Subwoofer inside the wall considerations.

[kdb313]

After calibrating subwoofer placement, I found the best place for my sub is on a shelf to the right of my front right speaker. The shelf is a built-in framed and sheet rocked return air cabinet and is 40 inches high,26 inches wide and about 60 inches long. With a little bit of modification I am considering putting my full size 12 inch ported subwoofer inside of the cabinet. The front of the cabinet is sheet rock, I am planning on cutting a circle so to expose the driver and covering it with a speaker grill. Before I put my reciprocationg saw to work is there anything else I need to consider?

 

[WallisH]

I am about to put two new subs (Rythmik F12s) inside a built-in cabinet, and here are the comments that people have generally given me:

1. Most importantly, most people who weighed in think that putting a sub inside another enclosure is an awful idea that will interfere with the sound, create rattling, etc. I am fairly nervous about doing it, but have no choice due to WAF factors. So I would be a little hesitant to voluntarily select in-cabinet installation.

2. With that said, none of the manufacturers I talked to said that it would not work (I spoke to HSU, SVS, eD, and Rythmik). eD had more hesitation than anyone, saying that while it probably would be fine, you wouldn't know how it sounded until you actually got it installed. On the other end of the spectrum, HSU's owner's manual for the ULS-15 actually says that you can place it inside a cabinet.

3. Some people said you have to worry about overheating because of the amps. Neither eD nor Rythmik were particularly concerned about this, though. They said that in the abstract, you might be better off with a fan. But they didn't think it was absolutely necessary. If I'm understanding your cabinet dimensions, that doesn't sound like it will be an issue for you.

4. On a related issue, I was seeing contradictory advice on the size of the enclosure. Some people recommend having an enclosure that is only slightly larger than the sub; this supposedly helps with the sound quality. Other people said I needed several inches of room on each side to reduce the risk of overheating. I don't know what advice is correct.

5. One of the manufacturers said that if you are installing inside a cabinet, you should try to have the sub centered inside the cabinet.

6. I am going with Rythmik F12s. I asked the owner (Brian Ding) yesterday whether I could benefit from using Gramma isolation risers, acoustic dampening materials on the cabinet walls, or something like Rockwool to minimize the acoustic side effects. He didn't think any of those were necessary, FWIW.

7. What type of grill are you going with? I'm probably going with the 3/16 grill from this place: http://www.reliablehardware.com/customspeakergrill-316diastaggered.aspx

8. People also talked about the stoutness of the cabinet (less stout=more rattling). Some people even said that to minimize vibration one should cut out the bottom of the cabinet and have the subwoofer resting directly on the ground.

As you can tell by my post count, I am somewhat of a newbie, so I don't pretend to have all the answers.

 

[kdb313]

Great information, thanks for the feedback.

The main concerns seem to be:

1. The stoutness of the enclosure. My enclosure is frame and sheet rock, it seems very rigid and well put together. I could add some bracing if needed.

2. Overheating. I can see that this could be a problem. I am hoping that the size of my cabinet will help, if needed I could install a small fan to keep the air circulating.

3. The size of the enclosure. This is the hard part. I was planning on building just a shelf inside the cabinet and putting the sub. on the shelf. I do have the room to build an enclosure to house the sub. if needed. But if I put the sub inside an enclosure, air circulation becomes a problem. I think this is going to be the trial and error part. Luckily, I have the room to be flexible here.

One of my limitaions is what you mentioned in #8, there is some plumbing in the bottom of my cabinet and I cannot put the sub directly on the ground, it is going to have to be suspended. I am planning on putting some acoustic foam on the shelf under the sub. Do you think this will help?

As far as my grill, I was looking at a couple of different options.
1. Cutting out a grill frame using MDF and covering it with speaker cloth.
2. Using the grill that came with my subwoofer.
Once I get the sub in place I will explore the options that will please everyone.

Thanks, Reliable Hardware gives me some more options. The 1/16 Dia. Staggered White speaker grill looks good too.

Any more considerations are welcomed.

 

[WallisH]

Great information, thanks for the feedback.

The main concerns seem to be:

1. The stoutness of the enclosure. My enclosure is frame and sheet rock, it seems very rigid and well put together. I could add some bracing if needed.

2. Overheating. I can see that this could be a problem. I am hoping that the size of my cabinet will help, if needed I could install a small fan to keep the air circulating.

3. The size of the enclosure. This is the hard part. I was planning on building just a shelf inside the cabinet and putting the sub. on the shelf. I do have the room to build an enclosure to house the sub. if needed. But if I put the sub inside an enclosure, air circulation becomes a problem. I think this is going to be the trial and error part. Luckily, I have the room to be flexible here.

One of my limitaions is what you mentioned in #8, there is some plumbing in the bottom of my cabinet and I cannot put the sub directly on the ground, it is going to have to be suspended. I am planning on putting some acoustic foam on the shelf under the sub. Do you think this will help?

As far as my grill, I was looking at a couple of different options.
1. Cutting out a grill frame using MDF and covering it with speaker cloth.
2. Using the grill that came with my subwoofer.
Once I get the sub in place I will explore the options that will please everyone.

Thanks, Reliable Hardware gives me some more options. The 1/16 Dia. Staggered White speaker grill looks good too.

Any more considerations are welcomed.

1. That sounds like it will be fine.

2. Fans are fairly easy to find and install. They are also fairly inexpensive. Here are some that I found: http://www.blowerwheel.com/fans-cooling-electronics-framed-square.htm.

3. I don't know if acoustical foam will help. I had been focusing on isolation risers (the Gramma riser or the new one that eD is selling). Rythmik's owner said that he did not think that would significantly help in my enclosure. I also asked him about acoustic foam, and he said that it does not really help, as those foams don't really absorb the low-Hz soundwaves that a subwoofer generates.