The plague has killed our conversation

[WK154]

What part of OZONE being corrosive don't you get?

[JohnMHoyt]

What part of OZONE being corrosive don't you get?

Worth a shot at trying... They have been doing their phone handsets, mic, cell phones, etc for years apparently, with no issues that they have ever noticed.   They even do entire notebook computers in their larger one.

[WK154]

I'm sure that Shure and Sennheiser will love you as you will eventually have to buy new mics. The applications you mentioned (speech) are not this application nor are the cell phone mics (MEMS). A C rating is not good for Polypropylene.
"C    Fair    Ozone will break down these materials within weeks of use. Prolonged use with any ozone concentration will break down or corrode these materials beyond usefulness." a rating for Polypropylene (Mylar).
You've been warned.

[JohnMHoyt]

Thanks...  I think it'll be okay....   I am looking into hydrogen peroxide vaporization too..   I see a huge need for experimentation sooner than later.

Just had a discussion with a friend with DHEC who said microphones and shared devices will be part of ongoing regulations here when we begin to open back up.

That will affect me I'm several aspects so I'll need to be ahead of that

[Artaudio]

John,

This will be awesome to see how the mics will hold up. It would be good to give the lab a good (58 or something similar) and test it before it goes to them (to get a base line) and then do an "after" test to see if there is any degradation both sonically and visually. I would even have them keep it for a couple weeks and bombard it daily. Just to see if the mic holds up. If ozone is this corrosive, there should be some degradation within a couple weeks if not sooner.

Pass on our thanks to your friend for reaching out.. Its too bad that we couldn't arrange a more formal test using the different methods, and compare.

Does anyone on here have any connections with the mic companies? Maybe they might see it beneficial to put a couple sampler mics to the test. Its in their best interest as well.

I could contact my Shure distributor here in Canada but I don't think I can easily get a mic to you in a timely fashion.

Cheers
Al T

[Artaudio]

What part of OZONE being corrosive don't you get?

No disrespect. But I think we have to keep our minds and options open until we have some definitive proof. From what John is telling us, it sounds like the hospitals have been doing this for some time with some measure of success. It may be enough to work for us in our industry. If it diminishes the life span of a microphone from 5 years to 3 years, it might be something most companies can live with. The mic is only subjected to 8 min to be fully sterilized. I think it would take a quite a few treatments before you'll see any changes. But you never know until you try. Right!

 I do understand your take on condenser mics. I don't think I'll be subjecting my Neumans to the Ozone machine anytime soon.   Like I said in earlier posts, I would remove the mic grill (both my 58s and Beta 87's) and put those in the Ozone and just keep another set of grills in rotation. But it would be interesting to see how much a mic can handle before it stops working.

Al T

[WK154]

No offense taken. Let's first understand the problem. You are trying to disinfect the Mic screen and internal foam insert, not the mic capsule. For that the method you are proposing will work just fine since no capsule is involved. It may over time cause deterioration of the foam screen and it will need to be replaced. A solution except for the UV/Ozone equipment cost. The IPA solution is also a proven solution by Hospitals if that matters but at a far less expensive investment. The foam will also have to be replaced over time. There is no real difference in time for these procedures so why spend the money? High end mics usually have dual wire mesh screens such as the Neumann KMS105's and are much quicker to clean. 92% IPA dries quickly. If you want to involve any electronics or the capsule you'll have a problem sooner than you think. SM57's are another story for another day. In the end it's your mics and your $'s.
Cheers

[JohnMHoyt]

So I really liked the idea of getting a baseline for the mics before doing a test...

I can dedicate a couple mics to this project:
Shure SM58
Shure SM58 beta
Sennheiser e835
Chinese import wireless sold under Gemini, Rockville, Xtuga, Nady names

I could create a test bed using a speaker, with a known signal source, such as a sweep, at a known volume (using a calibrated dB meter).
I would obviously use the same mic/speaker placement each time (I can give up a portion of my office to leave this set up in fact).
Do it twice per mic & record it.

Give the mics to them and ask that they run them through 10 minutes a day for a week and re-test.
And repeat that for a month or so.

He also mentioned they have been running their chapel's handheld mics from their Shure ULX system, along with a Countryman headset and the podium mic through the CoolClave for month.
He doesn't have an exact start date because the guy who started doing that is no longer there, but it's been at least a month.
Nor does he have any kind of baseline obviously.

Additionally, they are also using UV cleaning units in each room like the Chapel for 15+ minutes a day, so ALL electronics are being exposed to ozone.

They roll all their portable monitors, carts, tablets/handhelds etc into a room, spray them with alcohol and wipe them down, and then seal the room and run UV in there, and flush with fresh air.
That's happening daily, sometimes multiple times a day.

