mid/side mic question

[Drew Stephenson]

Ah, that makes sense. Orders of magnitude difference in precision I'm guessing.

[Hugh Robjohns]

... I'm not aware of any alternate ribbon materials.

"Roswellite"

Developed for and first used in the Crowley & Tripp El Diablo ribbon microphone as well as their Naked Eye mic:

https://www.soundonsound.com/reviews/cr ... -el-diablo

...which is now sold as the Shure KSM313/NE (and also used in the KSM353/ED) ribbon mics.

As I said in the Diablo review, "The true nature of the Roswellite ribbon material used in the El Diablo is a closely guarded secret, but Crowley & Tripp have said that it's "a new class of advanced materials called 'Supermatter', which is engineered with nano-scaled structures that provide incredible strength and durability".

Furthermore, apparently it "retains a memory for its original shape" that enables it to survive high-SPL applications such as miking kick drums.

Not only can Roswellite handle high SPLs, it isn't bothered by wind blasts or phantom power and it won't sag or stretch, as traditional aluminium foil ribbons tend to, either.

Shure describe that patented material as "acoustic nanofilm." It's an extremely strong, low mass, superelastic, paramagnetic composite with high inherent conductivity and shape memory properties.

[forumuser840717]

Over the last decade or so, various people/companies/institutions have been researching and prototyping mics which use graphene as a diaphragm/diaphragm substrate, including some ribbon elements using graphene doped with aluminium oxides, but Im not aware of any being in production or production-ready, other than (possibly) in some MEMS designs. (Not sure whether they're commercially available yet, or just being tried.)

[Wonks]

... I'm not aware of any alternate ribbon materials.

"Roswellite"

Developed for and first used in the Crowley & Tripp El Diablo ribbon microphone as well as their Naked Eye mic:

https://www.soundonsound.com/reviews/cr ... -el-diablo

...which is now sold as the Shure KSM313/NE (and also used in the KSM353/ED) ribbon mics.

As I said in the Diablo review, "The true nature of the Roswellite ribbon material used in the El Diablo is a closely guarded secret, but Crowley & Tripp have said that it's "a new class of advanced materials called 'Supermatter', which is engineered with nano-scaled structures that provide incredible strength and durability".

Furthermore, apparently it "retains a memory for its original shape" that enables it to survive high-SPL applications such as miking kick drums.

Not only can Roswellite handle high SPLs, it isn't bothered by wind blasts or phantom power and it won't sag or stretch, as traditional aluminium foil ribbons tend to, either.

Shure describe that patented material as "acoustic nanofilm." It's an extremely strong, low mass, superelastic, paramagnetic composite with high inherent conductivity and shape memory properties.

Also I assume in the AErA 51.

[Sam Spoons]

I'll look into that one. I have a couple of MXL Cube LDCs which are much better than their price suggests.

My MXL Ribbon arrived today but I haven't tried it yet. The problem is I use a digital desk and regularly switch between different scenes*, these scenes save the spook power status of every mic channel so if I switch scenes it could turn 48V on the mic channel the ribbon is connected to. I know this probably won't cause damage but I'm reluctant to risk it as it is bound to happen at some point. So I looked for a Phantom Power Blocker circuit. Long story short I went one stage further and bought a Fethead preamp as the extra cost was relatively small over the basic spook blocker. It will live in the box with the ribbon mic and a short link cable so, hopefully, I'll be unlikely to forget to use it.

I could go to the trouble of setting 'safes' for every scene so that p48 stays off on the channels I might use the ribbon on but I'm bound to forget eventually and use a different channel previously set up for a DI or capacitor mic...

[Hugh Robjohns]

Sounds like a good way of achieving peace of mind... but I spent the best part of 20 years hot-plugging ribbon mics (via XLRs) with phantom on the line almost daily, and not one ever died as a result. It is a very greatly exaggerated risk IMHO.

[Sam Spoons]

Yeah but you weren't hot plugging a budget ribbon into a Behringer mixer ... Either way I considered the Fethead would be a useful addition to the toolbox and I've been thinking about buying one anyway...

