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Old 11th March 2007, 05:31 AM   #1
JinMTVT is offline JinMTVT  Canada
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Join Date: Jul 2004
Location: MTL
Talking Home Theater planning : ULTIMATE ?? !! need ur input!

Currently planning my new house...
I am in the design stage, currently working on the plans.

I have an approximate 20' by 20' room planned
for my home theater

It will be completly made out of concrete + foam
( the whole house will me made out of concrete from
ICF ( isolated concrete forms ) including floors/ceilings
and for the home theater room i am extending walls inside so it is bullet proof in terms of isolation to the rest of the house ( = more level possible without disturbing others!!! )

So now i am up to making decisions as to what kind of system will make up the sound, because if i need to take special steps ( concrete horns? ) i need to be able to include it all in the plans.


So what i want :

- Stereo setup ( i seriously dislike surrounds .. personal)
- VERY HIGH SPL ( even if it means a little trade off on quality )

i have almost no cost limitation since it will probably all be DIY stuff
i have almost no space limitation as i can design what i want/need in the house design

Will be driving from computer ( all media from networked computer ) to a DIY DAC = > DIY AMPS = DIY DRIVERS
( i luv you DIY guys

video is all planned, screen will take approx 115" of width from the front 20' wall

listening distance is 12' from the screen



What i have in mind now :

4 18"inchers on sealed boxes ..maybe 6 of em
either local Belisle Accoustic customs or Mc Cauley's 6174

alot of 5-6" for mids
and some good tweeters like the vifa D26NC55 ones..


I can put alot of treatments in the room
as my wife has nothing to do with this room
( ok i traded alot of other rooms for that one and the garage ..ahha )


What do you guys suggest ?

i was also lookin at concrete horns for the bass
any benefit ?
i wanna be able to make cloth move with bass

i was also told to check out the BassMax units?


Please take this thread seriously, i will base my REAL final design on all of your recommendations ..
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Old 11th March 2007, 05:42 AM   #2
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Join Date: Feb 2004
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Can't help you with the speakers, but your room dimensions present a problem. Having the length and width the same is a recipe for standing waves. This will have serious detrimental effects on bass in the room.
I suggest you do some reading up on acoustics before finalizing the dimensions. Particularily with regard to standing waves.
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www.dtsaudioelectronics.com
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Old 11th March 2007, 06:17 AM   #3
pjpoes is offline pjpoes  United States
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I think the decisions you make here will all depend on the whats most important to you. Before you decide this based on paper and forum posts, I do think you should try listening to some premade stuff first, to get an idea. I mean, if you make a sizable setup using a bunch of say Scan-Speak midbass drivers, the slit cones for instance, it will give you excellent dynamic performance, great sound quality, and very low distortion. Cost will of course be high, but some pro audio mids can be just as expensive. However, if you say you want a peak output in the 120-130 decible range, it will require quite a few of those midbass drivers for each enclosure, lets say 4. It will require a bit of power to drive it properly, and that will add to the expense. If you chose a highend midbass driver from a pro audio company such as Eminence, or better yet something like the Beyma's, you will gain a bit of efficiency. This will mean you can either use less of them to get the same output, or just as many and have potentially more output, all the while needing less amplifier power. However this will be at the extent of higher distortion and less accuracy. I personally can't deal with that, and would choose the high end home audio driver rather than the pro audio driver end of things.

As for your subwoofer, really, when it comes with excess in a home theater, I think you can never go too far. I am a bit of a bass head, but hey its fun. For the sake of your hearing though, you may want to consider bass shakers, to give you some of the tactile effects you want, without extreme output levels. None the less, IB could be a great option, using at least 4 woofers, but 8 or more is better, no. I also would consider using pro audio amplifiers and crossovers for the subwoofers, to ensure they are fed enough power. This has come up a few times, but Mach 5 audio has some great prices on some pretty high performing subs. The 18" sub is a great deal at less than 70 dollars I believe, so you could buy 8 of those for the price of the McAuley, and get plenty of nice deep, low distortion sub bass. I do not think that horns are a great idea for a Home Theater, not that they couldn't be, but to get a horn that can give you the low end extension you want with a theater requires a very large horn that is probably impractical for your purposes. When you consider that explosions in these movies contain significant content between 35hz and 15hz, or so, a horn that can handle that would be pretty extreme. Watts are cheap, so I wouldn't worry about the efficiency, and just stick with what measures best.
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Old 12th March 2007, 05:25 PM   #4
Graydon is offline Graydon  United States
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Join Date: Oct 2004
I am by no means an expert. I'm learning here just like many of the others around here. I am currently building a home theatre in my basement also and although I do not have unlimited funds, I am sinking a fair chunk of money into it. I also built the speaker boxes for the main left and right speakers into the concrete foundation. I am going to try to fit some exponential horns into the system but right now I have a couple Eminence 18s mounted in the left cabinet and it is all sealed up. It will play sound down to under 15Hz. It makes serious sound at 23 Hz and above. I have lots of work to do yet with damping and the baffle needs to be braced. At low frequencies, it vibrates as much as the woofer cones. :-) You can read more here...

