I just realized that I am unable to have a loop length of less than 480 ticks (which is a 1/8th note on a 4/4 meter). Even if I set snap off and choose a much smaller strip of the audio clip and click "Set Loop Points to Selection", it still selects a 480 tick region covering either side of the region I select. 
 
Is there a setting somewhere which I can modify to enable me to select a smaller loop region than 480 ticks ?

Not in front of my DAW right now but, yes, I believe 480 ticks is the minimum, and there's no altering it. It's pretty hard to do anything useful with less. What's the goal?

brundlefly
Not in front of my DAW right now but, yes, I believe 480 ticks is the minimum, and there's no altering it. It's pretty hard to do anything useful with less. What's the goal?

Yeah I agree normally one would never need to loop a clip so small. Its just that I was trying to use the frequency profiler function of Cockos' ReaFIR to get the exact frequency profile of a nagging but extremely short click in the middle of an audio clip. If the loop is longer than the exact click region, then it would profile the rest of the region as well which I didn't want.
 
Anyways, I ended up split separating the click region and taking it to a separate track so that though the loop region was longer, the region on either side of the click was blank. That way I would get the profile of only the click. Turned out a simple workaround 
 

That works. Or you could do a temporary partial mute of the audio clip in situ by dragging with the Mute tool in the region after the transient. Dragging in the bottom half mutes (muted section of waveform becomes a dotted outline), and then either Undo, or drag in the top half to unmute when you're done.

brundlefly
That works. Or you could do a temporary partial mute of the audio clip in situ by dragging with the Mute tool in the region after the transient. Dragging in the bottom half mutes (muted section of waveform becomes a dotted outline), and then either Undo, or drag in the top half to unmute when you're done.

That helps too. Thanks.
It also struck me that I could always use an effect plugin on a clip instead of the track. That way, in any case, the effect of the plugin would only be on the clip which I can split out, thereby not affecting anything else in the loop region, however big the region may be.