It's not just the relation of the speaker to the ear, it's the speaker's coupling to the room.
My Personal Experience With Detailed Speaker Setup - I'm Finally There
- Thread starter divertiti
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It's not just the relation of the speaker to the ear, it's the speaker's coupling to the room.
I’m not sure what it means for a speaker to couple to a room. My understanding of speaker room interaction is that a room has three frequency zones. The bass zone, the Schroeder cross over zone and the the midrange and high frequency zone.
In the bass zone the sound pressurizes the room and you get specific room modes which are frequencies at which you get standing waves.
The midrange and high frequency zone are the frequencies at which sound waves behave as vectors and have clear directionality and clear vectors for reflections.
The Schroeder cross over zone are the frequencies where you get a mix of the other two zones. The room modes are a function of the room. Their placement and frequencies exist independent of the characteristics of the speakers.
Much can be done to mitigate the ill effects through speaker and listener positioning. But due to the wavelength sizes a 1/16th of an inch one way or the other doesn’t have a big effect on the interaction between the speakers and the room modes. It has even less effect on the pressurization of the room in the bass region.
The interaction between the room and the speakers in the midrange and upper frequency region is a function of speaker radiation patterns, reflectivity of the room boundaries and speaker/listener positioning. The math is much simpler here and affects much more predictable. The degree to which a speaker and listening position are sensitive to small changes is largely a function of the radiation patterns of the speaker.
Being that the waves behave as vectors the sensitivity to small adjustments, whatever they may be for a specific speaker, exists at both ends of the vectors.
Im no expert on room acoustics. But I have done a lot of research on the subject. It’s a complicated and multifaceted subject. Can you maybe go into more details about coupling speakers to the room?
I think we might need to better define our movements. For example moving left/right and forward and back should have minimal effect. That said if we are talking rotational around the speakers axis its a change in toe in. I can see an angular change having a greater effect as you are shifting the polar pattern through out the room.
Rob
My starting point is that I agree tiny differences in speaker movement can make an appreciable difference at the listening position. I also agree this isn't terribly logical.
What I find personally helpful is to think that the speakers aren't the sound source. The speakers and the room together behaves as a sound source. That sound source needs to be very precisely aligned - put another way, finely tuned - to perform at its best. Lets face it, many people can hear the effect of, say, tightening the screws on the drivers in a baffle. Why is this so implausible?
Can I think of it as the speakers are the Formula 1 engine and the room is the chassis and suspension: The room and speakers together become the car?
What I find personally helpful is to think that the speakers aren't the sound source. The speakers and the room together behaves as a sound source. That sound source needs to be very precisely aligned - put another way, finely tuned - to perform at its best. Lets face it, many people can hear the effect of, say, tightening the screws on the drivers in a baffle. Why is this so implausible?
Can I think of it as the speakers are the Formula 1 engine and the room is the chassis and suspension: The room and speakers together become the car?
First let me say that I am never comfortable with denying what a listener hears, so if a 16th of an inch speaker movement has an audible effect, then I’m personally perfectly happy to accept that it indeed has a audible effect.
But I would apply some logic here. First, it‘s reported that the sound difference can be heard when walking into the room, so there‘s no relation of the speaker movement to seating position. Second, 1/16th of an inch represents 1/214,375th of a second in terms of the speed of sound. Third, even minor head movements would have similar effects to moving the speakers 1/16th of an inch, so theoretically the timing of instruments would be constantly changing even if the listener was trying to sit perfectly still. Personally I can never sit still while listening to music.
So let’s look at the facts. With a tiny movement the sound is changing and the changes can be heard everywhere, but such tiny movements are very unlikely to affect speaker performance from a spatial standpoint. So what constitutes a good alternative explanation? My guest is that nudging the speaker….literally bumping it with the hand is causing the speaker footers to move slightly across the floor. As soon as the speaker reaches a point where all 4 feet are in more perfect contact with the ground (equal pressure on all 4 feet) vibration will be reduced and the overall performance of the speaker will improve. I can perform a similar trick with a piece of paper under one foot of a TT, CDP, Amp or even a PS.
Shimming any of the above to ensure all 4 feet are in perfect contact with the support platform can have a profound affect on the music.
So I would believe that rather than it being the repositioning of the speaker spatially that’s making the difference, it is perhaps the fact that minute differences in the floor are providing better/worse contact between the 4 supports of the speaker. All it would require would be a few thousands of a millimeter to hear a substantial difference that would address all the observations.