http://gdsamps.wordpress.com
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Old 13th March 2007, 04:07 AM   #5
JinMTVT is offline JinMTVT  Canada
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Join Date: Jul 2004
Location: MTL
audiopro :
thanks for the advices, but i am already aware of all those constraints ..sizes i gave are just and approximate
and the room will not have straight walls ...

pjpoes :

i would normally not compromise quality over anything
but for home theather, that will probably never see any music at all ..i will be making some compromises toward sound level and low freq response!

keeping that in mind, i do not believe that scan-speak slits or other expensive hi-fi drivers would give anything to the overall feeling of this system

Should i be thinking about arrays ?
i mean , lower distortion, good spl possibilities
i don't care that much about combs for movies,
and other tradeoffs aren't that bad if you pop the volume up ?
the room will also receive alot of absorption since all it's walls will be covered by 2-3" thick foam on the concrete

I really like Graydon's style to encompass the sub enclosure into the rooms concrete building
what are the benefits of that type of enclosure?
It would cost me probably only a few hundreds more to have the walls extend toward to make such enclosures on each side ...could nicely fit 4 18"inches on each side


BassShakers are also consired as pjpoes proposed ,
anyone has experience with some units?
what are the requirements? possible settings?

thanks for the help guys!
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Old 13th March 2007, 01:33 PM   #6
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Join Date: Dec 2004
Location: Melbourne, OZ
Default Re: Home Theater planning : ULTIMATE ?? !! need ur input!

Hi JinMTVT,

You're very lucky in being able to build your dream HT from the ground up! This is not an option for most of us so please spend as much time as it takes to investigate your options before committing.


Quote:
Originally posted by JinMTVT
Currently planning my new house...
I am in the design stage, currently working on the plans.

So what i want :
- Stereo setup ( i seriously dislike surrounds .. personal)
- VERY HIGH SPL ( even if it means a little trade off on quality )

What i have in mind now :

4 18"inchers on sealed boxes ..maybe 6 of em
either local Belisle Accoustic customs or Mc Cauley's 6174

alot of 5-6" for mids
and some good tweeters like the vifa D26NC55 ones..

I can put alot of treatments in the room
as my wife has nothing to do with this room
( ok i traded alot of other rooms for that one and the garage ..ahha )

Please take this thread seriously, i will base my REAL final design on all of your recommendations ..
So you've decided on Stereo only - fine, that's your choice. Do you see yourself ever selling the house in the future? If so it may be worth making *some* provision for surround, so you can sell the home theatre as another feature. All I'm saying is consider putting in ducting and cavities so the surround and centre speakers + wiring could be fitted by the next owner. Nothing to stop you fitting blanking panels over the holes for now.

Here are some thoughts and suggestions - I'd love to build something similar in the future - one day.. <sigh>

1) Build simple 'alcoves' or cavities into the wall to house the speakers, then build your speakers with matching baffles to fit flush with the rest of the wall. This allows you to change your mind in a few years time, maybe go from horns to regular speakers or vise-versa. Think of the largest box you would ever want to accomodate and allow a few inches each side to allow the boxes to be removed if needed. Will the speaker be behind the screen or either side of it?

2) Very high SPL = horns! Consider a hybrid cone / horn option to keep your boxes a reasonable size. All horn-loaded is a nice thought but may not be practical.

