It may use professional components, but the execution is way beyond any pro system.
dave
PS: i was looking at that just the other day
i tend to quickly put aside anything that uses lamps and tubes ... 
Dave having you here,
what do you think of subs that are in a box in wich there is a path that comes back to front port ( big one..just a tad smaller than cone area ) tunned to get wavelength to add on at something like 20-30 ??
is that coherent or ?
Then please guys, lets come back to main topic,
i don't want to start an Imax theater, and i am sure that they have alot more constraints than i do for their setup ...
Back to basics ...
no one clearly answered some of my questions yet ..
- Do we look for removing ALL secondary reflections?
- diffuse surrounds or pinpoint ? what do the mixing studio expect us to have ?
What i need is clear and direct requirements
then we can probably discuss about way to achieve those requirements ...
If i make 2 walls of the room non paralell/perpendicular,
will that help alot with the room modes?
cut the corners also ?
Does a real center benefit really ? or is the compromise of a virtual center correct ?
cause logically, you can make a stereo setup sound DEAD mid screen if u want, then a center doesn't provide much more than more cone areas i guess ..
Dave having you here,
what do you think of subs that are in a box in wich there is a path that comes back to front port ( big one..just a tad smaller than cone area ) tunned to get wavelength to add on at something like 20-30 ??
is that coherent or ?
Then please guys, lets come back to main topic,
i don't want to start an Imax theater, and i am sure that they have alot more constraints than i do for their setup ...
Back to basics ...
no one clearly answered some of my questions yet ..
- Do we look for removing ALL secondary reflections?
- diffuse surrounds or pinpoint ? what do the mixing studio expect us to have ?
What i need is clear and direct requirements
then we can probably discuss about way to achieve those requirements ...
If i make 2 walls of the room non paralell/perpendicular,
will that help alot with the room modes?
cut the corners also ?
Does a real center benefit really ? or is the compromise of a virtual center correct ?
cause logically, you can make a stereo setup sound DEAD mid screen if u want, then a center doesn't provide much more than more cone areas i guess ..
JinMTVT said:
No that is not coherent... besides if you are going for Ultimate HT you don't want BR subs...
I don't think so...
The most current standards are pinpoint, diffuse is from the days of Dolby ProLogic -- it helped cover up the flaws in the surround encoding.
yes... if significant
cut the corners also ?
You will get a lot of differeing opinion of this.... i prefer virtual along with proper seating distance (3.5-4.5 screen heights)
dave
First reflections are the important ones, by the second bounce they are very weak.
The mixing suite does expect you to have anything! They mix the films for cinema conditions in small theatrettes, The small theatres are equiped with active crossovers, the same style of speakers found in cinemas, mounted into baffle walls and totally deadened rooms, similar to the IMAX photos above but the wall is continuous from wall to ceiling complete with the black ductliner. Sound screen is then mounted infront within inches.
Surrounds have an academy curve, now called the x curve on them, often provided on the actual speaker box as a switch option to roll off the hi's from 2 K, this helps defuse the effect so that the sound apears to come from all around you, instead of localising to the nearest surround speaker. Yes this is used in dolby digital installs.
JBL the complete cinema speaker reference pages
page 8 discusses the x curve, This manual is the main reference for speaker placement ect
If you want to hear the movies exactly as the filmmakers intended to make them you could try to replicate your room to a mixing suite/ preview theatre, which is as I ve said is what I would personally do. I personally find the results worth replicating. My school work experience at 17 was in the same mixing theatre that had mixed Star Wars (this might explain my obsession)
If you are going with only individual surround speakers not multiple, use the same full range speakers as the stage for the best match.
I guess you will never know what your missing out on then.
Why are you having a speaker custom made?
ok
custom is because i can 🙂
they won't charge me anything more
and i'll have to make a tour of their factory and try and decide what are the best specs for the drivers i'll need..
i guess that we don't get to do that often ...
