Thats kind of back to the previous question. If SPL next door is related to sound power, then you want to do anything that gives you more pressure at the listener location with less total radiated power. I wold have thought that more subs would go in the direction of increasing SPL faster than power?
If 2 subs give you +6dB SPL but only +3 PWL, then thats a help. If you can have subs closer to you and increase your listening position SPL (hence you can turn down the subs a little) thats a help too.
With room modes being what they are, I don't know why nearfield subs isn't discussed.
David S.
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I took numerous measurements today and found that a near field sub needs about 10dB less power to produce the same SPL as a "far field" sub. That's quite a welcome difference.
Weird, isn't it. It's the cheapest, most effective solution for really good bass reproduction, especially in rooms with rigid walls. That kind of quality is usually only available from purpose-built listening rooms.
I've been reading a couple of room/bass related papers by Griesinger and they are very eye opeing.
http://www.davidgriesinger.com/asa05.pdf
"the placement that is optimal for spatial properties might be different than a speaker placement that is optimal for low frequency response smoothness."
His arguement is that flat pressure in the room won't guarantee good LF sound, that LF spaciousness is desirable and it comes from lateral velocity (differential pressure between the ears). Being in the right position relative to the modes can achieve this.
Worth thinking about.
David S.
Single mono dipole? Orientation? What EQ settings did you apply?
Of course not and as I already said, I don't get in-head localization like you do. All I get is deep, clean, tight, fast, articulated, ultra-smooth bass - best signal modulation reproduction
Maybe you're running the sub too high? Or it produces too much noise/distortion.
Didn't you find the smoothness of the frequency response quite enjoyable?
Single mono dipole, main axis towards the head, symmetrically to median plane. EQ was to compensate for the dipole loss. The elelement was 12" Peerless XLS. Low pass between 70-100 Hz, 4th order LR.
Sure the freq response is good as it is with head phones, but just on the wrong side of the skull..
Nearfield certainly reduces the effort to achieve SPL, but it comes with too heavy other penalties like you have to bolt your head to the chair.
I like to listen in various locations in my room. This is why I went for the my single speaker stereo in the first place.
- Elias
Actually, I was thinking about how multiple subs can be used to cancel modes, which actually leads to a decrease in overall sound level at the lowest frequencies. So, more power is radiated, but standing waves are diminished. This means that also at the room-boundaries there'll be less severe peaks in pressure.
That is what I've been saying all the time from the beginning of this thread 3 years ago
- Elias
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For bass perception body is needed more than ears. And since bass without higher frequencies does not exist in nature it has to be phase coherent. I have subwoofer historically behind my left shoulder, like 3 meters from the seating position is opening in the floor, and despite it works below 40 Hz it is annoying to feel that it fires from the rear left corner. Also since cones generate distortions it is audible.
I don't know, probably in smaller room it would be inaudible, I never tried.
I don't know, probably in smaller room it would be inaudible, I never tried.
Griesinger's quote:
"Reproduced sound in a small room lacks this living quality. Often low frequencies are not perceived as external, but inside the head. This is because the low frequencies lack any pressure gradient; the interaural time delay is zero, and remains zero when the head is rotated. Not knowing how to localize these sounds, we perceive them as internal."
It's odd, but I've never experienced this. In fact, after informally testing a fairly wide group of people, I can't remember a single person making a similar comment.
For me, those I've tested, and presumably Markus - the result isn't "in head" but rather indistinct and "in room".
Example (..one of the better DIY'ed designs presented/recorded on youtube):
DIY Speakers ( ScanSpeak+SBAcoustics+B&G) - YouTube
Everything except the bass guitar (and a lower freq. drum) has some localization feature (to me). The bass guitar (and lower freq. drum) however is just "plummy" and indistinct and is associated within the listening room, NOT my "head". Of course this is a recording of a stereo reproduction (..you can't "remove" the effects of the room perceptually, or at least I can't), and therefor it isn't quite the same as if you were in the room listening to it. Still, that's pretty much the same effect that I get with most NON-dipole/cardiod setups.
