Noise 1980 240D help ID

[Treeman]

I have a new noise that only happens when I am moving and starts at about 10mph in any gear.

I have searched the forum for descriptions of Noises others have heard or hear.
This is not a grind, whistle or growl or thump or squeal.

It sounds like what you hear when you blow over the top of a large bottle and it's loud and gets louder the faster you go, until it peaks at about 30mph.
Does it with clutch engaged or disengaged.
Depressing brakes does not alter the noise, turning the steering wheel changes nothing.

It sounds like the noise is coming from under the gearshift of the manual transmission.
But I'm starting to think it may be coming more to the passenger side front wheel or somewhere in between.

I am kinda scared to keep driving the car to try to pinpoint the noise in fear I will tear something up.
My wrenching bud seems to think that somehow we have reverse and forward gears partially engaged at the same time.
But it seems to me this would be close to impossible because the gears are tight, either engaged or not ie there is no slop there.

Hope the noise description helps.
If it will help I will record the noise and post it.
You will have no problem hearing what I have tried to describe.

Appreciate the help in advance.