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2 minutes ago, davewantsmoore said:

 

Yes... (that's right, but)  I don't think Brian mean it like that.

 

He just means the example where ..... you have no sound .... and then "suddenly" you have a LF sound.  (eg. where he says "the first hit"   

OK - good luck to @BioBrian, @frednork localising that in a room...below the transition (modal) region of a room down into the pressure region of  a room.

 

Mike

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Just a quick announcement that twins were painlessly born today, to a badly-presented but relieved BioBrian and his wonderful StereoNetter cohorts. I'd really like to gratuitously thank all staff, but

It's an odd experience when I find someone referring to something I wrote that I can't remember.   When you compare different kinds of subs, there are two experiences. The first is the easy

Both boxes now all trimmed, ready for final sand and varnish. Don't think I'll need DuraTex after all...   Worst problem has been lack of handles to move them.   110 kg each, so wi

10 minutes ago, davewantsmoore said:

If it contains only low frequencies, then it has (practically) identical level and phase in both ears.    Even if the source was directly to his left (for example).

Level is not important, as long as it's audible. It will be in the same phase, yes. But my personal interest is in time of arrival, and our sensory perception of that.

 

Whether a single, or randomly executed, low frequency pulse (OK, not a common occurrence) is heard first by one ear (or other relevant body part) is the question. I don't know the research that is being referred to, and suspect it's not entirely relevant to this exact question. I would prefer to have us discuss actual experience of the directionality of LF impulses, as @frednork has offered us.

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24 minutes ago, almikel said:

OK - good luck to @BioBrian, @frednork localising that in a room...below the transition (modal) region of a room down into the pressure region of  a room.

I'm hoping we can get somewhere without luck. The implications are potentially significant.

 

Any chance of doing a single 24 Hz pulse into 1 of your TD 18s?

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1 minute ago, BioBrian said:

Any chance of doing a single 24 Hz pulse into 1 of your TD 18s?

I don't run my TD18s down to 24Hz (I high pass them at 60Hz) - and the concept of a "pulse" implies higher frequencies.

 

Good idea though - they're setup as stereo...but 24Hz is a big stretch...major EQ would be required to get that low in their small boxes (natural roll-off is around 100Hz)...

...that's why I added a sub...EQ can only get you so far...

 

Happy to run some experiments on my TD18s at 70Hz or so...ie within their passband...what do you propose?

 

Mike

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9 hours ago, davewantsmoore said:

things like THD, and ETC

whats ETC?

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10 hours ago, BioBrian said:

Level is not important, as long as it's audible. It will be in the same phase, yes. But my personal interest is in time of arrival, and our sensory perception of that.

 

Level would be important..... but the level in your left ear vs the right ear is always equal at these frequencies .... no matter anything to do with where/how the sound originated from.   It is the same for phase.... there is no phase difference between your ears.

 

I understand what you are saying.....   ie. If you have one bass sound arriving (from the left speaker) ... and then a delay... and then another bass sound (from the right speaker) ..... what happens?

 

Neither are perceived as coming from a location.... because (as above) each wave is perceived in both ears with equal phase and level.

 

If the delay between each sound (from the L and from the R speaker) is small enough (which is still large) .... and the frequency is equal ..... then it's all just sums together.

 

If the time delay, and/or frequency difference is large enough ...... then this creates intermodulation effects.... which you can perceive.

 

This can translate into spatial perception (as in audio with and without such effects can be though to move, or swim, or sound with a certain 3d-ness to it) ..... but before you say "ah ha!" ..... this isn't "locating the subwoofer".    It' a virtual effect.... and isn't a case of "I can hear the subwoofer is over there"   (the identical effect could be recreated with the subwoofer in a completely different location).

 

 

10 hours ago, BioBrian said:

Whether a single, or randomly executed, low frequency pulse (OK, not a common occurrence)

 

It depends what you mean by "pulse".   There is essentiall no such thing.

 

Let;s take a 40hz "pulse" ..... we have no sound.... and then suddently we have sound.   The "first hit" so to speak.

 

We have nothing.... and then the pressure begins to rise.   It continues to rise for a half a wavelength... ie. 12.5 milliseconds.

This is slow.   There is no "wavefront which hits you".

