2 low end subs or 1 semi-low end sub

[Howard]

Sure, you can place two subs so that they interact perfectly at 40hz and you have no dead spots. What happens at 53hz? or 71hz? You have all new and exciting dead spots and hot spots in your room.

If you want to SEE it happen, fill a room with smoke and run two subs at the same frequency. You'll literally see the high pressure spots versus the low pressure spots. Or click here for an applet showing a pair of oscillating point sources in a box: http://www.falstad.com/wavebox/

My point is that for ~95% of installations you're not going to be able to perfectly place the listener OR the subs, and you're introducing a second set of potential issues. With a single sub you just have to worry about boundary cancellation, but with two subs you introduce phase cancellation, doubling the complexity of the equation.

Edit to add: check out Bill Fitzmaurice's post on the topic (for live sound reinforcement) here: http://billfitzmaurice.info/forum/viewtopic.php?f=1&t=398

All this is well and good in an open field, but an open field a room is not. Let's see some measurements below 80Hz in an average room for varying numbers of subs.

 

[klocwerk]

All this is well and good in an open field, but an open field a room is not. Let's see some measurements below 80Hz in an average room for varying numbers of subs.

Yes, I'm coming from a live sound theory background, but the concepts are directly applicable to in-house HT with the additional factors of room gain and boundary cancellation.

Knock yourself out, let us know what you find.

 

[YOyoYOhowsDAjello]

Yes, I'm coming from a live sound theory background, but the concepts are directly applicable to in-house HT with the additional factors of room gain and boundary cancellation.

Knock yourself out, let us know what you find.

So this isn't good enough?

http://www.harman.com/EN-US/OurCompany/Technologyleadership/Documents/White Papers/multsubs.pdf

 

[Howard]

Yes, I'm coming from a live sound theory background, but the concepts are directly applicable to in-house HT with the additional factors of room gain and boundary cancellation.

Knock yourself out, let us know what you find.

What the hell? I never said I was looking for anything - you guys are the ones with points to prove, not me.