i simply grabbed the technical papers that i could, but you will see the same pros and cons in any reputable speaker design cookbook and they're frequently quoted by magazines such as stereophile and formerly audio magazine, especially back when infinity, boston acoustics were still acoustic suspension as well as the wedge shaped "giant killer" $500 speakers with vifa silk domes from back then or the multi-megabuck designs from wilson (watt puppies) or the infamous giant time aligned d'appoloto towers from the 90s that made their way into recording studios and that many considered the best in the world.
you bet i have an attitude as i get tired of arguing facts with those who go out of their way to dismiss them or change the subject. sure, kicker makes car speakers and those aren't generally as high end as the likes of seas, vifa, visiton & eton etc., but they still use the same science as any other reputable manufacturer.
i won't budge an inch from the truth no matter how many liars try to shout me down or change the subject.
if my 3 or 4 sources are all the stupid liars you claim they are, then show me a REPUTABLE website that says otherwise, or argue with someone else as i'm just not hearing your lies and never will.
ported speakers are more popular because most people like the big boom over the tight thump. that's a TRUTH. that's why so few companies besides NHT who still haven't sold out make acoustic suspension. when the BBC wanted THE MOST ACCURATE MONITORS, they didn't turn to ports, did they?
if you knew anything about recording monitors, the current model many consider to be the most accurate in the world, regardless of cost are barefoot micromain 27 monitors as reviewed here by "golden ears" sound on sound
Barefoot Sound MicroMain27
who, coincidently enough had this to say about ports
i have ZERO PATIENCE for arguing with anyone who denies the truth and who's an apologist. you can claim some sort of voodoo magic that cancels all of the RESONANCE in a ported speaker, but it's just that, wishful thinking, flat out ignorance, or a sad "cling to your lie at all costs" mindset more befitting of a religious zealot than anyone to be taken seriously.
"truth by popularity contest" is the mantra of idiots.
it's pretty pathetic to attack my sources (there everywhere, i don't play the "pick & chose game") without providing any of your own as you know you can't find them and would look stupid quoting any legit source. i stumbled across the barefoot quotes BY ACCIDENT not looking specifically for more ammo against distortion boxes, but just to name them as one of the most accurate monitors in the world. there's a REASON why the original acoustic research AR-1s are legendary, they were an huge leap in clarity over their ported competition.
as someone who's into percussion and that likes the tightest thump possible, i'm very annoyed by the boom artifacts of ported speakers and the first time i heard CLEAR bass was those infinity minimonitors despite hearing dozens of brands in shops. it had the SPEED & DETAIL that no larger, especially ported speaker lacked. the only bass that's better is the lightning fast snap from a planar. so what if it's rolled off, you can at least HEAR it clearly! needless to say, i never take the foam plugs out of my missions. they sound like a boom box when i do (although their 1/2" MDF cabinet is still lived sealed too)
i'd love to own a pair of barefoots myself, or even NHT classic threes, although the treble in those is a tiny bit metallic, but the midrange is super clear and the imaging blows my former superzeros away.
so where are YOUR FACTS? if you can't provide any legit sources, (and i KNOW YOU CAN'T) you're just posturing. instead of just quoting me and trying to dismiss me because you just don't like my efyou and your lies attitude, post some facts. nothing shuts me up faster than a credible source and your opinions aren't credible no matter how strongly you cling to them.
i skimmed that link in the post above, and didn't see any comparisons between designs... another "change the subject" obfuscation?
you bet i have an attitude as i get tired of arguing facts with those who go out of their way to dismiss them or change the subject. sure, kicker makes car speakers and those aren't generally as high end as the likes of seas, vifa, visiton & eton etc., but they still use the same science as any other reputable manufacturer.
i won't budge an inch from the truth no matter how many liars try to shout me down or change the subject.
if my 3 or 4 sources are all the stupid liars you claim they are, then show me a REPUTABLE website that says otherwise, or argue with someone else as i'm just not hearing your lies and never will.
ported speakers are more popular because most people like the big boom over the tight thump. that's a TRUTH. that's why so few companies besides NHT who still haven't sold out make acoustic suspension. when the BBC wanted THE MOST ACCURATE MONITORS, they didn't turn to ports, did they?
if you knew anything about recording monitors, the current model many consider to be the most accurate in the world, regardless of cost are barefoot micromain 27 monitors as reviewed here by "golden ears" sound on sound
Barefoot Sound MicroMain27
who, coincidently enough had this to say about ports
why not stop clinging to your lies and false illusions and simply accept the facts.
i have ZERO PATIENCE for arguing with anyone who denies the truth and who's an apologist. you can claim some sort of voodoo magic that cancels all of the RESONANCE in a ported speaker, but it's just that, wishful thinking, flat out ignorance, or a sad "cling to your lie at all costs" mindset more befitting of a religious zealot than anyone to be taken seriously.
