What kind of circuits you running for your theater?

[Tiamat]

So, I'll be getting a home built and the GF wholeheartedly agreed the basement is mine to do as I please. It is 28'10" x 18'6" x 8'.

While I can't afford to get a Dennis Erskine designed theater yet, that is the direction I'll be taking it in 5-10 years time.

I want to make sure the electrical aspect is going to be enough.

I've posted on AVS forums, but I figured I'd cross post here to see if you guys have any advice in terms of electricals/wiring you wish was available in the man-cave but are kind of a pain in the ass to put in after the fact.

1. Is 20A circuits sufficient, or should I be going for 30A circuits?
2. Everything on its own circuit or does that lead to shitty ground-loop issues?
3. Prewire RCA/XLR/(what else) at all possible subwoofer locations?
4. What else?

I was thinking of not prewiring for video because I have no clue exactly where the projector might be going within the room and the video standards seem to change every year with HDMI seeming to be heading out. I don't want to wire for HDMI and then suddenly those prewires are useless because something based on CAT/5/6 is being used instead.

As the electrical and prewire type stuff would be rolled into the mortgage, I am not particularly budget constrained so as long as it is comparable to the cost of premium stainless steel appliances, premium laundry room appliances, granite counter top upgrades (this is the unspoken deal I've made with the GF). That leaves anywhere from 1-8k$ for electrical upgrades / prewire in the basement.

I have no clue how much electrical / prewire costs yet. I assume it is within this price range, but I want to "get it right" for "future proofing".

Thanks all!

 

[Exterous]

When you say everything is on it's own circuit, what do you mean? I would have at least one circuit for your equipment (what type/ how many depends on the equipment you need). As for the room itself IIRC code says you should not have more than 12 devices on a single circuit so how many you need there depends on how many lights/outlets you plan on using. Regardless I would probably put lights and outlets on different circuits.

As for video pre-wiring will the basement be drywalled? If so I would strongly recommend figuring out where you are going to want the projector and running at least conduit with a pull string before the drywall goes up. It will make it a lot easier plus you will probably want at least a little bracing for the projector mount

I wouldn't worry too much about HDMI on the way out as I suspect it will several years before we see HDMI completely leave the stage as manufacturers will want to make sure their stuff works with older stuff that still uses HDMI. I mean - how long has the composite video/ S-cable held on for?

Just run HDMI and Cat6 to your projector location and you should be fine

 

[sdifox]

Dual 20A into the room. one for amp, the other for source.

 

[Tiamat]

When you say everything is on it's own circuit, what do you mean? I would have at least one circuit for your equipment (what type/ how many depends on the equipment you need). As for the room itself IIRC code says you should not have more than 12 devices on a single circuit so how many you need there depends on how many lights/outlets you plan on using. Regardless I would probably put lights and outlets on different circuits.

As for video pre-wiring will the basement be drywalled? If so I would strongly recommend figuring out where you are going to want the projector and running at least conduit with a pull string before the drywall goes up. It will make it a lot easier plus you will probably want at least a little bracing for the projector mount

I wouldn't worry too much about HDMI on the way out as I suspect it will several years before we see HDMI completely leave the stage as manufacturers will want to make sure their stuff works with older stuff that still uses HDMI. I mean - how long has the composite video/ S-cable held on for?

Just run HDMI and Cat6 to your projector location and you should be fine

Thanks for the head up on 12 devices on 1 outlet type of "code" idea. I hadn't thought of that.

I will make sure lights/utilities are separate circuit than outlets.

"As for video pre-wiring will the basement be drywalled? If so I would strongly recommend figuring out where you are going to want the projector and running at least conduit with a pull string before the drywall goes up. It will make it a lot easier plus you will probably want at least a little bracing for the projector mount"

That is an awesome idea, i never knew you could do this... I'll keep this in mind. The walls will be drywalled.

If I have 4x 1kw Subwoofers, and 2kw for speakers, that is roughly 6kw peak. Does that mean I probably should have two dedicated 30A circuits? With AC, I don't think it is as simple as 120V * 30A = 3600W since there are phase considerations?

 

[jaha2000]

not phase considerations (your not running 3 phase). ITs the power factor of the device.

 

[bobdole369]

Dual 20A into the room. one for amp, the other for source.

Plenty.

 

[Gibson486]

Does your equipment really that that much? 20A is the equivalent to about 3 HP.

Also, realize that the 30A ckt could cost a little more. You may not just be changing the ckt amperage, but also the wire size.

As for everything on it's own ckt....that is overkill and it will cost alot. Ground loops are more of an issue when you have DC stuff. They happen when you have AC stuff, but it's cheaper and easier to fix, so companies already have all that stuff built into their products (ie, most audio outputs are now isolated).

