8 Subwoofers on ceiling !!

[elangoas]

Hi All,

Had a thought, wanted to check on its feasibility..

This is for my brother.. He likes a bass at higher levels.. I had planned few things for his room in near future.. His room is abt 22 (L) x 11 (W) x 10 (H).. At present he has 7.2.4 set-up.. He has 2 x 12 inch DIY sealed subwoofer on ceiling.. Planned for 4 of them ceiling, but this idea came up.. Wanted to check..

Having already mounted 2 subs on ceiling in my room, i was thinking on similar lines for him, to mount all 8 subs on ceiling, drivers firing into the room..

Budget - Max of 1 Lac (+/-) 20%..
Power amplifier - Sonodyne (8 channel amplifier, capable of 90 watts continuous power at 4 ohms)..
Drivers - Can procure 8 x 12 inch drivers locally (IWAI)..
Location of subs - Ceiling..
Mounting location - Pair of drivers just outside 1/4 room length & 1/4th room width points, along the room length.. Below is an image of his living room, speaker placements in the room & planned subwoofer locations.. The reason for considering pair of drivers at location is to get the drivers closer to the 1/4th room width & 1/4th room length points..

His room is symmetrical, but there are some large openings, but have planned to close the large opening part in the room..

He doesn't have Mini DSP yet, but would get it sooner for him..

Procuring, building sealed enclosure and mounting them on ceiling, we can fairly manage.. I would like to try, but wanted to check if it is a good choice?.. What would be the challenges?..

 

[Love4sound]

Well having placed two subs in ceiling you must know all the challenges. Just multiply the challenges you faced into 4 times . And why 8 subs? 4 should be enough. Why go through the hustle ?

 

[elangoas]

Well having placed two subs in ceiling you must know all the challenges. Just multiply the challenges you faced into 4 times .

Ha ha.. Effort is the same.. First time i did it, it was tough.. But now been thru that, fairly can plan things..

And why 8 subs? 4 should be enough.

More is good IMO, lesser work for each sub, more even bass distribution in the room, capability of much higher SPL.. He just like to push subs volume..

Why go through the hustle ?

Agreed.. But should be good, if executed correctly..

 

[Love4sound]

Ha ha.. Effort is the same.. First time i did it, it was tough.. But now been thru that, fairly can plan things..



More is good IMO, lesser work for each sub, more even bass distribution in the room, capability of much higher SPL.. He just like to push subs volume..



Agreed.. But should be good, if executed correctly..

Yeah 4 is more only hahaha. Anyways very interesting build up.

 

[VRavichandar]

Keep going with new ideas - the zest is appreciable, I do wonder a little bit about the ratio of time you spend setting things up vs time you listen to your set up!

 

[elangoas]

Keep going with new ideas - the zest is appreciable, I do wonder a little bit about the ratio of time you spend setting things up vs time you listen to your set up!

Ha ha..Thanks.. Both, equally ..

 

[raghupb]

With a custom build how does one control crossover and level for each sub?
Cheers,
Raghu

 

[elangoas]

With a custom build how does one control crossover and level for each sub?

When we use with AVR, external crossover isn't required, as we use the AVR's internal crossover of 80/90/100Hz and that should do..

For levels, most external amps, would have gain control (or) volume knob for each channel.. So that will help for levels..

Incase the external power amps don't have gain control, we can use the speaker/subwoofer level (-12 to +12) in the AVR settings menu and adjust the levels for each (or) summed levels for each sub out..

 

[raghupb]

Ah.. Ok. Got it.
So these will mainly be used with a distribution amp using low level signal from AVR
Cheers,
Raghu

 

[elangoas]

Ah.. Ok. Got it. So these will mainly be used with a distribution amp using low level signal from AVR

Yes, sub pre-out..

 

[madhanmss]

Ji, Do you have space to actually live in the house? seeing the equipment going in i wonder. And your wife does not say anything?

 

[elangoas]

Ji, Do you have space to actually live in the house? seeing the equipment going in i wonder. And your wife does not say anything?

Not in my tiny living room.. This is for my younger brother.. Having multiple subs on the floor in a living room is just not possible.. 7ft above the living room no one at home cares what you do.. Hence targeting space..

No luxury of dedicated space for HT.. But, just trying to reuse the unused space in living room for better..

 

[Dr.Lakshay]

I myself being a bit of a bass head would be content with 4 subwoofer going by the room size. I feel 8 subwoofers will be an overkill until and unless you want to setup a dj for a farmhouse or something.

Even I am going to have to shift my subwoofer to ceiling (taking ideas from you) because of renovation and furniture taking precedence over subwoofer. And am thinking of upgrading from one to two subwoofers.

 

[elangoas]

I myself being a bit of a bass head would be content with 4 subwoofer going by the room size. I feel 8 subwoofers will be an overkill until and unless you want to setup a dj for a farmhouse or something.

I too thought of 4 subs initially for his room size, but for few reasons i thought of 8 subs..

