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Discussion Starter #141
I fired up TDA to set the delays. Thing went super well with the right side:



I need to figure out what that hump from 90 to 150 is about.

I'm fairly sure the two strong lines above 3k are due to reflections.

The left side is wonky:



That HUGE deviation at 400 is weird, and I'm not sure what to think of it. It's nowhere near a crossover point.

The combined left and right isn't terrible though:



I couldn't get a real listen to on the way home because I had a huge Pelican case in the passenger seat.

The only EQ I've done so far is a cut on both sides at 3k. I haven't messed with the allpass filters yet either. Crossovers are:

Subs 70Hz LR24
Mids 70Hz LR24 - 1600Hz LR24
Tweeters 1600Hz LR24
 

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Really cool that you could fit them here, what was there originally, some storage?
And does the box act a bit like a bandpass with this somewhat “restricted” opening?
 

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Are you using the APL1012 now or still the APL1?


Nice job on the enclosure. :)
 

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Discussion Starter #144
Really cool that you could fit them here, what was there originally, some storage?
And does the box act a bit like a bandpass with this somewhat “restricted” opening?
There was a plastic shelf for the top to sit in when folded down, LOTS of wasted space under it. There were also three storage bins. two behind the seats, and one above the center console, that went below the rollbar. I didn’t use the bins, so i eliminated them.

I haven’t done any measuring outside of TDA yet. This is the AFR chart from TDA:

Right Side:


Left Side:


Both Sides:


Keep in mind this is a from a single point in space, and the only EQ right now is a cut at 3k.

Are you using the APL1012 now or still the APL1?


Nice job on the enclosure. :)
Thanks!

I'm using the APL1, and letting the JL VXi amp handle the crossovers and delay.

I plan to purchase an APL1012 for the Bronco, and a few for my fully active home theater setup :)
 

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I like the downfiring setup, lots of sub in a small place!

In terms of vibration - do you notice the box vibrates sitting on those "feet/legs" directly on the metal body of the car - or have you used something to cushion where the box hits the car underneath?
 

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Discussion Starter #146
The box is clamped into place by the roll bar, so I’m not too concerned about it rattling. I did find a rattle yesterday afternoon, but I think it’s a trim panel. I still have a lot of work to do back there. The box legs let sound come out from the front and back, I need to adjust it so sound only comes out the front. This should help with rattles, as well as a weird delay issue I have.

A bigger problem I have it the top, it causes all sorts of fun issues in the bass/midbass area. If I use my arms to brace the top, the problems aren’t as severe and effect a smaller range of frequencies. I exported text files from TDA and imported them into REW so I could compare them, here is the left side:


(The Y-axis is ms, not DB)

The “Stabil” measurements are when I braced the top with my arms. The back window(glass) moves a LOT when running a sweep, and I’m not sure how to brace it. However, right now sound from the subs can get out from under the box in the front and the back of the car. I think I’ll notice a difference by blocking the back, so sound ONLY comes out the front. This should help the back glass some. I have a couple ideas on how to help the top section of the top as well, but it won’t be easy.

All that said, with only one EQ adjustment, gains set very crudely by ear, and delays set the best I could get them so far, it sounds pretty good. The stage is as wide as the car, there is a hint of depth, there is a mediocre center, the bass is upfront, and there is good impact. It’ll only get better with more instal fixes and tuning!
 

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What a fantastic install :D And I'm really envious of your sub box as I have a PRHT so no room back there as it's all used when the top is down :(


Josh
 

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Discussion Starter #148
What a fantastic install :D And I'm really envious of your sub box as I have a PRHT so no room back there as it's all used when the top is down :(


Josh
Thanks!

You may have to go with a shallow passenger footwell sub if you want something more than the doors can handle.
 

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Discussion Starter #149
I did some tuning today:



These are APL measurement files imported directly into REW, it makes it easy to show measurements in a format everyone here is familiar with. Also, I discovered today that you can import the DAT files APL Workshop generates directly into REW, super handy for setting the PEQ's in the amp!

