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Are sealed speakers better for 2.1?


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So I was thinking, are sealed speakers better when you know you will be integrating a subwoofer?

 

From my understanding ported speakers have an advantage of being more efficient and being able to go lower than their sealed counterpart, and when comparing A to B on their own one might find these advantages more to their liking and the better overall speaker. A bookshelf for example might sound like a bigger speaker, while a sealed design might be missing the lower end to satisfy music listening and require a more powerful amp. On their own the advantages of one seem to outweigh the other and the reason for their popularity.

 

However, from my understanding sealed speakers are said to have better control of the driver and tighter more accurate bass (as seen in sealed subs), which leads me to wonder if they might be the better choice when you know  you will be integrating a subwoofer. A sealed speaker might not need to drop much below 80hz if you integrate a subwoofer, and you might be rewarded with better tighter bass from 80hz to 250hz.

 

Is there any validity to this thought or have I overlooked something? Are modern ported designs as good or nearly as good as their sealed counterparts these days maybe? Is bass roll off something else to consider? And finally, can I just plug my port and gain the advantages of a sealed enclosure, or is this not the same as a speaker designed from the start to be sealed.

Edited by Midget
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It depends also a lot on the woofer and what it’s best designed for. The holy grail is probably a sealed design that has the bass extension, tightness of both designs but minus the overhang of ported designs, which is very rare. I’ve heard a number of expensive sealed designs but very few or none have extended as well as a good ported design.

 

Generally agree if you are adding a sub then a sealed woofer system in the main speakers is good way to go, however many ported speakers with higher or lower bass extension frequency can work well also. Best to try both types and integrate with a particular sub and see which you like the best in the room acoustics you have.

Edited by Al.M
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16 hours ago, Irek said:

I would say speakers are better when they sound better regardless of the technical solution used. 

 

I think a better way to say this is and it applies to any piece of machinery:

 

Performance is performance regardless of how it is achieved.

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18 hours ago, Midget said:

However, from my understanding sealed speakers are said to have better control of the driver and tighter more accurate bass (as seen in sealed subs), which leads me to wonder if they might be the better choice when you know  you will be integrating a subwoofer. A sealed speaker might not need to drop much below 80hz if you integrate a subwoofer, and you might be rewarded with better tighter bass from 80hz to 250hz.

 

Is there any validity to this thought or have I overlooked something?

I think the only thing you may have overlooked is where the group delay in speakers are in the frequency range.

From my knowledge (it may be wrong) but most ported speakers are tuned in the 40-60Hz range and this frequency (and lower) is where the group delay will occur.

So if you crossover your ported speaker at 80Hz to a sub-woofer you are avoiding or mostly avoiding the group delay of the port because it's not contributing or not contributing much.

So the difference between a ported and sealed in the above scenario means practically identical performance.

Edited by Satanica
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18 hours ago, Midget said:

Are modern ported designs as good or nearly as good as their sealed counterparts these days maybe? Is bass roll off something else to consider? And finally, can I just plug my port and gain the advantages of a sealed enclosure, or is this not the same as a speaker designed from the start to be sealed.

Quite simply and I think you already know this a ported speaker vs a sealed speaker of identical drivers and volume will have pros and cons.


Yes, you can plug the ports in your speaker up. My general advice for what it's worth is not to; don't mess with the design.


As outlined in the previous post, if you're crossing over your speakers at 80Hz or even a bit lower to a sub-woofer the performance gain of sealed vs ported could be audibly very little or none.

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On 27/01/2020 at 9:54 PM, Midget said:

So I was thinking, are sealed speakers better when you know you will be integrating a subwoofer?

 

From my understanding ported speakers have an advantage of being more efficient and being able to go lower than their sealed counterpart, and when comparing A to B on their own one might find these advantages more to their liking and the better overall speaker. A bookshelf for example might sound like a bigger speaker, while a sealed design might be missing the lower end to satisfy music listening and require a more powerful amp. On their own the advantages of one seem to outweigh the other and the reason for their popularity.

 

However, from my understanding sealed speakers are said to have better control of the driver and tighter more accurate bass (as seen in sealed subs), which leads me to wonder if they might be the better choice when you know  you will be integrating a subwoofer. A sealed speaker might not need to drop much below 80hz if you integrate a subwoofer, and you might be rewarded with better tighter bass from 80hz to 250hz.

