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Tower
Speaker System II
I originally built a 4-speaker box for my tower
2 years ago and life was good. Eventually I realized that I wanted
more...don't we all. I had some new goals though and they were derived
from the limitations and flaws and dislikes of the first box. The
first box was great. It was loud, clean and simple. I felt though
that the disspersement was lacking. It had a very narrow projection
range. The only way to resolve this was to add additional speakers
(6 in total) to help fill this void and create more sound, not louder
but just more in total. So I defined some basic goals and began
planning. While this box was more planned then the first box, I
still had to wing-it on a few things.
Tower Speaker Box build:
I set out to build a new Tower system to compensate for the issues
I had with the old one, mainly volume, clarity and looks and a few
design flaws to boot. While I still raise the hairs on the back
of my neck when I power it up and let the tunes fly, I have much
larger sense of accomplishment with this box, as it is totally custom,
exactly what I wanted and more then I expected from my own hands.
The basic approach I took with this project was, "do it right
the first time". Plan and then think. Investigate and think
again to ensure that I didn't have to go backwards to go forward.
Many people refer to this as "execution". The old adage
"measure twice cut once" sort of thing.
Picking the speakers was easy. I already had 4 JL Audio TR650-CX's,
so I only needed 2 more. These are the middle-of-the-road line for
JL. I made the choice based on the environment they would be in.
I board 99% of the time in Salt water. I couldn't justify the higher
priced JL speakers in salt water, and the possibility of salt spray
and general abuse they would receive. The cones are Polypropylene
and have Butyl rubber surrounds which hold up better than the foam
surrounds in water type environments as well.
Powering the box was an easy choice. I already had one 4-channel
Coustic321Q, so all I did was purchase another…thank you Ebay!
They offer the speakers 40watts per channel. While these are not
considered the best amps on the market, they are surely not a beginner
grade either. They produce clean wattage, low distortion and are
easy to setup. Other features that helped the decision were built
in X-over's and ability to run 40watts RMS at 12.5 volts, great
for the boat environment. They have been nothing but awesome in
my opinion. I have used all types of amps in the past, from PPI,
to Alpine and even Xtant, and so far I have had the great success
from the Coustics. If you are looking for a reliable, inexpensive
amp with high-end features, I encourage you to check them out. I
am sure you will be as please as I have. With the speakers and power
issues out of the way I set out to build the box!
Building the box…
I made the decision to go with a full box that would hang from
the underside of the tower. By using a box enclosure I was able
to give the speakers the correct amount of air-space based on manufacturers
specs. This is a crucial step to getting the speaker to perform
the way they were designed by the manufacturer, especially in the
open-air environment that they would be residing in. Using the original
specs from the first box, I added the two new speakers to get the
total width required. A massive 46" wide, 12" deep and
9" high. Yes it is huge and the final weight shows. I then
measured the tower and got the maximum dimensions that I could work
with in the interior of the tower…plenty of room. It was at
this point that I realized the overall magnitude of the project
and that I would not be able to do this all where the boat was...155
miles away in S. Jersey. I decided that the only thing I could do
was to build a mock-up of the tower to take back to my shop in North.
Jersey.
I built the mock up using PVC and wood. I measured the tower about
10 times then literally took it off the boat and brought it into
the garage for additional measuring. I finally built the mockup
and was able to take it back with me knowing that I could build
the box to match the tower exactly.
I then began to draw out the box on paper till I got an acceptable
size, shape and overall look. I started to look at the available
boxes on the market. None of course were what I wanted but they
were a great source of design elements and ideas.
I determined that I wanted...
· 6 Speakers
· Aerodynamic with lines that flow with the boat.
· SAFE/Structurally sound enough to hold a person of 150lbs
off of it.
Yea that last one sounds a little extreme, but this is the way I
work. While I don't have a physics degree, I do understand engineering
and forces. The sheer weight of this box with the speakers is far
heavier than I expected, but hit a double-up with a poorly designed
box...and you have a concussion. Not a risk I was willing to take.
For material, I started with 3/4" MDF. This is an inexpensive
and very dense wood material. (It should be mentioned that this
construction material is heavy! My speaker box weighs in about 45lbs
w/speakers). Dense building material is crucial to help reduce enclosure
vibrations. The more an enclosure vibrates, the more it will degrade
the sound of the speaker, and overall performance. Once the speaker
face was cut and rough shaped, I set out to design a metal frame
system in which the brackets that attach the box to the tower would
be mounted. The frame system would be integrated into the box as
the initial layer. It was designed out of 1/8th inch aluminum flat
and angle pieces. I used nylon fitted nuts and oversized sheet metal
screws to handle the rest.
