The woofer crawl is stupid

[tee]

Apologies for the click-baity title but... I do not understand the logic behind the "subwoofer" crawl. Maybe I do not understand the physics properly: I understand that the lower a frequency is, the more "omnidirectional" it is... However, any given cone needs, by definition, to face one direction. With this being true, doesn't the direction which you place the woofer in effect the... effect? For example, in the room that I currently use for my home theater (I will be moving it) the room is open into a hall way and front room on one side; the opposite side is a wall and windows (where the tv is). If I place a subwoofer on the couch, it will be facing the tv wall; if I place the subwoofer on the tv wall, it will be facing the open area. So how could this not give a different effect?

In any event, I just tried near field placement, for the first time, a couple hours ago. This is incredible, I have no idea why I hadn't tried it soon. I have my svs pb-1000 placed, on a small end table, directly behind my loveseat (MLP). I have never had such great bass, and the tactile effect is WAY better than anything I've got from transducers. If I could spare the sb1000 from my music setup I would add that also (maybe I would put the sealed behind the MLP, and the ported somewhere else in the room, in case other people are here... not likely).

Thoughts? Sorry for the long post.

 

[fpitas]

As the frequency goes down, it becomes more or less omnidirectional below the baffle step frequency. As an example, several well-regarded speakers have the woofer on the side.

 

[somebodyelse]

Since you now have the subwoofer behind tour MLP you can have an assistant point the subwoofer in different directions and find out if you can hear any difference without being able to see what (if anything) changed.

 

[Rednaxela]

Maybe I do not understand the physics properly: I understand that the lower a frequency is, the more "omnidirectional" it is... However, any given cone needs, by definition, to face one direction. With this being true, doesn't the direction which you place the woofer in effect the... effect?

As I understand it, omnidirectional in this context should be seen as literally in all directions. As if your sub had six drivers i.e. one on each face of the cube if this makes sense.

 

[fpitas]

The sound radiates away from the cone as if it were a point source. The wavelength is so long, even the cabinet doesn't matter much.

 

[DVDdoug]

n any event, I just tried near field placement, for the first time, a couple hours ago. This is incredible, I have no idea why I hadn't tried it soon. I have my svs pb-1000 placed, on a small end table, directly behind my loveseat (MLP). I have never had such great bass,

Non-directional means it's hard to locate the source of the sound

But the placement does affect standing waves, and where you are in the room affects the intensity (loudness) of the standing wave... i.e. If you are at a node, anti-node, or somewhere else in the wave, at a particular frequency/wavelength

 

[Holmz]

Since you now have the subwoofer behind tour MLP you can have an assistant point the subwoofer in different directions and find out if you can hear any difference without being able to see what (if anything) changed.

Depending on the walls, furniture, etc., it would not be unheard of to have it couple (or impedance match) better with the cone facing the wall.

 

[jsilvela]

I learned here at ASR that this is Rayleigh's reciprocity theorem.

Why the fuss with subwoofer specs and brands?

What has that got to do with the price of cheese? The only point I am trying to make is that I do not see any reason to ascribe any special requirements to movies with regard subwoofer capability compared to music in a domestic setting. I wish you knew the difference. Anyway, Happy New Year.

audiosciencereview.com

BTW I tried the subwoofer crawl, and for me it did not work because I did not know how to know when I was done.
This was more me being stupid than the crawl though.

 

[dasdoing]

it's not very time consuming meassuring all possible subwoofer positions. there aren't that many practical ones, aren't there? so yes, it is stupid

 

[AdamG]

it's not very time consuming meassuring all possible subwoofer positions. there aren't that many practical ones, aren't there? so yes, it is stupid

Well it has utility in regards to determining the best spot out of a few possible locations that would be acceptable. Say you have 3 potential locations for the sub. By placing the sub at each location and using a spl meter measuring the highest spl will help you determine the best of the three. Of course this is with the sub operating at your main listing position. Then go to each possible location and measure. The spot with the highest spl will be the optimal location. Crawling around the entire room is kind of pointless if you can’t live with the sub in those locations. JMHO

 

[ROOSKIE]

Apologies for the click-baity title but... I do not understand the logic behind the "subwoofer" crawl. Maybe I do not understand the physics properly: I understand that the lower a frequency is, the more "omnidirectional" it is... However, any given cone needs, by definition, to face one direction. With this being true, doesn't the direction which you place the woofer in effect the... effect? For example, in the room that I currently use for my home theater (I will be moving it) the room is open into a hall way and front room on one side; the opposite side is a wall and windows (where the tv is). If I place a subwoofer on the couch, it will be facing the tv wall; if I place the subwoofer on the tv wall, it will be facing the open area. So how could this not give a different effect?

In any event, I just tried near field placement, for the first time, a couple hours ago. This is incredible, I have no idea why I hadn't tried it soon. I have my svs pb-1000 placed, on a small end table, directly behind my loveseat (MLP). I have never had such great bass, and the tactile effect is WAY better than anything I've got from transducers. If I could spare the sb1000 from my music setup I would add that also (maybe I would put the sealed behind the MLP, and the ported somewhere else in the room, in case other people are here... not likely).

