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Sealed vs Ported vs Other-types...

FrantzM

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#1
Hi

Call me a bass head if you will. I have posted many times my preference for multiple subwoofers, either Harman-Style or Geddes-style. I believe the best bass in a room can only be obtained with multiple subwoofers.
For the longest time, I have held that sealed subwoofers are to be preferred. Mostly based on anecdotes and audiophile sayings. No hard proof.
I use currently in a 6 x 4 x 3 meter concrete room a trio of Parts Express SUB-1500 subwoofers, they cost shipped $200 each and I can't fault them in my HT. No port noise , no shuffling or clicking simply prodigious bass in my room reaching 18 Hz at 104 SPL Hz, on my tests at the LP.. I didn't care to measure the limits it was plenty loud, making me a bit dizzy and shaking everything in the house , call these anecdotes but ...
I am building a 2 channel system and was thinking getting a trio of SVS SB-1000 or Rythmik L12, all of these controlled via a miniDSP 2 x 4 HD. That would be a cash outlay of around $1500 shipping included.... A similar room 6 x 5 x 2.5 meters. Insulated and less openings... The system is for music , I do listen once in a while at spirited levels but 100 dB for me is super loud, intolerable, so ...

On one side $600 for 3 subs. the Parts Express way or ...
On the other $1500... The Rythmik, SVS way"
Which way to go?

And the more fundamental question: Are sealed subwoofers inherently superior to ported?
 

Soniclife

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#2
And the more fundamental question: Are sealed subwoofers inherently superior to ported?
Without DSP they are clearly different. I think your real questions is if you are using DSP, does it matter.
 

CDMC

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Sealed subwoofers hold an advantage in group delay and transient response. The thing is that a properly designed sealed and vented subwoofer will both have group delay below the level of audibility as will be the slightly delayed transient response. Many claim that a sealed subwoofer provides better midbass, but that is a misconception. Without equalization, a sealed subwoofer will roll off sooner at 12db an octave, while a vented will extend further down until its tuned frequency and then drop at 24db an octave. This results in naturally higher level of midbass in the sealed enclosure. In addition, since the sealed subwoofer often has less output in the 20-50hz range, it stimulated room modes less resulting in a tighter sound. Again, this is without equalization or DSP, which is getting rarer and rarer.

On average, vented subwoofers are about 3db more efficient in the low bass, which is an equivalent of double the power. There is no free lunch, as once you get below their tuned frequency output drops like a rock and since the woofer is unloaded, require a high pass filter. This is the reason that you see a dichotomy in the home theater arena. Vented works great for most applications, but for those guys that want high bass levels below 20hz, they need a large number of sealed subwoofers, as it is below the tuned frequency of virtually any vented subwoofer.

Finally, a sealed subwoofer can be easier to integrate with your main speakers as there is less phase change through the operating range so less opportunity for phase issues between your mains and the subs. My understanding is the phase issues become less and less of an issue as you add more subwoofers.

So what is the answer to your question? Both work well, the execution is more important than whether the design is vented or sealed. I have three Rythmiks, an L12 and two F15hps (one in my office, the two others in the main system). While I believe the F series sounds a bit drier and tighter, equalizing the subs to get rid of peaks has a far larger effect on the perceived tightness than the difference between the two models.
 

levimax

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#4
Hi

And the more fundamental question: Are sealed subwoofers inherently superior to ported?
Sealed are inherently much bigger physically (for same FR)
Sealed are inherently easier to design

Like everything in audio it is more how well a design is executed rather than the what approach is used. Having said that I have found "sealed" speakers/ subwoofers in general to be easier to integrate into a room to get pleasing deep bass... probably because there are less variables without a port. If you can live with the size I think sealed are a safer bet.
 
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FrantzM

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Thread Starter #5
I will use a miniDSP 2 x 4 HD as DSP/ EQ. In any case whether it is a sealed or ported solution. I’d like to spend the minimum. Mains to be Yamaha NS-1000M with high pass at 60 Hz. From there I’m flying blind. I’ll learn through this thread and others.
 

blueone

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#6
Sealed are inherently much bigger physically (for same FR)
Sealed are inherently easier to design

Like everything in audio it is more how well a design is executed rather than the what approach is used. Having said that I have found "sealed" speakers/ subwoofers in general to be easier to integrate into a room to get pleasing deep bass... probably because there are less variables without a port. If you can live with the size I think sealed are a safer bet.
Typo - you mean ported subs are much bigger physically.
 