Ok ..so pinpoint and the mixing will do it's job
non paralell walls will help alot ..what about curved?
About the JBL paper,i've already went through it
but i find that this concerns more for cinema theater than for my home theater ..
about the mixing room, what are their requriements?
is there any papers we can read on that ?
Dave : so using the backwave timed to get a boost at low FS is called BR ? i dind't even know .. 😛
that will not lead to correct sound reproduction or ?
What kind of sub bass system would you do ?
i'll probably go with 4 18" or 6-8 15" and i wanted to make recess in the front walls on each side of the screen to acomodate the enclosures ..
sealed?
dipole ?
One mentionned bipolar arrangement for surrounds....
and i still don't understand why we would use that ?
doesn't bipolar/omnipolar arrangement create alot of early reflection by "diffusing" the sound ?
What would one think of a setup comprised of 2 fronts 2 sides and a rear louspeark all of the exact same design
MTM or just plain MT + the front sub bass stuff .. ??
best quality possible drivers and so on ..
would be pretty simple
would give a good point source like
?
or do i want to use more drivers ...like arrays ?
or maybe a line array for the front drivers
and MTM arrangement for the surrounds?
What is the ULTIMATE? i need to know what exactly are we aiming at !!! 🙂
i love this discussion ..learning from every single posts 🙂
custom is because i can 🙂
they won't charge me anything more
and i'll have to make a tour of their factory and try and decide what are the best specs for the drivers i'll need..
i guess that we don't get to do that often ...
Ok ..so pinpoint and the mixing will do it's job
non paralell walls will help alot ..what about curved?
About the JBL paper,i've already went through it
but i find that this concerns more for cinema theater than for my home theater ..
about the mixing room, what are their requriements?
is there any papers we can read on that ?
Dave : so using the backwave timed to get a boost at low FS is called BR ? i dind't even know .. 😛
that will not lead to correct sound reproduction or ?
What kind of sub bass system would you do ?
i'll probably go with 4 18" or 6-8 15" and i wanted to make recess in the front walls on each side of the screen to acomodate the enclosures ..
sealed?
dipole ?
One mentionned bipolar arrangement for surrounds....
and i still don't understand why we would use that ?
doesn't bipolar/omnipolar arrangement create alot of early reflection by "diffusing" the sound ?
What would one think of a setup comprised of 2 fronts 2 sides and a rear louspeark all of the exact same design
MTM or just plain MT + the front sub bass stuff .. ??
best quality possible drivers and so on ..
would be pretty simple
would give a good point source like
?
or do i want to use more drivers ...like arrays ?
or maybe a line array for the front drivers
and MTM arrangement for the surrounds?
What is the ULTIMATE? i need to know what exactly are we aiming at !!! 🙂
i love this discussion ..learning from every single posts 🙂
curved is great only if its outward ie wall [) (] sound will bounce unpredictably and great results, [( )] is bad as it will focus refections to a point, like a radar dish.
Exactly as a cinema, JBL page tends to be the reference, there are even more detailed pages in their archieve.
I would personally do a sealed enclosure that is absolutely huge which I would flush mount into the solid wall for an amazingly acurite and real sounding bass. Personally I would only use 1 or 2 in this configuration, but the more the better. This is one step beyond than corner loading and reinforces the lowest frequencies. If bass reflex is mounted ito a wall from personal experience it raises the efficiency at the port frequency too much and needs to be EQ ed back to flat.
That was me because I personally like the effect, defused surrounds create an enviroment similar to the cinema and mixing suite. It is not important overall.
I do tend to think that a Centre channel is important, but this is more about what you find important!!!!!!
I would suggest that over time you try some and hear the differences for yourself. Most of what I am on about is My interpritation of the Ultimate home theatre!!! Realistically most advice here is very good, and the differences are subtle, Great sounding speakers in a good thought out acoustic room really is an ultimate experence, get that right whether with 2 channels or 5.1. and enjoy.
