BASSFACE GT Audio GT-SW8/4 User manual

GT Audio GT-SW8/4 2X4Ohm DVC 100w
RMS Subwoofer Driver-
Sealed/Ported/Free Air
Instruction manual

Thank you for choosing Bassface. From the simplest connector to our top of the range
amplifier - every element of these products has been designed to give you the best possible
performance for your money. Please take the time to read these instructions carefully as
they contain useful and important information. Modern high power audio systems can
generate voltages at the speaker similar to mains operated equipment – for some reason
everyone seems to ignore or forget this. Your wiring needs to be good to be safe. Please
remember this and take your time. Please exercise caution when setting volume levels –
powerful audio equipment can easily produce enough sound to permanently damage
hearing. Remember that audio competitors use ear protection when operating and
competing. Do remember that incorrect installation or abuse is not covered under warranty
– please make sure that your installation and any partnered product is suitable and
compatible. If you are unsure please seek qualified advice before proceeding. Always use
appropriate hand and eye protection when working with tools, and always work within your
capabilities as an installer. We offer a 12 month manufacturer warranty via your distributor
or retailer. Please retain your purchase receipt as proof of purchase. Please note that
Bassface operates a policy of continuous product development and we reserve the right to
change specification without prior notice. You can follow our process on our website by
reviewing the version history information.
Please note that we sometimes include information inside these manuals which we feel is of
potential value to the client on related subjects such as conversion charts, capacitance
values or wiring diagrams. Please feel free to copy any of this information since it is in the
public domain.

Before tackling the installation of the speaker, it is CRITICALLY important to follow at least a
basic break in procedure for the speaker. This operation will loosen up the moving
components of the speaker which will prepare it for heavy use. Failure to run a proper
break in can be responsible for failures such as ripped spiders, surrounds or tinsel leads. We
advise to feed the speaker with a range of tones from a clean power source at gradually
increasing amplitudes. Before you start, gently press on the cone - you will feel that it is
very stiff, and not compliant. You can imagine the forces at play if you try to run that
speaker like that in anger before break in. Start off by using the approximate resonant
frequency of the speaker (the FS), and run the speaker on the bench. Observe the speaker
carefully as you run the process - remember that the speaker will not have any power
handling as it is not in a box or baffle plate. Just run it up so that the spider, surround and
leads gradually get exercised. Don't overdrive the speaker - you DO NOT want to hear ANY
bad noises from it during this process. It's gentle exercise to loosen it up. Once you have
run the speaker for, say, an hour, recheck by switching everything off and pressing the
cone. You will feel that it is much softer. You should then run for another hour to complete
the initial break in. From here many more experienced people will wish to adopt their own
preferred break in procedure which is of course fine. From our perspective and from a
warranty point of view the minimum requirements are to run the driver as described for at
least 2 hours before installation in the final environment. Failure to carry out this process
will result in NO WARRANTY support on the speaker. If you have a failure of the speaker you
will be asked the warranty question to prove that you have read this manual and adhered
to the break in procedure. The answer to the warranty question is "BREAK-IN FOR THE
WIN!" Please repeat this phrase if you are asked to answer the warranty question. Later in
this manual we may reference specific break in procedures for this particular model. They
are recommended to be followed but not as mission critical as this initial period.

Before we move to the design and installation of the subwoofer it is important to
understand about woofer power handling. When we rate a speaker for power, we are
aiming to give the customer a good indication of the level of power that the speaker will be
able to cope with as a maximum value, when installed into a closed field environment (a
car!) using a suitably designed bass enclosure and running an intelligently set subsonic
filter and low pass crossover and when fed from an amplifier that is outputting clean, crisp
power (not a load of distortion!). To be clear, we are not attempting to rate for "continuous"
or "indefinite" performance - we are rating for a genuine, RMS value over the short term,
rather like what you might do to enjoy one song at absolute maximum level, or at the other
end of the spectrum if you are competing in sound pressure contests we are offering you
the "burp" RMS level. It is the system designer that is responsible for choosing equipment
that works in harmony together - speaker, enclosure, amplifier and source unit as well as
setup. There are vast differences in the fil power handling of a speaker system depending
on these factors, and "raw driver" theoretical power limits are only one factor in that fil
number. Heat management is the responsibility of the system designer, therefore, and we
will not accept warranty claims for burned coils under any circumstances. A burned coil is
always because of either bad setup (distortion) or bad heat management (too much power
for too long - choose a higher subsonic filter level, a lower crossover low pass point or allow
the hardware to cool down between periods of extreme load.) Lets face it, we all want to
run with a 10Hz subsonic in a massive enclosure and do huge numbers easily but that's not
possible in every case. You have to set expectations accordingly. A race engine might last 2
hours at the absolute maximum level of performance it is capable of. The same engine
running a lower state of tune might last many thousands of miles on the road. That's the