As you've stated you can use 18" subs, how about:

up to 100 Hz = multiple 18" subs in coffin-sized sealed enclosures (estimate 92-96 dB/watt)
100Hz - 800Hz = single horn loaded 10" or 12" (estimate 104-108dB/watt) horn mouth up to 24-30" square, needs similar depth.
800Hz - 16KHz+ = 1" or 1.5" compression driver on waveguide (estimate 108-110 dB/watt)
16KHz up = optional supertweeter, do you think you'd need one? How's your hearing that high? Your decision :-)

With the very high sensitivity horns offer you're going to need less than 1/10th of the power you'd need with regular cone mids + tweet. Every 3dB increase in sensitivity = 1/2 the power required for same SPL, so to reach 120dB @ 1 metre, you'd need:

Subs: 300 watts (93dB sensitivity)
Midbass: 30 watts (105dB sensitivity)
Treble: 15 watts (108dB sensitivity)

Active crossover - use your PC as it's already the music source.

There are MANY good choices for the 10"/12" and compression driver - that's an entirely new discussion
Take some time to look at some of the horn projects around on the web, search for Earl Geddes' designs, check out the JBL Lansing forum, etc etc.

3) Room treatment is as important as your choice of speakers. Take the time to research other high-end installations or even consider paying an acoustic consultant for a recommendation. Considering the total build cost, a few hours discussing the room acoustics with a professional would be money well spent in my opinion. Apart from room treatment / dimensions, this includes things like air-con, ducting for the projector, etc.

cheers,

Len.
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Old 14th March 2007, 04:37 AM   #7
JinMTVT is offline JinMTVT  Canada
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Join Date: Jul 2004
Location: MTL
Default Re: Re: Home Theater planning : ULTIMATE ?? !! need ur input!

Quote:
Originally posted by len_scanlan

You're very lucky in being able to build your dream HT from the ground up! This is not an option for most of us so please spend as much time as it takes to investigate your options before committing.






So you've decided on Stereo only - fine, that's your choice. Do you see yourself ever selling the house in the future? If so it may be worth making *some* provision for surround, so you can sell the home theatre as another feature. All I'm saying is consider putting in ducting and cavities so the surround and centre speakers + wiring could be fitted by the next owner. Nothing to stop you fitting blanking panels over the holes for now.

Here are some thoughts and suggestions - I'd love to build something similar in the future - one day.. <sigh>

1) Build simple 'alcoves' or cavities into the wall to house the speakers, then build your speakers with matching baffles to fit flush with the rest of the wall. This allows you to change your mind in a few years time, maybe go from horns to regular speakers or vise-versa. Think of the largest box you would ever want to accomodate and allow a few inches each side to allow the boxes to be removed if needed. Will the speaker be behind the screen or either side of it?

2) Very high SPL = horns! Consider a hybrid cone / horn option to keep your boxes a reasonable size. All horn-loaded is a nice thought but may not be practical.

As you've stated you can use 18" subs, how about:

up to 100 Hz = multiple 18" subs in coffin-sized sealed enclosures (estimate 92-96 dB/watt)
100Hz - 800Hz = single horn loaded 10" or 12" (estimate 104-108dB/watt) horn mouth up to 24-30" square, needs similar depth.
800Hz - 16KHz+ = 1" or 1.5" compression driver on waveguide (estimate 108-110 dB/watt)
16KHz up = optional supertweeter, do you think you'd need one? How's your hearing that high? Your decision :-)

With the very high sensitivity horns offer you're going to need less than 1/10th of the power you'd need with regular cone mids + tweet. Every 3dB increase in sensitivity = 1/2 the power required for same SPL, so to reach 120dB @ 1 metre, you'd need:

Subs: 300 watts (93dB sensitivity)
Midbass: 30 watts (105dB sensitivity)
Treble: 15 watts (108dB sensitivity)

Active crossover - use your PC as it's already the music source.

There are MANY good choices for the 10"/12" and compression driver - that's an entirely new discussion
Take some time to look at some of the horn projects around on the web, search for Earl Geddes' designs, check out the JBL Lansing forum, etc etc.

3) Room treatment is as important as your choice of speakers. Take the time to research other high-end installations or even consider paying an acoustic consultant for a recommendation. Considering the total build cost, a few hours discussing the room acoustics with a professional would be money well spent in my opinion. Apart from room treatment / dimensions, this includes things like air-con, ducting for the projector, etc.

cheers,

Len. [/B]

Originally posted by len_scanlan You're very lucky in being able to build your dream HT from the ground up! This is not an option for most of us so please spend as much time as it takes to investigate your options before committing.
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Old 14th March 2007, 04:45 AM   #8
dangus is offline dangus  Canada
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Join Date: May 2004
Location: Vancouver Island
I'd think about using a #$#@-load of smaller subs, like the Adire Tempest or whatever 12" to 15" offers good value and high-excursion. IIRC the 6174 doesn't go really low unless you use a ported cabinet.

