[sandeepmohan]

Originally Posted by Funda

I will keep the group posed or may be start a thread once my set up is complete.

It will good to have a receiver with Pre Outs for at least 5 channels. This way, if you do end up with a thirsty set of speakers that are power starved, you can add a better quality power amplifier.

[NetfreakBombay]

Originally Posted by DerAlte

No, all channels are on all the time. Channels are not conditionally turned on

By "On" I mean "Not Silent".

My question is about real world usage of channels other than Left/Right/Center. Are they even used concurrently for significant amount of time?

[Funda]

Originally Posted by NetfreakBombay

By "On" I mean "Not Silent".

My question is about real world usage of channels other than Left/Right/Center. Are they even used concurrently for significant amount of time?

Depends on the mode your reciever is on. If you are in Disco mode all the speakers play music all the time. but if you are in Dolby mode or Neo Cinema mode not all of them are on all the time except the central speaker. Rest of them come as and when required specially the surround speakers to create the feel.

try these scenes and you can feel what I mean.
1. Kill Bill the scene where the girl dressed in school uniform attacks with the iron ball
2. When the arrows are fired in the Movie the Hero
3. When you have a helicopter flying close .e.g in Shooter.

I had a link which had 10 best home theatre demo videos. let me dig for it. But you can find many from your own experience.

[DerAlte]

Originally Posted by NetfreakBombay

By "On" I mean "Not Silent". ...

Hmm... OK, "Rest of the channels are turned on occasionally for effects" makes sense with ...

Originally Posted by NetfreakBombay

... real world usage of channels other than Left/Right/Center. Are they even used concurrently for significant amount of time?

Commercial movies and live recordings (even Sports) are done with at least 5 microphones mounted on each camera. ( Not those shot with multiple Canon 5D Mk2 DSLRs! Nothing wrong with them, but they are not relevant here unless sound was recorded separately from at least 5 mics and mixed in the final version). Even some HD channels broadcast 5.1.

You might have based your assumption on how some songs ('item numbers' usually) start blaring from all directions in a movie theater. If you notice carefully, that is just jacking up the signal in all channels by a few dB during final production. Otherwise, even at other times you can hear signal in the other channels (of course, in a good theater only).

[NetfreakBombay]

Originally Posted by Funda

but if you are in Dolby mode or Neo Cinema mode not all of them are on all the time except the central speaker. Rest of them come as and when required specially the surround speakers to create the feel.

That is my point too.

Since most movies will have low SPL in surround channels, inability to supply full power to all 7 channels "concurrently" should not have any impact in real world.

Originally Posted by Funda

1. Kill Bill the scene where the girl dressed in school uniform attacks with the iron ball
2. When the arrows are fired in the Movie the Hero
3. When you have a helicopter flying close .e.g in Shooter.

I think I have some of these scenes in (DTS calibration Blu Ray IIRC). Lemme run a test on these.

Originally Posted by DerAlte

Commercial movies and live recordings (even Sports) are done with at least 5 microphones mounted on each camera.

Yes, thats the curiosity.

Sound will definitely be recorded with 5+ sources. Microphones as well as background score itself would be multi-track….

While preparing 8 / 6 final tracks out of these source tracks, I assume audio will be placed on 3 “primary” tracks (Left/Right/Center).

.2 and surround tracks will be used for “immersion” on specific scenes.

Originally Posted by DerAlte

even at other times you can hear signal in the other channels (of course, in a good theater only).

With audio editing tools, we can see individual tracks right away. Lemme do few runs on Blu Rays that I have.

[Funda]

Here are a few demo videos to show off your home theater and do some checks. The list is nice but am sure this is not an exhaustive list. My personal favorite is kill bill. Its one movie where you can test Audio / Video and almost everything you need to tell its a good system. Again its not the only video.

http://www.cepro.com/slideshow/image/7623/

[::CMS::]

Originally Posted by Funda

I am trying to set up a home theatre area

I think the room size is not 13 x 12.5, if yes it will be tough to do acoustics due to the strong room nodes / modes in a square room. Also, is the ceiling height 10.5', usually in an apartment it will be ~9 - 9.6'. If possible, can you upload a sketch of the room to get a clear idea about the room.

In general, controlling the low freq (<500Hz) should have the highest priority as it will be the toughest part based on the the dimensions of the room. In a small room, before doing the acoustics you should try the possible speaker positioning (enough clearance for the speakers from the walls) and finding the best listening area, start with the 1/3rd or 70:30 rule.

