Oh my, that’s a dirty microphone capsule. Time to give it a little bath!

Follow along with Derek as he cleans a vintage Neumann U87 condenser capsule for RaxTrax Recording!

Have a vintage or modern condenser microphone that isn’t performing properly? Need Your mic capsule cleaned? Send a message to Derek at derek@vanguardaudiolabs.com.

 

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Have a Vintage or Modern condenser microphone that isn’t performing properly? Need Your Capsules cleaned? Send a message to Derek at derek@vanguardaudiolabs.com.

Why The Cleanliness of Your Condenser Microphone Capsule is Important

Condenser microphones are sensitive and delicate, especially their capsules, which require particular care. The capsule of a condenser microphone is incredibly sensitive, often composed of a thin diaphragm that captures sound waves with extremely high precision. When dust or dirt accumulates on the diaphragm, it can distort the sound, reducing clarity and causing issues like hiss, rumbling, or even a complete loss of sound. In more severe cases, moisture build-up can lead to corrosion, potentially damaging the microphone permanently.

If you’ve ever used a microphone that starts making rumbling “ocean” noises when used on a vocal (or even just sitting on the stand), it’s quite possible that a dirty capsule diaphragm is the culprit. Vintage microphones in particular, with their years of vocal use, can accumulate a lot of grime on the capsule diaphragm.

Over time, dust, moisture, and particles can accumulate on the microphone’s capsule, leading to reduced sound clarity, distortion, and even malfunction. Regular cleaning ensures that your microphone maintains optimal performance, extending its lifespan.

How To Prevent Your Condenser Capsule From Getting Dirty

Don’t want your mic to look like the photo above? Here are some basic tips for preventative maintenance on your condenser microphones.

1. Use A Pop Filter For Vocals. Most of the microphones I receive have some amount of spit residue. Using a high-quality pop filter like the Stedman ProScreen protects your investment.
2. Store Your Microphone Properly. Don’t leave mics uncovered on the stand when you turn off the lights after a session! Condenser capsules retain a tiny electric charge, even when phantom power is disengaged. That electric charge attracts charged particles of dust. Yes, your microphone has a grill that helps keep dust out, but it won’t block ALL the dust. Vanguard sells lint-free microphone covers specifically for this purpose, but a Ziploc bag works in a pinch.Ideally, store your mics in a storage case or bag. HOWEVER, the foam inside those cases, especially as it ages, can shed and make the diaphragm even dirtier. I always recommend storing microphones inside a Ziploc bag, with a silica dessicant packet inside the bag. This will keep your capsules very clean.
3. Never Smoke Around Your Condenser Microphones. The buildup of smoke residue makes the dust even harder to get off. This is probably the worst thing you can do around a condenser microphone capsule, and the hardest cleaning jobs I get often come from smoke-filled residue.
4. Never Take Apart Your Condenser Microphone And Leave the Capsule Exposed. This is how capsules get damaged, and damaged capsule diaphragms can’t be cleaned. They often need a full re-skin, which can result in repair bill that can run $500 or more.

Why Cleaning the Microphone Capsule is Crucial

Routine cleaning ensures that the microphone continues to function at its best. However, because of the fragility of condenser microphones, cleaning the capsule can be tricky. Improper cleaning methods can cause more harm than good, which is why many professionals recommend leaving the job to experts. The conductive gold layer on the capsule diaphragm is critical to the function of the microphone, and damage to the gold layer or the Mylar substrate can turn your prized studio microphone into a very expensive doorstop.

What Experts Use to Clean Condenser Microphone Capsules

Professionals in audio engineering and microphone maintenance use specialized tools and techniques to safely clean condenser microphone capsules. These include:

• Anti-static soft-bristle brushes: Designed to gently remove dust without damaging the sensitive diaphragm. High-quality sable artists brushes are fantastic for this.
• Compressed air: Some folk use compressed air in short bursts to blow away particles without applying direct contact. I try not to do this as older capsule diaphragms can be quite fragile. If I have to use any air, I’ll use gentle blasts parallel to the diaphragm surface.
• Distilled Water: Used sparingly to clean stubborn dirt build-up, smoke residue, and spit particles, ensuring no gunk is left behind. I don’t use this if I can avoid it, as older capsule diaphragms can have a very poor gold-to-Mylar bond!
• IPA: No, NOT the hipster beer, Isoproyl Alchol! Some folks will dilute 99% IPA in their distilled water. Once again, I avoid it, as IPA is a solvent that can ruin the crucial gold layer on the condenser microphone capsule diaphragm! I will, however, use IPA to clean surrounding components and the inside of the headbasket before I rebuild the microphone.
• Lint-free cloths: I use lint-free cloth to wick distilled water off the capsule diaphragm, ideally without making any contact with the diaphragm surface.

Why You Should Leave It to the Experts

Cleaning a condenser microphone capsule is not as simple as it may seem. Given how easy it is to damage the delicate diaphragm or internal components, any DIY attempt can lead to very costly repairs or permanent damage to the microphone.

Here are some reasons why experts should handle the cleaning:

• Precision Handling: Experts know how to safely disassemble and reassemble microphones without causing damage. They understand how to handle the capsule without introducing new contaminants.
• Specialized Equipment: The tools used by professionals are specifically designed for cleaning sensitive audio equipment. These tools minimize the risk of damaging the capsule.
• Experience and Knowledge: Experts are familiar with the specific needs of different microphone models. They can identify and address issues like corrosion, moisture damage, and faulty connections that may not be visible to an untrained eye.
• It Only Takes One Mistake. Capsule diaphragms are extremely delicate. They typically run from 1 to 12 microns thick, which is a fraction of the thickness of a human hair. One wrong move can ruin your entire condenser capsule and your microphone will no longer function.

Conclusion

While cleaning is essential to maintaining the performance of a condenser microphone, the task of cleaning its delicate capsule should not be taken lightly. Professional mic nerds have the tools and expertise to ensure your microphone stays in top condition without risking damage. For those who rely on their microphones for studio-grade performance, leaving this task to an expert can save you from costly repairs and preserve the integrity of your equipment.