Putting gear into walls, need to rebuild midQ kappa enclosure!

[Guiria]

I am redoing my bonus room, ditching an entertainment center, and putting all audio equipment, speakers, subwoofer into the walls. My bonus room has 24" joists on center leaving about 21.5 inch shelving width after sheet rock. Problem here is my current midQ Kappa subwoofer will not fit and I need to rebuild it into something that will fit.

There is a high probability that we will be moving a few times over the next 4 years so a bigger box is definitely out, and I'm leaning to a smaller sealed box for the time being, but I'm not convinced entirely to go small and sealed just yet.

My thoughts have been the following, all amp limited at the moment to 600 watts @ 4 ohms, or 300 @ 2 ohms stereo, stable:

-Do I rebuild the kappa sub into something narrower and taller to fit the space
-Do I heed my wife's suggestions building it sealed so it is smaller and easier to access the storage behind the sub?
-If going sealed do I sell the Kappa and try to get into a better sealed sub for roughly 2 cubic feet and 600 watts, budget limited...maybe could squeeze a shiva-x out but nothing more than that.
-I can buy a pair of gently used RSSHF15's from a friend for around 200. Since I will have a wall cubby flanking both sides of the TV I could build dual 2 cubic foot boxes for the 12" Dayton.

I'm on the fence at this point but I need to get the ball rolling because my bonus room is also my kids playroom and right now in its disarray my kids will drive me nuts until that room is finished again.

 

[Rickster71]

Why not re-frame the opening to the size you want?

 

[Guiria]

The joists are part of an engineered truss system that allow me to have a 3 car garage without any support beams in the garage. Every board in the truss is either under compression or tension so I don't want to modify anything to maintain structural integrity of the room.

Short answer is I could probably modify a couple joists if I wanted to but I'd rather not

 

[Rickster71]

There is a high probability that we will be moving a few times over the next 4 years

Just a thought.
Wonder if it's worth doing all the built-in work if you'll be moving?

 

[Guiria]

Just a thought.
Wonder if it's worth doing all the built-in work if you'll be moving?

Yes, I ask myself that question a lot lately

My wife is pregnant and we currently have a spare room as an office. All the office furniture is coming into our bonus room to make way for the new baby's room. To minimize floor space consumption we are putting all the AV gear into the walls and because of the attic space behind the walls, the cubby's are about 4.5 ft deep at their deepest part so we'll be adding some storage space as well.

Lot's of work but I won't start moving until Fall 2012, so I'll have a couple of years to enjoy it!

 

[GO-NAD!]

I don't know which would work better - the kappa or dual Daytons, but I think you have lots of room to do in-wall. How about PM-ing Annunaki? He's done in-walls and in-ceilings. He also helped me design my dual in-ceilings, which I'm very happy with.

 

[Guiria]

Old layout

New layout

The cubby on the left from the ground to the first shelf will be where the subwoofer needs to fit which is about 27 inches tall. The space is roughly 21 inches wide and actually quite deep at 54"...I guess I could build something narrow and long.

So far I've tossed around the following:

rebuild kappa into either sealed or slot vented
build a Dayton rss390HF sealed
Thought about saving up a little for something like the AE AV15-X but at that price the driver selection really opens up...
build a couple ported 10" subs and stuff them both in the left cubby
build a couple 8" subs and put them in stereo mode, one on each lower shelf in a box 14x15x14 next to my bookshelf speaker. That would leave the cubby open for kids to play (although they have a free cubby on the other side, this one is technically mine).

Haven't yet decided.

I need to get a real camera in there and take some clear pictures...cell phone camera's suck unless you have lots of good natural lighting.

 

[annunaki]

You have a lot of space available there. The kappa in a rebuilt enclosure will offer the least expensive option.You could create a facade or fascia panel to give it a built in look as well. I would definitely stay vented however.

If you are set on a new woofer, well then it will depend on whether the optimal enclosure will fit with your woofer choice and budget.

 

[Guiria]

You have a lot of space available there. The kappa in a rebuilt enclosure will offer the least expensive option.You could create a facade or fascia panel to give it a built in look as well. I would definitely stay vented however.

