Sealed vs Ported Loudspeakers: Which is Better?

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Audioholics Robot
Staff member
Sealed vs ported loudspeakers, which one is better? This is an age-old question one which sparks debates not only among consumers but designers themselves. There are certainly points on each side of the argument to consider. The debate of ported vs. sealed is intrinsically relevant and interesting, regardless of the arbitrary brand involved. This article provides a historical perspective on the genesis of the sealed loudspeaker design and how it compares with conventional ported designs.


Discuss "Sealed vs Ported Loudspeakers: Which is Better?" here. Read the article.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
It looks like it will be a great article, but I got an error trying to access the second page.
 
slipperybidness

slipperybidness

Audioholic Spartan
waaaaait for it.......waaaaait for it :D
 
3db

3db

Audioholic Overlord
Ported or sealed.. who cares? :) As long as they sound good is all that matters to me.
 
j_garcia

j_garcia

Audioholic Jedi
Ported or sealed.. who cares? :) As long as they sound good is all that matters to me.
I'm sort of in the same boat and the article sort of suggests the same :) It really depends on the speaker as a whole, as the article also mentions in the closing comment

But I have heard terrific (and lousy!) systems of all types, so I'm willing to believe that it's more a matter of the designer's goals and their skill at execution that makes the difference, rather than any arbitrary design approach.
It does come down to what the designer was after and their preferences. A given designer's "style" may not be pleasing to everyone's ears regardless of how they may measure.

I also thought the comment about "they don't HAVE to be bad..." definitely hits hard at something completely different than where the article was going. There seems to be a fairly large gap in home audio these days. Where previously, almost everyone had a "decent" stereo system and the tweakers (Audioholics) still had their nice systems, today, I don't know too many people that have really nice systems and a LOT of people who just bought a basic system because their TV speakers sucked. If the general consumer doesn't demand better speakers, then the focus won't be on making better speakers in general. There will always be Audioholics, but we don't dominate the market.
 
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Irvrobinson

Irvrobinson

Audioholic Spartan
Nice article.

For years I thought sealed speakers had better bass, he says now owning absolutely fantastic ported speakers. I genuinely thought the sealed alignment sounded better overall, though now I'm thinking it's more the quality of the execution than whether it is sealed or not. I still remember hearing the Dunlavy SC-V for the first time (a sealed system) and thinking, wow, now that's awesome bass! I was also very fond of my ADS towers.

Nonetheless, the best bass *quality* I've heard is from speakers with no bass enclosure, like the Linkwitz Orion, the Carver Amazing, and the Sound Labs U-1PX. I'm often less than satisfied with the sheer level of bass output of these designs, but the bass sounds much more natural than from any enclosed bass system I've ever heard.
 
slipperybidness

slipperybidness

Audioholic Spartan
I would have liked to see some info on passive radiators included too. Perhaps in a followup.
 
TLS Guy

TLS Guy

Audioholic Slumlord
This is an age old topic, but remains an important one.

The other day in response to a members question on the advantage of an 18" driver over a 15" driver, I found I could not properly put together an answer without giving my thought on loudspeaker design and bass extension.

I would make the following additional observations.

I think total system Q has a large and almost overwhelming influence on the character of the bass in a system.

As I stated in my post I feel the total Q of the vast majority of designs before the public have total Q too high, and are incapable of really accurate "you are there" lower octave reproduction.

Every time I leave a good concert as I did last Saturday night I become even more convinced that optimal total Q 0.7 is too high and not accurate.

So how did this desired total Q of 0.7 come about? I think it his historic, as the importance of proper BSC was not understood, and mid range accuracy was much more elusive than it is now. The added warmth of the inherent resonant reproduction of total Q 0.7 and even higher, covered a multitude of sins.

As time passes I become more and more convinced, that to achieve that precise "sitting at the edge of the chair" excitement of live performance requires critically damped bass alignments. The rest just come up short.

I often ear it said, that low Q systems are all very well for orchestral, chamber and instrumental music, but what about music in the popular domain?

