What way do you prefer your subwoofers air port direction?

[Hopelion]

I have always heard that placing the subwoofers port towards or against a flat wall is the best way to face your box. What are your thoughts on this?

[Motifator]

There's actually a terminological term to that, bass reflex or ported out or something, not on top of my head. But yeah, bass to the rear is what I prefer.

Usually when the bass hits the wall, the speakers tend to have more spacing for bigger tweeters up front, etc.

[keskparane]

IME there is usually some indication of the rear of the sub. I would point this towards the wall as I believe it is the way it was designed to be used.

[Heats with Nvidia]

It doesn`t matter a lot. Almost all subwoofers used in a home setting are non-directional.

That means it sounds from all directions the same way. The position of the subwoofer in the room, on the other hand, changes its sound and how its distributed in the room, a lot.

When the subwoofer is placed at the wrong spot, you will have places in the room the the bass is extremely loud and then others where its almost dead silent.

[LogicalDrm]

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[cmndr]

This barely matters. Don't worry a ton about it. 
If you're worried, do some frequency sweeps. 

[Motifator]

6 hours ago, cmndr said:

This barely matters. Don't worry a ton about it. 
If you're worried, do some frequency sweeps. 

Nope, it actually does depending on config and dB levels.

The further you go up the higher volume and bass levels, you get to hear more bass blown on your face.

With the PA's for example, the whole thing sends bass response on your face shaking the whole room even with an 8 incher if you play a literal bass guitar. Clearly so, not every user uses garbage audio gear. Even so, this guy, since he's asking it... likely uses something where this orientation matters.

This is not a neckbeard argument but rather, something that matters.

Just like open back speaker cabinets vs closed back.
 

 

[cmndr]

One FYI, most of the sound in the video you linked to is ABOVE the frequency played by a subwoofer, it'd be played by other speakers in a home listening setting. The angling of NON subwoofers absolutely matters. 

 

The tuning frequency of a cheap subwoofer would be around 50Hz or so and more expensive ones would generally be more around 20ish Hz or so. 50Hz corresponds with a wave length of 23' which is going to dwarve the impact of a port being in one spot or another. The entirety of the subwoofer can be thought of as a sound generating resonator. The entire box is pumping out sound, though there might be some nearly negligible differences in phase, group delay, etc. I say negligible because the effect of the sound waves bouncing off the walls, floor and ceiling is going to matter something like 10,000x as much. And this effect will be different in different rooms. Also it'll be VERY minor - think 20' sound wave vs 0.5' head with ears not 20' apart (so phase differences don't matter) - not entirely relevant but there's some decent info on phase/group delays wrt sound localization here: https://en.wikipedia.org/wiki/Sound_localization

Moving the subwoofer forward/backwards, left/right or up/down can matter. Rotating the subwoofer is going to be a rounding error. The entire thing effectively acts as a single unit. It also often excites nearby surfaces (think coupling effect with walls). The main exception is if the port is effectively blocked but even that is NOT profound.

So...

subwoofer positioning absolutely matters (having 2 is nice) but rotation is WAY less important than the location in the room. The ideal location will vary by room and usually best determined by placing the subwoofer at ear level in the listening position and then doing a bunch of frequency sweets and measuring with a calibrated measurement microphone. Barring that if you have multiple subwoofers, corners are a good starting point as are spots 25% into the room. Then there's fun with phase, time delay, etc. that can be fiddled with using a DSP.

I've spent some time with this... 

 

For what it's worth SEALING port(s) can have an effect as well, it's not nothing but it's also usually not night/day. 

[Motifator]

Yeah I'm not saying NIGHT and DAY but still, more of a thing if you murder your ears at high volumes lol.

[cmndr]

On 3/26/2024 at 12:47 AM, Motifator said:

Yeah I'm not saying NIGHT and DAY but still, more of a thing if you murder your ears at high volumes lol.

It's negligible. The impact in most rooms is going to be so small it won't be perceptible to a human. Note that I'm conditioning this on a given room... subwoofer positioning and room conditions absolutely affect things.

This is measurable and the science was settled well before either of us was born. 
It's like saying that the direction of a jack hammer impacts how loud it is. Nope. 
Whether there's a couch 10 feet away is going to matter more since that'll impact sound absorption and reflection. 

If you REALLY want me to run a test I can dig up my calibration microphone and do a frequency sweet for ONE subwoofer rotated in a few ways (might take a week or so to get around to this, I'm busy). 

 

The ENTIRE subwoofer vibrates when it makes sound. It excites the entire enclosure along with surfaces immediately near it. Recall how you said even a small sub can shake an entire room... the entire room is being excited. 

 

What you're saying is absolutely correct for higher sound frequencies though. For higher frequencies the angle of a speaker matters a lot. 

Here's the radiation plot for the main speakers that I use. You'll notice that at around 300Hz and below it's deep red all over (full intensity). It doesn't matter what angle you're at relative to the speaker, you're getting around the same sound radiation intensity whether you're 0 degrees out (theta of 0) or you're 180 degrees out. 

The flip of it, at 10,000Hz, if you're more than around 20 degrees off from on axis, you'll have -3dB attenuation (50% signal strength loss) and at 100+ degrees out you'll have around 30dB attenuation (99.9% attenuation) relative to on axis. 

 

If you're curious about the small bits of attenuation around 30Hz... that's largely an artifact of port design on a set of speakers designed to do 60-20000Hz. Bookshelf speakers are not putting out much total sound in that frequency range anyway (when played at full range; with a crossover set and low frequnecies routed to the subwoofer, the amount in that range is ~0). Subwoofers (designed for 15-200Hz) likely have similar artifacts but it's probably more in the 0-10Hz range though, which is generally NOT considered audible (you can physically feel it though). 

 

 

On 3/24/2024 at 1:25 AM, Motifator said:

There's actually a terminological term to that, bass reflex or ported out or something, not on top of my head. But yeah, bass to the rear is what I prefer.

Usually when the bass hits the wall, the speakers tend to have more spacing for bigger tweeters up front, etc.

The terminology and use in this particular quote most applies to bookshelf or tower speakers more so than subwoofers. 

Unless you're making the subwoofer yourself you don't really need to worry about the port. For most people the DIY route loses out to just buying used though. 
https://en.wikipedia.org/wiki/Bass_reflex