to off.
This is because more often than not this EQ control is misunderstood and can
cause damage. The bass boost control ramps a range of frequencies in the bass
region that will cause more bass to be created than the signal coming in from the
head unit expects. It will also consume more power and can push a system into
distortion if the settings are not made carefully. An example of a valid use of bass

boost might be where your woofer system has an uneven response – as you turn
up the gain the upper region of the output becomes strained and begins to distort
but yet with low frequencies you are able to turn up the bass without distortion. In
this case, you would go back to the beginning of the setup instructions, get the
woofer playing at a modest level and then swing in some bass boost until the
distortion happens at the same volume level, regardless of the music you are
playing. Then, you would set the gain with the bass boost control in THAT position
– – to take account of that level of boost. You ABSOLUTELY cannot increase the
bass boost once you have already set the gain level – you’ll overdrive the amplifier
and burn something out.
You have done it! Enjoy your system!

To the right here is a
complete fail, the earth has
been attached to painted
metal and held with a washer
and a self tapping screw, this
will most definitely cause
serious resistance and while
thethe amp may appear to
function correctly initially, at
higher output levels, the amp
will strain and a component
within will fail very quickly.
DO NOT DO YOUR EARTH
LIKE THIS!!! PLEASE! :)
To the left, we see a hole drilled directly into the
chassis, big enough for a bolt and with access to
the nut from behind. The area has been prepared by
sanding off all the paint down to the bare metal. on
the contact side of the hole. Although you do not
need to sand off as large an area as you see here,
this was done for illustration purposes.
Here you can see the finished product, as
you can see there will be ample contact
between the ring terminal and the chassis of
the car. The bolt is the correct size to clamp
down only on the ring. It’s worth mentioning
at this point, a quick blow over with primer
will stop the metal rusting too!
As explained in the previous instructions, getting
a good quality connection on the earth is critical
for getting your equipment working correctly. If
you get it wrong, it WILL fry your amp and WONT
be covered under warranty! These pictures give
you very clear examples of good and bad
practices.
ToTo the left you can see what is commony
percieved to be a good earthing point. It is not,
there will not be enough pressure on the ring
terminal and oxidisation will occur on surfaces.
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