best thump per buck/watt sub for a SEALED outdoor system?

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bass thump

Banned
2016-04-19 12:43 pm
i'm looking to build a bicycle trailer system that will eventually feature 4 x 12 inch subs in a pair of 1.23 cubic feet per woofer sealed car boxes (the biggest boxes that can fit the trailer i'm looking to get) and ORIGINALLY planned on getting cheap $10 high efficiency woofers rated down to 38Hz from MCM electronics, but looking at high efficiency woofers, they actually roll off lower than low efficiency home woofers in the bottom octave. that, and they're optimized for larger cabinet ported boxes. seeing that regular efficiency 12 inch woofers are generally rated around 80dB at 20Hz free air where higher efficiency ones only put out around 70Hz or less at 20Hz, standard subwoofers seems like the route to go.

i'm vaguely familiar with thiele small parameters eg. a system Q (QTC?) of .7 is considered ideal for a sealed box, but making any more sense out of the values eludes me. i researched the cheapest rubber surround dayton & goldwood woofers & subwoofers that partsexpress carries because either woofers are more expensive elsewhere, or don't provide frequency response curves. using each speaker's data, these are the QTC ratios, resonant frequencies, f3 frequencies and output at the f3 frequencies of each woofer in a 1.23 cubic foot enclosure.

i'd appreciate feedback from members who understand the numbers better which woofer excels in whatever the most important criteria is (are) for 20Hz efficiency. i'll be driving everything with a 150w (real world) class D amp and crossing over to 96dB mains rated down to 70Hz with passive 70Hz @ 24dB octave inline filters.

my first instinct would be to go with the Goldwood GW-12PC-4 12 inch Heavy Duty Woofer because it's rated at a whopping 97dB at 60Hz and if QTC = Q, them .68 is close to ideal for the flattest frequency response, but i wonder if such a match might have serious rolloff below that frequency.

my second best guess for which woofer to go with is the Goldwood GW-1244 inch Butyl Surround Woofer 4 Ohm because it has the highest outputs at one of the lowest f3 frequencies at 89.5dB at 44Hz, but is the 1.48 QTC too high? i hope someone here can make more sense out of these numbers than i can.

here's the numbers for each driver in the same enclosure with links to each in case you want to look at frequency responses or other parameters:

calculations are for a 1.23 cubic foot per half dual 12 inch box

Dayton Audio DC300-8 12 inch Classic Woofer $40
QTC = .82
resonant frequency = 57.07
F3 = 50.17
86dB @ 50Hz
Dayton Audio DC300-8 12" Classic Woofer

Goldwood GW-1248 12 inch Butyl Surround Woofer 8 Ohm $50
QTC = 1.99
resonant frequency = 66.4
F3 =44.74
85dB@45Hz
Goldwood GW-1248 12 inch Butyl Surround Woofer 8 Ohm

Goldwood GW-1244 12 inch Butyl Surround Woofer 4 Ohm $50
QTC = 1.43
resonant frequency = 65.52
F3 = 44.1
89.5dB @ 44hz
Goldwood GW-1244 12 inch Butyl Surround Woofer 4 Ohm

Goldwood GW-12PC-4 12 inch Heavy Duty Woofer 4 Ohm $70
QTC = .68
resonant frequency = 57.98
F3 = 59.7
97dB@60Hz (?)
Goldwood GW-12PC-4 12 inch Heavy Duty Woofer 4 Ohm

Goldwood GW-12PC-8 12 inch Heavy Duty Woofer 8 Ohm $70
QTC = .91
resonant frequency = 61.36
F3 = 50.52
91dB@50Hz
Goldwood GW-12PC-8 12 inch; Heavy Duty Woofer 8 Ohm

Dayton Audio DS315-8 12 inch Designer Series Woofer Speaker $76
QTC = .73
resonant frequency = 57.11
F3 = 55.26
85.5dB @ 55Hz
Dayton Audio DS315-8 12 inch Designer Series Woofer Speaker

Dayton Audio SD315A-88 1 inch DVC Subwoofer $60
QTC = .76
resonant frequency = 56.02
F3 = 52.16
88dB@52Hz
Dayton Audio SD315A-88 12" DVC Subwoofer

Dayton Audio DCS305-4 12 inch Classic Subwoofer 4 Ohm $85
QTC = .76
resonant frequency = 46.9
F3 = 43.03
85.5dB@43Hz
Dayton Audio DCS305-4 12 inch Classic Subwoofer 4 Ohm

OK... the forum let me re-edit the original post today so it's a lot easier to read now.
 
