I thought this would make for an interesting comparison and discussion about why you don’t want to purchase cabinets that have been “upgraded” without considering what that upgrade might indicate.
Here is what the auction said:
“Up for sale are 4 JBL SR-X 4732 speakers. The 12in drivers in these speakers have been reloaded with high powered Eminence Impero 12a drivers. Each driver will produce 1100 watts with a 2200 watt music program. These 12in drivers have about 10 shows on them,I bought them new. Everything works including the baby cheeks. The speakers have some scrapes and scratches on them do to normal wear and tear. Would be able to deliver or meet someone within 200 miles of Shell Rock IA after the speakers are paid for. I also have some speakon to speakon 4 conductor cables I will throw in with the sale also. 1-50ft cable and 1- 8-10ft cable and (2) two 3 foot jumpers. These are one owner speakers- we bought them new. They cost $1600.00 each when we purchased them. The new Eminence drivers were around $500.00 for each speaker. The JBL drivers we felt were getting a little tired so we reloaded them with the Eminence. Each driver is twice the power of a JBL 2206H and we feel the sound is just as good or better. $2900.00 buys all four!”
Let’s compare a JBL 2206H with an Eminence Impero 12a for starters.
Right off the bat I notice that the JBL 2206H has a sensitivity of 95dB @ 1 watt 1 meter. The Eminence Impero 12a has a sensitivity of 93dB @ 1 watt 1 meter. Since there are (2) 12″ drivers in this cabinet, if you swap out the (2) 2206H drivers for (2) Impero 12a, you’ve just lost 4dB of LF if nothing else changes. If you run these boxes full range due to the cross over being designed around the 2206H, one would need to redesign the crossover with the Impero 12a in mind. Bad start.
Next there is the matter that JBL calls the black terminal + (unlike every other speaker manufacturer I am aware of) so if you swap out the JBL drivers for a different brand and put land the red wire on the + of the new driver (as anyone would logically do if they didn’t pay close attention), now you’re LF is not 180 degrees out of polarity with the rest of the box. Maybe the user was aware of this discrepancy and got that right. Without a measurement rig, how would you verify this yourself?
Lastly, the JBL goes both lower and higher and from the frequency response chart for both speakers, the JBL is much flatter.
If I were in the market for some JBL SR4732X, I’d ask if they still have the original 2206H 12″ speakers. If so, and they all work, maybe the concern that they’re “tired” is unjustified. Then you could sell the Impero 12a drivers for even $150 each and get back to a factory spec speaker cabinet.
FYI – I don’t believe they spent $500 per Impero 12a. I can’t find a price anywhere near that high. $250 seems to be close to street price.