Why would anyone go to such lengths when your gonna eventually
be drilling and mounting brackets thru nearly 1" of fiberglass
matting and fleece??? Mainly because I have a habit of "over-building"
everything I do, but secondly and more importantly, I don't want
it falling on anyone should the box prove not to be as strong as
originally intended. Right now this system is so strong, that I
can actually hang all 175lbs of myself off of the box. This is a
feature I am really proud of, but of course caused the biggest headaches
in the overall design, and took nearly two full days to design build.
During the build of the frame, I continually referred to the "tower
mock-up" I had built. Size, shape and integrity, as well as
overall implementation to the design was addressed. That's why it
took two days. Honestly the pics don't do justice to internal frame
of the box. It may seem that I am bragging a bit, but every detail
was covered twice, and I would fully trust this box in any water
condiction, something I am sorry to say most cannot brag about.
Once the framing was complete I sanded and finished the shaping
of the front of the box (which is actually the face that the speakers
mount to). With that complete, I pulled out the fleece and began
wrapping the frame front to back. I tucked and pulled till I got
the overall shape that I wanted that I felt was also athstedically
pleasing. It was at this point I realized a mistake, that actually
worked to my advantage.
While pulling the fleece tight, I actually curved the speaker face
a bit. While it is not a huge curve, it does help to arch the speakers
a bit, enough to help create some additional disspersment, with
was a suedo goal. A few of the pics show this arch, and while is
was an accident, I appreciated it.
In the design of the framing, I used a center divider that helped
stiffen up the speaker face of the box. This helped divide the side
so that I could run 3 speakers on each side, but still allowing
them to share a common airspace. By having the 3 speakers share
the airspace I was able to incorporate a technique they call "Acoustic
Coupling". (Acoustic Coupling in a nutshell is when you place
2 or more speakers in a common chamber on the same face/side. When
the music plays, the speakers internally connect or couple together
and become one regardless of minor signal and wattage differences.)
This setup also allowed me to run this box like the first one, which
was in stereo. The 3 left speakers play left signals, and opposite
for the right. Minor issues resolved and I was moving on! The center
support actually helped create a design aspect that turned out pretty
cool in my opinion. You can see it in the pics. It looks like something
is trying to bust out of the box toward the boat just below the
speakers.
Back to the fleece…I began to paint the fleece with fiberglass
resin. Fleece is great because it absorbs a lot of resin. I have
found that once you measure out the amount of resin you THINK you
need, double it, and that should be enough for fleece. Felt works
equally as well, but only requires about 1/4 more resin.
Let the buildup begin...
With the fleece now dry, the shape of the box was beginning to
show. I was lucky in that I didn't have to fix too much after the
initial fiber glassing so I was able to move forward rather quickly.
I just busted out a bunch of felt and fiberglass matte and started
laying it down. I dropped 2 full layers of felt, then roughly 3
layers of fiberglass matte over the entire box except for the speaker
face. It was finally starting to take shape, but the hardest work
was still ahead. I really thickened up on the last layer of matte
to help smooth out the surfaces in preparation for the bondo. The
smoother the last layer is, the less work you'll have to do later,
which unfortunately for me there was going to be a lot of in the
coming days.
Once everything dried (which took nearly a day due to the heavy
rains and high humidity we had during May 2003) I got started on
the bondo. Overall I used 1gallon of bondo to get everything I wanted.
Sounds like a lot, but I was flying by the seat of my pants here,
and a lot of the bondo was sanded down to nearly nothing, so it
was probably more like a 1/4 gal of bondo that is actually in the
entire box.
Working with bondo is like nothing I can comprehend. It just stinks
(no pun intended). I was not initially prepared for it. The dust
bondo puts off is this fine powder-like, pink colored aggravation!
What I suggest for anyone that is going to work with it is...
· a compressor with blow nozzle to remove the dust from the
surface your working on
· a HIGH quality dust mask
· quality eye protection that seals your eyes, ski goggles
work well for this 4, latex gloves to keep the dust from drying
out your hands. Overall I spent about 22hours hand sanding the box
to get the final shaping and overall look that I envisioned.
With the exterior complete…sorta, I began working on the
interior of the box to finish it up and could move on to the painting.
I cut the holes for the speakers and smoothed everything out. I
next added an additional 3 layers of fiberglass to the interior
to stiffen up the larger areas. I sealed up any other areas that
needed it and let dry.
The interior of the box received a layer of Dynamat and then a
generous layer of vehicle undercoating. This would ensue that everything
was sealed and dampened as good as possible. It also helped further
reduce vibrations on the walls of the enclosure. I will eventually
add Poly-fill (the stuff you fill pillows with) before I mount the
speakers. This helps in reducing the standing waves in the interior
of the box, but also to give the speaker the illusion that it is
in a bigger box (a trick I learned in Car-Audio Competitions, and
a trick they use very often in Sub-Woofer boxes, but works equally
well for smaller speakers). The poly-fill also helps the speaker
play lower freq's without sacrificing sound quality.
