Ported vs. Unported speakers

[Keith_W]

Alan Langford (from DEQX, at the SNA show): "no speakers should have ports! Ports create more issues than they solve. You get different problems with unported speakers, but they are less position dependent and you can solve those issues with subwoofers or with DSP". Another attendee: "but 80% of speakers have ports". Alan: "that's why 80% of speakers are awful". 

 

I agree with him. I don't like ported speakers myself, for the same reasons. 

 

Discuss. 

Edited November 2, 2023 by Keith_W

[Neo]

40 minutes ago, Keith_W said:

Discuss

You mean argue. 
There are plenty of different designs for different budgets and the end user decides what’s superior in their setup needs. Generalizing comments lead nowhere.

Neo

[playdough]

One could surmise, ported enclosures can require less EQ so in essence a less complex system as in electronics, which some Hobbyists prefer, particularly in an entirely analogue set up.

There is also an efficiency gain, so lower power systems can benefit.

Interesting topic although a little biased toward sealed enclosures.  

photo is of actual testing of a ported enclosure (a pair of 21's), showing what the port  achieves in the real, to support my statement. Could have built a sealed enclosure however it might sound a little thin on bass before some EQ intervention., which with a smaller power amp or simple system, may not be possible.

Confirmation bias at best. 

 

Edited October 27, 2023 by playdough

[Cloth Ears]

52 minutes ago, Neo said:

You mean argue. 
There are plenty of different designs for different budgets and the end user decides what’s superior in their setup needs. Generalizing comments lead nowhere.

Neo

Essentially, there's badly designed ported boxes and badly designed sealed boxes, as well as badly designed open baffle or baffle-less speakers. DEQX will be able to fix all but the badly designed ported speakers, so naturally Alan is against them...

[Satanica]

2 hours ago, Keith_W said:

Alan Langford (from DEQX, at the SNA show): "no speakers should have ports! Ports create more issues than they solve. You get different problems with unported speakers, but they are less position dependent and you can solve those issues with subwoofers or with DSP". Another attendee: "but 80% of speakers have ports". Alan: "that's why 80% of speakers are awful". 

 

I agree with him. I don't like ported speakers myself, for the same reasons. 

 

Discuss. 

 

Can you and @artaudio please tell us why well designed ported speakers are "awful"?

[Hi-Fi Whipped]

I compared ported floor standers with larger non-ported speakers from the same speaker brand and range and chose the smaller ported speakers.

 

The main differences I found:

- Larger sound stage

- Tuneful bass without DSP or tone controls by tweaking the speaker distances from the back wall and corners.

- Deeper 3D sound stage, which I put down to the fact that the rear port was flooding the wall with sound in a different depth to the tweeter (but I could be wrong). It sounded like some of the sound was coming from a couple of metres behind the wall the speakers were in front of.

 

I am using sealed speakers now and haven't heard that 3D sound stage depth at all. It may just be the speakers I'm using??

[vinilink]

Also, there are rear and front ported speakers to choose from depending on how to and where you want to place them. Not saying ported are better even though my standmount are ported. 

[RoHo]

It's very difficult to produce a sealed speaker that produces low bass that doesn't look like a veneered fridge with family-pizza sized woofer   Yes you can add subs and DSP for a smaller main speaker but this is more complex and costly.  Compared to your average small-ish, inexpensive ported 2-way floor-stander that will go down to 40-50Hz.  That's why 80% of speakers are ported.   The trick there is to design the enclosure and port so that the bass response is not all woofy and wonky, so the designer needs to be experienced and competent.    

Looking at it from the DEQX angle - it's gonna have DSP so a simple sealed box with that can deal with a lot of power is the shortest way to a good outcome.

 

Edited October 27, 2023 by RoHo

[Keith_W]

3 hours ago, Satanica said:

 

Can you and @artaudio please tell us why well designed ported speakers are "awful"?

