Home Theatre Power Requirements

[NeilR]

Gene DellaSala wrote an article and did a video a while back about home theatre power requirements. He mentioned that most people don't think about power when assembling a home theatre. I'm afraid I'm one of those people. I recently upgraded my speakers and electronics and was hoping to add a pair of SVS PB3000 subs but after watching Gene's video on power requirements I don't know whether I have enough wall power to add the two subs. I was hoping someone in the forum could give me some advice.

Gene gave an example in the article of a typical home theatre where he added the wattage of several components then divided by 4 (I don't know why he divided by 4). The result was 525 watts. This was less than the typical 1800 watts you get from a 15 A line so there was enough power for the components.

I have a dedicated 15 A line that all of my components are plugged into. I don't listen very loud, maybe minus 20 on average. I have a processor, three class A/B amplifiers (one 5 channel + two 3 channel amps), a plasma TV a Blue-Ray player and a sub. Anthem states the processor power consumption under a "typical load" is 60 W, the 5 channel amp is 550 W, the 3 channel amps are 350 W x 2, the plasma TV is 200 W, the Blue-Ray player 100 W and the sub 200 W RMS / 750 W (not sure what number to use with the sub but I'll use the 750 W). That totals 2360 W divided by 4 = 590 W. Each SVS PB3000 sub is 800 W continuous with 2500 W peak power. If I remove the old sub's 750 W (I'm going to sell the old sub) and add the SVS sub's 2500 W x 2 to the wattage of the other components and divide by 4, I get 1652 W. That's pretty close to the 1800 W max.

I doubt the SVS subs will ever be drawing 2500 W; I don't listen that loud. The two 3 channel amps only power the two rear surrounds and the four ceiling speakers so likely aren't consuming Anthem's stated 350 W x 2. Could I add the two SVS subs to the 15 A line or am I lacking adequate power?

Thanks for your comments.

Neil

 

[lovinthehd]

I think you're overestimating consumption in your typical use and power consumption ratings are on what basis? I run a lot of stuff (various amps/tv etc) off a single 15A typical outlet, not trying to set spl records, but haven't had any issues. Peaks may or may not be an issue on draw, so if really concerned you could upgrade your circuits to 20A if you don't mind the expense. Personally I'm not going to go that direction.

 

[mtrycrafts]

Welcome to AH.

As stated above, I also run off a 15A breaker. I have a projector that has a 400W lamp, 2 power amps, 260W each per ch. , a receiver that uses only the amp sections and another receiver that is a processor. At idle, not including the projector that draws pretty much a constant 4A, is 4A, a total of 8A. Never an issue when the sub amps, one of the 260W amps, is hitting 200W on some peaks.

I would not worry.

 

[HTfreak2004]

It depends how your outlets are wired. If in parallel you should be fine as most gear will have reserve capacitors to handle peaks. Unless your running bass heavy content steady don’t even worry. The type of wall wiring that will create an issue is series. You can read about the disadvantages of that type of wiring yourself but if your wiring is arranged as a parallel circuit all should be good until you go for rock concert playback

 

[NeilR]

Thanks for the replies.

I'm basing my consumption estimates on the manufacturer's specs for a "typical load". I thought they were high estimates as well but better safe than sorry.

 

[HTfreak2004]

Honestly I’ve found the bass content becomes compressed at high volumes if too many amps are drawing from the same circuit. Something you should be considering is bass management into your assumptions.

By bass managing you draw less overall current on a circuit then if you were sending a full range signal through your multi channel amps.

Subs amps have great power reservoirs that need to be refilled more while playing movies then music since subs are normally asked to play redirected bass as well as the discrete .1 channel information (this combo is more often referred to as double bass)

I’m not stating music isn’t a bass beast at times rather it’s less likely that LFE is part of a music source ie. 2.0 that isn’t a video as well like DVD/Bluray concerts in 5.1 or more channels.

So consider your listening habits and preferences not just some spec on a particular piece of gear. Trying to figure the wattage math or current requirements to support your gear is usually met with frustrations.

Error on the side of overkill when doing a fresh install and used a high current power conditioner like a furnan when your not going to tear out your existing wires so you can have power in reserve.

It may not be a perfect solution but it is at least a useful one!

 

[PENG]

Gene DellaSala wrote an article and did a video a while back about home theatre power requirements. He mentioned that most people don't think about power when assembling a home theatre. I'm afraid I'm one of those people. I recently upgraded my speakers and electronics and was hoping to add a pair of SVS PB3000 subs but after watching Gene's video on power requirements I don't know whether I have enough wall power to add the two subs. I was hoping someone in the forum could give me some advice.

Gene gave an example in the article of a typical home theatre where he added the wattage of several components then divided by 4 (I don't know why he divided by 4). The result was 525 watts. This was less than the typical 1800 watts you get from a 15 A line so there was enough power for the components.