[Sam Inglis]

I have never had any real world problems from being careless with phantom power and ribbon mics. I did once have a real world problem from being too careful though! I plugged a ribbon mic in, it didn't work, and I later realised it was an active ribbon that actually needed 48V...

[Drew Stephenson]

Doh! I have just been reminded of doing exactly that.

[Hugh Robjohns]

[ef37a]

Yeah but you weren't hot plugging a budget ribbon into a Behringer mixer ... Either way I considered the Fethead would be a useful addition to the toolbox and I've been thinking about buying one anyway...

They weren't HIS mics either! I think you are being unfair to Behringer, a much greater risk would be a manky cable! That last is based in the idea that a ribbon mic can suffer damage if the cable has lost one core circuit and a net current flows through the transformer? But then, AFAIK ribbon transformers are not referenced to the shield so I am still no nearing knowing how this effect is supposed to happen?

Dave.

[James Perrett]

But then, AFAIK ribbon transformers are not referenced to the shield so I am still no nearing knowing how this effect is supposed to happen?

Certain ancient RCA ribbon mics used a centre tapped transformer with the centre tap connected to the shield. If you applied phantom power to these mics then there would be current flowing through the transformer. These mics were designed well before the introduction of phantom power but were mainly confined to broadcast studios and high end commercial studios so there are unlikely to be many of them about, particularly on this side of the pond.

If you have a microphone with a 3 pin XLR on it made after about 1970 then it should be compatible with phantom power. If it has a different connector then you need to know its internal connections before you make up an adaptor lead.

[Hugh Robjohns]

As James says some very early ribbon mics used centre-tap-grounded output transformers, which could result in DC through the coil if one cable leg either went open, or shorted to the screen.

(And, depending on the construction, the transformer could be upset by the current flowing in each half, too, even with a good cable).

And similarly, with a modern floating output transformer, one leg getting shorted to screen in the cable will result in DC through the coil.

In such cases, the ribbon would be forced outwards, potentially stretching it or even tearing it.

But it's got to be a very poorly made and badly abused cable for any of that to happen. I can't remember the last time I had to repair one of my mic cables...

I've been told apocryphal tales of such ribbon-ripping disasters occurring, but I've never experienced it myself and I don't think I know anyone else who has experienced it first hand either.

[Aled Hughes]

Hugh’s point is consistent with what I’ve experienced as well - I use ribbon mis very often, often hot-plugging with phantom power without giving it a second thought, and I’ve never ever encountered a problem.

However… there is one situation where I get nervous with them: our patchbay serves up the mic outputs on bantam jacks, and if I were to hot-plug them via the patchbay to another preamp/mixer channel that had phantom enabled, then I imagine I could well be in trouble.

For me personally that’s almost a non-issue as I’m not really into the whole trying mics into different preamps thing, but it’s something to keep in mind when other engineers are in (or not mention the patchbay facility… or hide my ribbons…!)

[Drew Stephenson]

When I asked Stewart Tavener (Xaudia / Extinct Microphones) about this I think he said he'd never had a mic on his repair bench because of that problem.
Bit of myth-busting from 7:58 here https://www.soundonsound.com/people/ext ... er-podcast

[James Perrett]

When I asked Stewart Tavener (Xaudia / Extinct Microphones) about this I think he said he'd never had a mic on his repair bench because of that problem.

I was just wondering what Stewart's take on it would be before reading your post Drew. If he's never seen it then I suspect that the problem is virtually non-existent.

[Drew Stephenson]

I suspect that any centre-tap ribbons that have survived and are still in use are in the hands of very careful owners.

[Dynamic Mike]

Yeah but you weren't hot plugging a budget ribbon into a Behringer mixer ... Either way I considered the Fethead would be a useful addition to the toolbox and I've been thinking about buying one anyway...

My R144 arrived from Andetons over the weekend. I've not recorded anything yet but just checked it worked today. It sounded nice on acoustic guitar but needs pretty much all the gain my Zoom R8 interface has available so I'm guessing it'll be noisy. Also I could only find a really long lead to test it with which I'm guessing probably didn't help.

I'm happy to add a Fethead but given I no longer need the portability of the R8 wondered if simply swapping to an SSL Mark II interface would offer more clean gain?