 

 

If you are thinking of a sound which does "pulse".... ie. "hit" you.     This sound contrain high frequencies.   You can hear the direction of these.

 

These are common.... much more common than you might imagine.    That is because the shorter the sound, the more frequencies it contains from the entire spectrum.

 

The shortest possible pulse contains every single frequency.    1hz, 2hz, 3hz, 3000hz, 300khz.... etc.

 

The longest possible pulse (eg. an "infinitely" long sound) ... contains one single frequency only.

 

A short ish sound has lots of frequencies .... and lots of high frequencies (these are what makes it "stop", by interfering with the longer bits thay would otherwise continue onwards).

 

10 hours ago, BioBrian said:

is heard first by one ear (or other relevant body part) is the question.

 

It arrives at one ear first (of course this is always true) .... but the distance to the second ear is small.    As a fraction of the wavelength in question it is (super) small.

 

So.... No.    It isn't "heard" in one ear first.    Because while the time delay between the ears (the speed of sound and your head size) is there..... the phase of the time delayed sound reaching the other ear is not changed enough to be perceived.

 

10 hours ago, BioBrian said:

I don't know the research that is being referred to, and suspect it's not entirely relevant to this exact question.

I understand your question.... it is relevant.

 

10 hours ago, BioBrian said:

I would prefer to have us discuss actual experience of the directionality of LF impulses, as @frednork has offered us.

I don't doubt his or your experience was exactly what you say it was.

 

... and I'm discussing it.   There is another reason for what you experienced than what you think caused it.

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2 hours ago, frednork said:

whats ETC?

 

Energy time curve.  Are you using REW? .... I should be an obvious tab.

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10 hours ago, BioBrian said:

Any chance of doing a single 24 Hz pulse into 1 of your TD 18s?

 

It's very important to clarify what you mean by this.

 

If you want the tone to stop or start more abruptly than the "gentle" way a 24hz tone must start an stop ...... then this implies the precense of high frequencies.

 

If you want a short "sharp" crack/bang/pulse .... then this implies LOTS of high frequencies.   This might or might not be filtered out adequately by the low pass filter of the subwoofer.

 

... but to the degree that they are not..... in a regular system (where main speakers are also playing) .... the main speakers are significantly louder, which mean they completely dominate the location cues.

 

 

I hope I'm not making you sick.... I honestly wouldn't bother writting all this if I wasn't trying to help.

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9 hours ago, almikel said:

Happy to run some experiments on my TD18s at 70Hz or so...ie within their passband...what do you propose?

 

You will need a very steep filter.    Small amount of low frequencies could cause the subwoofer to be localised when it is playing on it's own.     As in the previous comment.... if you add main speakers into that mix (which are significantly louder) they dominate.... so it's not relevant generally.

 

... but the sort of filter that Fred used should be fine.... but you would also want to check the output to be sure.

 

 

As I've said a few times.... at the risk of being blunt (ore than usual, lol) ..... if we get these results where it's audible ..... then there is an explanation that isn't "bass is directional"....  Or said another way, if we want to conclude that every text book on physics and hearing are fundamentally wrong.... and that all the well controlled experiments that have shown it to be true over the past century missed demonstrating it ....  then you will have to demonstrate it wasn't something else first before you collect your nobel prize.... and there's lots of things it could be.

 

Especially when we get results like Brian did where a LFE sub crossed over, got a very very different sound "missing bass" etc.   It's obviously not setup right.   We've all seen the measurements of the gesties and the main speakers ..... they weren't flat (so will be different to what the oppo targeted) .... and they are more sources in the room, so there's going to be a different modal distribution of sound.   Of course it gave a really different result... but you can fix that   (and it isn't becuase stereo bass, or timing bass, or anything like that).

 

For me, I can locate my subwoofers with the right test...... it is things in the room rattling differently.  Hard to tell as the rattles are a lot shorter (normally, lol) than the woofer response.    Outside, no.

 

I could locate my mini (6") tapped horn outside... but that turned out to be narrow bands of distortion.

