Well, now you know why this is the art of recording, and not the absolute this is the way we do it of recording.
You recording gear is going to have much better specs for playback than you bookself system will. Of course it will sound better on it, with nicer speakers.
What is the deal you ask? Well, learn from what you hear playing your stuff back on other systems. Implement these things into how you mix.
Everyone forget that recording gear is designed to sound flat. Home systems have enhancements to the sound. What you should be doing a lot of on your recording system is listening to professionally done recordings on it so that you know what they sound like on your system. Then you will have a sort of standard to work off of.
Hell, most professionally done stuff sounds like crap through my studio monitors. I have Event 20/20 monitors with a Hafler P-3000 power amp, and have everything in the monitor path hooked up with Monster Studio Pro 1000 cable. I AM hearing what it sounds like. As well, my room is realitively flat compared to what a lot of people work in at home. I have sound treatments, etc....
Often to get my mixes to sound right everywhere else, I have to make certain adjustments that don't sound right in the studio. But the benefit of my killer monitor path is that I can hear exactly what I am changing, and with confidence knowing that my monitors are not excessively coloring the signal, or phase shifting frequencies. Also I get extremely good stereo imaging. Those are the reasons why professional studios do not use consumer grade products for monitoring. You just can't accurately hear what it really going on.
Rather than worry about why, start learning to hear different. In time, you will see that your old mixes really didn't sound all that great through your system. They just sounded like what you "thought" they should for your untrained ears. Getting studio ears takes time and practice. Paying attention to little things in the sound and knowing how to adjust them is the art of recording.
Further. Many of the best sounding CD's you have heard probably had a different engineer mix it then who recorded it. Why? Because recording and mixing are two totally different things all together. Each is a specialty. Some engineers excel in both, but often, specializing in one works out better. There is much to learn. Try to get a fresh perspective from others who you trust what they hear. When you have reached the point of hearing fatique while mixing (oh yes, we all get it. Most just don't know how to overcome it!) you start making changes to the mix that are the death of it. Mixing engineers understand this concept and know how to keep themselves from doing so. The trick I always use is after about 5 hours on a mix, if something that sounded great 2 hours ago all of sudden starts annoying me, I take a break, then come back and listen. Usually is sounds great again.
Also, after many hours of mixing, you will start to take out upper midrange stuff in your mix because your ears start hurting from listening to it. The next day, your mix will sound flat, dull, and lifeless because you eq'ed out all of the stuff that gives things their definition. Try to avoid this.
Good luck.
Ed Rei
Echo Star Studio
www.echostarstudio.com