But on the clarinet, it comes across as robust and pleasing. The MXL 990XL condenser microphone is a substantially enhanced version of the popular MXL 990. The 990XL has a large 32mm capsule that provides a bigger, bolder and more open sound. Mics, mics, and more mics! The MXL 990 remains one of the industry's most ground-breaking microphones. I have no affiliation with MXL - just curious about what the difference might be based on the occasional comment on the 990 sounding "tinny" and what might have been cleared up with the larger diaphram on the XL version. MXL 990 Review. On some instruments it might be called too heavy. If you’re looking for a simple, budget-friendly vocal condenser mic at a great price, read on. You’ll find loads of budget condenser mics on the market for all types of applications. Designed for recording vocals and instruments, it has an upfront and balanced sound. Among the most popular are condenser microphones used for recording vocals. The MXL 990 Stereo sounded the fullest, most rounded.