Does anyone know anything about IMAX speakers?

[Woofer]

OK, so I'm about to pick up a pair of ex-IMAX speakers plus a sub.

Wot I do know, is that they 'may' have (per box), is 4x 2123 (or 2202), 2345, TAD TD-2001, and a 2245 (sub).

Wot I don't know is, what frequencies are these things crossed at, and is the model with the TAD before or after the model that had the 2404?
Also, are these things completely bi-amped or is the TAD passively x-ed?

Any IMAX specialists out there? :confused:

Cheers all.

[stephane RAME]

http://www.audioheritage.org/vbulletin/showthread.php?28766-Is-IMAX-still-using-JBL-components
http://www.audioheritage.org/vbulletin/showthread.php?26261-IMAX-cinema-sound
http://www.audioheritage.org/vbulletin/showthread.php?288-IMAX-and-JBL

Stéphane

[Woofer]

http://www.audioheritage.org/vbulletin/showthread.php?28766-Is-IMAX-still-using-JBL-components
http://www.audioheritage.org/vbulletin/showthread.php?26261-IMAX-cinema-sound
http://www.audioheritage.org/vbulletin/showthread.php?288-IMAX-and-JBL

Stéphane

I thank you for your input Stéphane, but I've read most of that, and maybe it's 'cause it's always been at the end of the day for me, generally in the very early hours of the morning, I may have overlooked the critical info that I'm after.
Believe me when I say, I've read hundreds of pages on the matter, but the thing that I can't find is the specifics of cross-over points and any time alignment adjustments if at all.
I'm about to pickup a pair of boxes plus a sub which I'm going to use for home stereo duties. Unfortunately there are no electronics with this setup, so I'm trying to figure out what and how it was done.
I do know they used Brooke Sirens crossovers, but none the wiser re: the actual cross-over points used, or whatever other post processing.
Of course I can choose my own, but I'd just like to know how they did it as a reference.
I have the Brooke Sirens (actually 9x FDS 360 x-o's, and a rack of Phase Linear 700's plus a Amcron MA-2401 to handle all the power requirements and a JBL DSC 260 if the BSS don't work out, and Klark Teknik EQ, but what are the suggested x-o points for these speakers?
I'm so exhausted from all the research I've done, and was praying someone with first hand experience with these things might step up, and add their 2 bob's worth.....

Anyway, it's almost 4.30am, and I'm all worn out and off to bed.....

Cheers....

[Jorre Pulle]

Hello there,

A few years ago I had the chance to obtain all the amplifiers from a Imax setup.
All amplifiers have internal active crossovers (via dip-switches) and are from the AB International company.
Models are:421A and 821A for the subs and model 713A for low,mids and highs.See specs on the AB-site.
Crossover points for the 713A are 800hz and 7khz.
Amplifiers were driven by (6 EA) Deq-1 Oxmoor equalizers.
The subwoofers (8 in total) were Eminence 18" (Omega Pro?) and were a replacement of JBL 18".
The other speakers were hanging on chains so i Couldn't get them to buy.
Hope I could help you a bit with my input.
Grtngs-Johan.

[Woofer]

Hello there,

A few years ago I had the chance to obtain all the amplifiers from a Imax setup.
All amplifiers have internal active crossovers (via dip-switches) and are from the AB International company.
Models are:421A and 821A for the subs and model 713A for low,mids and highs.See specs on the AB-site.
Crossover points for the 713A are 800hz and 7khz.
Amplifiers were driven by (6 EA) Deq-1 Oxmoor equalizers.
The subwoofers (8 in total) were Eminence 18" (Omega Pro?) and were a replacement of JBL 18".
The other speakers were hanging on chains so i Couldn't get them to buy.
Hope I could help you a bit with my input.
Grtngs-Johan.

Thank you Johan for your very valued input.

So it would seem that there can be quite a variation regarding amps and speakers.
The ones I'm picking up tomorrow are all JBL components except for the ultra highs. (TAD TD-2001) Apparently the JBL 2104 seems to be the 'normal' driver used instead of the TAD now. (someone feel free to correct me if I'm wrong.)

The amplifiers that were used with this particular setup are the Sonics 800x, but are not available now as they were sold off separately.

http://img221.imageshack.us/img221/159/imax3wayspeakerboxes.jpg

(... and yes, for those 'eagle-eyed' amongst you, it is a pic of one 'mirrored' for effect, but I'll post proper pics after I've picked 'em up.)
:bouncy:

[Lee in Montreal]

And how many 2245s did you get? :D http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=41758&stc=1&d=1252530013 http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=41759&stc=1&d=1252530038

[Woofer]

And how many 2245s did you get? :D

(sob, sob) ..... just the one. :crying:
.... so far. :o:

[rlsound]

Are you sure there are JBL drivers in those? I'm restoring a set and they use Eminence drivers for the cones and TAD, B&C, or Celestion for the HF.

[Woofer]

Are you sure there are JBL drivers in those? I'm restoring a set and they use Eminence drivers for the cones and TAD, B&C, or Celestion for the HF.

Hmmmmm.........
Now THAT'S thrown a cat amongst the pigeons!
.... and could very well explain a few things.
After reading lots n' lots n' lots n' LOTS..... I've generally found reference only to JBL components, but had never found any reference to these boxes even having TAD or anything else for that matter.
All the references I've found regarding what's in them is as I have mentioned in my first post.
Now, not only your good self, but Jorre Pulle (Johan) has also mentioned the same thing.
I won't know for certain until late tomorrow afternoon when I go to pick them up.
Right now, the only thing I am certain of is that this particular pair have the TAD TD-2001. The rest is yet to be ascertained upon further investigation tomorrow.
It's going to be a difficult judgement call, as the TAD's alone are worth the price of what I'm paying for the whole lot. (2 boxes and a sub)
We shall see what happens tomorrow then.

