Nady RSM-4 - Review and Opinion

These ribbon mics have been reduced to $79 at a major online retailer. At that price, a Premium ribbon microphone modification from OktavaMod is a must-have upgrade (especially given the ribbon tension problem that some of these mics have right from the factory - see below).

Ribbon mic are simple devices, but a big part of their sound is the output transformer. The OktavaMod Premium modification for your RSM-4 ribbon mic swaps in a Lundahl tranny for better time and frequency domain performance across the audio spectrum.

Lundahl (family-owned and operated in beautiful Norrtalje, Sweden since 1960) is a leading manufacturer of high performance transformers for the professional audio industry. With ribbon mics, it just makes sense to go with a product from a company with nearly 50 years of specialty R&D and manufacturing experience in the field of professional audio transformers.

This is Michael Joly writing, the guy behind OktavaMod. You're invited to contact me directly to discuss your mic needs and discover if the Premium modification for your RSM-4 ribbon is right for you.

In addition to the Lundahl transformer installation, the inner headbasket screens are removed to reduce standing wave reflections and smooth frequency response. Next, I replace the stock 6 micron ribbon with a lighter, 1.8 micron, more responsive 99.9% pure aluminum ribbon.

Stock Ribbon Sag

About 50% of the two hundred or so mics of this type I've seen have come from the overseas manufacturer with improperly tensioned ribbons - often with 80% of the ribbon length sagging out of the magnetic gap (below).



Notice the ribbon sagging in a "footbridge" fashion. This ribbon sag causes low output, "clanging" noise, excessive sensitivity to low frequency rumble and high distortion - all of which can be eliminated with proper ribbon tension. The new 1.8 micron ribbon will be properly tensioned for best low frequency response and minimal footfall vibration pick up.

You can check your RSM-4 (or any other ribbon mic) for ribbon sag very easily. Listen to the mic in headphones, gently tip the mic back and forth so first the front face, then the back face comes to rest parallel to the floor. If you hear a sudden "clang" or "clunk" this indicates a severely under tensioned ribbon flopping about in the magnet gap. Not good.

Once modified, the high frequency response and output level of this mic is right up there with the best of them. And the medium length 35mm ribbon offers a musically useful low frequency resonance without accentuating unwanted LF rumble.

Click "Add to Cart" to purchase the Premium mod for your RSM-4 ribbon - you'll get an immediate confirmation email of your order. By the close of the next business day you'll receive a personal email with your scheduled modification and return ship dates. Questions? Just click "Contact Me" - best, Michael

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Award-winning Microphone Design by
Michael Joly