Thanks for all the great advices.
1)Listening at particularly low volume levels - will try with higher volume.
2)Dead tweeters - they're working.
3)Room acoustics - can't really fix it, my room is sort of a U shape room, need to do too much to fix the problem.
4)A mismatch between amplifier output impedance and the speaker's variation of impedance as a function of frequency. Blue circle BC2 class a.
6)Listening off axis or with improper toe-in, as was pointed out - that means by changing the toe-in we can fix the problem? Definitely will try this.
Thanks
1)Listening at particularly low volume levels - will try with higher volume.
2)Dead tweeters - they're working.
3)Room acoustics - can't really fix it, my room is sort of a U shape room, need to do too much to fix the problem.
4)A mismatch between amplifier output impedance and the speaker's variation of impedance as a function of frequency. Blue circle BC2 class a.
6)Listening off axis or with improper toe-in, as was pointed out - that means by changing the toe-in we can fix the problem? Definitely will try this.
Thanks