Thank you so much for that extra info rlsound. It's very much appreciated.

I'll post an update as soon as I know what's going on.

Cheers all :)

ps: .... and yes, after a closer look at the above pic, they don't look like the 2202 (or the 2123, which was another JBL used), do they? The dustcaps are a little too big and hide the wire 'lead ins'. :(

[Ruediger]

The Munich IMAX seemed to use stock JBL components.

Only the 2404s they used had been modified. They had a long pipe between motor and horn to get the "acoustical centers" of the different speakers into one plane.

Are You sure that the stuff You are going to buy is IMAX stuff?

A discotheque comes two my mind, where a "helpful technician" had diagnosed the 2405s as defect, and had swapped them for little money against piezos. He took the 2405s home, of course.

ruediger

[Woofer]

The Munich IMAX seemed to use stock JBL components.

Only the 2404s they used had been modified. They had a long pipe between motor and horn to get the "acoustical centers" of the different speakers into one plane.

Are You sure that the stuff You are going to buy is IMAX stuff?

A discotheque comes two my mind, where a "helpful technician" had diagnosed the 2405s as defect, and had swapped them for little money against piezos. He took the 2405s home, of course.

ruediger

Yes Ruediger, it is definitely IMAX.

They were all pulled from an IMAX theatre. (along with at least another 4 boxes, which makes it a total of six, which is a standard IMAX setup.
(left rear, left front, centre, one flown above centre, right front, right rear, and a special room that's tuned like a giant bass enclosure with 8 subs in it installed below the centre box.)

I have seen an IMAX box from various sources on the 'net and they compare favourably with the above photo.

There seems to be up to three different versions from what I've found so far, but the one thing they all have in common, is the actual box, (and the horns.)
The drivers can vary, but the basic box is the same throughout....

In another 12 hours, I'll know more.... (and I'm counting the minutes.)

:)

[rlsound]

The references you have read about JBL and IMAX are referring to the older systems that used four way clusters. These speakers you and i have are a very different beast. There are two different models, the SR (which is only the horns) and the GT, which is the model you have purchased. All IMAX theaters from 1998 until 2004 used these until the MPX line was developed. Aside from the four way JBL stack, the GT speakers are the best they have.

The do use a passive crossover for the high-mid, but the woofers are powered separately making it biamped

[Woofer]

The references you have read about JBL and IMAX are referring to the older systems that used four way clusters. These speakers you and i have are a very different beast. There are two different models, the SR (which is only the horns) and the GT, which is the model you have purchased. All IMAX theaters from 1998 until 2004 used these until the MPX line was developed. Aside from the four way JBL stack, the GT speakers are the best they have.

The do use a passive crossover for the high-mid, but the woofers are powered separately making it biamped

That bit of info is 'gold', as I'm about to leave in an hour or so to do the deal....
The current owner has been anything but forthright with info about this lot, and I've spent countless hours sifting through search results.
At least now, after everybody's input, I'll be able to make a final decision on these things once I'm there.
The offer currently stands at AU$2500 for the two boxes plus one sub.
At least these have the TAD TD-2001 which can sell for up to $2500 on their own, so the overall deal still looks worthy, but I'm still none the wiser as to what the other compression driver is or even what the sub is for that matter, but I'll know soon enough.
Thanks heaps once again..... ;)

[Woofer]

UDATE: To those that might like to know.

Got 'em.
They're in the back of the van, and that's where they'll stay for a couple of days.....
I'm just too buggered, plus I underestimated how much room they'll need to set up.
Ended up getting the two boxes plus two subs which are way bigger than I imagined, and I mean really really big. A good match I think/hope.
Most importantly, they do have the TAD TD-2001, and yes, as stated by others, not a JBL anywhere.
Interesting midrange setup, using a small (5" ?) cone driver coupled to the bigger of the two horns.
I'll get some pics organised in a couple of days.

HUGE "THANK YOU" to those who have added their experiences and opinions.

All my best to all....

Woof. ;)

[Jorre Pulle]

Hi woof,
I am awaiting the pictures of your catch.
Hope you are happy with the new "stuff".
What brand are the "not JBL" then?
Grtngs;
Johan.

[Woofer]

Hi woof,
I am awaiting the pictures of your catch.
Hope you are happy with the new "stuff".
What brand are the "not JBL" then?
Grtngs;
Johan.

Hello Johan,

They are almost exactly what rlsound suggested, being Eminence speakers, I think. I didn't see any brand names on any drivers except for the TADs. I'll check more closely in the days to come.
So therefore they could be the GT series.
The only difference is that they do not have any passive x-o's between the mids and highs.
Totally active crossed boxes. There is a terminal strip at the back right hand side of the box that connects to the mids and highs, plus two lots of connections for the two pairs of 12".
I'll get some pics in a couple of days. There's just too much work to do, and we're currently experiencing a heat wave for the next WEEK! So no hurry to do anything with them right now. They can stay where they are for a little while.
;)

[SEAWOLF97]

great find Woofer ..congrats :applaud:

[Woofer]

great find Woofer ..congrats :applaud:

Heh, heh. Yeh, I'm clapping and patting myself on the head at the same time!

Thanks SEAWOLF' ;)

[rlsound]

The mid range is an 8 inch driver, also eminence. The polarity is reversed on it, make sure positive is going to the negative terminal.

[rlsound]

What kind of subs did you get? If you get a chance to snap some pics I'd appreciate it.

[Woofer]

What kind of subs did you get? If you get a chance to snap some pics I'd appreciate it.

The 18" speakers in the subs appear to be of the same make as the 12" and 8" so I'm guessing they're Eminence too.
The sub boxes are extremely large, probably 4 feet deep or so.
I'll measure up the lot properly eventually and post my findings.
As mentioned previously, pics to follow in a few days.
The whole exercise has been most exhausting so I'm resting for a while...... :o:

[Woofer]

Hello there,


Models are:421A and 821A for the subs and model 713A for low,mids and highs.See specs on the AB-site.
Crossover points for the 713A are 800hz and 7khz.

