dannichols

Is there a way, using MDF rings or something else, to tilt a woofer in one direction on a swaure box that is already complete? For instance, if the ring was 1/2" on one end and tapered to 1 1/2" on the other, could it be glued to a flat MDF board to give the woofer a slight angle? My 10" sub sits below the floor directly under the strut bar, I want it angled more towards front than straight up at the bar/window.

JimRHIT

iTrader: (6)

yes, it would work fine, but thats gonna be hella hard to make

motown

^ x 2. Can be done, but do you really want to? With a flat ring and some fiberglass skills, you could rip the front off of the box and re-set it to whatever angle you want. That's what I'd do, but that's because I know how to. Not an easy thing to do the way you've proposed. Good luck!

dannichols

I have the skills, but -- the top of the box has to be completely flat or the false floor/trunk mat will not lay down on it correctly , had to cut a hole in both of those pieces for the sub to stick out through. I built the thing with fiberglass bottom/sides and an MDF top. It was a PITA trying to build the box to exactly fit between the false floor and the dynamatted trunk bottom - it is only 6" tall. Anyway, I was thinking the rings might not work if cut at an angle because the inside diameter of the ring would still be straight 90^.

motown

mmm, see your point about the mat. So the ring can't be any wider than the sub already is, right? I would still think that glass is the way to go. Set the sub up in a 1/2 inch ring and just tack the cloth from the top of the ring straight down so that the profile matches the original hole you'd cut out. May look a little funny, but should acomplish the objective. Man, that's tricky! Like I said, good luck!

dannichols

Excellent idea Motown. Yes I wanted the ring to be the same size as the perimeter of the sub, if it stuck upward much more than the one I have (which really can't be seen now, I was going to paint or cover it black on the sides.

For now I think I will scrap the idea and just have the sub shoot straight up with a straight spacer. I notice there are a lot of rattles from the rear hatch area, strut bar, window, etc. I wanted to minimize that a little by aiming the sub forward. Tilting it would also angle the magnet for better clearance from the bottom of the box. If I got enough clearance I was going to replace the 10" Alpine with a 12" sub. I guess there is no "rings are us" store out there ;-)

Zrated

Can you mount the sub in a 1/2 inch ring and put a couple spacers around the side you want angled out. The use fiberglass to seal it up around the edges.?

dannichols

Thanks Zrated. The box looks and fits really clean with all MDF on top (actually you can't see the box at all, just the sub, so I didn't have to sand or paint anything. I do believe I could angle it slightly without too much fiberglass to cover up the gaps, but I was really looking for a more severe angle and I think it would either show and look home-made or affect the way the trunk liner and mat fit.

In all I think using the forward part of the lower trunk for a box was a good idea. I fiberglassed from the front lip area back past the metal pedastal that once held the spare wheel. Now when I put the completed unit in, that same pedestal holds the box in place really tightly.

motown

Damn, I can't find it now. Yes, there actually is a "rings 'r us" store. I just searched for like 30 min's and couldn't find it though. Maybe one of the other forum members can chime in. They're a car audio supplier that also sell prefab rings for fiberglass work. Actually though, if you have a jig saw, it's REALLY easy to make these on your own. The trick's shaping 'em down the way you want them.

dannichols

COOL! Please find that website.

I had one of my typical crazy ideas at lunch while looking around Home Depot just now. Anyway, they have 5 gallon white pails for painting or car washing, and the bottom diameter is a little over 10". I was thinking of propping up one end about 1/2" and pouring resin in there. Put in some fibermat (a ring circle of it) and let it dry. Then follow this up about 3 more times. Do you think gravity would help me create a fiberglass ring that is 1/4" on one side tapered to 3/4" on the other. If it could, I would simply cut out the ring with a jigsaw and glue it on to a 1/2" MDF ring. Then glue the whole thing to the MDF Top of the box and mount the sub on top. Crazy huh?!