"truth by popularity contest" is the mantra of idiots.
it's pretty pathetic to attack my sources (there everywhere, i don't play the "pick & chose game") without providing any of your own as you know you can't find them and would look stupid quoting any legit source. i stumbled across the barefoot quotes BY ACCIDENT not looking specifically for more ammo against distortion boxes, but just to name them as one of the most accurate monitors in the world. there's a REASON why the original acoustic research AR-1s are legendary, they were an huge leap in clarity over their ported competition.
as someone who's into percussion and that likes the tightest thump possible, i'm very annoyed by the boom artifacts of ported speakers and the first time i heard CLEAR bass was those infinity minimonitors despite hearing dozens of brands in shops. it had the SPEED & DETAIL that no larger, especially ported speaker lacked. the only bass that's better is the lightning fast snap from a planar. so what if it's rolled off, you can at least HEAR it clearly! needless to say, i never take the foam plugs out of my missions. they sound like a boom box when i do (although their 1/2" MDF cabinet is still lived sealed too)
i'd love to own a pair of barefoots myself, or even NHT classic threes, although the treble in those is a tiny bit metallic, but the midrange is super clear and the imaging blows my former superzeros away.
so where are YOUR FACTS? if you can't provide any legit sources, (and i KNOW YOU CAN'T) you're just posturing. instead of just quoting me and trying to dismiss me because you just don't like my efyou and your lies attitude, post some facts. nothing shuts me up faster than a credible source and your opinions aren't credible no matter how strongly you cling to them.
i skimmed that link in the post above, and didn't see any comparisons between designs... another "change the subject" obfuscation?
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Budget,
I posted links to some actual measurements, you should have a look at those. Distortion measurements are shown, in some cases the same driver in a sealed and vented version. See for yourself.
I posted links to some actual measurements, you should have a look at those. Distortion measurements are shown, in some cases the same driver in a sealed and vented version. See for yourself.
i reread it, and there's ZERO mention of subwoofer types, just info on how to measure a sub in your room and make it integrate with your system.
regardless, my ears KNOW when i'm hearing sloppy resonant bass, and when it's thumping. i can hear the tightness and clarity as can every recording engineer who uses NS-10s, every audiophile who made the switch to AR-1s in the 50s, and pretty much ANY credible audio magazine, even autosound which don't just do SPL drag races but that also have SQ competitions.
in using the keywords speaker types compared ported, these are the FIRST results that came up
from wikipedia (hey, i know it's not the best source, but i'm going through the results SYTEMATICALLY)
Sealed Vs Ported Subwoofer Boxes regarding ported speakers:
hif just talk about the difference between front & rear mounted ports with no comparisons to acoustic suspension
from Sealed vs. Ported Enclosures | Klaus Audio
then there's
(whose bread and butter is selling PA drivers destined for ports, slots & vents BTW. kudos to them for having the integrity to tell the truth about the compromises in their own products!!! i'd call that quote THE KO of the whole bunch myself)
Tech Tips: Advantages of front ported versus rear ported speakers. | Sweetwater.comok... they're just comparing front vs rear porting
the next two sources (polk audio FORUM & dummies.com both vote thumbs down for ports & distortion... STILL 100% unanimous!!!!) and i'm betting that slightly more credible crutchfield.com (who offer EXCELLENT how tos and comparisons of all sorts with product info that's generally better than manufacturer's own websites) will chime in on the truth too
Subwoofer Enclosures
i really hate playing the majority rules game, but every source i can find that compares acoustic suspension to ported at the very least claims that acoustic suspension is THE choice for sound quality. ported woofers offer sloppy, distorted but LOUD & DEEP bass. the only concession i'll make is that's the sound most people seem to prefer, but that doesn't stop it from smearing transients, clarity and decay through RESONANCE. they're called TUNED ports for a reason. resonance is simply adding harmonics to the original signal that were never there to begin with causing "one note bass" at the extremes, but never fully disappearing. if acoustic suspension didn't offer increased detail and speed (my ears hear it clearly... the smaller the woofer, the tighter) then no one would bother making them
source after source from manufacturers & audio rags to recording engineers all agree that acoustic suspension = best SQ in traditional speakers where ported designs just offer euphonic excitement at the expense of a TIGHT (read undistorted no matter how you try to mince words) sound.
