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Alpine Install on 7th Gen Accord

post #1 of 9
Thread Starter 
I've posted this elsewhere but I just now realized that AVSForum has a car audio section.


Hello fellow audiophiles. I've decided to create this thread in hopes that it will help anyone that has been considering upgrading their stock system but want to keep the stock look and get the most from the stock headunit without spending an outrageous amount of money. I have seen the options available for mounting an aftermarket HU and unfortunately I do not like either. The emphasis of the system I have decided to build is more on Sound Quality (SQ) and not of Sound Pressure Level (SPL). There is obviously going to be some compromise in sound quality due to the use of the stock headunit and some of the component selection will reflect this (will go into more detail when needed).

This thread will consist of 3 sections. The first section, is a list of system components including the purchase prices and place of purchase. This will help give anyone that has thought of doing this an idea of all the costs involved. The second section will outline the build of the box including subwoofer and amplifier placement. Finally, the third section will outline how I have decided to run main power, speaker wire, signal wire, and cabin speaker replacement. I WILL be replacing the stock tweeters and using the original locations.

The outcome will be what appears to be a completely stock system... until you turn it on.
post #2 of 9
Thread Starter 

I ordered all of the components for my setup over the past two weeks. I have received everything except the felt/carpet that will be used to cover the box. Here are a few pictures of the components that will be used in my setup. Higher resolution pics and close-ups of pics are available. If requested, I'll post them as a reply.

Main Components:

Wiring and Misc:


From Left to Right
4AWG BATT : 4AWG GND : 10AWG SUB Twisted Pair : 16AWG SPKR Twisted Pair

All items were purchased brand new so these are prices that anyone can get... they're not some deals I got on used equipment. All items purchased from ebay were with 'Buy It Now'. Prices paid include shipping and taxes:

JL Audio Cleansweep [CL441DSP] - eBay - $189.95
Alpine 10" Type R 500W-RMS Sub [SWR-1042D] - eBay - $106.99
Alpine 500W-RMSx1 @ 2Ohm Amp [MRP-M500] - eBay - $159.26
Alpine 50W-RMSx4 @ 4Ohm Amp [MRP-F300] - eBay - $149.75
Alpine 6.5" 80W-RMS Components [SPS-600C] - eBay - $77.77
Peripheral RCA Attenuator [PRC1] - eBay - $15.15
KnuKoneptz Karma 16AWG Twisted Speaker Wire 100' - eBay - $43.98
Subwoofer Enclosure Screw Terminals (2) - eBay - $10.98
Total eBay purchases: $753.83

The following order was placed at Darvex.com and I will include individual prices and a total tax and shipping cost for the order:

20' Stinger 4AWG HPM-Series Gray Power Wire [SHW14G] - $32.00
5' Stinger 4AWG HPM-Series Clear Power Wire [SHW14C] - $8.00
Stinger Shoc-Krome ANL 60Amp Fuse [SPF5260] - $5.98
Stinger Inline ANL Fuseholder [SPD5201] - $10.95
Stinger Tee Distribution Block [SPD511] (2) - $21.90
Stinger 4AWG Ring Terminals [SPT5104] - $5.50
5' Stinger 10AWG Twisted Speaker Wire [SHW510BC] - $6.75
Stinger HPM 1-Series 17' RCA Cables [SHI2117] (3) - $64.20
Stinger HPM 1-Series 3' RCA Cables [SHI213] (2) - $21.86
4AWG Firewall Grommet [PG12] - $5.50
Shipping - $7.61
Online Coupon - ($8.06)
Darvex Total Cost - $182.19

The following items were purchased locally at Lowes for the Box Build:

4'x8' 3/4" MDF - $27.48
11Oz Can of high performance spray adhesive - $6.48
1lb 1-1/4" Wood Screws - $8.69
16oz Elmers carpenter wood glue - $3.87
Total Lowes including tax - $49.31

Box Carpet (3' x 7'): $27.36

Total cost: $1,012.69

I admit I may have gone a bit overboard on the wiring. I certainly could have gotten away with lesser quality and cheaper RCA cables and speaker wire, but I didnt want any regrets after installing the wire because it would be a lot of work to replace them if after the install I was unhappy. I chose the HPM 1-Series RCA cables because they are both twisted pair and shielded. This will help prevent any noise/cross-talk from entering the system. I also chose the power wire that I did because it is UNBELIEVABLY flexible and will be extremely easy to work with. As far as the components I selected, I was originally looking at getting the Focal Polyglass comps. After speaking with a local Focal dealer he advised me that I would likely not reap all of the benefits of these speakers due to the fact that I'd be using the stock HU. With his advise, I decided to make a matched system and get the Alpine Components. I've also read that they have a fairly flat response and are really a great buy for the price. Missing from this list is the felt/carpet which I will pick up on friday. Box construction will begin Saturday.
post #3 of 9
Thread Starter 


