Ultimate home theater rooooom ..NEED UR HELP NOW! :)

Ok, If you have the oportunity to start from scratch, I would suggest that you mount all the boxes flat into the wall, use a dampening material on that wall so that early reflections are minimised.

Mounting the speaker flat in the wall is the basis of THX in the cinemas, It allows the speaker to work as a piston and with the air is controlled, no need for baffle step compensation and allows a far more acurite wave to be created, than possible from a regular box.

A large sealed inclosure will sound better than bass reflex in this mounting. The flat baffle wall will boost the lowest frequencies. So bass reflex designs would sound very boomy and usually need to be cut back by eq.

As you are constructing your options for breaking up the sound on the rest of the walls is up to you, curtains like in cinemas, 3d patterns with the brickwork would all help, or some movable fiberglass baffles on frames can do the job very well.

I would also suggest 15"duel concentric speakers like tannoy or altec (the very best that I have heard) others make cheaper options such as p.audio and eminence ect. The single point sourse does sound far more natural than conventional split designs from my experience.

As for the suround channel, the more speakers the better, 8 ideally or 4 would be good, bi polar designs should be considered, frequency range is 100hz to 7,000. 4 inch full range speakers can cover this range very very well. Speakers start 2/3 down the side walls and behind on the back walls for best seperation.

Ive designed and custom built several large cinema speaker systems over the years and this is what I would do for my own pleasure in your place.

Good luck on whatever style of system you choose, and on the rest of the house.

Surround channels in DD/DTS and newer are all descrete and full range, they were only bandwidth limited in Prologic 😉

um no there not, What do you think 5.1 means? Six channels or 5 channels? or 5 channels with one split @ 100 hz to equal 6, Now if thats the Left surround thats split, do you think the sound mixer is going to put deep bass on the right surround only ? or put the deep bass for both the surround channel into LFE channel which has a stack of 18" speakers on stage mounted into a Baffle Wall?

Cinemas and Mixing suites set up to either DOLBY or THX standards use an academy curve on the surround chanel. ie 3 db roll off from 2K to create a more defused and less directional effect with the multiple speakers.

So if you want to have a surround effect like the way the movie was mixed and was intended to sound like, um my suggestion was fine and a bit cheaper than what a salesman would try to sell you.

Calm down mate 🙂

What you're saying may be true for cinema installations, but home theatre systems are different.

Taken straight from the Dolby Website...
"* The sound information contained in each of the six available channels is distinct and independent. These six channels are described as a "5.1-channel" system, because there are five full-bandwidth channels with 3 Hz to 20 kHz frequency range for Front Left and Right, Center, and Surround, plus one "Low Frequency Effects" (LFE) subwoofer channel devoted to frequencies from 3 to 120 Hz"

If you done believe me (or Dolby 😀 ) try setting your system up so it doesn't redirect bass from the 5 main channels to the sub and play Saving Private Ryan at reference level. Then watch as your 4 inch full range surrounds fire their cones across the room

Personally, I use a LEDE type of setup, with the surround speakers at the live end.

Quite a few people prefer bi-polar surround speakers, myself included. In general the surrounds in movies are used for ambience most of the time, so a difuse sound is what you're mostly after. You still need some ability to pin point the surrounds though for effects you are supposed to be able to locate, so the design is a compromise. I'm going to have a go at some M&K'alike tripoles in the future, as they look to be a good mix of difuse and directional radiation.

Usually the surround speakers are best setup high on the side walls slightly behind you, Dolby suggests between 90 and 110 degrees to the screen. In a 7.1 setup the surrounds stay where they are and the two surround back speakers are placed close togeather and directly behind you, similar height to the side surrounds.

Dolby Digital and DTS are encoding standards, THX is a reproduction system standard, basically a set of specifications a setup must comply with for THX certification. The ideal setup would be 7 full range speakers with dipole radiation for the surrounds, each capable of producing 100db peaks at the listening position and a subwoofer able to produce 115db+. The advantage of having all speakers full range is extra cone area and therefore potentially low distortion bass, and hopefully no sub localisation. The disadvantages are all speakers would require EQ to counter room modes and very large main speakers.

