How are speakers improved?


Lets look at a hypothetical example of a speaker designer. Lets call him Nigel. Now Nigel has made a bookshelf speaker. It uses state of the art drivers and a braced MDF box. The crossover is 4th order linkwitz riley @3khz. All very typical so far. The speaker is almost ruler flat within its operating range. Off axis is even and quite flat. Distortion is within typical limits. 

He listens to it and sends it off to some reviewers. The response he gets is lukewarm. Its neither good or bad. 

The questions are:

1.) What does Nigel need to do to IMPROVE the speaker beyond its existing performance?
2.) What parameters need to be improved in order to elevate the performance to an even higher standard? 

WHAT IS THE SECRET TO PERFECT SOUND THAT HAS ELUDED NIGEL???
kenjit
I don't know who this Nigel character is, but I can say the furniture shakers are a huge hit with the ladies.
kenjit the answer is obvious Nigel needs you to come and tune his speakers for him.
Problem is Nigel can’t hear for beans and has been duped.  Shoot, Nigels speakers have been out of phase with one another for the past 10 years and he didn’t even know it.


Nigel should tie a bose radio around his neck and jump off a bridge.


Back to the music, ta ta for now!
Nigel is employed by a corporation and he is looking to develop a bookshelf speaker to compete with Brand X, only a better sound at the same price. After looking at some driver specs, he sees something interesting: if he fiddles a little here and there; uses this particular driver and reduces the crossover to 2K he can produce that speaker and get the better sound at the price point.

Nigel sends the design documents upstairs. A few days later he gets a call from Engineering saying great job! But... make one small change, if you don’t mind. Increase the crossover frequency above 2.8K.

Nigel is disappointed -- the crux of the design is that lower crossover frequency. Nigel asks why and Engineering informs him that they contacted the driver manufacturer and the verdict was the longer driver excursion at the lower frequency will increase MTBF by over 45%. The accounting department determined that the extra warranty cost involving labor, stock of replacement drivers etc, will lower the ARR to less than 3% over 10 years, so the project isn’t feasible. The price increase to be doable will price it out of the market.

Morale of the story: if it’s not your money then you don’t call the shots.