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Graphic Equalizer Display Filter - MSGEQ7
Replacement:COM-10468. This is the same IC in an RoHS compliant package. This page is for reference only.
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. No external components are needed to select the filter responses. Only an off chip resistor and capacitor are needed to select the on chip clock oscillator frequency. The filter center frequencies track this frequency.
Other than coupling and decoupling capacitors, no other external components are needed. The chip supply can be between 2.7 and 5.5 volts with 5 volts providing the best performance. The device has very low quiescent current (less than 1ma typical) for portable audio devices. the multiplexer is controlled by a reset and a strobe, permitting multiplexer readout with only two pins. The multiplexer readout rate also controls the decay time (10% decay per read), so no external pins are needed for this function.
- Low Power Consumption
- Only Two External Components
- On Chip Ground Reference
- Switched - Capacitor Filters
- 3.3 or 5 Volts Operation
- 20 dB of Gain
- On Chip Oscillator
- Output Multiplexer
- Variable Decay Time
- 8 Pin DIP Package
Graphic Equalizer Display Filter - MSGEQ7 Product Help and Resources
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It is not completely your fault since the manufacture's data sheet calls it such but, this is NOT and equalizer. It provides no ability to alter the frequency domain characteristics of the signal, it does no equalization. See http://en.wikipedia.org/wiki/Equalization
This would probably be more correctly described as an audio frequency spectrum analyzer.
I was a bit confused when I first read the description because I could not figure out if this actually provided some type of adjustable equalization or just spectral analysis for display. After reading that data sheet it is the latter. It is a neat chip but it is not an equalizer.
-Eric
I suppose the "Display Filter" part of the title should have been better emphasized in the description to help reduce confusion. Still though, using the words "Graphic Equalizer" first in the title and then starting the data sheet description with "The seven band graphic equalizer IC" is misleading.
-Eric
Yes, it is a filter for display for a graphic EQ. It is not an audio processor. It is primarily used for graphic equalizer displays, therefore, it's a graphic EQ display filter.
The link to the MSGEQ7 tutorial created by J Skoba is broken, but I have posted a copy on my site at:
http://nuewire.com/info-archive/msgeq7-by-j-skoba/
Got one of these for Christmas, very excited! I read the spec sheet twice, and I may be blind, but... what are the typical and max inputs of AUDIO_IN supposed to be? I see a reference to .1V and .3V peak-to-peak, so I assume those are "safe" values... but no idea how close to the hairy edge those values are. Anyone measured?
I just got this myself, and was going over the data sheet. From what I understand the chip takes the Peak-Peak voltage and applies a gain to the individual frequencies to to supply an output that is somewhere from 0V to VDD.
That said, the minimum gain is 20dB and the maximum is 24dB with a typical gain of 22dB. This translates to a maximum gain x15.85, minimum of x10, and a typical gain of x12.59. (dB = 20*log(UnitOfMeasure))
So if 5V=VDD, then an input Voltage of 0.315V or below would be appropriate. But in reality it would be hard to say, since the gains are applied to the individual frequencies and not the entire input signal. So different frequencies will have different gains. I may do some testing to get better numbers.
I wouldn't recommend taking a shortcut and trying to use a single chip to analyze two separate audio channels. The decay is built-in and drops 10% for each read cycle.
You'll get bogus readout if one channel doesn't match up with the other (which is why you'd want to analyze in stereo in the first place).
It's been out of stock for a while now. Will it ever come back?
Any sense of when these might be back in stock? Awesome little chip.
Looks like these folks have some interesting parts. Any chance of expanding your line of them? I'd be especially interested in the Single Chip Spectrum Analyzer (similar to this chip but with six 1/6th octave filters) and the 15 Hz to 64 kHz sine source.
:D YAY! I suggested this a few weeks ago, and I'm so glad they decided to start carrying this.
i got one of these from the manufacturer a month ago. works great for audio reactive projects. Im using a
BOB-09964 (NEW electret board) that goes into this chip, that goes into an el sequencer board. I am only reading the 63 hz band so my project is BASS reactive. it rocks to the beat.
i am having one problem - paired with the SFE
BOB-09964 mic board, the combined gain of the electret board and the msgeq7 is a little too much. can someone comment on how to reduce the gain of the pair just a little??
oh, and please make a breakout board. i made one by hand and its UGLY.
Here's a small writeup on using this chip with an Arduino:
http://skoba.no-ip.org/msgeq7/
Multiplexor should be multiplexer.
Fixed. Don't trust datasheets.