- When you put a single sub on the floor, there is a good amount of gain as the sub is close to surface / boundary.. The moment you raise it off the floor and keep it away from boundary, it looses it gain.. So to add more SPL, you need more drivers.. Addition of each subs, gives a good capability of SPL.. And that too have planned for sealed..
- More subs, and at ideal room locations will make the response better at any place in the room..
- More the subs you have, the power demand for each sub goes down to a greater extent.. 60 watts of continuous power for each of 8 subs would be great than 120watts of power for each of the 4 subs..
- Cost saving between 4 subs & 8 subs (DIY passive) is not substantial (In my brothers case).. Hence the idea of 8 subwoofers..

Even I am going to have to shift my subwoofer to ceiling (taking ideas from you) because of renovation and furniture taking precedence over subwoofer. And am thinking of upgrading from one to two subwoofers.

Great.. Two is good.. Position it right on ceiling, so you don't have to re-position it again.. Please share your progress / updates, when you begin work.. Good luck..

 

[madhanmss]

Not in my tiny living room.. This is for my younger brother.. Having multiple subs on the floor in a living room is just not possible.. 7ft above the living room no one at home cares what you do.. Hence targeting space..

No luxury of dedicated space for HT.. But, just trying to reuse the unused space in living room for better..

I saw the design. squeezing the atmos speakers in between subs will not have any impact? and they are down firing or positioned to the listener?

 

[elangoas]

I saw the design. squeezing the atmos speakers in between subs will not have any impact? and they are down firing or positioned to the listener?

The pic was approximation of where i planned to mount them on ceiling.. The plan is to erect a wooden frame between the 11ft high walls in the room to hold the subs firmly.. They are not in-ceiling speaker.. Specifically didn't opt for it as the need to tilt (angle) may be too much towards his listening position.. So mounted bookshelf speaker and are angled towards his listening position..

After mounting subs inside the wooden enclosure in-between high walls, the heights will be re-positioned and mounted on the wooden enclosure firmly..

 

[sbg]

Hi All,

Had a thought, wanted to check on its feasibility..

This is for my brother.. He likes a bass at higher levels.. I had planned few things for his room in near future.. His room is abt 22 (L) x 11 (W) x 10 (H).. At present he has 7.2.4 set-up.. He has 2 x 12 inch DIY sealed subwoofer on ceiling.. Planned for 4 of them ceiling, but this idea came up.. Wanted to check..

Having already mounted 2 subs on ceiling in my room, i was thinking on similar lines for him, to mount all 8 subs on ceiling, drivers firing into the room..

Budget - Max of 1 Lac (+/-) 20%..
Power amplifier - Sonodyne (8 channel amplifier, capable of 90 watts continuous power at 4 ohms)..
Drivers - Can procure 8 x 12 inch drivers locally (IWAI)..
Location of subs - Ceiling..
Mounting location - Pair of drivers just outside 1/4 room length & 1/4th room width points, along the room length.. Below is an image of his living room, speaker placements in the room & planned subwoofer locations.. The reason for considering pair of drivers at location is to get the drivers closer to the 1/4th room width & 1/4th room length points..

His room is symmetrical, but there are some large openings, but have planned to close the large opening part in the room..

He doesn't have Mini DSP yet, but would get it sooner for him..

Procuring, building sealed enclosure and mounting them on ceiling, we can fairly manage.. I would like to try, but wanted to check if it is a good choice?.. What would be the challenges?..

Will this setup need some phase corrections, depending on "each-other" subs positions - i.e each sub in relations to the other 7?
I had difficultly with 3 sub ( compounded by the fact all the 3 are different makes). so , I use to end up tuning each time or use only one.

 

[kissenchand]

Many coherent sources lead to interference phenomenon of waves. It may seriously affect the resultant sound field. May be very loud in some spots and feeble in some others.

 

[elangoas]

Will this setup need some phase corrections, depending on "each-other" subs positions - i.e each sub in relations to the other 7?

So far my experience has been with only Audyssey automatic room correction.. Am technically novice w.r.t tweaking subwoofer manually.. Moreover his AVR is Onkyo with Accu EQ Advanced room calibration, never manually edited that too..

But have planned to get miniDSP to adjust the time difference.. I know it is going to be technically challenging, but not aware of how complex or easy it is with miniDSP in chain..

I had difficultly with 3 sub ( compounded by the fact all the 3 are different makes). so , I use to end up tuning each time or use only one.

This one will be all identical drivers and identical enclosures, not to give for error there.. So i guess all lies in rightfully configuring them.. Hope to get it done the hard way..

Many coherent sources lead to interference phenomenon of waves. It may seriously affect the resultant sound field. May be very loud in some spots and feeble in some others.

Thanks you @sbg and @kissenchand for your technical inputs, this is what i have been looking for to understand & evaluate the complexity of this to do task..

On AVS forum, many have attempted with more than 4 subs, some with even 12 subs in a room.. I know i wouldn't be able to do it correct, first time.. Just hoping to get it right by trial and error..

The easiest i thought of was to have two horizontal rows of subs.. 4 subs in each row.. His planned listening position would be among the 8 subs.. $ subs ahead of him and 4 subs behind him.. From my limited experience with multiple subs, all i know is that fairly freq response would be good in-between the subs.. It will be a progressive effort..

 

[RajithKumar]

Elangoji ,unless adding a minidsp kind of product ,how you are going to match the time and phase alignments for 8 subs...