Quote:
Originally Posted by GSMITH
After rereading your original post your real question is about the box shape. What you will have is a bandpass box. See http://mobile.jlaudio.com/support_pages.php?page_id=151 for some basic information. I like your idea but there is no way of knowing how it will sound until after you make it. There are some sites I have seen that try to calculate different box designs response but your final results may not be what you simulated.....I think if you do not add the second layer so you end up with a bandpass and instead have a sealed box it would sound good. If I wanted to use the space behind the seats I would build a sealed box and just cover the speaker with a flat grill painted to match the interior to protect it. . |
Interesting read, but I wonder if what I'm contemplating will really be a true 'bandpass' design? If the speaker is sitting in a sealed 'box', facing up, it would then require another enclosed box with a port to be a bandpass, right?
All I was thinking of doing was making a sealed enclosure of the required volume, with all sides except the front baffle for the speaker done in fibreglass, contoured to the floor and sides of the rear compartment. The carpeted panel sitting above the baffle/speaker of this enclosure would only act as solid place to put luggage or whatever, and the opening across the width (facing front) would not be a port, just, well, a 'vent' to allow the sound out. I did up a crude drawing to illustrate. In reality, the enclosure would probably be deeper to achieve a minimum of 1/2 - 3/4 cu. ft.
I was thinking that the set-up would work even better if the majority of the surface of this panel were made of some stiff mesh, or plywood with lots of holes drilled into it, with carpet over it. On my 380SE, I find that the thin masonite hatch-covers over the first-aid kit and storage compartment (thin plastic themselves) as well as the sheet metal package tray are what I'd call 'acoustically transparent' for bass. In other words, unless there is a steel tank full of gasoline and a heavy steel 'wall' between the bass source and the listener (as is the case with the SL), sheetmetal and masonite don't interfere with good bass transfer. I'd think carpet would act very much the same.
Of course, having the trunk space to let the sound waves bounce around in would help too....lots of theory here, I guess, but I'm basing my guesstimate of how this setup will perform more on what I've experienced with the few I've built myself. I'm no expert either, just a DIY'er and I love to try different stuff, and I know you know what I'm talking about!
Quote:
Originally Posted by GSMITH
I would be interested how you ported your street rod. Got some pictures?
|
I documented the 2 systems I built and rebuilt in my rod on my website. Grab a coffee while it loads, it will finish, believe me...
http://bryceandbernie.homestead.com/SoundSystem.html
The 'ports' are really just a couple of holes in the steel wall separating the trunk from the cabin, covered on the inside with grilles and carpeting in the trunk. This, plus the 380SE experience, convinced me that it doesn't take much to let the bass 'out' from the trunk to your ears.
Joe (jfilipcic), that's a really inventive design. Very little volume though, what does it sound like, and how do you keep passenger's feet from accidently punching out the speaker???