The Sennheiser MD 409 is a dynamic microphone great for both in the studio and on the stage. I have only used this microphone in the studio, but have seen it used in a live setting as well. Only one of the sides of the microphone will pick up, which is what makes its such a great microphone for micing guitar amps. The MD 409 has been around for a while and has become ubiquitous in studios and on stages alike.
I've been using the Sennheiser MD 409 for about four years and have found them to be one of the best dynamic microphones I have used and are great for a number of different applications. Due to the nature of the way this microphone is shaped, it is great to put up on the grill of an electric guitar amp. It also sounds great on tom tom drums and vocals. I have seen the MD 409 used for vocal mics on stage a number of times, including in Pink Floyd's Live at Pompeii. However, its best sound application is probably for electric guitar amps as it really shines in this scenario. It also sounds great on horns - specifically saxophone. Sennheiser has a lower end model of this microphone known as the e609, and while the e609 is a great deal for the price, the MD 409 is the original and reigns supreme. The sound quality of the MD 409 is full and crisp and always delivers a great tone for me. The price isn't too expensive for a great dynamic microphone like this one, but it isn't the cheapest microphone on the market either. The Sennheiser MD 409 has become a classic mic and Sennheiser has a great reputation for making great sounding microphones that are reliable. I highly recommend this microphone for studio owners and anyone looking for a great dynamic microphone.