Big Size Home Theater Challenges

[liverpool_for_life]

For example Denon x3800h cannot not be choice.

Curious as to why you think this to be the case.

Similarly speakers needs to be capable of handling more than 200 Watts RMS.

Again, why?

Amplifier power needed for a certain level of SPL depends on 3 factors: Maximum SPL required, distance of MLP from speakers and speaker efficiency.

Start with the decision of how far back into the room the MLP is going to be. This, in turn, will dictate how large of a screen is required for the video to be immersive. Work out the lumens necessary for that size image to see what projectors can work. This will help with knowing what's left over for audio.

 

[liverpool_for_life]

Any more suggestions would help.

IMO, you need the assistance of a professional to build this out. I would recommend reaching out to Prateek.

 

[prateekatasniya]

Curious as to why you think this to be the case.



Again, why?

Amplifier power needed for a certain level of SPL depends on 3 factors: Maximum SPL required, distance of MLP from speakers and speaker efficiency.

Start with the decision of how far back into the room the MLP is going to be. This, in turn, will dictate how large of a screen is required for the video to be immersive. Work out the lumens necessary for that size image to see what projectors can work. This will help with knowing what's left over for audio.

yeah!! these are the basics- let us try to apply this.
though your room is 30 feet in length maybe the primary seats would be around 14 feet from the speakers.
why only 14 feet- might be the question - answer is - to get the optimal brightness from your projector and screen.
14 feet distance needs around 165" screen to give an immersive experience, anything above 165 means you will have to shell out a big amount for a high lumens projector.

SPL Calculator

use the above tool to analyse how much power you need.
you need around 30 watts from the amp for a 95dB sensitivity speaker to hit reference levels(98dB) recommended for a HOME THEATER of this size.

make sure the acoustics is done properly - focus on minimal absorption and more of diffusion,

i hope this clears a lot of doubts and helps you go forward with confidence.
NOTE -
1) if the percentage of absorption is high the SPL will reduce significantly.
2) Only speakers with pro audio drivers can give you the kind of impact you are looking for.
3) Only subs with pro audio drivers can produce that clarity and kick needed to drop jaws ( for this room size)
4) home audio brands with pro audio drivers cost a bomb which will cross your budget, this fact leaves you with the option of choosing pro audio brands only.

Regards
Dr. Prateek Atasniya

 

[devdutta]

I have a ht room size 25*15. I am using 7.2.6 configuration with emotiva basx Mr1 avr and two power amps (For fronts and top middle speaker) which provides a quite large amount of room filling power.
Emotiva is very efficient avr .
Channel separation and bass management is superb.

 

[liverpool_for_life]

you need around 30 watts from the amp for a 95dB sensitivity speaker to hit reference levels(98dB) recommended for a HOME THEATER of this size.

Source, please.

I've seen recommendations on the mixing side relative to the size of the room, but none on the playback side. A 0 dBFS input signal should measure 105 dB (115 for LFE) SPL at the MLP to qualify as reference level playback.

 

[prateekatasniya]

Source, please.

I've seen recommendations on the mixing side relative to the size of the room, but none on the playback side. A 0 dBFS input signal should measure 105 dB (115 for LFE) SPL at the MLP to qualify as reference level playback.

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Check the myth number 8.

 

[liverpool_for_life]

Check the myth number 8.

Sorry, no.

CEDIA released a document (RP22) last year that defines performance objectives for private entertainment spaces:

RP22 - Immersive Audio Design Excellence | CEDIA

Redefine how you quantify system performance - Visit CEDIA to learn more and download our RP22 Document: Immersive Audio Design Recommended Practice.

cedia.org

Pretty clear from Section 6 of RP22 that reference level for screen speakers is 105 dB (102 for non-screen speakers and 115 for LFE).

 

[caspian1985]

Sorry, no.

CEDIA released a document (RP22) last year that defines performance objectives for private entertainment spaces:

RP22 - Immersive Audio Design Excellence | CEDIA

Redefine how you quantify system performance - Visit CEDIA to learn more and download our RP22 Document: Immersive Audio Design Recommended Practice.

cedia.org

Pretty clear from Section 6 of RP22 that reference level for screen speakers is 105 dB (102 for non-screen speakers and 115 for LFE).

