too many amps tripped the circuit breaker?

1500 watts plus 2700 watts = 4200 watts. Divide that by the voltage (120) and you are pulling 35 amps. There isn't a 35 amp single pole breaker that is commercially available to the general public. I will be willing to bet that your "HT room" is fed by either a 15 or 20 amp breaker. By code, any "branch circuit breaker" is only allowed 80 % of it's rated capacity. That means that you are only allowed to have a maximum of 12 amps on a 15 amp breaker, by code. That also means that you are only allowed to have a maximum of 16 amps on a 20 amp breaker, by code.You are pulling WAY too much power for the circuit.
Breakers trip because of ONE reason: HEAT. Now, the breaker's "guts" will be heated one of two ways. Fast ( short ) or slowly ( overload )
You, legally, need to have more than one circuit feeding you "HT room".
Hope this helps. good luck in all you do and may God bless.

It is pretty much agreed that you overloaded the circuit. Therefore, the circuit breaker did exactly what it was designed and manufactured to do. It worked perfectly.

Eagle Watcher probably has the best answer here. You definitely need an additional circuit (or 2) run from your panel to the HT.

The extension cords from other circuits can get you by as a temporary fix. But, they are never approved as permanent wiring. Please fix this properly. It sounds like you have put a lot of effort and bucks into a killer system. Don't let it go up in smoke now.

We all have our own opinions. I am not a fan of Siemens products. You should have a whole home surge protector. I recommend Cutler Hammer / Eaton products. Here is more info: http://www.eaton.com/ecm/groups/public/@pub/@electrical/documents/content/sa00404002e.pdf

Remember the basics of electricity: W=V×A, or in non-electrician terms, Watts = Voltage multiplied by Amperage.

You mentioned a 2700W sub-woofer amplifier. Assuming the standard US 120VAC household wiring, this gives about 22½A for this amplifier alone - at full power. Mind you, that's if the amplifier is working at full power. On the Sunfire page, they have this amp rated at 400W, which is a measly 3⅓A, so at "nominal" power, there's no worry *usually*.

A1: The reason your breaker didn't blow right away is the way audio amplifiers work. They only draw what power they need to make the amplified sound. If you've only got it up half way, *by the book* you'd only draw half of the max power. Up the volume control, you up the required power, but as you know sound isn't a constant. It could have been at a really loud part of whatever you were watching, or an explosion, or something with a broad sound all across the spectrum as opposed to a few frequencies.

A2: You shouldn't have to worry about actually damaging equipment in the case of an overloaded circuit. Normally, you'd just lose power, have to turn everything off, reset the breaker, and continue on but at a lower volume - and thus a lower power requirement.

A3: One remedy is stretch the required load across multiple breakers. With the kind of power I imagine you're working with, you might want to consider running a separate heavy-duty breaker for each amplifier. The "Standard" US household wiring is usually 15A outlets and 15A breakers, unless specified as heavy-duty 20A breakers / outlets. As 20A outlets, this would give each amplifier about 2400W of power to play with before worrying about an overload - which under most cases should have you covered. A temporary fix is to just turn the volume down - and love on your poor cat for a while, or at least until it goes deaf (JK). Yes, this means you can't crank it for now, but you've got the quality equipment you want - now comes another hard part to make sure the equipment will last for a while churning out the sound levels you want to experience.

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EDIT: Run the power across separate breakers / circuits with an extension cord is exactly correct, with two warnings: heat and power. If the cord is too long, it will heat up and will not allow all the power to go to the destination (extension cords do consume a minor amount of power per foot and shed that power off as heat), but on anything less than, say, 50 feet, it shouldn't be a major worry.
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On a side note, you may also consider putting in a household point-of-entry surge and noise arrester (google "Siemens Primax for more information), and when you do have your theater room rewired, ask for "isolated ground" runs through to the breaker - this will greatly decrease noise piggybacking on the power circuit.

