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Discussion Starter #1 (Edited)
Welcome to Kraut's lightweight, budget SQ build.
The goal of this stereo build is to have a great sounding system that is completely stock appearing and hardly adds any weight to the car.
Guidelines:
Maintain stock appearance
Front stage only (eventually active), no rear fill
Single subwoofer running infinite baffle to save weight
Only one amp for the entire system
Added weight must be:
1) kept to an absolute minimum
2) distributed towards the rear axle as much as possible
Sound deadener will be used sparsely
Don't break the bank *gosh*

I've been lurking here for a while and just recently signed up. In the last few months I've learned a ton from this forum alone, read countless inspiring build threads, reviews, how-tos and have been hunting for deals on equipment.
A year ago I had no idea what infinite baffle is, what it means to run active and I thought JL Audio were the greatest subwoofers...
My install experience from previous rides is limited to swapping head units, speakers and adding sub boxes in the trunk. Pretty basic stuff. I thought it was great at the time.

For this car I'm doing things a little different.
The reason for the stock appearance is not because I'm some kind of purist, I just don't want to attract thieves and I've always preferred the look of 'most' stock radios over the shiny, colorful aftermarket kind.
Luckily I stumbled across some OEM looking aftermarket decks:
VDO & Continental / Kienzle. The face plates are matte black not shiny, illumination is orange. The look is very similar to 80's & 90's OEM BMW & Audi. I love it.
I haven't bought the head unit yet, for now I'm running with the basic Kenwood deck that came in the car. Once all the other equipment I received so far is installed I'll probably order the Continental deck.
Eventually I also want to get a MiniDSP and go active.



The car is a '84 BMW 528: 6 cylinders, 5 speed, 4 doors & under 3000 lbs (and I intend to keep it that way). This is right after I washed it the weekend I bought it:



Part of this install is also relocating the starting battery from behind the headlight to under the rear seat for better weight distribution. The new battery is a Odyssey PC680 MJT (16 lbs). I don't plan on running the system ever with the motor not running. I'm also currently switching the stock rear bench for rear bucket seats from the 80's BMW E24 6 series coupe. The new rear seats don't leave any space for the 5 channel amp to fit below them, so I will most likely install the amp below the rear deck in the trunk. This way the weight of the amp is still between the wheels.

I scored this used amp here in the classifieds for $100 shipped: Next Audio Emotions Q.55 5 channel:







Found this pic online:



I'm hoping it will run the sub at 2 Ohms, even though the manual doesn't give any numbers for 2 Ohms. It says the stereo channels can run 4/2/1.5 Ohms but doesn't specify anything about the sub channel.

For the front stage I got some JBL P560C 2 way components new on eBay for $68 shipped. 2 Ohms, 75 watts RMS















The new sub arrived today: Image Dynamics ID15 v3 D4















Next to the 5.25" JBL and the 4x6" Polk plate:



Running the sub IB seems like a win win to me at the moment: Saves weight because there's no box and requires less power so I can get away with just a 5 channel amp. I guess I'll see if it's enough bass for me.
The nice man at the FedEx store where I received the sub let me weigh the raw driver on his precise scale:
20.4 lbs for that 15" sub! Not bad, pretty light.
I was originally gonna go with a single 12" Infinity 120.9w that only weighs 15 lbs, but errbody seems to prefer more cone area when going IB. Since it's my first go at IB I want to give it the best shot and trust the experts. See how easy I up sold myself on a larger sub? :)

I've torn into the car a little so far. Just removed the front & rear speakers, both 4x6". Since I'm not running rear speakers I'll close off the holes and build a new rear deck cover and upholster it. In the front there really isn't much space so I'm building custom baffles to space the 5.25" mids out a little. The cavity in the A pillar is too narrow for the JBLs to recess into:



These were installed by the previous owner in typical previous owner fashion: 3 out of 4 screws used, all 3 lose, grille rattling like crazy, speaker wire ran loosely under dash around other wires without even a single zip tie, bare speaker wire strands wrapped around speaker's terminals then electrical taped. The electrical tape had already fallen off. :) Classic.



The little Polk plates are actually pretty good. I'm gonna use them to build computer desktop speakers out of with a little mini amp from PartsExpress.com More on that later.