same engine in a different situation with different setup. Our speakers are no different than
this and the longevity will vary in a similar way depending on how close to their thermal
and mechanical limits they are run.
The first consideration is enclosure design. This is a complicated and technical subject. You
can use our recommended box design where we quote one, or approach your distributor for
advice. Please do not guess the box size as it is a very important part of your success with
the product. For the construction of the enclosure we recommend the use of MDF or
Weather Proof Ply Board (WBP) in 18mm thickness as a minimum. Do not construct bass
boxes from chip board. Improved performance will result from thicker box material - either
25mm or even laminations of thinner material are common methods for improving box
rigidity. Corner bracing is popular and works well, as do internal braces between walls.
Don't forget to take account of the volume of any inner bracing when you are optimising
the box size. When we are designing boxes we always allow an additional small amount
(say 0.25 cubic feet or a few litres) of extra space so that we can tune the box accurately
afterwards. You can't add space after but you can fill it with bracing and resin or other
objects to reduce it! On the larger subwoofers it is essential to make the baffle (the side of
the box where the woofer is affixed) from a double layer of 18mm MDF as a minimum. This
reduces box interference greatly and is proven to be a worthwhile exercise. DO NOT use
screws to fasten your subwoofer into the box. It works but they strip easily, can come
undone and do not offer professional repeatability in respect of service work to the
enclosure or speaker. We offer our BFTNUT.1 kit which has ten 60mm long high grade M5
bolts with matching T nuts as an excellent way of retaining your woofer to the enclosure.

Also take note that should you carpet the enclosure you will need to cut the carpet carefully
around the woofer. Do NOT bolt the woofer to carpet as it is porous and could affect the box
parameters.
When running more than one woofer in a mono configuration we recommend that you
share enclosure space and keep the speakers as close together as possible in the baffle.
This tends to do the most effective job of allowing the speakers to act as a single piston,
moving the optimum amount of air. Do note well that should you decide to operate stereo
bass you MUST run the woofers in separate air chambers. Additionally, if you are running a
complex setup of multiple amplifiers driving multiple coils or speakers you MUST meter the
amplifiers at various levels to ensure the voltages at the coils are equal. Imbalance in this
area will at best cost you SPL and at worst will damage your equipment.

You'll be referring to our data and speaking to our distributors to choose a box design, but
some general information is that a larger box will tend to give more low bass but at the
expense of some power handling. If you are lucky enough to have a large and powerful
amplifier then you will be able to run the subwoofer harder in a more controlled fashion. A
less powerful amplifier always carries with it the risk of burning out the speaker due to
distortion and the resulting excessive heat soak.

Every subwoofer installation needs a crossover function - the precise settings are a subject
of discussion for each particular setup but a good starting point is to work with a 25Hz
subsonic (low pass) filter and a 100Hz high pass filter. Whilst these will not produce
optimum results in every case they will certainly be enough to get you up and running.

Once the speaker is installed and working it is vitally important to follow a break in
procedure. On smaller woofers with single spiders a short break in period of a few hours at
medium volume, making sure the woofer is not in any way stressed, will result in a
satisfactory loosening of the components. On the larger or multi spider products or
specialist professional woofers such as RED series and XPL it is absolutely critical that the
speakers are not extended until at least 20 hours of playing at medium volume has been
completed. Failure to do this will almost certainly lead to failure of the motor due to the
suspension presenting excessive resistance in its pre-break in state. Failure of speakers due
to insufficient running in is not covered by warranty. Please note that TS parameters can
and do change dramatically after break in - until the speaker is at its equilibrium.