If one gives me 24 pcs suitable 8" - I will test and tell you about the results
Magnepan has been showcasing a multi small driver dipole subwoofer tower along with their LRS plus panels and the listener evaluations have been overwhelmingly positive. There are no details on the design as of yet and Magnepan has not made it clear when they would be retailing the product. By appearance under the hiding ‘sock’ cover appear to be a tight dipole group of eight 6-7” woofers of some sort. DSP is employed .
Yeah small drivers can be arrayed, distributed around, or do some dual opposing setup to reduce vibration. Downside is multiplied cost.
Quick thought experiment on dynamics. Lets take a 6" driver and compare it to eight drivers, or roughly a 15". 8 drivers would be doubling cone area three times so with same low frequency extension (and excursion) we just gained 9db to max output capability, or dynamic headroom.
Some might think using a big driver or a lot of small ones is going overboard (home hifi) but it really isn't that big of a number. Same 9db headroom could be gained with single driver by cutting all the lownend out, almost two octaves (octave requires quadrupling cone area for same excursion). Want punchy kick bass on small loudspeaker? just add highpass filter to 100Hz to get headroom for it
Suddenly 9db is quite a big number as low frequencies are ruthless, wavelength gets very big and volume displacement to maintain SPL skyrockets, small speakers with small woofers just don't cut it the same.
edit. to keep room in the discussion I have to EQ cut my mains >10db around 60Hz and have about 10db dip around 30Hz so no matter the drivers are big or box alignment is this or that the frequency response is poo. It would be better to distribute the cone area around the room or try reduce effect of room by any means. Room can easily affect the frequency response worth eight times your system woofers, crazy stuff. It doesn't matter my speakers have been tuned to ~35Hz, or 45Hz, there is still about no 30Hz at listening position. The steady state frequency response would probably be nice without EQ if system started to roll of above the 60Hz peak. Here is why I suspect open baffle speakers and closed boxes sound better than reflex boxes, suits better the room and positioning and situation without EQ.
Quick thought experiment on dynamics. Lets take a 6" driver and compare it to eight drivers, or roughly a 15". 8 drivers would be doubling cone area three times so with same low frequency extension (and excursion) we just gained 9db to max output capability, or dynamic headroom.
Some might think using a big driver or a lot of small ones is going overboard (home hifi) but it really isn't that big of a number. Same 9db headroom could be gained with single driver by cutting all the lownend out, almost two octaves (octave requires quadrupling cone area for same excursion). Want punchy kick bass on small loudspeaker? just add highpass filter to 100Hz to get headroom for it
Suddenly 9db is quite a big number as low frequencies are ruthless, wavelength gets very big and volume displacement to maintain SPL skyrockets, small speakers with small woofers just don't cut it the same.edit. to keep room in the discussion I have to EQ cut my mains >10db around 60Hz and have about 10db dip around 30Hz so no matter the drivers are big or box alignment is this or that the frequency response is poo. It would be better to distribute the cone area around the room or try reduce effect of room by any means. Room can easily affect the frequency response worth eight times your system woofers, crazy stuff. It doesn't matter my speakers have been tuned to ~35Hz, or 45Hz, there is still about no 30Hz at listening position. The steady state frequency response would probably be nice without EQ if system started to roll of above the 60Hz peak. Here is why I suspect open baffle speakers and closed boxes sound better than reflex boxes, suits better the room and positioning and situation without EQ.
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edit time over, few more words why I'm writing on this thread. While I haven't been to any hifi shows (or heard many hifi systems in general) I would speculate that when one has good bass experience on a hifi show (or at friends place) it has three things to it: first its big enough system so that the dynamics was impactful, made an impact to you, more so than other systems you've recently heard. Second, it probably was positioned in the room better than some other systems, and you were listening at good spot. Third, the system was balanced well for the whole bandwidth, it had nice highs, nice mids, nice lows, it had nice problem free sound to it.
That said all I want from my home playback system is very good sound at practical listening position, I'm not interested about what makes it as long as it does might be different than what others have, or need, currently exploring what I need from my system and write what I think I've figured out so far so take it as is: use separate system for bass as they seem to have different requirements for positioning than mains, also have enough cone area and concentrate how to mate it all with the room. Not sure why I'm even writing all this Answer to opening posts is that I haven't heard best bass yet, I think, but have some experience and imagination to keep on searching for it. Alright, I'm out
That said all I want from my home playback system is very good sound at practical listening position, I'm not interested about what makes it as long as it does
might be different than what others have, or need, currently exploring what I need from my system and write what I think I've figured out so far so take it as is: use separate system for bass as they seem to have different requirements for positioning than mains, also have enough cone area and concentrate how to mate it all with the room. Not sure why I'm even writing all this Answer to opening posts is that I haven't heard best bass yet, I think, but have some experience and imagination to keep on searching for it. Alright, I'm out
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Yes, neighbours certainly agree. I did a (purely subjective) test some time ago between my dipole loudspeakers and a reflex boxed loudspeaker and listened to what I heard just outside the door. The dipole loudspeaker could play substantially louder (as in bloody loud) before it became anything near neighbour annoying outside the room. I did not measure anything but subjectively it was at least 10-12dB difference.
