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DLS SOUND HANDBOOK - TROUBLE SHOOTING GUIDE
Installing car sound can sometimes cause
problems. If you are not satisfied with the sound
you could have made something wrong.
Some typical problems are described below with
hints for solving them.
1. Problem: Poor bass reproduction
despite of a correctly designed bass
box.
- Start with phase reversing the subwoofer to see if
this helps.
- If you are using more than one subwoofer make
sure they are connected in the same phase
(polarity), if not most bass sound disappears.
(The speaker cones are moving but will not create
bass sound).
- If the bass reproduction is improved when
opening the doors of your car the box is too large,
The F-3dB point is too low. Make the box smaller.
- Standing waves can "kill" some frequencies. Try
to change place for the box. You can also try to
make the bass port shorter, this will increase the
box resonant frequency.
In some cases the area under the dashboard can
work as a wave trap killing some low frequencies.
Try to fill this area and tighten it.
- Also check the signal cable. If yuor subwoofer is
connected in mono bridge mode and one of the
leads are broken in a signal cable the sound
becomes real bad.
- You must also have enough power, especially if
you have a small sealed enclosure the power
output should be at least 200 Watts RMS.
2. Problem: The real "kick" lacks in the
bass sound.
- The box is not correctly build, or the box is not air
tight.
- The sub amplifier does not get enough power, the
power cables are too small, the ground
connection bad, or some other things that is
causing voltage drop at high power outputs.
A cheap amplifier with unsufficient capacity in the
DC-converter can give the same result.
A good car battery with low inner resistance
(OPTIMA) or a Power Cap of 0,5
Farad or more connected to the power lead will
also improve the bass reproduction.
3. Problem: "Rumble" bass sound.
- The box tuning is too low, make the F-3dB higher
with a smaller box.
- Connect a subsonic high-pass filter, 30 - 50 Hz, in
series with the amplifier input.
- Use vented or sealed boxes. Avoid band-pass
boxes, they are more difficult to build, and if
theyare incorrectly designed they create a rumble
bass sound.
4. Problem: Poor bass reproduction in
a system without separate subwoofer.
- Is normally caused by incorrect speaker phasing.
Make sure all woofer elements in the system are
connected with the same polarity (phasing). Both
front and rear speakers.
This is easiest made with the use of a 1,5 Volt
battery. Connect the battery + to the speaker +
cable, and the - to the speaker - cable. All spea
ker cones must move outwards when the battery
is connected.
5. Problem: Interference sound from
the alternator in systems with a
separate amplifier.
- Is normally caused by incorrect grounding. Try to
connect all units to the same ground point. It
should be a place close to the amplifier where the
paint is removed from the metal surface.
- Poor shielding on the signal cables, or a
defective cable.
- The signal cable is placed close to the cars own
cable wiring inducing interference into the signal
cable.
- The input level control on your amplifier is set to
high, reduce the setting.
- Any extra cable must not be laid in a ring, shorten
the cable or lay it in zig-zag instead.
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