Actually it depends on room, and driver+baffle. I also wonder if we are talking about the direct field.... there is a point where I lean towards the speaker it appears that direct energy all of a sudden takes the lead and bass becomes much more full, in terms of FR quality and spl jumps up, so thus efficiency. Now that my baffle space is less, that transition point moved a little closer to the speaker but not by much and it happens at about 30"-25".... after you are within this part of the sound field, getting closer does not change things much... I am thinking this is the direct field
I feel like I designed my system the best I could to extend this direct field out as far as possible, from the loudspeaker by using the largest driver/horn/baffle I found feasible.
Mark a point 12" from your loudspeaker and one that is 100" away. Then measure the reflective path from a wall and back to 12" point, and same for the 100"
The further the listening distance, the less difference of reflective path length. Up close, the path length of wall reflections have a higher difference to the direct path....
Theres is nothing else here to ponder, unless my math is off 🤞 lol it is the reason why I've built a very large 2way that is omnidirectional at Xo point, so I can it as close as I want to the tweeter without loosing the woofer.
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I'd add; because of the long cycle time of bass. Reflective energy will always be a strong part of equation, in small. Its just that the proximity can be used to mitigate the room. Proximity won't literally drown out the room as in, make it a non factor. I also need to check the math on my statement above about path of businesses 🧐 and, the distance that I spoke of seems to be closer 20"
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This is at that point where you identify the source (subwoofer) itself - which you do NOT want to do.
One of the major problems here is it's utterly monophonic - you aren't hearing any difference from the right ear vs the left ear (even if the sound reproduced is actually mono).
There also isn't any real gradient when you are so close and have no diffraction-loss que from the subwoofer (and enclosure).
It's easier to get *closer to a dipole sub, especially if there isn't any real baffle to speak of and particularly if you get the null in the right spot relative to left vs. right ear.
*like really close, though you still don't want to have your head "inside" the cone area. Smaller diameter drivers make it easier to hear the pressure-loss as the sound wraps to the rear of the driver (for that near-ear).
Note the difference in resulting soundstage between open-back and closed-back headphones. Open-back (dipole) headphones often have less (even very little depending on the size of the driver next to your ears: *smaller driver size is better) of that "in-head" sound (at least at lower freq.s). Whereas Close-back (sealed monopoles) headphones often epitomize that "in-head" sound.
The dipole headphones on my Reverb G2 (and also on the Valve Index) are rather good from about the upper-bass - down. Anything above that is generally clear-sounding, but starts getting more "in-head".
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What a lovely setup!
This is my experience too, but I didn't push it at this level, yet
.I will restart experiments as soon as I’m done with the mains.
Well they were more big midbass than subs, just playing free without subs.
So on my last setup, very similar to current one, I had 4 woofers in nude clamshell/pushpull, laying on the floor.
They were bolt together so very easy to move around, and it would get better and better closer to me.
Also their orientation had an impact, with room and furniture interactions.
The good thing is that it brought back some of the chest thump that dipole are lacking.
And I enjoyed the look of it, so exotic.
But it was of course harder and harder to integrate with mains since playing up to maybe 150/200Hz, and just not practical with people around.
So I ended up with closed subs.
Another best bass I had, was in my car (before all home stuff).
First, simply IB sub, cleanest notes I’ve heard to this day. The small cabin had such effect on bass, you are literally inside the speaker there.
And then second best, but with more physical effect: 2x15'' in closed box right behind the driver seat, almost at ear level, less than 1 ft.
Don’t think about the typical one bass note ****, no they were clean, with big midbass horns deep below the dash, so very dynamic.
Man they had such a great chest thump! They would literally move air inside my lungs, to the point of disturbing my breathing.
And not at so crazy levels, my ears are fine.
At the end I left them play up to 150hz because it would get better and better (at the cost of some minor soundstage loss).
I’d like to repeat this at home one day...
