yamaha u3 (problem with balance on sound)

Hi everyone.
I have just bought a yamaha u3 1976, and i am delighted with it as i have only been playing for about a year.
However , compaired to my old rud ibach, when i play , the sound below mid c seems really loud and crisp compared to the noteds over mid c , which i have to really hit to get the volume to match the balance.
I do appreciate that the mid lower notes hit as least three strings compared to single, higher up.
Two questions,
Firstly, am i playing to heavily with my left hand and need to play more firmly with my right or could this be a `fault` with the piano?
Secondly, could this be because i am left handed anyway, so that hand would be naturally stronger, and must concentrate on using it more lightly?

My biggest problem here is when i play Yirumas `Wait there`. and `kiss the rain` ,which you can find easily on you tube, has a very strong left hand part, but when i play ,just seems to completely over ride my right hand melody line, and sound very messy.
Any advice and help would be very welcome.
Thanks Neil

It can be you playing too loud, or using the pedal alot while hitting the lower keys, but I doubt that.

I dont know how advanced or how many settings it got, but it could be some kind of settings to controll the lower/upper volume, if it has some sort of splitting ability. ( playing one sound with the lower keys, and another with the higher keys ).

Or it could be that it's old and from 1976? It's over a decade older then me ^_^

I'm no expert on pianos, but can't even very old pianos sound good, if their owners take good care of them? I've seen pianos from the nineteenth century advertised on a website here in Sweden.

Found this video on YouTube of someone playing a Yamaha U3 1977 model and it sounds just great:

https://www.youtube.com/watch?v=9JTVG5FzH5c

One of the related videos shows a man tuning a Yamaha U3. Is it possible your piano needs tuning? It's very convenient being able to tune one's own piano, saves a lot of money.

But this is why I prefer digital pianos; no need for tuning!

You can also post your question on pianoworld.com, always a lot of discussions going on there.

Oh, I believed it was a digital. I should've done a little search. Could it be that the mechanism for the pedlas have gotten stuck. I dont know how it looks inside, but could it be that the soft pedal have gotten stuck? Not the pedal itself, but the thing softening the keys?