Perhaps you have not seriously listened to the mid-fi speakers that are available. I recently purchased some NHT Super One speakers that were dealer demo's because I was looking for an inexpensive set that I could live with while my favorites were being repaired. In the process I have recently listened to Yamaha, Sony, JBL, Polk, Klipsch, Boston Acoustic, and Infinity. I ended up buying the Boston Acoustics but returned them because the sound, while initially promising proved harsh (sizzle? it seemed even worse than that and did not improve despite continuous play for three days) and impossible to listen to for an extended period. (I also bought them because they had binding posts that would accept my banana plugs and not the inexpensive spring clips that most of the other speakers had!) All of these speakers except the Boston's had "boom problems" as you say to varying degrees.
Since my speakers are still in the shop (3 months and I've given up hope), I am currently looking for new speakers. On the B&W speakers there is a tremendous difference as you go up the range. The low end 300 bookshelf size has a very slight boom in the bass, and a few other minor problems that result from compromises at their cost. The 602 S2 had a slight boom in the bass. When I auditioned it there was also quite a bit of port chuffing noise on some material, but this may not be the case with better amplifiction. Both of these speakers were far better than any of the mid-fi speakers that I listened to.
On the higher priced B&W speakers, the CDM1-NT also had a slight boom in the bass and very slight sizzle in the highs (perhaps not broken in yet). The B&W CM2 and CM4 have none of the bass boom problems and acceptable highs, but have problems with a muddy upper midrange on complex material. The Nautilus 805 has the silkyest highs I have heard from a speaker as well as holographic imaging, but still has some boom in the bass. (I prefer the word bloom because it is just a few bass notes that are very slightly overdone.) With the Nautilus 805's I was drawn into the music and wanted to listen longer than I had time for at the moment. I am considering purchasing them, but I must listen to several others in their price range before I make my decision.
I agree with one of the above comments that B&W speakers are very revealing of inadequate front end equipment. I think a high current amplifier that has tight control of the lower octaves (probably not cheap!) would be a good match for the B&W's from the 600 series on up. As for the high notes, I urge you to postpone your judgement until you have heard a Nautilus series speaker (or any speaker with a Nautilus tweeter) that has been properly broken in. This reportedly takes forever (months???) and many dealers do not have a product playing for long enough to do this (for obvious reasons).
Since my speakers are still in the shop (3 months and I've given up hope), I am currently looking for new speakers. On the B&W speakers there is a tremendous difference as you go up the range. The low end 300 bookshelf size has a very slight boom in the bass, and a few other minor problems that result from compromises at their cost. The 602 S2 had a slight boom in the bass. When I auditioned it there was also quite a bit of port chuffing noise on some material, but this may not be the case with better amplifiction. Both of these speakers were far better than any of the mid-fi speakers that I listened to.
On the higher priced B&W speakers, the CDM1-NT also had a slight boom in the bass and very slight sizzle in the highs (perhaps not broken in yet). The B&W CM2 and CM4 have none of the bass boom problems and acceptable highs, but have problems with a muddy upper midrange on complex material. The Nautilus 805 has the silkyest highs I have heard from a speaker as well as holographic imaging, but still has some boom in the bass. (I prefer the word bloom because it is just a few bass notes that are very slightly overdone.) With the Nautilus 805's I was drawn into the music and wanted to listen longer than I had time for at the moment. I am considering purchasing them, but I must listen to several others in their price range before I make my decision.
I agree with one of the above comments that B&W speakers are very revealing of inadequate front end equipment. I think a high current amplifier that has tight control of the lower octaves (probably not cheap!) would be a good match for the B&W's from the 600 series on up. As for the high notes, I urge you to postpone your judgement until you have heard a Nautilus series speaker (or any speaker with a Nautilus tweeter) that has been properly broken in. This reportedly takes forever (months???) and many dealers do not have a product playing for long enough to do this (for obvious reasons).