Yes. But at which level? That's a typical example where overtones are stronger as the fundamental at 16Hz.A huge 16 ft stopped pipe organ goes down to around 16 Hz
So it's always good to be able to hear the whole spectrum of sound but you don't need full max power down there for music.
I know nearfield from measurements - at 30cm room influences start, in 1m you have full influence from the room. This is with "normal" sized speakers and woofers (25-35cm wide) and a small room. With "real" subwoofers (15-18") and way larger baffles this could extend a little and a BIG room will probably behave better. But it would be easy to test - just put a mic there.
Directivity plays a huge factor in this, thus driver/waveguide/baffle size, all play a part.
This is no proximity you can have that bass will not have influence by the room
Why would there be "full" room influence at 1m...whats at 2m? Super...full, influence?
Yes i must try to make some serious measurements, on my "things" in the basement sometime, from my old Infinity MTS Prelude i have R.A.B.O.S cd with tones from 18 hz and up i think.
But everything is so heavy and my back is total broken also with 7 herniated discs , and titanium screws and metal plate in the neck on 3 levels
First prototype speaker with 2 x XXLS 12 inch woofer, MTM with 2 x Audax HM130Z0 and audax tweeter in waveguide was 175 kilo each (in 3 colums), secund prototype with 3 x XXLS 12 inch woofer , 2 x Audax HM210Z10 and Mundorf AMT was about 215 kilo each (in 4 colums)
My 4 x Faital Pro XL18 is about 65 kilo each.
With such heavy speakers, everything becomes complicated when you want to move around and take measurements
So there is definitely a disadvantage with large speakers.
Attachments
The topic reflects where I am at with my system, as in, I am contemplating this currently.
What I am trying to expose is, whats most effective. I am in the way of thinking that multi sub seems to be very effective in a general sense, to where no matter the approach, adding multi sub to it, is desirable...
For example, take the current discussion of close proximity sub sources and add multi sub to the equation, I will predict that sound quality goes up.
Whats really on my mind is directivity. Where its easily had, we never, don't want it. Or at least I don't ever, not want it 🧐 and then when you learn what physics ask of waveguide, you understand why large basswave guides are rarely seen. In the most practical sense to me you might as well just corner load the speaker.
I think cardioid is the standard for bass "waveguide". Its the most practical given technology today. The direct field and nearfield are both are extended forward by directivity. It achieves the same effect as sitting close but stronger, and if you use cardioid and sit close this should work even better than before.
What I am trying to expose is, whats most effective. I am in the way of thinking that multi sub seems to be very effective in a general sense, to where no matter the approach, adding multi sub to it, is desirable...
For example, take the current discussion of close proximity sub sources and add multi sub to the equation, I will predict that sound quality goes up.
Whats really on my mind is directivity. Where its easily had, we never, don't want it. Or at least I don't ever, not want it 🧐 and then when you learn what physics ask of waveguide, you understand why large basswave guides are rarely seen. In the most practical sense to me you might as well just corner load the speaker.
I think cardioid is the standard for bass "waveguide". Its the most practical given technology today. The direct field and nearfield are both are extended forward by directivity. It achieves the same effect as sitting close but stronger, and if you use cardioid and sit close this should work even better than before.
Here's a thought.
Based on my last experiment and has perhaps a lot to do with room size.
Integration between driver and port.
My last woofer box was 1800 tall; 600 litres and a shelf port with a large distance between driver centre and the port exit. It sounds much better when you are 4 metres away from it.
My own observation is that if you have large enough driver area and power bass sounds better in a larger room such as a small country church.
Based on my last experiment and has perhaps a lot to do with room size.
Integration between driver and port.
My last woofer box was 1800 tall; 600 litres and a shelf port with a large distance between driver centre and the port exit. It sounds much better when you are 4 metres away from it.
My own observation is that if you have large enough driver area and power bass sounds better in a larger room such as a small country church.
For me the topic "best bass ever heard" is all about stereolistening, ( so to speak ) a pair of speaker with "best bass ever heard".