Sure….as mentioned before and in your case, 4 small sealed subs would easily mitigate your 10db pit of despair and likely be cheaper and easier to implement than bass traps. They offer portability and sustainability….you can take them with you. The compliance of the sealed enclosure is always going to produce more definition than the resonant enclosure…..just ask the hundreds of mix and mastering engineers who finalize their sessions with NS10’s. 4 boxes won’t need DSP, just some minor EQ to flatten the response….and maybe you wouldn’t need that with the right Hp and Lp settings.Yeah small drivers can be arrayed, distributed around, or do some dual opposing setup to reduce vibration. Downside is multiplied cost.
Quick thought experiment on dynamics. Lets take a 6" driver and compare it to eight drivers, or roughly a 15". 8 drivers would be doubling cone area three times so with same low frequency extension (and excursion) we just gained 9db to max output capability, or dynamic headroom.
Some might think using a big driver or a lot of small ones is going overboard (home hifi) but it really isn't that big of a number. Same 9db headroom could be gained with single driver by cutting all the lownend out, almost two octaves (octave requires quadrupling cone area for same excursion). Want punchy kick bass on small loudspeaker? just add highpass filter to 100Hz to get headroom for it
edit. to keep room in the discussion I have to EQ cut my mains >10db around 60Hz and have about 10db dip around 30Hz so no matter the drivers are big or box alignment is this or that the frequency response is poo. It would be better to distribute the cone area around the room or try reduce effect of room by any means. Room can easily affect the frequency response worth eight times your system woofers, crazy stuff. It doesn't matter my speakers have been tuned to ~35Hz, or 45Hz, there is still about no 30Hz at listening position. The steady state frequency response would probably be nice without EQ if system started to roll of above the 60Hz peak. Here is why I suspect open baffle speakers and closed boxes sound better than reflex boxes, suits better the room and positioning and situation without EQ.
As to the 1 large vs multiple small driver argument, on could and Wendell at Magnepan does believe that the difference and advantage for the smaller drivers is the combined motor strength offers greater control over the impulse response whether the system be sealed,OB or resonant. And he would be right on all accounts BUT when considering the application and such long wavelengths, can we actually hear the benefit? We can all agree that in the 60-180hz range, absolutely…..the smaller cones working with their motors in combination with near zero excursion the articulation improvement is audible…. it to get down low and excursion increases to mechanical inefficiencies of the smaller surface area, well…..all bets are off now.……if you don’t have enough of those small drivers power compression will set in and you’ll be back to square one…..so the question is when is enough is enough? Lol
Don't forget nearfield for the apartment, bonus points if it's an OB. Nearfield subwoofers, be they sealed or OB are very good at taking the room out of the equation for some very good quality bass that doesn't annoy the neighbours.
Mayhem13, Plenty is enough!
Example from graphs here https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/
If we take 1 acoustic Watt as target at 30Hz, thats about 112dB, requires ~1200cm3 volume displacement for closed box woofer(s).
Faital pro 18fh500 has Sd of 1207mm2 and enough xmax to make 1200cm3 of volume displacement, so with enough power it can do it. Its got xmax around 9mm so 18mm p-p travel, which would make ~2100cm3 volume displacement, goes pretty loud. I could say then that single 18" driver met my target nicely. Also any 15" driver whose Sd is around 850cm2 can reach the target if its xmax rating in datasheet is >7mm.
Popular 10" L26ROY can do 28mm p-p excursion and its cone area is 363cm2 which would make ~1016cm3 volume displacement and would not meet the target. Two of them would easily. As comparison Satori WO24P a 9.5" woofer has max p-p 17mm and Sd of 255cm2 so it would take three of them to reach 1200cm3 volume displacement target.
Then for example state of the art 6.5" Purifi woofer seems to be able to reach 9.8mm xmax but its cone area is only 133cm2 which makes ~260cm3 volume displacement per driver and would take five of these drivers to reach 1200cm3 volume displacement target.
