Has anyone used the 18 sound 12nmb1000 with the b&c dcx464 and the rcf hf950 horn on the pm90? If so I would very much appreciate getting the eq settings for the speaker. I’m suing a powersoft t604 and a t304. Thanks!!
New DIY Mid High (90deg) - AKA PM90
- Thread starter Peter Morris
- Start date
Good morning everyone and best wishes for the new year! One question: has anyone ever tried the version with the RCF MB12n405? Are there any real advantages over the MB12n351s or is the higher power not very influential? Since the difference is a few tens of € per woofer, I wanted to know if it's worth buying the superior model!
thank you all
thank you all
It's been a long time since we looked into alternate drivers for this horn. On one hand, the 405 offers a significant increase in power handling (~2 dB), however one of the critical parameters for how the horn performs in the effective moving mass (Mms). I would suggest simulating the two in Hornresp to see how it performs.
The 405 should work - the response is a bit bumpy and it will require more EQ to get it flat but at full power it would produce about 2 dB more SPL. Other drivers that look a good are Beyma's 12MC700 and Faital Pro 12FH520. I don't think these were available when I started this project.
Knowing that numerous alternatives to the PM90 have been suggested (thanks PM for all your responses) and trialed using many of these suggestions, it struck me that the design could make a rather good HiFi speaker (with accompanying subs) either using the recommended PA drivers (at 'sensible' levels) or alternatively, could be made even more suitable utilising drivers that would not be suitable for high output performance due to low efficiency or other issues. Has anyone on this forum ever considered this alternative use or even attempted a build a version using such drivers?
Having read the thread in its entirety, I would suggest that the best drivers for this design have already been selected, the only real choice remaining being between BMS or B&C coaxials.
I don't know if anyone mentioned to yet but, RCF offers two horns that are interchangeable and have a cutoff frequency of 500Hz. The HF94(90x40) and the HF64(60x40) and I thought they would be the best approach for the DIY since I want the horns to be interchangeable. My only concern is that the HF94 is shallower that the HF950 (135 mm depth on the HF94 vs 210 on the HF950) and thus it would have less sensitivity? Could that be a scenario? The 60 degree version is deeper (180mm) so I'm not concerned about that
Been a long time working on these things for us... But we're getting pretty close now. Trial fit of all pieces is finished. Due to do the first round of glue in our next session - really excited. We have 4 x TH18's (driven by 18SW115) to pair with them. Will post again when the cabinets are glued up, and a final time after the paint.
Curious as to how these curvatures have been implemented by people (how they made them), and also what this kind of implementation is doing for the box sonically; I'm guessing they do something similar to bass traps in a studio?
The way I read this is a sculpted section of dense foam placed in each corner where indicated.
The way I read this is a sculpted section of dense foam placed in each corner where indicated.
Yes, they are intended to be sculpted out of dense foam. Their purpose is to prevent premature horn expansion. and keep the corner smooth. The smaller of the two is probably not needed (I didn't use it in mine). Rather than dense foam, I used PVC and expanding foam in mine, and others have used various wood bending techniques as well. How you fill that corner is up to you; whatever method seems the most manufacturable to you!
