Howdy, I've been lurking and have a few questions that I couldn't answer by searching (here, or google.)
Background: mechanical engineer, mid 30's, decent grasp on electrical, got really into cheap chifi iems during the pandemic, then started in on basic mods (mmcx conversions) and in the process gathering tools/components, and working on my soldering skills. So now I have a full fledged aliexpress addiction, and I'm sitting here with some drivers and shells in the mail for diy iem projects.
Not asking for anyone to hold my hand, but pointing me in the right direction on the electrical side especially is greatly appreciated. I think I have, or can obtain, a decent handle on the physical/acoustic damping. But I am also smart enough to know what I don't know, about all the other aspects of this type of project.
Anyway, now for the electrical questions, let's say all are general/hypothetical for now.
1) DIY hybrid iem, 1DD and 1BA in parallel, I assume you can use a low pass inductor on the DD without negative consequence to the BA, true or false? Or do I need an RC low pass on the DD instead? I am generally familiar with the BA inductance and saturation, at least enough to know there are issues and trying to low pass a BA with an inductor is a no-no.
2) Using a single capacitor high pass filter on 2 BAs in parallel, any pitfalls?
3) What is everyone using for crossover design? Downloaded Xsim but can't find any of the common BA driver files (FRD / ZMA files)
4) Not strictly electrical, but has anyone used a knowles SR-32453 for super high frequencies? The graph looks good over 10k, but what really struck me was the fairly stable impedance in that area, not a super sharp increase like you see with most other BAs. At face value it looks way better than say a 30095, which is a very common solution...
5) OK so I lied about these being only electrical questions. Thoughts on a 4x RAF or RAB in series with 2 of the dampers closed, 2 open? Would your thoughts change if there was a dip switch with the option to also put them in 2x2 series/parallel configuration?
6) I have a dayton imm6 set up and can make some reasonable looking graphs for iem comparisons, but I know I still have a lot of work to do on measurements.
7) Yes I know it seems like I'm getting in way over my head. I spent some "real money" on a pair of 10mm planar drivers, so between tweaking those and trying to fix some things I don't like about a few cheaper chifi hybrids, I promise I'll take it slow and do some work on the phsyical/acoustic tuning side. I'm also fine with a guess and check method for more complex multi driver stuff, anything to keep me occupied. Who knows, I might get lucky.
Thanks in advance for any input, I have pretty thick skin so as long as there is a shred of helpful information, just let me know what you really think.