The shockmount included doesn't seem to do much in the way of isolation but I think that's possibly because the mic is very light. I'll only be using it on acoustic guitar and vocals at home so not really a problem for me.

[ef37a]

Mike, since ribbons are said to be best stored vertically why not give it its own dedicated stand and attach a small die-cast box containing two isolating capacitors and associated 'tie down' resistors? Naturally you put a bag over the mic when not in use.

I did similar for my RB but since it is the 30 Ohm model I bought a 1:4 transformer from Sowter (best part of a nifty IIRC!). That gave a useful close to 12dB signal boost and of course protected the mic from spook juice. It did not unfortunately help with hum pickup which is a consequence of the mic not having "bucking" wiring.

Dave.

[Arpangel]

Mid/Side, I've got all the stuff to do it, but never do it! it's such a faff, for very little returns IMO, I like the idea of it, but then think, nah, I'll just put up a couple of cardioids.

[James Perrett]

Mike - the long lead shouldn't make any difference - it is very common to use 30m or longer cables on mics via multicores in a live situation or in a large studio. I'm not sure which mic preamps are used on the R8 but if it is the same design as the H series recorders then you'll probably find the SSL slightly quieter. If it is the same design as the F series then the SSL won't be an improvement.

[Sam Spoons]

Thanks for all the myth busting guys, makes me feel a little more secure about using the MXL in the studio.

I think you are being unfair to Behringer, a much greater risk would be a manky cable! That last is based in the idea that a ribbon mic can suffer damage if the cable has lost one core circuit and a net current flows through the transformer? But then, AFAIK ribbon transformers are not referenced to the shield so I am still no nearing knowing how this effect is supposed to happen?

Dave.

I don't even know if this one has a tranny (surely it would have to wouldn't it, an aluminium ribbon would have a very low resistance indeed)? And, assuming it does, wouldn't that would protect the ribbon from DC?

FWIW the MXL manual says "Never intentionally or accidentally apply power to the microphone as it can permanently damage the ribbon element." hence my concern.

[ef37a]

Thanks for all the myth busting guys, makes me feel a little more secure about using the MXL in the studio.

I think you are being unfair to Behringer, a much greater risk would be a manky cable! That last is based in the idea that a ribbon mic can suffer damage if the cable has lost one core circuit and a net current flows through the transformer? But then, AFAIK ribbon transformers are not referenced to the shield so I am still no nearing knowing how this effect is supposed to happen?

Dave.

I don't even know if this one has a tranny (surely it would have to wouldn't it, an aluminium ribbon would have a very low resistance indeed)? And, assuming it does, wouldn't that would protect the ribbon from DC?

FWIW the MXL manual says "Never intentionally or accidentally apply power to the microphone as it can permanently damage the ribbon element." hence my concern.

Yes, it will have a transformer in it and that is very unlikely to be centre tapped, why would you? So, no net current can flow through it and 'bend' the ribbon that way. I have to admit I had not considered Hugh's scenario of a cable core short to shield but I agree, an extremely rare eventuality. Buy a 20 quid cable tester?

The warning in the manual is the usual blood sucking lawyer's arse saving exercise! But! If you are really still worried? Two caps in a tin!

Dave.

[Hugh Robjohns]

I think MXL are just covering their legal back and warranty claims department...

The issue with phantom is not DC current flowing through the ribbon itself. As you say, they all have a transformer between the ribbon and the mic cable.

The problem is a transient thing. If DC is applied across the transformer, that transient step change in voltage as it is applied will generate a step change on the ribbon side which will momentarily kick the ribbon out of the magnetic gap with quite a lot of energy... and that's when the potential stretching or tearing damage could — in theory — occur.

In practice, it's more fear of the imaginary dragons than real zoological creatures.

[Dynamic Mike]

Mike - the long lead shouldn't make any difference - it is very common to use 30m or longer cables on mics via multicores in a live situation or in a large studio. I'm not sure which mic preamps are used on the R8 but if it is the same design as the H series recorders then you'll probably find the SSL slightly quieter. If it is the same design as the F series then the SSL won't be an improvement.

Thanks. I'll try with the Fethead first and maybe change the interface later as part of a general decluttering.