Does anyone know the theory behind the speakers used in IMAX cinemas? I know they are made by Sonics and are designed to simulate a point source. What I want is some information on how such a layout works. The subs used are a massive bank of subs that face into a slot, why? I have included a couple of pictures of their speakers so you can see what I am talking about.
Attachments
Lots of speakers are also located behind the screen. The screen actually has holes in them to let the sound pass through.
One of the reasons I can think of having bass facing the slot is to let the punch of the subs expand more evenly so that prople sitting near the speakers don't particularly feel the speakers are beside them.
One of the reasons I can think of having bass facing the slot is to let the punch of the subs expand more evenly so that prople sitting near the speakers don't particularly feel the speakers are beside them.
hi friends, i have a question, this is a loudspeaker???
Imax - Eminence 18" Speaker -- 1610022 | eBay
i need a sub and i wanna 1 imax sub
friends i'll wait your answer, thanks
Imax - Eminence 18" Speaker -- 1610022 | eBay
i need a sub and i wanna 1 imax sub
friends i'll wait your answer, thanks
Hi,
Its a raw 18" driver with no specifications, so generally not a good idea.
rgds, sreten.
Sound Re-Enforcement
Hi
For starters , you could go to the support / publication / user guide sections of jbl , ev , tannoy and read up on all they have abt installed cinema sound .
Attached here some other latest files on enclosed area sound re-enforcement to generate interest . - sorry tried uploading but the files exceed forums 195 kb limit
Plus a good book on acoustics - this is all to address ones interest in acoustics
regarding the imax , cant help much at the moment - if possible - could you get hold of the contract between imax & sonics -specially the acoustics & measurements I am posting a sample of acoustic measurements carried out prior installation in an auditorium as an sample (in the next post)
suranjan dasgupta
Hi
For starters , you could go to the support / publication / user guide sections of jbl , ev , tannoy and read up on all they have abt installed cinema sound .
Attached here some other latest files on enclosed area sound re-enforcement to generate interest . - sorry tried uploading but the files exceed forums 195 kb limit
Plus a good book on acoustics - this is all to address ones interest in acoustics
regarding the imax , cant help much at the moment - if possible - could you get hold of the contract between imax & sonics -specially the acoustics & measurements I am posting a sample of acoustic measurements carried out prior installation in an auditorium as an sample (in the next post)
suranjan dasgupta
I've seen the Imax speakers up close and they have a lot of interesting details and show evidence of good design.
The first picture shows 2 concentric horns, the treble horn is in the center of the mid horn. You can see that the horns are designed to have assymetry with a downward firing directivity. The two units seem to share the same shape, one being a scaled up version of the other. This gives them identical directivity, as you would want. I assume the foam bits help with directivity and response.
Placing the horns in the center of the mid bass, and one horn in the center of the second, is just good practice for maximizing off axis performance (least variation).
Slot loaded woofers don't change performance much but do allow for a lot of cone area in a compact volume.
David S
The first picture shows 2 concentric horns, the treble horn is in the center of the mid horn. You can see that the horns are designed to have assymetry with a downward firing directivity. The two units seem to share the same shape, one being a scaled up version of the other. This gives them identical directivity, as you would want. I assume the foam bits help with directivity and response.
Placing the horns in the center of the mid bass, and one horn in the center of the second, is just good practice for maximizing off axis performance (least variation).
Slot loaded woofers don't change performance much but do allow for a lot of cone area in a compact volume.
David S
My Sonics amps are actually Bryston 3BNRB amps with a different input module.
I'd assume they make their speakers using pro drivers from companies like Eminence and JBL etc. Then they design their own crossovers etc. My amp had active XO filters built in that were proprietary and removed before being scrapped. I would assume that much info on their speaker design is similar and they don't freely distribute their info on design.
I knew a guy who worked for IMAX. May still work for em. He used to be the guy to talk to. Everyone likes to talk a lil shop ... Maybe chatting up the sound guy at your local could garner some info?
I'd assume they make their speakers using pro drivers from companies like Eminence and JBL etc. Then they design their own crossovers etc. My amp had active XO filters built in that were proprietary and removed before being scrapped. I would assume that much info on their speaker design is similar and they don't freely distribute their info on design.
I knew a guy who worked for IMAX. May still work for em. He used to be the guy to talk to. Everyone likes to talk a lil shop ... Maybe chatting up the sound guy at your local could garner some info?
13 years on and we have a few answers. The concentric horns are interesting. Wonder what's driving the mid horn. Maybe an 8-10" cone?
Cool thanks. I followed some of those links over there, but haven't found what I was looking for yet. Will keep digging.
That thread was an interesting read, with the original designer popping in...
What were you looking for, Pano?
The answer presented itself while I typed 🙂
What were you looking for, Pano?
The answer presented itself while I typed 🙂
EarlK found it. I was probably looking right at it. 🙂
Thanks Earl!
Wonder if it's the Beta-8A in the mid horn, or a custom driver? I like the Beta-8A
Thanks Earl!
Wonder if it's the Beta-8A in the mid horn, or a custom driver? I like the Beta-8A
I was one of the contributors in that thread. I dished out everything I learned after spending years trying to restore 3 of them.
The Midrange driver is an 8" Eminence. It's custom made and good luck getting recone kits for them. Nobody will help you out. It handles 50 watts IIRC.
It's somewhere between and 8" Alpha and Beta as Eminence told me.
The Midrange driver is an 8" Eminence. It's custom made and good luck getting recone kits for them. Nobody will help you out. It handles 50 watts IIRC.
It's somewhere between and 8" Alpha and Beta as Eminence told me.
Hi
I have managed to acquire a pair of these, and although we have them working, and I have read all the other threads, has any ever had a fully working system, with the correct crossovers?
The crossover frequencies are only a very small part of the problem. What are the crossover types, what slopes are used, is any eq involved?
In measuring the 8" midrange, it is not linear anywhere near 7k. We are getting out of them at 2k.
Really like to hear these as they were meant to be.
Any additional info appreciated.
Thanks
I have managed to acquire a pair of these, and although we have them working, and I have read all the other threads, has any ever had a fully working system, with the correct crossovers?
The crossover frequencies are only a very small part of the problem. What are the crossover types, what slopes are used, is any eq involved?
In measuring the 8" midrange, it is not linear anywhere near 7k. We are getting out of them at 2k.
Really like to hear these as they were meant to be.
Any additional info appreciated.
Thanks
