McBoost™ Development

At Radial, we are constantly being tasked to come up with solutions to problems that audio engineers face each and every day. One such problem is elevating the signal level of a low output microphone so it can perform better with a typical mixing console.

The problem is that most mic preamps and mixing desks are only designed to boost the signal by about 50 to 60dB. Although this is perfectly suitable when working with most dynamic and condenser mics, there are several instances where more gain is necessary:

  • Capturing low output sources with a dynamic mic
    When recording low output instruments, condenser mics are usually the common denominator. However, many engineers find that dynamic mics bestow a certain character and quality that can often be beneficial on certain instruments. Dynamics also tend to be more durable which makes them a better choice in live settings. The McBoost will increase the 'reach' of a dynamic mic to where it will become more condenser-like. Since the McBoost will also improve the signal-to-noise, using it for long runs in the studio can be very beneficial.
  • Working with older low-output ribbon mics
    Most older ribbon microphones produce a very low output that is not suitable for a typical mic preamp or mixer. To bring them up to a suitable level, this requires either using a specially designed preamp or a mic signal driver like the McBoost. With a McBoost, you can combine your favorite vintage ribbon mic with your favorite mic preamp or mixer.
  • Driving long cables in broadcast environments
    Broadcast engineers will tell you that each and every day presents a new challenge. Often times, this can involve doing an interview or capturing a source that may be thousands of meters away from the recording system. For instance, running mic cables down to a football field, across a golf course or into a hockey arena. Placing a McBoost near the mic (within 15 meters) will increase the signal level which, in turn, will improve the signal-to-noise and fidelity.

Changing the load

We began messing around with impedance settings back in 2001 when we introduced the Radial JD7 Injector™. We made even more discoveries when we launched the PZ-Pre™ and PZ-DI™. In both cases, we were working with guitars with either magnetic or piezo electric transducers and we found that changing the impedance could dramatically improve the sound of the source.

With the McBoost, we discovered that inductive sources such as dynamic microphones are particularly sensitive to the input impedance and as a rule, the input is usually higher than the source. For instance, most dynamic mics have a characteristic impedance of between 200 and 600 Ohms while the input of a mixing desk is often around 10k Ohms. Depending on the microphone design, lowering the input impedance may roll off the bottom end and you may also affect the output level. On the other hand, when you elevate the impedance, you will likely bring out more of the high end. Unfortunately, it is impossible to determine the final outcome as each microphone will react differently. It is a matter of listening to the settings to find what works best for you. Since most ribbon microphones employ a transformer at their output, they will behave similarly.

At the end of the day, the McBoost is a simple plug and play device that does exactly what it is supposed to do... elevate the output of your mic without adding color or distortion.