Indeed: totally normal, when switched on the tv degausses, which is a short buzz, abt 1 sec and than the EHT comes up on the tube whichis the crackle.
When powered down, modern tv's like the Avant discharge the tube/EHT circuit which again gives the crackle.
Old tv's didn't use to do so resulting in a static electricity charge left in the tube for days...
If you don't hear these sounds there would be a reason to worry :)...
PS: if it sounds more like sparks and there's a smell of ozone, that's also no good...(but that doesn't seem to be your case).