Auralex Acoustics Aural-Xpanders Acoustic Micphone Baffle Set AuralXpanders give the recording engineer a high degree of control by providing the capability to filter the undesirable external overtones that tend to push the engineer to over-process on the back-end during the mixing stage. AuralXpanders offer the recording engineer a means of tonal control and passive filtering before the sound ever hits the signal path and before ever reaching for a knob or booting-up a plug-in. AuralXpanders give the recording engineer a high degree of control by providing the capability to filter the undesirable overtones AuralXpanders offer the recording engineer a means of tonal control and passive filtering before the sound ever hits the signal path