 

FWIW... If we are perceiving direction bass.... then if it were me, I'd be interested to figure out why (and how I could "fix" anything which was wrong) ..... not "we've made a new discovery" (LOL).   Like when Brian, your Oppo "didn't work" (missing bass, etc.) ..... not draw a conclusion as to "why".... but figure out what the real difference was (and find the real, actual cause) .... and hopefully resolve it.   <shrug>

As I said, I wouldn't bother with any/much of this, if I wasn't really trying to help someone.

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22 minutes ago, davewantsmoore said:

 

Energy time curve.  Are you using REW? .... I should be an obvious tab.

Ahh, Dr. Google to the rescue, in REW it is called impulse

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15 minutes ago, frednork said:

Ahh, Dr. Google to the rescue, in REW it is called impulse

Oh sorry yeah , it's a tick box under impulse.  <smh>

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Posted (edited)
On 05/05/2021 at 11:06 AM, davewantsmoore said:

This doesn't exist until someone demonstrates that it does.

 

The wind blows on my face and I know the direction from which it comes.  Perhaps localisation of bass frequencies is a similar thing.  When I am in the chair and listening I can feel my shirt and chair and sometimes the floor vibrating (needs to be really loud and really low for that last one).  That is what I meant by tactile.

 

Anyway, I'm not arguing and have not had time to read through the rest of the thread up to this point so may have missed some other discussion on the point.

Edited by acg
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33 minutes ago, davewantsmoore said:

As I said, I wouldn't bother with any/much of this, if I wasn't really trying to help someone.

 

If it is a bother to you, stop trying to "help".

 

Don't worry, the world still turns without you.

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2 hours ago, davewantsmoore said:

I hope I'm not making you sick.... I honestly wouldn't bother writting all this if I wasn't trying to help.

 

I appreciate your patience again, and obvious care taken to understand the workings of my system. Some snippets appear, every so often, that help complete the picture for me but I confess to having low tolerance to undue repetition, especially when I think it's wrong 🙂.

 

TBH I did feel brutalized by your post the other day, just as I thought the thread had wound itself up neatly. I guess you couldn't leave it, as that might be seen as complicity, so I wasn't surprised it came. Sometimes I'm just too delicate to be playing this internet thing, and for some reason you pushed some really ugly buttons for me, which I wasn't prepared for, and it's been hard to pull back onto the road.

 

Just before, I was trying to find any clues from the way whales use LF sonar as navigation. Didn't get anywhere - they apparently use between 30 and 8000 Hz (I had thought it included lower than 20 Hz) - but this noise they make is pretty close to what my brain's been sounding like:

 

https://journeynorth.org/sounds/humpback4_omi.wav

 

I do hope we can make some good progress on the directionality of bass; it's obvious to me that there's more to it than e = mc2, etc.

 

 

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9 minutes ago, BioBrian said:

I confess to having low tolerance to undue repetition, especially when I think it's wrong 🙂.

🤣 I've been told I have a high tolerance (to most things) ..... but I don't like it either  🤣

 

9 minutes ago, BioBrian said:

TBH I did feel brutalized by your post the other day

This wasn' t the intention.....  sometimes I'm a bit to "objective"... but I'm only honestly trying to help.

 

9 minutes ago, BioBrian said:

just as I thought the thread had wound itself up neatly. I guess you couldn't leave it

Dunno... I just a it in the new posts box and replied.

 

9 minutes ago, BioBrian said:

Just before, I was trying to find any clues from the way whales use LF sonar as navigation. Didn't get anywhere - they apparently use between 30 and 8000 Hz (I had thought it included lower than 20 Hz) - but this noise they make is pretty close to what my brain's been sounding like:

 

A whale has a head much larger than a human.... which would give it the ability to hear lower (the distance is larger) .... but sound travels faster in water, so that would undo some of it.

 

In thoery (I'm not 100% sure how wales hear) ... but that's how the waves and distances work.

 

On 01/05/2021 at 12:19 PM, BioBrian said:

The best recordings I've found are recorded in "5.0".

 

I did think about this..... and realised that given that "non-movie" sound standards don;t use a dedicated LF channel of content (ie. in the mix/recording) .......  that you might assume, that is because it's important to send the full range audio (ie. the bass) to each individual speaker.

 

ie.    Something like..... "They tell you to use 5 (or whatever) full range channels, and they have bass in all channels ..... so of source, "bass is directional".... why would they do it otherwise?! 