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By deciding on a sealed, compared to ported or horn loaded cabinets, you are leaving 3 to 6 dB efficiency behind, your system will require twice to four times the batteries and amplification. 150 watts won't be very impressive unless you use a lot (2 to 4 times) the sealed drivers.

Output is dictated by displacement. If you want 20 Hz response in sealed enclosures, look for speakers with an Fs around 20 Hz.
 
Hi,

Forget 20Hz for an outdoor subsystem, no-one will hear it.
Even a good 40Hz is a very dubious target being practical.

Being practical, what you want outdoors is as loud as possible
in the area centred around 80Hz. Many sealed 4x12's for bass
guitar are built like this, with high efficiency / PA type drivers.

The sealed box Q is nearly always above 0.7, around 1.0 to 1.1.
to give a bass bump in the 80Hz region. FWIW outdoors you
can get away with a bigger bump than is possible indoors.

YMMV but I'd optimise max SPL @ 80Hz with your amplifier.

Whilst you can highpass the mains at 70Hz, run the subs
higher, say to 150Hz slow to bolster the mains lower bass.

rgds, sreten.
 
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bass thump

Banned
2016-04-19 12:43 pm
By deciding on a sealed, compared to ported or horn loaded cabinets, you are leaving 3 to 6 dB efficiency behind, your system will require twice to four times the batteries and amplification. 150 watts won't be very impressive unless you use a lot (2 to 4 times) the sealed drivers.
right. that's why i'm going with 4 x 12 inch subs, to get a 6dB boost and to move as much air as possible with a system i can fit between a 29 inch wide wheelbase. i'm also fully aware i'd get more extension if i went with a ported setup, but i DESPISE the sloppy marshmallow sound of ports. i'm not looking for boom, i'm looking for thump, and nothing hits bass drum thwacks like sealed woofers (the smaller the better... i got into hifi because the bass on a friend's pair of infinity 5 1/4 minis was tighter than any i heard before. i like speed. only planars do bass better by my standards)

Forget 20Hz for an outdoor subsystem, no-one will hear it.
i don't know about that. i could CLEARLY hear 15Hz test tones through the 4 hifonics subs i was breaking in and had to go all the way down to 8Hz to be able to silently blast them. even at 10Hz i could hear cone flap. i know that MOST bass tracks only go down to 30Hz, but the more extension the better and as far as i can tell with headphones, the continuous bass tone in woofer cooker is infrasonic and meant more to be felt than heard.
https://www.youtube.com/watch?v=EUjrW1J2obs

not true at all. i used to roll around with this system that had only 10wpc real world, with 85dB 5 1/4 inch 2 ways with their ports plugged and managed to get a sunbathing woman up and dancing from about 100 feet away on a bike path, so she heard it. the systems main purpose will be close quarters dancing and some club night and tailgate party cruising as well as making bicycles look cooler than cars. when i had the saddlebag system, once this busty MILF came up to me and started freakin' on my leg so hard it was a challenge to keep the bike from tipping over. you just can't get THAT kind of interaction with a car system. people go nuts over bike systems. i just cruised with someone who has a 2 x 12 system last week and everywhere we went people cheered and danced even if the music was mediocre at best.

i'm not trying to SPL drag race here, just get the most output possible from 36 volts worth of 12v 7a batteries as soon as possible and as affordable as possible. i have A LOT of gear to buy still including the trailer itself, and not a stack of money to finance it with.

YMMV but I'd optimise max SPL @ 80Hz with your amplifier.
that would be 10Hz higher than my crossover frequency. again, i'm looking for the highest output at the deepest frequency possible with bass robbing acoustic suspension tech. if i only needed 80Hz, i could just stick with my 96dB 8 inch proel 2 ways which are rated down to 70Hz, but they are not going to be able to move enough air, especially with 70 real world watts per channel.