I’ve read parts of the RP22, and I think it’s ridiculous in places. This is one of them. 105dB is somewhere between a live concert and a jackhammer - there is no way that is ok for reference level, which means continuous hearing. The THX spec defines 105dB as the peak, to be able to handle transients but even the 85dB reference required by the THX spec is loud and would not be the continuos level in a movie

 

[delhite2]

A decent high lumens projector ~2L
A good quality Big screen -180" - 1.3 L
Denon 3800 + DIRAC= 2L
Accessories - like cables, power protection, etc - 1L

A Celto Acoustique 7.2 speaker package.
Including ifix 10 for LCR, ifix 6 for surrounds,2 ifix 17s subwoofers+ amp = 6.5 L
These speakers would not need a power amp because of their high sensitivity.

This is what I would do to get the best bang for my buck.

While I would agree on all counts, a big screen can be easily custom painted for less than 20k, including building costs and paint.
I have been using painted screens for nearly 2 decades, and having experienced, all types of screens I can say that if you take a leap of faith and do the necessary planning you won't be disappointed. Only thing is, it won't be accoustically transparent (if that is a priority).

 

[prateekatasniya]

Sorry, no.

CEDIA released a document (RP22) last year that defines performance objectives for private entertainment spaces:

RP22 - Immersive Audio Design Excellence | CEDIA

Redefine how you quantify system performance - Visit CEDIA to learn more and download our RP22 Document: Immersive Audio Design Recommended Practice.

cedia.org

Pretty clear from Section 6 of RP22 that reference level for screen speakers is 105 dB (102 for non-screen speakers and 115 for LFE).

Yeah.. I'm aware of this cedia document.

The major reason for thx setting 105dB was the ambient noise in theatres ( crowd and ACs) . So to achieve the full dynamic range that level is needed.

However in room - the required levels are lower. ( As you can read in that post)
And when played at 85dB/105dB levels- the audio would be too loud for comfortable and even realistic viewing experience.
One would not want a dialogue to sound shouty.

And another aspect is the money involved.
7dB additional spl requirement means the total system cost could easily double or even triple.

 

[prateekatasniya]

While I would agree on all counts, a big screen can be easily custom painted for less than 20k, including building costs and paint.
I have been using painted screens for nearly 2 decades, and having experienced, all types of screens I can say that if you take a leap of faith and do the necessary planning you won't be disappointed. Only thing is, it won't be accoustically transparent (if that is a priority).

Acoustically transparent is my priority.. gives cleaner look leading to more immersive experience.

And overall i don't see a point saving a few thousands on screen even if it's non AT when the budget is above 5 lakhs.

 

[liverpool_for_life]

[...]there is no way that is ok for reference level, which means continuous hearing.

It doesn't. Reference level capability is 85 dB SPL, with 20 dB of headroom. Reference level playback for movies is simply playing back the movie at the level it was originally mixed. Nothing more, nothing less.

The THX spec defines 105dB as the peak, to be able to handle transients

Correct.

but even the 85dB reference required by the THX spec is loud and would not be the continuos level in a movie

Some films are mixed too hot, though. In those cases, playback volume needs to be dialed down from reference to compensate.

However, for the most part, playback at reference level in a HT boils down largely to capable equipment that's well calibrated and a thoughtfully engineered room that allows for sound to decay quickly enough for reflections to not be overbearing at reference levels.

 

[delhite2]

Acoustically transparent is my priority.. gives cleaner look leading to more immersive experience.

And overall i don't see a point saving a few thousands on screen even if it's non AT when the budget is above 5 lakhs.

It's not a few thousand, considering screen, it's nearly one lakh, and 10% of overall budget.

For me, I have a clean look, speakers are all hidden, left of screen and right of screen and top of screen, hidden behind a black cloth. Can't get any cleaner than this. Screen gives a floating effect... Obstruction less view.
Plus paint enables custom sizes and easy and cheap options to redo, Incase of damages etc.

 

[liverpool_for_life]

However in room - the required levels are lower.

Agree to disagree.

And when played at 85dB/105dB levels- the audio would be too loud for comfortable and even realistic viewing experience.

Not if the system as a whole (speakers, amps, calibration and room treatment) is well-designed to support reference level playback.

7dB additional spl requirement means the total system cost could easily double or even triple.

Agreed. The last 5-10 dB in SPL that's required for reference level capability can be very expensive. HST, the closer you get to reference level capability, the more fun and engaging the HT experience is, IME.