 

Is there any validity to this thought or have I overlooked something? Are modern ported designs as good or nearly as good as their sealed counterparts these days maybe? Is bass roll off something else to consider? And finally, can I just plug my port and gain the advantages of a sealed enclosure, or is this not the same as a speaker designed from the start to be sealed.

Edgar Villchur's  acoustic suspension principle is described here     https://en.wikipedia.org/wiki/Acoustic_suspension

it proved a sealed enclosure can be made to work with the loudspeaker itself to provide better frequency extension using smaller cabinets. 

 

It can be heard as intended, in particularly the classic AR speaker models, here the smallest, the AR7

 

 

 

   

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if you know you're going to cross to a sub, then IMHO sealed woofers in the mains are a better approach.

 

Ported speakers have lots of non linear behaviour going on depending on SPL - making integration with subs harder.

 

Ports are for speakers getting the best "in room" SPL at lower frequencies without a sub...

 

I do agree mostly with @Satanica's comments above - if you're crossing to the sub (ie hi pass on the mains) higher than where the port in the mains operates, then it may make minimal difference whether the mains are ported or sealed if you use a sufficiently steep high pass filter on the mains (eg at least 24dB/octave).

 

I would always recommend room EQ for good mains/sub integration, based on room measurements.

This process will manage the differences in ported/sealed mains integrating with subs...but having ports in the system does complicate things...

...IMHO why make it harder? - leave ports out on the mains if you know you'll cross to a sub.

 

On 27/01/2020 at 6:54 PM, Midget said:

A sealed speaker might not need to drop much below 80hz if you integrate a subwoofer,

No - crossovers aren't brick walls (ie infinitely steep) - how the mains cross over to the sub is an important consideration - you want an acoustic crossover (ie what you hear) where the mains combine evenly with the sub in amplitude and phase - not trivial to achieve, as the room response contributes massively in this region.

 

Say your main speakers are sealed and have a high pass response rolling off at 80Hz (ie 3dB down at 80Hz with a 2nd order/12dB per octave rolloff - the response for a sealed box).

Most subs have an electronic low pass filter, often set at 4th order 24dB/octave - if you choose 80Hz as the crossover frequency for the sub, the sub and mains wouldn't combine well in amplitude, phase or time.

 

If your sealed mains do rolloff at 80Hz, then you could add a 2nd order hi pass electronic filter at 80Hz to make it 4th order to combine better with the sub...or if your mains go much lower than that (at least below 40Hz), you could use an electronic crossover (edit hi pass and low pass) (24dB or steeper) at 80Hz between mains and sub.

 

IME you'll still need DSP to provide EQ and delay to achieve the best room response when integrating a sub.

 

On 27/01/2020 at 6:54 PM, Midget said:

And finally, can I just plug my port and gain the advantages of a sealed enclosure, or is this not the same as a speaker designed from the start to be sealed.

A qualified yes - plugging your ports properly, not with socks etc, will make your cabinet sealed, and it will behave/sound like a sealed box.

Using socks/anything else in the port will produce a different response - I won't comment on that. (edit -other than it's called an Aperiodic design)

 

Assuming you seal the port properly:

  • sealed enclosures/boxes are very forgiving on box size/volume -  you can change the box volume a fair bit with only minor changes in response (as opposed to ported where the box volume interacts with the port length/diameter)
  • for the same driver, a ported box will always be larger than a sealed box (edit assuming the typical alignments you would see in DIY)
  • if you seal the port on a ported box so it becomes a sealed box, it's just a box larger than you likely would have designed for a sealed enclosure...so it will have a lower Qtc (than a smaller sealed box) - this may mean some more droop in the pass band, but also slower rolloff
  • If you have sufficient EQ/power/Xmax, then Qtc is basically irrelevant - you can dial your own Qtc/speaker response using EQ within your limits of amp power and driver Xmax
  • Hoffman's iron rule always applies - the larger box will mean less EQ and power is required down low (but the same driver excursion)

None of my speakers are ported, although my sub is a tapped horn...I wouldn't run a tapped horn or ported enclosure in the middle of my system complicating crossovers

 

Mike

 

 

 

 

Edited by almikel
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25 minutes ago, almikel said:

Say your main speakers are sealed and have a high pass response rolling off at 80Hz (ie 3dB down at 80Hz with a 2nd order/12dB per octave rolloff - the response for a sealed box).