He wasn't supposed to mention this, but they are also cleaning their PPE in the same manner because they are limited in the "good face masks" apparently.  People like janitorial staff only get one mask per day.
This is NOT approved and against their policy, but the staff is very paranoid according to him.

[JohnMHoyt]

I have also purchased my own UV lights, several different brands, and will create a case to put them in that holds 12 microphones around a single UV source in a closed 12x12x12" box that I can vent outside.

[WK154]

Don't get me wrong I've been using UV/Ozone technology for over 20 years. It all started with my wife's classroom where I installed several unit's in an effort to keep her from the seasonal issues successfully I might add. I also installed it in our HVAC. I am currently sitting a couple of feet from a room air purifier that consists of several UV-C lamps a HEPA air filter and a carbon filter running at a low setting continuously. Here is a company that certainly knows about Ozone and its pros and cons. 
 https://www.ozonesolutions.com/knowledge-center/ozone-compatible-materials.html
If your friends test show little to no effect it is probably because the Ozone is not reaching those parts. UV does not pass thru solid objects, ie. grills and foam. Its not a one size fits all solution.
This technology came from the Space program decades ago.

[WK154]

On the subject of Hydrogen Peroxide vapor I wouldn't want to subject any audio gear to 248 F temperatures. I can see it as a autoclave solution. If however you have the time for drying Peroxide is as effective as IPA. Don't buy the pharmacy variety since it contains some unknown stabilization agent. I purchase a 35% food grade solution from a reliable manufacturer and dilute it with distilled water with caution. It's used in the food industry to disinfect slaughter houses to kill all kinds of nasties. I use it as a mouthwash and topical disinfectant at 3-4%. That use has been around for many decades. Typical dilutions is from 3-6%.

[Artaudio]

Hey everyone,

Take a look at DPA response to cleaning microphones.. Tell me what you think.

https://www.dpamicrophones.com/mic-university/proper-mic-hygiene

Cheers
Al T

[WK154]

First you need to establish what contaminants you are trying to clean from a diaphragm. I would suspect cigarette smoke film and foam particles from aging foam. All manufacturers recommend distilled water as a cleaning fluid (the universal solvent) but by itself it is not all that effective. Adding a surfactant such as Dawn or others in low 1% concentrations will help. I would discourage any mechanical cleaning with a soft brush. Low power Ultrasonic  (20-40KHz) jewelry cleaner for a short time may be better (not for MEMS and other Piezo pickups). In all cases a distilled water rinse should follow with a long drying period (72hrs). Leaving another type of film defeats the purpose of cleaning. Soap as used by DAP's description is too generic a term with many soaps containing undesirable content for this purpose. Remember that the devil is in the details and the cure may be worse than the ailment
Cheers

P.S. the exception being Shure that discourages even distilled water    They'd rather you buy a new mic or at least a new capsule. So much for driving nails with a Sm58 

[WK154]

Here's Josephson's take on this.
"More than twenty years ago, we posted some comments to rec.audio.pro about
cleaning condenser microphone diaphragms. I have decided to retire the local
copy of that article, because it seems to inspire too many to attempt things
that are unwise.

One thing left out of the original article is this: cleaning should only be
done if the microphone fails to work otherwise. The difference caused by a
little extra weight may be audible, but not huge. Got that? No cleaning unless
it *doesn't work.* And in no case should you use any source of heat near the
microphone. Someone thought that what we wrote suggested putting steam on the
microphone diaphragm. !!?! ...  the steam is to put a slight amount of pure
water on your cleaning brush, not the diaphragm! No heat anywhere near
diaphragm, OK?

With all due respect to others in the field, if the conductive layer on
the diaphragm is so fragile that gentle cleaning with distilled water, alcohol
and cotton or a slightly damp fine brush damages it, you have no business
cleaning it. That said, losing a small amount of metallization has little or
no effect -- the diaphragm will still behave as it did before, the
active area is just reduced a little. A real hazard, however, is that the
capsule will become contaminated internally with whatever the cleaning medium
carries with it, and will forever be noisy. This is particularly a problem with
older PVC diaphragms that have cracks. Unless you have a way to test for
ionic contamination of the surface and resulting leakage resistance of the
capsule, don't try it.

If any Josephson microphone appears to need cleaning, please send it back to
the factory in California. The cost is minimal and you can be sure of original
performance when it's done."
All kinds of opinions.
Cheers

[WK154]

One other note. Each microphone will require a different way of cleaning, there is no one size fits all solution. Some will certainly be similar but most are not.