Mellow sounding harp

Welcome to the forum. You can try cupping the harp with your hands. The soft tissue can absorb some of the highs. Depending on the mic sometimes getting very close to the mic causes a proximity effect that enhances the low frequencies so try getting on top the mic. You can try a lower key harp or playing on the lower end of your harp. You can EQ it, cut the treble back. Perhaps you are too close to a sensitive mic and overdriving it. And finally, you are correct, you have a lot to do with the tone. More so than the harmonica.

First off hitsware, welcome!!! Great to have you here. It may be just me, but it seems like harps with full cover plates are a bit more mellow, but I would tend to agree with what Rex told you.

Full width covers, as against tabbed covers.

Anyways .... Ordered one of these


Link thingy doesn't seem to work ?

For some reason , when I click on the " Ordered one of these "
It comes back to this page instead of to the link ?

Testing the post

<a href=
"https://smile.amazon.com/Harmonica-kids-Unime-Translucent-
Children/dp/B07H7FY68M/ref=sr_1_37?dchild=1&keywords=
harmonica&qid=1587558735&sr=8-37" target="_blank">
look here</a>

I had bought some kind of similar harmonica as a toy. It wasn't very airtight or responsive, sounded mellow and would have caused frustration. I think that the circulation within the harmonica and especially the separation of the air channels is the main problem.