Getting great heavy bass with separate subwoofers is much easier, but for me thats homecinema/Movie and not 2 channel
Probably listened to 80 different systems that have the front speakers from 60-70-80 hz & use separate subwoofers, but never heard such a system where the bass integrates well enough for Hi-end stereosound/2 channel sound. ( even if the bass was real good and heavy)
And build these "front speakers" with "best bass ever heard" has been my goal, but it's really really hard to do.
Suggestion:
Go back and read Griesinger's article enough times so that you reasonably understand it (..which isn't easy).
http://www.davidgriesinger.com/asa05.pdf
Then think about it in the context of a dipole (and that one pole is in-phase and the other out-of-phase and the interaction with room relative to the listener).
Next, think about all of the above in relation to source-to-listener distance (and again, interaction with the room relative to the listener).
Finally, consider the addition of bass actuators for greater tactile sensation.
..which all leads to the very first post I made in this thread, and that post's very first sentence:
https://www.diyaudio.com/community/...ossibly-affordable.392381/page-2#post-7179247
I can dig the dipole, but am not currently a fan if actuators.
So first...dipole vs cardioid. Are you putting dipole over cardioid? Or could it be that it is just as good but even simpler to implement? I think in this case we are talking about dipole being used a certain way, that is, up close? In this situation, its competable with cardioid?
If thats the case, when I remove my rear panel, the enclosure becomes a ripole.
This is from the Griesinger paper;
"Consider the first of the rooms described above. The sound is very good. But the side walls are hard enough that the lateral modes propagate well from the front of the room to the listening position. If we add low frequency absorption to the side walls an interesting thing happens. Let’s assume there are two loudspeakers in the front of the room. We can measure the sound pressure in the lateral modes as a function of the distance from the loudspeakers, and we find the pressure drops off pretty quickly as we move back in the room. By the time we get to the listening position the lateral modes might be 6dB less than they were closer to the speakers. At the listening position the bass will be dominated by the medial modes, and the spatial impression will be poor. Placing a subwoofer pair closer to the listening position will solve the problem. In general, we want to put the subwoofers on either side of the listeners! If the back wall is closer to the listening position, put the subwoofers on the back wall. This will maximize both the bass uniformity and the spatial impression."
Thanks for that link!
@jawen - separate subwoofers is the best way in my opinion, but as you point out - they are rarely well integrated. I guess most people don’t use measurements to do this, and then you are bound to fail.
It’s a problem that can’t be solved properly without DSP, and audiophiles are scared ******** by it.
It’s a problem that can’t be solved properly without DSP, and audiophiles are scared ******** by it.
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Well I took the rear panel off my ppsl to convert it to ripole.
Nothing like what I expected... lost several modes in 50-80 range... Dipole seems to be effective in my situation... the FR is not as smooth... likely a trait of 6th order pass? Im not familiar with open baffle so....
2 18"s in ripole don't seem to be lacking dynamic capability, this situation is an area I avoided because whyyy would anyone want open baffle for a studio monitor... maybe dipole bass is where its at? Bass sensitivity increased? Don't get it...
It sounds pretty darn good with the more full spectrum presentation, yet it needs to be voiced now, since fr changed.... not to mention sensitivity is higher now so louder sounds better by trait...
Nothing like what I expected... lost several modes in 50-80 range... Dipole seems to be effective in my situation... the FR is not as smooth... likely a trait of 6th order pass? Im not familiar with open baffle so....
2 18"s in ripole don't seem to be lacking dynamic capability, this situation is an area I avoided because whyyy would anyone want open baffle for a studio monitor... maybe dipole bass is where its at? Bass sensitivity increased? Don't get it...
It sounds pretty darn good with the more full spectrum presentation, yet it needs to be voiced now, since fr changed.... not to mention sensitivity is higher now so louder sounds better by trait...
You can make multi-subs work without DSP. As to your second comment I suspect the idea of multiple displaced subs and the perceived complexity (it isn't that bad) has an effect.