Grtngs-Johan.

Johan, (or anyone else for that matter), do you know what the crossover point is for the subs please?

Woofer.

[Jorre Pulle]

Hello to all,
As i said before my sub amplifiers are AB International model 421A (1CH mono) and model 821A (2CH mono).
All the amp-specs can be found on their website and their support is very good.
The active crossovers in the amps have a lot of possible settings.
Bandpass settings are between 20-30hz to 50-80hz,combined with the Oxmoor equalizers one can see the possibilities.
Although i have the Imax 18" woofers (Eminence) I use a JBL 2240H at home.
All depends on the woofer-brand you have now and the enclosure model and tuning freq,i think a bit of experimenting is in order.
I was told that tuning a Imax set up took more than a week,don't know if that is true.
Greetings and have fun.
Johan

[Jorre Pulle]

Hello i quickly took some pics of the 18" Imax woofer,the other picture is just for fun.
Bottom amp is a BGW 750G.
Grtngs-Johan.

[Woofer]

Thank you Johan,
(extra thanks for posting the pics too!)

I have been swamped with my searching out this subject so a link to the exact reference would've been good.

So, I'll be a little more specific.

Does anybody know what was the x-o point used with the IMAX Eminence subs/speakers Theatre installations?
IMAX owned a company called Sonics who built the boxes and contracted out for their amplifiers.
At some time, they used Sonics 800x power amps (which in reality were a re-badged Bryston 7b) for their installs before the AB.
The choice of amplifiers is a bit of a mystery as to what and when they were used. Not even their site elaborates on what was done when.

... and yes, I know I can experiment to my heart's delight, but I would like to add the correct specs to my database for reference.

Anyone? Please?

[yrrab07]

Hi all,
I picked these up last week (literally in the theater) from a local IMAX Theater that upgraded their system. I’m glad I found this thread because there is little to no information available on the web. Four of the same boxes Woofer picked up with three Subs. The sub is an 18” Eminence but anxious to see what Woofer discovers in the large box. He’s probably nursing sore joints and muscles like me because these things are really heavy..
Sub box dimensions - 33” tall, 44” deep and 21” wide

Main box dimensions – 50” tall, 23.5” deep and 30” wide

[Woofer]

Hi all,
I picked these up last week (literally in the theater) from a local IMAX Theater that upgraded their system. I’m glad I found this thread because there is little to no information available on the web. Four of the same boxes Woofer picked up with three Subs. The sub is an 18” Eminence but anxious to see what Woofer discovers in the large box. He’s probably nursing sore joints and muscles like me because these things are really heavy..
Sub box dimensions - 33” tall, 44” deep and 21” wide

Main box dimensions – 50” tall, 23.5” deep and 30” wide

Nice one yrrab'

Welcome to the thread......

As promised, here's some extra home snaps to look at.

http://img607.imageshack.us/img607/7136/imax1.jpg

http://img255.imageshack.us/img255/1204/imax2l.jpg

... and now for some pics especially for rlsound, ;)

http://img839.imageshack.us/img839/1913/imax3.jpg

http://img703.imageshack.us/img703/543/imax4.jpg

http://img203.imageshack.us/img203/8416/imax5.jpg

http://img842.imageshack.us/img842/2476/imax6.jpg

:bouncy:

[Lee in Montreal]

but I would like to add the correct specs to my database for reference.

Anyone? Please?

Well, here lies your answer as for the subs. Dipswitches dont' lie. Cut-off and bump.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=58369&stc=1&d=1363077598

[Woofer]

Well, here lies your answer as for the subs. Dipswitches dont' lie. Cut-off and bump.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=58369&stc=1&d=1363077598

So that means what? 80Hz?

[Lee in Montreal]

So that means what? 80Hz?
You can probably source the manual for that amp in order to see how the dipswitches are set. That shall tell what the settings are according to the picture.

And a link - http://www.abamps.net/

[Woofer]

You can probably source the manual for that amp in order to see how the dipswitches are set. That shall tell what the settings are according to the picture.

And a link - http://www.abamps.net/

Yeh, thanks Lee.
That was mentioned earlier, (but no link tho'), but at the time I'd already spent a hundred plus hours sifting through billions of pages, and I just wished someone would just simply tell me.....
I'm just so exhausted from it all. I'm an old man now, and I just don't have the stamina I used to.

Anyway, enough for today. It's after 3.30am, and I'm off to bed.....

[Jorre Pulle]

http://www.abamps.com/

Operator manuals and specs can be found in "Product Archive" and then "ATD Series".
Sub amps used in Imax are model 821 and 421,low-mid-high amps are 713A.

Grtngs-Johan

[Woofer]

http://www.abamps.com/

Operator manuals and specs can be found in "Product Archive" and then "ATD Series".
Amps used in Imax are model 821 and 421.

Grtngs-Johan

(.... almost gone to bed)

Yes Johan, you just beat me to it. I was about to post that too! ;)

The pdf can be found here: http://www.abamps.com/pdfs/421a.pdf

.... going going gone!

[rlsound]

Mmm thanks for the IMAX porn gentlemen, made my day!

Remember, IMAX uses bass management so the subwoofer is matrix created from the main channels. 80hz would be a good spot to start, i can't see 12s playing down that low for dialog

[Woofer]

Mmm thanks for the IMAX porn gentlemen, made my day!

Remember, IMAX uses bass management so the subwoofer is matrix created from the main channels. 80hz would be a good spot to start, i can't see 12s playing down that low for dialog

My sentiments also.

[yrrab07]

Here's what they look like cleaned up! It took some research to find materials and many hours of labor but they are dang sexy..

