Troubleshooting Mic Repair: October 2016 Question of the Month
Shure Notes email newsletter subscribers submit their burning audio questions every month, and we pick one to publish in the email and here. This month, we focus on when to give up on DIY microphone repair.
Do you have an audio issue that's driving you nuts? Are you wondering which mic, wireless system, headphone, or phono cartridge is best for you? You're not alone.
Shure Notes email subscribers are a curious and creative bunch. If you join their ranks, then every month, in our digest of audio how-to tips, product info, artist news, and events listings, you'll see the latest subscriber question followed by the answer from one of our expert support engineers. Plus, you'll get the chance to ask your own question by clicking the "Ask Us" button in the email. We'll pick a question every month and publish it in Shure Notes. A few weeks later, we'll also publish it here on the Shure Blog.
Steve in Texas asked:
I have an SM57 that's been in my arsenal of microphones for many years. A few years ago it lost all of the low end. I replaced the cartridge with an OEM and was back in business again, until I miked an amp by laying it over the top (not in an adaptor). The plastic windscreen rattled, so I placed electrical tape around the windscreen. Then all of the low end went away again.
My questions are two:
- Will the diaphragm harden, or become brittle, over time and change the response curve?
- When I used the plastic tape, did it prevent the diaphragm from responding to low frequencies by not allowing complete airflow over the diaphragm?
Our product support team answered:
Sorry to hear about your SM57. As with many items, a mic will degrade over time. This is usually a combination of use and environment. Usually what causes a mic to lose its correct response curve is debris or corrosion from saliva. It weakens or unbalances the diaphragm. Also buildup along the grille can severely impact the pickup pattern and response of a mic.
In your case, the tape did disturb the proper airflow of the mic. Also, your understanding of the airflow is correct. The main grille (2) and the secondary grille that lies between (2) and (8) aid in the natural pickup of the mic. It's possible that tape could impede their intended function. Unfortunately there isn't a quick fix to get the grille back on correctly. You may have to send it into service for a replacement.
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