 

As you know, ports need to be tuned for the enclosure and desired frequency. The disadvantages: 

 

1. If the drivers are not isolated from each other, midrange and upper frequencies go through the port as well, producing coloration. 

2. The output of the port is slightly delayed and out of phase with the driver output. 

3. More group delay and worse transient response in ported speakers, 

4. Total loss of dampening on the driver below the port's tuning frequency resulting in a massive rise in distortion, 

5. Dampening of lower frequencies depends on the driver's suspension and back EMF, so drivers need to be chosen carefully otherwise they may fail. This may also increase demand from the amplifier. 

6. Ported speakers are more sensitive to temperature and humidity, because the speed of sound varies with both and affects port tuning, 

7. If the port is not properly designed you may get bass resonance, or "one note bass", and you may also get chuffing, 

8. More complex to design and a more rigid cabinet is required, which somewhat negates the lower cost advantage. You save some money on the drivers but you spend it on the cabinet. 

9. Wasn't there a thread on SNA not too long ago about wasps crawling into the port and making a hive there? 

 

The advantages are: lower cost, more sensitivity, a little bit louder, more gentle roll-off slope for bass. I think it is easier to overcome those issues than to deal with all the acoustic issues caused by ports. If you have the misfortune of buying a poorly designed loudspeaker, there is no way to deal with those issues, nothing will fix it, not even DSP ... except stuffing the port and converting it to a sealed speaker. If I visit someone and they complain about bass issues, the first thing I do is stuff the port and see if that fixes the problem. 

 

These days, poorly designed ported speakers are far less common because more designers are using speaker design software which negates many of the disadvantages, but for me I would rather not have to deal with a port. 

[Satanica]

32 minutes ago, Keith_W said:

 

As you know, ports need to be tuned for the enclosure and desired frequency. The disadvantages: 

 

1. If the drivers are not isolated from each other, midrange and upper frequencies go through the port as well, producing coloration. 

2. The output of the port is slightly delayed and out of phase with the driver output. 

3. More group delay and worse transient response in ported speakers, 

4. Total loss of dampening on the driver below the port's tuning frequency resulting in a massive rise in distortion, 

5. Dampening of lower frequencies depends on the driver's suspension and back EMF, so drivers need to be chosen carefully otherwise they may fail. This may also increase demand from the amplifier. 

6. Ported speakers are more sensitive to temperature and humidity, because the speed of sound varies with both and affects port tuning, 

7. If the port is not properly designed you may get bass resonance, or "one note bass", and you may also get chuffing, 

8. More complex to design and a more rigid cabinet is required, which somewhat negates the lower cost advantage. You save some money on the drivers but you spend it on the cabinet. 

9. Wasn't there a thread on SNA not too long ago about wasps crawling into the port and making a hive there? 

 

The advantages are: lower cost, more sensitivity, a little bit louder, more gentle roll-off slope for bass. I think it is easier to overcome those issues than to deal with all the acoustic issues caused by ports. If you have the misfortune of buying a poorly designed loudspeaker, there is no way to deal with those issues, nothing will fix it, not even DSP ... except stuffing the port and converting it to a sealed speaker. If I visit someone and they complain about bass issues, the first thing I do is stuff the port and see if that fixes the problem. 

 

These days, poorly designed ported speakers are far less common because more designers are using speaker design software which negates many of the disadvantages, but for me I would rather not have to deal with a port. 

 

A fair few ifs there. My question was around well designed ported speakers, so all of the ifs are not a factor. Can you point to any measurements that clearly show negatives\deficiencies? I've seen these in a particular subwoofer which was measured in sealed vs two different ported versions.

 

Regarding advantages, it's my understanding that a ported speakers can be made a lot louder in the bass than a sealed speakers in the same enclosure. Not just "a little louder" and the roll off will actually generally be less gentle. Distortion in bass frequencies will generally be magnitudes higher in a sealed speaker than a ported one for the same output.