I started building the box with the enclosure for the subwoofer. I went with the sealed enclosure over the ported for two reasons. The first reason is that I'm trying to keep as much trunk space as possible and keep the spare tire easily accessible. The second reason is because the sealed enclosure will give much more accurate bass response and the drop off is much slower than with a ported enclosure (ported enclosures have more of a sweet spot and anything outside this sweet spot is considerably less audible). I decided that I would build the box to the exact specs outlined in the Alpine manual as the 'Optimum Sealed Enclosure' which is a net 0.6 cuft and 11.5x11.5x12.75. After I built the sealed subwoofer enclosure, I began building the amplifier mounts and aesthetics around it. For those interested in building their own box, I would highly suggest pre-drilling any holes that will be screwed because the MDF WILL split if you don't. Also, any imperfections and small gaps where the walls of the enclosure meet can be sealed airtight with wood glue. I applied wood glue to each edge prior to screwing them together and also along all interior edges of the enclosure.

More to come... I'll be carpeting the box and providing some tips on how to do so early in the week.

I want to point out that the two pieces at the top in the pic below do not actually make up the top of the sealed sub enclosure. There was another piece the fit inside the box that was put in place and sealed first (you can see the screws for this at the top of the sub enclosure). The two amplifier mounts were then put on top of THAT piece and screwed and heavily glued in place. With the glue, its as if it were one solid piece.

The entire setup is 12.75" deep and is 36" wide at the top and 32" wide at the bottom. For two amps and a sub it is a bit of a tight fit but I laid it out so that it will only occupy the area from the spare tire hinge and back, which for those that do not have a gen 7 is the area in the back of the trunk where it is much narrower for about a foot depth. This will keep the large majority of the useful area of my trunk

Also, wood glue has been my best friend when building this box. It helped to seal any imperfections to keep the subwoofer enclosure air tight but it also helped in areas where I could not use screws to avoid piercing the sealed enclosure. Screws were used when possible but also keep in mind that most wood glues available now will create a bond that is stronger than the wood it is holding together.

I picked up the carpet today and it is a bit thicker than the felt-like carpet that I had used about 8 years ago. The carpeting that I used to use was thinner and didnt have the harder surface on one side like this stuff. The result was a carpet that could be very easily stretched a bit a shaped so that you could never tell were any seams were. This stuff I picked up today is a bit thicker and more rigid. I will not be able to stretch and shape this carpet as well and unfortunately, i'll probably be able to see a bit of a seam. I will just have to make do and put any seams in places that will not be noticeable once it is in the trunk.

Plenty trunk space

I wanted a nice snug fit, and I got one... the only problem is there is a curve at the two edges of the trunk and the top of the box meets this when pushing it toward the back. If I would have made the angled cuts at the top a little deeper or made the top of the box 1/2" narrower then this would have cleared completely and I could have pushed it all the way back. With it like it is, I'm only missing out on pushing the box back maybe another inch so it isnt too big of a deal.
post #4 of 9
Thread Starter 

Wow i'm sore. I started on this friday afternoon, mostly mounting the distrubution blocks to the back of the box, mounting the cleansweep, and wiring between the two amps. Saturday I pulled the center console apart, pulled the rear seat, pulled the side and kick panels, mounted the fuse under the hood and ran the power and connected the ground wire, cut the stock HU wiring connectors and began soldering and running my signal wires to the cleansweep. This took quite a bit longer than I thought. I worked (by myself) from about 11AM till about 7PM on this. Then today (Sunday from about 10AM-4PM) I finished running the signal wires, ran the speaker wires from the amps up to the front speakers, pulled the doors apart and replaced the 6.5's and dynamated them, ran the RCA's and control knobs, and finally I put the seats and all plastic pieces and center console back together. Still to do is to replace the tweeters, connect the rear speakers, and dial in the amps to appropriate levels and set the crossovers. Right now, I believe I have the sub crossed at 150Hz and the full range speakers crossed at 80Hz I think. I think I want to adjust this just a bit to cut off a little more bass to the fullrange speakers to prevent distortion at high volumes. Generally I wouldnt cross the door speakers so high but the 10" is really tight, does a really good job at reproducing the higher bass frequencies (100+ Hz), and is quite accurate. When set to the appropriate level, it blends seamlessly. A few times, I actually had to turn it completely down just to make sure that it was actually the sub producing the low end and not the door speakers! So far the system sounds great. I've had to turn the treble up to about +4 to keep up with the replaced 6.5's but I think this will change once I replace the tweeters. lol I will post more opinions and information once i've replaced the tweeters, dial everything in, and let it all break in a bit. I also need to make a piece for the sub box that spans the width for the front to prop it up just a bit. Unfortunatly, the back of the trunk sloped down a bit so the sub faces down a bit as well. Also, there is a slight bit of pressure on the RCA's of one of the amps so a carpeted 'prop' will solve both of those problems. Right now i've got it temporarily propped so the RCA's are unharmed.

Here are a few random pictures that I took during the install. I was going to take more but I started to run short on time and didnt take as many as i'd originally planned. Each pic is captioned:

Fuse location:

Under the wheel well where the fuse is bolted:

Power wire location inside the car that I found easily accessible and passed through the firewall.

Power wire under the hood.

