Jim Griffin's bipolar mltl

[RH75]

Hello,

New to the diyaudio forum,but not new to diy speaker building,I got interested
in full range speakers.

After reading several posts about Jim's bipolar mltl,I would like to build it.

My only concern is it's bass performance.Several designs based on css fr125s seem
to have quite powerful bass,which might be to much in my 25 square meter listening
room.

I'm pretty confident that Jim's design is very good from what others(FredT's review) say
about it,and he also disigned other winning speakers which got a lot of praise.

I hope that somebody who already built them can comment how the bottom end
of this speaker behaves,and how it can be tamed a little when it gets to much in my
almost square lots of concrete appartment.

Thank you,

Rodney

[GM]

Greets!

Room gain begins in earnest below the longest dimension's (dims) first eigenmode (standing wave), so divide this into ~172.212 to find the theoretical lowest room mode. Odds are it will be below the MLTL's tuning, so any room gain will just extend its LF response, protecting the drivers somewhat from over excursing below it.

Like any low tuned speaker though, the closer you put it to a wall or corner the greater its LF is boosted, so tuning the port lower and/or damping it (AKA 'sticking a sock in it') or maybe even blocking it off if corner loaded is required to get the flattest in-room response.

Bottom line, better to have too much gain and attenuate than too little and boost it IMO since distortion goes down/up respectively.

GM