Another DIY Infinite baffle idea?

Mark Ward

Active Member
During a chat yesterday about how to get VERY deep bass into my room, Nathan (NFordEnfield) came up with what appears to be stunning idea for an infinite baffle sub.

The Chimney

I don't have space beneath the floor and the ceiling is vaulted. The fireplace isn't needed at all and it wouldn't be too difficult to put a cover on the top that would allow air but not allow rain in.

Any immediate problems spring to mind here? If not where do I go from here? I'm thinking of this as a supplement rather than a replacement for a pair of hefty subs. The room's volume is 12,500 cubic ft.

I just measured the opening and I could comfortably fit up to a 24" driver in there :D

Any thoughts from you DIY sub makers out there? :)


Mark Grant

Novice Member
Great idea - using the whole of Kent as an infinite baffle !

The biggest problem I can see is that thunder heading up that chimney is going to trigger lightning storms all over Kent :D

I would probably suggest the Adire Maelstrom 18inch driver, never used one yet though, only because I have researched this for a planned house extension next year, that will have infinite baffle subs, vented into roof space and other rooms of the house.

That chimney would need sealing up anyway, otherwise you would lose some bass up there, so sealing it with a huge driver is a fab idea.
( an open chimney is like leaving a door open )

That room still looks a mess, thought the project was underway ;)


Mark Ward

Active Member
Hi Mark

Thanks for that, I'll certainly consider blocking the chimney completely. I'm going to have to do a search on all these DIY sub sites to gain some knowledge. The good thing about this is it'll wait, it won't hold up my target of getting the the room for Christmas.

That room still looks a mess, thought the project was underway
It's an old photo, it was the only one I could find quickly that showed the fireplace.

Room is underway. Waiting on tradesmen right now. Electrician mainly but I'm also waiting for a quote on plastering/decorating too. Still, doing the bits I can :)

Biggest problem I have right now is deciding what kit will end up in the room. I've quite a few options open to me right now.



I see two potential problems with the chimney solution.

1. Pipe resonance due to the length of the chimney."pipe+resonance"&hl=en&ie=UTF-8

2. Poor performance due to the location in the center of the room.

It's been a while since I've seen this photo, I'd forgotten just how big your room was. In short, you're going to need some serious bass drivers to fill that room, using a commercial sub is going to cost you a packet (you'll probably need 4 Servo 15's).

It looks like an IB is a non-starter in this room with the exception of mounting drivers in the wall dividing the two rooms, assuming you will be fitting doors across the opening. Even then it wouldn't be too good with the drivers behind you (I assume the main speakers will be in the position where the photo was taken from).

If you are keen to try DIY (and save a packet!) then I would look at a good vented sub (or two) in the corner behind the main speakers. It's tempting to think about putting another sub in the other corner but the width of your room is such that cancellation may be a problem, defeating the object.

Have a read of the Home Theatre forum to get some ideas for a vented design.

Here's something to get you started!


Active Member
I agree with GaryG you will need some powerfull subs to fill that room a pair EBS Alignment Tempests and some decient amplification should bee a good start.

see two potential problems with the chimney solution.

I see a third........far too much soot !!!!!!!!

Mark....How's the room coming along?

Still going SVS?...or is it Servo 15 time?


Mark Ward

Active Member
Thanks for your replies. I have to say I thought it wouldn't be as easy as it first seemed to use the chimney. A great piece of lateral thinking by Nathan tho' :)
Mark....How's the room coming along?
Slowly I'd say... I've been busy buying secondhand kit lately and the building quotes from tradesmen seem extremely hard to extract, let alone get them to come and do the work.

I will be in the room by christmas, but that'll be with boards tacked over the windows and various carpet pieces spread over the floor.

I'm currently waiting on an electrician who is fitting 3 separate independent ring mains and a separate earthing system for the room.

I have my speaker cable tubing ready to run under the floor but need to decide final speaker positions before running that and that depends what speakers I end up with.
Still going SVS?...or is it Servo 15 time?
I'm still very likely to go SVS with 2 x 16-46 CS-Ultras into a Samson 1kW amp to start but I've been looking out for some second-hand servo15's too. I figure it would hurt to mix types until I can afford to go all SVS.

I'm currently running my KefTDM45B and Rel Strata II in my lounge but there's just not enough room for them in there. I'm currently eBaying the Kef which should give me a good start towards the SVS's

Biggest problem of all is the wife who seems to thing that the master bedroom and en-suite should take priority over a bigger HT room:confused:. Can't understand women's logic sometimes!:rolleyes:


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