What watt receiver shouid you use for xls-15 speakers?

That depends on the speaker’s power rating and impedance, but for most XLS-15 speakers you’ll want a receiver or amp that can deliver clean power within the speaker’s recommended RMS range. As a general rule, choose a receiver whose RMS output per channel matches or is slightly higher than the speaker’s RMS rating at the correct ohms. Having a bit of headroom is better than underpowering, which can cause distortion and damage the speakers.