Thoughts? Sorry for the long post.

It was mentioned but there are room modes that affect in different ways based on both sub location and listening position.
You also have SBIR(speaker boundary interference response) that are cancellations based on boundary to driver distances and these can also be very strong and are based entirely on location.
These can incredibly strong if several boundary to transducer distances are equal.
The omni directionality and near omni directionality of certain frequencies actually makes SBIR effect stronger as the waves involve more boundaries and we as listeners 'expect' strong room gain in the bass. (The downward in room trend is really a upward trend from about 200-500hrz to 20hrz.)

 

[somebodyelse]

Building on @AdamG247's answer, the idea is to use reciprocity to save effort - it's easier to move the mic / meter / your head than it is to move most subs, so move the sub to the MLP and test at each of the possible locations before moving the sub to the best one.

 

[sigbergaudio]

For example, in the room that I currently use for my home theater (I will be moving it) the room is open into a hall way and front room on one side; the opposite side is a wall and windows (where the tv is). If I place a subwoofer on the couch, it will be facing the tv wall; if I place the subwoofer on the tv wall, it will be facing the open area. So how could this not give a different effect?

A) What prevents you from placing the subwoofer with the same orientation on the couch as when it is at the TV wall?

B) The orientation will not matter much at all.

 

[czt]

My ESI aktiv 10s sub (with REW integration) really never worked in other positions (eg. side facing at front wall thirds by Neumann) despite the better frequency responses, than placing it the same distance and direction as the full range monitors. And wall(s) proximity boosts modal peaks too much (EQ becoming mandatory). And use them as they are intended: in half-space/ground-plane.

 

[TheZebraKilledDarwin]

Apologies for the click-baity title but... I do not understand the logic behind the "subwoofer" crawl. Maybe I do not understand the physics properly: I understand that the lower a frequency is, the more "omnidirectional" it is... However, any given cone needs, by definition, to face one direction. With this being true, doesn't the direction which you place the woofer in effect the... effect? For example, in the room that I currently use for my home theater (I will be moving it) the room is open into a hall way and front room on one side; the opposite side is a wall and windows (where the tv is). If I place a subwoofer on the couch, it will be facing the tv wall; if I place the subwoofer on the tv wall, it will be facing the open area. So how could this not give a different effect?

In any event, I just tried near field placement, for the first time, a couple hours ago. This is incredible, I have no idea why I hadn't tried it soon. I have my svs pb-1000 placed, on a small end table, directly behind my loveseat (MLP). I have never had such great bass, and the tactile effect is WAY better than anything I've got from transducers. If I could spare the sb1000 from my music setup I would add that also (maybe I would put the sealed behind the MLP, and the ported somewhere else in the room, in case other people are here... not likely).

Thoughts? Sorry for the long post.

No, no, no, buy more subs and place them somewhere far away...
Have you ever been to a club? Where does the bass sound best? At the bar or on the dancefloor close to the speakers?
Congrats, that you just had to discover the truth by accident, because audio forums mostly spread only PR garbage...
But hey, Toole tells you, direct sound not good, echo chamber good...

 

[AdamG]

Building on @AdamG247's answer, the idea is to use reciprocity to save effort - it's easier to move the mic / meter / your head than it is to move most subs, so move the sub to the MLP and test at each of the possible locations before moving the sub to the best one.

Yeah, that ^^^.

 

[IPunchCholla]

I thought about doing the crawl, but I couldn’t figure out an easy way to lift the subwoofer to ear height at the MLP.

 

[ROOSKIE]

I thought about doing the crawl, but I couldn’t figure out an easy way to lift the subwoofer to ear height at the MLP.

I don't know what sub you have but you could set in on your chair.

Most likley just putting it in the spot directly below your head on the floor is fine.

The main issues are avoiding nulls due to width and length of the room and SBIR. There will be height issues though so yah I guess have a pal hold up for you

The sub crawl is old school and is pre-DSP/REW/UMIK/Dayton mic ect. In other words all the cheap measuring gear coupled with PEQ might be a better idea now. In any case the sub crawl is probabily still usefull for many. I don't do it though. Far better to measure and decide that way.

Plus what is good for some frequencies will be less so for others.

 

[Holmz]

Well it has utility in regards to determining the best spot out of a few possible locations that would be acceptable. Say you have 3 potential locations for the sub. By placing the sub at each location and using a spl meter measuring the highest spl will help you determine the best of the three. Of course this is with the sub operating at your main listing position. Then go to each possible location and measure. The spot with the highest spl will be the optimal location. Crawling around the entire room is kind of pointless if you can’t live with the sub in those locations. JMHO

Some would argue that the smoothest response trumps the highest SPL.

Building on @AdamG247's answer, the idea is to use reciprocity to save effort - it's easier to move the mic / meter / your head than it is to move most subs, so move the sub to the MLP and test at each of the possible locations before moving the sub to the best one.

… it is like the saying, “Is the mountain won't come to Muhammad, Muhammad must go to the mountain“.

 

[AdamG]

Some would argue that the smoothest response trumps the highest SPL.

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.