With the interior and exterior pretty much done, I let the box
sit in the sun for 2 full days. I wanted to make sure that everything
was dry before the first layer of primer went on. I smoothed out
the outside between layers of primer. A total of about 8 layers
of primer went on till I got the result I was looking for. I finished
my final sanding with 1000grit and was ready to paint.
Painting is not my strong point, but how hard could it be? Well
that was answered when I decided to put down the first layer of
paint inside the shop on a rainy day...big mistake. With limited
ventilation, and humidity at about 95%, it spelled headache &
paint that didn't dry for another 2 full days. 1 Day of sitting,
and 1 day in the sun to bake. From then on I only painted in the
sun, letting everything bake in. I honestly don't know how many
coats of paint are on there, but I used an automotive paint with
flecks built into it. I probably used about 8 cans of paint for
about 4 full layers after wet sanding and fixing the little imperfections.
After that I used 3 coats of clear to finalize it, and let that
sit for 2 full days in the sun.
My trick for holding the box and being able to paint all the sides
at the same time was to use some long pieces of 2" wood that
I could insert into the interior of the box and clamp Up using a
clamping workstation. The pics show this very clearly and I hope
my idea can help others in their projects similar to this.
Wiring the Box…
Ahhh, one of the jobs I love and hate most about audio systems,
but is a crucial part.
For any system that I have ever done, size 12ga. wire for speakers
up to 8" is the only thing that will do. Subs always get 8ga.
Power and ground as needed based on wattage. These are just some
general rules that I follow.
My first box had a set of wires coming out of it, and then down
the outside of the tower and down tot he amp. This was all run in
wire loom I painted silver to match the tower. I decided that this
time around I WOULD run the wires thru the tower. My goal was to
be able to take both the box and the tower off the boat and not
have to worry about the wiring. I do on occasion have to take the
tower off for storage, maintenance and such. To ensure that the
tower could still come off with out a problem, I used wire-loom
from the point that the tower folds forward down to the hull and
over to the vent just under the windshield. They run alongside the
lower mounting of the tower in wire loom spray painted silver so
as not to stick out like a sore thumb. I ran a set of wires from
the amps thru the factory vent tube just under the windshield on
the pass side.
Running the wire thru the tower was pretty east. The first run
of wire thru the tower was actually string. I then used a vacuum
to suck the string thru the other end. I whipped together the 6
sets of speaker wire and tied it to the string. My buddy Ryan began
pulling and I started to feed the wires thru. A little soapy water
helped in the sticky spots. With that complete, on to the connectors.
The wires for the box are connected and pinched to the speakers
internally. They are caulked as they leave the box to keep everything
sealed. I then routed out some plastic blocks on the milling machine
and set in the connectors. This provides a solid mounting for the
connectors and ensure that if anyone were to pull the connectors
out wrong, they would only pull off from the wires on the tower,
and not mess with the box itself making fixing the repair easy.
I board in salt, and it eats even the highest-grade connector plugs.
What to do...What to do...Use the cheapest plugs available. Go to
Radio Shack! If the connectors were to have a problem, they are
cheap and can be replaced fairly easily.
Attaching the box to the tower…
This step could not be easier seeing that I originally set the
box up based on the mock-up of the tower. The clamps are from http://www.centerstagelighting.com/.
They are really designed for lighting fixtures. Made of aluminum
they were designed to handle about 100lbs each. With 4 clamps I
think I have things covered. Check out the website for additional
information.
Boat system & Tower amp…
My boats current system is all Clarion. CD player, Amp, Speakers
and Sub. A 4 channel Clarion amp powers the boat. 25x4 uses two
channels for the boat speakers and 2 channels bridged for the sub.
The sub is a Clarion 10" while the others are clarion 6.5"
co-ax's (4), two in the bow, and two in the back. It uses the Clarion
Marine HU, which works well, considering it uses the lower end components
from Clarion.
I divided the HU fade to run the boat off the front channel, and
the tower off the back channel. I adjust more toward the back when
boarding to keep the volume down for the passengers. If your sitting
in the back though, tower box can be a bit loud, but most don't
mind!
Again for the Tower speakers I used 2 Coustic amps. They are 40x4
units. I only needed 6 channels so I used the other remaining channels
for the Subs. This setup will gave me a non-fading sub setup and
run about 200 watts to the subs @ 4ohms. Each speaker in the tower
has a dedicated channel, all crossed over using the amp's internal
x-over @ about 70hz.