IMO stuffing a speaker port, in general, is a bad piece of advice because you've just changed the designer's design and become an amateur speaker designer. The only way stuffing a port makes sense, is if you're going to add subwoofers and apply a high and low pass filter and one that is pretty high e.g 80Hz but I'm just generalising here.

 

I think saying "all ported speakers are awful" is just exaggerating and unwise and this comes from someone who has four speakers in my setup and they are all sealed.

[metal beat]

7 hours ago, Keith_W said:

Alan Langford (from DEQX, at the SNA show): "no speakers should have ports! Ports create more issues than they solve. You get different problems with unported speakers, but they are less position dependent and you can solve those issues with subwoofers or with DSP". Another attendee: "but 80% of speakers have ports". Alan: "that's why 80% of speakers are awful". 

 

I agree with him. I don't like ported speakers myself, for the same reasons. 

 

Discuss. 

 

Keith

 

Do you mean sealed speakers or all non ported speakers are better?

  Like electrostatic speakers, dipole speakers,  open baffle speakers  etc.

 

 That is a pretty big brush you are using.

[playdough]

24 minutes ago, Satanica said:

a lot louder

True, in the post measurement above roughly 7 dB at 30Hz. which is a lot louder almost 4 times louder.

It's a lot of acoustic/power amp and EQ. Orders of magnitude and if someone wants to just run a lovely old low wattage valve amp (rather than the alternative), a good tuned (with love, care and attention)  enclosure is a game changer.

This is old rope.

 

[Al.M]

I’m ok with ported speakers, if one has to augment a speaker with a subwoofer doesn’t that mean there is a shortcoming in one design vs another?

 

At the low end of budget spending ported speakers are much more full range sounding.

[Keith_W]

1 hour ago, Satanica said:

 

A fair few ifs there. My question was around well designed ported speakers, so all of the ifs are not a factor. Can you point to any measurements that clearly show negatives\deficiencies? I've seen these in a particular subwoofer which was measured in sealed vs two different ported versions.

 

Not offhand, I would have to do a search. 

 

1 hour ago, Satanica said:

IMO stuffing a speaker port, in general, is a bad piece of advice because you've just changed the designer's design and become an amateur speaker designer. The only way stuffing a port makes sense, is if you're going to add subwoofers and apply a high and low pass filter and one that is pretty high e.g 80Hz but I'm just generalising here.

 

Stuffing a port with an old shirt is easily reversible. It's not as if you are making major changes that can not be undone. If the result sounds or measures worse, just pull the shirt out. There is no problem there. 

 

1 hour ago, Satanica said:

I think saying "all ported speakers are awful" is just exaggerating and unwise and this comes from someone who has four speakers in my setup and they are all sealed.

 

I think it's a crutch for designers. They can design speakers that go louder without a port, so why use a port? There is no escaping the fact that the output of the port is out of phase with the driver, and there is no way to design around it without increasing group delay. You can't even fix it with DSP. It is true that higher sensitivity is of benefit to some folk, but then you are compromising a speaker to cater for a compromised amplifier. 

 

1 hour ago, metal beat said:

Do you mean sealed speakers or all non ported speakers are better?

  Like electrostatic speakers, dipole speakers,  open baffle speakers  etc.

 

 That is a pretty big brush you are using.

 

I am obviously talking about boxed speakers and not ESL's, dipoles, and so on. Those have different issues and should be discussed separately. 

 

41 minutes ago, Al.M said:

I’m ok with ported speakers, if one has to augment a speaker with a subwoofer doesn’t that mean there is a shortcoming in one design vs another?

 

Yes, quite often sealed speakers need subwoofers. But I happen to think that most systems benefit from a subwoofer anyway. I also think that the flexibility of placing your subwoofer where it is most advantageous for bass is better than having your bass coming from your main speaker. You get to place your main speaker where it is best for creating a stereo image. This may or may not be the best position for bass. 

 

I get it - some people want simplicity, fewer boxes in the room, higher sensitivity for small amps, bigger sound from smaller speakers because of other limitations (such as WAF, small space), they have smaller budgets, and so on. And yes, it is possible to design around the port and produce an excellent result. The recent SNA show was proof of that. So yes, perhaps my statement was a bit provocative. 