I'm guessing you'd need a few times that power if you want anything to be appreciably loud
sure, that'd be nice, but i don't want to be hauling 6 lead acid batteries and can't afford litium-ion so efficiency is a priority.
 
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...i DESPISE the sloppy marshmallow sound of ports.

I'm no expert on ported enclosures. I prefer sealed also, although I've never designed for any space larger than my (indoor) living room. But from what I've read, I'd be willing to bet that the "sloppy" ported systems you've heard were probably just not aligned correctly for the application. You might not want to rule them out completely, since you have some design goals working against each other here, as others have mentioned. Perhaps someone else can provide tips on a good ported alignment to shoot for that would meet your needs.

Good luck,

-- Jim
 

bass thump

Banned
2016-04-19 12:43 pm
the 2x100w with 96dB mains, 1x200w with 4 x 12 subs trailer will most definitely outclass this 10wpc with 85dB 5 1/4 inch woofing system by a mile, and the saddlebag system was good enough, if not awe inspiring
quarterview1024.jpg


I'm no expert on ported enclosures. I prefer sealed also, although I've never designed for any space larger than my (indoor) living room. But from what I've read, I'd be willing to bet that the "sloppy" ported systems you've heard were probably just not aligned correctly for the application. You might not want to rule them out completely, since you have some design goals working against each other here, as others have mentioned. Perhaps someone else can provide tips on a good ported alignment to shoot for that would meet your needs.
NEVER going to happen, EVER. i despise ported speakers. they are enemies of sound quality that should be eradicated from the face of the earth like cancer as far as i'm concerned. LOL i'm never going to sell out like freakin' infinity and boston acoustics did. i'll never forgive them for that. 5 1/4 sealed infinitys (run full range at that) were the FIRST speakers i'd heard that really got me excited, and i heard JBL towers all the way up to $5,000 klipsch lascalas at 4 different hifi stores, but it was the sheer speed and clarity as well as imaging of sealed 5s that blew me away. it was then and there that i came to the conclusion that anything bigger and more expensive than those $125 two ways was a ripoff, but subs are needed if you want full range. my bias since then hasn't changed one iota.

SQ for life!
hahahahahahahaha

i'm totally willing to accept WHATEVER the limitations of my trailer system will be, but i'd like to squeeze whatever 30Hz SPL i can within those limits. 3 dB = doubling of amp power afterall.

as far as i can tell, THIS looks like the best driver for the job:
Goldwood GW-1244 12 inch Butyl Surround Woofer 4 Ohm $50
QTC = 1.43 (will make the woofer ring at resonance?)
resonant frequency = 65.52
F3 = 44.1
89.5dB @ 44hz (95.5dBW x 4 and 116dB max at 44Hz @ 200w)
Goldwood GW-1244 12 inch Butyl Surround Woofer 4 Ohm
 
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You don't really hear those low frequencies, you feel them. What you heard is most likely harmonics. Worthwhile output at 40 Hz takes a big box and an efficient driver. Efficiency is a win-win-win thing, since it allows for lower amp power, longer battery life, less power compression, and less risk of frying the woofer.
 

bass thump

Banned
2016-04-19 12:43 pm
Also I'd forget about a passive LPF - build something active to go pre-amplifiers.
i'm not skilled at electronics. i tried looking into DIY active crossovers, and was in way over my head. i can handle designing and building a passive speaker crossover, but the math and electronics comprehension needed to build an active crossover is just too much for me. that, and even at the DIY level, active crossovers are expensive. then there's the issue of having to add even MORE batteries to accommodate another voltage besides the 36v system voltage, further complicating it, driving the price up, and weighing everything down. with 3 lead acid batteries, 2 car boxes and mains that are pretty heavy themselves, i'll be hauling a lot 20 miles or more at a stretch.

passive crossovers are simple, cheap, and don't require additional batteries. it's just too bad that i'll be buying 2 when i only need one. besides, a passive crossover is closer to a straight wire than an active circuit is it not? passive preamps, especially transformer coupled ones, are the absolute most transparent. it would stand to reason that the same principles would apply to crossovers... no gain stages to distort, just subtractive efficiency, much like sealed subs. i really like following the KISS principle.
 