In a room we cannot completly go for either absorbers or diffusers. Both works on the depth of the material along with the density of the absorbant in case of absorbers. Since the low freq will be concentrated along the joints of the room esp the corners, the other surface needs only the treatment for mid/high freqs, a broadband absorber is more effective. But curtains cannot do that, some material with high weave density will reflect these freqs. I suggest a thin curtain material which is acoustically transparent and have 3-4"broadband absorbers behind. Diffusers are a little bit tricky to use and it needs at least 8-10' clearance from your listening position to get the diffusion effective. You can try bookshelf with books arranged in the depth pattern like QRD, an arithmetic pattern created based on the depth, but the effectiveness in a small room is doubtful. In simple terms the best option in a small room is absorbers.

I see a bottleneck in your equipment, your HTPC need to be a decent one with atleast a Dual core for HD content even if you have separate display card. I am not sure which AVR you are having, if it doesnt have the HDMI connectivity with HD Audio decoding (DTS-HD and Dolby True-HD) you need to have the decoding done in the PC, but a decent card is expensive and not good as a dedicated equipment, Instead I suggest you change the AVR so that the PC sends the bit-perfect digital data and AVR decodes it.

I wont recommend a NAS unless you really need all the NAS services. Infact I was also in the boat, but decided to have my 10TB media server directly connected to the main AV and a separate low power media downloader for downloading activities.

Moreover, you need to check the projector mounting distance from the screen wrt your target projection size.

Originally Posted by barathvajan

1. AV receiver (Budget: 50 K max)
2. a Neat sub (Budget 25K max)
3. Floor standing speakers (Budget: 25k max)
4. Surround speakers (Budget 30K max)

I would suggest you review your budget. Get a decent AVR for 50K - 60K. I see you have allocated more for the surround speakers than the mains. You can get wharfadale bi/dipolars for ~14-15K which is more than enough for surrounds. I wont recommend a floorstander for 25K, it will be far better going for a good bookshelf speaker than a FS in this price range. Also a decent sub from SVS/Velodyne/HSU will costs more than your budget allocation. I would suggest you add equipment in stages. For center channel, get the same speaker as the main ones, if possible, if not get a compatible center speaker.

[NetfreakBombay]

Originally Posted by DerAlte

Otherwise, even at other times you can hear signal in the other channels (of course, in a good theater only).

Loaded tracks from one of the movies (Dark Knight). In this movie, center channel has largest amount of SPL, followed by left right.

This picture shows tracks for full 150 minutes. Highlighted few areas where surround channel is nearly silent.



If we zoom to a scene with dialogues + action, this difference is more apparent.



Scenes:

http://www.youtube.com/watch?v=DsBE51pQS14

http://www.youtube.com/watch?v=YBRgUIx9BJ8

Originally Posted by Funda

My personal favorite is kill bill. Its one movie where you can test Audio / Video and almost everything you need to tell its a good system.

Will run tracks from that movie as well if I can get my hands on Blu Ray.

[::CMS::]

Originally Posted by NetfreakBombay

That is my point too.

Since most movies will have low SPL in surround channels, inability to supply full power to all 7 channels "concurrently" should not have any impact in real world.

If the amp designer also thinks the same way, what will you do? Most of the AVRs in the market plays around with the numbers, say 100w or 150w RMS, but never say an important constraint. In most cases these measures are while playing only 2 channels, it will be ~60w when all the channels are driven. Even if the amp gives out the same power as documented, its always better having the amp power slightly more than the speaker's power to have some headroom for the dynamics in the content. The power supply plays a major role here and separate power supplies can perform far better than a single supply.

[DerAlte]

Originally Posted by NetfreakBombay

... This picture shows tracks for full 150 minutes. Highlighted few areas where surround channel is nearly silent. ...

Hmmm... interesting. But, that was summary of one movie, and one swallow doesn't make a summer! Also, "nearly silent" is not the same as "silent", and PSU design cannot be based on content interpretation.

Anyhow, your point (w.r.t. thread topic) is ...? Are you saying that ...
* there should be only 2 or 3 channels in an AVR (the rest being pointless)?
* the sound engineer should increase the volume on the other channels?
* pseudo-surround is as good as genuine multi-channel sound?
* regulation is unimportant?

