[Shockabuku]

Hi all. I thought I'd start a new thread in the subs forum to detail my infinite baffle build that I've been covering in my DIY build thread (link in my sig). There don't seem to be very many IB builds here in the UK, so I hope this might be of interest to some of the bass heads on here .

No prizes for guessing that forum member Nimby put me onto the idea of infinite baffle sub designs. From there, I spent a lot of time scouring the Infinitely Baffled forums for builds ideas, and finally I'm now building my very own own monsters of sub-bass

.

1. The room
I'm nearing the end of converting the upper floor of a ~200 year-old detached barn into a dedicated home cinema. The room measures 31ft x 15ft x 14ft max (vaulted ceiling). Here's how the room started out...

..and here's how it's looking at approx 80% completed...

2. The subs
A room this size was always going to stuggle with "conventional" subs, and I really don't have the budget for 4 x PC-13s, so for about the price of a single PC-13, I'm building two IB enclosures, each of which will house two 18" Fi Audio IB specific drivers. Fi are pretty much the only company on the planet currently making IB specific drivers, and as such they're not the easiest things in the world to obtain! After a few months of trying, mine are finally on a boat from America, and are expected to arrive in the UK next week . You can see details of the drivers HERE.

[Shockabuku]

3. The manifolds
The ground floor of the barn is of course a similar size to the upper, with an approx 8ft ceiling. My plan is to mount the two manifolds to the ceiling of the ground floor, firing up into the cinema room. Obviously, this will involve cutting holes in the floor of the cinema room, which in fact is the next job on my list .

As of today, I've built the manifolds & other than some priming and painting, they're pretty much ready for the drivers. I'm following the recommended build from the Infinitely Baffled sub nerds, which involves a double-skin box, 18mm ply laminated to 18mm MDF.

Here are some images detailing the build process. First, putting the MDF panels together...

Ply panels going in...

MDF base in place...

Interior joints filled...

And here are the manifolds, awaiting some attention from a router...

Next comes the hole cutting. First, I marked out the widest point with a low budget compass...

A woodworker friend of the family came around with his router to help out. Here he's making a circle cutting jig...

Luckily we've had some respite from the rain today, so we could make the dust outside...

First a recess in the MDF, half an inch deep...

Next, change router bit & cut out a 16 3/4" hole through the MDF & Ply...

And here they are, all cut & sanded down...

They certainly weigh a lot less now, although that'll change when 64lbs worth of drivers are inserted into each manifold .
Here's a shot of the bottom of the barn, where the manifolds will be mounted...

The manifolds will be fixed to these beams. As you can see, they'll need a bit of sorting to get them nice & level, and I suspect some expanding foam will come in handy to ensure a good seal between back & front of the subs...

Fingers crossed, the subs should arrive next week sometime, and then the real fun starts. In between now & then, I need to think about cutting some holes in the floor .

[suniil]

Now that's something serious

Glad you picked the right choice of driver! Shame, I'm in discussion wtih Scott (FI Car audio) and thinking of getting the stuff in sea pallet to reduce the freight. We could have imported together

Anyways looking forward to see the progress pictures, and you would be the proud owner an IB with dual 18" drivers

[AngelEyes]

That barn is gorgeous, what a fantastic cinema room. Thanks so much for sharing and do keep it coming

Out of interest have you chosen your positions for the IBs? I assume at this stage you have some flexibility so it would be worth doing some calculations to get the best positions to avoid room modes... having said that the vaulted ceiling will probably inject a whole new dynamic, hopefully positive

What amps and EQ are you planning to use?

When can wee come round for a listen

Adam

[AngelEyes]

Originally Posted by suniil

Anyways looking forward to see the progress pictures, and you would be the proud owner an IB with dual 18" drivers

I think he will have 4 drivers in total, 2 in each enclosure, right?

[Russell.Williams]

Just when you thought it was safe to go out again.....

To echo Adams thoughts, what a fantastic room. Puts me in mind if the house we bid on and lost last year.

Originally Posted by AngelEyes

That barn is gorgeous, what a fantastic cinema room. Thanks so much for sharing and do keep it coming

Out of interest have you chosen your positions for the IBs? I assume at this stage you have some flexibility so it would be worth doing some calculations to get the best positions to avoid room modes... having said that the vaulted ceiling will probably inject a whole new dynamic, hopefully positive

Just what I was thinking. I'd have thought the quarter points were the place to start, but with so little actual wall, I'll bet it measures pretty damn well anyway. It would be easy enought to find out as a DF sub placed on the floor would be very close to mimicking the upward facing manifold. I'd certainly be interested to see how it measures currently.

I'm also interest to know why you settled on a 2x2, rather than 1x4 manifold.

Lucky sod.

Russell

[cribeiro]

Gorgeous!

