Dynamic mics - why so difficult to reproduce?

[OneRoomStudio]

The sheer number of condenser microphone companies, projects, and clones out there is dizzying, but I'm always struck by how few high quality dynamic mics there are outside of the half-a-dozen big names (i.e. Shure, Sennheiser, Beyerdynamic, ElectroVoice, AudioTechnica, Audix, etc.), and even those companies are generally producing mics that aren't as well liked as their older models. What gives?

It can't be due to lack of profit margin - look at what these mics are going for theses days! Sennheiser MD409, AKG D20, Shure SM5B, Beyerdynamic M380. These mics go for thousands of dollars. Granted, some of them are somewhat complex (AKG dynamics with bass chambers), but many of them are fairly straight-forward driver-style capsules in a basic housing - often without any circuitry or transformers.

What makes these so difficult to reproduce? Why have MD409's become "holy grail" mics? Why are M380's no longer produced (I know some people have tried replicating them with headphone drivers, with mixed results)? Are dynamic capsules much harder to make than a K47? It seems that there are tons of companies out there making speakers and headphone drivers. How different can it be?

I'm completely ignorant in this space, so it's entirely possible that I'm missing some big factor.

 

[Recording Engineer]

It can't be due to lack of profit margin - look at what these mics are going for theses days! Sennheiser MD409, AKG D20, Shure SM5B, Beyerdynamic M380.

I don’t think profit-margin and the supply and demand of those out-of-production mics, in good-working-order, go hand-in-hand at all. Plus, I pretty-much never see anyone excitingly-raving about the purchase a new MD-441U, regardless of many people thinking it’s nearly the perfect dynamic mic. I know how great they are and I never have either! In fact, I’m not sure if I’ve bought a brand new dynamic mic; maybe once or twice, maybe?

 

[soapfoot]

I’d speculate:

Good condenser mic performance is primarily a result of good capsule and good electronics

The capsule is the hard bit, but you can buy it ready-made

In a moving-coil dynamic, aspects like pattern formation more often make intentional, designed-in use of body/housing acoustics

This would mean we’d have to get not only the moving-coil assembly right, but also the construction of any acoustical labyrinth that might exist within the body itself

Not by any means impossible, but probably harder to use “donor bodies” and such

Headbasket acoustics do matter to condensers, of course… but compared to something like an RE-20, it’s less-integral to the function (read: having a mic that works as intended)

Again, just speculating