Most subs have an electronic low pass filter, often set at 4th order 24dB/octave - if you choose 80Hz as the crossover frequency for the sub, the sub and mains wouldn't combine well in amplitude, phase or time.

 

If your sealed mains do rolloff at 80Hz, then you could add a 2nd order hi pass electronic filter at 80Hz to make it 4th order to combine better with the sub...or if your mains go much lower than that (at least below 40Hz), you could use an electronic crossover (24dB or steeper) at 80Hz between mains and sub.

 

Indeed. Alternatively,  you could try to find a subwoofer with 2nd order low-pass. I ended up with a Tannoy TS2 for that very reason. It wasn't my ideal choice (not strictly a sealed sub with it's passive radiator), but it was 2nd order and fit my budget. My room treatment and final sub placement are still work in progress, but it should integrate well with my sealed speakers.

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14 hours ago, almikel said:

A qualified yes - plugging your ports properly, not with socks etc, will make your cabinet sealed, and it will behave/sound like a sealed box.

Using socks/anything else in the port will produce a different response - I won't comment on that.

But if you use tube socks will it sound warmer? ?

 

All kidding aside I am curious as the proper way to plugging the ports. The Kef LS50's I have come with their own plugs which are foamy and porous. Is this a proper seal or is this just to reduce the effects of the port? The previous speakers I owned had two ports and the plugs for the one port were much more dense and didn't let any air escape.

 

15 hours ago, almikel said:

for the same driver, a ported box will always be larger than a sealed box

 

Interesting, how would the overall size compare if the driver and box were larger in the sealed unit to match the same lower frequency range of a ported design. Do they equal out in size, or does it take a larger cabinet in a sealed design to match the same bass output.

 

15 hours ago, almikel said:

if you seal the port on a ported box so it becomes a sealed box, it's just a box larger than you likely would have designed for a sealed enclosure...so it will have a lower Qtc (than a smaller sealed box) - this may mean some more droop in the pass band, but also slower rolloff

How far off is a KEF LS50 for proper cabinet size to driver ratio if it were sealed? It seems like a rather small cabinet so maybe not that far off? 

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On 07/02/2020 at 12:25 PM, Midget said:

How far off is a KEF LS50 for proper cabinet size to driver ratio if it were sealed? It seems like a rather small cabinet so maybe not that far off? 

Generally, if you download free speaker box design software like Linear Team WINISD etc which have a data base of 90% of nearly all woofers made, model sealed vs ported for same woofer it can often be a difference of 30% box volume greater for the ported design. If correct the Kef Ls50 might be 9L ported vs 6L sealed design, however a 9L sealed or port plugged scenario would not sound that different to say a 6L sealed design, you probably struggle to hear the difference. Whereas the difference in sound between a 9L vs 6L ported design will be very audible in bass extension and quantity.

Edited by Al.M
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On 05/02/2020 at 8:29 PM, stereo coffee said:

Edgar Villchur's  acoustic suspension principle

 

Legend - Genius - Freak not that I knew him but over the last few months been reading a bit about the man while restoring an old pair of AR 2 ax's 

 

Reading the OP I think one of the key points to the discussion is "adding a sub" Most of the speakers I have used have been bookshelves, the smaller models ATC's (sealed) and B&W (front ported) I tried to intergrate a sub with limited success. I thought it would be a set and forget thing but found every recording required different bass enhancement, when I got it right it was great but for the most part, bit of a hassle. One thing I learnt was if your going to use a sub make sure it has a remote, you need to be in the listening position when tuning. Mine didn't, I'm no sub expert and got sick of jumping up and down real quick. 

 

I opted for larger bookshelves with 10" drivers and find with the right sorce no sub is needed.

 

At present I have the AR's (sealed) and some 4313b's (ported) both set up in the same room. Disregarding the pedigree and focusing on the design of the bass woofer, they both have their merits. It took a while to find the best position for the sealed which, so far, has ended up being low and tilted back with toe in. In this position I believe they could fill a large room with smooth controlled bass, too small a room and they can become boomy and sound better off the wall on stands. 

The ported are near field studio monitors so straight away not apples for apples yet the specs are very close. The bass is a lot crisper and doesn't linger. I'm trying not to quote what I've read and focus on my actual (layman) experience. 

