Compression sound from dash

[E!]

On my 92 s-10 blazer there is a constant compression sound coming from the dash .

It sounds like it is coming from the area where the speedometer and gauges are .

I'm stumped ??? can I get some suggestions on what this might be  

[bowtie_pasta]

Compression sound?  Never heard of that.  Can you describe differently?

[E!]

Compression sound?  Never heard of that.  Can you describe differently?

It is sort of a steady hiss coming from the area of the dash around where all my gauges are .

I just got finished with a 3000 mile plus round trip to Phoenix and did not have any problems with it although it did not go away .