[Lee in Montreal]

Looking good. So, you have 4 subs and 4 mid/highs to pressurize a storage locker? How wil you treat those galvanized panels? :bouncy:

[Woofer]

..... all you need now yrrab07 is a truckload of power amps and a 3 phase power distribution board and you're away! LoL
Finally got around to installing them in the studio, and after a bit of tuning, they sound superb, and at any volume be it high or low.
A bit of a problem with a lack of 2.5K, but that's all fixed now with slapping a Klark Teknik parametric across them.
A very nice system and appreciated immensely by all that have heard them so far.

[Woofer]

Well, the story continues......
Just been re-offered the original 3 pairs of power amps (Bryston 7B Mono amps, rebadged as Sonics 800x by IMAX) for $1000 the lot. (yes, that's SIX 7B's at under $170 a piece!)
Wot to do?????

[Lee in Montreal]

Wot to do????? Do you really want me to knock you on the back of the head? Come on. Go get them. This is dirt cheap power, and original at that.

[Woofer]

Do you really want me to knock you on the back of the head? Come on. Go get them. This is dirt cheap power, and original at that.

Heh heh heh..... Yeh, I needed that Lee. ;)
I'm just waiting for daylight now, so I can finalise the deal, on the amps mentioned (all six), plus another IMAX box and two more subs.
(it's 2.30am right now, so not really a good time to do anything more but wait..... anxiously.)

[Woofer]

UDATE:

A reply from Bryston...


"We did indeed manufacture the Sonics 800X for Sonics, who supplied the sound systems for IMAX. The units were roughly equivalent to a 7B NRB, but had a modular input board/rear panel, to allow filtering and other processing specific to the application. Depending on the rear panel module installed, they could be used as a mono or stereo amp.




Some units also had limiters built in to the channels, which is great in a theatre application, but may not be great for home Hi Fi."

[yrrab07]

I'm looking for a place to sell these bad boys! Any suggestions? There are four component speakers and three subs. Picked them up in person from the IMAX Theater. Thanks5915159152

[Woofer]

Wow! They look to be in awesome condition.

Maybe you could split it into two separate systems, but obviously one with one sub and the other with two, or you could have two systems with one sub a piece, (it's enough), and sell off the other as a single sub.

Be aware that these subs are going for as little as $300 each, or less, these days.
They only (usually) have an Eminence 18" in them which sell really cheaply on the 'Bay on their own.
Last one I saw went for only around $130.

BTW, which drivers do your hi/mid boxes have? Is there a TAD 2001 for highs in there or something else?

Cheers,
George.

[yrrab07]

Hi George,

Thanks for the suggestion of splitting them up! I am a bit surprised to hear the subs go for so little considering the boxes alone had to cost hundreds to build. The Hi's are driven by a TAD TD2001 with an 8" mid is pushing the larger horn.

Barry

[Woofer]

Hi George,

Thanks for the suggestion of splitting them up! I am a bit surprised to hear the subs go for so little considering the boxes alone had to cost hundreds to build. The Hi's are driven by a TAD TD2001 with an 8" mid is pushing the larger horn.

Barry

Yes I know, Barry, but nothing makes sense anymore....

http://www.ebay.com/itm/18-inch-Imax-Sub-/121121780093?pt=AU_Hi_Fi_Speakers&hash=item1c336bb17d&_uhb=1

Got it for the initial opening bid of $AU$350. ;)
Sadly, you can get more for a pair of TAD's (on their own) than what you can get for the complete pair of boxes.

George. :(

[Jorre Pulle]

Hi woof,

Would like to see some pics of those amps when you get them.
Mine are all AB International and perform very good.
Grtngs;
Jorre-Belgium

[Woofer]

Here's the pair of them, Sonics 800x, (although in reality, a pair of Bryston 7B, as confirmed by the good people at Bryston, - g'day Mike :wave:), on the floor with a little 2x 12AU7 pre-amp running them, before I changed one to stereo. (that's a 240V to 110 V stepdown transformer next to them in case anyone is curious).


http://imageshack.us/a/img248/8549/hereitisv.jpg

.... now they're on top of my sub (for a while), and all hooked up to stuff.

http://img594.imageshack.us/img594/5956/hereitis2.jpg

.... and this is what one looks like inside.

http://imageshack.us/a/img836/3692/7binside.jpg

.... and here is its very plain back panel (module). Just an In and an Out, and Speaker O/P's.

http://img703.imageshack.us/img703/1439/hereitis2bp.jpg


So for now, I've got the stereo one connected to a pair JBL 4313B's, and the mono block one connected to my JBL B380, using the BX63A as a x-over, and the 12AU7 thingie as a pre-amp, fed from an old AMC DAC being fed by my iMac.

Sounds pretty good.....
.... and whole thing's as quiet as a mouse. No loops or buzzes or anything.

I'm giving this whole IMAX thing a bit of a rest, so I thought I'd fiddle with the amps for a while. :bouncy:

[Jorre Pulle]

Hello George;

Thanks for posting the pics.
The amps look well made;did you drive them into a dummy load and what about cooling?
Grtngs Johan.

[Woofer]

Hello George;

Thanks for posting the pics.
The amps look well made;did you drive them into a dummy load and what about cooling?
Grtngs Johan.

No Johan, no dummy loads.
Just hooked it up, turned it on and let it 'fly'.
It has adequate heat sinks along the sides, (no fan) and after running all day, only got slightly warm.

BTW, someone just sold one of these in Florida for only $135 last week! Funny what a difference a badge makes.
If it had Bryston on it, it would have sold for $1000+

George.

