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

Problem is that we are supposed to be trying to replicate a live performance in our listening room.

Not me, I’m definitely not doing this.

A friend creates home theatres and sets in room response flat with pretty darned accurate instrumentation and tells me that he has NEVER - not once, had a client that didn’t crank the gain on the sub channel.

So, to throw cold water on this whole conversation, you don’t want a flat in-room gated response. You want a smooth descending response. You want a flat power response, which is not the same.  This further challenges the main position of the OP that audiophiles want a flat subwoofer. I do not, nor do any experts I know of. A truly flat response is shrill. No one does this. The quasi-anechoic measurements of Stereophile are not what you set your listening position targets to.

Taming bass modes, a smooth integration with the speakers and a descending frequency response are my main priorities.

Best,

E

Is my perception right or wrong gentlemen?

I think you are more or less right, though I come at it differently in my blog post. You almost tie it all together like I have and state that a subwoofer is like another driver in a speaker system, and that to integrate it well to the speaker is as complicated as making a multi-way speaker system.

And this is why my usual advice is to think about exactly what steps you'll need to get to "done."  The easiest answers are preamps and processors with automatic subwoofer configuration, usually a component of room correction, along with appropriate room treatment.

I do believe that the difficulty in integrating a subwoofer is usually under-sold.

You are also perceptive about how big the gap is between home theater and 2 channel in this regard. While 2 channel systems vary greatly, THX specified waaaaay back in the early days of Dolby Pro-Logic, sealed, 80 Hz cabinets for small satellites specifically to address part of this problem. 

Subwoofers are marvelous, glorious tools, but getting to done for the average music lover is just a lot harder than consumers and probably many salespeople realize.  OTOH, let's face it, 90% of those who buy subs aren't actually trained listeners.  They may be perfectly happy with poorly set up subs.  I know I tried to be for a long time with my first M&K V1.

Best,

E

This got me thinking to my times in motion picture sound and looking at big sub cabinets and drivers by JBL and others.

A sub at home typically only covers 2 octaves, 20-80 Hz. It is actually very difficult to produce a speaker which is anechoically flat through 2 octaves with steep roll off after.

Most subs I’ve ever seen have a natural response which is rather hump-shaped. It is the integration with the speaker and the room which provides the smooth and expansive bass people are looking for.

Hi OP,
I am not sure you are in the right place to throw these aspersions. In all of my reading of how A’goners are using and misusing subwoofers I can’t recall a single instance when one asked for a flat subwoofer.

Every post about purchasing a sub here that I can recall (and my memory is not photographic) was about the most musical, followed by the deepest response.

Posts about fixing subwoofer issues certainly involves a lot of discussion about room acoustics and EQ. My thoughts on buying or not buying a subwoofer at all are here:

https://speakermakersjourney.blogspot.com/2020/04/how-to-not-buy-subwoofer.html

I argue that the most important thing to know before buying a sub is how you are going to integrated it well into your system and the room. That's where so much goes wrong.

Best,E