 

But no.   This is not the reason.

 

If you're interested, I can explain why music is recorded in 5.0 (and other standards have 5.1).    It's not because it's important to send back-left bass to the back-left speaker (for example).

 

... but I won't, if not interested.

 

21 minutes ago, BioBrian said:

it's obvious to me that there's more to it

 

I still don't really understand why you think so.....  aside from you heard it in your system.... but without accounting for any number of things which could have caused it  (the way you describe the result is an immediate tell something is "wrong").

 

Anyways.... I think you know by now not to take that as an "attack".  I'm just suggesting you should focus on it, if you're interested in the things you say you are  :)

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I always run dual subwoofers, for headroom and output down low, but also for the reason that it takes away that persistent thought “does that bass sound like it’s coming from one side?” 

 

 There may be no reason to the rhyme but it lets the mind relax 😂 

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Ok, first results are in. I tried the same as yesterday except this time with a bit of highway star by deep purple. Same thing happened. Then I plonked the mic where i was sitting and moved back a bit. I must admit it was much tougher to determine where it was coming from and there was a bit of that swirling @davewantsmoore was talking about which was weird. Never really noticed that before (but not usually listening to sub 50hz thumps behind my listening position either.)

 

So what I did was use the same filter as shown yesterday and ran a 10-20k sweep to see what it did

Here are the amplitude plots,

2062641242_amplbass.jpg.eb302ff444dcf59e2a5d1b8eaf8fb507.jpg

 

I was wondering what the bump at 90 was so looked at the waterfall plot, dishwasher was on so assume it is probably from that? Anyway whatever it is it is a constant background noise.

780027310_waterfallleft.jpg.1abc0c6b827688e7315c5c40f1e24833.jpg

 

And here is the ETC perhaps Dave you can explain what the ETC shows as I dont really know much about it.

 

52248430_LeftETC.jpg.8fa0cca540aa90f63872c3c3d47b89f2.jpg

 

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13 minutes ago, frednork said:

 

And here is the ETC perhaps Dave you can explain what the ETC shows as I don't really know much about it.

 

52248430_LeftETC.jpg.8fa0cca540aa90f63872c3c3d47b89f2.jpg

 

 

I'd like to know too, Mark.  :thumb:

 

In fact, I don't even know how to get that graph!  :(

 

Andy

 

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Posted (edited)
1 hour ago, andyr said:

 

I'd like to know too, Mark.  :thumb:

 

In fact, I don't even know how to get that graph!  :(

 

Andy

 

Andy ,its just a tick box at the bottom of the impulse page (orange colour)

image.thumb.png.7df0ace9e304b15e6c3ddb0e22d993ec.png

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9 hours ago, frednork said:

 

Andy, it's just a tick box at the bottom of the impulse page (orange colour)

 

image.thumb.png.7df0ace9e304b15e6c3ddb0e22d993ec.png

 

Aah, OK - thanks Mark.

 

And what does the graph tell you?

 

Interestingly, when I select the impulse graph for one of my plots ... I get a very different curve???

 

638421113_SatoriImpulse.thumb.JPG.f12fb464f73d393956ea6b3356100528.JPG

 

I have absolutely no idea what it's trying to tell me!  :(

 

Andy

 

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42 minutes ago, andyr said:

Interestingly, when I select the impulse graph for one of my plots ... I get a very different curve???

 

You're seeing the (normal) impulse of your speaker.... To add the ETC view of the impulse, its a tick box down the bottom.

 

42 minutes ago, andyr said:

I have absolutely no idea what it's trying to tell me!  :(

 

There's a lot of information contained in this chart.... to understand the cause of what is in the chart, you need to read other charts too (eg. frequency and phase responses).