go google the very keywords i used if you think i omitted any results that contradict what everyone but diehard port lovers with a personal agenda and an axe to grind against the "wimpy sound of sealed" they don't like. actually, that's a good analogy... ports are like big mouth loud liars and air springs are quiet truth speakers. yeah... i like that analogy a lot! ports just like to blow alot of hot air... LITERALLY (as their woofers strain harder & blow faster than acoustic suspension design whose impedence rises as frequencies drop generating thus less heat)
regardless, my ears KNOW when i'm hearing sloppy resonant bass, and when it's thumping. i can hear the tightness and clarity as can every recording engineer who uses NS-10s, every audiophile who made the switch to AR-1s in the 50s, and pretty much ANY credible audio magazine, even autosound which don't just do SPL drag races but that also have SQ competitions.
in using the keywords speaker types compared ported, these are the FIRST results that came up
from wikipedia (hey, i know it's not the best source, but i'm going through the results SYTEMATICALLY)
from Bass reflex - Wikipedia, the free encyclopedia
Sealed Vs Ported Subwoofer Boxes regarding ported speakers:
hif just talk about the difference between front & rear mounted ports with no comparisons to acoustic suspension
from Sealed vs. Ported Enclosures | Klaus Audio
notice he didn't say excellent, better or even equal and that should be taken in context with his previous statement
the next link was for some blog and a users review of some "tacoma taco system", the carstereo.com just does a comparison of types of ported boxes
then there's
from http://www.eminence.com/2011/06/sealed-vs-ported-enclosures/
(whose bread and butter is selling PA drivers destined for ports, slots & vents BTW. kudos to them for having the integrity to tell the truth about the compromises in their own products!!! i'd call that quote THE KO of the whole bunch myself)
in essence knocking the intended market for their own products!!! so far it's unanimous and i'm betting a nickel that sweetwater (who specialize in audio for pros) will confirm the truth that port lovers wish would just go away... ports BOOM by adding distortion (resonance) to the original signal to make it louder. we'll see if my prediction is right...
Tech Tips: Advantages of front ported versus rear ported speakers. | Sweetwater.comok... they're just comparing front vs rear porting
the next two sources (polk audio FORUM & dummies.com both vote thumbs down for ports & distortion... STILL 100% unanimous!!!!) and i'm betting that slightly more credible crutchfield.com (who offer EXCELLENT how tos and comparisons of all sorts with product info that's generally better than manufacturer's own websites) will chime in on the truth too
Subwoofer Enclosures
i see they diplomatically avoid saying anything negative about ported speakers as most are and unless they still carry NHT, probably none of their home speakers are acoustic suspension, but they DO name acoustic suspension as superior in SQ for a "minor win" for the truth.
i really hate playing the majority rules game, but every source i can find that compares acoustic suspension to ported at the very least claims that acoustic suspension is THE choice for sound quality. ported woofers offer sloppy, distorted but LOUD & DEEP bass. the only concession i'll make is that's the sound most people seem to prefer, but that doesn't stop it from smearing transients, clarity and decay through RESONANCE. they're called TUNED ports for a reason. resonance is simply adding harmonics to the original signal that were never there to begin with causing "one note bass" at the extremes, but never fully disappearing. if acoustic suspension didn't offer increased detail and speed (my ears hear it clearly... the smaller the woofer, the tighter) then no one would bother making them
source after source from manufacturers & audio rags to recording engineers all agree that acoustic suspension = best SQ in traditional speakers where ported designs just offer euphonic excitement at the expense of a TIGHT (read undistorted no matter how you try to mince words) sound.
go google the very keywords i used if you think i omitted any results that contradict what everyone but diehard port lovers with a personal agenda and an axe to grind against the "wimpy sound of sealed" they don't like. actually, that's a good analogy... ports are like big mouth loud liars and air springs are quiet truth speakers. yeah... i like that analogy a lot! ports just like to blow alot of hot air... LITERALLY (as their woofers strain harder & blow faster than acoustic suspension design whose impedence rises as frequencies drop generating thus less heat)
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budget, I am not sure if you are open to other inputs or have your mind made up but you might look further.