I designed this system to please me primarily and no one else, and reproduction of of music from the pop culture was not even on my radar.

However, mix engineers seem to be prepared to make the long journey to Benedict to check mixes and grade student projects. The reason given is bass detail and accuracy and the ability to hear what they can't on other speakers. So this has led me to believe that all genres of music benefit from critically damped speaker systems.

I have some further comments on this debate. Sealed, infinite baffle and open box designs, are inherently wasteful, however excellent they may be in other regards. What I'm getting at is that in the bass region a loudspeaker cone is a poor coupler with the acoustic space. The larger the space the worse this situation becomes.

So bass loading or acoustic transformation, if you like, is highly desirable. This becomes the biggest argument for ported speakers, as they achieve this with a reasonably sized box.

One of the curses of the commercial world is the numbers game. So everybody strives for the greatest bass extension on their spec sheet. This is a grave error. It is much better to sacrifice bass extension for control. My approach to ported design is to align for tight response an even sacrifice some port output with slightly more damping than customary.

Unfortunately I know no way of usefully augmenting a driver in a truly critically damped fashion without enclosure designs that take significant real estate and likely to raise WAF issues.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Ported or sealed.. who cares? :) As long as they sound good is all that matters to me.
I agree. Just enjoy the music and movies. Great sound is great sound. It doesn't matter how you get there as long as you get there. :D

Most speakers are ported, so I guess the ported outnumbers the sealed. No right or wrong.
 
Steve81

Steve81

Audioholics Five-0
In the spirit of the article, I started testing out the sealed mode of my PB13U last night with a couple of songs (Beach Boys: "Sloop John B", Eric Church: "Smoke A Little Smoke"). Only thing that I noticed right away was a loss of output switching from 15Hz mode to Sealed Mode; really, it's a little difficult to compare since I can't instantly switch. To be honest though, I'm not expecting a night and day difference given that the measurements show any problems in the time domain for 15Hz mode are reasonably restricted to 20Hz and below. When I get a little more time (seems to be in short supply these days), I'll fool with it a bit more and try to level the playing field a bit, ie set up the sealed mode properly in Audyssey and then listen to some tracks I'm familiar with.
 
ImcLoud

ImcLoud

Audioholic Ninja
I prefer sealed for music and ported for theater... But I never tried the same sub sealed and ported I compared my hsu to my wharfedale and the hsu is better for room shaking movie effects, but the wharfedale is better for fast, clean, realistic music bass... I also tried a larger wharfedale {15"} vs 2 of the {12"} and I preferred the dual 12's, so then I tried dual 15's and I still preferred the dual 12's... Not sure why but they sounded noticeably more responsive...
 
cpp

cpp

Audioholic Field Marshall
I really don't care one way or the other as I've heard good and bad from each design type. The ear's knows and what that pair hears is what matters most :D
 
TLS Guy

TLS Guy

Audioholic Slumlord
In the spirit of the article, I started testing out the sealed mode of my PB13U last night with a couple of songs (Beach Boys: "Sloop John B", Eric Church: "Smoke A Little Smoke"). Only thing that I noticed right away was a loss of output switching from 15Hz mode to Sealed Mode; really, it's a little difficult to compare since I can't instantly switch. To be honest though, I'm not expecting a night and day difference given that the measurements show any problems in the time domain for 15Hz mode are reasonably restricted to 20Hz and below. When I get a little more time (seems to be in short supply these days), I'll fool with it a bit more and try to level the playing field a bit, ie set up the sealed mode properly in Audyssey and then listen to some tracks I'm familiar with.
Making a speaker that can be sealed or ported, may be good marketing, but it is lousy engineering.

For any woofer optimal box sizes for a sealed and ported alignment are going to be very different. There are significant differences in driver selection and design for the two alignments.
 
Steve81

Steve81

Audioholics Five-0
Making a speaker that can be sealed or ported, may be good marketing, but it is lousy engineering.

