Ohma World Microphones

[rodaffleck]

Beautiful looking mics, and exciting to see a company that doesn't just do lip service to diversity and inclusion but fearlessly embraces and integrates it into every facet of the business. Also, huge fan of Bartees Strange and he sounds lovely in that clip.

 

[Scrappersa]

I wouldn't mind getting my hands on a dual diaphragm version of that capsule if they're ever sold privately for DIY.

Does that mesh around the capsule act as a Faraday cage? First time I'm seeing something like that inside of a large diaphragm condenser.

The headbasket area is a bit too tall IMO, but other than that I really love the look, especially now that I know it's not another crappy SDC electret like the crap all over AliExpress and eBay. I've definitely thought off designing my own bodies and using either wood or plastic to prototype, obviously with a metal grille, then maybe conductive tape inside to help shield it. Though these mics are doing almost exactly what I had planned (I would just shorten the headbasket quite a bit). I have no idea what specific capsule it is, but it's very much like what I was considering for my own design (I probably would've gone with a good Chinese edge terminated capsule to keep costs down). Can't wait for a multipattern version. One of the few indie mics I'm actually excited for.

Thanks for the nice comments everybody!

The top area is that height because we designed the ribbon version first and wanted to use the same body/screens for both that and the condenser. Over the years, we've found that this specific ribbon size, shape, and tuning is our favorite sound. It's the same ribbon from the RCA 44 so it's a bit longer- hence the longer top section.

Originally, we used acrylic and wood for prototyping the screens. The material doesn't seem to change the pickup significantly. The wood looked very cool but it's not too durable if you're swapping screens. I've been making new screen designs on one of those cheapo laser cutters. It's a lot of fun experimenting with different shapes and hearing how it changes the sound.

Back when we originally designed the body and screens, me and my good friend, Peter, were going to a makerspace a few times a week to machine parts. The funny thing is that the main reason the mic ended up flat is because the makerspace didn't have a CNC lathe, they only had a CNC Mill. So I figured, well, how can I make a 2x7x1 piece of aluminum both sound and look good.

The toughest part about making a multipattern version at this point is finding a nice switch that fits and isn't noisy, as well as dealing with RF from the wires. Our capsules have metalized mylar on both sides so it wouldn't be too hard to experiment with. Just need to make a capsule with nicely matched sides. If you're interested, DM me and I can play around with a multipattern one for you. @Icantthinkofaname

The capsule is a modified version of the Debenham, Robinson, and Stebbings capsule. We've made a few mechanical changes to it. I wish I had more information about the magazine and authors, but the backplate design was published in an article written in a magazine many years ago. (1960s, 1970s?). It's never been used in a commercial product as far as I know. It's a really unique capsule. I haven't heard a capsule before with this kind of low end and top end combination. We spent a long time listening to different tensions/capacitances until we found this one and fell in love. We felt like it was different enough from the capsules we love but stood next to them in their own way. We call it the 'Debby' for short.

Yes! The circuit is a modified 84 circuit. We've changed the transformer ratio as well as the caps to allow for more of the natural bass from the capsule to pickup. In the original 84, they limited the bass since it would overload the smaller capsule. And yeah! We are lucky that we have a ton of NOS Cinemag transformers from the 90s that we love the sound of. They should last us a long time! Transformer winding is a mystic art I've always wanted to explore.

Happy to answer any other questions about the mic and the design process.

 

[Barry Hufker]

Any worries about body resonances/vibration with switchable parts?

 

[Icantthinkofaname]

The top area is that height because we designed the ribbon version first and wanted to use the same body/screens for both that and the condenser. Over the years, we've found that this specific ribbon size, shape, and tuning is our favorite sound. It's the same ribbon from the RCA 44 so it's a bit longer- hence the longer top section.

I saw a video saying that right after commenting, and I totally get it. I'm a little nitpicky about stuff like that, most people aren't though. I also feel like the modern C414s are a bit too big in tbe headbasket.