So I did that and used REW to help guide me on setting the PEQ's in the amp.

There is still a problem on the left side that peaks around 150Hz, but the rest looks great. After a short listen, it sounds great too!

I still have stuff to fix, and I'll tune from scratch when I do. In the meantime, this is a VERY enjoyable setup!

Alos, I made a mistake early on when tuning, can you spot the mistake when looking at the REW files? http://lumbermansvo.com/APL/Miata/Miata.mdat
 

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Discussion Starter #150
This hobby is dumb.

If I had taken up knitting as a hobby many years ago I’d have saved a ton of money, and would have endless scarves and sweaters.

I’m on a work/vacation trip in Florida and drove the Miata down from Texas, I spent fours days on two lane roads with the music cranked up just enjoying the drive. Four days is enough to reveal lots of flaws in the setup, and there are two big flaws.

This first is road noise. I didn’t think it was that bad until I drove for three days in the rain. The noise from rain water kicked up by the rear tires just revealed how much work I have to do in the rear of the car. There are definite gains to be had by treating the area where the sub box is.

The other is that 100-250Hz dip on the left side response, even after tuning. I’m fairly certain that it is from the under side of the dash being open on that side of the car. I need to build a panel to fix that.

I also have a plan to add some sound absorbing material to the soft top. This will help stabilize it and improve resonance in a much wider frequency range than you might expect.

And last, I want to rebuild the sub box. After seeing how the soft top and the box interact with each other, I can probably gain at least another .5 CuFt of space to help the subs play lower, and get the most use of the little power they have. Also, with e redesign I can keep the sound energy going forward, and keep any energy from going towards the back of the car and into the top storage area. I will definitely keep both drivers on the passenger side of the car though, right now the driver seat doesn’t vibrate at all from the subs. However, the floor does, so I should probably fix that too…
 

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Curious to see your soft top deadening tricks.
I’m not bothered by the rain here in LA and am satisfied with the noise level, but since I’ll have to change it soon that could be useful.

So you plan to seal most of the rear area around the sub?
I know I had drastic difference between my previous coupe and the actual convertible (same car model). It’s almost like if the soft top ate some of the bass, it also smooths it out a bit, well that’s from memory.
But had to go 2x15 or 1x15+PR to get what I wanted.

I wonder if there’s a way to simulate the response, treating the soft as a giant PR in a huge front chamber of a bandpass box (us being in this chamber of course).
 

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Discussion Starter #152
The top deadening will be fairly simple, getting it to look good will be difficult. Unfortunately I can only do one section of it due to the way the top folds up.

Getting all the sub energy to go forward into the cabin *should* be beneficial, but I'm not expecting it to work wonders. However, it should result in less sound going into parts of the top I can't treat, making the overall response better.

Realistically, this stuff is borderline "diminishing returns" territory, and most people would be thrilled what I already have. And that's why this is a stupid and expensive hobby. I really should be working on the Bronco/Home theater.
 

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Discussion Starter #153
This morning I was washing the car and the rear spoiler lifted a little, I gave it a few gentle tubs and it came right off with no damage! There was three broken clips and tape holding it on. Now I get to track down the right clips and tape to reattach it. In the meantime, it looks stupid:



After the car wash I went out to retune it, I made a few mistakes on the initial tune and wanted to fix them. Instead I wound up removing the sub box and built a trunk baffle, stupid hobbies... :p

I had been thinking about doing this for awhile for a few reasons. The biggest is that the top sometimes takes effort to go down because the way the glass sits on the box. over time it developed a bunch of rattles where the rear fo the box sat on the sheet metal and there was no real way to fix it without modding the body itself. There were also rattles from all the plastic bits behind the seats.

I started by removing the rear firewall and drilled out the spot welds that were holding the three pieces together.



Next up, I used the center piece as a template to make the base of the baffle. Most of the mounting points are on the same plane, so this worked quite well.