For any woofer optimal box sizes for a sealed and ported alignment are going to be very different. There are significant differences in driver selection and design for the two alignments.
Perhaps, but the measurements for the sealed mode are hard to argue with.

Sealed Mode
Data-Bass

In sealed mode on the power compression sweep, the PB13U can deliver 105dB at 2m ground plane from 120Hz-30Hz +0 /-~2dB with quite respectable distortion (its just hitting the 5% mark at 31.5Hz), and the group delay and waterfall charts are pristine. I wouldn't exactly call it lousy engineering, although from what I've heard I'd probably stick with 15Hz tune and call it a day.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Perhaps, but the measurements for the sealed mode are hard to argue with.

Sealed Mode
Data-Bass

In sealed mode on the power compression sweep, the PB13U can deliver 105dB at 2m ground plane from 120Hz-30Hz +0 /-~2dB with quite respectable distortion (its just hitting the 5% mark at 31.5Hz), and the group delay and waterfall charts are pristine. I wouldn't exactly call it lousy engineering, although from what I've heard I'd probably stick with 15Hz tune and call it a day.
You can see in the results, that sub is optimal in 20 Hz mode. The 15 Hz mode bears out what I'm saying, that extended bass alignments are a bad idea. Just look at the ripple and poor impulse response in 15 Hz mode.

The sealed performance is respectable, but F3 is probably too high for HT enthusiasts who want to feel the explosions.

If this was for music only without a lot of deep bass content sealed is the way to go. For the rest the 20 Hz mode would seem optimal.
 
Swerd

Swerd

Audioholic Spartan
Arguing over ported vs. sealed is missing the point about bass. If the bass cabinet of a ported or sealed woofer is designed properly, they would sound similar. But for nearly all woofers made today, the difference in the dimensions of the sealed and ported cabinets would be large. Because smaller cabinets sell better, most small woofers available today are built to work best in ported cabinets. And, for marketing reasons, most of these ported speakers are actually smaller than the designers would like. The result is they have a noticeable sound where the bass in the roughly 50-100 Hz range is overemphasized. Most speaker buyers are accustomed to hearing this, and many people equate overemphasized bass with good sound.

The real question should be "how much bass over-emphasis do you like?" If you agree with TLS Guy's answer (I do) your answer will be none. Recognizing more realistic limits in space, you could say, "as little as possible". In speaker design & building terms, that would be a total system Q (Qts) of 0.7 or less. When TLS Guy says he aims for a critically damped bass response, he's aiming for a Qts of 0.5. Almost always, this requires large cabinets, bigger than most people want in their homes.

Many of us familiar with frequency response curves should also be familiar what high Qts looks like. If you look at the bass region in the example below, roughly 50-100 Hz, if there is a hump that stands out above the rest of the response, it probably is due to a high Qts.



If done moderately, high Qts can result in acceptable sound for most listeners who mainly play pop music. Unfortunately, a high Qts doesn't just result in over emphasized bass. It also causes the bass to play on an on, like a ringing bell. Depending on the music, this can significantly muddy the lower midrange sound of a speaker, masking a lot of sound detail. Most people are used to hearing this because they haven't heard bass from a critically damped speaker. I've even met people who say they don't like the sound from a critically damped speaker because "it lacks bass slam". Similarly, among some so-called audiophiles, critically damped bass is called "fast bass". This is a misnomer – all bass sound has the same speed – I think they really mean bass that doesn't ring on and on. A single bass note should stop as quickly as it starts.

If a speaker is given a single short impulse of sound, and the bass response is graphed vs. time (in milliseconds), you get an impulse response curve. These impulse curves allow easy comparison between the ringing of a woofer in a low Qts cabinet vs. the same woofer in a high Qts cabinet. As Qts goes up above 0.5, there will be longer and longer ringing of the bass tone. The only way to avoid it is to design a cabinet with a lower Qts.

I once saw in a book or the net, a figure that showed the direct relationship between Qts and bass impulse response of a speaker. I wish I could remember where that was.
 
