I tried to find the comment where we discussed bass in a room, I pointed out something that you agreed to, the idea of there being spaces in the rooms bass response, as in, areas where the room isn't in a mode and those areas being easier to locate bass due to higher levels of direct sound vs indirect. The shorter the path to the ear, the better, is what I think. I think that side firing woofers will have a stronger transition leaving and entering the multiple bass modes in the room. I think a forward firing source will have a better response than side firing, belwo the shcroeder. I think the side firing woofers will sound wider. I think most of the wise tails about bass not being locatable are false, within the room. The wise tails about being able to fool the ear by using the vertical axis....thats untrue as well, it is better, but obviously there is room for improvement! On a certain level I think we hear everything, not literally, but just more so than the average... I guess we, are the critical listeners. Whats funny is, you are much more likely to fool your perception, by splitting down the vertical axis (2way 3way etc) or any non co-located bass source.....by keep your head in a vice listening. As soon as you turn your head, or twist your head putting one ear above the other....the image falls apart even more.
Fullrange, Coaxial, and finally, Synergy, represent a desire to remove a certain type of distortion which is a deviation from the original signal, displaying non separated images, that are being separated via X and Y axis and reassemble at a listening point.
Believing all that, whether true or not, leads me to be extremely weary towards side firing woofers.
I due believe in the power 1/4Wl summation.....and as long as the wavelength is between the woofers are longer than the separation of the woofers, it seems like it should be convincing still.....Yet my woofers are 32 inches apart, leaving coupling to cutoff at 108hz and above....So I couldn't use 2 side firing 18's in a two way to 200hz...... If i keep the 15" on top, I could have coupling between the 15 and 18s which once again, in my opinion, is the top shelf of summation let alone efficiency. Side firing woofer with this wide baffle I have would not work.
If I use the PPSL as a lower for a 2 way crossed at 200hz all three drivers are coupled at XO...top shelf of summation.
Maybe the PPSL is only useful in certain situations. Summation has kinda piqued my interest and I want to see what type of SQ is had by having a large amount of SD and mouth area coupled together. Though, in the same breath, I noticed that the midwoofer seemed somewhat redundant and a step backwards to SQ, due to headroom being so high already and SQ appearing equal at the midwoofer and ppsl, 200hz and the PPSL having higher SQ as things went lower.
I honestly think that a horn on top of the PPSL crossed at 200hz is a great thing to listen to. its just that theres room for more woofers, in order to have the box lift the horn to ear height, so why not. The redundant sources theoretically will improve FR, at the cost, of the Image being spread father apart.
Fullrange, Coaxial, and finally, Synergy, represent a desire to remove a certain type of distortion which is a deviation from the original signal, displaying non separated images, that are being separated via X and Y axis and reassemble at a listening point.
Believing all that, whether true or not, leads me to be extremely weary towards side firing woofers.
I due believe in the power 1/4Wl summation.....and as long as the wavelength is between the woofers are longer than the separation of the woofers, it seems like it should be convincing still.....Yet my woofers are 32 inches apart, leaving coupling to cutoff at 108hz and above....So I couldn't use 2 side firing 18's in a two way to 200hz...... If i keep the 15" on top, I could have coupling between the 15 and 18s which once again, in my opinion, is the top shelf of summation let alone efficiency. Side firing woofer with this wide baffle I have would not work.
If I use the PPSL as a lower for a 2 way crossed at 200hz all three drivers are coupled at XO...top shelf of summation.
Maybe the PPSL is only useful in certain situations. Summation has kinda piqued my interest and I want to see what type of SQ is had by having a large amount of SD and mouth area coupled together. Though, in the same breath, I noticed that the midwoofer seemed somewhat redundant and a step backwards to SQ, due to headroom being so high already and SQ appearing equal at the midwoofer and ppsl, 200hz and the PPSL having higher SQ as things went lower.
I honestly think that a horn on top of the PPSL crossed at 200hz is a great thing to listen to. its just that theres room for more woofers, in order to have the box lift the horn to ear height, so why not. The redundant sources theoretically will improve FR, at the cost, of the Image being spread father apart.
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Sounds like you have convinced yourself "whether true or not." I remain unconvinced.
