Sunday, November 22, 2015

Compensating for the 2 proximity effects on a Shure SM58

There are 2 proximity effects (when mic is close to mouth), one the increases bass  and the other that increases treble called the obstacle effect


Natural sound from vocal cords to brain of listener for a Mexico made  SM58 next to mouth were obtained as follows:


SM58 was shunt with 19.5mH !  i.e. low cut at 1.6KHz and 15nF shunt to the Pleiades V4 (EF183 pre preamp with 4 AA batteries) output to reduce treble boost, sibilants, saliva noise (sometimes desirable). Added advantage is the reduction of any hiss left and rounding waveform curves should instantaneous peak limiting  occurs at the electron tube, thereby preserving subjective volume due to natural harmonics produced while objectively limiting the signal.


Signal path used:


Voice - SM58 - Pleiades 1:7 input transformer, 19.5mH primary L - V4 (+ve bias from plate to grid) - 15nF across output - Realistic Disco mixer mic in - pad before headphones - Sennheiser HD560 - ears - brain


No comments:

Post a Comment