Steve81

Steve81

Audioholics Five-0
You can see in the results, that sub is optimal in 20 Hz mode. The 15 Hz mode bears out what I'm saying, that extended bass alignments are a bad idea. Just look at the ripple and poor impulse response in 15 Hz mode.
To be honest, I'm not seeing a massive difference in impulse response between the 20Hz and 15Hz modes, although the sealed mode is clearly cleaner. Actually, I'd say the 15Hz mode looks better to my eye than the 20Hz mode. For example, in 20Hz mode in that first set of positive spikes after the original impulse, you can see a spike bumping well above the 40% mark and then going down below -20%. Conversely in 15Hz mode, the spike just nudges above the 40% mark, and doesn't make it back down to -20%.

The sealed performance is respectable, but F3 is probably too high for HT enthusiasts who want to feel the explosions.

If this was for music only without a lot of deep bass content sealed is the way to go. For the rest the 20 Hz mode would seem optimal.
Suffice it to say, I didn't buy the PB13 with the intention of running in sealed mode, especially not for HT, but for what's basically a freebie, it seems to be a quite well executed one.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
The real question should be "how much bass over-emphasis do you like?" If you agree with TLS Guy's answer (I do) your answer will be none. Recognizing more realistic limits in space, you could say, "as little as possible". In speaker design & building terms, that would be a total system Q (Qts) of 0.7 or less. When TLS Guy says he aims for a critically damped bass response, he's aiming for a Qts of 0.5. Almost always, this requires large cabinets, bigger than most people want in their homes.
Yeah, but I think the answer is more complex than this, at least if I understand what you're saying. A system-level Q=0.7 is not the only way to "adjust" bass response. I much prefer a flat response like a Q=0.5 design will give you, but I think an overall, in-room frequency response that tilts up starting at about 100Hz and being about +3db by 20Hz, and is tilted down about 2-3db by 20KHz sounds most natural in a lot of home listening rooms. In other words, small listening rooms. IMO, simply saying the answer is a speaker or an overall system with critical damping isn't sufficient to get "realistic" sound.

Large concert halls generally have pretty consistent bass for any seats away from the walls, but medium-size venues as jazz is often played in have far less even bass response. The music sounds different depending on where you sit; there's no one "right" sound.

Obviously with pop or rock music there often isn't a performance you're reproducing in the classic sense, and I think the Q=0.7 speakers are mostly aimed at this market. Let's face it, it is the majority of the market, and I haven't even mentioned the totally contrived foley of movies.
 
Swerd

Swerd

Audioholic Spartan
Yeah, but I think the answer is more complex than this, at least if I understand what you're saying. A system-level Q=0.7 is not the only way to "adjust" bass response. I much prefer a flat response like a Q=0.5 design will give you, but I think an overall, in-room frequency response that tilts up starting at about 100Hz and being about +3db by 20Hz, and is tilted down about 2-3db by 20KHz sounds most natural in a lot of home listening rooms. In other words, small listening rooms. IMO, simply saying the answer is a speaker or an overall system with critical damping isn't sufficient to get "realistic" sound.

Large concert halls generally have pretty consistent bass for any seats away from the walls, but medium-size venues as jazz is often played in have far less even bass response. The music sounds different depending on where you sit; there's no one "right" sound.

Obviously with pop or rock music there often isn't a performance you're reproducing in the classic sense, and I think the Q=0.7 speakers are mostly aimed at this market. Let's face it, it is the majority of the market, and I haven't even mentioned the totally contrived foley of movies.
You're right :).

I was trying to avoid talking about the added complexities generated by room reflections, which for sound below ~200 Hz in most homes, can have as large an effect as anything else.

It's much easier to tune a speaker's bass performance by adjusting cabinet dimensions to a desired Qts than it is to monkey with a room's bass performance. Too much depends on speaker and listener location not to mention wall, ceiling and floor reflections.

To return to the original post, there's a lot more to it than choosing between sealed or ported cabinets.
 

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