I'd be worried about possible structural damages, though, if those beams are really 200 years old

[AngelEyes]

Originally Posted by cribeiro

Gorgeous!

I'd be worried about possible structural damages, though, if those beams are really 200 years old

They don't build em like they used to, I wouldn't give it a second thought

Also interested in the rest of the kit, it looks such a large space for those standmounts to fill, however I must confess I don't know what they are

I really am impressed with the project, this really epitomises Home Cinema for me, glorious building with bags of character and seriously mental kit

Very jealous

Adam

[suniil]

probably, for structural safety . I'm sure mark has borrowed nimby's brain too for 2x2

Originally Posted by russ.will

I'm also interest to know why you settled on a 2x2, rather than 1x4 manifold.

Yes, my bad reading!

Originally Posted by AngelEyes

I think he will have 4 drivers in total, 2 in each enclosure, right?

[Shockabuku]

Thanks guys, I'm certainly having fun with this part of the project . Regarding placement, I've done the "sub at the seating position, crawling on the floor" trick, and actually I found the room to be fairly flexible in this regard. I also have to consider the aesthetics of holes in the floor - and safety - I have a young daughter. So, they'll be located in between the main LR speakers and the centre speaker, which will keep things tidy.

I went for two manifolds of two drivers each, rather than 1x4 following some discussion on the Infinitely Baffled forum. There are potential issues with delay due to the drivers lower down the stack, but I don't think there's a lot to decide between the two really, but two just made more sense to be, and I think should provide more chance of an even sound signature for all listening positions. I also prefer the aesthetics of two smaller boxes, and my back was weeping at the thought of a single huge manifold with 4 drivers!

To be honest, I think the barn will definitely be the weak point in the whole setup...based on what I have read about similar IBs, I suspect I could do some damage if I turn the gain up a litle too much . I'm just hoping I can turn it up high enough to enjoy before things start breaking .

Ah yes, amplification. I have a T.Amp TA2400 MK-X, which will feed 1200w max into each manifold...

I also have a Behringer BFD which I'll be using with REW to calibrate the setup once installed.

The vaulted ceiling is indeed a bit of a head-scratcher, acoustically. Following a recommendation from a knowledgable forum member, I've done a load of acoustic panels to absorb some of the stray reflections up there. Obviously it won't have much if any effect on sub-bass, but in theory should improve the higher frequencies...

[AngelEyes]

Originally Posted by Shockabuku

Thanks guys, I'm certainly having fun with this part of the project . Regarding placement, I've done the "sub at the seating position, crawling on the floor" trick, and actually I found the room to be fairly flexible in this regard. I also have to consider the aesthetics of holes in the floor - and safety - I have a young daughter. So, they'll be located in between the main LR speakers and the centre speaker, which will keep things tidy.

I went for two manifolds of two drivers each, rather than 1x4 following some discussion on the Infinitely Baffled forum. There are potential issues with delay due to the drivers lower down the stack, but I don't think there's a lot to decide between the two really, but two just made more sense to be, and I think should provide more chance of an even sound signature for all listening positions. I also prefer the aesthetics of two smaller boxes, and my back was weeping at the thought of a single huge manifold with 4 drivers!

To be honest, I think the barn will definitely be the weak point in the whole setup...based on what I have read about similar IBs, I suspect I could do some damage if I turn the gain up a litle too much . I'm just hoping I can turn it up high enough to enjoy before things start breaking .

Ah yes, amplification. I have a T.Amp TA2400 MK-X, which will feed 1200w max into each manifold...

I also have a Behringer BFD which I'll be using with REW to calibrate the setup once installed.

The vaulted ceiling is indeed a bit of a head-scratcher, acoustically. Following a recommendation from a knowledgable forum member, I've done a load of acoustic panels to absorb some of the stray reflections up there. Obviously it won't have much if any effect on sub-bass, but in theory should improve the higher frequencies...

The crawling around 'myth' won't really tell you a great deal, so I would ignore any advice based on that little gem.

Room EQ wizard should be the order of the day along with Russells suggestion of using DF subs in the proposed locations to give some idea of room response.

It may sound like a 'faf' but all that effort in construction resulting in a hideous room response at the seating position will be a lot worse There is after all only so much a BFD can do to help.

From what I have gathered the vaulted ceiiling should actually help quite a bit but you won't actually know until you run some sweeps.

Not sure on your aesthetic tastes but there is nothing stopping using some sturdy grates/grills to cover the IB vents so they are safe to walk over. The only real issue you have to worry about then is how it impacts on the floor below

Adam

[Russell.Williams]

Originally Posted by AngelEyes

Also interested in the rest of the kit, it looks such a large space for those standmounts to fill, however I must confess I don't know what they are

Sonus Fabers mate. Beautifully crafted Italian speakers designed for the highest quality accurate reproduction. Nothing that would interest you then.