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I think it is rarely mentioned because people do not know to pay attention to it.
Griesinger may well be ahead of his own time
Maybe like after 20 years from now it will taken seriously..I think it is rarely mentioned because people do not know to pay attention to it.
Griesinger may well be ahead of his own time
Perhaps I should have had those same people put on headphones and asked for a description from each..
I on the other hand am very much aware of the "in the head" sound, and again - that is NOT the effect I get.
Griesinger is well ahead of his peers in several respects (..and he is right now taken very seriously), but I don't think he is necessarily correct with all of his statements.
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Scott,
Tell us again please why we should listen to that youtube clip ?
Because while listening to it I found out the deepest truth about youtube, the true meaning of it ! It sounds like coming from a tube, literally !
Are you telling you don't get in the head sound if you place a single mono bass speaker 0.5 m behind your head symmetrical to median plane at ear level located in the middle of the room ?
- Elias
Tell us again please why we should listen to that youtube clip ?
Because while listening to it I found out the deepest truth about youtube, the true meaning of it ! It sounds like coming from a tube, literally !
I on the other hand am very much aware of the "in the head" sound, and again - that is NOT the effect I get.
Are you telling you don't get in the head sound if you place a single mono bass speaker 0.5 m behind your head symmetrical to median plane at ear level located in the middle of the room ?
- Elias
I was posting to Elias' comment about how my room is laid out relative to the sub/woofer placement. I had assumed that a similar position was what you had suggested to Elias. He, Elias, then posted that you were not speaking of such a sub/woofer placement .. as in my rooms layout. In that post he also deduced that the main listening position was in the circle area.
I then posted that "Yes, .. " that was the listening position and that I must have misunderstood your prior suggestion to Elias about sub/woofer placement. (I don't think I did .. or maybe mine is a few inches too far back/forward/left/right/up/down/backward ... don't know
... regardless, I'm not about to debate that. I'll leave that to the scientists here.)Make sense now markus?
As far as the Greisinger comments go, I have trouble with the fact that a 100 Hz tone has a ten foot wavelength and we are supposed to somehow believe that a reasonable "gradient" can be achived between the ears? At 20 Hz the wavelength is 50 feet. Come on, the signal at the two ears at these frequencies has to be extremely similar if not identical. The correlation has to be nearly 1.0.
Dave: 6 dB addition of SPL is the exact same as a 3 dB addition to PWL. Multiple subs could be an issue if the structure is not very solid because there can be a lot of structure borne sound due to the heavy subs coupling to the structure. AT LFs sound issolation becomes a seriously complex problem of coupled modes and structure borne sound. In this regard a dipole would fair far worse since its mechanical forces generate far less SPL than a monopole, so structurally they would generate a lot more LF coupling. Maybe this is what makes them sound different!?
Dave: 6 dB addition of SPL is the exact same as a 3 dB addition to PWL. Multiple subs could be an issue if the structure is not very solid because there can be a lot of structure borne sound due to the heavy subs coupling to the structure. AT LFs sound issolation becomes a seriously complex problem of coupled modes and structure borne sound. In this regard a dipole would fair far worse since its mechanical forces generate far less SPL than a monopole, so structurally they would generate a lot more LF coupling. Maybe this is what makes them sound different!?
It comes down to whether or not we can create a pressure difference beetwen left and right eardrum. Even with mono signals sometimes freq dependant image shifts can occur depending on how imperfect the acoustic symmetry of the setup is. With phase (and mag) differences which can be coded in the source channels there should be enough chances that partly "artificial" localisation of deeper bass notes could be accomplished in small rooms, with some help from modal effects (nulls at ear locations, notably). Also IRCC, there is a recent peer-reviewed paper on the localisation of bass which showed that freq range might need an update to lower ranges than currently established... I just can't find it anymore.
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If the signal has modulations and they are reproduced accordingly, then we are more able
That's exactly the problem, you just can't do that within an acoustically small room. You can do it with headphones but why the heck are low frequencies still not externalized? Something is wrong in Griesinger's theory.
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