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i'm not skilled at electronics. i tried looking into DIY active crossovers, and was in way over my head. i can handle designing and building a passive speaker crossover, but the math and electronics comprehension needed to build an active crossover is just too much for me. that, and even at the DIY level, active crossovers are expensive. then there's the issue of having to add even MORE batteries to accommodate another voltage besides the 36v system voltage, further complicating it, driving the price up, and weighing everything down. with 3 lead acid batteries, 2 car boxes and mains that are pretty heavy themselves, i'll be hauling a lot 20 miles or more at a stretch.

passive crossovers are simple, cheap, and don't require additional batteries. it's just too bad that i'll be buying 2 when i only need one. besides, a passive crossover is closer to a straight wire than an active circuit is it not? passive preamps, especially transformer coupled ones, are the absolute most transparent. it would stand to reason that the same principles would apply to crossovers... no gain stages to distort, just subtractive efficiency, much like sealed subs. i really like following the KISS principle.

I recently built an active mono crossover on some old perfboard with components I had floating around in my junk board - NE5532, a 30V CT transformer, couple of diodes for rectification, etc. Whole thing cost me under $30 including the enclosure, with maybe an hour put into it. If you can build a subwoofer enclosure, you can do basic electronics. Active is much, much easier to implement than passive as you don't have to worry about the effects of speaker impedance - not to mention I just found the 'correct' inductors you'd need for a 24db/octave filter at $75 each.

I strongly suggest you need to rethink your plans
 
NEVER going to happen, EVER. i despise ported speakers. they are enemies of sound quality that should be eradicated from the face of the earth like cancer as far as i'm concerned. LOL i'm never going to sell out like freakin' infinity and boston acoustics did. i'll never forgive them for that.
sure, that'd be nice, but i don't want to be hauling 6 lead acid batteries and can't afford litium-ion so efficiency is a priority.
i'd appreciate feedback from members who understand the numbers better which woofer excels in whatever the most important criteria is (are) for 20Hz efficiency.

Well first, these statements are antithetical. Sealed subwoofers have abhorrently low sensitivities. There is absolutely no way to get appreciable 20hz output outdoors with 4 sealed subs outdoors on 150w. Even if you pick a more realistic F3 like 60hz, you're still way behind a ported system on output.

Second, you're welcome to have whatever strange convictions you want, but you're demonstrating some pretty serious willful ignorance when it comes to ported systems. There's nothing inherently wrong with the sound quality of ported boxes, though I will admit it's far more likely to hear a very poorly designed one and develop a bias against them.

Given what you're trying to do, my serious suggestion is to simply build a 3015lf loaded SS15 cabinet. It is nearly 103db 1watt/1m sensitive to 60hz. Even with the meager power input you will get some very useable output. It's reasonably compact, and very light. http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge.html

And forget about doing a passive crossover. For what you'll end up spending on components, you could buy a brand new class D amp with built in crossover for less.
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge.html
 
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i'm vaguely familiar with thiele small parameters eg. a system Q (QTC?) of .7 is considered ideal for a sealed box, but making any more sense out of the values eludes me. i researched the cheapest rubber surround dayton & goldwood woofers & subwoofers that partsexpress carries because either woofers are more expensive elsewhere, or don't provide frequency response curves. using each speaker's data, these are the QTC ratios, resonant frequencies, f3 frequencies and output at the f3 frequencies of each woofer in a 1.23 cubic foot enclosure.

A sealed box qtc of 0.7 is not "ideal", ideal depends on the job at hand. In your case 0.7 qtc would make sense since the job at hand is a requirement for a sealed box playing outside (no boundary reinforcement or room gain).

A 0.7 qtc sealed box is a "max flat" design in which the frequency response extends as low as possible while remaining as flat as possible. With sealed woofers this usually still results in a fairly high f3.

This high f3 is EXACTLY why "audiophiles" prefer sealed boxes with a qtc of 0.7 or less and don't like resonant enclosures. What you hear is mostly just frequency response.

A ported box with the same frequency response as a sealed box will sound very much like a sealed box, and group delay from port resonance is largely inconsequential below 40 hz tuning.

