Polk Audio RTi A5 + Onkyo TX-NR807 is 135w enough?

It depends on the size of your room which you didnt give the dimensions and the acoustics. A 135w should be loud enough for most people but "concert levels" is pretty loud.

No telling how loud that is without a db meter. Get a SPL meter from your local radio shack if you really want to know know loud it is.

The 807 is rated at 135 watts per channel from 20hz-20khz at 0.08% distortion. If it is correct that is pretty good. They generally dont rate receivers for peak power.

At least by purchasing the 807 if you dont feel it is loud enough you can always add an external amp later if necessary.

A seperate 2 channel amp will not only give you louder cleaner power but better dynamics between loud and soft passages.

check out one of the many Emotiva amps. There is bound to be one to suit your needs.
http://emotiva.com/xpa2.shtm

I dont think you will get anywhere near concert levels with those speakers. For floorstanders they have a pretty low sensitivity (90db). And your receiver most likely will not actually put out 135 watts as its stated.

Another thing is if your playing the speakers really loud, especially polks which are bright to begin with, the highs are going to get very harsh as the amp clips.

If you really want speakers to play loud, i would look into a speaker with a higher sensitivity and a separate amp. Just my 2 cents.

Something like the JTR Triple 8's with a Emotiva XPA-2 would give you concert levels. Or if you want something similar to the Polk floorstanders i would look at the Klipsch RF-82's which have a 98 db sensitivity

That's pretty loud for in home for music. Rock music is generally pretty uniform, but dynamic peaks still come into play. If you're running at 105dbs average and a peak comes along, you're definitely gonna clip. However, if you running at 95dbs average, you can go all day long with that AVR. My thoughts on A5s...they don't need an amp. You might like them better with an amp, but it's not necessary.

90db sensitivity is not considered low for floorstanders. 83-85db would be considered low. There are some very efficient speakers like Klipsch that are in the high 90's range but they use horn tweeters than can be very harsh sounding. At least they are for me.

I would concentrate on speakers that you enjoy the sound of first. If you have to add more amplification to your receiver then do so later.

It's not that 90db is low, its just gonna take more power to get to concert levels.

And if your looking for floorstanders under $2000 i think you could do better than the Polks, especially if you bought used.

For the Klipsch, you definitely need to hear them in person before you buy them. They have them at Best buy so it shouldn't be too hard. They use horn tweeters which many find fatiguing. I don't get fatigued however, so it really depends on your ears. Klipsch are fairly common, so there pretty easy to find used at great prices.

And is this for a 2.1 setup? Because if it is, you would be much better off with a cheap receiver and an amp.

If you are looking for "rock concert" levels you will need big amplification and high sensitivity speaker.

I use a small pair ("book shelf" size) of Dyn Contour 1.3 SEs. They are 85-86 db w/M rating. To make these play loud it takes an incredible amount of amplification! To the tune of 200-400 wpc! Double the perceived loudness takes ten timesw the power. A 3dB difference calls for at least twice the power. Do the math here. Your receiver is probably putting out 135 wpc with two channels driven, not 5 or 7.

An auxilliary amp will cost you but only you can decide how much. Krell, Bryston, Emotiva? These only suggestion, you need to do some investigation yourself.