[jasonski73]

Hi there
I actually have the matching Bryston/Sonics 600x power amps with sonics 3way active crossover modules fitted
the amp section looks very similar to the 5b-st 3 channel power amp I can upload some pics if you like? I have six in total 5 working and 1 with bulging caps.
I bought 18 of these amps 12x 800x's and 6x 600x's ( sold a few 800x's)
I'also trying to find out the crossover points on the xover module.
what little I do know is that the 600x is a three channel amp with only 2 sets of speaker terminal outs one is H/F other is M/H and a balance mono L/F out that goes to another power amp to deal with the bass side of things. the mid output is bridged so i guess its outputting 250 watt for mid and 120 watt for H/F.

I'm hoping that once I know the xover points I will use 2 800xs and 2 600x's for some diy speaker project

If I can help in any way let me know cheers

[Woofer]

A most valuable addition to the thread.
Thank you so much for your input.
Yes, photos are always most welcome. :bouncy:

It's all coming together slowly, but surely.

(ps: the x-o points seem to be 80Hz, 800Hz, and 7KHz. Check post #4)

[jasonski73]

Here's the pictures of the 600x internals etc
you can see the large dual pcb which is the crossover board .. enjoy

[Woofer]

Thank you, thank you, thank you Jason.
Your efforts are extremely appreciated.

George. :bouncy:

BTW: Schematics and manuals are available from Bryston archived section, here:
http://bryston.com/pages/technical.html

[Jorre Pulle]

Hello there;

Here some pics to feed the topic.
Grtngs;
Johan

[mrjschmitz]

Hi there
I actually have the matching Bryston/Sonics 600x power amps with sonics 3way active crossover modules fitted
the amp section looks very similar to the 5b-st 3 channel power amp I can upload some pics if you like? I have six in total 5 working and 1 with bulging caps.
I bought 18 of these amps 12x 800x's and 6x 600x's ( sold a few 800x's)
I'also trying to find out the crossover points on the xover module.
what little I do know is that the 600x is a three channel amp with only 2 sets of speaker terminal outs one is H/F other is M/H and a balance mono L/F out that goes to another power amp to deal with the bass side of things. the mid output is bridged so i guess its outputting 250 watt for mid and 120 watt for H/F.

I'm hoping that once I know the xover points I will use 2 800xs and 2 600x's for some diy speaker project

If I can help in any way let me know cheers

Jason!

Do you have any spares for sale?

I'm desperate to buy some!

Thanks

John

[Jorre Pulle]

Hello to all,

I am still looking for the Pa-422 interface to program my 6 Imax equalizers from Oxmoor.
It can be done via buttons on the internal Pcb,but with that Interface the job can be done with a laptop and the Oxmoor software.
So if someone has a spare Interface please let me know.

Grtngs;
Johan

[Woofer]

Nice pictures Johan.

Big difference between the Sonics 800x/600x's and the AB's. No such luxury with the Sonics. Not a dip switch in sight.

Re: Oxmoors, I only have a single DEQ-1 (same as yours by the sound of it), but I'd be interested in getting another one.
Don't know what happened to the rest, but there was only one in the pile by the time I got to it.
It's a good thing they can be set internally, otherwise they'd be unusable otherwise.

Message to John:

I'm not quite sure of what you mean with your request for spares.
If you're talking 'spare' amplifiers, then be careful when buying a Sonics 800x/600x. Some, like mine, do not have dual voltage capability, even though they were used in an Australian IMAX theatre, (we're 240V), and I've had to resort to using Step-down transformers, (240V to 110V).
Just thought I'd mention it.

Anyway, off to bed.....

[mrjschmitz]

Nice pictures Johan.

Big difference between the Sonics 800x/600x's and the AB's. No such luxury with the Sonics. Not a dip switch in sight.

Re: Oxmoors, I only have a single DEQ-1 (same as yours by the sound of it), but I'd be interested in getting another one.
Don't know what happened to the rest, but there was only one in the pile by the time I got to it.
It's a good thing they can be set internally, otherwise they'd be unusable otherwise.

Message to John:

I'm not quite sure of what you mean with your request for spares.
If you're talking 'spare' amplifiers, then be careful when buying a Sonics 800x/600x. Some, like mine, do not have dual voltage capability, even though they were used in an Australian IMAX theatre, (we're 240V), and I've had to resort to using Step-down transformers, (240V to 110V).
Just thought I'd mention it.

Anyway, off to bed.....

Thanks woofer

Yup, I was aware of that issue. There was a European version I think with 240v but I'll take anything I can get my hands on. Using a transformer doesnt worry me as long as it doesnt affect sound quality?

Yeah, I'd love to get my hands on an 800x if someone has got one? Does anyone know what equivalent Bryston model the 600x are? I think they are a three channel? Any of the Bryston experts know?

Thanks

John

[Woofer]

John,

The 600x is the 5B.
... and yes, they are a 3 channel, but two of them are bridged.

Woof.

[mrjschmitz]

John,

The 600x is the 5B.
... and yes, they are a 3 channel, but two of them are bridged.

Woof.

Do you think it is possible to unbridge them and use them as normal 3 channel amps?

Thanks

John

[Woofer]

Do you think it is possible to unbridge them and use them as normal 3 channel amps?

Thanks

John

I just don't know, yet.....

[Woofer]

Two more pics of the back of the boxes showing the TAD (with the 8" removed), and crossover.

http://img266.imageshack.us/img266/7627/wpo8.jpg

http://img832.imageshack.us/img832/9002/hbk0.jpg

[Woofer]

Here's an interesting claim, in this Altec 617-8A listing:

http://www.gumtree.com.au/s-ad/high-wycombe/audio/altec-duplex-617-8a-speakers/1031038321

The seller states,

ALTEC DUPLEX 617-8A SPEAKERS by Sonics Associates Inc. for IMAX® 3D..

Does any one know if this is correct, and which year models were they used in?
It seems a bit unlikely given that I thought the 617 wouldn't have been produced any more at the time the IMAX were made, or were they?

Any input most appreciated.

[Jay Mitchell]

I am the designer of the IMAX PPS (Proportional Point Source) theater loudspeakers and associated active crossovers. I came across this thread and joined the forum to provide correct information about these speakers.


