You get an extra octave of low frequency with ported designs, but it’s at the expense of a little coloration, port noise, and I believe also bass tightness and speed, compared to very good infinite baffle designs.
Hsu makes a line of subs you can alter the configuration from ported to sealed. The difference is minimal in measurements. You can find measurements here:
The thing that makes a bigger difference is matching the room. Ported speakers go down deeper and tend to excite those modes more. In this case a speaker with a higher cutoff will often sound better.
Port noise MAY be an issue, but it's usually dealt with by using larger ports and/or using port surfaces which minimize this.
It’s all about the design and materials used. If the designer builds around Infinite baffle, passive radiator, port, or open baffle, the driver has to be tuned to the enclosure, anyway. If you’re lucky, that enclosure has the ability to be tuned to YOUR room. Hopefully without EQing the enclosure(s) to death. That’s the tough one sometimes..
Passive radiators, can tune the box per room, add or subtract mass, to a very fine degree They can correct dampening issues between different power amps via mass addition or subtraction.
Ports are usually fixed, though I’ve seen inserts, and trombone ports. I like trombone bass enclosures too.
I think, "homewreckers" are that way,
Depends on total speaker design and each designer takes a different approach. Wilson, Wilson Benesh and Vivid port. Magico and YG do not.
One thing that is common to Magico and YG is they are both aluminum. Not sure if that has anything to do with it. Could be there is a problem in maintaining damping if you port an aluminum speaker. I haven't worked with that cabinet material and it is pure speculation on my part but it is something to note.
It the port is tuned properly to the driver and enclosures you will find that bass response will be tight and accurate. If placement is wrong or the port(s) are too long or short, cabinet volume is too small for the driver, ultimately you will get poor results.
Room placement is also critical. If the port is too close to the wall, sound gets muddy. With a small bookshelf speaker, I find getting closer than about 18" from the wall leads to a dramatic reduction in clarity. With a 12" sub, proximity to the wall becomes more problematic. Think about how much air flows through the port in a 12" sub vs a standmount with a 6" driver.
Several important points have been made. I'll add just a couple more.
--back in the day when BR designs were poorly tuned, they were touted to "more efficient" because of a peak that was tuned too high. So you gained more "boom" and "efficiency" if you want to call it that. This also gave BR designs of long ago a reputation for inaccurate loose bass-which it was. A properly tuned BR enclosure will extend bass deeper, but as stated above, no gain in efficiency.
--While the BR enclosure will extend bass deeper, it will also roll off faster at 18dB per ocatve below the tuning frequency. A sealed system has a more gentle roll off of 12 db
--Bass response of either system can be great or lousy. It's all about implementation and I don't think one can generalize at all on this issue.
^ If you had ever read any technical papers, you would know the answer to that question, it’s in the literature. Too much trouble to do the work, it’s easier just to display your ignorance and laziness? If you find reading too demanding, can you at least watch videos? Danny Richie has a series of GR Research Tech Talk Tuesday videos on YouTube in which he discusses in detail loudspeaker and subwoofer design.
Ported designs do NOT "go" deeper than do sealed. In fact, the exact opposite is true. Ported woofers provide more output down to resonance than do sealed designs (which are already rolling off at 6dB/octave at their resonant frequency), below which they roll off much faster (12dB/octave) than do sealed. The same driver in a sealed enclosure will play lower in frequency than will the same driver in a ported one, but with lower output above resonance. That's why sealed are recommended for smaller rooms: with the gain provided by that room, a sealed woofer's output will match that of a ported, and will play to a lower frequency. And with, some feel, better sound quality. Rythmik's Peter Ding recommends his sealed models for music reproduction.
The same driver in a sealed enclosure will play lower in frequency than will the same driver in a ported one,
Kind of/sort of. Given the same driver in two ideal cabinets, the ported version will have a lower -3 dB, but since the slope is 4th order (24dB/Octave) instead of 2nd order (12 dB / octave) at even lower frequencies the sealed will catch up. I encourage you to grab a box simulator to prove this to yourself, or look up any woofer in the Madisound woofer list and compare the -3dB points of their recommended cabinets for just about any woofer. Here’s a random example:
As you can see here, the highest -3dB point is achieved with the recommended sealed box.
but with lower output above resonance.