Positioning the tweeter: I'm thinking the stealthier the better and I don't like where the factory premium sound option (that my car didn't come with) places the tweeter on the sail panel pointed at the front seats. The mids in the kicks are so much further away from the listener than the tweeters, that's why I'd rather the tweeters not point directly at the listener. The goal is to have it sound as good as possible even before adding the MiniDSP down the road.
I will play with the positioning and decided what sounds best:
A) under the little vent on the actual dash firing up, reflecting off windshield
B) on the A pillar firing across dash
C) on the sail panel



For sound deadening I picked Second Skin Damplifier Pro based on good reviews here. I won an eBay bid from user 'nps' for an open box of 18 sheets (unused of course) for $160.95 shipped. That's around 30 sq.ft. and 18 lbs, didn't want to add any more weight than that for deadening. $160ish is what I was gonna spend on 40 sq.ft. of regular Damplifier new, so essentially I upgraded the quality at the expense of some quantity. I'm happy.



I'll update this thread as I move along. There's a ton of work left to do...
 

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Mmmm some E28 goodness... My first ever encounter with the BMW driving experience, loved every second of it. Looking forward to see how this gets realised!
 

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Love me a clean E28. I have memories of an M5 that belonged to a fellow spectator at Summit Point Raceway that I used to drool over. I was a teenager at the time. :D
 

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Discussion Starter #4
Mmmm some E28 goodness... My first ever encounter with the BMW driving experience, loved every second of it. Looking forward to see how this gets realised!
Awesome, thanks. Hopefully I can get this build off the ground soon.

Love me a clean E28. I have memories of an M5 that belonged to a fellow spectator at Summit Point Raceway that I used to drool over. I was a teenager at the time. :D
I'd like an M5 :) My dad took me to Summit Point to watch amateur motorcycle racing when i was a teenager. Some good memories.
 

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Discussion Starter #5 (Edited)
Oops I did it again...

I'm a terrible person. First I hardly get anything done on my car in the last two weeks, then I buy another sub before ever even installing the first one:
Found this lightly used NVX VCW154 15" monster on eBay for a steal, just over half of the new price shipped and i couldn't resist. It was on my short list of 15" subs to own to try IB in my car.





Next to the brand new ID15







The VCW154 has 20mm xmax, Fs of 26hz. RMS is 850 to 1000 for ported and sealed, respectively.
Vas is 106L, sensitivity is 87db (1w/1m), Qts is .44



I know it's not at all lightweight. It weighs 10 lbs more than the ID15 (30.5 vs 20.4 lbs). I'll probably mostly run the ID and every once in a while switch just for fun. Which ever one is not in the car will be running in my home stereo system.
The modular trunk baffle system I'm building for the car will make it very easy to swap drivers. Each driver will have its own baffle that is attached to the main baffle that always stays in the car.

Some other subs on my list to own and try IB are the Alpine Type S 15", Dayton Ultimax 15", Dayton HF 15" (RSS385-4 HF), JBL W15GTi, ID MAX15, Sundown E-15 v3, RE Sex or Xxx 15" and Infinity 120.9w. The JBL GT5-15 WAS on the list but apparently got discontinued. Same for the JBL GTO 1514D.
On a side note -- I wonder if JBL is about to release a new 15" sub since they don't have a current 15.

Anyway, I'm still gonna try the ID15 first, let it break in and listen to it for a few weeks and then switch to the NVX to compare the two.
Next day off I'm working on relocating the battery so I can hook up the amp so I can hook up the speakers and sub so I can have tunes in my car again... Then there's also plenty of Damplifier Pro still to be installed.
 

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Discussion Starter #6
So I messed around with the sub baffle a little.
Instead of using cardboard to make a template I used some 1/2" insulation foam we had around. It's actually ideal for making templates because it's light, very easy to trim and it holds its shape well unlike cardboard.
I forgot to snap a pic of the final foam baffle template, but it fit neatly to the sheet metal wall separating the cabin and trunk.
A shot of the trunk:



This wall is getting a big hole cut into it and it doesn't even know it yet...
Unfortunately there's a step on the bottom so my baffle has to start above that.
A 15" sub baffle JUST fits there:



Cabin side of ze wall:



There's some factory sound deadening on the trunk floor. Some people have referred to it as tar mat but I have no clue what it is:







It's damn heavy. My plan is to remove it entirely and put down Damplifier Pro not only in its place but everywhere in the trunk. Here's a close up of a chipped piece, it has foam backing. Is that just 80's OEM mlv?



