Howdy,

So I have been planning on a DIY sub for some time now, and since I now have the M60's/VP150 I have started to move ahead. The reason I am going with a DIY is two fold: 1) my girlfriend was very accommodating with the M60's acquisition, and I am trying to decrease the visible footprint of my audio/visual equipment. 2) the new apartment I am moving into in August is your typical small NYC apartment, so everything is multifunctional.

So the sub cabinet will also function as my TV stand. I realize this limits my sub placement, but that's life and it's a compromise I can live with. I was planning on a dual 15" Rythmik sealed enclosure, but having gone through the planning I am now leaning more towards dual 12" Rythmiks instead (with 600watt servo amp).

Here is the crazy part. I also am planning on building an upper cabinet which will enclose the VP150 above the sub cabinet. In terms of structural security I am not worried, but I am worried that having the center channel so close to the foward firing subs might cause some interference or degradation of sound. Is this true? Also, this is still early in the planning phase so I welcome all and any comments.

Please see the images at the link below for a better idea of the setup. I also have a SketchUp file if anyone wants to take a closer look. Note that the image uses the 15" woofers, and I have not put holes in the braces to allow air passage (yet, but I will). Also the leg pegs are missing. The woman is 5'6" for comparison.

http://picasaweb.google.com/sam.golden/SubwooferCabinet?feat=directlink

Thanks,
Sam

At one time I had planned to build a special shelf to sit my VP150 on top of my horizontal EP600. Axiom recommended I do not do this, not because of any sound issues, but vibration issues from the sub.

I would be more concerned about how this will affect your TV, not a good thing.

Hi Sam,

I really like the technology and value of the Rythmik subs, too. I'd like to build one or two someday.

I must say, I'm with Randy on this deal. The subs are going to vibrate A LOT. Unless you can think of some way to effectively decouple the sub cabinet from the VP150 cabinet, I think you're asking for trouble with both the center channel and especially the TV.

You might be able to mitigate some of the vibration by configuring the subs in a push-pull arrangement instead. I'd check with Brian at Rythmik to see about that.

However, given your situation, I'd probably mount the TV and the VP150 on the wall and build two, separate small sealed sub boxes that you could stash under an end table or something. Or reconfigure the sub array so that it IS an end table.

Yeah, that was another concern of mine as well. I was considering making the top cabinet out of a very hard wood, and placing some dampening materials between the two. And using the sand fill method to significantly weigh down the sub and reduce vibrations (ie, build a section on top of the lower cabinet about 5 inches in height that is filled with sand). Forward firing the subs should also reduce any vertical vibrations.

You all may be correct though, and wall mounting the TV and VP150 may be best. Eitherway this cabinet has to look like/perform as counter of some sort, so this may be a trial by error deal hah.

For people who have a EP800, what are the vibrations like with that beast?

- Sam

You're looking at dual 12" subs when you're moving into a small NYC apartment?

The neighbors are going to love him.

Haha, yes, it's more of a investment/future situation. I have a good idea of what I want for after the apartment, and I'd prefer to build once while I have the time and enthusiasm (and money).

I have spoken to a few manufaturers of various dampening materials, and the general consensus is that it is doable with enough layers.

Hello Golden,

I keep a small New York City apartment and use an EP500 as an end table at one end of my couch. However, when I purchased the apartment, I intentionally bought on the main floor of the building (the room with the elevator motors is underneath me). No apartment except the one above me shares any common wall. No complaints so far.

By the way, using forward-firing subwoofers will not in any way lessen the potential transmission of acoustical and mechanical vibration through the building structure. Deep bass below 100 Hz is essentially non-directional. It radiates in every direction from a subwoofer, which is really a big, low-frequency air-pressure pump. How those pressure waves interact with the walls, floor and ceiling as well as the framework of the building can't easily be predicted.

Like others here, I would have reservations about using the subwoofer as a TV stand.

Regards,

Alan

So, Alan, when you have guests in NY, do you ask: "Do you prefer your Martini shaken, stirred or subwoofered?"

I came across this article yesterday which somewhat has to do with your original question. I can only imagine what the researchers would have to say about using a subwoofer as the TV stand

ha, ha! No, Eric, I have the cocktail shaker welded to a custom butt-shaker driven by the subwoofer output. . .

Cheers,

Alan

This is all very informative. I think the direction I may take is to build the dual enclosure as if it could be a functional surface and incorporate as much vibration dampening as possible. And then if it is not at the level required, it becomes a girlfriend-friendly countertop... with wall mounted center channel and TV above.

Priority will be to err on the side of caution, and not destroy my electronics. Like the thread says: crazy idea! haha. At the moment, child safety is a lesser concern... although dog safety is also high on the list.

Still welcoming input, the more the merrier.

