The MSGEQ7 Seven Band Graphic Equalizer IC

The seven band graphic equalizer IC is a CMOS chip that divides the audio spectrum into seven bands, 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and 16kHz. The seven frequencies are peak detected and multiplexed to the output to provide a DC representation of the amplitude of each band. The multiplexer is controlled by a reset and a strobe, permitting multiplexor readout with only two pins.

This library implements functions that allow the IC to be controlled and the data read into an internal buffer, from which it can be conveniently accessed.

The Hardware

The hardware implementation is user dependent. Most hardware will follow the typical circuit given in the IC datasheet.

Connections to the Arduino Board

The Arduino interface is implemented with 2 digital outputs and one Analog input whose identifiers are passed through to the class constructor.

The library controls the IC using Reset and Strobe.
The DC Out signal is connected to an analog input to read the value from the IC.

Revision History

May 2024 version 1.2.0

Added internal read delay handling
Updated examples to use new timer
Updated examples for changes in other libraries

Feb 2019 version 1.1.0

Changed return type to uint16_t to match band data.

Apr 2015 version 1.0

First implementation

Copyright

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA