Massive sound system coming along.

[jforest1]

Gutted interior:


Gunk--nasty 40 year old floor pan.


After putting a wheel on it for a few hours. Surface is much cleaner now, but much more work ensued.


Painted to protect from future deterioration.


Stinger RoadKill sound dampening material in floor pans.


Sound dampening material in trunk.


Wiring run. Carpet and carpet pad going back in on top of it. Haven't mounted up everything--still in dry-run mode at this point.


Custom speaker box design, took probably 20-30 hours and 4 revisions to make it work. Trunk is big--but short and the hatch is very small by comparison. Box needed to be a fixed size to support the subwoofers, but couldn't do it without leaning the drivers back and splitting the box so that it could be assembled/disassembled IN TRUNK, the design of which was vastly tricky.

For all you CAD wizards out there, I used Inkscape (vector-image editor) to design this (hand edit everything) and if I ever have to design something this complex again, there's no need to sell it to me--I'll probably use a real CAD tool.


Customer designed, assemble-in-the-trunk ported dual 10s subwoofer enclosure.


The trunk setup--dual 10s in a custom box (Polk MM1040s), with a Kicker DX1000.1 mono amp and a Kicker ZX650.4 4-channel amp and Stinger components, power, and signal wire. I have to clean up the wiring over the wheel cover there, but all other wires immediately and cleanly disappear under the carpet.


Phase 1 and 2 are out of the way (just cleaning up now), Phase 3 will be installing a pair of 5.5" Polk speakers in the doors, lower front of window crankarm, and I'll start on that once I find the door boots for the wires from a junk yard.  Thanks for all the help thusfar guys--I've probably posted about 10 different topics and learned a lot since undertaking this one and your advice was critical.

JF

['Cuda Hunter]

That looks really good.  Bet it will sound even better.

Did you mount the box to the trunk floor?

[jforest1]

Yes, via L-brackets.  It's sitting in the bottom of the floor pan, and is too tall to slide forward given the section that comes up over the rear axle, but I have two reinforced L-brackets on the back side (car-front) and a very small one on the right side to keep it from sliding left and right and torquing out the two L-brackets on the back of it.

The amps have L-brackets that are bolted through the floorpan.

I also just got done cleaning and painting that fuel tank filler neck.  Next step (a bit out of order I realize) is to put some piping/liner around the carpet.  I realize now that given how I was installing it, this carpet probably wasn't the best choice, but with this being my first go at this sort of install, live and learn.

JF

[jforest1]

After 6 months or so of mulling over whether or not I should do it, I began last month working on installing the door speakers (added pictures). At this point, I'm just waiting on Polk Audio to send me some longer screws so I can finalize the install.

Took me a lot of psyching up to drill this hole in the door panel--roughly 6 months!


Some Stinger Roadkill sound dampening material on the door panel.


Used a highly specialized 4 3/8" hole saw from Lenox to do the trick. This is the only 4 3/8" hole saw I could find on the internet, matches the Polk MM521 speakers perfectly.


Had to mount the MM521 module on front inside of the door--which is VERY tight. Most painful part is getting the wiring mounts on the inside of the door.


Ran the Stinger 14-gauge OFC wiring through a couple of grommets in the kick panel and into the front of the door. Last time I did this (see the remote mirror boot above it), I had to remove the door. Luckily, I managed to get it this time without having to. But I did destroy a drill bit in the process.


Had to construct an independently mounted particle board spacer ring between the door and the door panel to ensure the speaker is snuggly mounted.


With the door panel back on, here's the finished hole where the 5.5" door speaker will be mounted.


JF

['Cuda Hunter]

Nice!!

It takes a while to just cut up perfectly good parts. 

I bet that system is gonna sound awesome!!

[jforest1]

Used to scoff at mp3 files with anything more than 128kbps bitrate, because audiophiles would claim to hear the difference but I couldn't hear a thing.  Even with just the 10s (MM1040s) and 6x9s (MM691s) I can already hear the difference in quality and clarity. 

Once I get the 5.5" (MM521s) speakers in the doors, I'll have more mid-range sound and it will fill out a bit (currently a bit tinty with a bunch of bass, since the 6x9s have both a 3/4" and 1" tweeter in them each).  With the 5.5" door speakers, I'll be adding I nice cone for mid range and another 1" tweeter up front.

One thing I did notice is the ported dual 10s enclosure is not blasting as much as I had thought/hoped.  It may be due to position, but the 6x9s appear to be driving the bass more than the 10s.  I've got floor of the trunk lined with sound dampener, the port in the enclosure is passenger-side facing and roughly 3/4 width over in the trunk closest to passenger side.  One of the big question marks in my head is the guys at Polk said 2lbs of polyfill, which I could not fit in there unless it was really compressed.  So I tied up a couple of rolls of it, pressed them down as tight as possible, and shoved them in.  Now I've got doubt that they are so tight they aren't letting the air pass through and so instead of simulating a larger volume by heating the air, they are actually lowering the volume of the enclosure. 

Anybody got any experience/recommendations here?

JF

[68-383Bee]

Your 6x9's should not be producing more bass than the subs, so if that is the case, something is wrong.  Was the trunk lid shut or open?   As far as 2 lbs of fill, that seems like a lot and the fact that you rolled it up to stuff in could be contributing as it might be blocking the port.  For ported enclosures, I ususally line the sides with 1" to dampen the standing waves, if I do fill the cavity (sealed enclosure), I would do so very loosely.  Other things to check:
Amplifier working correctly?
If using internal crossover, is it set to LPF?
What is the crossover frequency set to and how does it compare to the port frequency?
Amplifier gains set correctly?
Adequate input voltage to drive the amp?
Subs wired for the correct ohm load for the amplifier?
Port size correct? What was the tuned frequency supposed to be?
Enclosure size correct? What is the internal volume and did you account for speaker displacement, port area, internal bracing, etc?   The details you posted list a lot of the boards as 1/4" and 1/2" and do not show any internal bracing.  If this was built this way it will be a problem as the enclosure will be flexing, resonating, etc.  If it was built with 3/4 MDF, did you account for the increased thickness?   Did you run this box design past Polk tech? I ask as the enclosure seems pretty small to be ported and the large amounts of fill may be a crutch for a poor design.

There are a lot of factors that can contribute to poor bass response and you so have to systematically step thru everything. I tcould be something simple, but I am betting it is the enclosure.   Let me know how it goes and I will try to help. 

[jforest1]

Was the trunk lid shut or open?   

Both

As far as 2 lbs of fill, that seems like a lot and the fact that you rolled it up to stuff in could be contributing as it might be blocking the port.  For ported enclosures, I ususally line the sides with 1" to dampen the standing waves, if I do fill the cavity (sealed enclosure), I would do so very loosely. 

The amount was per Polk box specs and per their suggestions based on internal volume.  I know the position of it is not immediately blocking the port, but given that it is so tight, seems like it is reducing the internal volume rather than simulating an expansion.

Amplifier working correctly?

It is on, the subs are working.  I'll go back and manipulate the gain settings to see if it has a material difference.

If using internal crossover, is it set to LPF?

My head unit has this, and I have LPF set to off.

What is the crossover frequency set to and how does it compare to the port frequency?

80hz.  Need to research what port frequency is...

Amplifier gains set correctly?

Started at 75% max volume on head unit and raised gain until distortion, then backed off.  Did again after a couple weeks of "breaking in" speakers.

Adequate input voltage to drive the amp?

Used 0-gauge Stinger power cable to trunk from battery, splitting it with distribution block to 2x 4-gauge cables into the amps.  About 16 ft of 0-gauge, and 1.5 ft of 4-gauge.

Subs wired for the correct ohm load for the amplifier?

Yes.

Port size correct? What was the tuned frequency supposed to be?

I'll double check, but this was something I worked on for quote some time with Polk technical since I had to customize the box a bit, so I'm assuming the problem isn't here.

Enclosure size correct? What is the internal volume and did you account for speaker displacement, port area, internal bracing, etc?   The details you posted list a lot of the boards as 1/4" and 1/2" and do not show any internal bracing.  If this was built this way it will be a problem as the enclosure will be flexing, resonating, etc.  If it was built with 3/4 MDF, did you account for the increased thickness?   Did you run this box design past Polk tech? I ask as the enclosure seems pretty small to be ported and the large amounts of fill may be a crutch for a poor design.

Yes.  Everywhere there is a 1/2" MDF there is a 1/4" layered on it.  This was because I had to assemble the enclosure in the trunk, so it is 2 pieces with an outer shell.  I don't expect the problem to be due to internal flex (there are actually braces not shown in the diagram), but do mistrust the amount of fill. 

