Sealed speakers VS ported

[Michou]

Proac Tablette 10.

KLH Model 3 and 5
ATC (Some)
NHT
Magico
Human Speakers
Audionote (Some)
Gershman Acoustics
Klipsch Heresy
Buchardt Audio S400 (ABR)
Role Audio
NSMT Loudspeakers

 

[voodooless]

I’ll post some examples later of reflex and closed systems eq’er to roughly the same response. You’ll see that the group delay will be equal as well.

So, here is goes. As an example the SB15CAC, closed and BR. Here the frequency response of both (green BR, blue closed):

And the group delay:

Now lets EQ the closed one very close to the BR version:

Close enough...

Now what does the group delay look like:

Well, well, closed does "worse", even though they look the same. Why? because the closed version has a tiny bit steeper downward trend. If you were to EQ that exactly the same, they would be the same as well.

But I would not bother. The room has so much influence on the response, that these tiny differences are irrelevant anyway. So the main goal should be to create a flat in-room response, regardless of the type of alignment you have. This will always yield the best group delay.

 

[dasdoing]

@voodooless

ok, we can say that aritificialy boosting up the closed response roll-off causes the same damage......still the group delay explains why the ported speaker has a "too slow" feel to it.
better let it roll than let it groal I guess

 

[Speaker_tweaker]

I agree with voodooless, because the room exerts such a strong influence on the bass, it is very hard to attribute something you are hearing to the speaker itself.

I am also under the impression there are a fair number of ported speakers that have design issues, especially in PA and DIY. Ported speakers are just harder to design and are more sensitive to certain issues like box leakage. Whereas with a sealed speaker you can take a cheap woofer that performs terribly in a vented design and get a good result in a sealed box.

I haven't seen convincing evidence that a well-designed ported speaker can't sound as good as a sealed speaker.

See the article "getting the bass right" here https://www.harman.com/audio-innovations

 

[Frgirard]

the audibility of the group delay...

 

[Mackie]

Not sure how applicable this video on sealed vs ported subs is but I enjoyed it

 

[tuga]

Sealed enclosures are said to reproduce transients more accurately...

 

[thewas]

Sealed enclosures are said to reproduce transients more accurately...

This is of course true as the port is a resonator and as such needs some extra time/oscillations to rise and fall in amplitude, the question is how much and what is audible.

As an anecdotal personal experience if I have the choice I usually end up closing the ports of subwoofers as it mostly sounds better to me when equalised to the same LP response but my experience is as said anecdotal, not blinded and limited.

 

[tw 2022]

Does anyone know who makes a good sealed standmount nowadays ?

Nht ..c3 or c1....speakerlab does sealed designs as well, but haven't been measured afaik...the speakerlab point 1+ sounded good to me, but it's tiny, it would be good in a small room..

 

[Chrispy]

Curious, @Mackie just what speakers are you using or is this experience based on?

Then there are acoustic suspension type sealed vs merely sealed as far as what might have better bass in a speaker too .

 

[jhaider]

the better integration with a sealed speaker is a non sens.

Not really, unfortunately. The reason is “THX” bass management has unaccountably stuck around even though the speakers designed to go with it have not. So with most AVR/P’s you will get better theoretical integration with something like an NHT C3 or Revel Gem2 than with a typical vented speaker.

 

[dfuller]

Whereas with a sealed speaker you can take a cheap woofer that performs terribly in a vented design and get a good result in a sealed box.

I'm not sure that's strictly true. Sealed boxes need different requirements than a vented design. Namely, more linear excursion.

 

[Mackie]

Curious, @Mackie just what speakers are you using or is this experience based on?

Then there are acoustic suspension type sealed vs merely sealed as far as what might have better bass in a speaker too .

At the moment using a pair of older sealed Ruark Sabres MK2.
Also heard some old vintage AR sealed speakers (forget the model) recently and they had the same kind of fast textured bass quality as the sabres. Also some sound-artist LS3/50A.
For comparison, Ported speakers I've recently listened to are some Audio-notes (loved these), vandersteens (nice), Monitor audio Silvers, Adam Monitors. dynaaudio monitors.

 

[Chrispy]

At the moment using a pair of older sealed Ruark Sabres MK2.
Also heard some old vintage AR sealed speakers (forget the model) recently and they had the same kind of fast textured bass quality as the sabres. Also some sound-artist LS3/50A.
For comparison, Ported speakers I've recently listened to are some Audio-notes (loved these), vandersteens (nice), Monitor audio Silvers, Adam Monitors. dynaaudio monitors.

Are they like the old AR and of an acoustic suspension type (as described in this article )?

 

[Mackie]

Are they like the old AR and of an acoustic suspension type (as described in this article )?

Yes, bass was wonderful to my ears on these.

 

[gene_stl]

Back in the day there was a term for bass reflex exciting room modes. It was called "Bass Overhang" Ported enclosures try to utilize the acoustic energy in the rearward going wave after delaying it through a series of resonators and attenuators. (the box and the baffles , stuffing and port, and any passiver radiators that might be used.) This causes wild gyrations in the response and group delay.

I don't know whether it is or would be audible in a proper blind test. It also does depend on the net response of the system and the room.

