A lot will depend on the source music. The more lower frequency content the more likely you will get clipping or IMD. It is also not just an amp problem...speakers compress music because drivers quickly exceed their linear operating range - this also leads to a lot of distortion which will make the music sound harsh and perceptively very loud - most noticeable and uncomfortable in the mid range and tweeter.
There is no reason that good source music should not be enjoyable (i.e. not sound too loud) at 90 db SPL average levels - this is still far far lower than most live concert levels even for classical.
Trust your ears and not the SPL meter and calculations. If the sound is effortless crystal clear and undistorted then you should be able to play up to about 95 db SPL at the listening position before it may begin to sound uncomfortably loud ( a rock concert can be thoroughly enjoyed at levels above 100 db SPL with the odd dynamics up to 115 db spl).
If it all sounds way to loud at 90 db SPL this is indicative of high amounts distortion somewhere (for starters make sure you have a good source music - well recorded music and not modern compressed pop trash...good high quality source music played at 90 db SPL will vary from less than 70 to 100 db SPL on a Ratshack meter while a terrible pop recording may only vary from 87 to 93 db SPL)
Unless everyone is using the same reference source music (say for example the Sheffield Labs Drum track test CD) then it is hard to say whether there is a system issue or it is just a genre or source music issue.
There is no reason that good source music should not be enjoyable (i.e. not sound too loud) at 90 db SPL average levels - this is still far far lower than most live concert levels even for classical.
Trust your ears and not the SPL meter and calculations. If the sound is effortless crystal clear and undistorted then you should be able to play up to about 95 db SPL at the listening position before it may begin to sound uncomfortably loud ( a rock concert can be thoroughly enjoyed at levels above 100 db SPL with the odd dynamics up to 115 db spl).
If it all sounds way to loud at 90 db SPL this is indicative of high amounts distortion somewhere (for starters make sure you have a good source music - well recorded music and not modern compressed pop trash...good high quality source music played at 90 db SPL will vary from less than 70 to 100 db SPL on a Ratshack meter while a terrible pop recording may only vary from 87 to 93 db SPL)
Unless everyone is using the same reference source music (say for example the Sheffield Labs Drum track test CD) then it is hard to say whether there is a system issue or it is just a genre or source music issue.