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Discussion Starter · #22 ·
The online manual I found for your receiver says max sub distance is 18 meters/60 ft. Is that the setting? Even allowing for some amp induced delay that seems off.
The issue is that the subs can't be more than 6 meters from the nearest speaker. My surrounds are 1.9m away. That gives a max distance of 7.9m.
 

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Discussion Starter · #23 ·
Hi,

A miniDSP will certainly help, but there are a couple of other things I would also try. Since your front subs are in a cabinet, I can understand that you would be reluctant to move them, even if they didn't already give you the best response where they are. So, let's skip the idea of moving the front subs.

I agree with others that sitting close to the exact center of a square or rectangular space is swimming upstream with respect to bass frequencies. I understand why you can't move the seating area forward, but you might be able to move your L-shaped couch backward by a foot or two without any real harm. I think that you would get used to a little different viewing distance from your screen pretty quickly. You can measure a foot or two behind your current main listening position, just to get an idea of whether moving the couch backward a little would help.

The other thing I might try is to position the rear subwoofer directly behind your MLP. A very nearfield sub is less susceptible to room modes, so it's possible that you will get decent results just from getting it very close to your MLP. You might like some other things that does for you too. With the distances that your three 10" subs are located from your MLP, you are making them work pretty hard even at nominal volume levels.

My final thought concerns the 80Hz null itself. Nulls are deep by definition. The real key though is how wide they are. A narrow null, however deep, may not create an audible difference from a completely flat response. That is because, at those frequencies, each note in an 8-note octave covers several frequencies. (An octave is any doubling in frequency.) Our brains are pretty good at filling-in for missing information as long as the area of cancellation isn't too wide.

Where I am going with this is that people sometimes spend a lot of time chasing an area of cancellation, without knowing whether it actually makes an audible difference or not. That might be something you would want to check-out. There wouldn't be cancellation at that frequency at some other spots in the room, so you could compare the sound to determine just how important that 80Hz null actually is.

Regards,
Mike
I just moved the couch 1 feet forward and tried 2 feet back. No usable change in stereo. Center is fine either way.
 

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View attachment 3121537
Green crossover 110hz. Blue 80hz in stereo.

That picture helps! That isn't really a null. Nulls are more "V' shaped. That is just a very wide area of cancellation and it will definitely be audible (non-audible as a matter of fact). The higher 110Hz crossover seems to fix the problem. Is there a particular reason that you don't want to use a higher crossover? Your bookshelf speakers might actually benefit from a crossover higher than 80Hz.

Regards,
Mike
 

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It doesn't look like a Null to me... it looks more like your L/R speakers can't play much below 100hz. This is backed up by the fact that the Center channel does just fine.

Go into "Pure Direct" mode on your receiver (to turn off all Audyssey and crossovers) and run a sweep on your subwoofer channel and on your Left channel. That way we can see the true performance capability of the speakers. I bet we see pretty signficant roll-off on your L below 100hz.
 
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Discussion Starter · #26 ·
It doesn't look like a Null to me... it looks more like your L/R speakers can't play much below 100hz. This is backed up by the fact that the Center channel does just fine.

Go into "Pure Direct" mode on your receiver (to turn off all Audyssey and crossovers) and run a sweep on your subwoofer channel and on your Left channel. That way we can see the true performance capability of the speakers. I bet we see pretty signficant roll-off on your L below 100hz.
The speakers are rated to 40hz -3db. Original price around $1500 a piece. They are not the problem.

 

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Discussion Starter · #27 ·
That picture helps! That isn't really a null. Nulls are more "V' shaped. That is just a very wide area of cancellation and it will definitely be audible (non-audible as a matter of fact). The higher 110Hz crossover seems to fix the problem. Is there a particular reason that you don't want to use a higher crossover? Your bookshelf speakers might actually benefit from a crossover higher than 80Hz.

Regards,
Mike
I guess the 110hz crossover is the remedy for this. But it would be nice to have them play as intended.
 

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Anthony Grimani’s part 2 presentation on optimal bass in rooms will give you some excellent insight.
 

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The speakers are rated to 40hz -3db. Original price around $1500 a piece. They are not the problem.

I guess the 110hz crossover is the remedy for this. But it would be nice to have them play as intended.

I understand how you feel, but unfortunately we can't really trust manufacturer's specs for this sort of thing. The reality is that those speakers have a single 6.5" driver, in a relatively compact cabinet, which has to handle both mid-bass and mid-range frequencies all the way up to 3,400Hz. That's actually asking quite a lot.

