New DIY Mid High (90deg) - AKA PM90

Robin Fredsson

New member
Feb 7, 2022
Has anyone compared RCF ND950 1.4 vs BMS 4594he 8/16ohm on HF950 horn?
After all the reading that I've done on the matter, it seems like the BMS has the sweetest VHF sound in the business but an MF that sounds "good sometimes and wrong sometimes". The RCF seems to have a great sound up until the VHF where it sounds "surprisingly good" for being such a large driver. So, sound quality wise they've got different strengths that add up to a somewhat equal sum as a whole, I'd say. YMMV though, of course.

Sound pressure wise it's no doubt that the BMS would have a clear edge in the HF and VHF, but that's where added output is the least needed. In the MF, where added output is the most needed, the BMS would have an edge but it's unclear by how much, given that the sensitivity of both drivers on this specific horn is not known. The sibling driver of the RCF ND950 (named ND940) is used by RCF themselves in one of their own designs, the NX45, and with a low crossover point of 650hz, which is very similar to the crossover point of the PM90. But, how hard do they push it? I don't know. Let's say that they send 50w to it. The BMS can take 150w continuously with zero risk of bashing the diaphragm against the phase plug. That amounts to a difference of about 4.8db, which undoubtedly is a lot. If the BMS has more sensitivity as well, which it probably does, the gap increases even further.

The question in the end boils down to; How much sound pressure do you need? How much cash do you have? How much processing and how many amps do you have?

If cash, amps and processing are all abundant I'd go straight for the DCX464 or the DCX354 with all active crossovers.
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