I have a av home receiver that can power 100 w per channel. I was wondering what range of watts for an sub?

Question

I have a sony dg510, It can push out up to 500watts, what is the highest watts subwoofer I can buy.

Answer 1

You can buy anything you want. When you calibrate your audio system you will adjust the volume of the sub to match your other speakers. However, here are two rules of thumb you can bank on. #1 You can never have too much bass. #2 It isn't really necessary to match a sub-woofer to the rest of the system. It is vital to calibrate your audio system so the various parts are operating at the proper levels.

Since there are no real standards for claiming amplifier output power, and even if there were the different efficiency of various driver choices would make any claims of output power moot, power is not a concern when discussing sub-woofers. A sub-woofer should be loud enough to fill up the Room it is working in, a larger room needing a more powerful sub-woofer. The other important statistic in sub-woofers is the -3db down point or how low it can go.

Like any other audio equipment, sub-woofer frequency response should always be delimited. Plus or minus 3 decibels (+/-3db) is the standard you should look for. In other words the response should be something like 25Hz-200Hz +/-3db. If the plus or minus 3db is not there the response is meaningless. If it is a different number than 3 the response is too peaky to be useful. Whenever you look at any speakers look for the +/-3db. If it is not there the manufacturer can claim anything at all and not be accused of lying.  

A 3db down point of 30Hz is only fair. 25Hz is good. Lower than 25Hz is excellent. Don't forget to look for the +/-3db.

Answer 2

Buy a self-powered subwoofer - not a passive one.

The sub takes a LOT more power than the midrange or the tweeters. This is why they are often self-powered.  This frees up the power from the receiver to handle the 5 other speakers.

And a "500 watt" receiver is limited to how much it can pump out to each speaker. It is probably 100 watts per channel. Since you wire the left/right speakers to the sub - you can likely only use a max of a 200 watt sub.