Simply not true. Again, with the same driver in 2 ideal cabinets the ported vs. sealed cabinet has exactly the same output above resonance as the cabinet volume and alignment is no longer involved and is purely a function of the driver motor. This is true for all open back drivers, not just woofers. This is something I actually learned in audio engineering class with Dr. Leach ages ago. I encourage you to read any book on speaker design to further your understanding.
Here my more simple answer, as a lot of the more technical details were shared already.
Closed cabinets tend to sound more 'dry' compared to ported / bass reflex designs.
So bass reflex design will sound LESS dry, by comparison and all this, even when either design is properly implemented.
Also, practically all closed cabinets have to use more stuffing, expensive sheep wool preferred to plastic / hollow fibre to make the bass drivers 'see' more internal volume, where as ported bass reflex cabinets need usualy a far more minimal rip-wool sheeting, layed on all surfaces exposed to the bass drivers.
Since the internal pressure in enclosed cabinets is immensely higher, internal braceing becomes more critical than in an open, bass reflex designs.
To build very large closed cabinets becomes very critical, to impossible.
I suspect, why designers doing this, went for airplane Dur-aluminium material rather than super-wood or wood laminate.
There is plenty more to all this, but this came to my mind on the subject, with out going into issues of Q, vs internal volume etc. etc.
PS: Early Watt/Puppy versions had some problems with their port design (too small in diameter vs required length), producing quite critical bass response issues.
bd24 is right but the result is that the ported design sounds as if it has more bass. Ported designs can be excellent such as Wilson's but the vast majority of them are colored. Designing ports is easy. It is just a math problem. I think where most designs fail is in implementation, cheap materials, resonant enclosures etc.
I do not like any enclosure except for subwoofers. Open baffle speakers crossing over to subs at around 100 Hz work great. I use dipole ESLs
For subwoofers sealed is absolutely best. With signal processing and a very powerful amp you can make the driver do whatever you want. As long as the enclosure is inert you are in business. The best designs now are "balanced force." You put a driver in opposite sides of sealed enclosure so that their vibrational forces cancel out.
Infinite baffle design was mentioned. Bozak used Infinite baffle enclosures. This requires a large enclosure. Large enclosures are difficult to keep quiet. The bigger the board the more prone to vibration and resonance it is. Bozak used 3/4" plywood. The Bozak enclosure was a musical instrument. My father had a pair. With a Dynaco Stereo 70 they played very loud with rich chocolate flavored bass. They were colored as hell but to an 8 year old kid that system was the nuts.
In my own experience except for subs, the best enclosure is no enclosure.
This is a really interesting thread, and because of my technical ignorance I don't have anything factual to add; but my own experience after having owned almost 20 pairs is that while I have enjoyed the sound of a good sealed box speaker, I think that in comparison to a good ported speaker, like the Spendor SP100, or my present Klipsch Epic CF- 4, the bass of the sealed enclosure doesn't "breathe" in the same way. It sounds a little too tight, or maybe a little constipated. The way that the ported enclosure releases the bass notes into decay just seems more realistic to me.
Having said that, I know that there are a lot of poor ported designs; and I've owned a couple that sounded hollow and boomy when they hit certain notes. I would also add that I have not heard the best of the current sealed designs like Magico and YG Acoustcs, so I can't speak for what they sound like.
A lot of c**p being sprayed around here.
Drivers have a huge amount of specs and have preference for one or the other enclosures if built correctly.
To say to plug a port on a ported enclosure and believe the same driver is still in now an ideal sealed enclosure is BS, and then there’s the stuffing that comes into it.
In my first post, Nevile Thiel (rip) has said the correct thing.
Also he said to those that don’t know, to get a the same depth of lows that a ported box has from a sealed enclosure, size is greatly increased, and I’ll add, sealed also tighter/dryer and less colored when done right.
Transmission line is best when properly implemented.Inclined to agree. First speakers I built were transmission lines using the 1980 Speaker Builder Design of Roger Sanders. For drivers I used the 10" woofers from my JBL L25. The bass was obviously, considerably, impressively better than when the same driver was in the ported JBL. More efficient, smoother, deeper. Not even close.
The one advantage the JBL had was size. The L25 is a lot smaller and lighter. That too is a design consideration. But as long as all we care about is sound quality, transmission line all day long.
I have to agree with you George on your point about stuffing ports. How many reviews have all of us read about a ported speaker that was causing room modes or some other issue, and the answer was to plug the ports with bungs? I do know enough to know that a speaker is either designed from the get go to be sealed or ported, and there is a big difference; so how could it be proper to do that?