Therefore it is strongly advised (by several people including myself) that you drop the silly sealed box requirement.

The reason most people that don't like ported boxes dislike them is frequency response, not port resonance issues. Most ported designs are "max flat", especially those designed and built by diy'ers. "Max flat" ported boxes usually sound way too boomy in a room because the design doesn't consider the fact that there will be room gain. Outside, however, a "max flat" ported design will sound more accurate. And of course ported boxes can have both a low tuning AND a high f3 just like a sealed box, so with the same frequency response as a sealed box they can sound very much like a sealed box.

i'd appreciate feedback from members who understand the numbers better which woofer excels in whatever the most important criteria is (are) for 20Hz efficiency. i'll be driving everything with a 150w (real world) class D amp and crossing over to 96dB mains rated down to 70Hz with passive 70Hz @ 24dB octave inline filters.

A 70 hz 24 db/oct crossover will be insanely expensive. Especially considering that you could buy a car audio active crossover for about $15 and power it with a small battery pack. I'm not going to look up models and power requirements right now, but a few AA batteries wired to produce 12 volts would probably power a car audio active crossover for a few days, 24 hours a day. They draw very little power.

Also, if you don't know how to measure (or at least simulate) frequency response and impedance curves and then turn those measurements into .frd and .zma files and use a real crossover design program to design the passive crossover it's very unlikely that you will get optimal results.

my first instinct would be to go with the Goldwood GW-12PC-4 12 inch Heavy Duty Woofer because it's rated at a whopping 97dB at 60Hz and if QTC = Q, them .68 is close to ideal for the flattest frequency response, but i wonder if such a match might have serious rolloff below that frequency.

my second best guess for which woofer to go with is the Goldwood GW-1244 inch Butyl Surround Woofer 4 Ohm because it has the highest outputs at one of the lowest f3 frequencies at 89.5dB at 44Hz, but is the 1.48 QTC too high? i hope someone here can make more sense out of these numbers than i can.

This is where a simulator comes in very handy. I can sim stuff if you like but it's best to learn to do your own sims, it will be very useful.

Sealed box qtc is ALWAYS higher than driver qts UNTIL/UNLESS box size is infinite (with infinite sometimes being defined as at least 10x Vas). If the box size is much smaller than 10x Vas then the sealed box qtc will be much larger than driver qts.

Once you simulate a few different situations (or have some sims done for you) you will realize how ridiculous your goals are. The 20 hz requirement from a small sealed box will not produce an audible 20 hz tone (you will hear distortion though if you turn it up enough). The passive crossover requirement is more expensive and much worse than a cheap active solution.

You can lower qtc by a moderate amount (not much) with stuffing.

right. that's why i'm going with 4 x 12 inch subs, to get a 6dB boost and to move as much air as possible with a system i can fit between a 29 inch wide wheelbase. i'm also fully aware i'd get more extension if i went with a ported setup, but i DESPISE the sloppy marshmallow sound of ports.

Again, what you despise is the frequency response of the ported systems you have heard. It's not a port or resonance problem, it's frequency response.

i'm not looking for boom, i'm looking for thump, and nothing hits bass drum thwacks like sealed woofers (the smaller the better... i got into hifi because the bass on a friend's pair of infinity 5 1/4 minis was tighter than any i heard before. i like speed. only planars do bass better by my standards)

Speed is an "audiophile" term that doesn't mean what you think. Again, it's frequency response. The high f3 of a sealed box sounds "faster" and "cleaner", less boomy than the much lower f3 of the usual ported box system.

i'm not trying to SPL drag race here, just get the most output possible from 36 volts worth of 12v 7a batteries as soon as possible and as affordable as possible.

If this is the ultimate goal you need to drop the silly sealed box requirement.

I didn't bother quoting your personal anecdotes about frisky women responding to your mini monitor system strapped to your bike, but suffice to say that if you think you are going to get any audible output at 20 hz from a system you can bike around easily with the budget, size and power requirements you mentioned, you are nuts.

sure, that'd be nice, but i don't want to be hauling 6 lead acid batteries and can't afford litium-ion so efficiency is a priority.

