I may be a bad person to answer this since I used to buy microphones like some folks buy hamburgers.
That said, you can purchase a condenser microphone and use it for live performances if you know what you are doing. The tricks to using a condenser microphone live is:
- Set the microphone in such a position that the microphone cannot “hear” either the monitors or the mains.
- The condenser microphone must have a narrow cardioid (or hypercardioid) pickup pattern. Omnis and Figure 8s are out of the question.
- No one touches the microphone after it is set up. A misplaced hand near the microphone element can send the mic on a feedback rampage.
The main problem with using one microphone for recording and live performance is that you are asking one microphone to do completely different tasks. Live microphones are designed to reject sounds that are not in front of them. They also are designed to have an upper midrange bump so that the microphone sounds clearer and cuts through the mix. Also, these microphones do not need to have as wide a frequency response as their recording counterparts since they are used live in systems that are not necessarily meant to cover all frequencies from 20 to 20khz. Recording microphones are meant to be much flatter (less colored) in their frequency response and many are designed to to be used in a wide variety of recording set ups (with musicians circling the microphone “omni” or or either side “figure 8”). In addition, there are lots of different stereo recording set up meant for condensers including X/Y, A/B, Mid/Side and more. And in recording live concerts, sometimes you want the sound of the hall (use omnis or figure 8s) and sometimes you want the recording clean (close mic cardioids). Plus, a decent live microphone (like the SM58) would struggle to record an orchestra triangle or bass drum, or give you a decent recording of an entire string section…etc.
This is one reason I own dozens of microphones.
My suggestion is find a microphone you like and purchase a decent preamp (with lots of clean gain and headroom) for it. Learn how to get the best sound out of your mic and preamp in varying situations (experience is your best teacher here). I’ve recorded live concerts with crappy Radio Shack condensers, lousy preamp onto a cassette and got a pretty nice recording because I knew how to get the best out of each piece of equipment. Here is that recording (unfortunately compressed into an MP3… twice!)