Again, weirdness prevails ... I'm beginning to wonder if there isn't something groing worng with your particular cumbus. Mine cuts through and above a lot of other instruments. Quality can have a lot to do with it; my friend's old, cheap, eBay oud had almost no projection at all, but he recently bought an older, more expertly crafted, 40-year old oud made by some Armernian master oud-maker, and this one really projects (yet, still nowhere as much as my cumbus). The thing that baffles me is, what can possibly go wrong on a cumbus, y'know? I mean, there's not much to it ... metal body, plastic head, neck, strings, nut, bridge ... You're not saying that you're getting any string-buzz or muted, "dead" strings, so it would seem that your neck is in good enough shape and your bridge action and nut height are close enough to where they need to be. Could a VERY old drumhead create a softer volume? I just don't know ...

I have about 4 cumbus...
They are always pretty loud. Especially compared to an oud and are perfect for playing with a couple of doumbek players.

The older.. older ones are kind of not good.. but the new new ones are great either.

Of my cumbus...

Aluminum - Good volume
Wood (yes wooden). It's got a decent volume, not as loud as metal. Sound is more round and even and less agressive, but still sounds like a cumbus.
Copper - Haven't seen many of these. I have one and it's LOUD. Really LOUD... surprisingly loud :)

-Carmine

By the way.. I have cumbus heads and bridges I could sell/mail to you.

If you have an old paper-ish sort of head. maybe it's just worn out.

Email me directly: carmine@carmine.com

I don't log on tribe much anymore.

-Carmine