Just to mention, I used to use a stethoscope to check the contact between spikes and spike cups of my Magico speakers. Spikes that would ‘feel‘ as though they were in perfect contact often weren’t. Using spanners to tighten spike locking nuts nearly always introduced minor maladjustments.
So just a thought regarding what may be going on.
But I would apply some logic here. First, it‘s reported that the sound difference can be heard when walking into the room, so there‘s no relation of the speaker movement to seating position. Second, 1/16th of an inch represents 1/214,375th of a second in terms of the speed of sound. Third, even minor head movements would have similar effects to moving the speakers 1/16th of an inch, so theoretically the timing of instruments would be constantly changing even if the listener was trying to sit perfectly still. Personally I can never sit still while listening to music.
So let’s look at the facts. With a tiny movement the sound is changing and the changes can be heard everywhere, but such tiny movements are very unlikely to affect speaker performance from a spatial standpoint. So what constitutes a good alternative explanation? My guest is that nudging the speaker….literally bumping it with the hand is causing the speaker footers to move slightly across the floor. As soon as the speaker reaches a point where all 4 feet are in more perfect contact with the ground (equal pressure on all 4 feet) vibration will be reduced and the overall performance of the speaker will improve. I can perform a similar trick with a piece of paper under one foot of a TT, CDP, Amp or even a PS.
Shimming any of the above to ensure all 4 feet are in perfect contact with the support platform can have a profound affect on the music.
So I would believe that rather than it being the repositioning of the speaker spatially that’s making the difference, it is perhaps the fact that minute differences in the floor are providing better/worse contact between the 4 supports of the speaker. All it would require would be a few thousands of a millimeter to hear a substantial difference that would address all the observations.
Just to mention, I used to use a stethoscope to check the contact between spikes and spike cups of my Magico speakers. Spikes that would ‘feel‘ as though they were in perfect contact often weren’t. Using spanners to tighten spike locking nuts nearly always introduced minor maladjustments.
So just a thought regarding what may be going on.
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I had an experience like that as well. Just finished building a pair of cabinets loaded in the drivers and did a slow sine frequency sweep.
Well horrors! I had a buzz and it took me a while to track it down
I had forgotten to tighten one of the nuts on the speaker terminals. I was loose and would buzz during the sweep
Tightened it up buzz gone
Careful set-up is a must
Rob
For those people who can hear such precise speaker positioning, I have a question. Do you recalibrate your speaker position as season changes. The humidity or more temperature will have effect on the movement of the flooring especially wooden floor. Carpet floor maybe affected less but wooden floor certainly will move as temperature changes. As a result, the speaker position may change. My speakers are on the wooden floor. My room is not temperature controlled room. I have observed the temperature of my room is around 19-26C during the year. So far, I did not feel the need to recalibrate the speaker position. But I easily admit that my speaker may not be in the most optimum position.
I cannot speak for others, but I personally readjust every time something is slightly "off". Whenever this happens, when I go to check? Yup. The speakers have moved ever so slightly. I will recalibrate them and after that, everything snaps back to where it was.
Tom
Tom
...I would say 99% of the time, it's me that is off. In my experience, my wet-ware, while very sensitive, is also the most prone to deviations. Mood. Work. Weather. Sweetie. Dog. Sometimes good Scotch can taste "off." What the heck is up with that? I don't trust this brain at all.
For the most part, my gear is "my rock!"
For the most part, my gear is "my rock!"
Our brains are our most sensitive, powerful (and sometimes erratic) audio component. Everything else is window dressing, imho.
Wood flooring is a problem. It it will exand and contract with seasonal humidity fluctuation. Different types of wood will be better or worse. e.g. Maple vs. Oak. Also, if the floor is on pier and beam then that will be far worse.
IMO, the best floor would be a hard bamboo on a concrete slab. See for example Roy Gregory's room info. The bamboo is hard, flat and dimensionally stable. Not to mention its vibration absorption properties.
IMO, carpet is not a problem for movement as long as the speakers are spiked to the concrete slab below. Carpet is a problem during the initial setup.
...I would add, modern engineered floors are very stable...but do still move a wee bit seasonally. In my audio room, below grade, they don't appear to move at all, but on the first floor, I can see very small migration seasonally. It is easier to keep the room below grade at stable T and RH.
What are the materials of modern engineered floors? In my long experience of wooden flooring (hardwood or lamented), one always have to allow space for them to expand and contract when laying them on the floor.
...even engineered floors are made of wood. However, the substrate (beneath the desired species one sees on "top") is more akin to plywood, in that it is glued-up in layers. The alternating layers and grain orientations adds stability/reduces movement. I have had and installed many floors of both types, and for some applications, the engineered options are preferred. Once installed, they look the same.