Once I was happy with the shape of the foam baffle I transferred it onto 3/4" birch plywood:





I used a clamped on 2x4 stud as a guide to make the longer cut which worked well. For the shorter cut I just said f*** it and free-handed it. Mistake.

After test fitting the wood baffle in the vehicle I drew on the obligatory Union Jack. Then I used the NVX VCW154's rubber gasket as a guide to draw the cut out circle. I had previously confirmed that the diameter of that gasket was a good fit for both subs to be reverse mounted.





My dad helped me with his router. We made a circle jig out of a metal piece that came with the router and a long screw, using the plunge router base and a trimming bit:





It worked well shy of one little mishap at the end near the 12 o'clock mark. Luckily the woofer's 12 o'clock screw won't be affected.
Tried it on just for size even though this isn't the baffle the woofer gets reverse mounted to:









Fits well.
I then made a second baffle template out of some more 1/2" foam. This oval baffle will be what the woofer gets reverse mounted to. Each sub will have its own unique and custom fit oval baffle. These oval baffles will be easily swapped out to swap woofers. At this point I'm thinking of attaching the oval baffle to the main baffle using T-nuts & bolts, unless someone has a better solution. The reason I don't want to use wood screws is that I don't want the threads to wear out as I'm swapping baffles.

Here's the final oval template. I looked around the house for something large and oval to use for the shape and found a small side table with an oval top. Flipped the table upside down onto the foam and came up with the curve / arc. Turned out way better than anything I could've drawn free-hand:







I then transferred the foam oval onto 3/4" birch plywood twice; one oval for each sub I have so far. As I get more subs down the road I'll build more ovals. The reason why each sub needs its own oval baffle is because each sub has a unique reverse mount cut out (to clear the surround).





Once the first oval was cut out and lined up perfectly onto the main baffle I screwed it down with two screws so I can use the main baffle as a template to route out the cut out. In hindsight I should've used clamps DUH.





And a quick test fit: perfect.



Both baffles' outer edges then got routed with a 1/4" round-over bit to enhance appearance and make it easier to upholster. The camera doesn't really pick up the rounded-over edge well:



The next step will be to attach the main baffle to the car and cut the sheet metal *yikes* You gotta pay to play. I don't plan on ever selling the car again anyway.

That's all for this update. I hope this thread with its step by step pics will be useful to some peeps down the road on the quest to audio nirvana. I certainly have learned a ton from this forum through other peoples' builds.
 

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Discussion Starter #9
Subscribed.
Lookin good. Nice progress.
Thanks guys.
Yesterday I ordered some much needed parts for the battery relocation.

A junction block for the engine bay to run the + battery cable to from under the rear seat:



As well as a 150 amp breaker to protect the + battery cable from setting my car on fire in the case of a collision:



Both should arrive on Saturday so I can go to town this weekend.
The 1/0 gauge battery cable arrived weeks ago, as did the new Oddyssey PC680 MJT battery. I'll use some leftover 1/0 gauge to do the big 3 upgrade as well.
 

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Very nice work! I'm really liking the swapability between subwoofers you have going on there. Great choice of equipment too!
 

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Discussion Starter #12
So I got some more stuff done, progress is slow because I'm doing other work on the car as well. I finalized the battery cable from under the hood to under the rear seat so the car can drive again.



This project is my first time ever making my own cables, using TechFlex, heat shrink and soldering. When I placed my order for the TechFlex and heat shrink at wirecare.com (a while ago) I didn't know that 1/2" heat shrink wouldn't fit over the 1/0 gauge cable, that's why you see electrical tape in the pic. However, just after the above pic my dad gave me some 3/4" heat shrink he had so I actually peeled the electrical tape back off and did it right.

The new junction block under the hood is as far towards the rear of the car as possible, right above the fire wall, to keep the battery cable as short as possible (weight).
There were a few cables attached to the positive terminal under the hood and they needed to be rerouted and hooked up to the new junction block. The starter cable was long enough to be rerouted, just needed to be reterminated. The fuse box cable and one other relay cable, however, were too short so I ran some 4 gauge cable from the junction block to near the fuse box and connected them both. Glad I had ordered extra 4 gauge which will be the amp's power and ground btw.