I bolted up the end pieces of the firewall and the baffle:



Next was to trim the gas filler protector to fit with the baffle. A test fitting:



After some more trimming, with the uncut trunk panel in place:



Next up I made the second baffle piece with the sub cutouts and notches for the fuel filler:



With the subs:



From the front:



I will replace the factory roll bar with a much better looking aftermarket one to really clean up the looks back there. I'm ditching most of the plastic behind the seats to get rid of rattles too. I'll be going with a clean carpeted look back there. the fuel door opener is in the center storage bin, so I moved it. The location is temporary until the new roll bar goes in:



Obviously, I still need to seal it up properly and make it pretty again. The top now goes down effortlessly, I lost zero trunk space too.

I did wire it up and turned it on. I set all the sub EQ's flat and gave it a listen. So far it plays deeper than the box did, and gets a little louder. The few rattles I have are FAR more wicked than before, but they shouldn't be too hard to fix, some butyl rope should take care of it. Well worth the few hours I have into it, and the old box is now by the curb for the trash man to pick up tomorrow. I also have the ABS plastic so I can fab up an under dash panel for the driver side.
 

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Discussion Starter #154
Today I built the underdash panel for the driver side. It wound up being about 16x16", that was a big hole to fill!

Just some simple ABS plastic cut and bent into the right shape:



And I threw some CLD on it for good measure:



A crappy pic of it in place:



It bolts to a couple factory studs in the firewall, and sandwiches between the dash frame and under dash trim panel. If I need to I can screw it to the dash frame later.

I REALLY hope this makes the dip on my left side go away, as seen here on the blue trace:

 

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Discussion Starter #155


Today I worked on the driver seat, it's hard to show in pictures. Fortunately, because the car is so small, tall people are constantly trying to get more headroom, so all the info I needed to do this was already online.

The seat bottom bolts to the top of that L bracket. I unbolted it, trimmed the seat pan some, the bolted up back up to the underside of the L bracket. In total, this lowered the seat by about an inch. The seat tray now almost slides on the floor.

It feels better while sitting in the driveway, I'll see tomorrow on the drive to work how it feels while driving. Of course, the stage should appear to be a little higher. Also, It'll be easier to see traffic lights!
 

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I don't think I've seen IB in a convertible before. Interesting. I have not pulled my CLK apart as far as you've explored, so not sure it can be done with my car.
 

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Discussion Starter #157
I don't think I've seen IB in a convertible before. Interesting. I have not pulled my CLK apart as far as you've explored, so not sure it can be done with my car.
So far it's working pretty well, FAR better than the sealed box was. I'll seal off the trunk and retune it this weekend. Then I'll just have the rear area to carpet.
 

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Discussion Starter #158
I got a bunch done today!

I started by ripping out the trunk baffle, then I chucked half of it in the trash, I kinda wish I had tossed the whole thing, but oh well. The baffle was made up of two pieces of 1/2” birch. Because what I did last week was mostly a proof of concept, the trunk side piece was originally cut very crudely, especially the subwoofer holes. I tossed it and made a new one with much tighter tolerances. I also glued the two pieces together instead of screwing them together.

Speaking of screws, one of the steps was to add mounting studs to secure it instead of the wood screws.



I wrapped the other side, so I needed to countersink the bolt heads. I filled in the area around the bolt heads with silicone so they don’t spin if I have to remove this piece.



I sprayed the interior side with truck bed liner to make it look better until I cover it up.



I forgot to take pictures on the bench, but this is the trunk side after wrapping with black vinyl.



In that picture you can see that I also sprayed the fuel filler cover in bedliner too. Now I just need to figure out the best way to fill in that gap and cover the fuel filler tube.

I did plug that hole there so no air get through. I removed the original fuel tank access cover from the original firewall by drilling out the spot welds. I then added a piece of CLD to it, put some butyl tape under it, and remounted it. here it is with most of the spot welds drilled out.



While bedliner and silicone was drying, I covered the subwoofer wires with split loom and zip tied them to a factory loom.



Next up I needed to seal the sides of the firewall. One goal was to avoid using spray foam if I could, I just don’t like how permanent and ugly it is. I had a few sheets of Kolosus around, so I used those. This is what the area looked like to start with:



After the Kolosus:



The trim panel fit back into place perfectly, this is important because it directs water from any potential leaks from the top into a drain that is built into the chassis so the water drips out under the car. it’s kinda brilliant actually.