Back when we originally designed the body and screens, me and my good friend, Peter, were going to a makerspace a few times a week to machine parts. The funny thing is that the main reason the mic ended up flat is because the makerspace didn't have a CNC lathe, they only had a CNC Mill. So I figured, well, how can I make a 2x7x1 piece of aluminum both sound and look good.

Oh wow, that's a funny coincidence. It's the flat body that interests me the most as I've wanted to try a DIY mic that's easy to position, but definitely need a looot of practice before designing my own. I would've gone with an edge terminated Chinese capsule or a pair of those small diaphragm capsules Kingkorg really likes with the C12ish high end.

I'll definitely let you know if I'm interested in a multipattern one, I have that Shuaiyin C414 copy that needs a better capsule. Pretty sure they stuck the cheapest K67 available in their, which sounds awful, both sibilant and muddy. And I'm sure your capsule would have a lot better off axis response than the Chinese edge terminated capsules with the K67 backplates.

The toughest part about making a multipattern version at this point is finding a nice switch that fits and isn't noisy, as well as dealing with RF from the wires. Our capsules have metalized mylar on both sides so it wouldn't be too hard to experiment with.

Ah that makes sense. Hoping you get it figured out, aside from Line Audio's planned hypercardioid (this probably won't come out for a long time, Rofer can barely keep up with CM4 demand), and 3U Audio's planned CK12, this is what I'm looking forward to the most for upcoming gear.

 

[Scrappersa]

Any worries about body resonances/vibration with switchable parts?

Resonance and vibrations from the swappable parts is something we put a lot of thought into. We actually changed our magnet size/shape/strength and the positions a few times before this final production version. @a soBer Newt and I spent a lot of time on this modifying bodies on his Tormach and 3D printing prototype bodies.

We're now using two strong 1/2" N52 magnets per screen. The back of the screens have a steel surround that directly touches the magnets. They're very secure and we haven't experienced any issues with resonances or physical vibrations since.

We found more weird resonance variations from the physical size of the top section than the swappable screens. This was something we changed a few times as well.

The bigger issue with internal acoustics was comb filtering and weird phase from the screen designs. We initially tried 50 different screen designs for the mic. Around 40 of them didn't sound that great. It was a lot of trial and error, listening and then measuring.

We chose 5 mostly subtle screens though when you start stacking tracks, it becomes apparent very quickly. Going from Motif to Windows can also be pretty drastic on something like drum overheads.

If you really want to make the mic sound bad, try different screen designs on the front and back sides. It can cause massive filtering issues.

Sidenote: The screens are also a lot of fun to snap in. @a soBer Newt and have been known to play magnetic catch where he holds the body and I toss him screens- without a capsule of course. (Though we should do this with a ribbon sometime to show how durable the ribbon is.)

 

[Barry Hufker]

It's great reading about the mic's development and the effort you've put into it. Thank you for revealing some of that background.

 

[gyraf]

the condenser is fixed cardioid (for now!)

The toughest part about making a multipattern version at this point is finding a nice switch that fits and isn't noisy,

..been meaning for a long time to suggest to you that you could do pattern switching in the eventual multipattern model, not by the means of a switch (they're all crappy for this) but by recessed glass reed switches in the mic body: Simply place an additional magnet or magnetic area in a certain part of the replaceable grille so that it gets close to (and thus activates) the reed switch(es) when mounted, in this way "coding" for a certain pattern by switching polarization voltages. Or make the magnet-pattern of grille so that when mounted "other way around"/"upside down", it activates a different set of switches. Reed switches are great at interfacing to these horribly-high impedances btw.

This adds further possibility for coding each side of the mic individually - say front side at +phase and back side at -phase would give you fig8, with +phase at back omni, and at neutral at back a cardoid.. Combine these with a bit of additional acoustic aid from the grille shape itself (cardoid may benefit from a different acoustic termination of the back space than fig8 or omni..), it could be magic..