A few thoughts, you assert that the greater moving mass of the larger driver makes it slow. In reality the drivers “speed” or high frequency performance is set by the Rdc and series inductance not mass. Take a sealed box woofer, measure the frequency response, then, glue a ring of lead solder to the dustcap / cone joint and re-measure.
You will see that even doubling the moving mass, has NO real effect on the attack or high frequency behavior. It is the lower inductive corner associated with big motors on heavy drivers that can make them “slow”, not the mass.
So far as distortion, for a direct radiator like your contemplating, if you took a given driver and put it in a proper vented box and in a proper sealed box and then drive them to the same SPL, you would find that above the vented boxes low corner for say an octave above that, it will have less distortion because the radiator is moving less. The distortion a driver produces, is primarily a function of how far it’s moving / how linear the motor and suspension is. A vented box system has a minimum excursion at / around it’s low corner while the sealed system has a continually increasing excursion.
Your assertion about bad sounding is not a function of the approach but improper design. Speakers have a “high pass” corner, here, set by the boxes cutoff. The shape of that knee does have a strong effect on how a system sounds. Just like with any electrical filter, a knee with a LF peak has “a lot of bass” but does ring. The shape of this is called the filter Q and one finds a Q between .5 and .7 has optimum shape while Q’s greater than 1 are used to make a boom. Q’s less than say .6 sound “fast” when people listen to a kick drum.
This is faulty however as one is seeking a piece of the system not the compete reproducer. A kick drum is a wide spectrum signal heavy on the bass and when you play it through a subwoofer, your ears will pick the one that sounds most like a kick drum. What you want though is the one that most accurately reproduces the part of the signal coming out of your low pass filter and this will not sound like a kick drum as it assumes the rest of the system produces the upper components.
Unless your system will always be in your living room where you have room gain (the only thing in acoustics close to a free lunch) , you should strongly consider the (as much as) 6 dB advantage of the vented box.
Outdoors or in a large room there is no pressure reinforcement, notice essentially NO ONE uses simple sealed boxes for low frequency production in large scale sound.
Lastly, there is a great deal of “lore” in audio, often what seems logical is used as the explanation but like how moving mass has no effect on woofer “speed” with acoustics, one is dealing with an involved phenomena who’s principals are not always obvious.
Best,
Tom
A few thoughts, you assert that the greater moving mass of the larger driver makes it slow. In reality the drivers “speed” or high frequency performance is set by the Rdc and series inductance not mass. Take a sealed box woofer, measure the frequency response, then, glue a ring of lead solder to the dustcap / cone joint and re-measure.
You will see that even doubling the moving mass, has NO real effect on the attack or high frequency behavior. It is the lower inductive corner associated with big motors on heavy drivers that can make them “slow”, not the mass.
So far as distortion, for a direct radiator like your contemplating, if you took a given driver and put it in a proper vented box and in a proper sealed box and then drive them to the same SPL, you would find that above the vented boxes low corner for say an octave above that, it will have less distortion because the radiator is moving less. The distortion a driver produces, is primarily a function of how far it’s moving / how linear the motor and suspension is. A vented box system has a minimum excursion at / around it’s low corner while the sealed system has a continually increasing excursion.
Your assertion about bad sounding is not a function of the approach but improper design. Speakers have a “high pass” corner, here, set by the boxes cutoff. The shape of that knee does have a strong effect on how a system sounds. Just like with any electrical filter, a knee with a LF peak has “a lot of bass” but does ring. The shape of this is called the filter Q and one finds a Q between .5 and .7 has optimum shape while Q’s greater than 1 are used to make a boom. Q’s less than say .6 sound “fast” when people listen to a kick drum.
This is faulty however as one is seeking a piece of the system not the compete reproducer. A kick drum is a wide spectrum signal heavy on the bass and when you play it through a subwoofer, your ears will pick the one that sounds most like a kick drum. What you want though is the one that most accurately reproduces the part of the signal coming out of your low pass filter and this will not sound like a kick drum as it assumes the rest of the system produces the upper components.
