What actually determines volume power? Is it watts?

Let me third the question: what Speakers?

My Carver amp 1.5t and Acoustic Research AR-9 play very loud . You don't realize how loud until you try to talk to someone else in the room

 In what is becoming too common around here, the OP seems to have disappeared...

My guess is that this amplifier is thinning out at high volumes and can’t keep up with the demands of the music and the speakers. A high current amp of the same wattage would probably sound fuller at high volumes and might scratch the itch. 

@zlone that is is exactly. So what spec do I look at instead of wattage?
 

Its definitely true that many receivers today when pushed moderately hard reveal their engineering shortcomings all too quickly. There are huge differences between manufacturers amplifiers for a given watt rating. Companies are in general not very honest about their amplifier power ratings, so just because the amp is supposed to be 100 w RMS doesn't mean it is under actual use. A large part of the problem is the never ending reach for more channels of amplification in a home theater setting which further exceed the demands of the modest power supplies in every home receiver sold today. Additionally, some amplifiers will struggle to provide enough current for low impedance loads. Many speakers rated at a nominal 8 ohms are really closer to 4 ohm speakers and demand way more current than an honest 8 ohm load would require for the same acoustic output. I know of one speaker that is rated as a 4 ohm speaker that the impedance is actually 3.2 ohms at its lowest point. These low impedance loads put huge current demands on todays multi-channel receivers.

Further, the water gets muddied further by speaker manufacturer ratings for sensitivity because the conditions under which that sensitivity is measured are often not stated or are generous in much the same way amplifier manufacturers ratings are generous. So its very hard to make an accurate assessment of the performance you will get with any given component pairing of speaker and amplifier.

In your own situation, you might well be content with your system with an increase in power for the speakers you own, but you need to understand what their power handling capabilities are. In my own experience, choosing an amplifier that has a power rating of twice what the speakers are rated for is a safe bet. This ensures the amplifier will have approximately 3 db of headroom at the speaker's rated power. Find out what the minimum impedance of your speakers are either thru finding a reviewer that tests for that number or thru the manufacturer. Make sure the amplifier you have chosen will deliver the power you want at that minimum impedance.

I think in all likelihood your receiver is current limited and is not supplying enough current to keep the speakers happy at your chosen listening level. Having a measurement of the kind of levels you listen to will help you determine if you can fix your problem with more power or not. If you are already listening at 110 db levels as measured at 3 feet from one speaker, the odds of more power fixing your problem are much lower than if your chosen average level is 90 db. That 20 db difference is huge in terms of the power required and if consistent 110 db levels are what is necessary you just might not be able to get there with your chosen equipment.

To wrap this up, go to the app store  on your phone and get a sound level meter app...there are a bunch of them available for any kind of phone you might have. You want to choose one that will allow a peak and hold measurement. Make some measurements at your preferred levels, and report back so we can help you decide what steps to take next. Most likely a modest increase in rated power at the load impedance imposed by your speakers will get you where you want to be. A stand alone amplifier driven from the preamp outputs on your receiver will very likely get you to where you want to be. This will relieve the receiver power supply of doing the heavy lifting. Whether to buy monoblocks or stereo amps is another question and the answer to that is largely dictated by economics though I am sure there are those here who would disagree on that. Either way you are going to spend some money...the question is where to spend it. If you really like your current speakers and don't want to make a change there, then amplifier power is the only other remedy for 'not loud enough.' Choose carefully grasshopper. :)