[Satanica]

35 minutes ago, Keith_W said:

I think it's a crutch for designers. They can design speakers that go louder without a port, so why use a port? There is no escaping the fact that the output of the port is out of phase with the driver, and there is no way to design around it without increasing group delay. You can't even fix it with DSP. It is true that higher sensitivity is of benefit to some folk, but then you are compromising a speaker to cater for a compromised amplifier.

 

Like practically everything in audio, it usually comes down to audibility threshold level.

Well, I say this is what it should come down to.

So you have phase shift introduced with a port and it's easy to say, phase shift bad, don't do it, but that's meaningless without knowing the level of threshold where is becomes audible in any given speaker and at what frequency.

 

And surely more importantly, frequency response and phase are tied together, so it's really only the adverse effect a phase shift has on frequency response that matters, especially at low frequencies. It's what comes out of the drivers and the port and how they sum together is what dictates the level of "sound quality".

 

I just looked at thread on ASR, where an experiment was done using the same woofer in the same box where one box was sealed and other ported.

When they were EQ'd to virtually the same frequency response then the phase was virtually identical.

Edited October 27, 2023 by Satanica

[murrmax]

Quote

bass response is not all woofy and wonky

any low bass at volume from a 6.5inch ported speaker will be woofy and wonky, and farty...until it buzzes and dies - if a designer chooses to get lower bass out of a 6.5 driver power handling will suffer, distortion will be high, and the driver will go woofy and wonky.. 

 

Quote

Distortion in bass frequencies will generally be magnitudes higher in a sealed speaker than a ported one for the same output.

No - the opposite, a driver is better controlled in a sealed volume - it will just not reach the same frequencies 

 

 

Sealed is great if you have proper sized drivers e.g 15,18 inch bass, an active setup with dsp and powerful amplification. 

 

So yes in theory no speakers should have ports, or passive crossovers tbh.. In an ideal world sealed is preferable with a multidriver active system with DSP sealed subs and or decent sized drivers, however ported are a acceptable compromise when you have constraints such as box size, driver size and number, amplifier power, cost constraints it's easy to see why they exist..  

 

[andyr]

Agree with you, @murrmax.

 

 

The only reason I can see for having a port ... is to extend the depth of the bass response.

 

However, as you say - the resulting bass is less controlled than that from a sealed box.

 

 

 

[LogicprObe]

 

I have speakers with ports and speakers without them.

 

I prefer them without.

[playdough]

A question post statement  to the learned of the Forum, sorry if it seems a little left of field, but having problems with almost too many statements to comment on ! 

 

A woofer in a 0.707 sealed enclosure, with EQ  provides  a frequency response of 40 to 100Hz +/- 3dB producing 96dB at say 150w at an excursion max of 25mm. (+12dB EQ @40Hz required for FR) 

 

The same driver used in a ported enclosure tuned to deliver +/-3dB FR of 40 to 100Hz  producing 96dB at 15w at an excursion max of 10mm (no EQ)

 

Driver has an X Max of 25mm.

 

We will ignore for a moment the port is silent in operation and the phase shift at port/cone transition, really is irrelevant and not audible 

 

A fairly realistic experiment ? Please advise if not.

 

Which enclosure type will show more measured distortion ? and what will the phase plot be for both units, similar or not ? 

 

I'm not a ported enclosure biased Audiophile, regarding all speakers as potentially fine, in application. Just a question.

( I may already know the answer to.)

Edited October 27, 2023 by playdough

[stereo coffee]

21 minutes ago, andyr said:

Agree with you, @murrmax.

 

 

The only reason I can see for having a port ... is to extend the depth of the bass response.

 

However, as you say - the resulting bass is less controlled than that from a sealed box.