Your arguments are a mixture of HF and LF effects which are nothing alike. "Image" is a HF effect.
There is no spot in a room "where the room isn't in a mode." There are spots where some mode is at an antinode, but the other modes will not be.
Your arguments are a mixture of HF and LF effects which are nothing alike. "Image" is a HF effect.
There is no spot in a room "where the room isn't in a mode." There are spots where some mode is at an antinode, but the other modes will not be.
Anyone have the technical definition?
"the acoustic image is not to be confused with sound, as it is, like the concept, psychic and not physical. It is the image we make of the sound in our brain."
The above is towards my way of thinking but isn't limited by frequency 🤷♂️. Is there an official definition?
I can hear bass mid and treble at various degrees as opposed to view angle of my head on all axi's.
You can put a bass source, within the close distance that I use, And I can look straight at it with my eyes closed.
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"Image" is an audio term that is strongly connected with the psychoacoustic term "localization".
Localization has been studied extensively most notably by Blauert in "Spatial Hearing." It depends on two factors; the first is the interaural level difference, and the second is the interaural time/phase difference. Now at LFs there cannot be any level differences between the ears and the phase difference is miniscule. That means that at LFs localization ability has to be zero. It has a peak in the 2-4 kHz range. Hence it is only logical to surmise that it rises steadily to the 3 kHz region and then falls off. This means that the HFs dominate our ability to localize sound and hence image.
The exact nature of the localization dependence on frequency has not been studied to my knowledge. The rise from LF could be linear or quadratic.
Localization has been studied extensively most notably by Blauert in "Spatial Hearing." It depends on two factors; the first is the interaural level difference, and the second is the interaural time/phase difference. Now at LFs there cannot be any level differences between the ears and the phase difference is miniscule. That means that at LFs localization ability has to be zero. It has a peak in the 2-4 kHz range. Hence it is only logical to surmise that it rises steadily to the 3 kHz region and then falls off. This means that the HFs dominate our ability to localize sound and hence image.
The exact nature of the localization dependence on frequency has not been studied to my knowledge. The rise from LF could be linear or quadratic.
I picture a separated response that is the rooms. I understand this response is different for various source and listener locations. Like a plus or minus to the original signal from the loudspeaker. It might look like this;
As the bass signal moves in between the peaks and troughs of the room, the direct vs indirect sound levels change, there are parts of the spectrum (not the room) where the frequency being played is not in a mode and bass is easily locatable. Its actually when the frequency being played is directly within one of the rooms Peaks, that bass sounds like it coming from every where....Mind you, I get to turn my head anyway I please to locate it.
So how am I doing it? I can tell theres no sub bass coming from my mid.....I can tell theres no sub bass coming from my tweeter horn....I can tell that sub bass is on the floor. I can tell the sub bass is not coming a speaker placed behind. There's some type of intensity that I can perceive and it allows to locate where the bass is coming from. Like I said before, it seems that it is only when the frequency is at a bass note that excites the room intensely does the source disappear and pressure seem to come from everywhere, or even one side of the room vs the other.....What about the bass content that isn't directly within a node
Is there an experiment you'd like to me to try???
Thinking off the top of my head, I would surmise for my experiences that I could put the subwoofer on the left side of me, and you could never convince me that it was any other place, but to the left of me, when the sub is only 54" away...unless, the room had one those crazy intense room modes and we placed the signal there... even then I feel like with some head turns in pitch twist of my head. I could probably figure it out. On second thought, Modes do get crazy, in a room... I once found one mode where if I moved my head towards the rear boundary while keeping sub to one side, the bass was louder on the other....
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To say that the whole spectrum of bass is going to be unlocalized at every listening vs source position, to me, is false
I cant disagree with reality , I'm sitting in front of my sub playing signals currently... and it's definitely locatable lol. Depending on frequency and head position...
At certain frequencies I can move my head and bass seems to come from another part of the room, and then move my head again and it sounds like its coming from the direction of the speaker
I'm sitting at just about whatever you call that transition Where if I get any closer all the sounds always sound like they are coming from the speaker. Is that the direct field? Or past the critical point?