Jakob E.
I'll raise with a snapshot of some good people at NAMM looking at the Ohma: Spider, Sammy, Tim, Max and Frank..

 

[a soBer Newt]

..been meaning for a long time to suggest to you that you could do pattern switching in the eventual multipattern model, not by the means of a switch (they're all crappy for this) but by recessed glass reed switches in the mic body: Simply place an additional magnet or magnetic area in a certain part of the replaceable grille so that it gets close to (and thus activates) the reed switch(es) when mounted, in this way "coding" for a certain pattern by switching polarization voltages. Or make the magnet-pattern of grille so that when mounted "other way around"/"upside down", it activates a different set of switches. Reed switches are great at interfacing to these horribly-high impedances btw.

This adds further possibility for coding each side of the mic individually - say front side at +phase and back side at -phase would give you fig8, with +phase at back omni, and at neutral at back a cardoid.. Combine these with a bit of additional acoustic aid from the grille shape itself (cardoid may benefit from a different acoustic termination of the back space than fig8 or omni..), it could be magic..

This is one of the nerdiest things I think I have ever read, I LOVE IT!! @Scrappersa looks like we need to stock even more SKUs now!!

 

[Gus]

I seem to remember Joe? of JLM posted using reed switches in microphone in the early 2000's

 

[jarvis]

Congrats on your very unique and cool looking microphone! And Jakob's idea is just the best thing anyone could come up with in regards to pattern switching on your mics, it's just perfect!

Best
Jannis

 

[GeorgeToledo]

I seem to remember Joe? of JLM posted using reed switches in microphone in the early 2000's

Some Neumann and Milab mics that use(d) reed switches come to mind as well.

 

[soliloqueen]

switching the patterns with the grille plates is brilliant, jakob...i love ideas like that, call them "user magic"

 

[SubSpec]

Man, this is truly the most unique and awesome mic development I've seen! Now, most of you here are much more in tune with these developments, I've only recently started paying attention. All the same, super cool to see something so innovative grown with such community spirit as seen here.

Also, the demo videos are absolutely the best mic demos I've seen anywhere. They all seem to not only capture the brilliant performance of the mic but also highlight some tremendously talented artists putting them to work.

Kudos all around! Will definitely end up picking up one of these sooner or later (probably sooner).

 

[Scrappersa]

@gyraf, this is brilliant and something that could be a lot of fun to both use and play with. It could give another reason of importance to the bottom screens other than just indicating the front of the mic. The laser cut screen could even indicate the polar pattern. Love this so much! And yes, I can imagine the different polar patterns would affect the way the screens pickup sound as well. It could be a lot of fun prototyping this.

 

[Icantthinkofaname]

@kingkorg What are the pattern characteristics of the K47 like anyway? I've seen diagrams from Neumann, but I'm more interested in what it's like from a distance or a little off axis. Does it behave like a K67?

 

[kingkorg]

@kingkorg What are the pattern characteristics of the K47 like anyway? I've seen diagrams from Neumann, but I'm more interested in what it's like from a distance or a little off axis. Does it behave like a K67?

k47 is hypercardioid, k67 cardioid. Largest difference in high midrange.

 

[Icantthinkofaname]

k47 is hypercardioid, k67 cardioid. Largest difference in high midrange.

Ah okay. I knew the FET version of the U47 was hypercardioid, I just thought they modified the backplates for it. Seems like it'd be perfect for multipattern mics where you might want hypercardioid but don't want to build the circuit for 4+ patterns.

 

[Icantthinkofaname]

Other than the extended low end, is there any benefit to a capsule like this over a Chinese edge terminated K67? If I were going to build a mic using either this or one one of the Chinese capsules.

 

[kingkorg]

Other than the extended low end, is there any benefit to a capsule like this over a Chinese edge terminated K67? If I were going to build a mic using either this or one one of the Chinese capsules.

These are two totally different capsules. You can think of this one as edge terminated k47.

 

[k brown]

World's first mic that's supplied with a guitar pick!