Again, if efficiency is a priority you are going about this ALL WRONG.

the 2x100w with 96dB mains, 1x200w with 4 x 12 subs trailer will most definitely outclass this 10wpc with 85dB 5 1/4 inch woofing system by a mile, and the saddlebag system was good enough, if not awe inspiring

LOL, that's awe inspiring?

A good deal of people on this forum know what they are talking about. Continuing to ignore good advice will get you exactly where you are headed - a heavy, very inefficient system that lonely middle age women hanging out on bike paths might appreciate but people with knowledge about electronics and speakers will laugh at.

People here will help you design what you claim you want (high efficiency) but you have to listen and loosen up your conflicting requirements.
 
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bass thump

Banned
2016-04-19 12:43 pm
Well first, these statements are antithetical. Sealed subwoofers have abhorrently low sensitivities. There is absolutely no way to get appreciable 20hz output outdoors with 4 sealed subs outdoors on 150w. Even if you pick a more realistic F3 like 60hz, you're still way behind a ported system on output.
i KNOW i'm going to lose bottom octave output, but as far as i'm concerned, the gains in clarity are well worth it.

i have a pair of high efficiency speakers in sealed 12 inch 2 way cabs i picked up in a thrift shop that might be as little as 3/4 cubic foot, and i found the bass from those to be more than satisfying, particularly in how undistorted and at ease they sounded indoors, probably driven by less than a watt most of the time and even then, i had to roll the bass off to -10 on my panasonic class D receiver. i'm never going to turn to the distortion loving dark side. you can't make me, so there! hahahahahaha
 

bass thump

Banned
2016-04-19 12:43 pm
Second, you're welcome to have whatever strange convictions you want, but you're demonstrating some pretty serious willful ignorance when it comes to ported systems. There's nothing inherently wrong with the sound quality of ported boxes, though I will admit it's far more likely to hear a very poorly designed one and develop a bias against them.
how very very very UNTRUE:

from:
KICKER | Ported Enclosure Pros and Cons
(they have SCIENTISTS there and everything)

ported woofer cons

1 - Total loss of cone control below vent tuning, which can result in high distortion and driver mechanical failure. (aka overhang)
2 - Midrange sound coming from inside the box through the vent can produce unpleasant sound coloration.
3 - Vented enclosures are more sensitive to changes such as temperature, humidity and driver fatigue.
4 - Enclosure design is more complex and the enclosure itself must be more solidly constructed because internal pressure at frequencies around vent tuning can be nearly twice as high as a sealed enclosure.
5 - Vented enclosures usually don’t sound as fast as sealed boxes because the resonant effects of the vent tuning which is always slightly out of phase with the driver’s output.

not to mention:
- timing delays caused by soundwaves having to take the scenic route to get to the listener
- port chuffing
- one note bass
- resonant tuning adds harmonics that don't actually exist in a recording just like blowing on a bottle sounds NOTHING like the source, your breath

i might not know electronics, but i've known the SCIENCE behind WHY little infinity monitors have so much better bass than SLOPPY ported 15s since around 1985.
- lower moving mass
- air spring
- near total backwave cancellation

these aren't opinions, these are scientific FACTS i have to argue with EVERY single distortion lover who has a problem with my preference for sound quality over quantity and no matter how much science you throw at them, they'll still argue and resort to name calling before admitting they like distortion.

there's only ONE con for sealed boxes, less ouput at the lowest frequencies
but at least that output is REAL and not a hideous artificial distortion artifact. ports tell much lies, plug them and all you hear is the truth.

Given what you're trying to do, my serious suggestion is to simply build a 3015lf loaded SS15 cabinet.

no. i won't do 15" woofers. my FAVORITE woofers are feather light planars (nothing snaps a bass drum hit faster), followed by 8 inch cones. i'd rather go the other way and use 10 inch subs, but they don't move as much air as 12s, so using 12s is a compromise between sound quality and moving air. if power wasn't an issue, i'd go for even higher sound quality and speed with isobaric loading.