Two more pics of the back of the boxes showing the TAD (with the 8" removed), and crossover.The components on the PC board are for DC protection only. The crossovers were entirely active and were integral with the power amplifiers.

The polarity "reversal" on the 8" midrange driver - which only applies to the larger version of the speaker with 4x12 LF transducers - is to account for its physical reversal: it is mounted with its magnet forward. The same transducer in the smaller version, which employed 2 12" LF transducers firing through slots - was mounted and wired conventionally.

With the exception of the TAD 2001 HF driver, the transducers in the PPS speaker were produced for Sonics on an OEM basis by Eminence. Other than the HF driver, which was TAD only, my specifications for the design included approved transducers from three manufacturers: JBL, Cetec Gauss, and Eminence. JBL discontinued the 12" drivers in the LF section and Sonics encountered some issues with the JBL 8" driver called out for the midrange. Mark IV Audio acquired the Cetec Group, moved transducer manufacturing to an EV plant in Tennessee, and immediately began using different parts to make Gauss transducers. At that point, the only manufacturer whose parts were compliant with the specification was Eminence, so Sonics went with them. To my knowledge, those components were unchanged for the production life of the design. IMAX dissolved Sonics ca. 2002 (+/- a year or two), at which time production of the PPS system ceased. At that time, sufficient inventory of those systems had been amassed to supply new theaters for the next 3-4 years.

[1audiohack]

Hello Jay;

Welcome!

From one who is interested in large format cinema sound systems, thank you!

All the best,
Barry.

[Woofer]

Hello Jay,

.... and I'll join Barry, in offering a HUGE "WELCOME" from me too!

Thank you so much for your most valuable input.
As you must know, reliable source material on the IMAX boxes is pretty hard to come by even with the 'net being what it is.
I am honoured that you (being the Designer of these magic boxes), have added your "two bob's" worth to the thread.
There's a few of us out there now, and on behalf of all of 'em, please don't hesitate to add anything extra that comes to mind.
.... and if there's anything else in this thread that needs correcting, don't hesitate in setting the records straight.

George. :bouncy:

[rlsound]

A BIG welcome to Jay!

[Woofer]

@Jay,

What was the 'design philosophy' behind that box?
What gave you the idea to create a composite box of that particular design?
Were you trying to create something point source e.g. like a giant Altec 604 or a Tannoy speaker etc?
Did it take a long time to come up with that final design?
Sorry for all the questions. (If you were me, you'd understand.... :o: )

I still can't believe at how good they sound, at any level, and any distance.
You should be proud.... :)

[Jay Mitchell]

There was then and is now no single element in my design philosophy that overrides all else. Details matter. A common element in all of my designs - predating the PPS and continuing to this day - is the concept of a multiway loudspeaker that performs as a single, very well-behaved full range source. The specifics of the design of the IMAX PPS speaker - which include the horn shapes and the configuration of the LF section - were driven by a recognition that, for a multichannel sound system to be effective, the relative levels and responses of each channel as presented to any given seat need to be as well-matched as possible. Within the constraint that all six speakers had to be the same design (an argument could be made that six different designs would be ideal), we were successful in achieving that goal. The R&D process that led to the PPS design included a preliminary revision of the existing design followed by a completely new design. The initial redesign took about a year, and the all-new PPS was in production a little over two years after that.

[mikebake]

Like.

[Woofer]

Jay,

Thanks heaps for the extra input. :)

I have yet to see a spec sheet for ANYTHING to do with the Audio set-up for an IMAX Theatre.
..... and I've spent hundreds of hours looking.
Is there one that you could possibly share? (eg: frequency response, SPL figures etc.)

In regards to once you had designed and built what you wanted and finally installed it all in a theatre, after walking around the room, what were your first impressions, (if you can still remember back that far?), and was there a sweet-spot in the room, and more importantly where was it? (for next time I go to an IMAX theatre). ;)

Was there anything you weren't happy with, and took it all back to the drawing board and started again?

Just one more thing (sorry), but how did you come up with the concept of building a separate room to put the subs in, (dimensions if you could, please), and then use the whole thing as one giant sub? That's just brilliant!

G.

ps: There's been just one more thing that's been confusing me..... (yes, it doesn't take much :( )

HOW do the boxes get powered up?
OK, we have the Sonics 600X (running in TWO channel mode) with the in-built cross-over and the LOW split out of the back to obviously an 800X, but that still only gives you THREE Way. If the system is FOUR Way, including the Subs, where does the 'other' (SUB) band-passed signal come from and what amp does it go to? Another 800X?
So is there one 600X and two 800X per channel?
(600X High and Mid, 800X Low, 800X Sub)
Damn.... now even I'M confused.....

[Jay Mitchell]

IMAX never published specifications for theater acoustics or sound systems. The information was proprietary. They didn't even sell projectors or sound systems: they only leased those items.

There was never any doubt of the results we would achieve in the development process that led to the PPS loudspeaker design. We did enough advance analysis and testing - both in laboratory and in theater environments - to ensure that there were no surprises. The results were as expected.

As for a "sweet spot," projection quality is more definitive of that than sound quality. When you sit in extreme left or right positions - especially in the front rows - there is inevitably distortion of the image. For that reason, I suggest selection a central seating position - possibly just rearward of the center rows of seats - for the best visual experience. BTW, this applies to all movie formats, not just to IMAX.

The subbass array is driven from a completely separate signal chain than the channel signals. First, each channel signal is routed through highpass and lowpass filters. The highpass outputs are sent to their respective speakers. The lowpass outputs are mixed and send to the subbass amp racks. You will need another amp and additional filtering to drive a subwoofer, but the bandwidth of the main speaker is enough that subbass won't really be necessary in a residential sound system.

[Woofer]

The subbass array is driven from a completely separate signal chain than the channel signals.