Using many drivers will a) sound more impressive when you describe your system, and b) let you spread them all around the room to get more uniform bass. Corners, mid wall, midway up the wall, maybe 4 columns each with 4 drivers. 4 drivers will be 4x as efficient as one, so you'll approach horn-like efficiency, but with hopefully a smoother and deeper response and easier construction. This may also allow you to get away with using some EQ to get down near the "brown note" frequency range, which will be useful when watching "Black Hawk Down".

"Unity" horns would be nice for the main speakers.
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Old 14th March 2007, 04:48 AM   #9
JinMTVT is offline JinMTVT  Canada
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Join Date: Jul 2004
Location: MTL
Default Re: Re: Home Theater planning : ULTIMATE ?? !! need ur input!

Quote:
Originally posted by len_scanlan


You're very lucky in being able to build your dream HT from the ground up! This is not an option for most of us so please spend as much time as it takes to investigate your options before committing.



Well that is what i will be doing! wise advise
I have a few months before starting to build the house
and probably 1-2 year before the actual home theater

......All I'm saying is consider putting in ducting and cavities so the surround and centre speakers + wiring could be fitted by the next owner. Nothing to stop you fitting blanking panels over the holes for now.

I am planning to live in this house for the next 20years+
so there is no way that i am compromising on anything other than what i need/want

I did not ever reserached Horns construction or benefits at all, since i never actually thought about it

the reason why i wanted to bring HORNS in the discussion is for bass and high spl
but from what i can deduct, 100hz and lower optimized horns would be way too big for a regular house right?

what are the actualy benefits of horns in the mids?
downfalls for the same region ?

I actually wanted to use a 2 way + sub for lower end reinforcement ..
there is no point in trying to get the best possible quality out of a home theater that will require lots of excursion and high spls for me ....
would just cost way too much

I will need to design at least 4 other sound systems, in wich 2 of them will be base on sound quality first
( music only systems )
So i want to be able to have time to do them all in my life time ( already got 2 buisness ...no time! )


So what about horns for 100-800hz ?
what would it bring?
and what kind of design for horns?
and what size would it use?
how many drivers?

thanks alot again
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Old 16th March 2007, 05:39 PM   #10
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First off congratulations on being able to build a dream home theater!
Second, you are the first person I have ever heard say that surround sound is bad for movies. This begs the question why, and also have you ever heard a good surround system? len_scanlan has a good point, don't limit yourself now when there are zero negative effects of including surround capabilities-its just wiring!

IMO, stay away from horns and don't focus too much on excessive spl.
Why not horns, well your room is not that big, your planning on at least 4 18's, and you will most likely have an equalizer. With enough cone area, amplification and eq you can get whatever f3 you want. Horns are efficient yes, but they are huge in your frequency of interest, also they are expensive with all of the material you will need and they require some knowledge and experience to design and build.

Excessive spl, this should be obvious, 120-130dB will damage your ears quickly. You don't need it, and the good news is that it is easy to get the 120 dB range with almost any group of 4 18's.

Enough of what I think you should stay away from. I am a fan of IB/dipole woofers so naturally I would recommend that arrangement. Just for reference I am currently using one Dayton 15" IB in a 21" long u-frame dipole, and the f3 is ~28hz (no eq) with proper room placement and the room is a little smaller than yours. Eventually I will have two of these in a 4-way dipole (one sub per cab.) and it is plays louder than I ever need it to. If they were mounted on an IB then they would extend a lot lower.

I would say as others have mentioned, that the room treatment is the most important thing for you to focus on. Definitely round or bevel the corners of the room, this will create some IB sized chambers for your subs and will do wonders for the sound quality. Also consider one to two foot thick panels of fiberglass insulation on the side walls to counteract the square dimensions. The insulation needs to be thick to affect the bass, and of course it will deaden the upper frequencies which will most likely hurt imaging. Something I want to try with thick fiberglass on the walls is some highly reflective panels located at the first reflection points, this should restore the imaging and "liven" up the room a little. If I were you I would spend most of my time researching room treatments/acoustics.
The roof, front wall, back wall and the floor all provide strong reflections which affect sound quality.

Good luck
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