Cabin Loading With Ported Clamshell

[Neo_frog]

I'm sure some of you have seen the new idea for my next build, but I'm still wondering how cabin loading will be as far as opening the windows and doors while playing music.

I've been getting good info from Charger so far, but instead of just bugging him the whole time, I'd like to hear everybody else's advice on it. The goal is obviously 159.9 and we'll see how that goes, but I also want a good bass boxer. If I can't open the doors, then what's the point right?

The plan is 6 15s on 24kw in a ported clamshell similar to Charger's and 2000lade's in the Cruiser. Let me know if anyone has some tips on finding the appropriate port area. It should be able to play everything sealed and open without unloading.

Thanks in advance

[Neo_frog]

Basically in order to build the baffle properly, I'll have to weld a steel frame. I don't want to go through ten baffles to find out what works best... Maybe it's the best thing to do, but I'm looking for a head start. Should I just go big or small?

[Boon]

It's easier to choke down a big port than to make a small port bigger

You want to build it so that it's not relying on cabin air to load otherwise it'll suck for demos.

This means you have to be careful with your airspace (probably not an issue with a cruiser) and the port will probably end up on the smaller side...

[Colin - STAPUFT]

Bump for this. I am about to be shooting in the dark with a clamshell too.

I have wondered about the loading as well. If you use the sealed vehicle to do most or all of the loading- then it will play like crap whenever the doors are open or the windows are down! I drive my vehicle, so that defeats the purpose. I was leaning towards your way of thinking Boon- build the back of the port way on the small side and go from there. Seems that is the definition of a horn anyway. Use the small part of the port to help load the subs and the horn to amplify it. If it sounded like butt, just get in there and cut out the port 1/2 inch at a time.

[Noobtastic14]

i'm interested in where this thread is going

Colin wheres the build log?

-Drew

[Colin - STAPUFT]

i'm interested in where this thread is going

Colin wheres the build log?

-Drew

Not trying to thread jack at all Neo frog (you, boon, ptcary, charger and the hoopty got me inspired for this design)

I am doing everything I can think of on the van to get it 100% before I do the wall. Once I start on the wall, everything else is off. I mean, it could be sitting on 4 flat tires and I wouldn't care as long as I was doing the wall. I work slow anyway so I won't post pics until I am almost done.

I see very painful things in store for your PT Neo frog.

Another question I have- what about distance from front of baffle/inside front baffle to wall/wall to horn terminus/terminus to window? Like so:

I know this is for peak spl numbers, but couldn't you use this same thing for a clamshell? My wall will be too far back for the windshield, but your pt.... that is a different story.

[Neo_frog]

See I know it's easier to make a big port smaller, but that doesn't account for the angle of the baffles (assuming the port pieces are angled as well creating the 'horn effect'). I guess if I started with an independent piece that determined the cross sectional area, I could always adjust the angle to increase or dampen it, but it would be hard to maintain it's integrity during a full blown attack... So maybe just a little stronger angle 'closing' the port, then cut pieces away to increase the port area?

As of right now, the plan is about a 45 degree angle for the actual baffle, then a second stage that will supplement the angle even more to either a > or a =

I thought that the 'port' pieces had to be parallel! Am I wrong there?

Edited March 26, 2009 by Neo_frog

[Neo_frog]

Colin, I would give you an opinion, but I can't see pics at work.

If you wanted to e-mail it to me, that would be cool. I'm always up for looking at new ideas. If something comes up, I might not do a clamshell, but it has to hold 6 15s. pm me if you're interested.

[Neo_frog]

Oh yeah, Ive seen that before on caraudiomag.com. I think I mentioned that setup in my first build on this site.

So far as I've calculated, 51.5hZ is the lowest frequency I can build a 1/4 wave design for since my car is so short (while maintaining a cubic enclosure)

Gotta play mooozik on this next one.

[Neo_frog]

So does anybody have an answer to whether the port walls should be parallel or not? Because that will really determine how difficult it's going to be for trials...