Smoothing FR with "lesser" subs? - Page 2 - AVS Forum
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Old 07-17-2014, 10:00 PM
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Oh yea the honey oak version. I am saving them for the day I can build a dedicated theater(hopefully)!

It's amazing that a 30yr old pair of speakers are still some of the most efficient best sounding speakers ever made to date. The draw back is they are huge!!
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Old 07-18-2014, 05:44 AM
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Quote:
Originally Posted by Alan P View Post
Denon 2113ci.

I know I've ran out of headroom when I can hear the PSAs hitting their limiters (sounds like distortion/flapping drivers).



Had a revealing REW session last night....made me sad.

Graphs coming in a bit.
oic.... that's not good. Well, hope u find your fix soon my friend. Could the dip be due to cancellation or phase issues?

Btw, did u happen to have the chance to measure the FRs for single, dual sub setup? it may be useful to measure those too for troubleshooting.
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Old 07-18-2014, 05:45 AM
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Are you sure Audyssey is boosting at 60 instead of lowering everything else?


I guess it doesn't really matter.


What I suggest you try is setting the crossover at 80 or higher (It looks like that's well clear of the null) and put all 4 subs along the couch wall. I think you'll have a problem with placing them along the other 2 walls. You can try putting them behind you, but I think all you'll do is move the null to another frequency.
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Old 07-18-2014, 10:21 PM
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Quote:
Originally Posted by Alan P View Post
Room is about 5000 cu. ft.
Alan,

What if you switched the "couch" to be the primary seating, centered it on the display, and moved it forward to the better listening position, and then placed the chairs on on either side of the couch? That would still look balanced, and it would get you to a much better listening position. In addition, you could shift *your* seat to be in the middle and take full advantage of the sweet spot. (As it is now, both of the primary listening chairs are on either side of the sweet spot, so you have no one sitting in the "best seat in the house."

Craig

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Old 07-19-2014, 09:42 AM
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^I like your thinking craig! That is similar to my config except no chairs. My couch is the primary seat, so on movie night when I am solo, I sit in the middle to take advantage of the sweet spot. Although sitting off to the side is still really good, still not quite as being in the middle for perfect imaging.
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Old 07-20-2014, 08:55 AM
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I tried mixing a small and a box sub once (18" and 10" Velodynes), but ended up blowing the small sub, despite claims about built-in limiting.
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Old 07-21-2014, 12:14 AM
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Can you add a Hsu MBM near field to handle the 60Hz null?
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Old 07-21-2014, 01:35 AM
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Quote:
Originally Posted by Alan P View Post
I found out that I'm sitting directly in the center of a giant 60hz null!

My MLP is currently 5' from the back wall where the picture window is:
Your room is 20 feet long and you're sitting 5 feet from the back wall.

That is the quarter point of room length, right where the second-order length mode nulls:




To find the frequency of the mode, divide the speed of sound by the length of your room.

1130 ÷ 20 = 56.5 Hz



The math worked!

You can either place a one of your subs in that null to prevent it from resonating OR you can move your seating to either 1/3rd or 1/5th of room length to avoid sitting in any nulls:



Notice at 1/5th room length (4 feet from the back wall) none of the modes are nulling or peaking.
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Old 07-21-2014, 10:30 AM - Thread Starter
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Quote:
Originally Posted by craig john View Post
Alan,

What if you switched the "couch" to be the primary seating, centered it on the display, and moved it forward to the better listening position, and then placed the chairs on on either side of the couch? That would still look balanced, and it would get you to a much better listening position. In addition, you could shift *your* seat to be in the middle and take full advantage of the sweet spot. (As it is now, both of the primary listening chairs are on either side of the sweet spot, so you have no one sitting in the "best seat in the house."

Craig
Thanks for the input Craig. I have thought of that setup, and even measured....seating won't fit. I think sdurani has given me some hope though!

Quote:
Originally Posted by sdurani View Post
Your room is 20 feet long and you're sitting 5 feet from the back wall.

That is the quarter point of room length, right where the second-order length mode nulls:




To find the frequency of the mode, divide the speed of sound by the length of your room.

1130 ÷ 20 = 56.5 Hz



The math worked!

You can either place a one of your subs in that null to prevent it from resonating OR you can move your seating to either 1/3rd or 1/5th of room length to avoid sitting in any nulls:



Notice at 1/5th room length (4 feet from the back wall) none of the modes are nulling or peaking.
Hmmm...I didn't measure behind the MLP! Actually, with my recliner reclined, my head is most likely just about 4' from the back wall and this is how I usually listen anyways. I've been measuring from the center of the seat of the recliner (as if I were sitting up straight, which is rare), I need to start taking my own advice.

When you say "place one of your subs in that null", do you mean 5' from the back wall?? Does it matter if it's near the side wall? I could maybe place one on the end of couch nearest the back wall.....I'll give it a shot.
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Old 07-21-2014, 10:41 AM
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Quote:
Originally Posted by Alan P View Post
When you say "place one of your subs in that null", do you mean 5' from the back wall?? Does it matter if it's near the side wall?
Yes, 5 feet from the back wall (or front wall), as long as it is in the null of the second-order length mode (quarter points of room length). It shouldn't matter if it is near a side wall. Also, re-measure from your reclined position (moving the sub might not be necessary).

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