JinMTVT said:
Here's a thought: form the front wall with a 30" rubber surround along the bottom and top, and each side wall so it's free to move in and out. Then, attach the wall to 16 pneumatic rams, which are in turn driver by a variable air source controlled by an amplifier! With 12 square METRES of SD, and with response down to ~1Hz the bass would be sublime.🙂
JinMTVT said:
The only reason to use BR is to get maximum bass out of a small box, or from a (relatively) small driver... with the space created by making the room of appropriate dimension you have no problem building a large woofer box (which means you can specify a large Vas to achieve lower Fs and greater efficency), and with as many drivers as you are talking (i'd go with 4-8 15s*) you have no problems moving air. A pair of push-push sealed woofers is what makes sense.
*Your room is smaller tham mine and i figure 4 XBL 15s will be an appropriatly suitable overkill.
dave
I'm sure the advice your getting here is spot on but in case you want to read up another good place for HT building is
http://www.avsforum.com/avs-vb/forumdisplay.php?f=19
Especially take a look at the sticky on the top of the page called
Acoustical Treatments Master Thread
There you will find answers to all your questions regarding first reflections, fiberglass insulation, corner bass traps etc.
a warning though. Its a long thread 🙂
Cheers,
Exipnos
http://www.avsforum.com/avs-vb/forumdisplay.php?f=19
Especially take a look at the sticky on the top of the page called
Acoustical Treatments Master Thread
There you will find answers to all your questions regarding first reflections, fiberglass insulation, corner bass traps etc.
a warning though. Its a long thread 🙂
Cheers,
Exipnos
exipnos said:
I am used to reading on AVS forum thank you
😀
i'll try and check it out later on 🙂
So big *** lots of drivers sealed for sub bass would be good ..ok
i guess that i could use a regular bass software to try and get dimensions of the box and response ..any that permits the use of multiple drivers??
No need for software,
Typically you aim for 4x the total vas for the best results in a sealed box especially if its placed flush into a wall (or as in the imax photos with 1/4 wavelength wings that would be at least 4 ft on each side). Feel free to make the box out of concrete or bricks for the ultimate quality.
P.S love MJL21193 idea for sub bass😀
and enjoyed reading exipnos av forum link, thanks, I got lost in there for several hours😎
Typically you aim for 4x the total vas for the best results in a sealed box especially if its placed flush into a wall (or as in the imax photos with 1/4 wavelength wings that would be at least 4 ft on each side). Feel free to make the box out of concrete or bricks for the ultimate quality.
P.S love MJL21193 idea for sub bass😀
and enjoyed reading exipnos av forum link, thanks, I got lost in there for several hours😎
Cameron Glendin said:
If you are going to put a woofer in a box using that formula you need to take care in choosing the driver Q as the driver parameters approach the box parameters.
dave
who is talking about tiny drivers here ?
though i do not care about size,
i do not think i will get the SPL for the ultimate movie home theater with tiny louspeaker systems 😛
Yes i will use probably 4 18" or 6-8 15" for the sub
that is the easy part ..
what i need to work on now, is what constitute the best possible solution to home theater ...
Dave: of course i don't think that i'll get everything perfect on the first try, and you are right to be thinking about the 2nd run ..but that implies only loudspeakers and equipment , as room will have to do with how i'll have decided to built it ..
so that is what is the most important right now,
as i'll need to complete my house plans within the next 1-2 months at max. ..
So should i shoot for curved or non paralell walls ?
and by how much does it needs to be not paralell tohave any effect? ( i guess that it goes with wavelength again ... )
What other room DESIGNS should i take into consideration ?
as i said the walls will be all of 4-6inches of concrete covered by 2-3" of polyestyrene foam ..
back to loudspeakers ...
if i use line arrays, what are the pros and cons for home theater ?
