Are you using the DMAS with an 8KX? The DMAS are high-impedance speakers and don’t work in standard audio ports. Plugging regular headphones into an 8KX would result in extremely loud sound (and may damage the headphones).
Try adjusting the volume via the 8KX volume buttons. I noticed that the headphones ignore the main Windows volume setting. You must use the headset buttons to adjust the volume.