blueone

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#8
To get the same FR and SPL a sealed sub needs to be much bigger physically ..... the whole point of a port is to get lower FR from a smaller enclosure
This is an unusual way of looking at it. Generally the subwoofer industry classifies subwoofers by driver size, they even name them that way. For all cases I can think of, ported enclosures for a given driver size are larger than a similarly sized driver in a sealed enclosure. Yes, the sealed version will generally have higher distortion and not play as loudly, but it will be smaller. In fact, smaller enclosure sizes are probably the biggest selling point of sealed subwoofers. On the other hand, I can't argue with you that to achieve similar output level and distortion from a sealed design you need a larger enclosure, and probably a larger driver.
 

levimax

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#9
This is an unusual way of looking at it. Generally the subwoofer industry classifies subwoofers by driver size, they even name them that way. For all cases I can think of, ported enclosures for a given driver size are larger than a similarly sized driver in a sealed enclosure. Yes, the sealed version will generally have higher distortion and not play as loudly, but it will be smaller. In fact, smaller enclosure sizes are probably the biggest selling point of sealed subwoofers. On the other hand, I can't argue with you that to achieve similar output level and distortion from a sealed design you need a larger enclosure, and probably a larger driver.
Yes marketing and DSP and ports and consumer demand have made things kind of confusing. If I have a point anymore it would be a sealed subwoofer with a big driver and a big box is easy to design (especially for DIY) and integrate..... but there are certainly more important considerations than sealed vs ported.
 

digitalfrost

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#10
These days, when amplifier power, multichannel and DSP are easily available, I see no reason to bother with anything but closed subs/dipoles.

You can use as many as you like, you can pump enough power into them for cheap, and to organize and integrate you have various DSP solutions. Bassreflex is too much hassle for me. Especially if you want them go down really deep, you end up with huge port lenghts (unless you have huge enclosures anyway), and then you can't (shouldn't) boost below tuning frequency.

Sealed is much easier to design - and a much more stable system - and to propely integrate you need DSP anyway. If it's not loud enough, use more or bigger drivers. Bassreflex seems a crutch to me that is just not necessary anymore.

e: Also. Proper bass-reflex subwoofers cannot be small. A proper sub needs at minimum 40hz tuning frequency IMHO, better less for the movie people. Try to fit that in a small enclosure. If you build a BR sub properly, you have this monster that plays loud as hell, but you will be using multiple subs anyway and power is cheap. I just don't see it.

What is the price of a hole in the box?
 
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q3cpma

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#11
These days, when amplifier power, multichannel and DSP are easily available, I see no reason to bother with anything but closed subs/dipoles.

You can use as many as you like, you can pump enough power into them for cheap, and to organize and integrate you have various DSP solutions. Bassreflex is too much hassle for me. Especially if you want them go down really deep, you end up with huge port lenghts (unless you have huge enclosures anyway), and then you can't (shouldn't) boost below tuning frequency.

Sealed is much easier to design - and a much more stable system - and to propely integrate you need DSP anyway. If it's not loud enough, use more or bigger drivers. Bassreflex seems a crutch to me that is just not necessary anymore.

e: Also. Proper bass-reflex subwoofers cannot be small. A proper sub needs at minimum 40hz tuning frequency IMHO, better less for the movie people. Try to fit that in a small enclosure. If you build a BR sub properly, you have this monster that plays loud as hell, but you will be using multiple subs anyway and power is cheap. I just don't see it.

What is the price of a hole in the box?
Genelec's LSE subs show that big entreprises with the means can solve those size problems very well, but it certainly needs a lot of R&D to not botch a port. The reward is something all the amp power in the world can't give you: sensitivity and lower distorsion (including THD and IMD). Really, well implemented bass reflex is literally adding another channel to your speaker, and I hope I don't have to explain why more ways has major advantages when aiming for fullrange and high SPL.
 

digitalfrost

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#12

q3cpma

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#13
Yeah, the design isn't really apparent.


I'm not sure how much THD and IMD matter with subwoofers. I tought we get less sensitive to these things and we go down the frequency band. But in technical principle, I understand you and I agree.
Well, "less distorsion" is a poor way to say it. Lower distorsion or excursion limit is probably better, as I mean higher SPL without reaching mechanical limits.
 

MZKM

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#14
These days, when amplifier power, multichannel and DSP are easily available, I see no reason to bother with anything but closed subs/dipoles.
For music. For movies where even 20Hz isn’t deep enough, you need to spend a ton to get a sealed sub that is happy down that low at extreme SPL.
 
