Ideas for formant filter designs

Hi I’m trying to come up with a formant filter design, here’s what I’ve got:

Two bandpass filters sitting on the two formant frequencies for a vowel (as found on wikipedia), but two vowels can be interpolated (creating an “AAUUAAAUAUUAAUAAUU” sound for example).

Now this approach works in general, but the result sounds very thin, like coming from an old radio (which isn’t really surprising given the bandpass implementation)

I tried some things like making the lower filter a resonant LP and the higher a HP, but things didn’t work out.

Do you have any ideas or resources for “strong” formant filters?

Thanks in advance! :slight_smile:

What about two peak filters instead of bandpass filters?

You mean a filter with two peaks? Like a two band EQ? That would be worth trying.
Or do you mean like a LP with two resonant peaks? (I think Will Pirkle had some designs like so.) But yeah, maybe I should drop the whole LP BP HP mentality for this one :smiley:

Well, with two BPs your sound will be very thin as you filter away anything else there is in your signal. Additionally, when you daisy chain your BPs, the order will change the result. With two peak filters, one for the lower formant one for the higher one, both problems are gone.

However, depending on what you want your effect to sound like, also HP/LP with high resonances might give you exactly what you want :slight_smile:

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