But in the really ancient days of tube amps they were trying to get the system sensitivity up because all they had were little tube amps. When they started wanting to have more accuracy after tube amps got big and when transistor amps started appearing (late fifties and early seventies) the acoustic suspension appeared. Popularized by Acoustic Research , Bozak and others. JBL and Altec Lansing and WE had been the champions of efficiency because they were catering to the cinema users. After the appearance of AR and their clones JBL came out with the Linear Efficiency series of drivers which had longer voice coils and were intended for use in either sealed boxes or with passive radiators which were supposed to cure some of the ills of ported enclosures. Pasiive radiators from JBL came with sets of weight discs to help adjust the response. You could add or subtract weight discs to adjust Passive radiators moving mass and response curve.

It got as far as being described as "the west coast sound" , supposedly better for rock and roll with boomier bass. versus the east coast or Boston sound and by extention later the British sound. which was supposed to be better for classical music and more "reserved" and accurate.

I have had both types of systems. I listen mainly to classical music and have always preferred the sound of sealed enclosures. I don't know how much of that is expectation bias.
Having had a system where it is very easy to make lots of adjustments to crossover frequency , slope and shelving , I take a very dim few of audibility as a test of merit for the most part. On the other hand if you have multiple experiences and always prefer one type that is a potentially valid data point. Furthermore if you like the sound of a particular speaker , whether it agrees with measurements , or not or whether you could or couldn't pass a blind test, don't matter. If you like it that is what you should use.

My favorite anecdote along these lines which did not require any test blinding was taking my long suffering and very patient wife to see the movie "Midway" (before we were married and in spite of my speakers she married me anyway saying "Love me , love my speakers!") The early Sensurround system was just a "gating" track on the film.
When there was an explosion they gated the bass channel "ON" for a period of time appropriate to the explosion. But it could only make one note! By the third triggering I had figured that out, and I got angrier and angrier as the film progressed (it was otherwise a great film about an epic battle). The subwoofer system was a large number of drivers in a sort of bi directional horn arrayed across the front floor of the room under the screen. The theater was a relatively smaller rectangular room. There was only one note. I think it was in the 15 Hz range. It sounded TERRIBLE. The speakers and boxes in the Sensurround system were from Cerwin Vega whose speakers were loved by guys that wanted rock out LOUD. The amps were often BGWs a pioneer of big solid state amps (with a fast slew rate)

Sensurround - Wikipedia

en.wikipedia.org

Cerwin-Vega - Wikipedia

en.wikipedia.org

BGW Systems - Wikipedia

en.wikipedia.org

 

[gnarly]

So, here is goes. As an example the SB15CAC, closed and BR. Here the frequency response of both (green BR, blue closed):
View attachment 236624
And the group delay:
View attachment 236625

Now lets EQ the closed one very close to the BR version:
View attachment 236626
Close enough...

Now what does the group delay look like:
View attachment 236627
Well, well, closed does "worse", even though they look the same. Why? because the closed version has a tiny bit steeper downward trend. If you were to EQ that exactly the same, they would be the same as well.

But I would not bother. The room has so much influence on the response, that these tiny differences are irrelevant anyway. So the main goal should be to create a flat in-room response, regardless of the type of alignment you have. This will always yield the best group delay.

Yep. Nice presentation/explanation.

Simple physics is that group delay is a function of phase, which is a function of frequency response (in a minimum phase speaker).
So like you say, with the exact same response, sealed and ported will be the same....measuring...and sounding.

However, I think all the impressions people have about the sound differences between sealed and ported are generally correct.
But they are correct because they were never really able to get to a true apples-to-apples comparison.

I'll use my own experiments and DIY subs as an example of what i think it takes to get to apples to apples.
I put the same 18" BMS 18n862 driver in sealed and ported boxes, designed with Hornresp, and then measured and tuned via transfer functions.
Measurement and tuning was done ground-plane outdoors, free of room.

The ported box of course had lower response (as per you nice demonstration voodooless).
When I matched the sealed frequency response to that of the ported using a Linkwitz transform ala miniDSP, phase and group delay became the same too.
And so did the sound.
Outdoor matching is really the only fair way to be able to evaluate their sound...either outdoors or when taken back indooors, imho.



Now, all that said....I do think sealed is the best way to go ....for the smoothest rolloff down low and less phase rotation /group delay for better transients.

But the way to use sealed for lower extension is NOT with low end EQ boost (link a Linkwitz transform, shelving or para EQ's. They just add back the group delay and undo the whole purpose of sealed.

The way to use sealed for lower extension is simply get bigger drivers, or more drivers.
Displacement rules !!!!

 

[voodooless]

Now, all that said....I do think sealed is the best way to go ....for the smoothest rolloff down low and less phase rotation /group delay for better transients.

Well, given the same driver, you can only eq one way: make the closed follow the reflex. The other way around is basically not practical due to the steeper fall-off.

 

[Frgirard]

what speakers type are used by the double bass or the guitare bass players?

 

[gnarly]

Well, given the same driver, you can only eq one way: make the closed follow the reflex. The other way around is basically not practical due to the steeper fall-off.

True. If you are talking about one sealed box vs one ported box, with the same driver.

Now, make it two sealed boxes vs one ported box, and you can use EQ to cut the sealed boxes response down to the low freq corner.
(It might/probably will take more than two sealed boxes to match the low corner the ported version provides.)
This is the correct way to use sealed for its vaunted sonic superiority imo. Go biiger, and cut excess frequency response above the low corner.

Iow. it takes acoustic EQ (more displacement) to push up the low corner such that sealed stays superior to ported.

Practically, nobody wants more sealed boxes and usually not bigger boxes.
So yeah, they just dial up the boost on their sealed.
I just get tired of everyone saying doing that sounds better than ported...when a valid comparison has never really been undertaken.