Bandpass box for (2) SA-10's

[lataste 0]

Hello all, I have been a traditional sealed box kind of guy, but I want to try something different. I am going to build a bandpass box for some SA-10's that will be pushed by a SAZ-1500Dv2. The port will be pushing through a ski hole in the back seat. The sub that I have now fires through the port, but I am hoping to eliminate some of the trunk rattles by creating a port that extends through the ski pass. I have taken a few pics to give you guys an idea of what I am trying to do.

I want to fire through a port where the homemade ski pass, the trunk is sealed very well, so I opted to cut a hole.

I have come up with some figures for the SA-10s by using an online calculator, but I'm not sure if they turned out right. Here are some snapshots of what the calculator is saying:

This is telling me that the sealed side of each sub should be .468 ft cubed and the ported area should be .614 ft cubed.

I have no idea what the port should look like, but I tried. I know I'm doing something wrong here, but I'm not sure what.

After taking the calculations from the calculator saying that the outsides should be .468 and the ported should be .614, I came up with the following dimensions. Keep in mind that this picture doesn't show a bandpass box, but it simply assisted me in determining what the outside dimensions should be.

I am looking for any guidance on how to port the box and to confirm that I am at least heading in the right direction. I'm sure that someone has attempted this, but I can't find any info.... Thanks for the help everyone...

[95Honda 486]

I would try and choose a lower bottom end cutoff. Try this and look for a drop in efficiency, that box is super peaky.

I have some good software, I'll see if I model you something good tonight...

[95Honda 486]

Sorry I didn't get a chance to do it last night, I'll see if I can model tonight...

[lataste 0]

No problem, I look forward to the design. Without trying to deviate the post from the original request, which subwoofer would be better for what I am trying to accomplish?

SA-10

FS : 31.6 Hz

Qts : 0.45

VAS : 21.9 L

RE SXX 10"

Fs: 30.7 Hz

Qts: 0.27

Vas: 21.8 liters

FI SSD 10" stock

Fs: 31.0 Hz

Qts: .33

Vas: 15.9

Please base a recommendation on facts instead of subjective remarks like "yo, the sxx bumps the most".

Thanks

[Duran 387]

Xmax needs to be adjusted, it will change minimum port area

[lataste 0]

For a better visual picture, this is what I am trying to accomplish.... minus all of the plexi glass.

Edited December 22, 2010 by lataste

[95Honda 486]

That's pretty much what I pictured. I didn't forget about your design, I will get to it.

Nice thing is, a little of the vent can be out of the box, this will make it nice if the vent ends up being 2 feet long....

[lataste 0]

That's pretty much what I pictured. I didn't forget about your design, I will get to it.

Nice thing is, a little of the vent can be out of the box, this will make it nice if the vent ends up being 2 feet long....

Great...

I have been messing with the numbers for all of the speakers that I mentioned above and am having problems with the Vr and Vf. For some reason they keep coming up between .4 and .1 for either one depending on the configuration. I am guessing that the calculator is off since there is no way I can fit a 10" speaker in a .1f cubed box. This is the calculator that I have been using:

http://www.carstereo.com/help/Articles.cfm?id=27

For example, I tried the FI SSD sub and these are the figures that it came up with:

VF .088?

VR .106?

I'm doing something wrong, but I can't figure it out...

[95Honda 486]

Ok, here is the deal. Those drivers (SA10) aren't easy to model in a usable size box when you factor in a decent sized vent. So, I have 2 possible alignments.

#1 Peaky, but efficient with a decent vent size. Good response from 30-60Hz. I would use this for Rap music/showing off.

2ft3 sealed, lightly stuffed with polyfill. 1.25ft3 Vented, 6" I.D. round vent 31" long (obviously not all in the box) and a 1" layer of fiberglass lining the interior walls.

#2 Less Peaky, less efficient with a long-ass vent. Good response from 30-75Hz. I would use this for normal music.

1.4ft3 sealed, medium stuffing with polyfill. .75ft3 Vented, 6" I.D. 42" Long (your gonna have to figure this one out) and a 1" layer of fiberglass lining the interior.

None of these calculations take into consider vent, driver or bracing displacement, you'll have to figure that out. I wouldn't use les than a 6" I.D. vent for a pair of those drivers with any amount of signifigant power.

Rememebr, the vent doesn't have to be straight and be in the box, let you imagination go here. If these won't work, you may have to look at different drivers.

-Mike

[lataste 0]

Ok, here is the deal. Those drivers (SA10) aren't easy to model in a usable size box when you factor in a decent sized vent. So, I have 2 possible alignments.

#1 Peaky, but efficient with a decent vent size. Good response from 30-60Hz. I would use this for Rap music/showing off.

