Why do you guys pursue a flat frequency response when you buy a subwoofer?

Why do you ask?

Why buy a sub from a manufacturer who can't even get a flat frequency response when so many can?  Of course there are room issues that need attention but you might as well start with a good fundamental frequency response.  

The minute you put that flat sub in your room and take some measurements, it is anything but flat (it's a rollercoaster with all kinds of peaks/nulls etc, EQ to the rescue).....So, why do you dudes continue to look for the flat line?

Good question. This dude used to think like that, until he started reading the other guy, aka Duke, aka Audiokinesis, and that guy led the dude to reading some other guys, none of whom think like most dudes but instead actually studied the problem. All this reading led to actually for the first time understanding the problem, which yes most dudes do get wrong but this guy now does not.

What the real sub guys know that the dudes do not is what Duke alludes to above as "an interesting challenge".

You are right deep, put one sub in a room and you get peaks and valleys all over the place. Move the sub, peaks and valleys move but are all still there. You move the one sub around endlessly. Been there. Done that.

So, to review, one sub no matter where you put it produces lumpy bass. Moving the sub only moves the lumps, but never gets rid of them. The solution, which you can only shake your head at the brilliant simplicity of it all, is more subs.

With more subs each sub has to put out much less volume. So the lumps get smaller- and there are more of them. Which when you get enough small lumps turns out the result is pretty smooth. This brilliant idea of using lots of bass sources distributed around the room is called a distributed bass array or DBA.

Duke the speaker guy makes em. He calls his version the Swarm. Mine is based on his. https://systems.audiogon.com/systems/8367  Notice there's three different types of subs- 2 ported, 2 sealed, 1 isobaric. There's other guys here with DIY DBA, and other guys using the Swarm. The one thing all us guys have in common is we love our smooth, articulate, deep and totally awesome bass.

That and, we wish more guys knew about it, and we could all be less like the other dudes.

" Imo the first issue can be addressed by designing the subwoofer to have a native frequency response which slopes gently downwards by the approximate inverse of "typical" room gain, or 3 about dB per octave. I'm not saying this is the only way of addressing this issue, but imo it results in a reasonably good starting point.

The second issue (rollercoaster in-room response) presents an interesting challenge. Opinions vary on how to address it."

Duke, 
Can you name the popular opinions among sub manufacturers on how they think it should be addressed? Of course, more subs a.k.a an array of 4, 8 or 16 is great for business. But, are there other opinions out there?

I currently have Rythmiks (room1) and HSUs (room2) at home and a BIC PL 200 II in my shop. The BIC is not flat and i saw some clowns arguing in a forum that the BIC is very very bad because of the peak in its spec! However, this budget BIC actually sounds pretty freaking good to me and i use it largely for music in my shop. As far as the manufacturers coming up with a flat response (Rythmiks, HSUs, SVS, etc), Is it just a "statement" that they are competent enough to come up with a flat response? (though it means jack sht after it goes in the room) 

A careful look at the dimensions of your various rooms may tell you quite a bit about why the shop sounds so good.

obviously Danny at Rhythmic , Duke at AudioKenisis, and others know what they are doing relative to room nodes, room gain, and designing for flat response, some w adjustable phase. My favorite designer is Vandersteen’s with 11 bands of EQ below 120 HZ, variable count our, EQ centers on common room nodes. Contrary to Miller’s myth, many sub designers are very aware of Earl Geddes seminal work on multiple subs to cancel out constructive and destructive interference ( Duke you really should look at the wave photo I emailed you long ago ), I will post it in my virtual system page... perfect example of constructive/destructive interference), Many ( but thankful not all ) customers don’t want a forest of subwoofers in the room. RV power factor corrects his supplied amp which also has feed forward control - others use servos, etc. point is there are some fantastic subs out there.
one way to quickly judge sub integration with mains and response and pitch definition is by listening to well recorded scaling acoustic bass - Ray Brown Soular energy is fantastic for this :-)
enjoy your BIC and other subs OP, enjoy the music !!!!