.... and THAT'S the very bit of key info I was looking for Jay.

So that means, you have ONE 600x for the highs, and the mids, (utilising the internal x-over), then link out of that 600x to an 800x for one pair of 12", then link out of that 800x to ANOTHER 800x for the 'other' pair of 12", and so powering just the ONE box, right?
One box = 1x 600x, 2x 800x.
Then you run another 800x for the Sub, but fed from a separate filtered feed.
I just knew there had to be another x-over (of sorts) involved....

Thanx heaps..... :bouncy:

[badman]

Hi Jay:

First, thanks for contributing. Interesting design. Second, are you still with IMAX? Is there anything you can disclose about your current designs?

[Jay Mitchell]

So that means, you have ONE 600x for the highs, and the mids, (utilising the internal x-over),No. See my original post in the thread. There is no internal crossover. All crossover functions are active. The amps are all stereo. Half of a 600x drives the HF, the other half drives the MF. The 800x drives all four 12s, two per channel.

[Woofer]

No. See my original post in the thread. There is no internal crossover. All crossover functions are active. The amps are all stereo. Half of a 600x drives the HF, the other half drives the MF. The 800x drives all four 12s, two per channel.


I'll tell you what I have.....

I have 600x amps that are 3 channel, with two being bridged internally and only have one signal input and a Low signal output, plus a pair of speaker outs on the back panel. (one has a white terminal (Highs), and the other has black (Mids) for the -(ve) connections, but both still having matching red terminals for the +(ve) connections.)
One side for highs (L) 125W (8 Ohms), the other for mids (R) 250W (8 Ohms).
There is also a 3-way Active X-over card (band pass filter, call it what you will), built into the unit. It is made and branded by Sonics.
It feeds the 'two' channels in the 600x, with, as mentioned, a separate link on the back panel for the 'lows' signal output.
The 800x amps are bridged Mono blocks (800W into 4 Ohm). Each has an input for the 600x 'low' output link, and then there's another link OUT to connect to a 'slaved' 800x to power up the second pair of 12"
With my setup, I have one 600x powering the mid and highs, and TWO 800x each feeding a pair of 12" (per channel. That's 3 Amps per box. Obviously the same again for the other channel, as I'm only running stereo at the moment.)

Post #48, 4th pic shows two of my 800x amps I'm currently using at home on another stereo, of which one 800x has been converted back to stereo (top one), and the bottom 800x I'm using for my sub.
I did this after consulting with Bryston, who graciously told me how. (Love those guys at Bryston's.) :bouncy:

In Post #53, first pic, shows the different colour connectors used for the 600x and the labelling says that there's an internal 3-way crossover module, which if you look at the following pic, there it is...

So forgive me Jay if I find your comment "There is no internal crossover", confusing..... :confused:

Then there's the Subs, each with it's own bridged 800x... but that's another story.

G. :)

[Jay Mitchell]

There is also a 3-way Active X-over card (band pass filter, call it what you will), built into the unit. It is made and branded by Sonics.I designed that. It is essential to the proper function of a PPS loudspeaker.


So forgive me Jay if I find your comment "There is no internal crossover", confusing..... :confused:You had earlier mistakenly called the DC-blocking caps on the circuit board a "crossover." It was my impression - which turns out also to be mistaken - that you were referring to this board when you spoke of an internal crossover.

[Woofer]

I designed that. It is essential to the proper function of a PPS loudspeaker.

You had earlier mistakenly called the DC-blocking caps on the circuit board a "crossover." It was my impression - which turns out also to be mistaken - that you were referring to this board when you spoke of an internal crossover.

Mine were all too noisy, and I've bypassed them and now using Brooke Sirens crossovers....
If I could find schematics for the 600x x-o's, I'd try to fix them but I can't.
The BSS sound just great so it's solved my problem.

[Jay Mitchell]

Mine were all too noisy,What kind of noise, and which channels (low, mid, high?). Those boards were extremely quiet by design, and maximum noise levels were strictly enforced in QC.


and I've bypassed them and now using Brooke Sirens crossovers....Then you don't have PPS loudspeakers any more. The crossover - which does a lot more than just divide the spectrum - is an integral part of the design. The highpass/lowpass filters are themselves unique, and there are other essential functions that a storebought crossover can't provide.


If I could find schematics for the 600x x-o's, I'd try to fix them but I can't.I just dug through my archives and found schematics from the original spin of the crossover. I'll scan the sheets next chance I get. If you'll send me a PM with an email address, I'll send them to you. It may take awhile, because other items on my to-do have higher priority.


The BSS sound just great so it's solved my problem.There's no way the speaker works (meaning sounds) as designed with an off-the-shelf crossover. If you can get the correct crossover repaired, the speakers will sound much better.

[Woofer]

Thank you Jay.
I've PM'ed you.
Talk soon.

All the best.

G.

[Lee in Montreal]

Wondering if anyone has the outside measurements for the subs?

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=59152&d=1370718623

Lee

[Woofer]

Here's a copy of the schematics for the Sonics 600x crossover graciously made available by Jay.

https://dl.dropboxusercontent.com/u/46689525/PPS%20Xover.pdf

Cheers all.


*Note to Lee:

I put forward your question to my mate Ged, who has all the IMAX stuff in his studio.
Just waiting for a reply.

G.

[Eaulive]

So cool when you get to actually talk with the designers :D:applaud:

[Jorre Pulle]

Good evening to woofer and to all;

Could you ask your mate Ged if he has the schematic of the PA-422 interface to program those DEQ-1 of Oxmoor?
I have 6 of DEQ-1 and they are a bit hard to program without that interface.
My amps are of AB international with built-in active crossovers.


Grtngs Johan-Belgium.