 

 

 

It is worthwhile experimenting with port length in bass reflex systems. Which is not to say the loudspeaker manufacturer did not design their loudspeaker appropriately.  ( a regular cry when this is mentioned )  More so, extending the port away from the speaker can help to discover the actual capability of bass reflex systems,  where you listen to it. A simple basically zero cost experiment using a kitchen wrap roll can help to establish the concept.  

 

Non ported speakers , where the internal air is made to be a spring is a 69 year old invention, of this clever person, and is well worthwhile understanding, to reduce cabinet volume and extend bass response  https://en.wikipedia.org/wiki/Edgar_Villchur

[andyr]

9 hours ago, stereo coffee said:

... is a 69 year old invention, of this clever person, and is well worthwhile understanding, to reduce cabinet volume and extend bass response  https://en.wikipedia.org/wiki/Edgar_Villchur

 

Yes, it certainly does that, Chris.

 

But IMO - there is never a 'free' lunch - so the penalty you pay for the above (highlighted in red) is ... less tight bass than you would've got from the larger sealed cabinet.

 

[stereo coffee]

1 hour ago, andyr said:

 

Yes, it certainly does that, Chris.

 

But IMO - there is never a 'free' lunch - so the penalty you pay for the above (highlighted in red) is ... less tight bass than you would've got from the larger sealed cabinet.

 

You must have some how missed out,  hearing a pair , the designers effort is described here , per the earlier link

 

Villchur's speaker systems provided improved bass response while reducing the speaker's cabinet size. "He came up with the idea for a new form of audio loudspeaker, one that would greatly reduce distortion by replacing the nonlinear mechanical spring with a linear air cushion. This "acoustic suspension" design demonstrated a greater undistorted SPL (sound pressure level) at 25 Hz than any previous loudspeaker type, including bass reflex, infinite baffle, or large horn designs. Villchur's new and sophisticated understanding of the inexorable relationship among low-frequency extension, efficiency, and cabinet volume was later termed, by Henry Kloss, "Hofmann's Iron Law".

 

[davewantsmoore]

On 27/10/2023 at 8:31 AM, Keith_W said:

Alan Langford (from DEQX, at the SNA show): "no speakers should have ports! Ports create more issues than they solve."

Agreed.

 

... but, there are ports and there are ports.   Most ports end up being quite non-linear in one way or another.... and other times they're just a necessary evil for the design you want to achieve.

 

"Ports" can be used to linearise the response of the driver, but they don't usually radiate much sound.  Sometimes this is called an "aperiodic enclosure" ... but really it's just attempting to optimise the air load behind the driver.

 

One of the main reasons why ports have stayed around forever, is that the EQ required to correct a sealed box woofer to a flat response to the lowest frequencies you might want to operate it at, can be impractical to do with a passive crossover/EQ network.    That being said, you still routinely see this stuffed up in active speaker designs also (wrong driver correction on a sealed box woofer).

 

19 hours ago, Keith_W said:

3. More group delay and worse transient response in ported speakers, 

Not (so much) f they are corrected to the same frequency response.

This is really a "general myth".... which can be true in practise (ie. sealed and ported speaker typically don't have the same LF frequency response) .... but obscures peoples understanding of what is really happening --- ie. it's the difference in frequency response more than anything that is responsible for the error.  ie. if you EQ your sealed box to the response of a ported box.... then the "transient response" (lol) will be the same as a ported box.

 

14 hours ago, murrmax said:

No - the opposite, a driver is better controlled in a sealed volume - it will just not reach the same frequencies 

 

By saying "sealed distortion would be worse" the assumption is that the same SPL and frequencies were employed.... meaning the sealed driver needs to move more.

 

I expect the assumption was also that we are using the driver close-ish to it's limits (where distortion goes up).

 

Obviously if we're not using drivers anywhere near where distortion becomes significant, or giving it a holiday on reaching the same SPL or Hz than the ported box... then things change.

 

12 hours ago, playdough said:

A question post statement  to the learned of the Forum, sorry if it seems a little left of field, but having problems with almost too many statements to comment on ! 

