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Optimizing Speaker Placement and Listening Position using REW

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tallbeardedone

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Hello,
I have been following your thread and I like what you are doing. A future project of mine is to do something similar, once I get set up to use REW, etc.
I have my speakers set up a lot different than you do. And I have never ever done anything in/with/etc. REW. In fact I still play discs, but I have the capability to run REW once I get a microphone. It would be a great way to see what I have.

Here is how I have my speakers set:
https://www.audioaficionado.org/showthread.php?t=46634 . I follow the instructions in Post #2, to the letter.
This is a process, called a few different things which do not matter. It is a great way to place speakers in a room and lets one free to sit in a much larger area than the single spot still as a statue way that I read you are doing.
I should add that I first heard speakers set this way back in 2007 at an exhibit room at RMAF. Over time I learned how to do this and became successful in doing it. The above instructions allowed me to fine tune and tweak what I already had. The instructions themselves are the way to go about this, and they give very precise descriptions was what to do and what to listen for. I recommend the Ballad of Runaway Horse song for doing this as it works very very well, and better than anything else.

You may want to try this and see how it goes. I would think the use of REW in the process could be quite useful, and you are well versed in this.
And if you don't like the results you can always just move your speaker back to their current position, as you have them well marked and documented in the room.

Keep up the experimenting and posting of results.

Steve
That’s exactly how I set up my speakers originally! Lol. If you’re interested in the Master Set technique I’ve compiled a doc that has five different sets of instructions, all with slightly different details in different areas (toe-in at the start vs after anchor has been set, etc).

I emailed Bob Robbins of https://www.myspeakersetup.com/ extensively while first setting up my speakers. I can give you all his advice as well but I’d suggest paying for Bob’s personal advice if this is the route you want to go. He’s super helpful and replies quickly. I’ve shown him all my REW results as well and he thought it was super interesting but he’s definitely a listen with your heart as a guide guy.

Having said that my current process of starting with Master Set then using REW sweeps has netted much better results than I was able to do only by ear and “listening with my heart” as Bob advises.

For example, my speakers bass response sounded quite good with my speaker closer to the wall but I would never have known of the massive 140hz suck out at that spot if I hadn’t measured with REW.

If I’m honest I don’t think it’s possible due to the physics of sound reproduction to have more than one perfect listening spot for the fully immersive 3-D soundstage I’ve described. Sure, the speakers sound great and “disappear” anywhere along the mid-line, but there’s only one exact spot where you can step “through the wall” and into the room of the recording. It’s the physical place in space relative to where the microphone was during the recording. Put your head there and BOOM, mind is blown.

Just my two cents from what I’ve found in my listening room through very exacting placement tinkering! Enjoy the tinker!
 
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tmuikku

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A Finn! Very cool. I'm in New Zealand but grew up in Minnesota where there is a large Scandinavian population. I actually have "sisu" tattooed on my hand and a Finnish sauna in my back yard! Also my novels star a hulking Finn named Einarr "Sledge" Laukkanen. :cool:
Nice :D
Sound sooo fun. I'd love to come tinker. My only speaker building experience is with paper, wire and neodymium magnets in my physics class. :p
Unfortunately its about half-a-globe journey :S Well, at least internet makes physical distance go away so a nice chat on forums is possible without much trouble :)

I've been pondering getting a miniDSP or the like to add EQ to my signal. Not sure I want it but I could attenuate that 65hz anti-node and flatten response even more across the entire band. The thing about EQ is it's flattening the sound at the listening position which is the addition of direct and reflected sound (it can't differentiate the two) so maybe it's taking away too much of the direct sound or not enough? I would have to invest the money to try it out and atm I love my sound so much it seems foolish to gamble $1000+ on something that I might not even end up using. I know it's "old school" but I like the idea of having to use old fashioned speaker placement and room treatments to find the best sound in my room, not digital EQ. And that's not even considering my all-analog chain!

