Bass direction is audible

[AdamG]

Yeah but an earthquake literally is all around you. Doesn’t matter where the epicenter was. The ground is undulating all around you.

Good point. But an Earthquake is not sound. The ground moving is not sound. The sound is created by the earthquake but the ground moving is due to shifting plates.

I can hear the bass in the Kitchen and front bedroom and garage which are the farthest rooms from the Sub. But when far away I can’t tell what direction it is coming from as it feels like it’s coming from all directions at once. I only feel a sense of direction when I am within 10 feet or so from the front of the Ported Subs. This is just my personal experience and I know my room and furnishings all play into how the bass waves move in the room. My brain knows the the size of the sound wave of 20Hz is about 60’ feet long give or take. That means that the sound hits everything in the room up to 60 feet away at exactly the same moment. Maybe the closer to the source reduces the amount of reflected energy and permits the mind to sense the source? It’s not port wind because at 20Hz the speaker is barely moving (they are tuned to 12Hz). It’s a mind game.

 

[Cbdb2]

A 2 minute test. Play some music, turn your mains off and leave hour subs on. Stand near your listening position, close your eyes and spin around 5 times. Can you point to your sub? Then its directional. I find you need a low f (50ish) steep filter or its localizable (is that a word?) Your results may vary.
We are 15db more sensitive to 90hz (the 3rd harmonic ) than to 30hz and localizing 90hz is easy, the reason for a steep LP filter, and the need for low distortion. If your sub has 1% of 3rd HD at 30hz the 90hz distortion is almost as "loud" as the 30hz
I believe this is a reason some people think they can hear 20hz, when what they hear is the distortion or a sub/woofer resonance.

 

[Cbdb2]

. That means that the sound hits everything in the room up to 60 feet away at exactly the same moment. Maybe the closer to the source reduces the amount of reflected energy and permits the mind to sense the source?

Ah no. The sound hits everything thats the same distance from the speaker at the same time, not everything in the room.
Low freqs (<about 200hz depending on your room) don't reflect of of walls like higher freqs there all about room modes.

 

[OCA]

Interestingly, in my case, what sounded best and surprisingly measured best at the MLP was front stage L&R subs just inside! the the Main L&R front speakers.
You can find my latest system setup here, if you would be interested. My heavy-large L&R subwoofers, YAMAHA YST-SW1000, mainly cover 16 Hz to 55 Hz.

Spoiler

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Front wall placement rules...But why exactly did you need to add 30cm woofer subs to 3-way speakers with 30cm woofers?

 

[JSmith]

Stand near your listening position, close your eyes and spin around 5 times.

Pin the tail on the sub?


JSmith

 

[Sacha]

I can absolutely localize a sub in my room with the standard 85hz crossover. Maybe partly because my room is heavily treated? Nonetheless when I got two subs (placed on each side) they melded together and create a low end 'phantom center' and it's glorious. If it's imagination, bias etc. I have to live with that perception every time I listen so I'd rather enjoy it if I can.

 

[restorer-john]

To me, subwoofers are absolutely directional and betray their position regardless of their level and Fc. In my experience, most subwoofers also have considerable residual noise.

Subwoofer/s in a room, are only acceptable if the subwoofers are placed under the mains or extremely close to the mains. Mostly, my subwoofers sit gathering dust. They have all been a waste of money in reality as my preference is listening to my many loudspeakers full range, regardless of their capabilities.

 

[bmc0]

why exactly did you need to add 30cm woofer subs to 3-way speakers with 30cm woofers?

Diameter does not by itself determine volume displacement capability or usable frequency range.

 

[Justdafactsmaam]

Iit's a conclusion arrived at by "reading the paper carefully, paying attention to the test conditions, then considering how the results may or may not be applicable to other situations."

How is that 'jumping'?

Start at “considering” and go from there. Without further real investigation of thresholds of audibility of bass directionality and levels of room reverb anything you “consider” ultimately is speculative. Any conclusions drawn from such speculation is a leap

 

[Justdafactsmaam]

Good point. But an Earthquake is not sound. The ground moving is not sound. The sound is created by the earthquake but the ground moving is due to shifting plates.

True

I can hear the bass in the Kitchen and front bedroom and garage which are the farthest rooms from the Sub. But when far away I can’t tell what direction it is coming from as it feels like it’s coming from all directions at once.

Yeah. That ain’t just a bass thing. The farther the sound source gets the more you lose spatial cues

I only feel a sense of direction when I am within 10 feet or so from the front of the Ported Subs. This is just my personal experience and I know my room and furnishings all play into how the bass waves move in the room.

