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Originally Posted by Michael_Joly  Since this is the Cheap Ribbon mic thread and I've been a proponent of the Apex 205 as a great value mic, I wanted to toss out this caveat - about 25% of the Alctron ribbon mics I've seen have ribbons that are way to slack in the gap.
When vertical, the ribbon does a sort of double bow in the gap because it is too long. The ribbon can be heard to be scraping against one of the magnets when the mic is moved back and forth in the air. When held horizontally, the ribbon bows almost completely out of the gap in the center. This would cause non-linear response and low output.
Fixing this problem is straightforward but delicate. One or both of the ribbon clamps must be loosened and removed. Then the ribbon pried gently away from the lower clamp surface. Occasionally the ribbon is fused to the clamp surface and cannot be moved without tearing. In this case the last resort is to hope the other end of the ribbon can be freed from the clamp and pulled taught.
This problem is not visible with the stock headbasket mesh and inner waffle plate installed. But it is worth disassembling the mic to inspect the ribbon placement and tension to make sure you're getting all the response the mic is capable of. |
Good point, Michael. I found this problem in my HRM10, and I was able to fix it myself, but I'm not sure I'd recommend anyone else try it unless they were quite willing to treat the mic as an experiment - the ribbon is quite fragile.
If you are going to try it yourself, be sure to completely remove the plate that holds the ribbon in place. Don't just loosen it - you WILL tear the ribbon. Once it's removed, you can use the tip of a jewelers screwdriver to gently lift the end of the ribbon from its place.
Now one end of the ribbon is loose, and you need to refasten it - with appropriate tension. There is no way to simply put it back and retighten the plate. So instead, take a QTip soaked with alcohol (pure isopropyl, not "rubbing alcohol") and wet the place where the ribbon needs to attach. Then, using the same QTip, place the end of the ribbon back in place. The wetness (surface tension) of the alcohol will be enough to hold the ribbon in place while you refasten the plate that will hold it permanantly.
Be careful to make sure that it is adjusted properly. The ribbon should be parallel to the magnet assembly all the way up and down, and it should sit nicely in the gap without touching either side. It should be tensioned loosely, but not loosely enough to let it fall out of the gap when the mic is horizontal. There should still be plenty of corrugation visible in the ribbon.
When you've got it right, be sure to store the mic vertically so you don't run into this problem again.