How to build a dedicated home theatre

[Prof]

Firstly to clarify, "a dedicated home theatre" means that the room you will be using will only be used for watching movies and perhaps some TV..

A home theatre can range in price from approximately $5000 - $500,000 and more !! Some American home theatres cost over 1 million dollars !!

This tutorial will describe how to build the lower end of the range..

Firstly you will need to find a suitable room..The bigger the better, but it must have four walls and a door..Open rooms connecting other rooms will not be suitable..

The other aspect of a suitable room is whether you need the theatre room acoustically removed from the rest of the house..

This requires an additional construction to the room to isolate it from the other rooms..

I will include briefly what needs to be done, but for the most part I will proceed on the basis that this will not be needed..

There are a variety of building materials that are used to construct rooms in a house..Timber or steel framing with plasterboard walls, or brick or concrete block walls..

Each of them have their own acoustic values..

The stages of the building process...

1. Selecting the room..

2. Acoustically isolating the room..

3. Selecting the wall and ceiling paint or fabric coverings..

4. Choosing the type of floor coverings..

5. Setting up the front of room for screen and speakers..

6. D.I.Y the screen or purchasing a commercially made screen..

7. Adding acoustic panels on the side walls..

8. Adding acoustic panels in the front corners..

9. Adding acoustic panels to the rear of the room..

10. Selecting the front speakers..

11. Selecting the surround speakers..

12. Selecting the subwoofer..

13. Choosing the lighting..

14..Selecting Amplifier/ receiver..and ancillary equipment

15. Selecting Blu-ray player..

16. Programming the whole system..

So as you can see there is a lot to building a dedicated home theatre..But the end result is a very satisfying movie experience.. 

More to follow..

[Prof]

 SURROUND SPEAKERS...

The surround speakers are not quite so important as the fronts..inasmuch that you can use bookshelf type speakers and even a different make than your front speakers..

They only need to be a two way system ( bass / mid and tweeter ) with the bass / mid speaker up to approx. 10" in diam..

The reason for this is that you don't get a lot of full on sound as with the fronts, you get mainly ambient surround sound effects with the occasional sound of a jet plane flying overhead from the back of the room to the front or some such similar thing..

When it comes to mounting your surround speakers, they should be directly opposite the ears from your seating position and with the main driver of the speaker approx. 300mm above your head..

If you have a very wide room then the speakers can be mounted 1800mm above floor level..

These locations are based on a 5.1 system..Other systems like 9.2 and bigger require a different set up..

With a 7.1 or 7.2 system you will have surround speakers on the back wall and side walls..

All surround speakers need to be the same make and model..

They should be mounted at the same height as the side surrounds and spaced within the width of your seats..

[EricL]

Hi @Prof

When I was younger, I totally ignored the fact that the speakers must point towards where you sit so that you get full direct sound. It was only later on when I went to a friend's home theatre setup that I heard the difference. As soon as I got home I redirected my speakers towards the centre point of my sofa. It was like a totally new experience and the sound came in so clear. 

Eric

[Prof]

Hi Eric,

Yes it's like chalk and cheese!!..I remember my first experience with surround sound..

I was having a demonstration of a system in a Hi-Fi store and they had just placed these tiny surround speakers on stands right next to the side of the sofa.!!

Totally the wrong way to do it..but I was wrapped hearing a sort of surround sound for the first time..😊

[Prof]

THE SUBWOOFER..

Like the main speakers there is a huge range of commercial subwoofers, starting at about $900 to many thousands of dollars..

Again the simple rule is to buy the most expensive that you can afford..

If you have bags of money then it won't be a problem..but like many of us it's a bit daunting to pay that sort of money..

I'm certainly the latter, so my only choice was to build my own..but where do you start and how difficult will it be.?

Well I discovered a website that has a whole range of DIY subwoofers and for a small fee they will actually send you detailed plans on how to build them.!!

I did this many years ago and built my first subwoofer..

Once the timber had been cut to size,( and they tell you what size each piece should be )  it was just a simple matter of building the box and installing the driver..

The end result turned out very well and that subwoofer lasted many years..

My current subwoofer a much more advanced folded horn subwoofer was built from plans from the same website..

The cabinet was quite complex compared to my earlier subwoofer and about three times the size..

The incredible thing about this subwoofer is that it only uses an 8" 600W. driver..and yet it can shake the walls in my theatre.!!

But if you want to feel the bass thump against your chest..then you can also use a 10" driver instead.!

If you're interested in doing something like this..here is the website..https://billfitzmaurice.info/

The other thing with building your own..you will need a separate amplifier to power it..

Plate amplifier are used to power subwoofers and you can buy these online..It just needs to be a 240V. one with approx. 400W. output..