2ft3 sealed, lightly stuffed with polyfill. 1.25ft3 Vented, 6" I.D. round vent 31" long (obviously not all in the box) and a 1" layer of fiberglass lining the interior walls.

#2 Less Peaky, less efficient with a long-ass vent. Good response from 30-75Hz. I would use this for normal music.

1.4ft3 sealed, medium stuffing with polyfill. .75ft3 Vented, 6" I.D. 42" Long (your gonna have to figure this one out) and a 1" layer of fiberglass lining the interior.

None of these calculations take into consider vent, driver or bracing displacement, you'll have to figure that out. I wouldn't use les than a 6" I.D. vent for a pair of those drivers with any amount of signifigant power.

Rememebr, the vent doesn't have to be straight and be in the box, let you imagination go here. If these won't work, you may have to look at different drivers.

-Mike

Great feedback, would either of these drivers be a better solution? I mainly listen to electronica and alternative, but mostly deep/progressive house music as I used to be a producer/DJ. So expect a lot of 909 kicks and baselines around 120hz. I will have (2) 8" mid bass woofers in the front soundstage with an MS-8 for equalization. The subs will mainly be used for deeper notes, but not full SPL.

RE SXX 10"

Fs: 30.7 Hz

Qts: 0.27

Vas: 21.8 liters

FI SSD 10" stock

Fs: 31.0 Hz

Qts: .33

Vas: 15.9

I am trying to fit it into the space of the trunk so it doesn't interfere with the opening as I store my cleaning supplies inside. I'll post pictures later...

Edited December 22, 2010 by lataste

[lataste 0]

I should have also asked how I can tell that a subwoofer would be good for a bandpass enclosure, maybe that would limit my selection criteria a bit more.

[95Honda 486]

For bandpass, you really need a woofer that is more suited for a medium to larger box and a have a decently low Fs. Something with a usable Qts also, like .4ish range...

The problem with a the woofers you have been looking at is they are designed to work well in smaller enlosures (look at thier Vas). And this becomes a problem when you are trying to build a bandpass due to so much vent area needed. Unlike a normal vented 4th order box, bandpasses have all the output coming through that port. This is also why I would only use a 6" I.D. pipes as a minimum with the designs I mentioned.

Do you already have the drivers?

If not, and you want to do a bandpass these would be my choices:

My link Good balance price/perfromance... Use single, or a pair in about 4-5ft3 total.. A pair in a bandpass would be very loud.

My link Again, good balance price/performance. Use a pair.

My link Very high performance, great SQ and parameters would lend to a great, flat response bandpass. Only need one of these and still have the right box size.

My link Either of the FI X drivers would be suitable, if you use the 10s, you would want to make it a pair.

[lataste 0]

For bandpass, you really need a woofer that is more suited for a medium to larger box and a have a decently low Fs. Something with a usable Qts also, like .4ish range...

The problem with a the woofers you have been looking at is they are designed to work well in smaller enlosures (look at thier Vas). And this becomes a problem when you are trying to build a bandpass due to so much vent area needed. Unlike a normal vented 4th order box, bandpasses have all the output coming through that port. This is also why I would only use a 6" I.D. pipes as a minimum with the designs I mentioned.

Do you already have the drivers?

If not, and you want to do a bandpass these would be my choices:

My link Good balance price/perfromance... Use single, or a pair in about 4-5ft3 total.. A pair in a bandpass would be very loud.

My link Again, good balance price/performance. Use a pair.

My link Very high performance, great SQ and parameters would lend to a great, flat response bandpass. Only need one of these and still have the right box size.

My link Either of the FI X drivers would be suitable, if you use the 10s, you would want to make it a pair.

I have not purchased the subs yet, but this may be too complicated for me. I am about to give up and just go with the usual sealed.

[CrazyKenKid 64]

hey have you picked a sub yet? also as for your box design I would like to recommend a good friend who designs boxes on the site! here are the two he got to me! the first one is my box and the second one is for my girlfriends car which the build hasn't started yet!

this is his site here

http://nightmareaudio.com/

also checkout the glossary section! it is pretty good read!

he can work with ANY sub and with any car! if you like I can give you his e-mail so you can get in-contact with him! he likes to specialize in the crazy style boxes lol hell if you give him good numbers he will design a box to port right into your car through that hole in the rear seat lol

[95Honda 486]

Ahhh, it not complicated. Pick a driver(s) that fit the criteria and someone will help you with the design. Then build the box....

[lataste 0]

Well, I went to my local high end audio shop to look for assistance and they talked me into a 12" Sxx. After coming home, I continued my research and downloaded Bass box pro 6 and started messing with different speakers and I am convinced that I can get (2) SA-8's to work. In order to still be able to use my trunk, i would like to stick to no more than 2' cubed. I am going to keep messing with the dimensions, but I think it might work, what do you guys think?