Transmission line speakers can be really effective. I owned TDL Monitors (twice), and while not obviously "bassy", if there was very low bass on a song like for instance one song on Enya's first disc, it felt like a physical rumble beneath the floor. I think that speaker was rated to have usable response down to 17hz.
I agree that that plugging a port does not make the speaker sound like it is a sealed type. It is an easy extrapolation, which is to be expected in forums, but I find it wrong. Bass "type" is a compromised choice made by builders and not in realm of retail purchasers. While I generally prefer sealed, I: a) do not through the baby out with the bathwater and b) realize implementation quality varies a lot.
An ideal (maximally flat) sealed vs. ported cabinet results in a larger cabinet for the ported speaker, so sealing an ideal ported cabinet should result in a speaker with a higher -3dB point, as well as an earlier roll-off frequency.
Basically, you end up with an over-damped sealed cabinet.
If we are dealing with a sub that you are going to EQ anyway, this is a pretty good direction to try, given how much a room can affect the output.
Putting a woofer into a sealed enclosure raises the resonant frequency of the driver. The acoustic output of the woofer thus starts rolling off at a higher frequency than does the same woofer in a ported enclosure. However, it’s slope is (as Erik properly corrected me on ;-) the shallower 2nd-order, so that as frequency descends, the output of the sealed woofer eventually crosses the more-steeply-falling 4th-order slope of the ported woofer, thereby providing more output at the lowest frequencies both woofers are capable of. I.E., the woofer plays lower in a sealed enclosure than in a ported.
I have a pair of 1/4-wave transmission line enclosures, each with the famous KEF B139 woofer (used in pairs by David Wilson in his WAMM loudspeaker) at it’s front end (together creating a fundamental resonant Q at 15Hz), and while very good for it’s time (early-70’s) is no match for the Rythmik F15HP, let alone the Rythmik/GR Research OB/Dipole Sub. Jim Salk installs a Rythmik subwoofer and associated plate amp in his upmarket speaker models.
I have GRs OB Dual 12", servo. It's different, and takes a bit to get use to. They pressure the room all together different..They can clean a poorly designed room right up. With any treatment at all from 100 hz down..to 20hz< you'll hear and feel every note, with pretty good authority..and great coverage for the Swarm crowd, I heard 4 GRs duals 12s. Yea something to write home about...They are columns, too.. LOL 3 12s
@erik_squires put it very well and very succinctly: "The thing that makes a bigger difference is matching the room."
Lacking Erik’s gift of succinctability, here’s my take, from the perspective of a designer:
In my opinion where the speaker is likely to be placed in the room makes a great deal of difference.
Sealed box design doesn’t offer the designer very many degrees of freedom. Once the woofer and box size have been chosen, the shape of the frequency response curve (not counting room interaction) is virtually carved in stone. Increasing the box size beyond optimum will raise the -3 dB frequency but lower the - 6 dB frequency, while decreasing the box size below optimum will have the inverse effect. And the theoretical "optimum" box size isn’t necessarily optimum for a given application.
Vented box design allows the designer more flexibility but imo requires more care. Assuming the woofer and box size have been chosen, different tuning frequencies result in significantly different frequency response curves. So if I have a pretty good idea of where the speakers will be placed, I can take anticipated boundary reinforcement into account in choosing what the frequency response curve should look like. Also, having multiple pluggable ports allows the end user to somewhat tailor the speaker’s low-end response to his room situation.
Note that the "boominess" often attributed to vented boxes includes the room interaction. Take the same speaker outdoors and it will NOT sound boomy... point being, it is the net in-room frequency response, not the speaker’s inherent low frequency time-domain response, which dominates our perception.
One drawback of ported boxes is this: As a note near the tuning frequency decays, its pitch can actually shift in the direction of the tuning frequency. This makes sealed boxes generally more suitable for small studio monitors than vented boxes; with large studio monitors, the tuning frequency can often be made low enough that pitch-shift is not an issue.
Personally I tend to prefer use ported boxes in my designs for three reasons:
1. Greater room-adaptation flexibility, assuming pluggable ports are part of the design.
2. In general woofers which work well in ported boxes have more powerful magnets and/or lighter cones, both of which imo contribute to midrange articulation.
3. In a series of blind tests intended to sort out the best internal damping material for a sealed box with the priority on midrange sound quality, I accidentally found that a ported box could have better midrange sound quality.