[EricL]

Hi @Prof

What about those custom boxed subwoofers you find in cars? They produce such heavy bass sounds, but I'm not sure if it's good for the home theatre set-up. What are your thoughts on this?

Eric

[Prof]

Hi Eric,

Interesting that you should mention that about car subwoofers!

The speaker driver I'm using in my subwoofer is used in car subwoofers.!!

Car subwoofers are notoriously just thumpers!! They have virtually no musicality..

When you have a subwoofer in a home theatre, you need to hear more than just a thump..thump!!

Even though subwoofers have a limited frequency range, you want them to blend into the rest of the speaker system..

To do this a cabinet and a good design is needed to enable some musicality into the subwoofer..

[Noyade]

Afternoon @Prof and @EricL. 

Apologies for intruding on your thread Prof - but you guys certainly know your Hi-Fi.

I have a question - or two.

I found this receiver (Yamaha) in a garbage bin. I don't normally look inside people's garbage bins on the kerb but I noticed the power cord hanging out.

I'm not familiar with surround sound (5.1?) connections.

I put two speakers on the FRONT outputs and it works fine.

Today I'm trying two more speakers - presently trying on SURROUND - and it works but the sound seem less loud?

Dunno what EXTRA/SP, ZONE2/PRESENCE or SURROUND BACK BI-AMP is/are?

The CENTRE connections are damaged.

Unfortunately no manual in the bin.

Would there be a better spot for the second pair of speakers?

Thanks for looking.

[Prof]

Hi Noyade,

That was quite a find, finding a Yamaha 5.1 receiver in a bin..!!

The 5.1 means 5 speakers ( 3 in the front and 2 on the sidewalls ) plus 1 subwoofer..

What speakers are you using for the fronts and what are the surround speakers.?

The lower level in the surrounds could be caused by a couple of things..

The level produced by the Receiver may not be set correctly..or the surrounds may have a higher impedance than required which will reduce output..

If the surrounds are old speakers, then that could be the problem..

You won't know until you access the inbuilt program to check levels and optimising speakers..

On my Receiver ( a Pioneer 7.2 ) there is a program called MCACC..When accessed it shows all the speaker information and what the levels are..

You can then access a built-in equaliser to adjust each individual frequency..and a lot more.!!

The Yamaha Receiver has similar program ( I can't remember the name something like YPOA ) which also gives you all the info..

Look for the model number, you could do a Google search for the instruction manual..

Also if you can access the equaliser you will need a sound level meter to correctly set all the levels..

I use a Radio Shack sound level meter...Very accurate, very reliable and reasonably priced..I've had mine for over thirty years.!!

EXTRA SP.. means extra speaker..as in monitor speaker..

ZONE2/PRESENCE..This a separate zone or mode..Some people like to setup up two different types of sound so they can switch between the two..

SURROUND BI-AMP..You can't use that unless your surround speakers have two sets of terminals on the back..

I hope this has helped you to know a bit more about the Receiver..

[Noyade]

Thanks Prof.

I have four cheap speakers and want to place them in strategic areas outdoors - just to listen to a local community FM radio station.

Listening to the radio in the backyard whilst working and tinkering.

I installed a cheap Bunnings TV antenna and cabling to improve FM reception.

I got two speakers going nicely - just wasn't sure where to connect the other two.

My old receiver - a Realistic from 1985 had four dedicated spots for speakers.

Additionally I have four speakers already positioned on a small shed with another receiver (Sherwood - dedicated 4 speaker system) inside. There is moderate weather protection with sheet metal from an old gas hot water system.

The Yamaha with a Sony. The Sony isn't connected - which was purchased from a Garbage Tip Store for $5.

I admit it - I have a receiver fetish.

[EricL]

Hi @Noyade

What a golden find in the bin! This is a Yamaha RX-V665 amplifier and I totally agree with @Prof that this is quite a find. It is a 7.1 channel amplifier and is Bluetooth compatible. This is of course on the condition that the Bluetooth module is still in good condition. Because you are not using the bi-amp connectors, I suggest getting one of the black screw posts and transferring it to the missing spot for the centre speaker. 

As for the connection for your speakers, I suggest transferring them to the front post connectors rather than the surround posts. You'll get better sound from those. Now don't be disappointed if they don't produce any sound immediately, at the front of the amplifier there is a button for Zone 2, these may need to be turned off to transfer the sound back to the front set.

Often when these amplifiers start to fail it is because their solder points get old or one of the capacitors gives in. Is it worth having repaired? Only if it is less than $100, but any more than that and I suggest just waiting for the next amp to come along.

Here is the link to the Yamaha manual: RX-V665 

My last tip for you is to look into the remote for this unit. There are some very good clones on ebay and you can get full functionality out of the amplifier. The remotes are very cheap and if the Bluetooth module is still working you can link your phone or other devices to this amp.

Eric