If you are set on a new woofer, well then it will depend on whether the optimal enclosure will fit with your woofer choice and budget.

There is a lot of space there I agree. I think the biggest hang up I have is the DIY itch, The kappa perfect really isn't lacking in performance, I'd just like to try something new and different...

I may stick with the Kappa, not sure though.

Current parameters I am working with for a new driver are the restraints of current equipment being:

BFD
600 watt amp
harrison labs FMOD 20 Hz HP filters if needed

 

[annunaki]

There is a lot of space there I agree. I think the biggest hang up I have is the DIY itch, The kappa perfect really isn't lacking in performance, I'd just like to try something new and different...

I may stick with the Kappa, not sure though.

Current parameters I am working with for a new driver are the restraints of current equipment being:

BFD
600 watt amp
harrison labs FMOD 20 Hz HP filters if needed

Well your restraints are not too bad!

What impedance does your amplifier work best at? 4ohms?

There are lots of great woofer choices out there.

With the dual Dayton 12"HF's it would work well, however, if your amp only works at 4 ohm you better hope his subs are both 8 ohm or you will need another amplifier.

If they are, I would go with dual enclosures vented with the Dayton RSS315HF. Two enclosures External Dimensions of 21" W x 27.5" H x 23.5" D. Slot vent of 2" X 19.5" X 36". This keeps vent velocity below 14m/s simulating 500 watts rms. +/-3db from 22hz-82hz between 109.9db and 112.9db anechoic. This still allows quite a bit of space behind the sub for storage as well.

Just a thought though.


By the way I dig your DIY center channel! Nice!

 

[Guiria]

Well your restraints are not too bad!

What impedance does your amplifier work best at? 4ohms?

There are lots of great woofer choices out there.

With the dual Dayton 12"HF's it would work well, however, if your amp only works at 4 ohm you better hope his subs are both 8 ohm or you will need another amplifier.

If they are, I would go with dual enclosures vented with the Dayton RSS315HF. Two enclosures External Dimensions of 21" W x 27.5" H x 23.5" D. Slot vent of 2" X 19.5" X 36". This keeps vent velocity below 14m/s simulating 500 watts rms. +/-3db from 22hz-82hz between 109.9db and 112.9db anechoic. This still allows quite a bit of space behind the sub for storage as well.

Just a thought though.


By the way I dig your DIY center channel! Nice!

My amplifier is 600 watts bridged at 4 ohms. only 200 watts per channel in stereo at 4 ohms however so there isn't tons of juice for 2 subs. At only 200 watts per RSS315 I'm a little gun shy...

Also the deal with my wife is that the left cubby is for me, the right cubby is for the kids so I can't stick a subwoofer on the right side...lame.

By the way I dig your DIY center channel! Nice!

Thanks...unfortunately it is too big to squeeze between two wall joists so I am taking it apart and parting the drivers out on ebay and probably a couple of the crossover parts as well...I think I have a cap in that crossover that was 30 bucks! Hopefully I'll have enough doh once the dust settles to rebuild a smaller, mtm style center...there is always a compromise.

 

[annunaki]

My amplifier is 600 watts bridged at 4 ohms. only 200 watts per channel in stereo at 4 ohms however so there isn't tons of juice for 2 subs. At only 200 watts per RSS315 I'm a little gun shy...

Also the deal with my wife is that the left cubby is for me, the right cubby is for the kids so I can't stick a subwoofer on the right side...lame.



Thanks...unfortunately it is too big to squeeze between two wall joists so I am taking it apart and parting the drivers out on ebay and probably a couple of the crossover parts as well...I think I have a cap in that crossover that was 30 bucks! Hopefully I'll have enough doh once the dust settles to rebuild a smaller, mtm style center...there is always a compromise.

With some extra power, you could do a dual opposed sealed design with the RSS315HF. F3 would be 32hz with 600 watts rms at around 111db. This would require 5.0ft^3 net volume however. This would be about 21 W x 27 H x 20.5 D.

You will get some strong if not unpleasant interaction from the cubby being so small. Though, it is entirely possible that it may be of benefit in lowering the usable f3 point for the system, especially in a sealed application.