I ran 2 additional power wires (4ga.) from my second battery straight
to the amps. I used the 12V ignition trip from the Clarion HU with
a 30amp relay. I borrowed the Ground from the clarion amp for the
Coustic amps thru a distribution block. I ran another set of RCA's
from the HU to the Coustic, and mounted the amp next to the Clarion
in the storage compartment on the pass side of the boat. This is
a protected area and still gets good ventilation. I ran a jumper
RCA from the output of 1 Coustic amp to the other to help in reducing
the clutter of RCA's.
The Result…
This box screams and is also very clear. With the addition of the
2 speakers it really rounded out the sound. It echoes's off the
houses that border the channel we ride in, and I am sure that a
few comments have been made.
All in all it works great, and I highly ENCOURAGE anyone willing
to spend the time to set yourself up with a Tower system, you won't
believe you lived without one for so long.
Additional notes on the project:
- Take your time! Overall it took about 6 weeks for me to finish
this box. Granted I was laid off from work at the time, but I took
over a wek just to paint, and was only working about 4-5 hours per
day, 5 days a week. This will come together but be patient and do
it right the first time and you'll be happier with the results.
- Get the right materials and tools for the job. I have an assortment
of air tools that helped. Air drills, cutting wheels and Rasps on
the cutting wheel tool really help save on the elbow work.
In a few recent emails, a fellow wakeboarder asked me about the
pictures I have posted on the site. I felt they were great questions
and help go into further detail on certain procedures. I have included
them:
Question:
When you did the resining, did you put any fiberglass mat or woven
material down during the first resin application?
Answer:
no, I just resined the fleece. It was the basic fleece you get at
the fabric store, nothing fancy, just the cheapy stuff.
Question:
What did you use on the subsequent layers of resin application and
what was the weight of the material.
Answer:
I cut up different lengths of felt (kinda thick Arts & Crafts
type felt), and mixed up a quart of resin/catalyst and just went
to town till I ran out of resin or felt. Then I repeated this till
the larger sections of the box started to get strong. (Once it dries,
try pressing into the large un-supported areas to see what is weak,
then scribe it with a nail to mark it for the next batch of glassing).
Repeat till those spots Solid!!! Then just drop a few layers of
the chop matte on top and glass over. Yea its gonna be a lot of
work, but the frame design and prep with the fleece it where it
really gets the shape from, if you don't like what you have, don't
start glassing yet, redo the frame and fleece. I may not have mentioned,
when you stretch the fleece, you then staple gun it into place.
Once the resin soaks thru, it will bond with frame, and hold, that
is the importance of soaking the first layer and creating that bond.
Then you can take the staples out and sand down.
back to where I was...If you don't like the shape, pull the staples
and start over. Once you glass, you could end up having to do the
frame and fleece all over again, as they almost become one with
the resin.
I would recommend that you use Chopped Fiberglass Matte over the
woven matte. The woven is good for strength, but is thin and does
NOT create the thickness or volume you need to buildup. I would
guess it takes about 3 layers of woven, to 1 good layer of Chopped.
It costs more too, and we don't need any additional costs do we!!!.
Don't worry about smoothing everything out with the resin or matte.
While it will cut some time the better job that you do on it, you
will eventually cut down the high spots with a sander (preferably
a belt sander with 60-80grit) and then bondo over everything, which
is the final layer. This is where time and care should be taken
to get the best results the first time. I can't stress enough how
messy that pink dust is (I blew pink snot for a week, the wife was
impressed!). Use a respirator, and if you have a source of pressurized
air, use it to your advantage to blow the dust away from the box.
you can also wipe down the down with a wet cloth or paper towel.
Just a few minutes to dry.
oh yea, again 60/80 grit is great for the knock-down, but after
that, go 100 > 150 > 300 > 400 and primer then 600 grit.
That should make a plenty smooth finish. If you feel like wet-sanding
with 2kgrit, go ahead, but most of that auto paint dries almost
as smooth as glass. (remember I get a little "over-methodical
sometimes) 80 > 150 > 300 > 600 should honestly be about
right in 99% of the cases.
Question:
You mentioned fleece and felt in your explanation. Did you initially
put fleece down stretched it and attached it to the structure, layed
up resin and then put 1 layer of felt, resined it and then another
layer of felt? Why not fleece/fleece/fleece? What is the basic diff
between fleece and felt?
Answer:
yes that is exactly how I did it. Honestly I ran out of fleece.
I was doing a sub box at the same time for a friend, and didn't
realize I was running out. Turns out, it may have been a good thing.
I think the felt was a little easier to work with, gives the same
effect and doesn't take as much resin to soak it. it's a little
more forgiving, I am glad of the mistake, worked out for the better.
Think of the fleece as the concrete foundation, then you use lighter
materials for the rest. The felt dried with a smoother finish too!
Click
HERE the photos
- KG
Links
www.centerstagelighting.com - Clamps
www.radioshack.com - electrical and accessories
www.boatersworld.com - electrical, fiberglass & other boating
supplies
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