Some of the sound is minimum phase, meaning that you could EQ without side-effects. Most likely some of the bass peaks are and you can just dip them out with EQ. What you could also do is to "fix" or smoothen the speaker anechoic response to what ever house curve to a particular direction, or fix some issues if any.

If you fancy try EQ you could use some EQ app in phone or with computer and audition if it makes any difference. There is plenty of info around how to do this kind of stuff, REW is part of the process and its help file probably contains tips how to proceed with it. What EQ cannot do is affect the acoustics of the room or the speaker itself so its not a magic bullet. No substitute for positioning and room acoustic treatment although could help partly. And as always, don't fix it if its not broken :)
 
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tallbeardedone

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Nice :D

Unfortunately its about half-a-globe journey :S Well, at least internet makes physical distance go away so a nice chat on forums is possible without much trouble :)



Some of the sound is minimum phase, meaning that you could EQ without side-effects. Most likely some of the bass peaks are and you can just dip them out with EQ. What you could also do is to "fix" or smoothen the speaker anechoic response to what ever house curve to a particular direction, or fix some issues if any.

If you fancy try EQ you could use some EQ app in phone or with computer and audition if it makes any difference. There is plenty of info around how to do this kind of stuff, REW is part of the process and its help file probably contains tips how to proceed with it. What EQ cannot do is affect the acoustics of the room or the speaker itself so its not a magic bullet. No substitute for positioning and room acoustic treatment although could help partly. And as always, don't fix it if its not broken :)
Hey I've been doing some "soundstaging" with various recordings of Saint-Saëns' "Danse Macabre", placing all the instrument in 3-D space and drawing a visual map. This is the kind of nerdy close listening I enjoy. Anyway, I measure the noise floor of my room (~30dB +/-2dB using spl meter) and what I'm sensing is that to get the ambience and "inside the room" experience the volume of the noise floor of the recording must exceed the noise floor of my own room. That is, when I turn up the recording until the "hush" and "air" of the recording is louder than my room's noise floor, the immersive experience begins. This of course is at my listening sweet spot quite near-field.
Just thought that was interesting and wanted to share.

Also, "Danse Macabre" is the perrrrrfect recording for Halloween! The "diabolus in musica" dissonant trinote (the Devil's fiddle played on solo violin) wakes the dead and the dancing skeleton bones are played on xylophone. So damn cool.
 

tmuikku

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^ that is very interesting observation. If generalizing, perhaps too much, for better sound we could increase noise floor of the recording and reduce ambient noise in the room. Also system SPL capability plays a role.
 
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tallbeardedone

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^ that is very interesting observation. If generalizing, perhaps too much, for better sound we could increase noise floor of the recording and reduce ambient noise in the room. Also system SPL capability plays a role.
Easy to check with older recordings that have much higher noise floor “hush”.
 

tmuikku

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Have you experimented with adding noise? :D like adding tape hiss or something. Vinyl crackle and pop to modern digital recordings and sources.

I guess noise of the playback chain would contribute to room noise floor instead? This is interesting topic need to find studies about noise and perception.
 
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tmuikku

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Its very interesting indeed, if assuming system noise or ambient noise is bad for imaging (or soundstage, stereo sound quality in general), but if source noise (noise within the recorded audio, related to the audio) is not. In general, what is required for good 3D stereo sound is that source noise level overcomes the ambient noise level. then:
- What is the difference? is it just noise that differs or is there additional detail within the source noise? Is it just that the noise somehow relates to the audio?
- does this have something to do when people say some electronic devices like DACs or amplifiers affect soundstage? perhaps noisefloor of a device is better than the other and there is then better soundstage perceived? Perhaps, Instead of being static noise its modulated by the audio somehow?
- is this something why people say LPs sound better than digital sources, when technical numbers say exact opposite? perhaps higher noisefloor of analog medium has got something to do with it? But this is system noise isn't it and should be detrimental instead?

So is vinyl/tape noise affected by the signal embedded then? meaning that the sound modulates the noise at playback? in which case the noise is not static, uncorrelated system/ambient noise, but connected to the sound and give answers to some of the questions above?