Russell

[AngelEyes]

I am guessing you have a Sony Projector there, and forgive my ignorance but 2.35:1 is the more common 'cinema' ratio right? Do you need an Anamorphic lens for that?

If I were to have a dedicated room I think I would opt for a true 'widescreen' option rather than 16:9. Any negative issues with this kind of setup?

Sorry for the questions, you ahve just rekindled my interest again

Adam

[AngelEyes]

Originally Posted by russ.will

Sonu Fabers mate. Beautifully crafted Italian speakers designed for the highest quality accurate reproduction. Nothing that would interest you then.

Russell

Silence wuffian

Don't tell anyone but I have been considering demoing some 'non' M&K speakers

Adam

[AngelEyes]

Originally Posted by russ.will

Sonus Fabers

They do look rather lovely, not the model you linked to though, these look front ported?

Adam

[eviljohn2]

Marvellous work - you're living the dream.

[Shockabuku]

Cheers fellas, I'll see what I can do about getting my mitts on the calibration kit from a mate of mine, just to make sure before I make those holes .

The speakers are indeed Sonus Fabers, but unfortunately not the lovely Cremona Auditor. Mine are the humble (well, if you can call £1200 for a set of speakers humble!!) Concerto Home, along with the matching Solo centre speaker. I did have the matching Walls (monopole side surround speakers) in my previous setup, but I fancied something more enveloping in this room, so bought some M&K 55MkII tripoles. The Walls are now hooked up to a tube amp and a Squeezebox in the living room, and sound rather nice . The Concertos aren't the most transparent speakers in the world, but I don't care because I think they sound just gorgeous, and are a pretty fine piece of furniture in their own right.

Regarding the projector, it's a Sony VW60, and yes I'm using a Prismasonic anamorphic lens. Most films these days are coming out in the wider aspect ratios...2.35:1 to 2.40:1, and having created this setup, I would never go back to 16:9 now. It's not cheap, and it's a bit fiddly to set up, but it is worth it imho if you don't exclusively watch older films, and you have the space.

[Shockabuku]

Originally Posted by suniil

Now that's something serious

Glad you picked the right choice of driver! Shame, I'm in discussion wtih Scott (FI Car audio) and thinking of getting the stuff in sea pallet to reduce the freight. We could have imported together

Anyways looking forward to see the progress pictures, and you would be the proud owner an IB with dual 18" drivers

Ah yeah, that's a shame, although you know there is a UK importer for Fi stuff? The price over here is of course MUCH higher than you'll pay in the 'States, but I guess shipping four 32lb drivers isn't going to be cheap!

[Russell.Williams]

Originally Posted by AngelEyes

They do look rather lovely, not the model you linked to though, these look front ported?

Adam

Have a look here. When I read in magazines about top quality fit and finish on speakers, I often wonder if they've ever met a pair of SFs - They make most stuff look DIY.

Russell

[AngelEyes]

Originally Posted by russ.will

Have a look here. When I read in magazines about top quality fit and finish on speakers, I often wonder if they've ever met a pair of SFs - They make most stuff look DIY.

Russell

I did have a Google earlier and have been drooling ever since, gorgeous furniture. Hiding in my M&K 'hole' has been a good way of stopping me spending any more money but when I poke my head out and see gorgeous things like that...

[AngelEyes]

Originally Posted by Shockabuku

Regarding the projector, it's a Sony VW60, and yes I'm using a Prismasonic anamorphic lens. Most films these days are coming out in the wider aspect ratios...2.35:1 to 2.40:1, and having created this setup, I would never go back to 16:9 now. It's not cheap, and it's a bit fiddly to set up, but it is worth it imho if you don't exclusively watch older films, and you have the space.

This is my thinking exactly, I do have some classic Japanese stuff in my collection and of course good old Star Trek but most is wider than 16:9 and I think I could live with the black bars on the sides of the odd 16:9 title.

Any rough guide to how much Anamorphic lenses and a wider screen adds to the average budget? I have been guessing around 50%, hopefully it isn't much more than that

Adam

[suniil]

Yeah, just saw it in your link! UK prices are not very high when you compare shipping & VAT.

BTW, TA2400 looks very good, please share your thoughts when everything put together.

Originally Posted by Shockabuku

Ah yeah, that's a shame, although you know there is a UK importer for Fi stuff? The price over here is of course MUCH higher than you'll pay in the 'States, but I guess shipping four 32lb drivers isn't going to be cheap!

[micb3rd]

Very cool, I read most of your room build thread, I look forward to seeing the results come to fruit.

