Exhaust replacement

[banpei]

I measured the amount of noise my car makes using my phone 50cm diagonally from the exhaust.

It produces 85dB during cold start (1600rpm) and 84dB when warmed up (950rpm).
I found there wasn't much difference between these two, which surprised me. I revved it up, but my phone can't register more than 88dB. I did three trials and at about 2500rpm it reached 88dB.
In case you're wondering about the high idle: aircon.

When I compare that to this video, there is a lot more variation between idle and 2500 rpm:

That's 67dB at idle versus 85dB at 2500rpm on the Martelius exhaust. I'm wondering if my rear muffler is doing anything at all...