At 22hz the localization becomes harder...but I know I have a large mode down there as well
At 40-50Hz there's these phase changes as I swivel my head from left to right and I can easily locate the sub
At 60 Hz, the phase changes, it seems to have died down as I turn with my head, but it's obvious that the sound is loudest with my ear pointing at one particular point in space on the x axis...
I think I'm just too close for me to be fooled by the room.... i'm listening at about 45 inches in if I lean into about 34" a stronge transition happens and the room is drowned out.
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I feel like there's a strong connection between what I'm able to do and listening distance if I move my listening distance back things get confused real quickly
45" - I can localize at 44hz
80" from sub, 50" from backwall....44hz is literally everywhere...like inside of my brain even.... thats what I call being directly within a strong mode... like the type mode that vibrates your sinuses, if loud enough
45" - I can localize at 44hz
80" from sub, 50" from backwall....44hz is literally everywhere...like inside of my brain even.... thats what I call being directly within a strong mode... like the type mode that vibrates your sinuses, if loud enough
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Below which certain frequency? Are we talking anechoic or echoic conditions? At which proximities? 1m or 10m? Source location? Room size?
Heres a good one... at my 45" listening distance, playing 44hz... theres a 10db difference between the left and right ear.... right ear facing the sub.
This will be a frequency that is very easy to locate the sub
At 30hz theres an obvious mode, left is up 1-2db over right... if I move back to the position 80 inches away from the sub 50 inches away from the wall the bass gets loudest and sounds like it's literally coming from everywhere
I feel like through most of the bass spectrum I could probably find a listening position in the room where the bass is 100% not locatable, but I am not convinced that this trait is possible at all bass frequencies at just one listening position, in every room for every source position, etc.
This will be a frequency that is very easy to locate the sub
At 30hz theres an obvious mode, left is up 1-2db over right... if I move back to the position 80 inches away from the sub 50 inches away from the wall the bass gets loudest and sounds like it's literally coming from everywhere
I feel like through most of the bass spectrum I could probably find a listening position in the room where the bass is 100% not locatable, but I am not convinced that this trait is possible at all bass frequencies at just one listening position, in every room for every source position, etc.
Localizing a single tone is a best case scenario. With musical sources our dominate localization comes from the HFs. There may be many reasons that you feel that you can localize LFs (like the fact that you know where the source is,) but the science says that you cannot. If your in the extreme near field then that's one way, and another is the harmonics in the signal. 2nd and 3rd may not be very audible in a musical signal, but for a pure tone it would only take a very low level to yield a localization cue.
There is no sharp cutoff (as I said before) and it all depends on the source location, the room and distance. The fact remains that localization of musical sources is dominated by the HFs.
I can agree with the points surrounding "best scenario" and "Dominanted by HF".
I wouldn't think theres a sharp cutoff of effect, based on my experiences, either... I also considered the idea that I literally mentally know where the subwoofer is... I tried standing up and turning in circles for a good while, but my ability to orientate was too strong lol!
One thing we might readily agree on is that when 2 drivers are coupled, within 1/4WL, this is a best case scenario of summation.
I wouldn't think theres a sharp cutoff of effect, based on my experiences, either... I also considered the idea that I literally mentally know where the subwoofer is... I tried standing up and turning in circles for a good while, but my ability to orientate was too strong lol!
One thing we might readily agree on is that when 2 drivers are coupled, within 1/4WL, this is a best case scenario of summation.
Binaural localization has many mechanisms - phase and spl difference and unconscious head movements to improve those. Room reflections often amplify lateral phase cues, or even make phantom sources.
Music and speech is always mix of various frequencies and instruments' sound has huge content of harmonics. Everyone can test how difficult localization of sine waves is! Use REW and play only L or R channel, eyes closed and a friend changing source!
http://www.davidgriesinger.com/ http://www.davidgriesinger.com/IOA/IOA_2018.pptx
Music and speech is always mix of various frequencies and instruments' sound has huge content of harmonics. Everyone can test how difficult localization of sine waves is! Use REW and play only L or R channel, eyes closed and a friend changing source!
http://www.davidgriesinger.com/ http://www.davidgriesinger.com/IOA/IOA_2018.pptx