Frequency response + or - 1 dB ??

Thanks to all for input.
My question is simple. 
Why is it obviously technically difficult for speaker designers to provide precisely level frequency response. @kenjit. I accept some listeners want to adjust the sound for different recordings. Old fashioned tone controls and modern equalizers provide that. 

@ptss - The simple answer is $$$. Mr. Dunlavy personally HAND TUNED every one of his speakers to achieve this tight tolerance. This tuning took into account the cross-over components AND the drivers in each cabinet. Doing custom tuning is not practical for anything other than a boutique enterprise. Why is it important to have tight tolerances? If you have a speaker with +/- 3db tolerance, you can have a 6db variance between frequencies coming out of your speaker. Is this important for realistic playback? You decide. Also, if speakers were made with +/- .5 db and music sounded funky in your room, you would know it's not the speakers causing the problem.

I realize the simplest crossover better the sound.  Frequency response starts with flat responce drivers.  Next the cabinet is, especially the front baffle, designed to help naturally flatten drivers.  Finally proper crossover points and the least amount of notch filters possible.  The more crossover to flatten response can certainly make a flat responce sound horrible. Keep it simple, simple, simple.  

As I remember, John Otvos' Waveform speakers actually achieved this via NRC measurements.