Once you simulate a few different situations (or have some sims done for you) you will realize how ridiculous your goals are. The 20 hz requirement from a small sealed box will not produce an audible 20 hz tone

sure, a sim would produce a FULL frequency curve that could be compared against another curve, but the box calculations i did are a rougher sim, and a sim can't tell you how fast a woofer can snap or how distorted its resonances sound.

Again, what you despise is the frequency response of the ported systems you have heard. It's not a port or resonance problem, it's frequency response.
NO! NO! NO! NO! it's the thick bloated marshmallow sound and not the EQ at all! the last two bookshelf speakers i bought were ported with plugs. in both cases, i preferred the tighter, cleaner sound with the ports plugged even though it lowered the bass extension where MORE would be preferable. i can't stand transient smearing. i like speed and clarity... then, just add some bass boost to get back what you've lost. arguing that ports don't distort is continuing a LIE that both SCIENCE, and CRITICAL LISTENERS know to be false. read some reviews for high end studio monitors, and the subject of port distortion comes up regularly.

just like you can't argue that global warming isn't real, you can't argue that ports don't distort. the science was settled decades ago.

more SCIENCE from a speaker manufacturer (whose bread and butter happens to be high efficiency drivers designed for ported boxes BTW)

http://www.eminence.com/2011/06/sealed-vs-ported-enclosures/
There are some disadvantages to ported enclosures. Transient response is poor compared to a sealed enclosure. The result is decreased accuracy. Also, there’s less control below the box tuning, which allows the cone to move more freely. This can result in damage to the speaker mechanically, a phenomenon known as over-excursion.

wishful thinking because YOU prefer the sound of ported speakers will NEVER make ALL of the forms of distortion they induce go away. i did my homework on the subject DECADES ago and have tried to keep up to date wherever possible. BTW, those little infinity 2 ways WEREN'T my favorite speakers back in the day. once i learned to ignore ported speakers, my dream speakers were boston acoustic towers with 2 x 8 inch woofers and a really fast 3 1/2 inch midrange cone. oh the clarity!
 
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how very very very UNTRUE:

from:
KICKER | Ported Enclosure Pros and Cons
(they have SCIENTISTS there and everything)

ported woofer cons

1 - Total loss of cone control below vent tuning, which can result in high distortion and driver mechanical failure. (aka overhang)
2 - Midrange sound coming from inside the box through the vent can produce unpleasant sound coloration.
3 - Vented enclosures are more sensitive to changes such as temperature, humidity and driver fatigue.
4 - Enclosure design is more complex and the enclosure itself must be more solidly constructed because internal pressure at frequencies around vent tuning can be nearly twice as high as a sealed enclosure.
5 - Vented enclosures usually don’t sound as fast as sealed boxes because the resonant effects of the vent tuning which is always slightly out of phase with the driver’s output.

not to mention:
- timing delays caused by soundwaves having to take the scenic route to get to the listener
- port chuffing
- one note bass
- resonant tuning adds harmonics that don't actually exist in a recording just like blowing on a bottle sounds NOTHING like the source, your breath

i might not know electronics, but i've known the SCIENCE behind WHY little infinity monitors have so much better bass than SLOPPY ported 15s since around 1985.
- lower moving mass
- air spring
- near total backwave cancellation

these aren't opinions, these are scientific FACTS i have to argue with EVERY single distortion lover who has a problem with my preference for sound quality over quantity and no matter how much science you throw at them, they'll still argue and resort to name calling before admitting they like distortion.

there's only ONE con for sealed boxes, less ouput at the lowest frequencies
but at least that output is REAL and not a hideous artificial distortion artifact. ports tell much lies, plug them and all you hear is the truth.


no. i won't do 15" woofers. my FAVORITE woofers are feather light planars (nothing snaps a bass drum hit faster), followed by 8 inch cones. i'd rather go the other way and use 10 inch subs, but they don't move as much air as 12s, so using 12s is a compromise between sound quality and moving air. if power wasn't an issue, i'd go for even higher sound quality and speed with isobaric loading.

LOL, really? Kicker? You might be surprised how unscientific their "scientists" are. And they are famous for providing drivers and box plans that put a high(ish) frequency spike in response about 10 db or so, the definition of one note bass.

