The Sennheiser MD 421-II is a legendary cardioid dynamic microphone widely recognized as an industry-standard "all-rounder" for studio and live sound. The "4" in your query likely refers to the MD 421-U-4 variant, which features a standard 3-pin XLR connector. It is celebrated for its ability to handle extremely high sound pressure levels (SPL), making it a staple for recording loud sources like drums (especially toms), guitar cabinets, and brass.

Key Specifications

• Transducer Type: Dynamic.
• Polar Pattern: Cardioid (Full-bodied).
• Frequency Response: 30Hz – 17,000Hz.
• Bass Control: 5-position bass roll-off switch (ranging from "M" for Music to "S" for Speech) to manage the proximity effect.
• Connector: 3-pin XLR (standard on the II and U-4 models). Thomann +3

Features and Performance

• Versatility: Excellent for broadcasting and voiceover, though some EQ may be needed for a "radio-ready" sound.
• Rugged Build: Features a glass composite housing and hardened stainless steel basket.
• Feedback Rejection: Effective off-axis rejection makes it ideal for live stages and high-transient recordings.
• Common Criticisms: The specialized plastic microphone clip is frequently cited as a weak point, prone to wobbling or breaking. It also has low resistance to plosives when used for vocals without a pop filter.