 

What it is showing is:

  • High frequencies out of phase with other high frequencies.....  typical for a large/long panel/ribbon transducer.   Arguably not good, but I think it's one of those things that look terrible on a chart, but aren't so bad in reality.
  • Mid frequencies slightly out of phase/time with high frequencies.
  • A big error around 1khz ... which could be in the XO, or it could (much more likely be) be diffraction.
  • Probably shows things to do with the bass, and with the pre-ringing in the digital converters .... but would have to investigate other charts to be able to say .
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12 hours ago, frednork said:

ETC shows

Shows nothing as expected.    If the first big lump was wonky, then that would be worth looking i

 

12 hours ago, frednork said:

Ok, first results are in. I tried the same as yesterday except this time with a bit of highway star by deep purple. Same thing happened. Then I plonked the mic where i was sitting and moved back a bit. I must admit it was much tougher to determine where it was coming from and there was a bit of that swirling @davewantsmoore was talking about which was weird. Never really noticed that before (but not usually listening to sub 50hz thumps behind my listening position either.)

 

So what I did was use the same filter as shown yesterday and ran a 10-20k sweep to see what it did

Here are the amplitude plots,

 

The 90hz bit, I think you are right about.... but it's all down far enough not to be too worried about ..... but again, if we're going to be drawing conclusions that "bass is directional" (or similar).... that everyone else fundamentally disagrees with (and has proved wrong)... then you'd have to get rid of things like that.    Anyways.

 

At 40-50Hz is a bigger issue (although it looks small).    At 40Hz the difference is 4dB.  This is 250% more energy from the right speaker than the left..... but in hearing terms it is worse than this as we are even more sensitive to level changes in the bass (by about double).   So 4dB is quite significant.

 

That doesn't mean you should be able to "localise" them because of that 4dB..... but, "different" gives rise to all sort of brain/phychoacoustic triggers.... where, "I can tell they are different" .... leads to "I can make a mental map of them" (even if that is "invented").

 

Try fixing the 4dB.

 

Also, what does the waterfall left vs right look like?

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5 minutes ago, frednork said:

forgot THD graphs

 

That seems ok....  are these true levels?  If so, the noise is a bit high.... and you could probably measure a bit louder (80dB peak level isn't particularly loud, for listening level ..... measurements at those levels will sound loud tho).

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1 hour ago, andyr said:

And what does the graph tell you?

 

ETC, shows the SPL plotted vs time.... it's typically used at much higher frequencies and at long windows it shows you reflections from the room, and at low windows it shows you things like resonance or diffraction in a speaker driver or cabinet edge.

 

In this case it was just a very very rudimentary check to see if there wasn't anything major happening in the bass/room which would be audible.

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29 minutes ago, davewantsmoore said:

 

You're seeing the (normal) impulse of your speaker.... To add the ETC view of the impulse, its a tick box down the bottom.

 

 

Aah, OK - thanks, Dave.

 

With just 'ETC' ticked ... the graph looks like this:

 

1862258603_SatoriImpulseETC.thumb.JPG.36cf778403060df70117844d3c70b1fb.JPG

 

 

Is that good ... or bad?  :)

 

You also said:

 

29 minutes ago, davewantsmoore said:

What it is showing is:

  • High frequencies out of phase with other high frequencies.....  typical for a large/long panel/ribbon transducer.   Arguably not good, but I think it's one of those things that look terrible on a chart, but aren't so bad in reality.
  • Mid frequencies slightly out of phase/time with high frequencies.
  • A big error around 1khz ... which could be in the XO, or it could (much more likely be) be diffraction.
  • Probably shows things to do with the bass, and with the pre-ringing in the digital converters .... but would have to investigate other charts to be able to say .

 

Re. my original plot again:

 

2124077385_SatoriImpulse.thumb.JPG.21586ae467360850281fe84781e32d39.JPG

 

 

I'd be grateful if you could tell me:

  1. what told you that the mid frequencies are slightly out of phase/time with high frequencies?
  2. I can't see any mention of frequency on this graph - so what told you there is a big error around 1khz?  (BTW, XOs with these spkrs are at 100Hz and 4kHz ... so the error would seem to be a diffraction artefact - not a XO artefact.)

Thanks,

Andy

 

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49 minutes ago, davewantsmoore said:

Try fixing the 4dB.

 

Also, what does the waterfall left vs right look like?

Will try to fix the 4db. What do you make of my observation that identifying direction was much harder when I moved back a bit. Can position in room change anything?