Unless your system will always be in your living room where you have room gain (the only thing in acoustics close to a free lunch) , you should strongly consider the (as much as) 6 dB advantage of the vented box.
Outdoors or in a large room there is no pressure reinforcement, notice essentially NO ONE uses simple sealed boxes for low frequency production in large scale sound.
Lastly, there is a great deal of “lore” in audio, often what seems logical is used as the explanation but like how moving mass has no effect on woofer “speed” with acoustics, one is dealing with an involved phenomena who’s principals are not always obvious.
Best,
Tom
One of the best sounding PA-Systems on this planet is the STOLL Convertible in Line Array Mode accompanied by their new STOLL Infralow subs. You'll only find a press release online about the sub.
The four-way FIR-filtered active-driven system incorporates an (electronically adjustable) lowend down to 18 Hz/-6dB with full power bandwidth and an overall hi-pass characteristics of only 12dB/oct. with a Q of 0.5, using 18"s with a lin xmax of +-19mm, low and high mids are covered by waveguide loaded 5" units and the mid-highs are covered by an proprietary AMT with waveguide which covers more than 95% of the cabinet height.
A stereo system, driven with about 70 kW, with two six-element lines and four Infralows can deliver an 99 dBA Leq and 128 dB peak SPL in 30m distance.
The system is truly time- and phase-coherent over a wide frequency band, has very controlled dispersion and it has to be heard to be believed, how neutral and precise PA-Sound can be.
The lows are simply from another planet: You've never heard a system going down deep like this combining it with an ultra-fast transient attack, not to talk of the highly resolved mids due to small drivers and the highs miles ahead of any CD.
The whole system sounds like a FR.
This manufacturer of Switzerland is working for over 25 years now and known only to insiders, you can find them under: www.stoll-speakers.com
Of course, this is no DIY, and I doubt in being able to copy it, but looking at their hp gives some insight, and I think the filtering they do is quite important, something mostly not well understood and implemented in many systems, being it PA or Hifi.
The four-way FIR-filtered active-driven system incorporates an (electronically adjustable) lowend down to 18 Hz/-6dB with full power bandwidth and an overall hi-pass characteristics of only 12dB/oct. with a Q of 0.5, using 18"s with a lin xmax of +-19mm, low and high mids are covered by waveguide loaded 5" units and the mid-highs are covered by an proprietary AMT with waveguide which covers more than 95% of the cabinet height.
A stereo system, driven with about 70 kW, with two six-element lines and four Infralows can deliver an 99 dBA Leq and 128 dB peak SPL in 30m distance.
The system is truly time- and phase-coherent over a wide frequency band, has very controlled dispersion and it has to be heard to be believed, how neutral and precise PA-Sound can be.
The lows are simply from another planet: You've never heard a system going down deep like this combining it with an ultra-fast transient attack, not to talk of the highly resolved mids due to small drivers and the highs miles ahead of any CD.
The whole system sounds like a FR.
This manufacturer of Switzerland is working for over 25 years now and known only to insiders, you can find them under: www.stoll-speakers.com
Of course, this is no DIY, and I doubt in being able to copy it, but looking at their hp gives some insight, and I think the filtering they do is quite important, something mostly not well understood and implemented in many systems, being it PA or Hifi.
budget-minded.
much of what you say is true, but awfully polarised. It isnt quite as black and white as you assert it is.
Besides, im sure the BBC DID use ported systems, and for their most accurate, least compromised, highest spec'd studio monitors of the era.
much of what you say is true, but awfully polarised. It isnt quite as black and white as you assert it is.
Besides, im sure the BBC DID use ported systems, and for their most accurate, least compromised, highest spec'd studio monitors of the era.
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budget, the link to the article I wrote of course is about integration in a domestic room. However, regarding distortion, the link to the HT shack measurements show this aspect. They also show effects of port compression at high SPL and ringing behaviour.
not true at all. that's why some passive radiators came with weighting kits to lower their resonant frequencies by making them harder to push.
there's a question on some trivia game... which of these accelerates the fastest... a flea, a hummingbird, a cheetah or a space shuttle. the correct answer of course is the flea whose tiny mass allows it to accelerate to 2,000 some Gs which would destroy anything much larger
that's why super light planar speakers have speed that cone drivers can't match.