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FrantzM

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Thread Starter #15
System is for music ... Trying not to repeat myself. I have come not to worry about the FR linearity when it comes to subwoofer. Maximum SPL and general distortion behavior seem to me the most important attributes. A linear 20~100 Hz plus or minus .5 dB subwoofer @ 0.5% THD and IM but that is only capable of 95 dB within its passband may not fare well as well in a room as one capable of say 15 to 100 Hz plus or minus 5 dB @ 2% THD and IM but capable of 110 dB in its passband.
I don't know how to measure Harmonic Distortion for subs or speakers for that matter, I have never heard an instance of the 3 SUB-1500 having any issue, reproducing the real low in Aquaman, Blade Runner 2049 or Interstellar ( All very loud, bass-heavy movies). I suppose they should be at ease having to reproduce the occasional 16 Hz fro an organ symphony or hip-hop ;) tracks in a medium-sized room. I simply don't know. Where I am you research a lot and buy once. We don't have the luxury of returning products, The hassle is beyond comprehension. Thus my numerous and repetitive questions :)
 

levimax

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#16
While the Genelec 7050C is an amazing piece of engineering if you look closer at the specs it only puts out ~86 db @ 30 Hz @ 1 meter and has 4% distortion. Fine for a desktop system but if you have a decent size room it is not going to cut it. Of course they have bigger models but the prices get crazy quickly.
 

jhaider

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And the more fundamental question: Are sealed subwoofers inherently superior to ported?
The way I look at there's no "superior," only "better for a given application." Here's a brief overview of the tradeoffs involved:
Bass reflect (ported or passive radiator) is more efficient right above tuning. However, the tuning frequency is a pretty hard cutoff, so there is little usable output below tuning no matter how beefy the woofer is.
Sealed is less efficient but can play lower because extension is limited by the volume displacement of the driver.
Bandpass (often marketed as "horn") just provides another element to shape the "area under the curve," i.e. efficiency and bandwidth.

And then there are open baffles with various baffle folds, and cardioid. These types of subs are less efficient, but interact with modes differently ("directivity" in the modal region of a small room is not a thing) and may but will not necessarily result in smoother response.

Also. Proper bass-reflex subwoofers cannot be small. A proper sub needs at minimum 40hz tuning frequency IMHO, better less for the movie people. Try to fit that in a small enclosure. If you build a BR sub properly, you have this monster that plays loud as hell, but you will be using multiple subs anyway and power is cheap. I just don't see it.
With passive radiators and a very strong motor driver you can make a sub that is small and goes quite low. The old Peerless XLS12 reference design is a good example: 35L (1.25 cubic feet) internal volume and useful extension to the low 20s.
 

q3cpma

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#19
While the Genelec 7050C is an amazing piece of engineering if you look closer at the specs it only puts out ~86 db @ 30 Hz @ 1 meter and has 4% distortion. Fine for a desktop system but if you have a decent size room it is not going to cut it. Of course they have bigger models but the prices get crazy quickly.
Where do you get this 86 dB from? Spec is "Maximum short term sine wave SPL output averaged from 30 to 85 Hz, measured in half space at 1 meter: 103 dB". Since the port is the highest output on the frequency response (excluding LFE channel), it's at least 103 dB at 30 Hz. Remove 6 dB for the half-space gain and you're still at 97 dB.
Not that I don't acknowledge the fact that the 7x50 serie is for nearfield.
 

richard12511

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#20
System is for music ... Trying not to repeat myself. I have come not to worry about the FR linearity when it comes to subwoofer. Maximum SPL and general distortion behavior seem to me the most important attributes. A linear 20~100 Hz plus or minus .5 dB subwoofer @ 0.5% THD and IM but that is only capable of 95 dB within its passband may not fare well as well in a room as one capable of say 15 to 100 Hz plus or minus 5 dB @ 2% THD and IM but capable of 110 dB in its passband.
I don't know how to measure Harmonic Distortion for subs or speakers for that matter, I have never heard an instance of the 3 SUB-1500 having any issue, reproducing the real low in Aquaman, Blade Runner 2049 or Interstellar ( All very loud, bass-heavy movies). I suppose they should be at ease having to reproduce the occasional 16 Hz fro an organ symphony or hip-hop ;) tracks in a medium-sized room. I simply don't know. Where I am you research a lot and buy once. We don't have the luxury of returning products, The hassle is beyond comprehension. Thus my numerous and repetitive questions :)
Yeah, subwoofers are much simpler devices than loudspeakers. As long as the distortion is low enough to be inaudible, and most of them are, that's all that matters.

Most important things to look for when it comes to the value of subs are price, extension, and max output. For the best value, Rythmik, JTR, HSU, and PSA seem to be the ones making the best subwoofers right now. SVS is not far behind, and tend to look a little better.
 
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