[iH8usrnames]

Subwoofer in crawl space delivering sound to patio

Last year I had an idea of using a single sub for all sorts of purposes and went through loads of gyrations to see if I could make something work. In the end, I did nothing of the sort.
To revisit my old thread and see naivety at work: https://www.avsforum.com/forum/155-diy-speakers-subs/2995528-terrible-idea-i-am-sure.html

The 10" driver I had was used in a single sealed cabinet for several months then retired when I built these for the living room (the dual 12" cabinets attached). I am still applying finish, thus they are a bit of a mess in these photos.

Quite a bit has happened over the past year.
Bought a NAD C658 DAC with Dirac - thus have resolved my desires for DRC.
Built those subs, which are ridiculously powerful for my use.

The big development, started working on outdoor theater on the patio.
We just bought a small projector and a cheap 10' diagonal projection screen to test viability and my wife is hooked. The ability to watch 3d movies while roasting marshmallows is a big hit. She has totally bought into the idea of setting up surround sound back there too.

The plan for next year (thus homework now).
- Install two poles to hold a 15' diagonal screen. The poles will be installed above the retaining wall; the poles and screen will be removable - This is have no problem with, at all.
- Buy five outdoor speakers for basic surround setup. These will have to be under $200 a pair (she bought into it but $1000 on outdoor speakers is a NO GO). I am considering something from OSD Acoustics. Simple sealed boxes.

Why I am posting this?
Under the sliding glass doors (which will go away soon) is a conditioned crawl space (the photo is about some insurance work, ignore the red oval).
I would like to build a cabinet in the crawl space that will feed through the wall to the patio.
Initial thought is a band pass cabinet where the ports are extended out of the cabinet through the wall. I could use plugs to close them off when not in use.

Needs:
I do not need extreme volume - as you can see I have neighbors close by.
I really do not need to hit below 40hz. In fact, 30hz is about as low as I would like to go; I am not trying to create a THX experience, just a nice experience.
Would like to keep the driver cost below $400 total (1, 2, or 4 drivers would need to come in around $400 total).
Amplification will be resolved in the future.

I am open to suggestions and ridicule.

 

[noah katz]

A more descriptive title would likely get you more help.

Anyway, I like the bandpass idea.

Your SPL and freq requirements should make this a straightforward project.

Sounds like the much-discussed and affordable 12" JBL's would work, though BP boxes can be tricky due to sensitivity to parameter values.

It's not clear what exactly need help with.

 

[iH8usrnames]

You are correct, horrible title - I'll update it after this response.

Where do I need help?
- I have very little knowledge of drivers, driver selection, or design parameters for a complex cabinet.
- Is bandpass really the best application or are there other designs to consider that would be easier to execute?
- I initially thought some sort of manifold (two drivers feeding a chamber ported through the wall) type setup would be good but fear a large cutout would be required in the crawlspace wall; I would like to keep the cutout under 192 square inches.

What are reasonable drivers for this project? I assume aluminum or CF with rubber surround due to changing seasons.
What are reasonable driver parameters for bandpass?
Are there any drivers known for use in bandpass cabinets?
1x18", 2x15" or 2x12" reasonable?

I assume, if the design calls for a 12" long 4" diameter port - and that port is on the exterior of the front chamber, I should subtract the volume of the port from the front chamber?

 

[BassThatHz]

I'm surprised they haven't complained of the noise yet.

Do you never get any wind there or only setup the screen during movie-night?

In any case, I'd probably go with a pair of PA-460's ported to 30hz and place them directly behind your seating.
That's the only way to get sufficient bass without killing the bank or frying small animals at a distance.
Those drivers are so efficient that amplification could literally be anything, but an nu1000dsp is the best match (parallel 4-ohms).

 

[iH8usrnames]

Currently using my Elac UB5 for sound - hauling them in and out each night. My neighbors seem to live with their blinds closed and air conditioning on; so far no complaints. I've even asked them and they are fine. Obviously, no bass from the Elacs.

It takes less than 15 minutes to completely setup the screen. In total, about 40 minutes to have everything completely dialed in. I can put it all away in roughly 15 minutes. Next year I will have something better for the screen setup and the speakers will all be installed.

The crawlspace is directly behind the seating area, so that is covered.

I like the $90 speaker, but would they work in some sort of Bandpass cabinet?

 

[iH8usrnames]

If I could I would delete this thread and start over. I should be more to the point in the future.

 

[buggers]

I have to say I am having a hard time discerning exactly what it is you are trying to do. What is the exact budget? What are the exact dimensions of this crawl space? Are we building a sub or mains speakers?

 

[iH8usrnames]

I have to say I am having a hard time discerning exactly what it is you are trying to do. What is the exact budget? What are the exact dimensions of this crawl space? Are we building a sub or mains speakers?

Thus, I would love to delete this thread and start over.

Location information:
- Patio is located at the back of the house where I have an addition.
- The addition has a large crawlspace with concrete floor and considered a "conditioned space" (it gets some heat and AC in the space).
- The crawlspace is 12'x24' with 40" high ceiling (quite roomy).
- I do have neighbors roughly 15' either side of my house. For this reason I would like to limit the sub to 30hz and above - actually 40hz+ would be just fine, I am sure.