I have a dedicated 15 A line that all of my components are plugged into. I don't listen very loud, maybe minus 20 on average. I have a processor, three class A/B amplifiers (one 5 channel + two 3 channel amps), a plasma TV a Blue-Ray player and a sub. Anthem states the processor power consumption under a "typical load" is 60 W, the 5 channel amp is 550 W, the 3 channel amps are 350 W x 2, the plasma TV is 200 W, the Blue-Ray player 100 W and the sub 200 W RMS / 750 W (not sure what number to use with the sub but I'll use the 750 W). That totals 2360 W divided by 4 = 590 W. Each SVS PB3000 sub is 800 W continuous with 2500 W peak power. If I remove the old sub's 750 W (I'm going to sell the old sub) and add the SVS sub's 2500 W x 2 to the wattage of the other components and divide by 4, I get 1652 W. That's pretty close to the 1800 W max.

I doubt the SVS subs will ever be drawing 2500 W; I don't listen that loud. The two 3 channel amps only power the two rear surrounds and the four ceiling speakers so likely aren't consuming Anthem's stated 350 W x 2. Could I add the two SVS subs to the 15 A line or am I lacking adequate power?

Thanks for your comments.

Neil

Thank you for providing most of the needed information.

Below are my best guessitmate:

MCA525 - Anthem says 550 W typical, that's conservative, even 300 W is conservative.
MCA325 - Anthem says 350 W typical, again that's conservative, even 200 W is conservative.
Plasma TV - 200 W sounds about right.
Processor - 60 W sounds about right.
SVS PB3000 - Rated 800 W continuous so it could reach that high depending on the contents you play and the distance you sit. So who gave you the figure 200 RMX/750 W that makes little sense?
Blu-ray player - 100 W? I don't believe it, even a loaded Oppo 105 specified only 55 W. A regular Sony type specs says 15 W, so I would say 20 W should be plenty.

You can plug everything into a 15 A outlet, 20 A would be better obviously, but it should be a dedicated one. If not, since there could be 6-8 outlets fed by one 15 A circuit, you will have to make sure what else are plugged into the other outlets.

If you want to be more accurate, then you should use an online calculator to find out what your amplifiers consumed based on your required sound pressure level, distance, speaker impedance, sensitivities etc.

https://myhometheater.homestead.com/splcalculator.html

Once you get the answers you need from the calculator, report back and we can then let you know the predicted power consumption figures for you power amps and subwoofers and then you can do the rest of the math.

 

[HTfreak2004]

Real life example is usually best.

Listening to “Get over it” by the eagles DVD Hell Freezes Over in DTS 5.1

My system bass managed at 80 Hz all gains set to “FLAT” running on a series 15 a circuit with 2 of the 10 plugs occupied by the gear and other 8 plugs not in use!

System is calibrated to 85db referenced to “0” on volume gain.

Playback volume -8db from max my system did not trip breaker but did shut off and reset as a result of insufficient current.

As a result of this disappointing experience I modified my two 40 amp circuits to dual double 20a circuits meaning the top plug and bottom plug each are dedicated with there own hot line so each outlet delivers full power and the breaker is a dual 20a for safety code requirements. I have 2 wall plugs meaning 4 outlets dedicated with 20a each!

Now for the test. Back on goes the Get Over It song and not only did I get over it the sound was a totally different experience. This was by far the best improvement I have experienced for only the cost of one extra double 20a breaker.

So what is my setup you may be wondering?

Paradigm Studio 100v3 mains,
CC570v3 centre, 40v2 surrounds,
Sub15,
Processor Anthem AVM20v2
Main Amp Anthem MCA50
DVD-Pioneer Elite 59AVi
Bluray-Sony UBPX700
PConditioner- Ultrapower HDC-150RM
Projector-Epson Powerlite Home Cinema 500

Sub 15- 1700watts RMS 3400 peaks
MCA50 360watts/channel 1800 total into 2 ohms stable!

Studio 100 if run full range which I did when I had no sub for years put a 2.5 ohm load draw on the MCA50@104hz
The studio 100s are not the most efficient speaker compared to one’s like Klipsch but paradigm is my home brand with still 88db sensitivity measured anechoic/91 in room

So spec your amps and speakers wisely! Never underestimate the potential advantages of using dedicated wall outlets with power delivery greater than your gear specs for RMS ratings. Peaks are normally met with power reserve capacitors inside the unit occupying the outlet to prevent your gear placing that peak demand on the incoming AC line!


15a x 120v typical is useful up to 1440 watts(80% draw continuous)

20a x 120v typical is useful up to 1920 watts(80% draw continuous)

If our gear did not have reserve capacitors to provide energy on demand we would all be tripping our breakers. Don’t over think it and don’t not think about it!

 

[NeilR]

Thanks for your replies. I don't have the option of running new lines connected to 20 A breakers so I'll have to make due with the 15 A line I have. The 15 A line is dedicated to the home theatre components; nothing else is plugged into it. From the replies I've received it seems like I can add the 2 SVS subs and not have a problem.

I used the calculator PENG suggested. I divided my speakers into LCR (same distance and sensitivity), left + right surrounds, rear surrounds and ceiling. I attached screen shots of the results.

 

[HTfreak2004]

Keep in mind that your using a calculator and for all purpose sake is going to be conservative compared to your actual in room response.

Normally your system will output hotter than what that calculator predicts by probably 2-4 db per speaker at your listening position. I know my experience proved that!