- Sam

I have sort of a similar situation developing, but not exactly. In my livingroom I built a small room (6 1/2 feet wide by 3 foot deep) to house all of my DVD's, CD's and loose wire. My 65 inch TV hangs on the outer wall, and all my electronics (reciever, DVD player, dual computers, etc...) are built into a cabinet over the TV. At the very bottom of the 'closet' is a rectangular cut-out where the EP800 will sit. The subwoofer will be inside the room facing out. It will not be attatched to the walls at all, but I am very curious as to how much vibration it's going to create. The walls are very sturdy, so I'm not worried at all about the thing falling apart or anything like that, but I do wonder if I'm going to be constantly picking up movies off the floor everytime I turn the music on. I also wonder if the vibrations will effect the TV at all? It weighs a good 120 pounds, so it's fairly solid, but the power of the 800 may just prove a bit inconvenient at times... we'll see.

I'm already plannning on having to reinforce parts of the wall once I get the EP800 in there and working it's magic. It will be a learning curve I'm sure. But what would life be without trial and error fun times such as these???

I take my martini igredients to the hardware store and ask them to put them in a paint can shaker.

I think they likely will but I don’t think proximity to the EP800 will be as important as volume as long as there isn’t any direct contact. When I first set up my EP500 I misread the instructions and set the volume to high. The second the test tone started playing windows, dishes and something inside of my DLP sitting across the room started rattling.

Lol, yes those rascally subwoofers do tend to 'shake things up' around the house don't they. At my old house where my HT was in my basement, whenever I'd play a movie or some music it was absolute chaos upstairs! And this was with a single 15 inch 210 watt downfiring Cerwin Vega subwoofer running things. It was positioned directly behind the couch, and sitting 3 feet away from it the bass output seemed very level and integrated into the system. However the basement seemed to act like an amplifier, and upstairs it sounded like I had crazy levels of bass cranked up to MAX XXX!!! The dishes, pictures, silverware... anything that wasn't nailed down upstairs would rattle and shake like there was a level 8 earthquake going on.

I'm sort of curious as to whether or not having the EP800 sitting inside of this closet will create the same amplification effect? After all this monster uses dual 12 inch woofers and an 800 watt amplifier to move them. But I'm thinking the sealed nature of the EP800 will cut down on this some. Otherwise, I may have to turn it down to zero!!!

Alright, now I have some questions.

Essentially, Rythmik is out of dual DS1200 drivers (their metal 12" woofers) and only has the GR 12" paper cone dual drivers. Admittedly, I know very little about the more intricate differences between the two cone types. I do realize that the GR drivers extend higher better, and require less power to drive due to their lesser weight.

However, most of the music I listen to is not bass heavy. The films I watch are generally very very bass heavy. Will I be loosing kick in the HT scenario by going with the GR's?

On the music side, I actually like that the GR's extend higher, it should really fill out the low end of the music I listen too. Hell, there may even be significant bass in it, I just never would have noticed before, lol.

What have your experiences been with paper vs metal drivers, specific to subs? Any input would be great.

Oh yeah, the other thing I like about the GR's are that they are a lot cheaper and can run off the smaller amp equally well to the DS12's.

- Sam

Have you considered any other drivers? There are some very very good drivers out there. Creative Sound Solutions makes a very linear 15".

You might want to check out Home Theater Shack's DIY Subwoofer forums.

Elemental Designs also sells some very good drivers.

I'm not gonna lie, I very much like the idea of the servo technology. Especially due to the somewhat restricted size/space issues this DIY project will entail. I am also limiting myself to 12" drivers for the same reason.

That said, since this has already become more complicated than I had hoped, I am all ears to other driver's as well. I'll take a look at the ones suggested above.

Of course, by the time I decide on a final design, this could very well be a single 18" woofer design, haha.

Yeah, make it 18 so it's legal.

Take it from Charles. He learned the hard way that 15 will get you 20!

Prison cell acoustics are no picnic, either. I had to dismember my cellmate and use him as acoustical treatments.

If it was me moving into an apartment I would get a Paradigm DSP 3100. It is small, sounds great and shouldn't bother the neighbors too much.

Charles Hannibal V.
You have to work with the materials at hand. Good for you.

Sam. I would strongly recommend making the visit to homwtheatershack. There are lots of very experienced DIYers that can help you sort through all the design stuff and there is a great program, winisd, for modeling drivers.

There are a couple of guys on the forum who will help you with the modeling. All you need it the T/S parameters of the drivers you are considering. this will allow you to compare the performance of drivers given your restrictions.

Here is an example of the type of resource the shack is. Its a build thread for an 18" Mal-x with passive radiators: massive output in a reasonably sized package.

Yeah, I have been frequenting HTShack, AVS, etc for a while now. I don't think I would be attempting this if I hadn't been silently been observing the amazing work, and feedback, of others. Thankfully the modeling is pretty straight forward with a sealed enclosure and I've already worked the numbers out.

The paper drivers present an interesting option. They have lower SPL at high power than metal drivers, and require less power (370watt rather than 600watt), resulting in a tad less overall vibration. Considering for the immediate future I will not be pushing the sub tremendously hard, I am tempted to see if this idea may work (not the TV part, just the mounting the VP150 in a connected vibration-dampened upper compartment). The design is modular, so the worst case scenario is simply a dual 12" driver setup, with a wall mounted VP150 above... I can live with that