 

[Guiria]

I'm in the process of ebaying some things so we'll see if there are enough funds to get some more power in here...I'd like to.

 

[lsiberian]

These are my xmax RMS models of nearly all the well known high quality 12" subs ported

these are most of them sealed.

Not distortion measurements, but those are a lot more expensive to do.

Your next step up would probably be the Epic.

After that prices go up a lot and we start talking about the LMS 12" driver which would be amazing in any setup.

 

[Guiria]

That is very useful information thanks for posting it.

So it seems the RSS315 would be a lateral move from the Kappa I already own so that's out.

I've run into another issue as well...we've started using the cubbies for storing larger toys out of the main room and it's actually quite nice to have those spaces available.

Which means...

I am entertaining the idea of leaving the cubbies open and building smaller sealed boxes that will go on the bottom shelf.

Given this compromise I may be able to get two subwoofers for the lower shelf. One on each side of the TV.

If I left my bookshelf speakers on the lower shelf as well, then that means each box would only be 13x13x15 external dimensions. With only 200 watts driving each sub, I'm afraid dual subs would be highly underpowered.

Would I be better off using a single sub in those small dimensions so I can apply EQ and drive 600 watts to a single sub?

Or do i buy both subs now since buying a second down the road might be more difficult and hopefully score some better amplification down the road?

I'm hoping to end up with good 25 Hz output when all said and done...relatively speaking

Oh the decisions, not that I'm looking to be told what to do but writing this all out and hearing some opinions certainly helps.

I was looking at TLS subwoofer blogpost and the Dayton Titanic seems like it would fit into such a space and it can probably tolerate EQ boost a little better than an RS driver.

Off to school...I'm late

 

[Guiria]

Another thought is to put 2 AE IB15's in an IB configuration underneath the TV in the center of the room

Pros:
No floor space consumed
No cubby space consumed
IB setups are efficient and do not require tons of power like small sealed enclosures
Cool built in factor that if it sounds good would be really cool.

Cons:
Possibly incurable bass dips that I'd have to live with (this would also be a con of my cubby subwoofer placement, since that's the only place for it).
Possible outside volume problem - I'd have to check the volume outside my house since the eaves of my attic are vented to the outside.
If/When I move in 2 years these subs would have to go since I won't have room for them.

hmmm...

 

[Guiria]

To answer my own questions here are some plots I posted over at HT shack about some considered drivers. I will be able to increase my box size to about 1.5 cubic feet per sub. Sims were done in WinISD The following drivers were modeled.

2 CSS SDX10's 200 watts each
2 CSS Trio12's 200 watts each
2 Titanic 10's 200 watts each
2 Titanic 12's 200 watts each
1 Shiva X2 600 watts

 

[annunaki]

To answer my own questions here are some plots I posted over at HT shack about some considered drivers. I will be able to increase my box size to about 1.5 cubic feet per sub. Sims were done in WinISD The following drivers were modeled.

2 CSS SDX10's 200 watts each
2 CSS Trio12's 200 watts each
2 Titanic 10's 200 watts each
2 Titanic 12's 200 watts each
1 Shiva X2 600 watts

If you want to really see what response will be like you also need to be including rms power, low pass filtering, and simulating under SPL not maximum spl. You should also be checking xmax figures at or near tuning.

Many factors are at play and you should be accounting for all of them.

 

[Guiria]

If you want to really see what response will be like you also need to be including rms power, low pass filtering, and simulating under SPL not maximum spl. You should also be checking xmax figures at or near tuning.

Many factors are at play and you should be accounting for all of them.

I'm glad someone has something to say about this. I checked the xmax figures and all is good there...with 200 watts per driver none of these run out of xmax steam so that's good. I'll have to toy around with rms power and low pass filtering, I've never done that before. I realized I should have posted the SPL graph after I posted the Max SPL graph.

I use the program as a relative comparison between drivers and do not focus entirely on the actual decibel numbers. I figure they are close enough for me to make some pretty good assumptions about what to do.

 

[lsiberian]

What I did was put all the drivers in optimal boxes with optimal tunings with high pass filtering and xmax/rms limiting. If size is your limitation go for the sub that get's closest to that.