motown

Actually, that's genius! Just line the bottom of the bucket with blue painters tape or something and use it as a mold. Build up a layer or two and pull your mold out. Add more glass to the inside and trim the whole thing to sit at the angle you want. When the angle is right, you can just cut out the inside diameter of your sub from the top and glass the whole piece to the top of your box. I really don't understand yet just how much angle you want, but this is a really great way to get prob. 30 degrees of rear tilt to the enclosure. The base will now be ovular, so you may have to trim your carpet just a little bit, but you're absolutely on to something with that idea. Don't think you'll need any mdf at all to make it work. Nice thinking!

dannichols

Thanks Motown, I'll take some pics this weekend. I've let resin dry in quart plastic containers many times and it pops out when I bang on the container upside down. I don't think the Fiberglass will stick to the bottom of a bigger pail but maybe?? Anyway, did you get what I mean about using gravity to make the angle? I want to have the bucket tilted while I am pouring the resin so that the top surface of the resin will be flat-level -- but the bottom will be progressively thick to thin because the bucket isn't sitting flat. Damn, I wish I could post a picture on this forum..but I think I can make the whole thing inside the pail and when I take it out it will be ready to go except for the 9" hole. Thanks again!

motown

Actually, no I didn't. But now I do. That would be mighty thick and take for ever to cure, but I don't see why it wouldn't work. You'd also spend a mint on resin. If you're going to do that, I'd think about throwing some cat hair in there to help solidify the resin mixture. Alternatively, get a smaller bucket with outer diameter equal to the inner diameter of your sub and somehow screw them together, pouring resin in between. Would save you some cash on resin, 'cause that stuff ain't cheap. Great idea for sure!

dannichols

Motown, you know where I'm going with this. I'll try and see how it looks. Anyway, here was some sketches I made of my plan: http://mysite.verizon.net/res7sbn3/

Thanks,
Dano

motown

Heya Dano,

Yep, def. along the same lines. Again, if it were me, I'd ditch the mdf ring and just flip that resin piece around so the tilted portion is down. Looks great tho!

motown

Oh, and I think you're tilting the speaker the wrong direction from that picture. Really, you want to maximize the reflection off of the rear of the vehicle. I'd angle the woofer back towards the hatch.

Mike

dannichols

Really, the other direction? I've heard that before buut don't understand why. I mean there is so much rattle from the rear bumper and the glass back there. Does the extra travel of the bass freq improve its sound or something?

motown

the way it was explained to me is that the more reflection (and therefore distance the wave travels before it gets to you) you get, the more the wave expands thus increasing db. I can tell you also that from ALL of the systems I've designed, this is 100% true. Does it cause more rattles? yes. Do you then need more sound deadening as a result? yes. Is it worth it? Oh boy is it. IMO, difference is night to day. My advice, see if you can't try it both ways. This ring should easily enough turn around from the one direction to the other. Give it a quick test run pointing both ways and see which you like best. That's really the only way to tell.

dannichols

That makes sense, with the sub so close no matter where you put it, having more travel seems important. But pushing 600 watts you would think one could compensate for that decibel loss and minimize rattles, we will have to see.

Do you have a mount under the strut bar? I had one but removed to allow big golf club bags I carry. The one worry I had about mounting under the strut was how it cut the back of the car in half. Yes, the sub was firing to the back of the car like everyone suggests, but how does it then travel to the front of the car? OVER the top of the enclosure right? Well that space is only 2 1/2 inches tall. Seems that mounting the sub there to me would trap too much bass behind the strut tower and cause massive rattle.

motown

By mount, I assume you mean box. no, my box is built into the driver's side rear of the car firing sideways. If you fill in the whole space under the strut tower, yes the only room it has to travel back into the car is via the space above the strut tower. Is that a bad thing? I don't know, you tell me. How did the other enclosure sound? I would imagine it sounded pretty good, but you'd be the ultimate judge. The other thing to remember is that 30 hz is the limit for audible bass. Everything below that's felt by the body. And below 80 hz, bass is non-directional. So you'll never be able to tell where it's coming from anyway. After 100hz, your midbass drivers in the doors should take over. That's how I have my x-over points set. As far as 'trapping' bass, the design you have on your website doesn't cut off that space under the strut tower completely, there's still plenty of space for sound to travel. I think it should be fine. But, without my building the system, I can't guarantee it. Oh, and don't be so sure about the 600 watts thing. Seriously, I'd test it first...