Yes. It’s anecdotal.

My brain knows the the size of the sound wave of 20Hz is about 60’ feet long give or take. That means that the sound hits everything in the room up to 60 feet away at exactly the same moment.

I think that’s true regardless of the wavelength. I could be wrong but I think the speed of audible sound through air is pretty uniform across the spectrum. Certainly at 60 feet it’s quite uniform

Maybe the closer to the source reduces the amount of reflected energy and permits the mind to sense the source? It’s not port wind because at 20Hz the speaker is barely moving (they are tuned to 12Hz). It’s a mind game.

There’s a tremendous amount of research on the perception of spatial audio. The thresholds of perceptual directionality of bass is not fully agreed upon. That’s by experts doing serious research. This paper adds to the subject.

I don’t think any of our anecdotes add anything reliable.

I do see some folks writing the study off as irrelevant because the results were wrought in an anechoic chamber.

I think that’s a convenient assumption.

 

[jhaider]

I only feel a sense of direction when I am within 10 feet or so from the front of the Ported Subs. This is just my personal experience and I know my room and furnishings all play into how the bass waves move in the room. My brain knows the the size of the sound wave of 20Hz is about 60’ feet long give or take. That means that the sound hits everything in the room up to 60 feet away at exactly the same moment. Maybe the closer to the source reduces the amount of reflected energy and permits the mind to sense the source? It’s not port wind because at 20Hz the speaker is barely moving (they are tuned to 12Hz). It’s a mind game.

That reads like port (pipe) resonance issues to me. Doesn’t have anything to do with “wind,” just the fact that there’s a pipe tuned to a certain resonance and thus to also produce overtones at lower level.

 

[Curvature]

Why the study is relevant to home audio, outside of anecdata:

There is a study by Fazenda which shows that the most preferred subwoofer setup is the source-sink method because of low decay times.

We are also have convenient, relatively, electronic treatment (PSI AVAA) and digital impulse correction (Dirac ART). Both things are locked behind lots of dollars, as are double bass array setups, but they are available.

So, and this is speculation, if our hearing is capable of doing a thing, bass localization, and there are several things, like room modal behaviour, speaker/sub placement and capability, media/recording related issues (bass management, psychoacoustic compression in codecs) that prevent our ability from being used, then it must be very exciting for our hearing to finally exercise bass localization when all the circumstances are right.

The main application I thought of with this new study is that the ideal crossover frequency should 60Hz and below. However, the main complication is the room situation. Normal modal behavior makes the recommendation irrelevant, which further suggests that any recommendations we have about optimal system setup are within certain psychoacoustic circumstances, and that treating your room will impact thresholds, which will change what does and doesn't matter to some degree.

I would also note, separately, that the older studies about sub crossover frequencies asked about localizability, not if bass was localizable, but specifically if the subwoofer was.

 

[jhaider]

I concede that a single sub + EQ can give satisfactory results in one listening location,

That should be true. I’ve had some weird experiences though. Most recently, I kind of fell into a really, really high performance sub. With nowhere else to use it I put it in my desktop system. Previously I had used three teeny tiny subs (Sonance D8). I EQed the response and used a 5th order 80 Hz filter with the mains (Neumann KH 120 II). To my surprise, the soundstage seemed less reach-out-and-touch it than with three subs in different directions at different heights. I added back one of the little D8s in front and slipped a Paradigm MilleniaSub (another modest “lifestyle” thing) behind me, and while I haven’t had the chance to fine tune xover levels and delays to smooth out the FR or tune at all for standing position - thaf solidity is back. Even though now the 15” super monster is throttled by sharing duties with two lunchboxes.

Expectation bias? Be silly to rule that out. But this is I think the second such experience I’ve had with multisubs offering perceived benefits even for a single seated position.

I have distributed multi-sub customers who use crossover frequencies an octave or more north of the 80 Hz "upper limit", in situations where they have about two octaves of overlap from which to choose the best-sounding crossover frequency. These are customers who use CLIO and/or REW.

FWIW, my starting point when deploying multisubs is usually 125 Hz - but being dogmatic (assuming you have sufficient headroom on both sides) is dumb. Right now our main system (3 subs, front corners + left side nearfield-ish) is at 70 Hz. Getting rid of the tyranny of bass management is one thing that excited me about Dirac ART.

 

[Keith_W]

All of you guys who assert that subwoofer direction is audible need to be more specific. (1) how high is your sub crossed over? (2) are you sure your sub is not distorting? Don't forget that the 1st harmonic of 60Hz is 120Hz, and I would not be surprised if you can hear where your sub is if it's making a 120Hz harmonic.

