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I listen at my computer, and I want to set-up a better 7.1.


But the reason I come here is, because even with just one or two speakers, the room acoustics suck.


When I play audio at 177Hz(iirc), the sound is strong on my left side even though the speaker is in front of me. If I stand up, it sounds like it's slightly to my right, but much more 'equal.' I'm sure there are others, you get the idea though.


There are various dips in volume that go away when I stand up, above my monitors.


When the subwoofer is near my desk, it's Very quiet in front of my monitors and at the furniture, again unless I stand up. That's okay though, the sub is easily moved.... The speakers are not.


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So, what do I do? What's causing it - is it because I have a large desk? I can move this and get a smaller one...


If I have to move to a new spot in the room, I can......


Sorry for the lighting. Here it is.









 

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What you're dealing with here is common. Especially with only one driver for LF content, it's very easy for patterns to develop in the interactions of the soundwaves (intereference and standing waves). For the most part, the longer waves (low frequency, below 250 or 300 Hz) diffract around the furniture in the room, so the size or shape of your desk, for instance, is largely irrelevant.


There are a few relatively manageable factors that influence the "evenness" of bass response.


First, location of your sub. Experimentation is likely the only effective technique here, but you should work first to find the location in the room that produces the smoothest response. Try a few, like the midpoint of walls, corners, 1/3 the way down a wall - don't forget to try some positions off the floor (imagine your room as a box, in three dimensions - there's nothing different about the floor compared to the wall).


Second, you can try to change the way the soundwaves reflect in your space - by that I mean, absorb some of the sound evergy at the locations where it is reflecting. This is usually accomplished through bass traps. The simplest solution is bags or bins (made from material that is as acoustically transparent as possible) filled with fluffy insulation. You can read about lots of people's experience with bas traps if you search this forum.


Third, you can add LF drivers. An additional subwoofer at a second location in your room will change the interference pattern and typically smooths the response, both in terms of the spatial and spectral (frequency) smoothness. There's lots of theory for this, but again experimantation with number of subs and location is likely the most fruitfull approach. The only rule of thumb I'd recommend is that mosre subs is almost always better (4 looks to be faily optimal in terms of bang for the buck, IMO, but two is a sgnificant improvement over one).


Lastly, (though I'm sure I'm skipping some other good ideas) you should, after you've done whichever of the other steps you're going to, apply some kind of equilization to cut power from the signal at the frequecies that are obnoxiously loud. Hopefully your soundcard or amp already has this functionality, but you may consider outboard EQ. If you shop for one, the more options for cutting (or perhaps boosting) at different low frequencies, the better.


This in not any kind of comprehensive guide, but should get you started.


Fred
 

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I would start first with pointing the speakers towards where your ears are when you sit. It looks like your fronts are too high and your center too low. The surrounds need to be to the side of your ears in somewhat similar distance. The subwoofer may be under the desk. I would stop at 5.1. Once they point towards you and sound is ok where you sit, you forget about how it sounds somewhere else in the room.
 

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Get Everest, or Toole, or any decent book on acoustics, or read up about it at www.realtraps.com . Room modes and reflections provide bumps in the frequency response, and having a wall on the left side and open on the other is probably why the left side sounds different.
 

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Quote:
Originally Posted by icor1031 /forum/post/20911501


I listen at my computer, and I want to set-up a better 7.1.


But the reason I come here is, because even with just one or two speakers, the room acoustics suck.


When I play audio at 177Hz(iirc), the sound is strong on my left side even though the speaker is in front of me. If I stand up, it sounds like it's slightly to my right, but much more 'equal.' I'm sure there are others, you get the idea though.


There are various dips in volume that go away when I stand up, above my monitors.


When the subwoofer is near my desk, it's Very quiet in front of my monitors and at the furniture, again unless I stand up. That's okay though, the sub is easily moved.... The speakers are not.


------


So, what do I do? What's causing it - is it because I have a large desk? I can move this and get a smaller one...


If I have to move to a new spot in the room, I can......

Like others have said, what you're experiencing is a combination of destructive, and constructive interference. As the names imply, constructive interference causes strong points, destructive causes nulls. Examining your listening space, what immediately jumps out at me is the significant asymmetry with regard to the left and right acoustical aspects in your immediate surroundings. So, it's not surprising you mention one of the effects associated with your left side. A quick and dirty method to address this is some type of acoustic absorber on the left wall from about where your receiver is, to the A/C unit. One 2x2, or 2x4 fiberglass panel wrapped in fabric would do wonders if you mounted it there, spaced off the wall somewhat.


Again, as others said, it's paramount to have your speakers aimed directly at the listening position. This will increase the "air", or the apparent high frequency extension of the experience. IMO, ideally you want an ITU 5.1 set-up. This places the mains at 30 degrees each side of center, and the surrounds about 10-15 degrees behind the listening position. That's a great start. Then, place your sub where it results in the strongest, yet smoothest response.



Good luck
 

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Not sure about the sound issues, but for goodness sakes put some weights on that bar. What is the heck is that, 15lbs for finger curls?


cheers,


AJ


Btw, have you considered using just 5.1 instead? And is that your sub way over to the right?
 

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Quote:
Originally Posted by ajinfla /forum/post/20919747


not sure about the sound issues, but for goodness sakes put some weights on that bar. What is the heck is that, 15lbs for finger curls?

1001... 1002... 1003...
 

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have you tried making your set up more symmetrical? like moving your display setup to the center of the desk & make it look like a cockpit like setup? that way the speakers are more symmetrical to room boundaries
 

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Quote:
Originally Posted by AJinFLA /forum/post/20919747


Not sure about the sound issues, but for goodness sakes put some weights on that bar. What is the heck is that, 15lbs for finger curls?

And I was trying to figure out is that a Canon zoom lens on the desk and why there are 2 A/C units in the room instead of 1.....hopefully those are off during listening....
 

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Quote:
Originally Posted by AJinFLA /forum/post/20919747


Not sure about the sound issues, but for goodness sakes put some weights on that bar. What is the heck is that, 15lbs for finger curls?

looks like 75lbs used for shoulder presses. You do know the bar itself is probably 45lbs, no?? One of us grew up in a family run weight lifting business. I had roid freaks around me until I was 18
He has 45 and 35lbs plates below reading for that serious bench press.....lighter, more reps is always a better choice.


You trying doing 30 of those AJ
 

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Sorry to the OP, its the forum at its finest.


Unless you re-organize and treat your room to remove cancellation sound waves you are not going to get much of a solution. You are getting strong reflections off the close wall, antime you have a boundary near your speakers that boundary effects the speaker's performance. You could buy a 2'x4' panel for that wall, mount it and find out if it did anything??
 

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:
Quote:
Originally Posted by penngray /forum/post/20922164


You are getting strong reflections off the close wall, antime you have a boundary near your speakers that boundary effects the speaker's performance. You could buy a 2'x4' panel for that wall, mount it and find out if it did anything??

Whoa,...great idea




You're right Penn,...the forum at it's finest.....
 
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