Instrument Reflexion Filter (IRF)
The Instrument Reflexion Filter is designed on the same principles as its bigger brother the Reflexion Filter.
It forms a small curved wall of punched Aluminium, with 3 layers of polyesther fibreboard separated with air gaps, which helps reduce room ambience and isolates the mic from ambient noise.
The IRF has a hole punched through it to allow a pencil mic, or SM57 etc to be fixed through it, especially useful when close micing drums (to help with track separation) or overhead micing.
The IRF is ideal for use with pianos, drums and wind instruments, whereas the RF is used for vocals and guitars.