That's cool and everything and I have some knowledge in the field. Too technical for this experiment.
For the average consumer, the furnace
is too noisy. Suburban didn't want to entertain, to me, that there is an industry problem. Why should they since there is only one other competitor.
However, they did offer to replace mine with a new Q-series but I don't want to trade a Pink Lady for a Granny Smith.
It doesn't matter what the numbers read on the (my) meter. (They) will be the baseline. I was willing to mail my decibel meter to Suburban so the numbers would at least be coming from the original source. I had no reply to that query. So much for product knowledge on their end.
They did state that the internals are different on the new Q series and the blower/motor assembly is not a direct swap into the preceding units.
There are other furnaces. The boyz from Propex did sound level readings on YouTube due to the large volume of inquiring questions. Espar. Webasto. What about any of the house style direct vent , such as Empire DV-210 or Williams, can be installed. They don't require electric but can be fitted with an optional 110v blower.
My hat is off to the OP. He started to do something that many of us want to but ended up stopping.
I'm sure that the industry is heeding to the complaints. There may be a time in the future when we can all get a warm good night sleep while listening to the crickets and frogs.
See ya 'round the campfire.