# reduce standing waves and acoustic issues



## chalado (Apr 19, 2014)

Hello Members

I'm new here in the shack and i hope someone can help me optimizing my room, i have lots of problems with standing waves and positioning.
First of all you may need some information about my equipment, it's nothing special but for me as student it's a complete new world in comparison to the usual logitech systems 
AVR: Yamaha RX-V473
Loudspeakers: Wharfedale Diamond 10.2
Music source: PC with internal soundcard(i use the analog stereo port)
Measuring software: Audionet Carma
Mic: The one that came with the AVR seems to do the job quite well

The horrible acoustics is mostly because of my room type, I have attached some pictures, they will explain..

I have also attached the waterfall diagramm of right and left speaker on my two favourite listening positions, the armchair more or less in the center of the room, and on the bed at the rear wall(i know, it's not a good position)

It would be very nice if somebody could help me and win the fight against the soundkillers addle:
Also if you need some more information, just tell me what is missing.

My Room(the position of the speakers is only temporary, there are two pics showing the original position):










































the original position:














and the waterfalls:
left armchair:







right armchair:







left rear wall:







right rear wall:


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## Wayne A. Pflughaupt (Apr 13, 2006)

Welcome to the Forum!

Unfortunately we can’t tell much from your graphs. For starters, waterfalls are only relevant below ~3-400 Hz, and their accuracy depends on measurements from an accurate (read calibrated) mic. For instance, the 10-15 dB bass boost the graphs show seems unfeasible in a room this large from speakers with 6.5” woofers. There are acoustics measurements, such as RT60 and ETC, that can be done with virtually any mic, but that’s not the case with waterfall graphs.

Which begs the question, exactly what is your complaint with the acoustics? Is there an actual and audible sound quality issue that you have observed, or are you just alarmed by a scary-looking graph (that might not even be accurate)?

You are aware that the only way to improve acoustics is to add treatments, right? Are you willing or able to do that? A good start would be to carpet the floor (unless it already is – hard to tell from the pictures) and add heavy window coverings.

Regards,
Wayne


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## chalado (Apr 19, 2014)

Well my main issue is that on my two listening positions, on the chair and on the bed, the sound below 200Hz seems to be completely not linear, there is a hole at around 115 Hz especially from the left speaker. And yes, it changes the sound, I moved the right speaker down from that construction just besides the AVR so that it's not hidden behind the edge of the wall and the sound improved a lot. The floor is carpet and the window covering can't really be changed, because my parents won't allow that.
I am not only alarmed by the graph, I was alarmed by the horrible low-frequency-acoustics on my listening positions so I decided to analyze the room, just to find out where those standing waves come from.
I would like to improve the acoustics first of all by changing the position of the speakers or maybe with some cheap and simple room modifications, I'm only a student with a small budget so I need to stay below some limits.

Please excuse me for my english, it's not my mother tongue, but I hope you understand what I want to say.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Non-linear response in the lower frequency range is normal in any room. Unfortunately low frequency treatments are expensive and invasive (as they are physically large). Your best options for improving low frequency response is to experiment with different speaker locations (although judging by your pictures it looks like you don’t have a lot of options for that), or getting a newer receiver that has auto room EQ. If funds are limited, something like a used Yamaha RX-V2500 might be an affordable option – it has a very effective 1/3-octave parametric equalization.

Regards,
Wayne


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## chalado (Apr 19, 2014)

Buying a new AVR unfortunately is not an option for me, but i'm already experimenting with the position of the speakers. What would you say about lowering them to the same height as the AVR and moving them a bit towards the center of the room?


