This page was created as a
guide to assist you in the installation of your kit. This page is meant to
be accessed by those who have supported Subthump by purchasing a kit from
us. Those who wish not to support us, can find their own
methods. With that in mind, we ask that
you do not display the link to this page in a public
forum. We are active on most forums and if we see the link
to this page posted, we will either change the link or delete this page
altogether. Thank you.
To begin installation
of your kit, locate your factory amp which is hidden behind the moulded carpet
on the back wall of the trunk on the driver's side.
If you plan to mount your aftermarket amp elsewhere, you can leave the
factory Boston amp in place and just unplug the 3 harness connectors that
connect to it. However, if you plan to use this factory spot, you will
need to remove the amp. Remember the spot is very small and only a few
amps will fit here. We do offer a nice mount that goes here if you find an
amp or processor that will fit, item 5G-FFA on our website. If you decide
to remove the amp, use a 10mm wrench, loosen and remove the nut and the
Boston amp will pull up off the stud and out of it's holding tabs. With
the amp removed from it's mount, you will notice that the main audio harness is
split into 3 sections. The connector at the top is called the x1
connector. This is mostly used to power your factory amp, but the power
wire is really too small for a good aftermarket amp so it will not be
used. The middle connector is the x2. This harness contains almost
all of the speaker wires that lead out to all your speakers. The only
exception would be the wires for the midrange section of the rear 6x9s, which
are part of the x1 harness. More on this later. The bottom connector is
the the x3. X3 is simply the input harness. Which means the 4
channel pre-amp signals coming straight from the radio.
The X3 RCA Harness Resistor Installation
Our kit is relatively simple. Use our x3 harness
(harness with brown connectors) to connect to the car's x3 connector. This
will give you 4 channel RCA's that you can plug your rca cables into for your
input signal. Before you install the x3 harness,
there is one step that you will need to perform to the X3 (brown) harness.
It is detailed in the following video. Please follow it carefully.
The resistor is included in your kit and is taped to the back side of the paper
that you found this web address printed on.
Please note that this step is not mandatory and will not harm anything if you
don't install the resistor. The only function the resistor serves is to
trick the radio into thinking that the factory amp is still
connected. On some cars when the factory amp is unhooked, the radio
behaves very differently. For instance, the chime and blinker volumes
can get really loud and some speakers may not work. The resistor simply
applies a load to the amp control wire (orange) to make the radio behave
normally. As said, we have found that many cars don't require the resistor
so you may decide to skip that step to save yourself some time. However,
if you skip the resistor installation and experience any of the symptoms
above, then you definitely need to hook up the resistor in your
kit. You can use any ground in the car desired when connecting the
Next, run your rca cables and connect them from the x3 harness to your
amp. Please note that our harness uses the signal straight from the
radio. When you fire your system up for the first time, if you hear any
strange sounds or your amp goes into protect mode, this means your amp doesn't
like the dc voltage that is in the system. What you need to do is get two
of our nr16 ground loop isolators. These plug into the x3 harness and then
your rca cables plug into it, and it eliminates the ground loop. Most amps
will not need this, but we have experience a few that do and so we want you to
know what to do in that instance so you don't panic.
The white wire
with the orange stripe on the x3 harness is your turn-on lead. Wire this
to your amp's remote terminal.
that you DO need to run power and ground to your amp. The x3
harness will not power up your amp alone.
The X2 Harness
The x2 harness (harness with green connector)
connects to your amps speaker outputs. The wires are coded EIA standard
and are also labeled to ensure you hook each wire to the proper output channel
on your amp. Solid wires are
positive, striped wires are negative. The x2 harness comes with 12" of
wire. If you need more reach, simply use some 16 ga. speaker wire as an
extension. Just be sure you get them wired correctly. We take no
responsible for any blown speakers or shorted out amps. Once the x2
harness is wired up, it will snap onto the x2 connector of your car's audio
The X2A Jumpers (needed on coupe, not
used on convertible)
The last thing involved is installing our x2a
speaker jumper wires (harnesses with gray connectors). To install these,
All you do is unplug each rear 6x9 (at the speaker) and install the x2a (short
gray harness) In-Line. That's it Done.
The rear Boston 6x9s are bi-amp'd meaning the
tweeter and midrange are powered by 2 sets of speaker wires and two channels on
the factory amp, not one. Since a 4 channel amp only has two channels
available for the rear, we have two options. Either power a single portion
of each rear speaker or split the signal and power them both. Earlier
versions of the X2A only powered the midrange of each rear 6x9. Further
develpment of our of the x2a harnesses (v3.0) allows us to power both the
tweeter and midrange of each rear speaker and this is a huge improvement.
The power is split at the connector and a small capacitor is installed in the
tweeter line to filter out unwanted bass. This makes for a full range
speaker set--just like most aftermarket speakers. If you later decide to
install aftermarket 6x9 rear speakers, you can simply snip off the ends of each
harness and hardwire it to the new speaker using the gray
wires. This way you will not have to cut the factory harness to
install new speakers.
Troubleshooting.. Please read this section
thoroughly before asking the following questions.
The main thing is don't panic if something is not quite right when you first
attempt to fire it up. Even though this is a simple kit, one missed step
can be the difference between getting it to work or not. There are
many variables in an install so be sure to check over all your steps.
Again, when you fire your system up for the first time, if you hear any
strange sounds or your amp goes into protect mode, this means your amp doesn't
like the dc voltage that is in the system. What you need to do is shut the
system off and get two of our nr16 ground loop isolators or any good line out
converters (not scosche).
Also if you fire it up and the chime is
much louder than your music or only one door speake works, then you need to
revisit the section on performing the x3 conversion and how to hook it up
Remember, Gains are Key. The chime, onstar and other
warning sounds in the car are heavily dependent on the gain settings on your
aftermarket amp. Higher gains mean more power to your speakers, but the
trade-off is louder chime and onstar voice. So turn your gains
up to levels that you are comfortable with and stop. High gains are
not required to get improved sound quality and output. Actually, very
minimal gains are all that's needed. During our trials, no more than 1/4
the way up was plenty. This is a 6v system so it pushes plenty signal to
If everything works except your backup warning signals, please note that the
backup sensors are a high frequency signals from the rear channels on the
radio. If you set your crossovers on your amp to filter that frequency
out, then they will not be audible. So changing your crossover settings
should bring them in.
If you shut your system down and experience any thump or other strange
noises, this is actually quite normal and expected to a certain point,
but varies greatly from amp to amp. It can be more pronounced with some
amps and a non factor in others. It just depends on the power supplies
that are used by your amp. If you have your gain settins up too high, it
can make it worse, so keeping your gains down really helps diminish the sound if
you have it. Also using our ground loop isolator on the
subwoofer rca set is also highly recommended. p/n NR16. This will
eliminate the turn-off thump completely.
Static. If you have static, then you probably have a rca cable running
near the power cable for the amp. Try re-routing these so they are not
right next to one another or using shielded rca lines. Also, we have found
that digital amps tend to have static caused by interference with the radio
antenna that is imbedded in the back window glass. So it is best to stay
away from digital amps altogether.
If you have any further contributions, please let us know and we will post it
here for the benefit of others.