Originally Posted by Erod
Thanks, Bear. I didn't account for the peak aspect of this.
I listen generally at 70-75 dB with 90-95 peaks, but I occasionally get a wild hair to get louder on that 80+ range (As you know, many movies don't play nice and seem to want to jump from 70 dB to 105 dB just because they want to mess with us....lol)
What speakers on this discussion are you saying are and aren't efficient enough to get up there properly?
Well, I don't have a specific recommendation for the ones that you are considering, I'm really not very well versed on in wall offerings. I really just wanted to throw the clean output capability consideration into the ring. One of my personal objectives when I upgrade or make a change in my system is to make sure that it will play as loud or louder than I would ever want to listen with clean, accurate sound free from excess distortion, compression, limiting, clipping, etc. It's why I am in the process of upgrading my speakers as well.
I think sensitivity of whichever speaker being considered can be used to calculate whether or not you will get the clean output capability you need. Also, I believe many speakers will show substantial distortion and compression long before the maximum rated power is put into them. So some overkill is helpful. I mean, do I really think my 6.5" Hsu bookshelf speakers will handle 250 watts crossed over at 80 Hz without distorting and compressing significantly? Definitely not. I don't want to rely on them handling 250 watts, or even 150, in order to reach the playback levels I want. No way it will be clean.
I like to work backwards from reference level or whatever you feel your maximum peak playback level might be, or might ever be.
So we start with reference level which requires 105 dB peaks from each speaker LCR. Move backwards to the max volume you think you might want to ever watch. Speaker efficiency/sensitivity is rated at 1m distance with 1 watt or 2.83 volts(which could be more than 1 watt if not 8 ohms).
For every doubling of distance, you lose 6 dB. So for example, if you are 4 meters(12 feet) from the LCR, the SPL drops 12 dB. So a 90 dB speaker at 1m is 78 dB at 4 meters, since you have doubled distance twice from 1m.(1 to 2, 2 to 4).
You can adjust this to your specific situation. Now lets add power to get our SPL up where we need it to achieve the desired playback level. Double power to add 3 dB. So to get the 90 dB speaker back up from 78 to 90 dB, we have to double power 4x, which is 16 watts. In this example, 15 below reference(90 dB) isn't too hard to achieve. For reference level, we need to double power another 5 times. 512 watts. At what power level do you think most speakers will start distorting, compressing, pushing the limits of our amps, etc.
We can make matters much worse than this by increasing our listening distance or using speakers lower than 90 dB efficient.
Anyhow, these generalizations can be used to calculate anyones specific needs.
Start with speaker sensitivity.
-6 dB for every doubling of distance.
Double power for every 3 dB gain. We have to also assume our speakers remain, clean, free of distortion and compression and that our amp can supply the power.
My system will run you out of the room by -10 MV. Not because its too loud, but because it sounds
uncomfortably loud by this level. I've been in the theater of
and I could watch movies in his room comfortably all day at reference level.
I don't want my listening level dictated by lack of capability. And I think this happens much more often than people realize.