yes, magnet size, suspension compliance and all other factors play a part, but pretty much every speaker manufacturer tries to make their speakers as light as possible even using exotic materials like carbon fiber or aluminum honeycombs to achieve the lowest mass possible.
if you don't believe the principle (why you wouldn't eludes me) tell which you could shake faster, a piece of paper or a 8x4 piece of plywood.
then there's the issue of wavelengths (which aren't as critical in the bass range). you can't get good treble out of a driver bigger than a high frequency's wavelength. that's why full range speakers have whizzer cones.
i just can't stand the sound of slow sloppy bass no matter how much i can feel it in my gut. the faster & tighter it is, the better. the fastest, but a huge margin is planar. they have even fewer distortion artifacts than acoustic suspension because they snap so fast. i can hear the difference clearly on a well recorded kick drum.
it was the ABSENCE of resonances and speed in tiny infinitys that blew me away. i could hear all the clarity that was missing, particularly compared to fugly sounding club speakers. i had to do some reading up to find out the whys behind it, and still trust the same science now as do all of the sources i quoted that you're dismissing
back to a previous statement... it was the dunlavy sovereigns i was talking about that were considered the best in the world. all i could remember was they started with a D until this morning
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Don't care to join this argument but I would like to say that this is deliciously ironic, after having seen you try to prove a point by repeating popular opinion.
Budget: you are confusing a number of issues. Resonant freq and High Freq roll off being one of them.
Perhaps if you would take a step back and look at things. You are getting advice from some pros in the field. Tom Danley was nice enough to take the time and explain some speakers 101 stuff to you.
Rather than going into attack mode, simply put down your pre-conceptions and look at what he said. If it does not make sense, then think about it some more rather than going into attack mode.
He knows more than many of us ....
Perhaps if you would take a step back and look at things. You are getting advice from some pros in the field. Tom Danley was nice enough to take the time and explain some speakers 101 stuff to you.
Rather than going into attack mode, simply put down your pre-conceptions and look at what he said. If it does not make sense, then think about it some more rather than going into attack mode.
He knows more than many of us ....
On the topic of high end pro audio, no one is better qualified than Tom Danley. I'd think twice before telling him he's got it wrong.
Now let's look at a real measured example, same driver ...
Sealed
DIY TC Sounds TC-2000 15" sealed 90L - Home Theater Forum and Systems - HomeTheaterShack.com
Ported
DIY TC Sounds TC-2000 15" ported 270L - Home Theater Forum and Systems - HomeTheaterShack.com
Now the distortion ...
Sealed
Ported
The sealed version was not made to have the same response, that tips things more in favour of the vented. If we compare the distortion at 20 Hz at 102 db, the sealed has 24% THD while the vented has 5%. We need to look down low because this is a HT sub setup, the tuning is happening down there. This particular driver is a fairly extreme one designed for very high excursion. If we look at pro woofers designed for higher tuning and much lower excursion, we must remember they were designed with vented boxes in mind where the port will compensate for the declining linearity with excursion. In that case we would then be looking at what happens higher up.
If you scroll down on those measurements and look at the spectral decay, the ported has some ringing down near the port, that is expected. It occurs at low frequencies, but in the range where music happens, it's about the same in the ported version.
These measurements are typical of others I've seen for the reasons Tom described. Excursion and distortion go together.
Now there is one driver in there that goes go against the trend - TC Sounds LMS. You can see it sealed vs PR. It is the exception. I can only guess that the motor itself is now performing so well that the PR isn't really able to improve distortion, it simply increases extension and output. This certainly doesn't apply when using a lot of cheap small woofers.
Now let's look at a real measured example, same driver ...
Sealed
DIY TC Sounds TC-2000 15" sealed 90L - Home Theater Forum and Systems - HomeTheaterShack.com
Ported
DIY TC Sounds TC-2000 15" ported 270L - Home Theater Forum and Systems - HomeTheaterShack.com
Now the distortion ...
Sealed
An externally hosted image should be here but it was not working when we last tested it.
Ported
An externally hosted image should be here but it was not working when we last tested it.
The sealed version was not made to have the same response, that tips things more in favour of the vented. If we compare the distortion at 20 Hz at 102 db, the sealed has 24% THD while the vented has 5%. We need to look down low because this is a HT sub setup, the tuning is happening down there. This particular driver is a fairly extreme one designed for very high excursion. If we look at pro woofers designed for higher tuning and much lower excursion, we must remember they were designed with vented boxes in mind where the port will compensate for the declining linearity with excursion. In that case we would then be looking at what happens higher up.
