Where's
the BASS?
First you should rule out any Phase Cancellation problems that may
exist in your system.
When
this variable is eliminated from the equation, there are primarily
two factors left that could cause this effect in your vehicle.
- Restriction
of AIR FLOW
-
Development of STANDING WAVES
If the
bass response in your system drops when you close the trunk, chances
are it is due to poor AIR FLOW, excessive STANDING WAVES or a combination
of the two.
AIR
FLOW
The
Bass Response will suffer if the trunk is sealed off from passenger
compartment so that AIR FLOW is restricted between the two areas.
Since sound waves are nothing more than moving air, any reduction
in the AIR FLOW from the trunk will result in a reduction of the
bass response in the passenger compartment.
Can
I Get Some Relief Over Here?
To
cure this problem you must reduce the restriction of AIR FLOW between
the two areas.
This
can be accomplished by removing some insulation or other acoustically
opaque materials from behind the rear seats, under the rear deck
or beneath the rear package tray.
If
this is not possible, the only other way to overcome this problem
is to create an opening in the acoustically opaque material between
the trunk and the passenger compartment that is causing the AIR
FLOW restriction. In most cases the back deck is the easiest area
to create this type of opening. The opening can be in the form of
a matrix of small holes, one or more ports, ducts or vents. Since
the object is to increase AIR FLOW, the opening should be as large
as possible without compromising the integrity of the vehicle.
With
this opening(s) in the acoustically opaque material the Bass Response
will pass through other acoustically transparent materials such
as foam or cloth found in the rear seats, package tray or rear deck
areas.
If
the opening is visible, it can be covered with a cosmetic grill
or a custom rear deck. This process requires custom install skills
and we recommend that you consult with a qualified installation
professional or have the work done by an Authorized SAS Dealer.
STANDING
WAVES
When sound waves of the same frequency come together at opposite
directions, they interfere with one another resulting in a full
or partial cancellation of the output at that frequency. This type
of wave interaction is known as STANDING WAVES.
What
Do I Get?
If
your Bazooka® subwoofer is positioned too far forward in the
trunk area, it may result in systems of COMPLEX STANDING WAVES,
resulting in a loss of bass output.
In
a trunk, the paths that sound waves take to the front of the passenger
compartment are rarely 100% acoustically transparent. This creates
acoustical resistance or reduced AIR FLOW
between the trunk and passenger compartment.
When
this sub-division of the vehicles air space is compounded by the
reflective and semi-reflective surfaces common in a trunk compartment,
the development of COMPLEX STANDING WAVE SYSTEMS are common phenomenon.
If
your Bazooka® subwoofer is placed near a semi-transparent surface
in the trunk, like the area under the rear deck or behind the rear
seats, the sound waves tend to bounce around in the trunk until
pressure forces these sound waves into the passenger compartment.
This
typically reduces the Bazooka® subwoofers output due to extreme
systems of COMPLEX STANDING WAVES and takes away from the overall
sound quality of the bass response.
There
is a Remedy!
If
you think you are experiencing output problems due to STANDING WAVES,
the good news is you can easily correct this problem by simply relocating
your Bass Tubes® enclosure(s) toward the rear of the vehicle.
When
a Bazooka® subwoofer is loaded into a corner at the rear of
the trunk the sound waves reflect off of the acoustically opaque
corner and travel forward in a direct path towards the passenger
compartment, reaching the listener with fewer STANDING WAVES and
greater Bass Output.
Once
the placement of the Bass Tubes® enclosure is at the rear of
the trunk you should notice a marked improvement in the quality
and output level of the bass response created by your Bazooka®
subwoofer product.
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