This doesn't tell whats enough and what is not, probably less is already fine. Above is to illustrate what it takes in relative terms.
Example from graphs here https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/
If we take 1 acoustic Watt as target at 30Hz, thats about 112dB, requires ~1200cm3 volume displacement for closed box woofer(s).
Faital pro 18fh500 has Sd of 1207mm2 and enough xmax to make 1200cm3 of volume displacement, so with enough power it can do it. Its got xmax around 9mm so 18mm p-p travel, which would make ~2100cm3 volume displacement, goes pretty loud. I could say then that single 18" driver met my target nicely. Also any 15" driver whose Sd is around 850cm2 can reach the target if its xmax rating in datasheet is >7mm.
Popular 10" L26ROY can do 28mm p-p excursion and its cone area is 363cm2 which would make ~1016cm3 volume displacement and would not meet the target. Two of them would easily. As comparison Satori WO24P a 9.5" woofer has max p-p 17mm and Sd of 255cm2 so it would take three of them to reach 1200cm3 volume displacement target.
Then for example state of the art 6.5" Purifi woofer seems to be able to reach 9.8mm xmax but its cone area is only 133cm2 which makes ~260cm3 volume displacement per driver and would take five of these drivers to reach 1200cm3 volume displacement target.
This doesn't tell whats enough and what is not, probably less is already fine. Above is to illustrate what it takes in relative terms.
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From what I've read I believe those Magnepan subwoofer towers are running full range.
On large vs small woofer ... I think it has to do with the surface area that's coupling with the air. A larger woofer couples better with the surrounding atmosphere .. excites more air molecules than it's smaller counter part(s). Even multiple smaller drivers won't excite the air in the same way as a larger driver does locally.
Errror, volume displacement in the charts I looked at is calculated with Sd * xmax, where xmax is one way https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/post-55873 and I used p-p. So, even the 18fh500 would not meet the target within xmax in singles. Relationships stay the same so no need to panic, just think above is for pair of speakersMayhem13, Plenty is enough!
Example from graphs here https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/
If we take 1 acoustic Watt as target at 30Hz, thats about 112dB, requires ~1200cm3 volume displacement for closed box woofer(s).
Faital pro 18fh500 has Sd of 1207mm2 and enough xmax to make 1200cm3 of volume displacement, so with enough power it can do it. Its got xmax around 9mm so 18mm p-p travel, which would make ~2100cm3 volume displacement, goes pretty loud. I could say then that single 18" driver met my target nicely. Also any 15" driver whose Sd is around 850cm2 can reach the target if its xmax rating in datasheet is >7mm.
Popular 10" L26ROY can do 28mm p-p excursion and its cone area is 363cm2 which would make ~1016cm3 volume displacement and would not meet the target. Two of them would easily. As comparison Satori WO24P a 9.5" woofer has max p-p 17mm and Sd of 255cm2 so it would take three of them to reach 1200cm3 volume displacement target.
Then for example state of the art 6.5" Purifi woofer seems to be able to reach 9.8mm xmax but its cone area is only 133cm2 which makes ~260cm3 volume displacement per driver and would take five of these drivers to reach 1200cm3 volume displacement target.
This doesn't tell whats enough and what is not, probably less is already fine. Above is to illustrate what it takes in relative terms.
For one acoustic Watt output at 30Hz, 112dB, we would need a system that has volume displacement of 1200cm3
2x 18" driver with xmax >5mm
2x 15" driver with xmax >7mm
2x 12" driver with xmax >12mm
4x L26ROY
6x WO24P
10x ptt6-5x04-naa-08
You need 2.2 of the 18FH500 at full Xmax to produce 112dB at 1m:
This is before baffle step so you need to double that again (6dB) to maintain your SPL target. Then if you listen at 3m you’ll lose another 10dB, so you need to target 128dB at 1m, per side. But if you’re happy with 128dB peak in stereo (assuming low bass is mono), you can aim for 125dB per side (summing of incoherent acoustic sources). So you need…. a lot of drivers… 10 x 18FH500 per side… I like it 😂
Purifi need not apply
This is before baffle step so you need to double that again (6dB) to maintain your SPL target. Then if you listen at 3m you’ll lose another 10dB, so you need to target 128dB at 1m, per side. But if you’re happy with 128dB peak in stereo (assuming low bass is mono), you can aim for 125dB per side (summing of incoherent acoustic sources). So you need…. a lot of drivers… 10 x 18FH500 per side… I like it 😂
Purifi need not apply
Don't forget the gain you get from being in a listening environment that is more constrained than half space. In a real room at low frequencies you won't lose 10dB from the 3M listening distance either.
