Subs in rooms, some data points

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So you've sim'ed and built the perfect sub. Now you bring it to your room.

Below are two REW charts comparing woofer outputs for two units, L and R. In each chart, the upper curve is the measurement at like 5 inches from the driver and the upper curve (shifted so that the two lower bands sort of match) is with the mic where my head is located when listening.

Each pair has the same EQ which was devised for a nice response at my seat and a bit different L and R. At the seat, the approximately "5 dB + and -" band ends around 25 Hz.

While not much can be said about each curve, it is the room acoustics comparison that is interesting. At the seat compared to up close, the L sub changes 15 dB at 53 Hz and 12 at 125. (Remember, they have the same EQ and that EQ is intended to make the seat curve look good.)

The R sub changes 20 dB at 60 Hz and 10 at 125, and looks different from L in other ways too.

You are only part-way there when you bring your perfect sub into your music room. Subs have to be tuned to the room.

B.
PS. L is a modified 15-inch 1960 driver in 5 cu ft (140 L) sealed box. R is a 1955 AR-1, 1.4 cu ft sealed box
 

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Assuming the sub is "perfect" it would have been designed to have a frequency response as close as possible to the inverse of the room gain curve so that it was as flat as possible at the listening position without needing any eq.

What you are showing is a total lack of thinking about the room in the simulation phase, therefore the sim is bad and the sub is obviously far from perfect.

Hornresp makes it easy to measure the room and incorporate the room gain curve right into the simulation.

All you are showing is the room gain curve can make your frequency response change dramatically. Everyone knows this. There isn't anyone that doesn't know this. I'm not sure why you think people don't know this.

It's easy enough to use simulation tools to incorporate the room response into the simulation so you won't have any surprises and will get the flattest response possible. This is not practical unless it's a permanent installation (or at least semi permanent) but if that's what you want to do it's easy enough to do.

If you were aware of what simulators can do you would never present either of these subs as "perfect". They both use antique drivers without enough xmax to even call a sub driver and both designs completely ignore the room. They are far from perfect.
 
Ben, any chance you can post those graphs with a little more resolution on the dB scale?

10dB per division smooths everthing out.
As you request, here's L again but with 5 dB per division. But what are you curious about?

Seems to me that smoothing, here it is 1/12, would be of greater interest. I explored changing smoothing from my standard but did not find it added any information.

Yesterday, I was checking the bias on my ESL panels (9500 volts). Anybody knows with a Behringer DSP you can do FR on each speaker by pressing a button or two. So I just ran all my speakers one by one. And then.... figured might as well post the data points as an antidote to the mountain of theoretical sim talk here. My modest purpose is simply to point out that you are only part-way done when you put the box in place. The room has overwhelming influence that can't be anticipated.

Thank you Jerryo. He's been stalking me at DIYaudio for years. Every so often his vitriolic impulses get out of hand.

B.
 

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Good god man, there is no need to be quite so harsh on ‘bentoronto’. Be nice for crying out loud and make helpful suggestions......don’t just rip into him.

.... figured might as well post the data points as an antidote to the mountain of theoretical sim talk here. My modest purpose is simply to point out that you are only part-way done when you put the box in place. The room has overwhelming influence that can't be anticipated.

I've been making helpful suggestions in the form of trying to teach him something for years, and yet this is where we still stand.

Simulators were never meant to simulate the room influence. Ben seems to absolutely detest this fact. BUT Hornresp will allow you to measure the room gain curve and use it as a baseline which means you can include it in the sim.

What Ben is trying to show here is that simulators are useless because when you put a sub in a room the response changes. I've been talking to Ben about this for years but since he won't actually download and attempt to use a simulator he's never going to learn what they can actually do.

Thank you Jerryo. He's been stalking me at DIYaudio for years. Every so often his vitriolic impulses get out of hand.

B.

I don't stalk anyone. I don't step foot outside the subwoofer subforum. You know this is where I am and you know that if you post nonsense here I'm going to clean it up.
 
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