Wayne Parham Messages: 18783 Registered: January 2001
Illuminati (33rd Degree)
That creates a notch around 80Hz to 120Hz from SBIR, which is very common. Most people place speakers about this far from the wall behind them, so the SBIR notch in this frequency range is very common. Scan the internet for in-room response charts and you'll see what I mean.
It's one of the main things that flanking subs are intended to mitigate.