DOES THE SOUND OF A MIC CAPSULE CHANGE OVER TIME? 

This is actually not news but very well known. And that's why in professional studios we regularly cleaned the diaphragms of the Neumanns and AKGs with utmost care back in the 80's already. There are a couple of videos describing that process. We used 90% Isopropanol and special cleaning buds which are also used in the camera industry to clean lenses. You just have to be super careful or the diaphragm is easily destroyed. Neve use those mics for vocals without a pop filter!

You can definitely hear the difference. While I generally prefer a flat, darker mic sound, in listening to both the new and old capsule the new capsule is clearer and - to my ears - more pleasing.

I'm very conscious of 'spittle prevention' on my condenser capsules. I've actually tested a range of pop screens using a mist spray to see which removes the most spittle from the air. The metal grill types don't prevent spittle at all, while the Hakan style open-foam type seem to prevent the most.

Definitely different sounding. I wonder is the difference due to contamination of the old capsule, or due to it having loosened up (less tension) over time? It would be interesting to hear an NT2A from a few years ago that has not been used - just sat in the box all this time.

This is why SDC's are more sibilant and crisp and LDC's are warmer in comparison. And as far as the damage a mic can take. You'd be surprised. I tried cleaning one of my cheaper mics with alcohol and I guess I rubbed a little too hard, so half the capsule's gold sputtering has been wiped off and still sounds great, less crisp. It's an ST51 and now it has this darker warmer sound like a condenser version of a SM7B. It was a happy accident.

Amazing discovery! Thanks

Interesting - and would make sense. Why I love watching - cheers

There is another factor I believe is the minute differences of tension of the skin of the capsule. I think older capsules skins that have been used a lot have slightly loosened or become slightly more flexible and give a less rigid sound than a brand new one. I think capsules break in a similar way to speakers.

Super interesting. I wonder if you'll start a trend in "relic-ing" new mics to make them sound loogie-filled.

The main effect any type of crud on the capsule will have is probably slowing transient response, and thus top end detail. That all makes sense, it's extra weight on the capsule which needs to be as light and flexible as possible. This probably also means it loses some sensitivity. Now, gold doesn't corrode, but mylar does, and I don't really know what effect the degraded structural integrity of that material has on the sound. The closes examples we can look at are PVC capsules, as they're even less resistant to corrosion and most mics that have those are decades old by now. They seem to suffer from a even more extreme top end roll off, darkening the sound, but it's hard to say whether that's because the material has corroded or because of the crud on the capsule. Then there's also titanium capsules, which are pretty much imperfious to any type of corrosion.

Glad i use my pop filter and the little bag wirh the dessicant pack in it! Very interesting comparing the two diaphragms.

Spittle evaporates and dust weighs almost nothing. More likely that the Mylar thickness was different long ago or something. Or who knows but I just wonder how the notions can be actually tested (frequently analyzer for instance )

This is why I always spray a few dust coats of shellac on all my new capsules before installing them. ;)

Regarding subtle comparison: Hmm you’d have to have the exact same sounds hitting the mic to a/b test things. And the a/b have to touch - no break between

Gives a new interpretation to the phrase "Spit and Polish"!

"Warmer" is a misnomer. I always interpreted 'warmer' as 'brighter'. Decades ago (1973) I asked a CBS engineer if nicotine buildup on the mic. diaphragms made a difference. He said "no", but then again, they weren't doing A/B testing like this. I maintained that nicotine probably did make a difference (remember, everybody back then smoked). Nice presentation, thank you. Bill P.

The louder will always sound better (just like speakers). How are you compensating for volume differences?

Is it possible or more likely that the difference is actually due to the electronics being "burned in" /used more over time? I have high end audio gear (amplifiers ..etc.). They tell you will change (smooth) over time, and it sure has. Same thing perhaps?

I thought you originally replaced the NT2A capsule with the generic K47 capsule, the one from Microphone parts. Did you change the capsule after that or did you say K67 when you meant K47 clone?

Try it with 2 identical DIAPHRAGMS and dirty up one. Maybe some hair spray on it or a tiny bit of spray paint?. BTW they are diaphragms not capsules. :-P

I actuallly like the old capsule lol

But that doesn’t address the issue. You would need to set up a fixed tone set at a fixed distance, then adjust the inputs so the levels are exact.

This don't work, for me the diff is more subjektive than anything else. You should have made measurements for proof. Another thing is the production batch of the capsules, later production series can differ.

How can you have degrees of average?

Probably the same argument exists with guitar pickups how the magnets age?. Nothing stays young forever.

I agree with your analysis and conclusions. Would be interesting to try "sensor" cleaning techniques on the old diaphragm. Maybe imersion in alchohol? Maybe in an ultrasonic cleaning bath? Thanks.

You should pretend to shave using a microphone just to see how cool it looks.

Before shaving, you look in your 70s; after shaving, 50s.