My Journey of Building a Home Theatre

[vinay]

Killing

Hello Venkatcr,

I am sorry for being aggressive and violent, please do not complain to maneka gandhi or to any animal minister that i am trying to kill the poor birds.

I know you will forgive me and not complain but i am worried what if someone else lodges the protest.

In view to this please delete my post about this and other killings if any. Please confirm.

I am not joking.

V.

 

[venkatcr]

Hey Vinay, take is easy. I was just twisting your words and making a joke trying to lighten the situation. 'Killing two birds with one stone', however it is written is a standard English phrase. No one can accuse you of anything.

Cheers

 

[alsekar]

Friends,
I have following query which i trust you will answer.
This is re room dimensions, or specifically 'golden ratios'.
quote "As it turns out, if you design a listening room with exactly the right dimensions, you can spread out the high and low pressure areas so that anoptimum sound field is obtained. Roy Allison, founder of RA labs and Allison Acoustics, has written extensively on this, and in his paper "The Loudspeaker/Room System" he examines some of the "golden room ratios" developed by researchers L. Louden and L.W. Sepmeyer. These golden room ratios are the result of calculating the modal distributions created by low frequency sound waves, and striving for the most uniform distribution. L.W. Sepmeyer's ratios, in particular, have been highly utilized. Our table illustrates the three famous Sepmeyer room ratios that have formed the basis for hundreds of listening room designs over the last 30 years." unquote
(ref: Home Theater Room Dimension Formulas & Calculator)
The room dimensions may not be always exactly the same as golden room ratios, in which case, you opt for a AVR which has 'room correction system' which senses every speaker and adjusts itself based on the feedback . Now, these kind of systems are quite costly.
On the other hand, have a good AVR which is less costly without 'room correction system', tune the speakers while setting up HT by an expert, and leave it at that.
The third alternative, of course, is to modify the room to golden ratios, this alternative may not be practical all the time.
How important are these golden rations anyway???? (Sepmeyer's ratios H:W:L = 1:1.14:1.39 or 1:1.28:1.54 or1: 1.6: 2.33)
Regards

 

[venkatcr]

The golden ratios are ideal, and if you have time, space, and money, it does make sense to build a room with those dimensions. In addition if you curve the front wall, as well as curve the other corners, you do away with the need for bass trap completely. The only issue is whether our contractors will be able to implement our designs.

Though you are right is saying that a single initial set-up is enough, many people feel that the speakers change their characteristics after a bit if use - what is called burn in. This would need a second set up, and maybe a third one. Having a AVR with calibration software built in helps in this as you can do either a manual or auto calibration yourself whenever you want. The other item you would need is a SPL meter. Ideally you would need a PC with measuring and analysis software, but that is expensive.

Cheers

 

[redd]

Venkatcr,
Once we curve the corners[with brick and cement] can the space behind the curve be left hollow or is it to be filled with sand or concrete.If some one has to curve the L-corner where two walls meet,where should the curve start on one wall and end at another to prevent standing waves.

 

[nshankar]

The golden ratio was also discussed in another HT thread started by John in this forum. John has been quiet for a while.
Audiophiles seem to swear that golden ratio will do wonders for not only the room but also for the rack, cables etc.
And even if golden ratio is used, this does not do away with acoustic treatment for the room.
The bottomline is to ensure that one dimension is not a multiple of the other. Select the loudspeakers suitable for the room size and personal preference, a suitable amp to drive the speakers keeping in mind the sources that will be used. Invest a bit in good quality cables and interconnects, and last but not the least, the acoustic treatment for the room.

 

[venkatcr]

Once we curve the corners[with brick and cement] can the space behind the curve be left hollow or is it to be filled with sand or concrete.If some one has to curve the L-corner where two walls meet,where should the curve start on one wall and end at another to prevent standing waves.

No hollow spaces. Everything should be filled in.

In terms of where to start and end will depend upon the angle of curve you provide. An acute angle can start very nears the corners, while a larger angle will need more lengths for start and end.

Cheers

 

[sqvare]

The golden ratios are ideal, and if you have time, space, and money, it does make sense to build a room with those dimensions. In addition if you curve the front wall, as well as curve the other corners, you do away with the need for bass trap completely. The only issue is whether our contractors will be able to implement our designs.

Practical considerations aside (and strolling past the golden trapagon), would the "perfect" listening room be shaped like a slightly flattened egg? With the outermost convexities conforming to golden-ratio measurements?

 

[venkatcr]

Practical considerations aside (and strolling past the golden trapagon), would the "perfect" listening room be shaped like a slightly flattened egg? With the outermost convexities conforming to golden-ratio measurements?

You would be surprised. Modern editing and recording rooms are shaped like the inside of an extended egg. They are mostly curved. If a straight wall in unavoidable, they are angled in such a way that there are not parallel walls. At least the front half of the room. The area behind the listener/editor can be any shape. That is irrelevant, for the sound. But any case they avoid sharp edges and parallel walls altogether.

Cheers

 

[alsekar]

Hi Friends
I have been kind of busy running around meeting budget targets and what not!
But the desire of making my home theatre has not gone away.
The good news is that i have started, first with the carpentry work of creating a partition to separate the staircase portion from the rest of the room. Will post the pics soon.
The partition is made of 12mm ply separted by 100mm timber framework, the in-between space being filled with 2x 50mm thick glass wool.
Also, the mirror and the side rack will be removed from the left hand side wall.
Will continue to post the developments.
Wish me luck!