I have some old subs(EAW SB600e) using RCF L15P200AK drivers.
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According to him, RCF says that the L15P400 is a good replacement for my drivers.
Can I expect that the L15P400 will work in my subs or should I stock up some recone kits?
From the way you normally post I'd assume you're not the kind of operator that's careless or abusive, so are these failures
only due to the age of the original drivers?
If so, the P400 should get you within about 1dB of the originals, even though it has slightly less excursion.
If you really are trying to push the boxes hard, you might want to look at something with more, rather than less excursion. LF15X401 fits that bill for only about 10% higher cost.
Normal caveats about using basic modelling (especially to predict high power behaviour) notwithstanding, here's a single unit of each in 90l, tuned to 40Hz and run up to their nominal max excursion. Red is P200AKII, Blue is P400 and Yellow X401. Both of the alternate drivers have a slightly different shape to the overall curve, so if the EAW processing is doing a lot of shaping then this might be a very slight issue. Click images for clearer versions if browsers resize them down and reduce clarity)
If you want to avoid risking that, and were willing to go outwith RCF, the BMS 15S330 gives a basic curve that's a bit more similar to the P200AKII and has very slightly more excursion (if calculated the same way as the RCF drivers) resulting in this when driven to that version of max excursion - just compared against the P200AKII this time, RCF still Red, BMS Green.
HTH,
David
Edit - inserted images rather than attaching for better clarity