 

[Thomas_A]

Test your crossovers!

 

[dlaloum]

All of you guys who assert that subwoofer direction is audible need to be more specific. (1) how high is your sub crossed over? (2) are you sure your sub is not distorting? Don't forget that the 1st harmonic of 60Hz is 120Hz, and I would not be surprised if you can hear where your sub is if it's making a 120Hz harmonic.

One of the issues often overlooked, is that Subs moved from being primarily music oriented in the 1980's and 1990's, to now being primarily Home Theatre oriented...

With that change came a shift from low distortion being the top priority, to high SPL's being the top priority

I think it is particularly relevant in a marketplace where the focus on SPL's has allowed higher THD's to become acceptable... and perhaps (measurement would obviously be required) - this observation about Harmonics identifying sub location, becomes highly relevant...

Keeping in mind that speakers that can achieve distortion of 0.5% THD are considered excellent (even SOTA) - whereas Subs are given a pass mark with 10% THD !!!

The HT LFE channel isn't intended to be localisable, it is an "effects" channel, and should be providing pretty much the same effect throughout the listening area - hence multiple subs and various optimisations to ensure a single cohesive experience throughout the listening space...

Music is a different beast.... 10% THD at 30Hz.... that would be quite a substantial 2nd harmonic at 60, 3rd at 120Hz... these should definitely be audible and localisable.

 

[dualazmak]

Front wall placement rules...But why exactly did you need to add 30cm woofer subs to 3-way speakers with 30cm woofers?

As for one of the main reasons, you would please refer to my post here.
- Reproduction and listening/hearing/feeling sensations to 16 Hz (organ) sound with my DSP-based multichannel multi-SP-driver multi-amplifier fully active stereo audio system having big-heavy active L&R sub-woofers: #782

Another my post here would be also of your reference:
- A nice smooth-jazz album for bass (low Fq) and higher Fq tonality check and tuning: #63

These posts would be also of your interest, I hope:
- Measurement of transient characteristics of Yamaha 30 cm woofer JA-3058 in sealed cabinet and Yamaha active sub-woofer YST-SW1000: #495, #497, #503, #507

And, this thread too would be your interest, I assume:
- An Attempt Sharing Reference Quality Music Playlist: at least a portion and/or whole track being analyzed by 3D color spectrum of Adobe Audition

 

[OCA]

As for one of the main reasons, you would please refer to my post here.
- Reproduction and listening/hearing/feeling sensations to 16 Hz (organ) sound with my DSP-based multichannel multi-SP-driver multi-amplifier fully active stereo audio system having big-heavy active L&R sub-woofers: #782

Another my post here would be also of your reference:
- A nice smooth-jazz album for bass (low Fq) and higher Fq tonality check and tuning: #63

These posts would be also of your interest, I hope:
- Measurement of transient characteristics of Yamaha 30 cm woofer JA-3058 in sealed cabinet and Yamaha active sub-woofer YST-SW1000: #495, #497, #503, #507

And, this thread too would be your interest, I assume:
- An Attempt Sharing Reference Quality Music Playlist: at least a portion and/or whole track being analyzed by 3D color spectrum of Adobe Audition

Do you have the measured (not calculated) responses NF or at the LP? Are you using 96kHz sampling rate to apply these 25kHz brickwall filters?

 

[restorer-john]

Keeping in mind that speakers that can achieve distortion of 0.5% THD are considered excellent (even SOTA) - whereas Subs are given a pass mark with 10% THD !!!

Exactly. My current mains have twin woofers which cover just one octave and are completely crossed over by 115Hz. Their THD was measured (reviewed) at 0.9% at 110Hz and 1.5% at 42Hz. 9% THD at 30Hz. They have way less inherent distortion than many expensive powered subwoofers, so I have little to gain, and plenty to lose.

 

[Sokel]

What is probably contributing to sub's distortion is amp's power/quality.
I know I'm only one sample but see what happens when I swap the most powerful 1200as to the best measuring 300a at the exact same conditions.
(my speakers go to 32Hz,no more,so ignore lower)



1200as lows




300a lows

Before jumping to conclusions about power,note that at this level only a few watts are needed,both are more than adequate on paper.
Is just that the one does way better than the other.

(Amir measured an implementation of 1200as and it did excellent at 20Hz,despite the "audiophile" buffer at it's front end,that's why the THD+N vs Freq is one of the best measurements)

Edit:Typos