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## Andre (Feb 15, 2010)

Try them on the window side, about six feet apart at a height with the top of the speaker is at the bottom of the window. See if there is a difference in sound with the blinds down or up. Try a different orientation of the speaker (on its side or upside-down)


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## chashint (Jan 12, 2011)

The speaker height should be set so the tweeter is at ear level when you are seated at the primary listening position (you have to pick one spot as primary) .
There should be nothing in front of the speaker, if it is sitting on a desk it needs to be pulled forward so the desktop does not extend past the front of the speaker.
Normally speakers sound better located away from walls/ceilings. 
It has been pointed out you need a calibrated mic to make measurements with, the mic will need to be located at ear level at the primary listening position.
The same is true for mic location when you run the auto calibration in the AVR (if the AVR has multiple mic locations they should all be near the original mic location, not scattered around the room).
In that room your speakers are not going to have a lot of bass. If no subwoofer is present make sure the AVR is set for front left/right speakers only, no subwoofer.
Run the auto cal and see how it sounds.
More soft furniture and bookcases loaded with stuff (especially books of various sizes) will soften the room.


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## chalado (Apr 19, 2014)

The AVR settings are all correct and the YPAO-measurement doesn't really do anything for me, it makes the sound unnatural and a bit pushed up, I don't know if I'm just a bit strange but without YPAO it sounds more natural for me. This weekend I'll try different things out and then I'll post the results if they're worth it 

Has somebody got a configuration file for Carma for the Yamaha mic that's included with the AVR (RX-V473)? that would be very nice

Andre, do you mean I should rotate my entire room setup by 90 degrees or just change the left speaker?


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## Andre (Feb 15, 2010)

in my humble opinion, best case senario is to move the speakers down so as chashint recommends, the tweeters are at ear level. Since doing that in their current location wouldn't work I suggest the location of under the window, about a foot away form the rads. The windows are reflective which will effect the sound of the speaker (however you make like it or you may not). Lowering the blinds may help with that reflection. If the speakers must stay in their current locations I would play with their orientation i.e. upsidedown (tweeter on the bottom), on on its side (tweeter inward OR outward), something may cause a eureka moment, or it could atleast make it sound maginally better. 

All the wood and glass in your room makes it very "live" i.e. reflective. You can add some panels up but it may or may not help. Some heavier curtains may help but that would remove the view which i am sure is one of the reasons you live there.


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## chalado (Apr 19, 2014)

I understand, I'll focus on lowering them and as you say try them in different orientations. Move everything under the window side is not possible for me because I'd have to change my whole room setup and it wouldn't fit very good.. you can't imagine how many hours I spent on that already.
What I thought about some weeks ago was to hang something like a blanket on the topsoil to lower the room a bit and to suppress the effect of the diagonal sopsoil, good idea or not?


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## Andre (Feb 15, 2010)

Give it a try, you never know, it would have to be a thick blanket. And since your fiddling, try putting a pillow behind the speaker, it "may" add some dampening, its a cheap experiment. If either or both of those things work you can look at better accoustic material for those locations.


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## chalado (Apr 19, 2014)

Nice idea, would be great if it works, and simple  I'll have to find a blanket now, can't wait until weekend to try it out


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## John N (Jan 2, 2007)

You could build an "acoustic cloud" and put LED or rope lights above . Would have a nice effect with Pink Floyd .


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## chalado (Apr 19, 2014)

I thought the same  Maybe something like an arduino that gets the soundsignal too and makes light xD would be a nice project for the summer holidays..


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## Babak (Mar 20, 2009)

Hi 

First of all you should get decent speaker stands.

Your speakers are on boxes that resonate very nicely, mainly in the bass. 

Second, try to listen in a smaler triangle,put the chair and the speakers closer together, about 2 to 2,5 metres. 

After that you can think about other measures. 

Cheers 
Babak


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## phazewolf (Feb 5, 2012)

I agree speaker stands would be a nice thing and tweeters have to be at ear level if at all possible. 

Something you can try and it costs nothing is just start moving the speakers and where you sit around the room and find what sound the best then go from there.


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## chalado (Apr 19, 2014)

Hello Guys, I'm sorry I didn't post anything until now, but I'm quite busy with school at the moment...
But I took care of babak's and phasewolf's advice and am now looking for some stands.
I also changed the spatial arrangement so that the right speaker gets enough space and the wall on the oposite of the windows is a bit more covered with stuff.
When I have time I'll build the stands by myself, as I read they only have to be heavy and stable enough, no specific requirements. Do I need anything to put between stands and carpet floor?

I'm looking forward to show you the results, I hope time doesn't run too fast 
And thank you for your patience, it's very nice


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