The Acoustic Pressure Equalizer Ball for 4006A Omnidirectional Microphone is a sphere shaped Acoustic Pressure Equalizer. It comes in three sizes and can be used for the microphone or the stereo kit.

Depending on the size of the Acoustic Pressure Equalizer Ball your microphone will impact your recording differently. The Acoustic Pressure Equalizer Ball comes in three sizes; 30mm, 40mm and 50mm.

The APE30RS, a Ø30 mm sphere, gives a mild modification of your microphone's on-axis and off-axis frequency responses and a slight change in the direction-to-reverberation ratio. This will give your recordings greater presence, nearness and clarity on-axis (especially around 4 kHz).

An on-axis boost, between 2 kHz and 8 kHz, and high-frequency roll-off off-axis, will sometimes help you capture the subtle audible details of both musical instruments and voices.

The APE40RS, a Ø40 mm sphere, offers a more noticeable on-axis boost between 2 kHz and 8 kHz. It also offers stronger off-axis attenuation than the Ø30 mm version. This gives a marked increase in the directivity of your recordings (at 4 kHz, the front-to-back sensitivity ratio is 8 dB). It also decreases the effects of reverberation and off-axis sources.

When using Acoustic Pressure Equalizer, 40 mm Ball, you can modify the spectral characteristic of a source by simply altering the angle of incidence to give a frequency boost, a flat response or attenuation.

The APE50RS, a Ø50 mm sphere, offers a stronger on-axis boost and off-axis attenuation than the smaller APEs (Ø40 mm and Ø30 mm). Its larger dimensions accentuate the on-axis boost at lower frequencies and allow off-axis sources to be strongly attenuated above 1 kHz. This will give your recordings a more intense sensation of source clarity and presence and a marked increase in brightness. It will also extend the effective reach of your microphones.

You will also find that the APE50RS is particular useful for making recordings under reverberant conditions.