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Driver matching vs break in period

I installed a new mid range driver for my B&W 803 SII and noticed that the image shifted to the speaker with the older driver. I got out my radio shack SLP meter and found that the new mid range driver was about 2-3 DB lower than the old driver in the other speaker. I ended up reinstalling the old driver and putting the new one back in the box. The question is: Is this a matter of matching drivers, or is a matter of allowing the new driver to break in, or is a bad driver? Any thoughts?
koryodell
shadorne's avatar
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shadorne
7,477 posts
 
That is odd. Normally a 2 or 3 db shift should not move the image. Are you sure it is exactly the same driver - something else may be wrong.

The image is based on the time arrival of the primary sound at the ears - it takes a LOT of volume level difference to overcome this - probably as much as 10 db would be necessary to begin to shift the image. (Haas effect)
bokfudo
58 posts
 
Most reputable manufacturers measure and match drivers (or match output by tweeking crossovers) for either speaker pairs or to match a model's reference (or output level) closely since any miss-match does affect imaging. I also believe that break in can increase a drivers output but may be only by 1 db or so.
hifitime
715 posts
 
Did they have the same part number?Also switch them (Midrange drivers)between channels to see if crossover is ok.
hifitime
715 posts
 
I guess I should have said,try the new driver in the good speaker and see if it still has a big loss. I don't think that kind of loss is normal.Make sure the plus and minus are correct also.That my 2ยข
johnk's avatar
johnk
1,975 posts
 
Might be a crossover problem
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