The woofer crawl is stupid

[tee]

I appreciate all the responses. I didn't get much sleep, so this may not be the best time for me to post, but I will anyways.

The main thing that I am thinking is different is the fact that it is on the couch. How can the couch not effect the way the waves propagate? To say that the couch doesn't absorb anything does not make any sense to me. It's a big, thick piece of stuff.

I'll have another look over all the answers tomorrow since I am tired at the moment.

If anyone has suggestions on books or other resources that cover more of the physics involved I would appreciate it. I should probably just take a physics course anyways heh

 

[NTK]

I appreciate all the responses. I didn't get much sleep, so this may not be the best time for me to post, but I will anyways.

The main thing that I am thinking is different is the fact that it is on the couch. How can the couch not effect the way the waves propagate? To say that the couch doesn't absorb anything does not make any sense to me. It's a big, thick piece of stuff.

I'll have another look over all the answers tomorrow since I am tired at the moment.

If anyone has suggestions on books or other resources that cover more of the physics involved I would appreciate it. I should probably just take a physics course anyways heh

Here is a screen snip of a paper in the Journal of the Acoustical Society of America (this paper is open access, link is at the end of this post):

Reciprocity is a fundamental property of elastic wave propagation. It enables us to exchange sound source and sound receiver to simplify measurements in a lot of cases, and sub crawl is one of them.

Acoustic reciprocity: An extension to spherical harmonics domain

Acoustic reciprocity is a fundamental property of acoustic wavefields that is commonly used to simplify the measurement process of many practical applicati

pubs.aip.org

 

[fpitas]

I think we can all agree a pub crawl is better.

 

[Deleted member 21219]

The main thing that I am thinking is different is the fact that it is on the couch. How can the couch not effect the way the waves propagate? To say that the couch doesn't absorb anything does not make any sense to me. It's a big, thick piece of stuff.

People can easily underestimate the difference between sound wave characteristics at 20Hz, 200Hz, 2,00Hz and 20,000Hz.

Your couch (and room furnishings) will absorb higher frequency soundwaves the way a shore line absorbs the sea's waves. Small waves are absorbed. Somewhat larger waves are both absorbed and deflected (reflected), and secondary wave travel might be obvious.

But there's no way that shore line has any effect on a tsunami. The tsunami doesn't need to be a high wave, it just needs to be a certain length. The buildup over time overcomes the shore, and the water continues on its way relatively unaffected.

A 20Hz wave in air is over 55 feet long! The couch, although absorptive, is puny compared to the length, propagation and duration of the wave.

So your couch may have an effect on 2kHz and 20kHz waves, but not on 20Hz waves.
If that couch covered your complete wall, then that might be another story.

Jim

 

[dasdoing]

Here is a screen snip of a paper in the Journal of the Acoustical Society of America (this paper is open access, link is at the end of this post):

View attachment 295650

Reciprocity is a fundamental property of elastic wave propagation. It enables us to exchange sound source and sound receiver to simplify measurements in a lot of cases, and sub crawl is one of them.

Acoustic reciprocity: An extension to spherical harmonics domain

Acoustic reciprocity is a fundamental property of acoustic wavefields that is commonly used to simplify the measurement process of many practical applicati

pubs.aip.org

I am actually starting to like this, because what I forgot in my previous post is that while in the 2d plane subwoofer placement might be limited to few locations, the inverting actually anables us to find a better height (if there is) in the 3d plane, and off the floor more possible locations might apear to be practicle. obviously not using our ears, but a mic and RTA.
talking about height, the subwoofer at listening position needs to be at ear height, too. so putting it on the couch will distort the result

 

[IPunchCholla]

People can easily underestimate the difference between sound wave characteristics at 20Hz, 200Hz, 2,00Hz and 20,000Hz.

Your couch (and room furnishings) will absorb higher frequency soundwaves the way a shore line absorbs the sea's waves. Small waves are absorbed. Somewhat larger waves are both absorbed and deflected (reflected), and secondary wave travel might be obvious.

But there's no way that shore line has any effect on a tsunami. The tsunami doesn't need to be a high wave, it just needs to be a certain length. The buildup over time overcomes the shore, and the water continues on its way relatively unaffected.

A 20Hz wave in air is over 55 feet long! The couch, although absorptive, is puny compared to the length, propagation and duration of the wave.

So your couch may have an effect on 2kHz and 20kHz waves, but not on 20Hz waves.
If that couch covered your complete wall, then that might be another story.

Jim

Unrelated, but your comment prompted me to look up how Tsunamis function, which then led me to the largest wave recorded: https://en.wikipedia.org/wiki/1958_Lituya_Bay_earthquake_and_megatsunami

 

[Holmz]

I appreciate all the responses. I didn't get much sleep, so this may not be the best time for me to post, but I will anyways.

It is not a sin to like scotch

The main thing that I am thinking is different is the fact that it is on the couch. How can the couch not effect the way the waves propagate? To say that the couch doesn't absorb anything does not make any sense to me. It's a big, thick piece of stuff.

Lol

I'll have another look over all the answers tomorrow since I am tired at the moment.

If anyone has suggestions on books or other resources that cover more of the physics involved I would appreciate it. I should probably just take a physics course anyways heh

Maybe one or two.

 

[Holmz]

I am actually starting to like this, because what I forgot in my previous post is that while in the 2d plane subwoofer placement might be limited to few locations, the inverting actually anables us to find a better height (if there is) in the 3d plane, and off the floor more possible locations might apear to be practicle. obviously not using our ears, but a mic and RTA.
talking about height, the subwoofer at listening position needs to be at ear height, too. so putting it on the couch will distort the result

3D?
you are sort of dissin the flat earthers now….
That is just not right

 

[Holmz]

Yeah, it’s called the sub craw to make it easy for most to figure out. A rough order of magnitude guide. If you want optimal results you need REW and a Calibrated Mic. Your just making me explain what we both already know because you wanted to catch me out. Or try. Grind your axe somewhere else.

Easy… I‘m not try to grind an axe, however you and I knowing it, does not help the fellow or lady that asked the question.
I was just trying to help here.

We are all generally busy and sometime the responses are not as smoothly expressed as our understanding. Usually that is me doing it.
We are usually in general alignment, just time zones differ and it get worse if I post before covvee, and in the evening there is a different excuse for me… and a crawl.

 

[AdamG]

Easy… I‘m not try to grind an axe, however you and I knowing it, does not help the fellow or lady that asked the question.
I was just trying to help here.

We are all generally busy and sometime the responses are not as smoothly expressed as our understanding. Usually that is me doing it.
We are usually in general alignment, just time zones differ and it get worse if I post before covvee, and in the evening there is a different excuse for me… and a crawl.

Fair enough. I agree with the difficulty of smooth expression of thoughts. All good Mate.

 

[Alice of Old Vincennes]

Still need the crawl. Just move chair and place sub. Don't overthink. Often, best location isn't feasible. Like the doorway or middle of the room.