Options for connecting XLR mic to computer KVM via aux?

Question

I recently purchased a Shure SM7B microphone to use in an entry-level home studio, but I want to be able to switch it between multiple desktops. I already have a KVM for switching all of my other peripherals, so I'd prefer to use that if possible vs another device. Popular recommendations like the Focusrite USB audio interface would work, except the only free port I have available on the KVM is aux input. The standard USB -> aux adapter, like this one, have extremely poor ratings and seem unreliable, so I'm hesitant to go that route.

Is this just a limitation of aux and I'll have to take on another USB connection? Or is there some series of devices/adapters that would reliably get me from my XLR microphone to aux on my KVM without compromising audio quality?

Answer 1

The SM7B as well as most dynamic mics are known to have a very low output level. Many "standard" USB sound cards struggle to amplify the signal enough to get a useable result. It is not uncommon to add extra amplification, such as a Cloudlifter. When amplified enough it has a bit of a dark sound with lots of rejection from the environment noises. Some love it, some less.

You will have to get either of:

• A decent USB sound card which you can switch (good idea to get that USB hub). In my experience you will need above 50dB amplification, meaning that not all sound cards works standalone. Alternatively get a soundcloud (try first, you might not need it).

• Or, a microphone preamp that you can connect between the mic and the aux input. Again, you will need a quite a bit of amplification so it might be good to be able to test before you start buying.

Note: The Cloudlifter i mention is actually one brand, there are probably several others. The work by eating phantom power (48V) from the preamp/USB card and amplify the mic signal by something like 20dB. They are only useful for so called dynamic microphones.

Note: In my mind, the SM7B is a bit overhyped. I get about 95% of the sound for less money using a SM58 or SM57 with a bit of extra wind protection. Not as cool looking though.