 

Assume the difference below is due to the house is double brick with wooden floor. The left speaker has a window next to it but right doesnt

ezgif.com-gif-maker.gif.f9541ed070f931223d8d487bd875378e.gif

 

 

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1 hour ago, davewantsmoore said:

 

That seems ok....  are these true levels?  If so, the noise is a bit high.... and you could probably measure a bit louder (80dB peak level isn't particularly loud, for listening level ..... measurements at those levels will sound loud tho).

Its not true, would be around 5db down on that, not sure why the calibration I did has disappeared

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5 hours ago, andyr said:

Is that good ... or bad?  :)

 

There's a big "reflection" (delayed sound) a bit after 1ms.   This means it's coming from the edge of the speaker, or something close to the speaker.    This is bad.

 

Otherwise .... you need to zoom in.   Like, if the first 1ms was taking up the entire chart.

 

5 hours ago, andyr said:
  1. what told you that the mid frequencies are slightly out of phase/time with high frequencies?

 

The bunching up of the impulse response (compared to what it's supposed to look like, a single vertical, infinitely short, pulse) in the first ~0.5ms.... but it's really hard to read of charts like this.... to look at the issue you'd look at an actual magnitude/phase plot, which would show it clearly.

 

5 hours ago, andyr said:
  1. I can't see any mention of frequency on this graph

Time and frequency are just two views of the same thing (time).

 

1ms corresponds to 1khz....  after seeing the ETC, I can see that it's diffraction, which has a path length difference of ~40cm. If this isn't a dimension of your speaker, then there must be something located close by.    You have a big ribbon speaker right? .... It's tough when you have a large/long transducer with a common path length diffraction.

 

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4 hours ago, frednork said:

Its not true, would be around 5db down on that, not sure why the calibration I did has disappeared

 

If you mean it's at 75dB.... then this is pretty quiet for most measurements (I wouldn't worry too much now though).

 

Test signals have less peak/average ratio than music .... so thy'll sound much louder.   About on the verge of "I need to leave the room, or plug my ears" is about right (although that's obviously subjective).

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5 hours ago, frednork said:

Can position in room change anything?

It can dramatically change the response you hear from one (or both, if the room/layout isn't symmetrical) speakers.    So the "something" that you are hearing..... could be more significant from your typical listening position.    You'd have to take a measurement (from "further back") and see.

 

5 hours ago, frednork said:

Assume the difference below is due to the house is double brick with wooden floor. The left speaker has a window next to it but right doesnt

 

Something is popping up at ~150hz in the left speaker..... what happens at higher frequencies?!  Could be many things, but probably isn't audible (especially not if the true level is actually lower than these), plus masking, etc.

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Posted (edited)
3 hours ago, davewantsmoore said:

Something is popping up at ~150hz in the left speaker..... what happens at higher frequencies?!

20-20k left speaker

image.png.6d4a5b6c5d24319cc7c8ffd74769c1b8.png

Edited by frednork
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Thanks for your very interesting input, Dave!  :thumb:

 

Now I asked:  "Is that good ... or bad?"

 

You said:

 

2 hours ago, davewantsmoore said:

There's a big "reflection" (delayed sound) a bit after 1ms.   This means it's coming from the edge of the speaker, or something close to the speaker.    This is bad.

 

Which I can plainly see on the graph.  Now in fact this graph is for my new, minimal, dipoles - not my panels.  The new spkrs have no 'edges' ... but there are 2 things 400-500mm away from the drivers - which may be the cause of this reflection?

 

One thing is one of my Maggie panels - which I thought I had moved sufficiently out of the way; maybe not!!??

The other thing is the benchtop which all my gear rests on.

 

So I will do another REW sweep over the weekend - removing the Maggie panel and seeing if that reflection goes away.  Then I'll post that graph.

 

(Hopefully the reflection will go away - as I can't move the benchtop; or the move the spkrs further away from the benchtop.  :( )

 

2 hours ago, davewantsmoore said:

Otherwise .... you need to zoom in.   Like, if the first 1ms was taking up the entire chart.

 

Here's the graph with the X axis changed:

 

903468007_SatoriImpulseETC4ms.thumb.JPG.4b5656f36d90c109a07a88bcaee9be9d.JPG

 

 

This clearly shows the reflection at about 1,25ms, right?