THX specifies main/surround speakers with a 12db/octave rolloff at 80Hz, handing everything below that to the sub. The surround processor/amp adds a 12db/octave, 80Hz rolloff to the main speakers and a 24db/octave linkwitz riley lowpass to the sub, netting a 24db/octave crossover . This is a far more sensible idea as getting you main speakers down to 80Hz in a sealed box and able to output 100db is dead easy and would result in much more domestically acceptable speakers. Usually a single 6-7" woofer per speaker is sufficient, which means you can put more of the budget into the sub/s

To playback at reference level is very demanding for the sub, usually a pair/quad of 15's is required depending on your room and amplifier size. The two things to remember are... 1:- More cone area is better and 2:- You need some form of room EQ.

The front speakers are pretty free choice, some people prefering TM layouts, some prefering MTM's. Again it's one of those things you usually have to try and then decide what you like best. The most important things to remember about the front three speakers are that they are all identical and all placed at the same height. I can't help but laugh when you see pictures of peoples systems with the centre speaker either 10ft above the left and right on top of their projection screen or on the floor below 😀

I have a fairly small room and not many seats so I don't bother with a centre speaker, just the left and right. Unless you have people sitting pretty far off axis a centre isn't really that nessesary.

Run, do not walk, to a nearby "home theatre" specialist. It might cost you a little but IF you mess anything up it'll cost you a heck of a lot more to correct it later!
You're going to need equipment anyway so let them help you through the entire process. Win, win.

Insulated concrete forms?

Are we talking basement here?

Then I hope this means an hydronic heating system with piping in both the floor below and the floor above. Good for you if that's your plan. You'll get the most efficient heating system and the ability to isolate most of the HT sound from the rest of the house.

Aside from having some concrete forms onsite when the flat work is poured (for sub boxes), I can imagine any other built in design features would be very costly and just be confining for future changes.

"Flat mounted speakers" make sense in many ways, especially to go with flat displays, but this can be done easily utilizing typical stud-wall construction against its interior. Are you planning this anyway? If that's the case and you're going to have plasterboard sidewalls, you might consider framing them in four foot sections, and installing them sawtooth style. If you built that to a soffit you'd have a raceway for future wiring and a unique placement for spot lighting.

One idea I would consider, is to have a utility room behind your entertainment wall to provide access to the component wires, with good lighting.

I would go along with FullThrottleRic: " ... Calm down mate ... six channels are described as a "5.1-channel" system ... "

Having previewed THX, Db 5.1, Db 7.1, et al, at the trade shows past and recent, the only real differences is the ultimate placement and number of speakers. Personally, I would stick with the 5.1 scenario = L&R mains, L&R surrounds, sub woofer(s) and maybe a pair of L&R rears ... but be ready to disable those rear speakers, especially if that's where the snack bar is going. 😱

Construction Notes:

* Put in EMT steel piping (or plastic electrical piping) from the ceiling down (commonly called "stub ups") with "4 square" boxes at the bottom, about knee level. (Don't let the electrician talk you into "counter top height" [41" to 44"] or "floor level" [10" to 18"] ... these outlet boxes should be knee height [20" to 28"] from the surface of the finished floor. Limit the number of bends in the pipes and don't try to interconnect the piping into a single main pull box ... times change, equipment changes and so will the topogrphy of your listening room.
You should consider at least two 3/4" ID pipes coming down behind your amp cabinet and an additional one or two for the big screen display or at least three pipes down the display / amp cab. wall if all playback / output equipment is there. (One pipe for a seperate power feed, one pipe for outbound cables to those surround speakers and one pipe data incoming. Your data pipe should be ready for TV cable, roof top radio antenna, ethernet cable and possibly more = 3/4" ID minimum. These pipes can be burried in the wall behind that foam but the data and speaker pipes should just be "stubbed up" into the ceiling crawl space ... if you don't have any crawl space above = = you may have to build wooden raceways or really big pipes to feed it across the room to your equipment. The data pipe might run clear to the garage area (or where ever your service entry is located), but in that case it should be 1" ID or even bigger as the technollogies change, you may need to add fiber or additional ethernet cables or whatever.

* Don't even consider any wireless audio and/or video scenarios. The neighborhood hackers will crack into your wireless Internet feeds, the cruising cop cars will blank out your signals, the airport will complain, and WiFi or SuperWiFi or WiMAX or whatever the latest flavor is is not nearily fast enough for quality AM radio, let alone 24 bit / 192K Db 5.1 audio plus HDTV. Hardwire to the Internet is the only way to go = fiber is better but not fully debugged yet.

