Mine is always louder when I am sitting on the couch. I have been diagnosed with PT. When I am standing it goes away. But I also get the heartbeat sound too. I think it has to do with blood flow, or arteries and kinked veins. If blood is not flowing smooth there is turbulence which makes the noise. Neck issues can cause the noise and spine. I may consider seeing a chiropractor. If I press my cheek it also makes the noise change. I posted an article in PT forum. Some T patients had shunts put in clogged arteries and veins. Their T was gone in two days.