You can use a dynamic or condenser microphone to capture sound from your acoustic guitar. Directional microphones are often a good option for micing acoustic guitars.
Keep in mind the Stream is not equipped with phantom power (commonly required for condenser microphones). You'll need a dedicated phantom power supply or preamp equipped with phantom power to use phantom power mics with the Stream.
Step 1: Turn your input gain and volume knobs all the way down.
Step 2: Mic your acoustic guitar. Here are a few positioning tips:
Method 1: Using a directional mic: with the mic about 8 inches away from the guitar, place the microphone near the 12th fret, or where the fretboard meets the body of the guitar. For more highs and mid-range frequencies position the mic further up the fret board; for more bass, positing the mic closer to the sound hole.
Method 2: Place an omnidirectional mic a foot away from the sound hole. There is no increased low end due to the proximity effect when using an Omni mic. Move closer or farther away to affect the tonal balance of the guitar and balance the direct sound against the room sound.
Step 3: Connect the microphone to one of the Stream's inputs using an XLR cable. As long as you're using an XLR cable to connect to the Stream, there's no need to adjust the channel's line/instrument switch, as the Stream automatically sets an input to mic level gain and impedance when it detects an XLR connector.
Step 4: While sounding the guitar, turn the input's gain knob to about 25% (9 O'Clock) or to about 1/4 of the way up and set your volume knob to about 50% (12 O'Clock) or about ½ the way up.
Step 5: While playing the guitar at your expected practice volume, adjust the input gain knob until you can comfortably and clearly hear your guitar audio. If you experience signal distortion, your signal may be clipping, in which case you should turn down the input gain knob until the clipping distortion ceases.
Step 6: Adjust the mic positioning for your preferred tone.
For more highs and mid-range frequencies, position the mic further up the fretboard; for more bass, position the mic closer to the sound hole.
If using a directional mic, move the mic further back from the guitar for less bass response and vice versa.
Step 7: Adjust the volume knob to your preferred monitoring volume.