[Woofer]

Good evening to woofer and to all;

Could you ask your mate Ged if he has the schematic of the PA-422 interface to program those DEQ-1 of Oxmoor?
I have 6 of DEQ-1 and they are a bit hard to program without that interface.
My amps are of AB international with built-in active crossovers.


Grtngs Johan-Belgium.



Hello Johan,

Unfortunately, no. Don't have the interface, or schematics, but the DEQ-1 is very easy to program without one.
It's a little bit inconvenient, to have to pop the lid off to do it, but other than that, they are very easy to set up.


Cheers,
George.

[Joseph]

Hi to all
I found this thread today by accident while searching Jbl.
Tests I made seated at the center,five seats down from the back I have tested a sound level of 82dB to 85db continuous and between 110dB to 118dB peak. (GT IMAX)

Did you get the panels for the side of the box the two panels is part of the speaker they are there to direct low tones forward.


You guys said the crossover frequency is 80hz,800hz and 7000hz IS THAT CORRECT? For that GT
PPS enclosure.
Most 8 inches speaker reaches a maximum of 5000hz. 7000Hz is 2000hz higher than the 8 inch speaker range.


80Hz lowpass for the sub,
800hz lowpass for the 4 12s,
800hz to 7000hz bandpass for the 8 inch. 2000Hz more.
7000hz highpass for the high frequency driver.


Woofer you said you got a problem with a lack of 2.5K. That is a drawback of a constant directivity

horn. constant directivity horn has a dip in frequency between 2k to 5k.
From the above I think the mid horn is a constant directivity horn.


A constant directivity horn is to provide the same volume (SPL) at all frequencies for the coverage area. Sounds pretty much like a (PPS).

The crossover is not there to divide the frequency spectrum alone it also time align (DELAY) the speakers,attenuates the volume to match the drivers,flatten the 2.5k dip in frequency curve etc.


Are the four 12s 16 ohms? from your photos they are connected in parallel to make 8 ohms.


what are the model number of the 8,12 and 18 drivers?
Post some photos of the Eminence OEM tags numbers I will see what info I can get on them.

Jorre Pulle Their is a guy on ebay seller name utdj that has the Oxmoor Sonics Associates IMAX DEQ-1 High Resolution Programmable EQ with controller.


Joseph

[Woofer]

Thanks heaps for that, Joseph.
I hope others here find your input helpful.

The IMAX's have since moved on.
I don't have access to them any more, so what there is, is what there is….

Cheers all.

[Joseph]

Hi

Woofer you got rid of the imax boxes they are outstanding boxes
Just wondering if you got the model number of the 8 inch midrange driver even if its OEM numbers
plus the 12s and 18s

Joseph

[Woofer]

Hi

Woofer you got rid of the imax boxes they are outstanding boxes
Just wondering if you got the model number of the 8 inch midrange driver even if its OEM numbers
plus the 12s and 18s

Joseph

Yes, I'm so sorry Joseph, but they were installed into a studio, and it's just not practical to get access to them any more.
…. but maybe, if someone else is monitoring this thread, they may be able to help.

Read back through this thread, and maybe you could PM one of the others that have them and post your findings here if you could.

Sincerely,
George. (Woofer)

[Joseph]

In the book Electroacoustic Devices Microphone and Loudspeakers by Glen Ballou
About 80 pages are written by Jay Mitchel designer of the Imax enclosure
Lots of information about drivers and enclosures plus some math,loudspeaker performance
Systems and loudspeaker Testing and measurement.

Joseph

[Woofer]

Most excellent bit of info Joseph.

For those that can afford it, then they are available online via the 'bay, or Amazon.
For those that can't, try your local library. They may have a copy.

Cheers lots to all…..

UPDATE: here's a link to an online pdf d/l:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=16&ved=0CFkQFjAFOAo&url=http%3A%2F%2Fgege2061.homecomputing.fr%2Ffetch .php%3Fdata%3D219%26type%3Dpdf%26id%3D234&ei=lTZAU8j7C8OVlQXb-oHwCg&usg=AFQjCNEBsoKHJIqiAVEiBIPySIyES56-sw&bvm=bv.64125504,d.dGI&cad=rjt

[TW14MB]

Hello, I was at a local IMAX and thought the system sounded good, so I got some information from the local technical eng. I recently found this thread so thought I would share. He gave me a printout with this info, it does look like an overview sheet made by Sonics.

Much if this is known already, that the system is "Proportional Point Source" or "PPS" by Sonics.

3-way

x-over points
LF 80hz to 400hz Eminence 12" x4
MF 400hz to 7khz Eminence 8"
HF 7khz to 20khz Tad-2001

Text of interest:

"proprietary horns produce an asymmetric coverage pattern to closely contour with the seating arrangement of the theatre"
"The HF section uses a 1" compression driver produced by TAD (Pioneer)."
"The PPS loudspeakers operate in the frequency range of 70Hz-20kHz. All audio below 70Hz is delivered by the subbass."

I am a little confused by the last statement because of the xover at 80 mentioned in the other specs.

The sheet I have doesn't have OEM part numbers or detail on the subbass.

It was fun to talk to the eng. and learn more about the system.

I would also like to say THANKS to Jay Mitchell for making a great sounding system!!

[Woofer]

Thank you TW14MB (http://www.audioheritage.org/vbulletin/member.php?20902-TW14MB) for dropping in and adding your bit.
Every little bit helps to make this probably the most comprehensive informative thread on the subject of IMAX.

;)

[rlsound]

I think the 70hz is a typo, everything previously found points to 80hz, as the point where the mains roll into the subwoofers.

[mortron]

I scored some Sonics 400x amps for a song... and found this thread. The IMAX xo board has been removed and am left with a molex connector that went to the xo module. I can identify the signal wires but wonder what is needed to get these running in balanced operation. Is Jay still participating on these boards? Perhaps someone else can help me. As I understand, they were sourced from Bryston so it'd be nice to get them running. Thanks.