 

Andy

 

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1 hour ago, andyr said:

One thing is one of my Maggie panels - which I thought I had moved sufficiently out of the way; maybe not!!??

The other thing is the benchtop which all my gear rests on.

 

Ah, yes... I remember you posting about this bench top before..... doesn't seem like a good idea... but rooms are tricky with all the practicalities of life.

 

1 hour ago, andyr said:

Here's the graph with the X axis changed:

Looks ok.

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On 06/05/2021 at 12:12 PM, Auracle said:

 

If it is a bother to you, stop trying to "help".

 

Don't worry, the world still turns without you.

@Auracle - big call - I'd hate for @davewantsmoore to stop offering his "help" - Dave's knowledge and input to SNA has taught me heaps over the years.

 

@davewantsmoore - contrary to @Auracle's post - many on SNA appreciate your posts...please keep posting!

 

Mike

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17 hours ago, almikel said:

@Auracle - big call - I'd hate for @davewantsmoore to stop offering his "help"

 

Hopefully it's obvious that I wasn't trying to frame this as a "bother" to me.

 

I was trying to ensure that people understood that this is geneuine attempt to help (or I wouldn't do it) ...... rather than an attempt to "dominate" or "disparage".

 

But.... we can switch it around and make it into "bother".... and "help".... and make me look like the "bad guy"..... if that makes some people feel better.  ;) 

 

Sad 😅

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On 07/05/2021 at 9:28 AM, davewantsmoore said:

That doesn't mean you should be able to "localise" them because of that 4dB..... but, "different" gives rise to all sort of brain/phychoacoustic triggers....

 

Hi Dave,

 

When I bought my first subwoofer, I thought, knowing the literature, it doesn’t matter where I put it. So I put it on the side wall directly to the left of where I sit. About 2 m from me. Set the AVR to 80 Hz, adjusted level and delay, and started playing music. 

 

Now, I’m not saying I could localise it, but my left ear felt more ‘pressurised’ than my right ear. You know that feeling  that makes you want to hold your nose and ‘push air out through the ears’ to get rid of it? Can happen when you drive up a hill? Yes, that feeling. But only in the ear nearest to the sub. And only when bass was playing.

 

I was surprised and disappointed. The theory wasn’t working in my situation. When I moved the sub to the front wall in the centre of the room, all was well.

 

cheers

Grant

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3 hours ago, Grant Slack said:

I thought, knowing the literature, it doesn’t matter where I put it.

not being able to "localise" the sub and "it doesn't matter where it goes" are 2 very different things.

 

Sub placement is very important to get the best "in room" bass response.

 

Mike 

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Posted (edited)

Thanks @almikel, I should have said, "it doesn't matter which of the recommended positions I put it in", which I did. It was at the null location on the side wall.

 

Also, I was quoting a comment by Dave about locating, by ear, where the sub is, and in that context, the literature seemed to say it doesn't matter where it is placed, you won't be able to locate it by ear when the crossover is around 80 Hz. 

 

I have also used EQ since day 1, which is considered mandatory for sub bass... but really I thought we were talking about locating it by ear, and that was what my story was about. 

 

cheers

Grant

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7 hours ago, Grant Slack said:

I was surprised and disappointed. The theory wasn’t working in my situation. When I moved the sub to the front wall in the centre of the room, all was well.

 

There is another explanation for what you observed which is not "the theory wasn't working".... I mean, sure... you had a sensation in your left ear... I'm not denying that.

 

... but the pressure rise/fall for low frequencies for subwoofer on the hard left is the same in both ears for low frequencies.   There is no "hit from the left", which you don't get from the right (so to speak).

 

Let's flip it around the other way.   If there were some inherent things about "detecting pressure", or "arrival" or whatever about bass ..... then the countless results which have shown that bass does not work like that would be flawed.

 

As I said.... there was something going on.

 

 

I think what many people seem to miss, is that the point of bringing that up isn't "to be right"..... it is because finding and figuring out what that "something else" is..... is often pivotal in building a better playback system.

 

Drawing such conclusions about "how stuff works".... is just overlooking addressing the real problem/solution.    Not suggesting that what you did (move it) isn't a valid solution (you "fixed" it, right?!) .....  but anyways, you get what I mean, I'm sure.

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