Point for point (on a few of your points) -

Loss of cone control below vent tuning - this is pretty funny. You tune your vent to produce the lowest notes you want to be able to play and then use a high pass filter to get rid of everything below that. This results in almost zero distortion below tuning.

Midrange sound coming through the vent is controllable both mechanically and electrically. If you have midrange sounds coming out of your subwoofer something is VERY wrong.

Vented enclosures are no more sensitive to temperature, humidity and driver fatigue (when used properly) than sealed boxes.

Ported design is not difficult and no harder to construct than a sealed box.

As I mentioned, "fast" bass has nothing to do with port resonance problems or group delay. It's all about frequency response and a ported box can sound very much like a sealed box if they have the same frequency response.

Port chuffing, one note bass and harmonic problems are all indicators of bad design, not an inherent problem with ports.

These "scientific facts" are nonsense. All of it is nonsense.
 
how very very very UNTRUE:

...

these aren't opinions, these are scientific FACTS i have to argue with EVERY single distortion lover who has a problem with my preference for sound quality over quantity and no matter how much science you throw at them, they'll still argue and resort to name calling before admitting they like distortion.

I don't have time to go over them point-by-point, but most of the items you cited are caused by incorrect application of the reflex concept and therefore completely avoidable; and some of the others are indeed simply someone's opinion. And I'm not sure why you feel the need to bring up name calling. That's not likely to happen here, even thought many diyAudio members (including some on this thread) have forgotten more than you or I will ever know about this stuff. And yes, some of them are "scientists" too.

there's only ONE con for sealed boxes, less ouput at the lowest frequencies but at least that output is REAL and not a hideous artificial distortion artifact. ports tell much lies, plug them and all you hear is the truth.
You obviously have strong feelings about the sound of sealed enclosures. Here's the problem: What you're trying to accomplish here is pretty much the opposite of how anyone else would attempt to approach your project. And trust me, it's not for lack of knowledge; in fact it's just the opposite, regardless of what you believe. But because of this, you're not likely to find much useful advice here for doing what you want to do, because no one else has bothered trying it. Does that make sense?

-- Jim
 
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no. i won't do 15" woofers. my FAVORITE woofers are feather light planars (nothing snaps a bass drum hit faster), followed by 8 inch cones. i'd rather go the other way and use 10 inch subs, but they don't move as much air as 12s, so using 12s is a compromise between sound quality and moving air. if power wasn't an issue, i'd go for even higher sound quality and speed with isobaric loading.


You are proving you have no idea what you are talking about. You continue to talk about "faster" and now you are adding the ridiculous notion that isobaric is faster and higher quality.

There are forums that would welcome these opinions with open arms. It is a very "audiophile" perspective. But the people on this forum are generally much more educated and this stuff just won't fly here.


sure, a sim would produce a FULL frequency curve that could be compared against another curve, but the box calculations i did are a rougher sim, and a sim can't tell you how fast a woofer can snap or how distorted its resonances sound.


You might be surprised what a sim can tell you. The "calculations" you did mean nothing, you have no idea what qtc would be. A sim will tell you all that, and if a sim shows the frequency response of a sealed and ported box with the same driver are the same they will sound much the same.

NO! NO! NO! NO! it's the thick bloated marshmallow sound and not the EQ at all! the last two bookshelf speakers i bought were ported with plugs. in both cases, i preferred the tighter, cleaner sound with the ports plugged even though it lowered the bass extension where MORE would be preferable. i can't stand transient smearing. i like speed and clarity... then, just add some bass boost to get back what you've lost. arguing that ports don't distort is continuing a LIE that both SCIENCE, and CRITICAL LISTENERS know to be false. read some reviews for high end studio monitors, and the subject of port distortion comes up regularly.

just like you can't argue that global warming isn't real, you can't argue that ports don't distort. the science was settled decades ago.

The bloated marshmellow sound went away when you plugged the ports BECAUSE YOU CHANGED THE FREQUENCY RESPONSE DRAMATICALLY. It has nothing to do with port resonance issues or group delay.

Badly designed ports can distort. Well designed ports won't distort AND they will allow the driver to produce a boatload more spl before IT distorts.

You've demonstrated that you have at best a very weak grasp of the concepts involved here.
 
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