Better low frequency coverage?

It is really a simple (& no brainer) solution if you think your tweeters are inadequate at lower frequencies. Just compliment it with a normal speaker - just as in any loud speaker box.

This is the set-up at one of my bird houses. Though I think it may not be necessary, I did it a while ago just to see if it works better. If the tweeter performance is characterized, it will take out the guess work.
















The paper cone speaker should be sheltered from weather with an aluminum screen. (I'll update with a picture next).

So there is no need for alarm when people posed question "Your birds may not hear the low frequencies". The dummy approach is to cover low end with a speaker.

We should actually counter-ask "What low frequencies?" When we know truly the frequencies of the bird calls only then we know the required bandwidth of the tweeter. Otherwise it is simply guesswork.