Axiom Home Page Forums General Discussion Home Theater Speakers for 30 foot x 40 foot screening room

"Using big cinema horns is certainly an option. That's what's used exclusively in evensmall commercial cinemas, because you can get very high SPLs, great dynamics, and you can do it without having to use monster amplifiers. BUT, you have to use careful equalization or the horns will take your ears off. Big EQ'd horn systems can sound really good if the person setting it up knows anything about good sound quality. And that's a big IF."

Well, I don't even know how to set up "proper equalization," so that, as they say, appears to be that. Also, whereas I should probably know what "SPLs" are, in fact I do not. ;-))

"Most in-wall speakers that are flush to the wall are quite inferior to well designed tower speakers if you're after neutral, uncolored sound. And they are not efficient (sensitive) so you have to use really huge amplifiers."

Except for th Axiom variety, right? Still, you cannot direct these up-down left-right with something like a FULL METRAL BRACKET, right? Well, without listening to speakers first and deciding on which types to get later, there may not be a purchase answer/solution here at all.

"I don't understand your resistance to using floorstanding main speakers up front."

Well, to be honest with you, I have never seen any speakers sitting, laying, or standing on a theater/screening room floor, except for in smaller home theaters. I believe in a cinema setting, even the subs are elevated. But there is one posibility for placement that I just of thought of, Alan, and wanted to run it by you!

And that would be to have the screen a short distance mounted, and then the front edges of the (curved) screen would be extended vertically from side to side and top to bottom by speaker cloth fabric. This way, there could be "floorstanding" speakers mounted on a podium, but this would not be visible from the room, hidden behind the speaker cloth "wall." Similarly, the center speker(s) would alos be hidden from sight, mounted to the wall just behind this black speaker fabric that would stretch basically from the four edges of the screen to the four edges of the front wall of the room.

Do you follow me here, or should I try to give it another jab?

"I would go with three 80s for the front, and dual EP500 or EP600 for subs. If you forsee vvolume levels of 90db and above, I would be checking into seperate amps for the front 80s. When I started pushing five M80s at high levels, I learned I could put multi channel amps into heat protection within 12-18 minutes.

As for the M80s, they are rated at 400 watts each at 4ohms, so they are happy and only sound better with additioanl power for them."

Thank you for that insight, Tharkun. Couple of Qs for ya': is there a small hand-held meter instrument to measure volume in dB in a room? Is that the same as measuring the volume of air that is being pushed from a speaker, or is that something else entirely?

Now, these Axiom 80s, they are front/left FRONT SIDE speakers, or can one (or two) of these be used for FRONT CENTER as well without compromising anything?

Also, I figured there is some difference between "200 Watts/8 Ohms" and "400 Watts/4 Ohms," just could no figure out what yet. But someone did "warn" me to use 8 Ohm or 6 Ohm resistance speakers, but not to "mess" with the 4 Ohm variety. What do you think?

To propel these larger "floorstanding" Axiom 80s, would 200 Watts per channel be enough, or would I need a beefier amp? Also, are you suggesting the use of individual (mono or stereo) amplifiers instead of a "bundled" 5.1 or 7.1 type of amp, like the OUTLAW #7700, to ward off overheating?

Also, there must be something one can do in a separate projection booth to appply direct cooling to these poor amps. Perhaps some sort of "liquid cooling" circulation, as per the tower PC variety?

Thanks!

"At the Axiom factory there are two M80s hanging from the wall about 8 feet off the ground and angled down slightly. Typical listening distance is about 30 feet and they sound great. Another vote for 2 M80s, 1 or 2 VP150s, QS8s and 2 EP500s."

Okay, but read on, bitte:

"I have a room, 30ft x 30ft x 9ft ceilings combined with a front projector Sanyo Z2 with a 2.35 screen, 51" x 120". Speakers as follows:

2 M60ti's
1 vp150
1 EP500
4 Qs8's

Feribaba, just build a stage below your screen to raise your speakers, not sure why you think you need bookshelves."

Okay, why do I think need a "bookshelf" speaker? Someone (at Axiom) might have suggested this to me last week? ;-)) This room size, as noted beforehand, is too large for HT and too small for movie theater, so it is often classified as a "post production screening room." We are talking only seating size here/room capacity, of course, not necessarily application/intended use.

Also, even though I am seeing tons of kind responses, I am still not sure how a "floorstanding" speaker can be "hung" between the floor and the ceiling? Or even if it should be.