 

[Apex]

So, I'll be getting a home built and the GF wholeheartedly agreed the basement is mine to do as I please. It is 28'10" x 18'6" x 8'.

While I can't afford to get a Dennis Erskine designed theater yet, that is the direction I'll be taking it in 5-10 years time.

I want to make sure the electrical aspect is going to be enough.

I've posted on AVS forums, but I figured I'd cross post here to see if you guys have any advice in terms of electricals/wiring you wish was available in the man-cave but are kind of a pain in the ass to put in after the fact.

1. Is 20A circuits sufficient, or should I be going for 30A circuits?
2. Everything on its own circuit or does that lead to shitty ground-loop issues?
3. Prewire RCA/XLR/(what else) at all possible subwoofer locations?
4. What else?

I was thinking of not prewiring for video because I have no clue exactly where the projector might be going within the room and the video standards seem to change every year with HDMI seeming to be heading out. I don't want to wire for HDMI and then suddenly those prewires are useless because something based on CAT/5/6 is being used instead.

As the electrical and prewire type stuff would be rolled into the mortgage, I am not particularly budget constrained so as long as it is comparable to the cost of premium stainless steel appliances, premium laundry room appliances, granite counter top upgrades (this is the unspoken deal I've made with the GF). That leaves anywhere from 1-8k$ for electrical upgrades / prewire in the basement.

I have no clue how much electrical / prewire costs yet. I assume it is within this price range, but I want to "get it right" for "future proofing".

Thanks all!

I went with two dedicated 30amp and one dedicated 20amp lines to my HT room. It's probably overkill, but with all of my walls open, I figured, why not.

One 30amp line goes to my Adcom GFA-7807 - 7 channel amp, maxes out at over 600w per channel into 4 ohm (4200w total), all channels driven, given enough juice.

One 30amp line goes into a Crown K2 - bridged mono, 2500w at 4 ohm for SVS B4+ subwoofer.

One 20amp line powers the rest of the electronics including the projector.

No ground loop issues with this setup. In retrospect, I'm glad I did it this way. As long as your main board has enough room, there's really no big cost jump to do so.

While I did prewired the sub location with RCA, since my sub is unpowered, I keep the amp near the electronics. Because of this, it uses speaker cabling between the two (which I also prewired). If you don't know what you're going to use, I'd either prewire a couple of each: RCA, XLR, and a speaker wire, or run smurf tubing (to pull cabling later).

Seriously though, smurf tube everything, pull what you need later.

 

[slashbinslashbash]

Personally, I would start with a bit different view of things. 28x18 is a pretty large room. How many people are you going to want to fit in it? Recliners or dedicated theater seating? How many rows, how far stepped up? The most would probably be 2 steps since it's just an 8' ceiling -- really you should try to move to 10' or 12' if at all possible -- think about the dimensions of the screen, and how far off the floor it will be placed.

For up to, say, 8 people, I'd say you could get by with partitioning the room roughly in half, so the long dimension is 18' and the short dimension is 14'. Putting the seating in two rows of 4, you will have the back row at roughly 16ft and the front row at roughly 12ft which are the right distances for a 100" screen.

All of these considerations will obviously impact your projector placement and other electrical needs, not to mention the necessary wattage to reach the desired sound levels. Also, the partition walls, and possibly the risers as well, should be built as part of the construction and rolled into the mortgage.

So: Start with target number of viewers. That determines your screen size, room dimensions/partitions, and seating/row placement. All of which determine your projector and speaker placement. Which you need to know for your wiring (or smurf tubing).

If you don't want to go through all of this right now, just get the basics run down to the basement, but don't get the basement finished out very expensively, as you will be building new walls and running wires or smurfing through everything when you do decide to sit down and work out exactly how your home theater will be built.

With such a big space available, I would almost be tempted to say that you should build a "room within a room" with an unfinished, narrow walkway all the way around the outside of the actual theater room. Then, when you want to run new cables, it's no big deal: you don't have to dig through anything -- just walk around the outside of the room and poke 'em through the wall. I am not sure what this would do for the acoustics, but from a pure coolness point of view, it appeals to me And it would be a big waste of square footage, but damn, that'd be cool.

 

[RedCOMET]

T,

Do you have a link to your AVS thread. I'm curious about this myself and want to know what the fine folks at AVS suggest in addition to what AT suggest.

 

[Tiamat]

Not partitioning the room I don't think. By placing the seat at 0.62 of the length dimension I have roughly optimized the room mode distribution. There will be 2 main viewers, a single row, up to 5 viewers. The speakers will be placed ~12' from the front wall to optimize their placement via the Golden Ratio. I'll most likely try to do some more research on electronic projector screens that are acoustically transparent. I also have to look into appropriate throws for the projector, I'm thinking a 120" anamorphic screen. Unfortunately, I cannot change the ceiling height which is a bummer.