[jason shep]

Thats going to be a stunning cinema

Shockabuku,i built an IB 6 months ago & it is the cleanest bass i have ever experienced,have fun

[Gregory]

Originally Posted by AngelEyes

Not sure on your aesthetic tastes but there is nothing stopping using some sturdy grates/grills to cover the IB vents so they are safe to walk over. The only real issue you have to worry about then is how it impacts on the floor below
Adam

I had a similar issue with an IB I built into the floor. After much (failed) faffing about looking for grilles that were solid enough, but with mostly open area, I've hit on getting a grill made from 10mm stainless steel by bespoke waterjet cutting - allows me to get the size exactly right, make it strong but mostly open air and fit with the rest of the decor. Your area is bigger, but you can get waterjet cut panels up to about 25mm thick, so I'd have thought you could make it tough enough to park a car on (never miond a small child). If you can create a CAD drawing of what you want then getting it made is a doddle

Does remind me that I never got round to recalibrating the BFD after finishing!

Love the project BTW

Cheers

Greg

[Shockabuku]

Hi again all. Finally got around to fixing the manifolds in place today. I've also posted this in my build thread, but I want to keep this thread alive just for the sub build too.

About to cut a big hole in my barn...

The jigsaw blade wasn't quite deep enough for all three layers of flooring...

...which meant it was handsaw time. Talk about sweating buckets...

The result, two holes :o...

Next up, mounting the manifolds. Closed-cell foam (as the American's would call it, or "pipe lagging" to you and me) over the edges of the manifolds to ensure a nice seal...

My car jack came in handy to lift the rather hefty manifolds into place...

Here's the foam compressed & trimmed. A lot easier than filling all the gaps after the fact with expanding foam...

We've used various tie plates & brackets to keep them in place. Probably overkill, but then so are four 18" subs . I actually swung on one of these, so I'm happy they'll do...

Next up, we cut some ply panels to fill the gaps either end of the manifold. These panels fix to batons screwed into the joists...

The end result for today...

I still need to fill a few gaps here & there to ensure a good separation between front & back of the subs, and tidy up the holes, but I'm quite happy with the progress for today . Unfortunately, the actual subs still haven't arrived (13 weeks and counting!!). Seems that the shipment was tampered with, and one of the subs was stolen, along with a number of other items . The UK distributor for Fi has been as helpful as they can be, and arranged for a replacement to be shipped over by air freight. Unfortunately, that turned out to be the wrong model , so hopefully another one will be arriving next week. I'm really hoping to get them all installed next weekend, so fingers crossed they get to me in time.

[t72bogie]

now that looks like you are going to have some awesome bass in there

I live in a barn, my living room is even 'worse' than that to fill - 50 x 19 x 20ft vaulted ceiling and I can remember just before I moved in, playing around on the Velodyne website with the sub configurator thing and it telling me I needed 2 of their signature 18's at £10K a pop to fill the room volume

Well, of course I didnt want to spend that much on subs alone, and had just picked up a single, used DD15 off the forums, so thought I would give that a go for a start....well all I can say is, I havnt bought another one yet ...sure, I havnt got bass that shakes the foundations, but you can feel it in your chest still in the listening area (a 13ft x 19ft area in the middle of the room). It fills out the bottom end nicely and after a few days tinkering, Ive got a nice flat in-room response ...well up to about 120Hz for sure

Now what its going to be like in a smaller space, with 4 x 18s ...WOW that should be good and be able to really shake those beams

Have you thought about any structural sound deadening too? ...maybe on the underside of the floor? ...Im just thinking all that floor is gonna be moving like a good un ..mine was - ended up decoupling the sub from the floor as the floor resonating and loose bits rattling wasnt what I wanted to hear in my movies !

[Shockabuku]

Originally Posted by t72bogie

Have you thought about any structural sound deadening too? ...maybe on the underside of the floor? ...Im just thinking all that floor is gonna be moving like a good un ..mine was - ended up decoupling the sub from the floor as the floor resonating and loose bits rattling wasnt what I wanted to hear in my movies !

Thanks for the comments . Yes, I have been thinking a LOT about how the floor is going to cope with these subs...and I am expecting to have to spend rather a long time stiffening the boards at the very least. I figure my best bet is to get it all set up and see what needs doing, rather than spend too much time on it at the outset. I have visions of the floorboards doing a mexican wave down the room, but hopefully it won't be that extreme .

[t72bogie]

...mine was easy as its just a single sub mounted on the suspended wood floor - some auralex foam and a granite paving slab did the trick

Looking at your barn I think you are right - see what its like first and how much the floor is jumping ...and then whether you need to go as far as a new timber floor on top with sound barrier mat inbetween, or just some localised bracing ...still...a nice problem to have I guess

[Shockabuku]

Originally Posted by t72bogie

...still...a nice problem to have I guess

yeah, I've had worse