Parameters
- I would like a sub located in the crawlspace to deliver sound to the patio through the crawlspace wall.
- I would prefer not to cut 18" holes in the walls.
- I imagine a 4th order bandpass cabinet may be a good fit; the wall penetrations would be limited to the diameter of the ports.
- As noted above I have neighbors, no need to reach 130db at 35hz. Though, I would like to some headroom to protect the drivers from extreme dynamics.
- I imagine crossing over to the sub somewhere between 60-80hz.
- I am not trying to create a high fidelity THX experience, just want something decent with a bit of bottom end.

I am open to:
- single or multiple cabinets.
- single or multiple drivers per cabinet.
- 12", 15" or 18" drivers.
- I mentioned 4th order band pass but open to other ideas so long as it does not result in a large hole in the wall or placing cabinets on the patio.
- If possible I would like to limit the cost of drivers to $400 total, $500 may be something I could swing.


I initially thought of some sort of manifold IB cabinet but figured that would require something like a 10"x17" hole in the wall.

I am totally open to suggestions and would be wildly appreciative of somebody leading me by the nose through the process.

 

[noah katz]

... I would like to limit the sub to 30hz and above - actually 40hz+ would be just fine, I am sure.

In that case, why not save yourself a lot of trouble and get some PA speakers for L and R.

 

[asarose247]

Behringer Eurolive B112D 1000W 12" Powered Speaker

https://www.sweetwater.com/store/de...-eurolive-b112d-1000w-12-inch-powered-speaker

 

[notfastenough]

Although 21" is all the rage, I believe the PA modeled pretty good in the Devastator. Have you checked that thread? I'd opt away from all of the others since they'd be larger and lower tuned.

I'm pretty sure this exact application was the intended use in the first place.

 

[iH8usrnames]

In that case, why not save yourself a lot of trouble and get some PA speakers for L and R.

I am 50 years old and have no desire to haul out big stupid speakers and run 120v and audio cables to them when I want to watch a movie.

This has happened several times now, I come with a specific question and I get responses that has NOTHING to do with the question.
I already specified I am going to install small sealed all weather speakers, so how is suggesting five large PA speakers even in the ball park of my question?

 

[iH8usrnames]

Although 21" is all the rage, I believe the PA modeled pretty good in the Devastator. Have you checked that thread? I'd opt away from all of the others since they'd be larger and lower tuned.

I'm pretty sure this exact application was the intended use in the first place.

Are you referring to the PA 460? I fiddled with that in WinISD for a few minutes but nothing extensive.

I am not aware of the "Devastator". I will look for it.

 

[noah katz]

I already specified I am going to install small sealed all weather speakers, so how is suggesting five large PA speakers even in the ball park of my question?

You're also having some trouble reading; I suggested PA only for L/R, which saves you a lot of time and expense not dealing with subs, but I take your point.

For your requirements they may not need to be that big, but I guess you want to keep them very small?

Another benefit of PA is that the directivity will keep the sound more contained, and require less bass because it will be closer to the listening area.

 

[notfastenough]

Are you referring to the PA 460? I fiddled with that in WinISD for a few minutes but nothing extensive.

I am not aware of the "Devastator". I will look for it.

And honestly, if you're not looking for oodles of output, you could probably scale it down to a 15" Dayton PA driver. However, it would require being modeled again in Hornresp/WINisd and the layout redone accordingly.

 

[iH8usrnames]

I just worked over the PA460 again and it is extremely promising, and cheap.

I am not against having the ability to create obscene bass, its not my motivation. The way I see it, if the cabinet can produce 115db and I never use it over 100db, that is a safety margin.

I will see how the 12 and 15" drivers model later tonight.

Screen caps from WinISD included.

 

[iH8usrnames]

You're also having some trouble reading; I suggested PA only for L/R, which saves you a lot of time and expense not dealing with subs, but I take your point.

For your requirements they may not need to be that big, but I guess you want to keep them very small?

Another benefit of PA is that the directivity will keep the sound more contained, and require less bass because it will be closer to the listening area.

I stand correct, you did specify L&R. either way, I am not interested in hauling big boxes around. I would like this to be as simple to use as possible so my wife does not need me to set everything up each time. Everything will be hardwired in place 24x7.

Also, I apologize. Work has been a melt down today and I have a bit of misdirected anger. FYI, never use AT&T for MPLS; our circuit has been down all day and we've been getting the run around with them.

 

[BassThatHz]

I would not use the PA-460 in a bandpass box.
In fact I wouldn't use bandpass at all... they tend to have horrible sound quality.

Just stick with ported, the PA-460 can be ran up to 300hz.
Mid-bass is 50-300hz, which is the frequencies you "feel in your chest".

 

[BassThatHz]

I have a bit of misdirected anger. FYI, never use AT&T for MPLS; our circuit has been down all day and we've been getting the run around with them.

I guess we are fairly lucky where I work, their internet is within the same optical cable as the inter-city 911 service, a dedicated strand all the way back to the ISP's main data center, which has UPS's and generators. (and so do we).

I don't ever recall it having any downtime for years now, but if it ever has it was sub-second only.
and in case the physical wire gets cut, it automatically switches to wireless air-fiber. Fancy pants stuff batman...

 

[iH8usrnames]

I guess we are fairly lucky where I work, their internet is within the same optical cable as the inter-city 911 service, a dedicated strand all the way back to the ISP's main data center, which has UPS's and generators. (and so do we).

AT&T MPLS circuit lost loads of routes and AT&T being AT&T, it took several hours to even get in contact with the correct department to get help. We would open a ticket and they would reply, "Circuit is up, closing ticket". WTF! IT IS NOT THE CIRCUIT DUMMIES, ITS YOUR ROUTES!