 

A woofer in a 0.707 sealed enclosure, with EQ  provides  a frequency response of 40 to 100Hz +/- 3dB producing 96dB at say 150w at an excursion max of 25mm. (+12dB EQ @40Hz required for FR) 

 

The same driver used in a ported enclosure tuned to deliver +/-3dB FR of 40 to 100Hz  producing 96dB at 15w at an excursion max of 10mm (no EQ)

 

Driver has an X Max of 25mm.

 

We will ignore for a moment the port is silent in operation and the phase shift at port/cone transition, really is irrelevant and not audible 

 

 

12 hours ago, playdough said:

A fairly realistic experiment ? Please advise if not.

It is... but if you are talking about your own woofer, then I don't think it is free from phase shift ; ) ..... but.

 

Using a simple piston formula...a. driver which makes 93dB (@1m) from 25mm excursion ..... will be ~3.5 inches in size.    So the numbers in the example are a long way off.

 

12 hours ago, playdough said:

Which enclosure type will show more measured distortion ? and what will the phase plot be for both units, similar or not ? 

In general, if the frequency responses are calibrated to the same

 (all the way to very low frequencies), and the port is not of some silly design.... then the phase plot is similar.

This isn't typically done though, and so the ported driver will have more phase shift due to it having a 24dB/octave high pass response, rather than the 12dB/octave response of the sealed box.

 

The most distortion will depend on the design of the port.   The ported box will probably have less distortion in certain frequency and SPL ranges .... but either could be designed to have insignificant distortion.

 

 

[Grimmie]

12 hours ago, stereo coffee said:

It is worthwhile experimenting with port length in bass reflex systems. Which is not to say the loudspeaker manufacturer did not design their loudspeaker appropriately.  ( a regular cry when this is mentioned )  More so, extending the port away from the speaker can help to discover the actual capability of bass reflex systems,  where you listen to it. A simple basically zero cost experiment using a kitchen wrap roll can help to establish the concept.  

 

Non ported speakers , where the internal air is made to be a spring is a 69 year old invention, of this clever person, and is well worthwhile understanding, to reduce cabinet volume and extend bass response  https://en.wikipedia.org/wiki/Edgar_Villchur

 

Thanks for the link Chris, very interesting reading and what an important figure in our hobby. Love this title from one of his articles; Villchur, E. (1964) "High Fidelity Measurements - Science Or Chaos?" Electronics World, August 1964. Apt then and certainly now.

 

My speakers are sealed (SGR 3.2) 2 X 10" bass drivers, they have no problem producing very deep, super contrlled bass, I do not have a need for sub-woofer augmentation.

[davewantsmoore]

2 hours ago, andyr said:

But IMO - there is never a 'free' lunch - so the penalty you pay for the above (highlighted in red) is ... less tight bass than you would've got from the larger sealed cabinet.

 

This is really one of those myths which cause no end of confusion to people trying to understand how speakers really work.

 

If you were to EQ the ported box and sealed box to the same frequency response.... and use them both at SPLs where there was no severe non-linearities occurring .... then they both have a very close to identical response... and there is no difference in "tight bass".

 

Said another way, 99% of the difference between them is simply their inherently different frequency response...... but most people do not do any sort of calibration or apples-to-apples testing this.    This is often very understandable.... as they just want to compare the "uncalibrated response" of various speakers you get at the hifi shop, or whatever.... but as mentioned, the generalisation creates a complete brain hijack for anyone attempting to understand what causes what about speakers and their design.

 

52 minutes ago, stereo coffee said:

Kloss, "Hofmann's Iron Law".

Once we understand this law.... then it becomes a bit silly to claim acoustic suspension as the "most superior" .... or any cabinet type really, as the law tells us how to optimise the system to get what we want.    Any low frequency cabinet type can be good, for a certain purpose.... horses for courses.   Any cabinet type can sound "the best", if you want to optimise for that, and design it carefully.  <shrug>