John and Mac,

Thank you very much for your suggestions.

I can hear the shhh noise through the USB adapter's built-in headphone monitor. When the mic gain on the adapter is turned all the way down, there is the one green bar in the VU meter, and the shhh sound is reduced to a higher pitched soft sounding whistle. As the mic gain is turned up (whereby singing would hit the yellow and red levels) the sound turns into a broader shh sound with that high pitch still there but more in the background.

As an aside, the adapter has a monitor dial to allow one to hear sound through RealBand and the mic input at the same time, the balance of which can be adjusted. I've used both an in-ear headphone and a regular headphone to ensure no spillage from the instrumental tracks - but anyway this shhh noise is happening even when the other tracks are not playing or I am not singing/speaking into the mic and the environmental noise is silent.

On the basis that either the adapter, or the supplied cable used to connect the adapter to the USB port, could be defective, I've now contacted both the dealer and the UK Shure distributor, and await a response.

I'm dying to record vocals using the tracks I've created via the splendid BIAB (and the Shure mic itself is wonderful too). So if this issue isn't solved, perhaps I need to move to something like the ART USB Dual Pre Two-Channel Preamplifier/Computer Interface (whose advertising claims it is "low noise")? Although the cost for it here in the UK is a big ouch.

Anyway, thanks again and I appreciate your help.

Zoë