X12 Comp Driver

Are there any cheaper alternatives to the recommended comp driver for the X12. The SD740 comes in at £158 which to me seems a bit pricey. Is it really that much better than other drivers costing £50-£60? Is it worth the extra £100?

I already have a couple of BM-D450 so would these do instead?

What about the horn. Would an alternative rectangular horn be ok. I have a couple of PH3616 horns so could I use them?

Thanks

A 1" driver such as the BM-D450 will not give the required performance in an X12.  It will be limited to a 2kHz or higher crossover and therefore will not integrate cleanly with the 12" drivers.

A 1.4" or 2" driver allows for crossovers down to 1k2 or lower lessening the problems at crossover.  Will be louder too.

Compression drivers may all look the same but like cone drivers, they all sound different.  Take two with similar specs, one may be sweet and smooth, the other may try to remove skin at 100yds!  Generally, they more you pay the better they sound, especially at high levels and the more punishment they'll take.

BM-D450's on the PH3616 will work fine in compact single 12"+1" boxes as I believe you have already? Crossover at about 2kHz.

Firstly one of the reasons for needing a lower crossover frequency in the X12 is due to the distance between the acoustic centres of the drivers, particularly the lower 12" and the HF horn.  In order for the sources to integrate at crossover, the distance between them needs to be minimised in terms of wavelengths at the crossover frequency.  Going by these rules, even 1k2 is too high but definitely better than 2kHz.

If you have a very loud 1" CD then you might be able to get away with using one with a pair of 12" drivers but you will need to mount the horn between the two 12" drivers and the midrange will never be as clear as it would be using a larger format compression driver. You might also end up running it too hard to keep up SPL-wise (danger of blowing HF driver).

if i was to build x12s in the future i would only need one pair, is the 45 by 45 degree horn  flare in robs's design inplace on the basis that you pro hire guys would have multiple units, and that directivity would not be an issue to you.

thanks for that.