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confused by power ratings!!!

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Bryan Booth:

--- Quote from: Rob Spence on January 25, 2011, 05:42:58 PM ---In general one chooses an amp to properly power a speaker, not the other way around.
Figure out what speakers you need, then see if you have an amp already. If not, you do some trading (sell/buy).

--- End quote ---

so I guess i would need to figure out how much power I would need that sub to push?  In your opinon, taking into account our current set up and the fact that venues vary greatly, how much sub do we need...I am sooo new to this... please be patient w/me:)

Patrick Tracy:

--- Quote from: Bryan Booth on January 25, 2011, 06:59:02 PM ---so I guess i would need to figure out how much power I would need that sub to push?

--- End quote ---

No, choose a speaker that meets your needs in terms of SPL and coverage, then choose an amp to adequately power it. Other things to factor in are size, weight, cost and efficiency.

Rob Spence:

--- Quote from: Bryan Booth on January 25, 2011, 06:59:02 PM ---so I guess i would need to figure out how much power I would need that sub to push?

--- End quote ---
Subs don't push power!

Ok, slowing down here....

Subs consume power. Specs for a sub will talk about how loud they can go (max SPL) and how loud they will be with 1 Watt (sensitivity).
If you have 2 subs next to each other they will be 6dB louder than just one sub (assuming they are getting enough power).

So, as Patrick says, choose a sub (or set of them) that gets loud enough, is the size you need, and is priced within your budget. Then figure out how much power is needed to drive the sub to the levels you need. Since not everyone has to drive their speakers to the max, you may find that your existing amp will do for now until you can afford a larger one.
Also note that the "power" doesn't come without side effects.  If you want or need monster subs running loud, then you will need lots of electricity to make it work.

Bryan Booth:
Right, excuse my layman verbage...Subs consume power.   I guess I was basically just looking for conformation that the way we are running our equipment is optimal for what we have.  At the same time looking for advise, from people more experienced than I as to the next step in expanding our rig.   So, I have taken into consideration that I should find a sub to fit our needs and then fit an amp to that.  That being said, or needs vary greatly as we play very small rooms to outdoor events, so I guess I am looking for a "general purpose" sub. ( I realize that probably sounds ridiculous to you guys).   Knowing what little I do...Subs consume more power than full range speakers, so I am guessing that I would need a sub that should handle more power than my mains.  Mains are 1000w peak, we run them at 700w, so we need a sub that can handle more than 1000w.  Is my train of thought on the right track?

TJ (Tom) Cornish:
Watts are not [necessarily] an indiation of volume.  In other words - a 1000 watt speaker may not be louder than a 500 watt speaker.

When comparing speakers, the best information comes from a frequency plot of the box's output at a certain power level, which can be multiplied by the speakers power capacity to get a guestimate of the speaker's real-world performance.

There are many pitfalls here - this is not a simple problem. Some subs go louder than others, some have flatter frequency responses, some play lower than others.

In addition to this, you don't necessarily want the loudest speaker.  Size and weight are large factors - if the loudest sub weighs 350lbs and is a 4' cube, you're probably going to think twice about putting that in the back of your minivan.

I would start with this question:

"Our usual gig is for [v] number of people in an [indoor/outdoor] environment.  Our transportation is [w], so we have certain size constraints.  Our budget is x, our existing equipment is [y], and our electrical power capacity is [z].  Are there any speakers that could work well within these limits?"

Once you get some feedback, you can revise your criteria and expectations depending on what the real-world choices really are.

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