Fuse box junction before final heat shrink:



Close up of junction: Each cable was terminated with the proper size ring terminal and individually heat shrinked, held together with a M6 bolt and self locking nut...



...then double heat shrinked over the junction to prevent it from shorting out against the inner fender:



How it looks with everything back in place: The junction is below all those relays on the side of the fuse box, the 4 gauge cable running to the junction block is ran along some other factory cables and uses their factory tie down points for a stealth look. The only give away that something is not stock is the shiny, new TechFlex:



On to the trunk.
I temporarily attached the baffles in place so I can pilot drill their mounting holes through the wood and the sheet metal at the same time. The calm before the storm:



Then I removed the wood and enlarged the sheet metal holes with a 1/4" bit because I'm using all M6 hardware:



Installed the threaded inserts into the wood baffles and test fit again:





Used the baffle as a template for cutting the hole. The point of no return:



I used the sawzall for the rough cut, then sheet metal sheers to trim most of the left over material, then a hand file to clean it up. It won't win any beauty contests but it works for now:



When installing the threaded inserts, I used 20 minute epoxy so they stay put:







 

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Discussion Starter #14
Diggin it so far!
Thanks!

I worked on it some more after this morning's update and finished the battery cables. I applied some Ensolite PnS to the floor underneath the battery, the wall it's pressed up against and the inside of the aluminum bracket to decouple the battery. For the ground cable I was able to go to a factory ground nearby (bottom left in the pic).

The brackets that hold the breaker also attach to the same mounting points (aluminum M6 rivnuts) as the battery bracket, the goal was to drill as few holes as possible and to avoid drilling into the floor / outside wall of the car. There's also some Ensolite on the tips of the brackets that rest on the floor.



 

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I had a sub in there in very early stages of my build - small sealed box with eD 6.5" long throw woofer. Upgraded to a 10" IDQ I think after. Rear seat massage option - check :).
 

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Discussion Starter #16
I had a sub in there in very early stages of my build - small sealed box with eD 6.5" long throw woofer. Upgraded to a 10" IDQ I think after. Rear seat massage option - check :).
Yeah that's a popular spot for a sub enclosure and I've considered it as well. However, the E24 rear bucket seats leave no space underneath for it, even to fit the battery I'm hacking into the seat pan a bunch.
I hope a 15" IB on low power hits as hard as any 10" sealed shallow sub I could've squeezed under the stock rear seat... We'll see.
I'm working on the trunk today, removing the factory sound deadening to replace it with Damplifier Pro, hopefully mounting the amp before the end of the day.
I was shocked just how much the factory 'tar mat' weighs while I was removing it one little piece at a time with a scraper. When it was all out I weighed it at 35.8 pounds!!!!! Incredible.
Btw I also weighed the 9'9" long main 1/0 ga battery cable before I installed it and fully dressed with TechFlex, terminals and heat shrink it weighs only 3.9 pounds. Much less than I expected.

Before:



After:

 

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Discussion Starter #17
Does anybody have a / know of a Pioneer Deh-80prs for sale?
I'm looking to pick one up used in good shape, but I can't post in the Classifieds here yet.
If I don't find one used within a few weeks I will probably pick up a new one, they're $211 at jet.com.
Thanks for any head's up!
 

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Discussion Starter #18
So I read in the MiniDSP thread that the MiniDSP doesn't take speaker level inputs. The head unit I was planning to use for OEM looks doesn't have any pre-outs:



...so I guess I'll "settle" for the Pioneer Deh-80prs.
I installed that unit in my brother's 4runner, played with it a bunch and really fell in love with it. My only gripe is its 'aftermarket' looks. Maybe I can spray the faceplate with a matte clear to get rid of its gloss and also black out the chrome trim on the dial.

 

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Discussion Starter #20
How about this deck? The old school looks would be fantastic and it has analog in, digital in, three pre-outs etc. I have always loved the way Naks sound and this one is a rare gem.

RARE Nakamichi MD45Z Car Radio MD Player Aux Autoradio Top Digital In | eBay



Wow MiniDisc takes me back like Mountain Dew Throwback!! I actually love MiniDisc, used to have all kinds of Sony portables in the 90's. While that is a sweet headunit, no doubt, it's expensive and I would still need a miniDSP with it to run active.
My choice of decks is between:
A)something cheap for OEM looks + miniDSP
B)something expensive that does it all (deh-80prs)
 
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