I tossed a scrap piece of Ensolite over the rear area to cover up the mess until I do the proper treatment back there.



What it looks like right, with the baffle and subs in place. This is a higher res picture, if you click on it you can see some of what I did to seal it.



When I ordered the soft top for Ol Smokey it came with this cool 1/2 thick foam with a sticky side, it sticks REALLY well. It’s also squishy, kinda like the Ensolite. Every surface with a bigger gap was treated with this foam. I put butyl tape on the surfaces that mate directly to the firewall.

At this point I fired it up and was immediately disappointed that it still rattled! I I got out with it playing and heard the rattle outside too, it was coming from under the trunk. I climbed under and pressed on a heat shield directly under the trunk and the rattle went away. The only way to fix this would requiring dropping the exhaust behind the axle, ugh.

I opened the truck to look at the sub s playing, because we all like to do that on occasion, and then I saw it. I hadn’t reassembled the trunk yet, and the screws that hold the fuel filler tube guard were rattling on the trunk floor. I reassembled everything and gave it another listen, no rattles!

I listened to a few songs and am VERY happy with how it sounds. This was a HUGE improvement over the sealed box. Not only is the bass much louder, but it’s significantly more accurate. You can hear the difference in songs with acoustic instruments.

There are two annoying problems with the doors, so I fixed them while I was going. One was the left tweeter. it rattles in the door in just the right way that it sounds like the tweeter is blown. I nearly had a heart attack the first time I heard it! But if I push on the tweeter area in the door, the rattle goes away. This is how I originally mounted them:



I don’t like to cut things up if I can avoid it, but I suspect the rattle is from the extended tabs, so I cut them off:



I haven’t verified if this solved the problem yet.

The other problem is the passenger door. It’s a VERY tight fit with all the CLD, Ensolite, and MLV in the door. because of the tight fit, the screw mount for the handle keeps popping out. When it pops out, the door card just flops around. While I was modding the tweeter mount, I investigated why this was happening. This this is what kept popping out:



See those tabs on the side? Those were folded over. I gently pried them back up and popped it back into place. Everything went together well, and the door feels tight now.


Next I went to tune it and I couldn’t find the analog input cable in my glovebox, hmmm. I dug a round and bunch and was able to reach my hand far enough into the dash to feel that I had removed the analog cables from the APL1. I don’t remember doing that. So I pulled the center console and radio housing to add the cable. While it was out I went ahead and modded the factory AUX input so it now plugs into the APL1.



After cutting off the pigtail I added RCA connectors to it:



Before taping everything up and grabbed my meter and check for continuity to verify that I got everything correct. I didn’t, so I had to de-solder it and start over. After I fixed it:



I put it back together, but had no sound, hmmm. The APL1 was showing signal for both analog and digital, so I moved on to the amp. I fired up TüN and it showed NO tuned at all, strange. There was also a firmware update available, so I did that, the reloaded the tune. Still no sound, but it was telling me there was no digital signal. I must have accidentally unplugged it when I had the radio housing out. It was getting dark so I just closed up the car, and am now wring this.

Tomorrow I’ll get it working again, and start tuning from scratch.
 

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Discussion Starter #160
Tuning in the stupid Texas summer heat is horrible, so I haven't done much. Today I dipped into my travel tech gear and found my USB extender/hub that can run out to 150 feet. With this I was able to have the amp, APL1, mic, and USB sound card all at once, and work from the comfort of the home. The whole reason behind the retune was that I accidentally borked my TA setting when tuning the subs in their new location.

So after tuning the individual drivers, and setting their levels somewhat close to the target curve, I fired up TDA. After playing with the crossovers, TA, and allpass filters I was able to get this:



That is the whole system, left and right + subs. I clearly need to work on fixing some reflections to clean it up some, but it is also my best TDA graph so far. Oh, and it sounds pretty good too!
 
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