Low voice and MFCC frequency

I’m a little confused about the frequency setting in the MFCC
My vocal range is quite low C#2 D2 or 70Hz or there abouts is the lowest note my voice go naturally.
The default low is 200 if I use this value is my voice getting filtered out.
I’ve tried changing it and it’s not really clear from the results.

Hi Greg,

The default value should still work well as the MFCC transformation will also pick up the harmonics in higher frequencies.
Are you having issues with performances? Feel free to share your project ID as well.


@greg_dickson So the low frequency / high frequency are not a filter that you can tune that way, but rather the lowest band edge of mel filters and the highest band edge of mel filters, so there’s already some processing going on, which indeed might filter out frequencies that the block thinks are not used in speech so much.

Spectrogram block gives you more clarity for this (but probably want to downsample to reduce no. of frequency bands) - or use MFE block and you get better visibility in what the block makes of your voice.

Thanks heaps guys.
my project id is greg_dickson-project-1
even though this is a personal project and fairly limited I have made it public.

What made me curious about this I was collecting live results. I uploaded the correct recording into the base and then false positives into unknown. However the early results seemed to perform better than those with the extra data.
I did try setting the MFCC low frequency to 69 and the filter number up to 32 and was able to get the base accuracy to 95 % but the trst didn’t improve much. I have changed so many things and not kept notes so it’s a bit hard to really be clear on what I did and the effects.

It would be nice to be able to have a sort of history system in the whole process so a user could make direct clear comparisons.
ie list of setting = training results and test results.

Anyway Thanks I’ll keep playing and give my ideas and feedback as I can.

I just added the MFE as well and that helped a little is adding MFCC and MFE a good idea? Sort of just playing now :slight_smile:

Oh by the way I love how well the C++ code compiles and re-compiles so cleanly each time I deploy a new version. Well done guys.