Speaker Driver Matching

[Cinellipo]

I am planing on purchasing a set (4) of Usher drivers 8948A from PE and am wondering about the importance of driver matching. every driver has a sticker on the magnet showing a scale of numbers between 0.6 to -0.6. One of the numbers is checked on the scale of each driver. I am wondering what it signifies and if each driver should have an exact or similar match. See photo.
Thanks and happy holidays.

 

[Cal Weldon]

Putting my Sherlock hat on I am going to guess the 88 is the nominal sensitivity rating of 88dB and the -0.2 that is marked there is the measured. So that driver is 87.8. If so I don't think you will notice that small of a difference. I would guess that if the driver falls outside of that scale, it is not sold to the public. All assumptions of course.

 

[69stingray]

That would be my guess also. It could also be a delta from some standard freq. response they may do at the factory at the end of the manufacturing line.