Ever so well said, a knowledgeable designer speaking.
Totally agree on all said, given my comparative limited experience, though having been involved in speaker building and related theory some ten years ago.
Theory wouldn't have much, if at all, changed. I suspect implementation however would have, yes? 🤔
Here are the T&S parameters needed for the ideal ported enclosure, if you think you can just throw a sock in the port and have a sealed (IB) enclosure to suit the same driver, your nutz.
But to me if "big enough" with driver "that suits" an IB box, then you have a "better lower tighter bass"
Nevile Thiel (rip) helped me make two huge 12cu.ft ported enclosures (about the size of two large fridges) for two very rare massive Kef B1814 (flat diaphragm pis-tonic motion) f/s 20hz drivers I had.
These bass units got used from 100hz-18hz flat. While serving me very well with Accustat 2+2’s as mains, those huge bass bins were shamed a few years later by the majestic ACI SV12 f/s 17hz drivers in sealed IB enclosures 100-20hz, the speed and the concussion into the kidney region couldn’t be match by those ported boxes .
Transmission line enclosures are darn hard to design. Roger Sanders makes the best one I've ever heard.
I personally do not like deep base coming from my satellites. But, I use ESLs and cross to sealed subs at 125 Hz.
I am not sure about this but I do believe it is harder to make a ported design operate below it's resonance frequency than a sealed design.
This might allow the sealed design to work better with room control. I have not used room control that way. I would always use subwoofers which might make the seal/port argument mute.
Sooo much mis information posted in this thread. Ported or sealed enclosure should be based on the individual driver(woofer) and its requirements. If anyone wants to look at driver spec's here are a few guidelines that will help you understand.
I will describe 3 of these in elementary terms that are fairly accurate for easy understanding.
1st Ported qualify's as vented, bass reflex, transmission line etc.
FS.... a drivers low end resonance (how low it can go) hanging in free air. In a few cases a driver can go below its resonance, but it is rare.
QTS..... this spec gives you a good idea of what a woofer will need for type of box...... A low QTS requires a ported box to play any real bass, Mid level QTS can go both ways, but will typically still go lower in a ported box. Higher QTS typically likes a sealed box, they can port out, but would need a large box and can be boomy.
VAS..... Gives an idea of how much back pressure or volume of air a box must create on a woofer to produce bass, in combination with QTS, we know how big a box needs to be for a given woofer.
Every woofer has these parameters, plus many others that are relevant in producing satisfying bass. A QTS of .2 even with a low fs will sound more like a mid range in a sealed box, it must be ported to go down at all, a QTS of .35 will still not go down in a sealed box, but can produce very satisfying bass when properly ported. A QTS of .4 to .45, I typically still like to port, but we are getting into territory where a woofer can go down in a sealed box. A QTS of .5 to .55 is ideal for a sealed box.... when you get above .6 or so, a driver can get boomy or harder to get the finished Q inside the box (QTC) to a respectable area.
Another Fact that is easy to bend...... ANY WOOFER IN ITS PERFECT SEALED BOX WILL AWAYS REQUIRE A LARGER BOX FOR ITS PERFECT PORTED BOX. The glory of ports is that they are very flexible in design and even though that bold statement is true, you can get satisfying results from a ported speaker in a smaller box.
Guys, none of this is Opinion. You either design a box and scour the earth for a woofer that will work in it, or you design a speaker and build the box that it needs for optimum performance....
I hope this all helps, Tim
Generally, sealed box enclosures, there are at least 3 types, have flatter base response curves than ported enclosures, but are less efficient. Some ported enclosures have passive reverberators covering their ports to enhance efficiency, base content and flatness of response. There are great examples of all designs, and there are some not so good examples. It all comes down to what sounds good to you in your listening space.
I build high end speakers for a Utah based company. My company has utilized both designs with great success. I have spent years and years of listening to both. There’s just some thing about a well designed sealed speaker that sounds so good to my ear. Tight, quick. Not as efficient as ported, but feed it enough power and kaboom.
I built a pair of speakers we never offered the public. It was a studio monitor with a very heavy cast frame 12” aluminum woofer, a 6.5” mid and Vifa tweeter. Man did it have an amazing low end response.
I also dont consider any speaker with a port or a transmission line. I am aware of the basic pros and cons of each design and tend to rely upon my experience listing to each type. The best bass I have ever heard always has come from a sealed enclosure. I believe the issue is more intrinsic than engineering and design.