If you scroll down on those measurements and look at the spectral decay, the ported has some ringing down near the port, that is expected. It occurs at low frequencies, but in the range where music happens, it's about the same in the ported version.
These measurements are typical of others I've seen for the reasons Tom described. Excursion and distortion go together.
Now there is one driver in there that goes go against the trend - TC Sounds LMS. You can see it sealed vs PR. It is the exception. I can only guess that the motor itself is now performing so well that the PR isn't really able to improve distortion, it simply increases extension and output. This certainly doesn't apply when using a lot of cheap small woofers.
popular opinion be darned... ported speakers sound like crap and acoustic suspension sounds quicker & freer from distortion. i can hear it even if you can't.
they slow the sound down by adding resonance. the delayed backwaves and resonance blur transients making "pum pum pum" sound more like "boooo boooo boooo" i just don't like that sound and never will. i like transients that smack hard more than resonate big. boom gives me a headache anyways.
BTW science is NOT about "popular opinion". resonance is a very real phenomenon whether you admit it or not, just not as extreme as blown bottle resonance in any "decent" ported speaker, but the same thing and i can hear it. the best thump to me is an 8" or smaller sealed woofer short of a lightning fast planar that has scary bass realism. that's my idea of a sub.
they slow the sound down by adding resonance. the delayed backwaves and resonance blur transients making "pum pum pum" sound more like "boooo boooo boooo" i just don't like that sound and never will. i like transients that smack hard more than resonate big. boom gives me a headache anyways.
BTW science is NOT about "popular opinion". resonance is a very real phenomenon whether you admit it or not, just not as extreme as blown bottle resonance in any "decent" ported speaker, but the same thing and i can hear it. the best thump to me is an 8" or smaller sealed woofer short of a lightning fast planar that has scary bass realism. that's my idea of a sub.
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😀😀😀
That's just my idea of a headphones sub.
4 ported 18" are my idea of an in-room sub system.😎
Budget minded, cheap high-Qts drivers in a ported box tuned too high made of thin chipboard is what gives that stereotypical "booommm-booommm" mud. High quality drivers in properly tuned (lower than "optimal" maximal flat tuning IME) high-quality cabinet can make your nose bleed with that midbass speed, yet go deep and give plenty of rumble, when needed.
On the other hand, you can make a sealed cab sounding "slow" by applying EQ to get a bump around 30...50 Hz; or by sloppy room acoustics giving the same bump.
On the gripping hand, it comes down to personal preferences - I generally prefer big, low-tuned ported boxes with proper room correction (though at the moment a friend lent me a sealed 12" sub for testing, and I rather like it, gives plenty of rumble below 40 Hz, shakes the sofa at 22 Hz; and yes, can sound "slow" and "muddy" when turned up too high relative to the mains), others may and will disagree.
On the other hand, you can make a sealed cab sounding "slow" by applying EQ to get a bump around 30...50 Hz; or by sloppy room acoustics giving the same bump.
On the gripping hand, it comes down to personal preferences - I generally prefer big, low-tuned ported boxes with proper room correction (though at the moment a friend lent me a sealed 12" sub for testing, and I rather like it, gives plenty of rumble below 40 Hz, shakes the sofa at 22 Hz; and yes, can sound "slow" and "muddy" when turned up too high relative to the mains), others may and will disagree.
😀
Chaps, you all seem to be getting a bit het-up about this. Fact is, all PA, (and domestic), systems are designed to a price point. Designers will use the best technology suitable for that price point to meet the goals of the marketing department. That's why we get different designs, though not usually sealed, as they are too big to easily fit in a truck.
Not sure why you want to stay away from horns. Bullet tweeters are horns, BTW.
Anyway, the system that stands out in my mind consists of:
B&C 18PS100 woofer (7 liter net volume tuned to 32Hz):
B&C SPEAKERS
B&C DCX50 compression driver (mid and tweet):
B&C SPEAKERS
JBL 2380A flat front biradial 90x40 horn:
http://www.parts-express.com/pdf/294-424s.pdf
Active crossover @ 500Hz and 9kHz. (three amps per channel required)
Cost of drivers and horn is about: $250+$700+$340...
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