In reality a pair of 18"s will do a pretty good job with music in a domestic environment. I ran a pair of 18LW1400 at home for a few years and was completely happy with their output. They could effortlessly move stuff around the house. 🤔
250L tuned to 22Hz. One box per side.
In reality a pair of 18"s will do a pretty good job with music in a domestic environment. I ran a pair of 18LW1400 at home for a few years and was completely happy with their output. They could effortlessly move stuff around the house. 🤔
250L tuned to 22Hz. One box per side.
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Exactly - the acoustic impedance match with the surrounding air is more favourable as cone area increases, and the lower cone displacement seems to me to be a big factor in good bass reproduction.
I have no data to support my own hypothesis that a large area moving a little is better than a small area moving a lot, to put it in scientific terms, however in my experience I do feel that larger drivers have definite advantages in reproducing clean bass, along with excess amplifier output voltage capability for any given application. Multiple smaller drivers seem to be a viable option, but only if excursion is kept to sensible limits. I shudder inwardly on principle when I see any driver with an Xmax of 20mm!
Formulae to calculate particle velocity, acoustic pressure, volume velocity and acoustic impedance here https://www.prosoundweb.com/scientific-essence-of-sound-understanding-sound-propagation/3/
Never went further from this imagine how it plays out and what could make a difference between small and big woofer making same sound pressure. As far as I've understood ear senses acoustic pressure and for same acoustic pressure from two different sized woofers there is difference in volume velocity. Ear should not care where the sound pressure is originating from but the velocity component might affect other senses like feel?
Main difference of big and small cone is efficiency, lower acoustic impedance of bigger cone gets louder with same input power if I'm thinkin it straight. From here we get back to the headroom, small woofers just don't get as loud, perhaps not loud enough which makes impression bigger is better.
Visual system definitely tells the bigger system must sound better, especially if its shiny
Never went further from this imagine how it plays out and what could make a difference between small and big woofer making same sound pressure. As far as I've understood ear senses acoustic pressure and for same acoustic pressure from two different sized woofers there is difference in volume velocity. Ear should not care where the sound pressure is originating from but the velocity component might affect other senses like feel?
Main difference of big and small cone is efficiency, lower acoustic impedance of bigger cone gets louder with same input power if I'm thinkin it straight. From here we get back to the headroom, small woofers just don't get as loud, perhaps not loud enough which makes impression bigger is better.
Visual system definitely tells the bigger system must sound better, especially if its shiny
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Few more quick thoughts, big or small woofer means probably very different loudspeaker systems in many ways, boxes are different sized which affects for example directivity. Crossovers are at different points which could also affect directivity but also group delay and step response if it matters. Could be many things that make bigger woofers appear better sounding. I think we cannot evaluate good bass in isolation from rest of the system, how much perfect ideal godly bass would matter if the mids and highs are so nasty you wanna turn the system off? Also, as mentioned big speakers look impressive to eye, which probably also affects, also higher price point might be of importance. Big system doesn't have to be expensive either, one can buy multiple cheap big drivers with same cost than expensive small driver so cost is mainly in the enclosure /structure.
My bet is there is no magic behind the better sound and its mostly just having enough headroom and complete system design and implementation. More cone area means more capability to sound dynamic even with bit louder listening level, have more impact and some physical sensation. It doesn't mean all big systems sound good or that small systems sound bad, its just that the capability to sound better is there and if utilized well then yeah better perceived sound quality. If a small system worked better with a room at hand than some big system in the same room it could win easily in that particular case.
Takeaway is that when enought things snap together so that resulting system is problem free it wins a comparison to system that has problem(s). Of course some problems arise at some point while turning the volume pot toward infinity so bigger more efficient system wins. Its enough to have system capability beyond painful because there is no point listen any louder. I think 15" base get loud enough for me, no urge to get bigger, only fix the problems room lays on.
My bet is there is no magic behind the better sound and its mostly just having enough headroom and complete system design and implementation. More cone area means more capability to sound dynamic even with bit louder listening level, have more impact and some physical sensation. It doesn't mean all big systems sound good or that small systems sound bad, its just that the capability to sound better is there and if utilized well then yeah better perceived sound quality. If a small system worked better with a room at hand than some big system in the same room it could win easily in that particular case.
Takeaway is that when enought things snap together so that resulting system is problem free it wins a comparison to system that has problem(s). Of course some problems arise at some point while turning the volume pot toward infinity so bigger more efficient system wins. Its enough to have system capability beyond painful because there is no point listen any louder. I think 15" base get loud enough for me, no urge to get bigger, only fix the problems room lays on.
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