Smart microphones and mixers

When talking about microphones or intelligent mixers, reference is not being made to anything other than the capacity provided by some digital systems and controls so that these equipment can detect specific characteristics, typical of some sounds and frequencies, and allow each of these devices to be used in more than one application. But what does this mean?

Simply, within the design of the electronics of these microphones and sound mixers, DSP (Digital Signal Processing) technology is included. Actually, it's not that these devices are smart. They only have some options that allow the use for different recording and mixing situations, and control the recording conditions. This does not mean that because they have many more alternatives of use you can do with them all the work required. These systems also have some limitations.

To understand a little about the concept of intelligence applied to the acquisition of sound by means of a microphone and to the work of mixing for the same purpose or for the work of the same in the studio, let's remember the proposal of Audio-technica with its AT895 system, and a brief overview of Shure's IntelliMix technology.

The AT895 system incorporates a microphone controller composed of a series of five elements that provides the possibility of adapting in a directional way during the acquisition or recording of sound.

Using Audio-technica's proprietary DeltaBeam technology, this system manipulates and filters the output of the series of elements by acoustic, analog and digital means. This process improves the capture of the sound source from a specific direction relative to unwanted noise or interference from the environment, providing a cancellation of up to 80dB. Ambient interference, mechanical noise, wind noise, proximity effect, are automatically reduced. And most importantly, unlike the attempts made through other devices, the audio quality remains natural and with a very wide bandwidth.

The behavior and advantages offered by this system can be made evident when the results are compared by means of a sound capture test, under similar conditions, with a conventional Shotgun type microphone.

Shure's IntelliMix technology is an operating concept that underpins the company's automatic mixers to offer mixing work by combining three functions separately:

This function makes it possible to distinguish between constant ambient noise (such as heating systems and air conditioners) and changing sound (such as the human voice) for each input channel. It continuously adjusts threshold activation so that only voice levels higher than ambient sound can activate a channel. It is a great advantage over proportional gain algorithms that is achieved by reducing background noises without having to add more gain to the speaker who produces louder sounds. Often, it is this one who needs the least profit.

The MaxBus function ensures that only one microphone is activated by each of the sound sources. Each speaker activates a single channel, even if multiple microphones receive the signal from their voice. It is a concrete application of the sound capture technique when the situation requires the simultaneous use of more than one microphone. It gives way to the sound that comes from the voice of one of the speakers while the other channels remain closed. This prevents the filtration of sound through the other microphones and can isolate and control, to some degree, the capture of sound from the environment.

The last of the functions offered by IntelliMix technology, it is responsible for keeping the microphone open recently until another of the microphones is activated. Without this feature, a pause in conversation might sound as if the audio signal has been lost. This ensures that the background sound signal is present all the time.

The three functions we have just described are part of Shure's technological development called IntelliMix. These characteristics are found only in the automatic mixers of this manufacturer. One model designed for production applications is the FP410 four-channel portable mixer.

These two technologies, Audio-technica's DeltaBeam and Shure's IntelliMix , are two examples of "smart" applications for sound signal picking up in field audiovisual production.