If there is truth in logic of text above that ratio of non-audio related noise to audio related noise affects perceived stereo sound quality then following reasoning could take place: digital sources would sound superior to analog when system/ambient noise is low, because audio related noise is low. Otherwise the opposite could be true, high source noise would allow higher ambient noise for similar perceived quality. Best stereo sound quality is achieved anyway by reducing ambient/system noise no matter what the source is. Absolute value of noise doesn't mean much, could be high if noise relates to audio. Also, depending on the system/ambient noise level SPL capability of the system needs to be high in order to be able to overcome the ambient/system noise with the source noise (by increasing playback level enough). By raising system SPL level also distortion products get higher in level raising system noise and preventing source noise overcoming the system noise on some cases.

So, speculating from the above assumptions and logic: system with high SPL capability and low noise would be best in any circumstances. Also any ambient noise in the room raise bar what is required from the playback system (SPL capability) so keeping it low is paramount. Vinyl gives best sound when the playback system is poor/ambient noise in room is high, c-cassette would be even better :D

Well, anyway, not sure how much there is truth in the above. Fun thought experiment though :)
 
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tallbeardedone

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Have you experimented with adding noise? :D like adding tape hiss or something. Vinyl crackle and pop to modern digital recordings and sources.

I guess noise of the playback chain would contribute to room noise floor instead? This is interesting topic need to find studies about noise and perception.
This idea is reminiscent of random dither which is random noise that, when added, makes the dynamic range SEEM to increase. I find the physics behind that super cool.

Try this!


Also, the dynamic range of certain overly compressed digital albums measure a larger dynamic range on vinyl EVEN THOUGH THEY ARE FROM THE SAME MASTER! This agrees with the idea that somehow noise floor actually adds to a sense of dynamic range. It even measures better! Crazy physics.
 
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Cote Dazur

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Speaker placement within the room, acoustic treatment of the room, dimensions of the room, and listening position relative to speakers and walls all need to be taken into account
Yes and yes, very nice to see a set up close to what I ended up with after all those years, the room and how speakers and seat are located will yield fantastic results, punching way above their weight, if given a chance.
 

tmuikku

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Hi @tallbeardedone, I hope you are fine! I was asked by private message if I have you speaker placement docs since the person didn't hear back from you. I had it and could share it so I did, I hope it's fine.

Anyway, here few responses as you were interested about them about a year ago but hadn't any. I've got the DIY speakers tweaked some, more prototypes eliminating resonances and issues, still some to go including testing different waveguides and drivers. What goes to the 2D/3D effect it's still there, have had few friends over and they hear it too but not sure if they noticed it by themselves, I've been talking about the effect a lot so :D

Well, anyway, here goes.
Ungated sweeps at listening spot, could be MMM cannot remember, note was that its sweetspot responses, left and right respectively. Psychoacoustic smoothing applied:
LR-sweeps-around-listening-position.png
Here full speaker at it's position measured roughly 70cm away, the low mid stuff above is effects of room. Here undulations are effects of close distance that's not yet far field of the speaker as its almost meter tall system. Also psychoacoustic smoothing
roughly-at-70cm-away.png

Here sixpack from VituixCAD
six-pack.png

I'm not too happy with the graphs on low mids, but really the sound is quite fine, better than ever and after all it's speaker designed for on-wall use so not sure how good it's possible to have it. Recently been learning and thinking about listening, how to listen various aspects of sound so that it's possible to reason about the perceived things in order to develop the system further. So, lots of having fun for me, doing fine!:)

ps. have you checked out David Griesinger studies? See this for example http://www.davidgriesinger.com/Acoustics_Today/AES_preprint_2012_2.pdf
As far as I've reasoned Griesinger work seems to correlate on the 2D/3D transition, at the transition brain locks in to harmonics in the recording (phantom center) and pays involuntary attention, separating "direct" sound and "ambience" to their own neural streams making clarity on the phangom image and envelopment to happen. What do you think, is this it?
 
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