CAVEATS GALORE: a lot of *should* and *nominal* and *typically* and such. I can't guarantee anything because I'm not there with you making sure what I imagine is why and how things are. As always when electricity is concerned, safety first and let common sense prevail. If you don't know EXACTLY what you're doing, let someone who does do it, and that way you won't turn into a crispy critter. Electricity isn't a game, it kills dead.

ADDITIONALLY, thanks for the Onkyo, DT, and Sunfire tips! Keep us updated on your long-term fix!

Tripping a breaker is not going to 'blow up' your system.
Your room is on one circuit right?
If it's 20A. it will deliver a maximum of 2400W. for a minute or so before tripping out.
If it's 15A., that number is 1800W.
Now those "Amp.s" you have are rated in 'peak power output', not constant draw,
but Watts, are a still Watts.
You say you have amp.s totaling 4200W. connected.
'Crank' that assemblage, and you WILL trip out that circuit breaker.

BTW. 4200W. of even very inefficiently produced sound in a small enclosed
space does have the potential to seriously and permanently degrade your hearing,
even on short -term exposure.

You were running dangerously close to the limit from the start and any fluctuation in current could have blown the breaker. All you need to do is to plug the sub into an outlet on a separate breaker and you'll be back to where you were before you bought it. Worse comes to worse and you have nowhere to plug in the sub just unplug it and you're ready to go again.
Hope this helps , Good luck.

as long as the system is protected by breakers you should be ok.

The idea of circuit breakers is to stop the current flow before wires in the walls can overheat, melt the insulation and cause a fire. It takes a little time for that to happen and the makers of circuit breakers take that into account. Why? Because there are many situations when the current flow through a household or shop circuit temporarily exceeds the rated amperage. Electric motors typically draw a very high current to get started. That is why most have a heavy capacitor to give them an extra boost to start. If two or more motors on the same circuit happen to start up at the same time, the current draw can easily exceed the rated amperage for a minute. By providing a delay before the breaker trips, manufacturers save users a great deal of inconvenience without compromising safety.

Rockin' your neighborhood?

I'm not sure what a 'sub' is, but if it draws 2700 watts from a 120 volt circuit you will be overloading it. 120 volt circuits are usually 15 amp circuits, and power receptacles are rated for 15 amps. Sometimes you'll see a socket with one of the prongs looks like a "T" on it's side; these are for 20 amp circuits.

1500 watts is 12.5 amps and should not trip a 15 amp breaker. The guy above who said, "1500 watts plus 2700 watts = 4200 watts. Divide that by the voltage (120) and you are pulling 35 amps." is correct. 2700 watts is 22.5 amps, which will trip the breaker by itself. But like I said, I don't know what a 'sub' is. If it's an amplifier with 2700 watts output and is made for 120 volt operation it surely does not draw too much current by itself. It should say somewhere on it how much current it requires, either in watts of amps. Add up the amps of everything you have going and if it's less than 15 you should be ok. If it only gives you watts, divide watts by 120 to get amps.

You should run whatever high current part of your system on a circuit by itself. The rest of it can be plugged into another circuit, which may require a extension cord.

Good luck.

Circuit breakers trip for 1 of 3 reasons. First is an uncontrolled flow of current such as can occur when a short circuit or a grounded circuit happens. The uncontrolled flow of electrons will quickly overheat and pop a breaker. Second is an excessive amount of current for an extended period of time. An example would be running 16 or 17 amps of current through a breaker rated for 15 amps. It won't trip immediately but it won"t take long to overheat and pop. Third is old age. Breakers are mechanical devices that wear out over time. As current flows though them when the load is energized, the elements of the breaker heat up and expand. when the load turns off, the elements cool down and contract. Eventually it will begin to lose it's strength and fail. It sounds like your problem was probably a little too much current for the breaker. You can have the breaker upgraded to a larger amperage for a small cost. If you're mechanically inclined, you may be able to do it yourself.