I’m pretty new at mixing so with more experience I guess I will get things more right eventually… With that said I’ll get to my problem:
The thing is, I can do a mix that sound very balanced and nice when playing it through my studio headphones or through my studio montiors. But whenever I make an audio mixdown/downmix to a wave och mp3 file, then listen to it through my PC-speakers it sounds so very different. Sometimes it sounds very bad when listening to it through my PC-speakers (Logitech), like when the volume keep going up and down and it sounds really awful. I couldn’t hear that “rapid volume fluctuation” at all when listening to the mix through my headphones (Sennheiser HD 203) or through my studio monitors (Yamaha HS7). The problem is that I have to keep guessing how it will sound through my PC-speakers, before I make an Audio mixdown. Lats night I kept changing the mix 17 times and made 17 audio downmixes but I was so fed up with the end result I just couldnt keep going and it just felt like a complete waste of time to spend all those hours. I’m told that my studio monitors are great but I feel like the sound from them dont represent how it will actually sound when playing it through some other (normal) listening sources.
So, I guess my request and suggestion is to implement some new feature in Cubase that will let you emulate how it will sound in your PC-speakers or through headphones when playing the mp3 on your mobile phone or via some other listening sources, like through a car stereo, etc. Many regards fr Robin!
Humm, that’s not something that can really be done. The way the pros deal with this issue is by listening on different devices. But, and this is important, they also have years of listening to material on different devices and have trained themselves to anticipate how the sound will change. This is a skill like any other that takes time to develop. You are not going to have it on your early mixes any more than you can expect to play Chopin when you start piano.
Assuming you do have great speakers, you probably still aren’t really hearing your mix correctly. The speaker placement & room you are listening in colors your sound a bunch. Parallel walls, ceilings & floors create frequency resonances - which causes some pitches to sound louder or softer than they really are. These resonances are different for every room size & shape. When you mix so it sounds good in that room you end up compensating for the room sound. This in turn tends to sound bad elsewhere.
One way to minimize this is to use reference tracks. These are songs that you know were well recorded in the style(s) of music you are mixing. Then you compare how your mix sounds when compared with the reference & try to make them similar. You may find for example that you need to have more low end than sounds best in your room in order to hear the bottom properly in most listening environments.
Learning to develop critical listening skills isn’t a simple task and will take years if not decades to master. You’ll know you’re making progress when stuff you thought sounded great when you mixed it years ago now sounds lacking.
I’d suggest getting a good book or two on mixing (can’t recommend anything since what I have is very dated). Also google is you friend. Here’s a couple to get you going.
Thanks guys for your replies! And I understand that “welcome”! Yes I realize more & more that the World of mixing is a hellish Place somtimes but still a World of wonder If you get it right and it starts to sound really good. I bought about 5 books and now Reading “Mixing Secrets” by Mike Senior. Really good Reading! Like it a lot! Im also crossreferencing with a lot of different listening devices (speakers), etc. Try to develope those “mixing ears” and understand it will take a long time to get it right but I do see some progress… Also thanks for the suggestions of books/links!
Onboard audio sometimes behaves like that. On my laptop, when I play through the speakers, there seems to be a compressorlike algorithm or any kind of autoleveling going on that increases volume on lower level parts etc. Much like broadcast compression The effect is not there when I plug in headphones. There’s no settings panel where I could disable that function. So don’t get worried, your mix might be ok, it’s just that your playback device has some wannabe artificial intelligence built in
Of course it’s true what the other guys say: improving your mixing skills in general is a process that will take its time, there is always room to grow.
And I understand that “welcome”! 
Yes I realize more & more that the World of mixing is a hellish Place somtimes but still a World of wonder If you get it right and it starts to sound really good. I bought about 5 books and now Reading “Mixing Secrets” by Mike Senior. Really good Reading! Like it a lot! 
Also thanks for the suggestions of books/links!
The effect is not there when I plug in headphones. There’s no settings panel where I could disable that function. So don’t get worried, your mix might be ok, it’s just that your playback device has some wannabe artificial intelligence built in