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Discussion Starter · #1 ·
I have very limited space up front and currently have it in the backside of the room by where my wife and I sit. The bass is just annoying, you can tell by ear exactly where it's coming from and at times you can hear low vocals which just sounds terrible.


Up front, I have an end table that would fit my sub under it, but the Sub would have to sit on the bottom wooden level about 4" off the ground. I would be able to anchor it to the table, and eliminate movement and vibration noises.


Is it a must to have it on the floor, how much sound/vibration will I loose?


Maybe I'll just give it a try when I get a chance, any suggestions if its worth it.
 

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Since you're able to localize the sub and hear vocals, it's possible you've got your crossover set too high. If you've got decent bookshelf speakers (or larger speakers than that), you should try dropping your crossover to 80Hz.


If you've got satellite speakers, you may not be able to lower the crossover much (if at all), so do try re-locating the sub to the front. You'll only know once you put it there whether that location will result in good overall output and extension at your primary listening position. The 4" lift shouldn't make a difference.
 

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Quote:
Originally Posted by dmb12679  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24509877


The bass is just annoying, you can tell by ear exactly where it's coming from and at times you can hear low vocals which just sounds terrible.
That indicates the crossover is too high. When it's correct you can't tell where the sub is and the directional cues will come from the mains. The bass will seem to come from the mains no matter where the sub is.
Quote:
Is it a must to have it on the floor
It's not. For full acoustic coupling with the floor it must be less than 1/4 wavelength above it. At 80Hz that's 3.5 feet.
 

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Discussion Starter · #4 ·
I will drop the crossover to 80 on the receiver and sub, if that doesn't work I will try and make the move to the front. Right now it is just pinched up against the couch next to the recliner where we sit. It's like using it as an end table. I think it is just too close to the listening position.


I will try the above, if it doesn't help, I will try the move when I get some time.


Bill you lost me with the 1/4 wavelength, but I understood "It's not" Thanks
 

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If your sub has a crossover set it to the highest possible setting or defeat it completely if it lets you. Then set the receivers low pass for the sub at 80 and high pass for the speakers at 80 and see how you like it


Sent from my HTC6500LVW using Tapatalk
 

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Quote:
Originally Posted by dmb12679  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24509877


I have very limited space up front and currently have it in the backside of the room by where my wife and I sit. The bass is just annoying, you can tell by ear exactly where it's coming from and at times you can hear low vocals which just sounds terrible.

As others have pointed out, we see all of the symptoms of a badly integrated subwoofer in your statement of your problems.


Again, as others have pointed out there is either no effective low pass filter on the subwoofer or it is set way to high. 80 Hz is a good starting point but you may need to go lower.
Quote:
Up front, I have an end table that would fit my sub under it, but the Sub would have to sit on the bottom wooden level about 4" off the ground. I would be able to anchor it to the table, and eliminate movement and vibration noises.

The effects of speaker positioning are relative to the wavelength of the sound waves that are involved. If you cross the sub over at 80 Hz we are talking wavelengths on the order of 14 feet. 4 inches is a tiny fraction of that. Ordinarily raising or lowering a subwoofer by that amount does not have a very strong audible effect.
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Is it a must to have it on the floor, how much sound/vibration will I loose?

Ordinarily little or none.
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Maybe I'll just give it a try when I get a chance, any suggestions if its worth it.

A half hour of experimentation with speaker placement can trump hours of discussion. However, lets not forget the crossover sitaution. Your Harman 3700 has credible bass management but it is easy enough to misadjust it. A good early move would be to turn the crossover frequency to lower frequencies until its location is not so apparent. Your RB51 are not the best speakers in the world for use with crossover frequencies below 50 Hz, but if your preferred listening levels are not too high, you may have some flexibility available to you.
 

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I agree try adjusting your crossovers..... In my old house I used to use one of my two subs as an end table. No one new it was a sub unless I told them. The bass just eminated throughout the room you couldn't tell at all that the sub was right next to you. I used 80hz crossovers all the way around and disabled the subs crossover ( had it set to highest freq to let receiver handle bass management).
 

