Would it be possible to turn this into a 6th order

[Bass so loud it HZ]

I had a guy build me a wall and it's similar to a 6th just doesn't have a front port so right now its pretty much just a ported wall. I believe it can be done no problem. what do you guys think ?

Click to read more...

 

[hispls 5,000+ posts]

"Possible", I guess, but I don't see where you're going to get an adequate sized port in there or modify volume of front and rear chambers if needed.

What do you hope to gain by doing that?

 

[SlugButter]

6th orders usually have to be designed and constructed extremely accurately to get good results. You could get lucky, but that would be like catching lightning in a bottle. Youll likely need to rebuild as a 6th order from scratch.

 

[Buck 5,000+ posts]

You can. Idk what your goal is but adding any loading wall is going to lower the rear chamber frequency and create a higher frequency resonance in that front chamber. That’s what it’ll technically do.

That clamshell design is actually really good, because the coupling between the rear port and the cabin is very efficient, where the port airspeed doesn’t rapidly slow down after being ejected from the port, air particles are forced to more smoothly around the port opening at back of clam, instead of just being sprayed everywhere violently like it would a flat wall. It’s like putting a choke in your shotgun so the pellets don’t spread too far, roughly. It’s more consistent momentum changes of the air particles.

It also helps shape the waveform front, where the waveform is actually structured while flowing along the clam walls like a horn, and the wavefront stays together better by the time it hits the front of the vehicle and doesn’t break apart and start reflecting into a broken up wavefront like it would if you had a loading wall in front of the clam opening. That helps with efficiency and more like equal Spl radiating from the front opening radiating surface. I think people underestimate clams, honestly; they’re so smooth.

Clamshells and your cabin airspace make the best couple

 

[Buck 5,000+ posts]

Some random data for you relating to accoustic coupling:

You can see how the wavefront stays coherent as it matches or more closely matches the surface area of the cabin (height and width), like waves and air flowing through your clam slowly expanding and contracting as one, instead of abruptly expanding and breaking apart more, like if your port just immediately opened to full cabin area. It’s really air impedance, but haha I’ll leave it there.

 

[Bass so loud it HZ]

Some random data for you relating to accoustic coupling:

View attachment 52875

View attachment 52876View attachment 52877View attachment 52878

You can see how the wavefront stays coherent as it matches or more closely matches the surface area of the cabin (height and width), like waves and air flowing through your clam slowly expanding and contracting as one, instead of abruptly expanding and breaking apart more, like if your port just immediately opened to full cabin area. It’s really air impedance, but haha I’ll leave it there.

View attachment 52884

 

[Bass so loud it HZ]

I've never really seen to many ppl running a clamshell. But I will say for just being a ported box and not having a loading wall it plays a pretty wide bandwidth .it's supposed to be tuned at 27hz but will play under 20 up to 40 with it peaking in the high 30s. It also moves air pretty good which is what I was going for. I got a 158.9 out of it so far but would like to get a little more out of it. I really havent tuned my amps very well or deadend my doors yet so i think it has more. But thats what i was wanting to lower the back port and raise the front port . I figured with a loading wall it would help me to get the wind I'm wanting and also help me peak a little higher so I can also get a higher spl score. But I'm not real knowledgeable when it comes to bandpass enclosures.

 

[Buck 5,000+ posts]

I've never really seen to many ppl running a clamshell. But I will say for just being a ported box and not having a loading wall it plays a pretty wide bandwidth .it's supposed to be tuned at 27hz but will play under 20 up to 40 with it peaking in the high 30s. It also moves air pretty good which is what I was going for. I got a 158.9 out of it so far but would like to get a little more out of it. I really havent tuned my amps very well or deadend my doors yet so i think it has more. But thats what i was wanting to lower the back port and raise the front port . I figured with a loading wall it would help me to get the wind I'm wanting and also help me peak a little higher so I can also get a higher spl score. But I'm not real knowledgeable when it comes to bandpass enclosures.

You should be able to play way above 40 if tuned to 27 hz. The tuning may be wrong or you could have a loading issue; I’m not sure.

 

[Bass so loud it HZ]

You should be able to play way above 40 if tuned to 27 hz. The tuning may be wrong or you could have a loading issue; I’m not sure.

I just went out and tested my bandwidth and it plays down to about 15 can't hear it tho of course and about 40 it starts to fall off after 45 it really falls off . I thought with a ported box you wouldn't have very much bandwidth ?

 

[Buck 5,000+ posts]

I just went out and tested my bandwidth and it plays down to about 15 can't hear it tho of course and about 40 it starts to fall off after 45 it really falls off . I thought with a ported box you wouldn't have very much bandwidth ?

What’s the vehicle, is it a b or c pillar wall, how much wattage are you running, and what’s the ohm load on the amp from the subs? And that’s 4 18’s?

 

[Bass so loud it HZ]

What’s the vehicle, is it a b or c pillar wall, how much wattage are you running, and what’s the ohm load on the amp from the subs? And that’s 4 18’s?

04 jeep grand cherokee b pillar . Two surge 10ks at .5 per pair of subs l. Yes 4 18 inch rs plats.

 

[Buck 5,000+ posts]

04 jeep grand cherokee b pillar . Two surge 10ks at .5 per pair of subs l. Yes 4 18 inch rs plats.

Ok. You have 4 18’s on let’s say 20k to make it easy. Your cabin is relatively tiny. That box being in your cabin is like 4 18’s playing inside of a large sealed box or look at your box in reverse like your cabin is your sub chambers. My point is that your cabin isn’t that big and should be well pressurized by the absolute monstrosity of a system you have; that’s a ton of wave energy density per volume of air. You are losing pressure in the cabin fairly early for being tuned at 27 hz, which you really should check to make sure the tuning is that from the structure of the box. For it to fall off that quickly and not be tuning, you’ve got too big of a box, port issues, 1/4 wave cancellation issues (or some other phasing issue), something of that nature, if I’m understanding you correctly. There’s a mathematical reason why it would fall off that hard, so I would figure the why before you figure the solution.

 

[Buck 5,000+ posts]

If you could wire to 2 ohms, you could see if sub movement is stressing the amps too much at .5. You’d see how it plays wired higher, especially comparing db changes over a range, because playing away from tuning can cause way more stress on the amp, which causes the amp to electrically not be able to handle energy from the coil moving more from the woofer unloading, basically. You could try some things like that too. I don’t think any of this is going to be particularly simple or easy to figure out with all of the factors.

 

[Jimi77 5,000+ posts]

How do the subs respond at say 60-80hz?

 

[Bass so loud it HZ]

If you could wire to 2 ohms, you could see if sub movement is stressing the amps too much at .5. You’d see how it plays wired higher, especially comparing db changes over a range, because playing away from tuning can cause way more stress on the amp, which causes the amp to electrically not be able to handle energy from the coil moving more from the woofer unloading, basically. You could try some things like that too. I don’t think any of this is going to be particularly simple or easy to figure out with all of the factors.

Yeah I'm not that knowledgeable on all this stuff man . And I play it with one window down if not it's not as loud but it is louder at higher freq sealed .I paid alot of money to have this built . It was supposed to be a 6th order but dude messed up and built it for 2 18s . Then had to tear the baffle and all that out and this is what he came up with .

How do the subs respond at say 60-80hz?

I haven't even attempted to play that high I've went up to 55s and I mean it plays but it's not loud