Anyone that can give me an idea.how to evaluate an audio system that has a good amplifying capabilities? Do we focus on gains/power/sound?

 

If an audio system is used to listen to music (not acid rock nor speech) then it should have a wide flat frequency response, very low distortion and be loud enough.

The amplifier power is determined by the sensitivity of your speakers, the distance of the speakers to you and the loudness you want.

I bought my first sound system by listening to systems in a hifi store and selecting the one that cost 1/5th as much as the best sounding one but sounded the same.

Speakers all sound different. Some are made wrong. Select them to sound good with most types of music you like.

 

The German Din standards organisation published the definitive HiFi standard

DIN 45500

http://www.lennartlabs.se/philosophy/greathobby4.htm

The American Society of Motion Picture Engineers also pionered many audio standards.

http://www.aes.org/e-lib/browse.cfm?elib=12172

 

What is the application?

 

The audio industry evaluates products with an instrument as the AudioPrecision. I have 3 in front of me right now at my workplace.

Older models show up at ebay, or if you have access to an audio equipment manufacturer, perhaps they can plot some response graphs, noise, levels, distortion measurements out of your system.

Miguel