In a cinema, the speakers are usually behind the screen, but some could be left/right/bottom as well. And they are either affixed to the back wall, or else (less frequently) mounted on a podium behind the screen. Either way, the idea is "OUT OF SIGHT."

Actually, I had thought, apparently naively, then there even could be some simple formula to calculate total and perhaps individual channel wattage requirements based on room size and room volume (app. 14.4k cu.ft. in this instance). Apparently, there is not, it is mostly a "hit or miss" game.

Perhaps there is some volume or similar handheld meter that I can get (Radio Shack??) that would give me a quick training. For example, by going to the local cinema and doing some measurements at various seats of the auditorium. Like footlambert mesaurement via a spot meter for getting that magic 16-20-25 ft.L. number prescribed by SMPTE.

Hopefully, I would not be tossed out for intellectual copyright violation in doing such a "live" measurement! ;-))

You have several questions and I'll be happy to give you my experience with my system, I do have a few questions that may aid me in a reply, would appreciate your answers.

1) Is this system for a room in your house, or is this more of a commercial application ? (48 people has me courious)

2) Do you have a ball park estimate or budget amount you are working with ?

3) You seem to be very knowledgeable on parts, but some of the basic stuff like SPL meters and wattage/ohm specifications of amps/speakers you seem to be lacking expierance with that. Do you have experience with trying to put a system together for such a large area ?

Dennis

No offense intended, as I said, I will gladly help in any way I can, but having more information from you will be of help. As I'm a bit confused as to exactly what you are attempting to put together here.

>>Okay, why do I think need a "bookshelf" speaker? Someone (at Axiom) might have suggested this to me last week? ;-))

>>Also, even though I am seeing tons of kind responses, I am still not sure how a "floorstanding" speaker can be "hung" between the floor and the ceiling? Or even if it should be.

There's a big difference between what is commonly called a "floorstanding speaker" (a generic term meaning "a big speaker, big enough that it doesn't need a stand in most applications") and "a speaker placed on the floor". You have a bigger room and a higher audience so raising the speakers seems appropriate, but they would still be referred to as "floorstanding speakers" by many even if they were floating 3 feet in the air suspended by pixie dust

>>This room size, as noted beforehand, is too large for HT and too small for movie theater, so it is often classified as a "post production screening room." We are talking only seating size here/room capacity, of course, not necessarily application/intended use.

We would call it a "big-ass home theater"

Seriously, there are a number of 30x40 home theaters with fairly large seating capacity. No problem there...

>>In a cinema, the speakers are usually behind the screen, but some could be left/right/bottom as well. And they are either affixed to the back wall, or else (less frequently) mounted on a podium behind the screen. Either way, the idea is "OUT OF SIGHT."

Out of sight is certainly doable -- placing the speakers behind an acoustically transparent curtain is not unusual, although these days most people just leave the speakers exposed 'cause they look nice and are fun to show off.

>>Actually, I had thought, apparently naively, then there even could be some simple formula to calculate total and perhaps individual channel wattage requirements based on room size and room volume (app. 14.4k cu.ft. in this instance). Apparently, there is not, it is mostly a "hit or miss" game.

There are formulas but (a) they get pretty complex, (b) they have to also include speaker sensitivity (how loud they play with a 1 watt input), room dimensions (not just volume; reflections of walls make a big difference), room construction (what the walls, floor and ceiling are made of; how they are angled, what is behind the covering), the range of angles you need to cover (function of seating layout), content (how loud the peaks are relative to normal volumes in the movies you will be showing, are you compressing or expanding the audio levels (making peaks quieter or louder respectively) etc...

>>Perhaps there is some volume or similar handheld meter that I can get (Radio Shack??) that would give me a quick training. For example, by going to the local cinema and doing some measurements at various seats of the auditorium. Like footlambert mesaurement via a spot meter for getting that magic 16-20-25 ft.L. number prescribed by SMPTE.

Yep, that's an SPL (Sound Pressure Level) meter. About $40 at Radio Shack -- that's where we normally go. If you are in Canada we're not sure if they are still available since RS has become The Source.

>>Hopefully, I would not be tossed out for intellectual copyright violation in doing such a "live" measurement! ;-))

No, but if you run into a brain-dead usher who doesn't know the difference between an SPL meter and a video camera you might have a difficult time

Screening rooms are normally painted black, right?

Black speakers will almost disappear into that sort of background, and with the lights off, no one is the wiser.

I also am inquisitive, is this for a commercial setup?