* Don't forget about "ordinary" FM radio. You will want an antenna feed from the roof, sooner than later. FM radio is going digital quickly = multichannel 24bit / 96K bandwidth just fits into the allowed FM radio broadcast bandwidth allotment (100K x 2) and it sound great thus the feed pipe to the roof for an antenna. ... 😀

(If you go with steel pipe, don't ground it to any of your audio or video equipment, just to the water pipes or not at all ... local Canadian building codes require grounding all metal pipes ... local golden ear audio codes require that you reduce or eliminate possible ground loops = no grounding to speaker runs, signal runs, data runs at either end, period.)

Originally posted by JinMTVT How one can achieve same height front and central speakers with the screen ? i don't have an IMAX screen to use drivers behind 😛

Click to expand...

Easy 😀




You have 9' of vertical space to play with, assuming you build floorstanding main speakers about 3' high you will have say 5' for screen height. That would give you a screen width just under 9'.

jbl cinema

Ok at the bottom of the JBL page is additional links, Thats what is installed in the cinemas and mixing suites

P.Audio 15 " duel concentric

efficiency is close to 100db at 1 watt / 1 metre, materials are the same as films are mixed on, ie titanium large format compression drivers. It creates a clean point sourse and has minimal time alignment issues. It is affordable!

the best sounding choice (and most expensive)
Altec


Sub bass, well I would go for an 18" in a large sealed box mounted in the wall.

Surrounds as I said before I would personally go for the more the better approach. By concentrating on using speakers that have a flat response between 100 hz and 7k, and a natural sounding midrange for an optimum effect.
Bass not being directional means that using the surround channels as a satilite stlye of channel is one difference I can not actually notice. The surrounds in my home are vifa full range 3 inch drivers in one litre boxs and did infact survive Saving Private Ryan.



vifa second driver down

5.1/ 6.1 . Dolby EX is a prologic rear channel created from the left and right surround channels. Most films are still mixed for 5.1. The noticable difference is that sound panpotted to fly over you in 5.1 would actually fly behind you if decoded in 6.1.

Um now, films are not remixed for home release, so the cinema mix is what you get, so the limitations of the earlier late 80's cinema format are transfered to the later DVD format.

Now This is what I would do if I was building my own home cinema from scratch, its a unique opertunity to create someting exceptional. Personally I would use a sound screen exactly as found in a cinema. They have lots of little holes in them to let the sound through. Here is a shot of one in my garage.

Here is a cinema that I designed, costum built and installed the speakers for, it was opened in 1995. The acoustics are very good because of the 3d plaster effects break up the sound. Backstage is damped with black tissuefaced fiberglass that is 3.2 kilograms per sq meter. Speaker boxes are 2x15 inch and a 2" horn each mounted flush it own custom wall. 1 x 18 inch sub. seating 350.

This 750 seat cinema for many years featured lots of 4 inch full range speakers for its surround channel, that I concealed behind the extensive plaster work around the auditorium, in areas less than 10cm thick. Dispite an auditorium being over 110 ft wide, these speakers did survive running TITANIC in 70MM. Backstage is ALTEC a4s x 5, modern JBL 2" horns, and a 4 stack of EV 18 " subs operating flat from 25 hz.

Cameron, I dont mean to be rude but we arn't feeding our systems with the origonal film stock, neither is the guy building a 750 seat cinema

Soundtracks for DVD's are remixed from the origonal to better suit home playback systems, usually using some varient of M&K System, Skywalker sound use active versions of the system linked in their smaller mixing rooms.

JinMTVT: In a perfect world all three fronts would be exactly the same, it's obvious you should use the same left and right speakers in stereo, the same applies to the centre too 😉
Also in a perfect world we would all have a perforated screen and have the front array behind it, failing that the layout I sketched above is a good compromise. You have plenty of room to play with though, how about adding another wall a couple of feet infront of the front wall with the screen in and building the front speakers into it behind a perforated screen? You could have racks either side of the screen housing your electronics and subs either side of the screen at floor level, that way everything except the projector and surrounds is togeather and easier to wire up/keep tidy 🙂