JF

[Gumby]

Years ago I built a box to fit in the trunk of my Grand national. I used a book I bought from radio shack to make sure internal volume was good for the speakers I had, using all the speaker measurements. I made it out of 3/4 MDF, and used liquid nail to glue everything together, and lots of drywall screws. It is a sealed box with one Rockford Fosgate 15" woofer in the center and two JBL 8" tri-axials mounted in there own enclosures on each ends of the box. You really have to experiment with the poly fill a lot, because it can make a HUGE difference in sound. I would test mine on my home Kenwood rack set up. I actually had enough bass to knock pictures off my wall inside the house! lol. I used Dynamat and lined the entire inside of the box. I also took the boxes I built (I made several, the one big one, and three smaller ones - 2 use plain JBL 8" 3 ways, and one uses a Kenwood 6 1/2" component system) to Rhino liner and had them sprayed to make them waterproof. (I would reccomend Line-X or something, RhinoLiner is too bumpy and holds a lot of dirt in) You can see pics at http://s158.photobucket.com/albums/t90/broncobra/ at the end of page 2 and most all of page 3. The large box is too heavy for one person to pick up! lol. The aluminum piece across the top is my amp rack for a couple old school Rockford Fosgates - back when they were made good. I had to replace all the crappy plastic grill mounts with metal ones. The plastic kept breaking. Your box looks good! It should pump out the bass.

[68-383Bee]

I have seen many ported boxes that did not perform well due to enclosure size mistakes and port mistakes.  When you are working with small enclosures such as this, they percentage of loss is much greater with seemingly small changes.  You state that the box has bracing that can't be seen. Was this taken into account? 

I roughly checked the print you posted and I show that the enclosure is about 1.56 cu. ft. assuming 75 cu. in. per woofer displacement.   The port area is 27cu. in. by 17.25L which has a tuned frequency of 46.5Hz in the 1.56 cu ft enclosure. Remember that you cannot count the port area as part of the enclosure volume.   If we assume that 20% of the enclosure volume has been lost to internal bracing and "system effect" (unmeasurable things that effect the performance such as dense fill, etc) the volume is reduced to 1.25 cu ft and the port frequency climbs to 52HZ.  FYI, for a general purpose box (rock, light rap), I would like to see the frequency around 40HZ and with max of 50Hz for "boomy" rap music.  Remember that ALL audible music rolls off sharply below the port frequency.  With your crossover set at 80 HZ, and the port potentially tuned above 50HZ, you really need to find the "right" music to have this box perform.  Your output may seem low based on the frequencies being played so try some different types of music.  A quick check of your port frequency can be made by plugging the output of a signal generator into the amp. When you sweep the frequencies it will get noticeably louder at the tuned frequency and then audible output will fall off as you go below it.  If you don't have access to a generator, search the internet for some sine wave mp3 files (40HZ, 45 HZ, 50Hz, 55HZ), burn them to a CD and play them.  Note that below the port frequency is where damage will occur to the speaker so do not play it loud or long term at this point.  In fact once you find this point, you would be well off installing a piece of equipment (plug for AudioControl devices!) that has a low frequency subsonic filter or a adjustable Q control to kill these frequencies before they get to the amp.

Curiously enough, I checked Polks Website and they seem to indicate a 2.06 cu ft box tuned to 40Hz for these speakers.  For a Sealed box, they recommend .66 cu ft each or 1.32 cu ft for the pair which is much closer to what you have.  While I understand the desire to run a ported box, I have a feeling that you would be much happier with a sealed box in this installation.  I went through this with my own car and I ended up with (2) 1.0 cu ft boxes that I managed to squeeze in over the shock crossmember and preserve most of my trunk space.  The box fits into the trunk fully assembled and while my speakers and amps are much different, I think if you heard it you would be impressed enough to change yours. I don't want to hijack your thread, but let me know if you ever decide to change it and I can post a drawing of my box.
 

[jforest1]

Door speakers in!



Now just gotta get back into that sub box and figure it out.

JF

[Gumby]

jforest1, is that toggle mounted on the right side of your dash a remote mirror control?

[johannes]

jforest1.
Thanks for sharing your installation with us.
Many of us either HAVE a sound system (and consider upgrades), or WISHED we have one (on a few occations atleast)....

Q1. I'm sure you gave this a lot of thought,...please share with us why you choosed installing the speakers in the doors instead of in the kicker panels...

I've seen a few decent looking kicker panel installations where the speakers are "tilted" backwards...but haven't got the slightest info on how the sound will compare ...

Any one else got any thoughts on this issue ??

2'nd question; I see you've put sound deadener to the inside of the door skins..... will the steel door itself also "need" some deadener?....any space issues??....and did the road noize change much?

[4Cruizn]

WOW that is looking awesome.       Nice job!