+ more spl
+ bigger sound source appearance
+ less distortion for same spl
- cost ( not really an issue 🙄 ..we are talking about ULTIMATE .. i won't spend 20 000$ on drivers..
but i won't limit myself for a few 100$.. )
- comb problem
- timing on all the drivers will be impossible to get right because of different seating positions possible
( not centering everything to aim at 1 spot..but rather an area wich makes it impossible to use distance to drivers to time everything correctly )
what else?
Then, to go dipole or not to ?
i very like sound of dipole arrangement , but is it suitable to home theater?
though i do not care about size,
i do not think i will get the SPL for the ultimate movie home theater with tiny louspeaker systems 😛
Yes i will use probably 4 18" or 6-8 15" for the sub
that is the easy part ..
what i need to work on now, is what constitute the best possible solution to home theater ...
Dave: of course i don't think that i'll get everything perfect on the first try, and you are right to be thinking about the 2nd run ..but that implies only loudspeakers and equipment , as room will have to do with how i'll have decided to built it ..
so that is what is the most important right now,
as i'll need to complete my house plans within the next 1-2 months at max. ..
So should i shoot for curved or non paralell walls ?
and by how much does it needs to be not paralell tohave any effect? ( i guess that it goes with wavelength again ... )
What other room DESIGNS should i take into consideration ?
as i said the walls will be all of 4-6inches of concrete covered by 2-3" of polyestyrene foam ..
back to loudspeakers ...
if i use line arrays, what are the pros and cons for home theater ?
+ more spl
+ bigger sound source appearance
+ less distortion for same spl
- cost ( not really an issue 🙄 ..we are talking about ULTIMATE .. i won't spend 20 000$ on drivers..
but i won't limit myself for a few 100$.. )
- comb problem
- timing on all the drivers will be impossible to get right because of different seating positions possible
( not centering everything to aim at 1 spot..but rather an area wich makes it impossible to use distance to drivers to time everything correctly )
what else?
Then, to go dipole or not to ?
i very like sound of dipole arrangement , but is it suitable to home theater?
Duel concentric is an apropriate name for a woofer that has a high frequency compression driver mounted through the middle of its voice coil (horn is where you would expect the dust cap), The advantages include, that both the bass and hi frequency motors are very close, minimising time allignment issues, and that all the sound comes from one place. They tend to be very efficient and extremly loud.
It is different from coaxials commonly found in car stereos, Tannoy call them Duel Concentric, Altec and P.Audio call them Co Axial which I posted links to earlier.
Reference to diapole was based on acoustic treatment, I assume they use reflected sound, I do not know much about them. Movies use many point sourced speakers to create the atmosphere of reflected sound, people often acousticly treat the area behind the speakers. If your diapole speakers work well with reflected sound. I would do a different acoustic treatment.
It is different from coaxials commonly found in car stereos, Tannoy call them Duel Concentric, Altec and P.Audio call them Co Axial which I posted links to earlier.
Reference to diapole was based on acoustic treatment, I assume they use reflected sound, I do not know much about them. Movies use many point sourced speakers to create the atmosphere of reflected sound, people often acousticly treat the area behind the speakers. If your diapole speakers work well with reflected sound. I would do a different acoustic treatment.
This thread really got mine attention.
Especially talk about movie theatre speaker systems.
I have always found myself enjoying music before the feature. Is it because the room treatment, speakers or both I do not know.
Cameron Glendin because you have much knowledge about movie theather's speakers. I would realy like to know what kind of speakers are used as main speakers in lets say 500 seats theatre and smaler 100 seats theatre.
Especially talk about movie theatre speaker systems.
I have always found myself enjoying music before the feature. Is it because the room treatment, speakers or both I do not know.
Cameron Glendin because you have much knowledge about movie theather's speakers. I would realy like to know what kind of speakers are used as main speakers in lets say 500 seats theatre and smaler 100 seats theatre.
Unfortunately I dont know either, Cinemas do not have a standard aproach, consistancy is a big issue. It depends on the chain or supliers and the age of the venue.