Pulling apart the center console:

Center console pulled apart. Stereo connector on the left, Climate controls on the right.

Stereo plug cut. I twisted the speaker pairs (+ & -) to prevent noise.

New speaker wire connected to output of stereo. These go directly to the cleansweep in the trunk. These are soldered and heat shrunk. I tried to heat shrink in-line but the stuff kept shrinking before I could get the wire soldered. Its on there good though

Removing the rear seat. There are spring loaded tabs that hold the seat in directly under each 'bucket' between the seat and the floor. You just push the seat down, pull the tab and then pull the seat up. Do this to both sides. There is also a bolt that holds the seat in marked in the picture.

Signal and speaker wires run down the passenger side. I ran the power and remote wire down the driver side to avoid noise and interference (not shown)

Driver door pulled apart

The stock speakers that come out of the door. Yes, that IS a "magnet".

Replaced passenger door speaker with dynamat. No spacer needed and easy install.

Box in the trunk ready to be wired

I've replaced the tweeters a few days ago and am just now getting around to writing up the review and getting the pics uploaded. I'll start off by saying that anyone that has decided to only replace the 6.5" mid/woofers in the doors is seriously missing out on a lot of detail and clarity in the higher frequencies. I replaced one tweeter at a time and between each, I turned on the stereo and balanced left and right to hear what kind of difference there was. The stock tweeter/high-pass filter was clearly lacking detail and clarity. The difference was night and day, just as big as the change in the 6.5's if not more. There are two reasons for this and I will explain.

First, here are the pictures of the stock tweeters AND the high-pass filters.

The first problem is that the tweeter is only rated at 15W (printed on the back) and appears to be made of poor materials which partly contributes to the lack of clarity and detail. The second problem lies within the poor high-pass filter for the tweeter. If you look next to the connector in the last picture, to the right is a small capacitor. This is the "in-line" crossover/filter that i've seen asked about in several different posts throughout this forum.

I was curious as to what the cutoff frequency to the tweeter was... so I made a few measurements and calculations. I first measured the Impedance of the tweeter at 3.8Ω. I then measured the capacitance of the capacitor that is being used as the high-pass filter at 3.48µF (Used Fluke 87 Multimeter). The cutoff frequency of a RC High-Pass filter is: 1/(2π*R*C) so for the filter that comes attached to the stock tweeter:

1/(2*π*3.8*3.48*10^-6)= ~12kHz. The Cuttoff frequency is 12kHz.

WHAT?!?!? Your average 6.5" woofer will only have a response that extends to 6-7kHz. This means there is a large notch in the frequency response of a stereo with this tweeter configuration from 7kHz-12kHz. That is a LOT of information that is being completely discarded (or at least highly attenuated). I would also like to note that there is no low-pass filter on the stock woofer that prevents high frequencies from being passed to it.

Here is where I decided to place the JL Cleansweep Master Volume knob (which I keep set and use the factory volume) and also my Attenuator for the subwoofer... basically the volume knob for the sub.

I drilled a small hole in the back of the storage compartment to pass the wires through but I decided to use velcro for holding the knobs in place. I was going to make a nice plate and paint it black to match and just have the knobs poke through, but I decided to go with the velcro so I wouldn't have to drill more and when I sell the car, I can just pull them off with no evidence. They are perfectly within arms reach and are concealable with the compartment door.

Subwoofer response with no subwoofer EQ or dynamat/treatments:
post #5 of 9
Very nice install, very clean! Excellent work
post #6 of 9
Great job & walk through photos!
post #7 of 9
Thread Starter 
Originally Posted by memphis87 View Post

Very nice install, very clean! Excellent work

Originally Posted by tdogroeder View Post

Great job & walk through photos!

Thanks for the compliments guys!
post #8 of 9
I just had the exact same Alpine component speakers installed in my 2006 Accord and the installer cut my door and put the tweeters in the panels (right by the door hanle). I was pretty surprised, because we had not discussed this before hand. I had assumed the tweeters would just replace the stock ones. He said the Alpine tweeters "might" not fit or sound is good in the stock locations. So, my question for you is,

1. Did the Alpine tweeters fit in the stock (front dashboard) location without any modification/cutting?

2. How is the imaging? Do you get good clarity/sound in the stock location (say, vs having the tweeters in the door?)

I am thinking about having the installer move the tweeters from the door to the stock location and having them buy me new stock (OEM) Honda door panels.
post #9 of 9
Thread Starter 
Hey sorry about the late response, I havnt been on in a while.

1. Yes the tweeters fit in the stock locations. There wasnt any modification really needed, but it wasn't a direct replacement. If you look at this pic:

I basically pressed the new tweeter into the plastic cylinder thing that surrounds the old tweeter. It stretched just barely... and is held in place pretty securely without any adhesive.

2. I get pretty good frontal imaging. Because the tweeters fire against the windshield, the sound from them seem to disperse more evenly across the front. My previous car (Solara) had tweeters mounted in the door as you describe, and you could kindof tell that the sound was coming from the side a bit unless you used the balance control on the headunit to level out the sound.
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