It's no wonder that your 10" woofers, in larger cabinet volumes with more amplifier power, can handle the bass better up to 110Hz. And, remember that all three of your subs combine to play exactly the same bass content, while each one of your front speakers has to stand alone if they try to play 80Hz frequencies at an equal volume with the rest of your listening content. :)

Regards,
Mike
 

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That dip at 80 Hz with an 80 Hz crossover looks exactly like the dip one sees when the speakers and subs are mis-timed relative to each other. I suggest you go into the receiver and add 3' to 4' to the subwoofer Distance settings for both subwoofer outputs. I would not be surprised if that dip goes away completely.

Craig
 

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Discussion Starter · #31 ·
That dip at 80 Hz with an 80 Hz crossover looks exactly like the dip one sees when the speakers and subs are mis-timed relative to each other. I suggest you go into the receiver and add 3' to 4' to the subwoofer Distance settings for both subwoofer outputs. I would not be surprised if that dip goes away completely.

Craig
I can't add more subwoofer distance as i am already at the max (6m from nearest speaker).

A limit set by Audessey. 😔
 

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You would have 2 modes (heightwise fundamental and the lengthwise 3 harmonic) coupling approximately right where you're sitting (approximate because it is opening into the kitchen).
Considering your placement restrictions and having the MLP at one the worst spots possible, you could
a) move the front left sub right behind hugging your couch at the 1/4 width location, i.e. 95cm from left side wall but right behind the couch at the null instead of the front wall.
b) Move the front right sub right behind the couch as well 1/4 length from right side wall, (or a bit closer to mlp if space doesn't permit) . In other words, both your front subs should be right behind the couch, they're not helping you that much sitting up front. That will get rid of the lengthwise harmonic.
c) The place for the back sub is good, but, If you could lift that sub in the back at the same spot, about 3.5 to 4ft to the heightwise null point, that will get rid of the heightwise fundamental. Put that 3rd sub on a stool or something.
These are the approximate best guesses (because of your open layout).
You should be knocking out quite a few problems with this placement and hopefully things sound a whole lot better..
Goodluck.
 

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I can't add more subwoofer distance as i am already at the max (6m from nearest speaker).

A limit set by Audessey. 😔
Dunno why you keep saying, "from nearest speaker."?

I think that might be the problem.
You aren't supposed to measure the sub's distance to the speaker, but to the MLP.
You then take the difference between that and the distance between the MLP and the farthest speaker, then delay whichever is closer.
This will get you in the correct area and REW will take you to the target.

Looking at your floorplan, I reckon your SBL/SBR and FL/FR are the farthest from the MLP and seem to be a similar distance to the MLP.
So, one of those will be your timing baseline, with all others being delayed to synch.
My eyeball sez the subs are of a similar distance from the MLP as the FL/FR/SBL/SBR. So, you should have plenty of delay control for the subs.
 

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Discussion Starter · #34 · (Edited)
Dunno why you keep saying, "from nearest speaker."?

I think that might be the problem.
You aren't supposed to measure the sub's distance to the speaker, but to the MLP.
You then take the difference between that and the distance between the MLP and the farthest speaker, then delay whichever is closer.
This will get you in the correct area and REW will take you to the target.

Looking at your floorplan, I reckon your SBL/SBR and FL/FR are the farthest from the MLP and seem to be a similar distance to the MLP.
So, one of those will be your timing baseline, with all others being delayed to synch.
My eyeball sez the subs are of a similar distance from the MLP as the FL/FR/SBL/SBR. So, you should have plenty of delay control for the subs.
The nearest speakers (surrounds) are at 1.8m. Audessey puts the subwoofers above
8m distance. It then changes the subwoofer distance to 7.8m as >6m difference is not allowed.

I can then decrease the subwoofers distance but not increase.

Does it make sense?

With Atmos I would not want to increase the distance on my surrounds and tops to give room to adjust the subs.

Did try this though. Didn't fix the dip.
 

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What is the actual physical distance of the subs to the listening position?
 

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Audessey puts the subwoofers above 8m distance.
Wow, that's a lot of latency in the subs. Is the subwoofer signal going through some sort of DSP (either an outboard box or something built into the subwoofer amp) before reaching the subs?
 

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Make sure the crossover setting on the sub itself is either off or turned up all the way. If you set it at 80hz and the reciever at 80hz this can cause problems.
 
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Discussion Starter · #39 ·
Wow, that's a lot of latency in the subs. Is the subwoofer signal going through some sort of DSP (either an outboard box or something built into the subwoofer amp) before reaching the subs?
No. PEQ turned off and straight into the Marantz SR7013.
 

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Discussion Starter · #40 · (Edited)
3121970


I did a sub crawl this morning with my SPL. I then moved the front left subwoofer about 7 feet forward between the couch and left wall.

Overall response improved. Pink Neutral X. Purple stereo = dip at 105hz. Good enough I guess 👍🏻
3121969
 

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