And to your point, one still needs to allow for minimal expansion/movement and job-site acclimation, as it is a wood product. If you bang it up super-tight and it hasn't acclimated to the home, you can see issues with gaps or tightness, albeit less that normally milled wood floor boards. Here are a couple of photos from a project using a Belgian two-part wax finish.
And to your point, one still needs to allow for minimal expansion/movement and job-site acclimation, as it is a wood product. If you bang it up super-tight and it hasn't acclimated to the home, you can see issues with gaps or tightness, albeit less that normally milled wood floor boards. Here are a couple of photos from a project using a Belgian two-part wax finish.
OK. I thought I would post 3 videos that illustrate this concept. You need to listen carefully to the oboe and the plucked bass. In the first video the bass is clearly ahead of the oboe. By this I mean we can clearly hear the bass land on the note prior to the oboe. This is easiest to hear toward the end of the oboe solo as there are a few pauses (rests). The second video shows me tapping the Spacehorn (Which weighs close to 200 pounds). It took a few of these taps (Maybe 5 or so) before the bass and the oboe aligned. Then in the third video you can hear the bass and oboe playing together.
I have cut snips from the score and pasted the together so it is easier to follow. This is just the oboe and double bass parts. I put boxes around the notes where it is easiest to hear the timing.
Video 1: Bass and oboe not time aligned
Video 2: Tapping the Spacehorn
Video 3: Bass and oboe time aligned
I have cut snips from the score and pasted the together so it is easier to follow. This is just the oboe and double bass parts. I put boxes around the notes where it is easiest to hear the timing.
Video 1: Bass and oboe not time aligned
Video 2: Tapping the Spacehorn
Video 3: Bass and oboe time aligned
Not sure the Youtube links worked. Trying again.
Bad Oboe/bass timing
Tapping Spacehorn
Good Oboe/bass timing
Bad Oboe/bass timing
Tapping Spacehorn
Good Oboe/bass timing
I'm curious if any instruments were used along the way during the setup process or if its all being done by ear? Maybe something as simple as an SPL meter or maybe an SPL meter with signal sweeps being played back so you could see/confirm changes taking place?
I've witnessed in my own room where one speaker was almost 8db louder than the other speaker was after a better than average attempt was made during initial setup. At the time this was done using only tape measures, laser pointers, levels..etc. But after some time had passed I would start noticing that the sound stage and output level seemed a bit more pronounced in that Right channel compared to the Left one. Once I broke down and pulled out my calibrated SPL meter and measured it, the problem became quite clear but without the Meter I couldn't really be sure what was going on.
In any case, the fix was a very small movement of one of the speakers that was measuring almost 8db louder. I would consider this a small movement but it was more than 1/16th. Maybe an 1/8-1/4" of the whole speaker itself... to the Left.
My assumption was that the ceiling peak on that side of the room that didn't exist on the other side of the room was a contributing factor and the small movement kicked the speaker out just enough to leave that gain zone it was apparently sitting in.
I guess my point being, I don't doubt that very small movements can make a difference but its hard to imagine how someone can really tell what is going on unless, at minimum, an SPL meter is being used along the way.
I cant say for sure if an SPL meter was being used in the case of this post or not and I'm certainly not suggesting that one wasn't used. I only bring this up because it wasn't clear how these very small movements (1/16th) were being confirmed outside of someone's hearing capabilities.
I've witnessed in my own room where one speaker was almost 8db louder than the other speaker was after a better than average attempt was made during initial setup. At the time this was done using only tape measures, laser pointers, levels..etc. But after some time had passed I would start noticing that the sound stage and output level seemed a bit more pronounced in that Right channel compared to the Left one. Once I broke down and pulled out my calibrated SPL meter and measured it, the problem became quite clear but without the Meter I couldn't really be sure what was going on.
In any case, the fix was a very small movement of one of the speakers that was measuring almost 8db louder. I would consider this a small movement but it was more than 1/16th. Maybe an 1/8-1/4" of the whole speaker itself... to the Left.
My assumption was that the ceiling peak on that side of the room that didn't exist on the other side of the room was a contributing factor and the small movement kicked the speaker out just enough to leave that gain zone it was apparently sitting in.
I guess my point being, I don't doubt that very small movements can make a difference but its hard to imagine how someone can really tell what is going on unless, at minimum, an SPL meter is being used along the way.
I cant say for sure if an SPL meter was being used in the case of this post or not and I'm certainly not suggesting that one wasn't used. I only bring this up because it wasn't clear how these very small movements (1/16th) were being confirmed outside of someone's hearing capabilities.
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