Support bar on converter
 

Hello,
I have a 2005 Honda Civic hybrid 1.3L and I just replaced both converters because I purchased it recently and it had a code po420. And also because they are original to the vehicle and the car had 167, 160 miles on it. Anyway now when I accelerate it has a low acoustic sound when I first accelerate in drive and it slowly tapers off and goes away around 25 mph. In park it makes no such noise even if you accelerate. I used all new bolts and springs on the converter and torqued the bolts to spec. Not sure what could be causing this?