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Quote:
Originally Posted by dannybenz  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24510511


If your sub has a crossover set it to the highest possible setting or defeat it completely if it lets you. Then set the receivers low pass for the sub at 80 and high pass for the speakers at 80 and see how you like it
One of the main reasons for sub localization is that AVR crossover filters are not brickwall, so they may pass sufficient above bandwidth content to be easily heard. Cascading the low pass filter of the sub along with the AVR crossover can reduce, if not eliminate, that above bandwidth content. There is no valid engineering reason not to do so.
 

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Quote:
Originally Posted by dmb12679  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24509877


I have very limited space up front and currently have it in the backside of the room by where my wife and I sit. The bass is just annoying, you can tell by ear exactly where it's coming from and at times you can hear low vocals which just sounds terrible.


Up front, I have an end table that would fit my sub under it, but the Sub would have to sit on the bottom wooden level about 4" off the ground. I would be able to anchor it to the table, and eliminate movement and vibration noises.


Is it a must to have it on the floor, how much sound/vibration will I loose?


Maybe I'll just give it a try when I get a chance, any suggestions if its worth it.
As others have mentioned, your crossover is causing these problems. What speakers do you have? Does your receiver have some kind of auto-setup routine, such as Audyssey, YPAO, or MCACC? If so, did you use it? If not, what caused you to set the crossover higher than 80 Hz?


Lowering the crossover *may* solve the problems you currently list, but it may also cause other problems.


Craig
 

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Quote:
Originally Posted by Bill Fitzmaurice  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24511058

Quote:
Originally Posted by dannybenz  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24510511


If your sub has a crossover set it to the highest possible setting or defeat it completely if it lets you. Then set the receivers low pass for the sub at 80 and high pass for the speakers at 80 and see how you like it
One of the main reasons for sub localization is that AVR crossover filters are not brickwall, so they may pass sufficient above bandwidth content to be easily heard. Cascading the low pass filter of the sub along with the AVR crossover can reduce, if not eliminate, that above bandwidth content. There is no valid engineering reason not to do so.

I did not imply that that crossover are a "brickwall". Usually the slope can be set in the AVR. There a a couple of reasons why I would avoid using the sub's low pass filter. In one word, here's a potential reason a steeper filter can negatively effect integration: phase.


Sent from my HTC6500LVW using Tapatalk
 

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Quote:
Originally Posted by dannybenz  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24518115


I did not imply that that crossover are a "brickwall". Usually the slope can be set in the AVR.
If there are AVRs with the ability to alter the slope of the low pass I'm not aware of them. If they exist it's not within the price range that most users can afford.
Quote:
There are a couple of reasons why I would avoid using the sub's low pass filter. In one word.. phase.
Higher order slope filters reduce the influence of phase, as there's less overlap in the pass bands of the subs and mains. In pro-sound we routinely use 4th, 6th and even 8th order filters, with no ill effect. If anything higher order filters give better results. Phase in and of itself is inaudible. It's only when the phase of two or more sources playing in the same pass band approach 180 degrees that it's audible. The smaller the region where said sources have overlapping response the smaller the bandwidth where phase can have a potential effect, and that's realized with as high a slope as possible.
 
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Quote:
Originally Posted by Bill Fitzmaurice  /t/1523548/how-important-is-it-that-the-subwoofer-is-on-the-floor#post_24511058



One of the main reasons for sub localization is that AVR crossover filters are not brickwall, so they may pass sufficient above bandwidth content to be easily heard. Cascading the low pass filter of the sub along with the AVR crossover can reduce, if not eliminate, that above bandwidth content. There is no valid engineering reason not to do so.
This worked well for me when setting up my subs.  By using one of my subs crossover in conjunction with an 80 Hz crossover in my AVR, I was able to eliminate a 60 Hz peak in my frequency response without using eq.
 
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