[navin]

Originally Posted by NetfreakBombay

Is this a limitation in real-world use? I.e. does music really stress all channels?

A typical 100W x 5 channel AVR has a power supply that is capable of 300W. Given that at least 30% of the power delivered by typical Class A-B systems is converted into heat that means of the 300W PS only 210W is really available for audio.

So how do they call it 100W x 5. Well because the transistors in each of these 5 channels are capable of delivering 100W each (7A per push pull pair) and the PS can deliver 100W (in fact it can deliver 210W)!!!

Now given that the PS is only capable of 210W at low and mid levels most AVRs don't feel strain but push them a bit and most common AVRs fall apart. There are some that are very capable like the Denon 4311 (very old model).

Originally Posted by akshay1234

For the receiver thinking of the Denon AVR-X2000, and for the front and centre speakers planning on Wharfedale Diamond 10.7 series, while the sub will again be a 12" Wharfedale and will the surround in-ceiling speakers.

Wharfedales gave us satisfactory sound at a good price.

Yes the Whafdales will do well with the Denon X2000. Another brand I would look at with this AVR is the Mordant Short Mezzos.

Originally Posted by Funda

Awesome thread. this guy has done similar arrangement to what I have in mind.

Thanks. I'll take that as a compliment.

[NetfreakBombay]

Originally Posted by DerAlte

Hmmm... interesting. But, that was summary of one movie, and one swallow doesn't make a summer! Also, "nearly silent" is not the same as "silent", and PSU design cannot be based on content interpretation.

This is the pattern that I have seen in ~30 BR discs that I have. I posted just one to highlighet it visually.

Average loudness for surround channels is ~20Db lower than front channels. (which coincidently is also a accessibility requirement for Software like Video Games)

Originally Posted by DerAlte

Anyhow, your point (w.r.t. thread topic) is ...? Are you saying that ...
* there should be only 2 or 3 channels in an AVR (the rest being pointless)?
* the sound engineer should increase the volume on the other channels?
* pseudo-surround is as good as genuine multi-channel sound?
* regulation is unimportant?

This was starting point for the discussion.

Originally Posted by NetfreakBombay

Is this a limitation in real-world use? I.e. does music really stress all channels?

From what I have seen, music will be mostly 2 channels and movies will have audio in three. Rest of the channels are turned on occasionally for effects.

Point is:

1. Real world movies and music do not stress ALL channels "concurrently"
2. So if AVR cannot power all channels to full power "concurrently", this should not have any impact, I.e. amplifier should not clip the audio.

[navin]

Originally Posted by NetfreakBombay

1. Real world movies and music do not stress ALL channels "concurrently"
2. So if AVR cannot power all channels to full power "concurrently", this should not have any impact, I.e. amplifier should not clip the audio.

Sure if the AVR is not stressed (like some better ones) then no problem but in my little world I tested the Onkyo 3010 in 7.1 mode with and without a 2 channel amp for the front channels and adding the 2 channel amp for just the front 2 channels made an audible difference.

Maybe I was listening to higher levels (the room is 31' x 12' x 9') but the Onkyo was happier when it was relived of doing duty for the front left and right channels and driving just the centre and 4 rear speakers. The system in question can be seen in the audiocircle link a few posts back.

[::CMS::]

Originally Posted by navin

the Onkyo was happier when it was relived of doing duty for the front left and right channels and driving just the centre and 4 rear speakers.

Yes, it does make a big difference. I am using my old onkyo receivers' amp for powering different channels in my HT (TX SR-606 for center channel and HT-R320 for surround channels) and the front L/R with Quad 909 poweramp.

[NetfreakBombay]

Originally Posted by navin

Maybe I was listening to higher levels (the room is 31' x 12' x 9') but the Onkyo was happier when it was relived of doing duty for the front left and right channels and driving just the centre and 4 rear speakers. The system in question can be seen in the audiocircle link a few posts back.

You have an amazing setup.

I am certain a 210 Watt AVR will be running for cover if paired with your custom speakers. (Just a guess, each of these speakers might be capable of drawing 80 - 150 Watts at moderate loudness, it that in the right ballpark?)

From what I have seen, such AVRs (without discrete PSUs) are capable of working fine with speakers like Wharfdale Diamond 10 or other bookshelf speakers from Polk / JBL etc in 40 - 70k range.

Such speakers are rated for 60 - 100 W each, and not all channels are driven at the same time by audio sources.