Typically The older styles of single screen theatres feature Altec A4 or A7 speakers, These restored sound fantastic, The A4 is bigger than a telephone box, combine horn loaded and bass reflex, crosses over @ 500 hz to a large format horn and usually feature wings.
JBL has dominated since then untill recently when Klipch's now seem to be a popular choice.
THX is the only real standard for acoustic's and speaker systems, but very few cinemas actually feature it. It covers everything from external noise levels, electronic x/overs, reverberance levels, type of speakers, to the use of baffle walls (which are as large as the screen) where the speakers are mounted into, typically 3 thick gyprock layers on a steel frame. THX cinemas don't always have DIGITAL sound though!
Back stage
Typical < 100 seat cinema would feature 3x single 15" 3" voice coiled drivers in a bass reflex enclosures, with a 2" compression driver and a Bi Radial / Tractic Horn and a single 18"
typical < 500 seat cinema is a twin 15" box, with the compression driver and a very large horn, and additional 18" sub bass units.
typically >500 seats tends to be 4x 15", 2 inch horn anp perhaps 8 x 18" subs.
over the last 5 years there has been several 3way active and 4 way active systems making inroads into the Large Showcase cinemas.
klipsch
Next one is a bigish download, history of cinema/ PA sound all the answers.
Lenard education
A shot of Lenard 4 way active horn loaded speaker system before being placed backstage, Chauvel Cinema Sydney, 360 seat cinema
Thank you for your reply.
I have always wanted to know what lies unseen in cinemas. Now i know.
I'm usually in disbelief when people say their HT is better than cinema sound production wise. If u have 5 small MT and a sub in a normal untreated room it certainly is not cinema sound whatever excels the person in question might be using.
If I understood correctly 15'' co axial as main speaker go long way in producing nice performance. If that would not be enough you would have to start thinking 1'' and 2'' horns for upper range and 18'' from horns down.
Oh almost forgot I have something relevant to the subject🙂
About LA was the reason why that kind of system never got its way in cinema world because it does not deliver bass equally vs distance. If LA would be set optimally for center row the first row would get too much bass and the back row would get thin sound???
So if JinMTVT might want to bring some friends to enjoy ultimate home theater LA's are out of the picture?
I have always wanted to know what lies unseen in cinemas. Now i know.
I'm usually in disbelief when people say their HT is better than cinema sound production wise. If u have 5 small MT and a sub in a normal untreated room it certainly is not cinema sound whatever excels the person in question might be using.
If I understood correctly 15'' co axial as main speaker go long way in producing nice performance. If that would not be enough you would have to start thinking 1'' and 2'' horns for upper range and 18'' from horns down.
Oh almost forgot I have something relevant to the subject🙂
About LA was the reason why that kind of system never got its way in cinema world because it does not deliver bass equally vs distance. If LA would be set optimally for center row the first row would get too much bass and the back row would get thin sound???
So if JinMTVT might want to bring some friends to enjoy ultimate home theater LA's are out of the picture?
Please guys lets keep this on HOME THEATER design ..
you guys can argue elsewhere as much as you want to.. 😀
still waiting on input about the use of line arrays
VS pint point MT or MTM configurations for home theater
All of the studios i've seen photos of use Monitor's type of loudspeaker to mix ..wouldn't it be best to try and mimick them ?
or do they use that because of space compromises?
then ..dipole is usable or not on an HT system ?
you guys can argue elsewhere as much as you want to..
😀 still waiting on input about the use of line arrays
VS pint point MT or MTM configurations for home theater
All of the studios i've seen photos of use Monitor's type of loudspeaker to mix ..wouldn't it be best to try and mimick them ?
or do they use that because of space compromises?
then ..dipole is usable or not on an HT system ?
But we should be talking about your room 1st... all the rest is not nearly as important as the room (i have a really nice room so i am spoiled)
dave
dave
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