I definitely appreciate your advice though. Later on, I might consider a room within a room to allow for maximum sound isolation and further room mode optimization -- but that is getting way ahead of myself as that would require something like a Dennis Erskine design

Personally, I would start with a bit different view of things. 28x18 is a pretty large room. How many people are you going to want to fit in it? Recliners or dedicated theater seating? How many rows, how far stepped up? The most would probably be 2 steps since it's just an 8' ceiling -- really you should try to move to 10' or 12' if at all possible -- think about the dimensions of the screen, and how far off the floor it will be placed.

For up to, say, 8 people, I'd say you could get by with partitioning the room roughly in half, so the long dimension is 18' and the short dimension is 14'. Putting the seating in two rows of 4, you will have the back row at roughly 16ft and the front row at roughly 12ft which are the right distances for a 100" screen.

All of these considerations will obviously impact your projector placement and other electrical needs, not to mention the necessary wattage to reach the desired sound levels. Also, the partition walls, and possibly the risers as well, should be built as part of the construction and rolled into the mortgage.

So: Start with target number of viewers. That determines your screen size, room dimensions/partitions, and seating/row placement. All of which determine your projector and speaker placement. Which you need to know for your wiring (or smurf tubing).

If you don't want to go through all of this right now, just get the basics run down to the basement, but don't get the basement finished out very expensively, as you will be building new walls and running wires or smurfing through everything when you do decide to sit down and work out exactly how your home theater will be built.

With such a big space available, I would almost be tempted to say that you should build a "room within a room" with an unfinished, narrow walkway all the way around the outside of the actual theater room. Then, when you want to run new cables, it's no big deal: you don't have to dig through anything -- just walk around the outside of the room and poke 'em through the wall. I am not sure what this would do for the acoustics, but from a pure coolness point of view, it appeals to me And it would be a big waste of square footage, but damn, that'd be cool.

 

[Tiamat]

T,

Do you have a link to your AVS thread. I'm curious about this myself and want to know what the fine folks at AVS suggest in addition to what AT suggest.

They haven't suggested anything yet, but its the weekend...

here is the link: http://www.avsforum.com/avs-vb/showthread.php?p=18886277#post18886277

 

[Tiamat]

I went with two dedicated 30amp and one dedicated 20amp lines to my HT room. It's probably overkill, but with all of my walls open, I figured, why not.

One 30amp line goes to my Adcom GFA-7807 - 7 channel amp, maxes out at over 600w per channel into 4 ohm (4200w total), all channels driven, given enough juice.

One 30amp line goes into a Crown K2 - bridged mono, 2500w at 4 ohm for SVS B4+ subwoofer.

One 20amp line powers the rest of the electronics including the projector.

No ground loop issues with this setup. In retrospect, I'm glad I did it this way. As long as your main board has enough room, there's really no big cost jump to do so.

While I did prewired the sub location with RCA, since my sub is unpowered, I keep the amp near the electronics. Because of this, it uses speaker cabling between the two (which I also prewired). If you don't know what you're going to use, I'd either prewire a couple of each: RCA, XLR, and a speaker wire, or run smurf tubing (to pull cabling later).

Seriously though, smurf tube everything, pull what you need later.

Thanks for your advice. Is "Smurf tube" the industry standard terminology? That sounds like a great idea. I'll definitely consider 3 dedicated lines, sounds like something I could use.

 

[RedCOMET]

Thanks for your advice. Is "Smurf tube" the industry standard terminology? That sounds like a great idea. I'll definitely consider 3 dedicated lines, sounds like something I could use.

Found this thread on AVS about "smurf tubing." Its got pictures too.
http://www.avsforum.com/avs-vb/showthread.php?t=901909

One company that makes "smurf tubing" is Carlon Conduit. I got the above AVS thread by searching Smurf tube ( or was it "smurf tubing")

Edit:
I lied.. my avs search was for "carlon" and not smurf tube/tubing

 

[Tiamat]

Found this thread on AVS about "smurf tubing." Its got pictures too.
http://www.avsforum.com/avs-vb/showthread.php?t=901909

One company that makes "smurf tubing" is Carlon Conduit. I got the above AVS thread by searching Smurf tube ( or was it "smurf tubing")

Edit:
I lied.. my avs search was for "carlon" and not smurf tube/tubing

Thanks so much for that! Sometimes the search tool of these forums (and AVS) don't quite work right! I appreciate your foot work on this!

 

[RedCOMET]

Thanks so much for that! Sometimes the search tool of these forums (and AVS) don't quite work right! I appreciate your foot work on this!

NP. I find that after while.. i just use google and use as my search "site:blahblah.com <search terms>" works a hell of a lot easier than some of the web forums built in searches.

As for AVS, i find their custom Google Search more than sufficient to finding most stuff.