Using bass reflex to combat poor room acoustics

[johnc]

I recently bought a pair of Beyma 12P80Nd drivers for my first HE build.

Sensitivity Frequency range Voice coil diameter BL factor Moving mass Voice coil length Air gap height X damage (peak to peak) Resonant frequency, fs Mechanical Quality Factor, Qms Electrical Quality Factor, Qes Total Quality Factor, Qts Equivalent Air Volume to Cms, Vas Efficiency, ho (%) Net weight

101 dB 2.83v @ 1m @ 2?   25 - 4000 Hz   100 mm. 4 in.   23.1 N / A   56g   20 mm   12 mm   52 mm   45 Hz   6.6   0.15   0.15   95.7 l   5.4   5.6 kg

I am still deciding what HF drivers to get but I had some time to fiddle this weekend.
Some of you know I'm not a huge fan of BR or any unnecessary resonance for that matter.
But I do stuff around with BR occasionally.
Below is a report after my general stuffings around.

I have been experimenting with an "extreme" bass reflex design for other purposes.
I use "extreme" for want of a better word. One of the things about a low Qes driver is that excursion is not particularly sympathetic to bass reflex influences.
Graphs below are SPL, Excursion and Port air speed. The port is 125mm in diameter.

For some background, the graphs below illustrate the problem with my lounge. I took these measurements a few years ago - I can't remember what speaker I was measuring. The first is the response with the mic close to the speaker. The second is with the mic approx 1.5m from the same speaker. Here is a pic of the speaker showing the convenient port on the side. I'm not going to bother with more graphs but the sharp BR resonance has certainly smoothed out the overall frequency response. Does anyone else combat challenging rooms this way?

 

[Timber_MG]