HST, there's been too much focus from the OP (IMO) on SPL. Understandable given the size of the room, but I'd also suggest paying a lot of attention to how wide the seating is going to be (and how many rows) and finding a center channel with the uniformity in off-axis response and enough dispersion in both axes that will work in terms of consistency of sound and coverage for the proposed seating. This is the most critical speaker to get right for HT (subwoofers a close second). Then, identical LCR, if possible. Definitely avoid towers for L and R and a puny center.

Once that's done, zero in on subwoofers. Between 2-4 12 inch subs (Rhythmik would work) would be my recommendation. Lastly, don't skimp on the surrounds and overheads relative to the mains.

It all starts with the room design and layout, though.

 

[prateekatasniya]

It's not a few thousand, considering screen, it's nearly one lakh, and 10% of overall budget.

For me, I have a clean look, speakers are all hidden, left of screen and right of screen and top of screen, hidden behind a black cloth. Can't get any cleaner than this. Screen gives a floating effect... Obstruction less view.
Plus paint enables custom sizes and easy and cheap options to redo, Incase of damages etc.

Times have changed... With a lot of competition screen prices have dropped..
Under 50-60k a 150" screen is available.

 

[delhite2]

Times have changed... With a lot of competition screen prices have dropped..
Under 50-60k a 150" screen is available.

180 inch for 1.30 lakh. (And do note, performance wise painted screens will better a screen worth much more... Much much more).
A painted screen doesn't compare with normal screens but the extreme high end ones.
So for that size a 20k or 30k painted screen, plus when you have a big room, you have the width to accommodate sides besides the screen and hopefully Centre somewhere nice too,where it is invisible and in line of sight.
1 lakh savings are good, and can be used somewhere else in the room.
Plus the added separation of left right center is an advantage too.

 

[arunlouie]

180 inch for 1.30 lakh. (And do note, performance wise painted screens will better a screen worth much more... Much much more).
A painted screen doesn't compare with normal screens but the extreme high end ones.
So for that size a 20k or 30k painted screen, plus when you have a big room, you have the width to accommodate sides besides the screen and hopefully Centre somewhere nice too,where it is invisible and in line of sight.
1 lakh savings are good, and can be used somewhere else in the room.
Plus the added separation of left right center is an advantage too.

Would like to understand more. Again there are more expensive paint for screens alone. What you have used in your most satisfied painted screen output?

Also when you say better than normal screens on what aspect you mention that. Screens comes with different gains and diff grey shades. How thats achieved in paint.


[Just curious to know for next project]

 

[vikas pathak]

180 inch for 1.30 lakh. (And do note, performance wise painted screens will better a screen worth much more... Much much more).
A painted screen doesn't compare with normal screens but the extreme high end ones.
So for that size a 20k or 30k painted screen, plus when you have a big room, you have the width to accommodate sides besides the screen and hopefully Centre somewhere nice too,where it is invisible and in line of sight.
1 lakh savings are good, and can be used somewhere else in the room.
Plus the added separation of left right center is an advantage too.

By painted screen you mean paint on wall/fabric or something else.

 

[ajuvignesh]

Painting a screen is fine but for bigger screen close applications, the centre being at either above or below the screen will only make imaging/phantom centre and the sound from the centre speaker doesn't match. besides, when there is a panning sound the sound won't be smooth across the soundstage. Here is where the Acoustically transparent screen scores.

 

[delhite2]

Would like to understand more. Again there are more expensive paint for screens alone. What you have used in your most satisfied painted screen output?

Also when you say better than normal screens on what aspect you mention that. Screens comes with different gains and diff grey shades. How thats achieved in paint.


[Just curious to know for next project]

By painted screen you mean paint on wall/fabric or something else.

Painted on wall or in my case on hdhmr board isolated from all corners to give a floating effect.
The paint I used is a mixture, of white paint matte , mixed with silver metallic and white pearl(containing mica) and sprayed with a compressor machine with light, Extremely light coats, I have 10-12 coats.
(i don't remember if I added anything more, and the ratios)
This gives it a good gain and contrast as the black levels are controlled.
Perforated (read AT screens) are weaved ultimately, and either you loose some light or sharpness or you loose some sound because of insanely fine weave.
I suggest reading the official silver fire v. 2 thread on AVSFORUM for getting a better handle on painted screens.