In terms of perception of discomfort, I was surprised how loud I could listen to music once my system started to go beyond a certain price/quality point, and I noticed a similar thing once I started buying good headphones. I suspect distortion levels therefore have a significant role to play - I haven’t bothered taking any SPL readings, but I find I can push my home system louder in absolute terms than, say, a standard car stereo before I start to find the sound unpleasant. For example, I can play classical (or pre-loudness war pop & rock) CDs through my system with the volume beyond 11 o’clock and it still sounds great.
Or maybe I’m just particularly sensitive to distortion.
I imagine regardless of the Naim amp you’ll find most folks listen around the 8-9 O’Clock mark and bust a move around 10. I’ve rarely gone beyond that myself at least.
Normal speakers have problems playing loud due to thermal compression. Normally a problem with small speakers with low efficiency. It is an evil circle.
On horn/OB speakers I can play as loud as a want. Without any audible distortion.
I play normally around 9 on the Nac72/180/Arro system. Room is 112m3.
I’m not familiar with Android apps. On iPad some apps give wildly different results from others. I tested all the free ones available at the time, and found 3 (from memory) giving similar results to one another, and giving readings consistent with published data (e.g. background noise level in various types of location, also in keeping with my memory of sound levels a some years previously using a proper, calibrated, meter (though memory is notoriously unreliable. Also check if it is reading dB(A), ‘A’ weighting being conventional for this type of use, and check that for peak it is set to fastest response - I don’t know what type of music you were listening to, but a difference of only 4dB between average and peak levels is very small, indicating negligible dynamic range.
I agree these apps are always a bit dodgy. I use to work in industry and 85db is the point you start wearing ear protection. I also used to regularly measure with a proper meter in my job. Empirically 85db is the point you start to wince at the loudness. I’d reached that level the other day hence why I measured it, or maybe I was worried SWMBO would walk on and moan about how loud it was. 552 volume control is still too sensitive to my mind if I can only play it at 7:30 in a room of 60m3
My DSP on Roon needs 2-3dB of headroom so I rounded it up to 6dB (1 bit) and this means I can get the 52 past 9 o’clock and I think it sounds better for doing so.
I have had a 32.5, 252 and the 552 in the same room as the nap300 and bricks in the last 12 months. Both32.5 and 252 tended to play around the 9 o clock mark for the equivalent loudness of the 552 at 7:30. Don’t get me wrong the 552 is clearly the best preamp but volume adjustment has to be done carefully
10 o’clock on the 252/300 for the LP12 and 9 o’clock for digital seems optimum in my system. Although I do crank it up sometimes, for example on the latest Robin Trower album and like to listen at low levels to Joni Mitchel, Christine Collister etc.