 

I dont think bunging the ports turns them into a true sealed design, the woofers are set up differently for moving air around, can't speak for other brands but the originals (AR's) are all stuffed with fibreglass wool reducing the air volume which limits the voice coil movement. 

Most ported have some sort of baffle segregating the woofer and firing through the port. IMO bunging just gives you some extra options with positioning, which after all my waffle is the most important thing I've said. 

Positioning. 

 

@Midget I see your in NSW, PM me if your interested in having a listen 

 

 

 

 

Edited by Powerglide
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On 07/02/2020 at 4:39 AM, LogicprObe said:

 

I would class the use of a passive radiator as a sealed unit.

passive radiators have the same response as ported, but without the port related issues of "chuffing" and non linearities of ports wrt air velocity as SPL changes, assuming the passive radiator is specced properly...

 

...IMHO ports, passive radiators, tapped horns etc make sense in the subwoofer, as the port etc is not complicating the crossover between mains and sub.

I prefer to run sealed mains to minimise complications with the crossover to the sub/s.

 

Mike

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On 08/02/2020 at 10:42 AM, Powerglide said:

which after all my waffle is the most important thing I've said. 

Positioning. 

agreed - positioning of mains and subs, and choosing the best locations based on measurements, with some treatment and EQ thrown in, will make a far bigger difference than whether the mains are sealed or ported.

 

On 08/02/2020 at 10:42 AM, Powerglide said:

I dont think bunging the ports turns them into a true sealed design, the woofers are set up differently for moving air around,

air doesn't "move around" in a sealed box, the pressure just goes up and down, unless your box is really big/long. 

You can generate "modes" within a speaker box, but only at higher frequencies/shorter wavelengths where the dimensions of the box get closer to the wavelength of the sound being generated.

On 08/02/2020 at 10:42 AM, Powerglide said:

but the originals (AR's) are all stuffed with fibreglass wool reducing the air volume which limits the voice coil movement.

speaker stuffing actually increases the apparent volume of the box (by approx 5% or so), and at higher frequencies approaching/within the "modal" range of the speaker, will reduce/damp any resonances caused by modes within the speaker box.

Modes within a speaker box behave identically to room modes, and it's pretty easy to calculate if your speaker box is large enough to generate modes.

 

The lowest (in frequency) mode that can exist inside a speaker box is wavelength = longest internal dimension of the speaker box/2.

Let's say you had big floor standers with the woofer enclosure 1m internally.

So

Wavelength = 1m/2, the wavelength = 0.5m - this is the longest wavelength that will generate a mode in that speaker box.

V (velocity of sound 343m/s) = Frequency x Wavelength

F = 686 Hz - this is the frequency of the lowest mode that will be supported inside the speaker box.

 

If your woofer crosses to the mid or tweater say less than an octave below that (ie above 343Hz), I'd treat the inside of the woofer box with stuffing. If your woofer crosses to the mid/tweater below 340Hz, then modes internal to the speaker won't be an issue.

 

On 08/02/2020 at 10:42 AM, Powerglide said:

stuffed with fibreglass wool reducing the air volume which limits the voice coil movement. 

 

Adding stuffing to sealed boxes has the effect of slightly increasing the box volume, slightly lowering the Qtc, which will slightly change the frequency response - but not limit the voice coil movement if you apply EQ back to flat.

Consider a small sealed box (say Qtc around 1.0, ie with a small peak prior to rolloff, then dropping steeply), compared to a much larger sealed box (say a Qtc around 0.5, which is drooping prior to rolloff, but then not dropping as steeply as the small box)...

If you applied EQ to each example to achieve the same frequency response, they would have the same excursion of the voice coil (ie driver excursion) - just different power requirements - with the larger box requiring less EQ and less power below rolloff (Hoffman's Iron Rule at play).

 

Mike

 

 

 

 

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On 05/02/2020 at 8:16 PM, LogicprObe said:

 

Sealed speakers are always better.

 

edit - I should qualify that with 'properly designed'...........

In the context of this thread - ie box main speakers that are intended to have a sub below them, compared to ported/passive radiator designs - I would agree... there are obviously other options for main speakers (open baffle, electros, maggies etc etc) beyond the scope of this thread.

 

Coming back to "typical" box speakers - in a DIY context, sealed designs are virtually impossible to get wrong - they are just not that sensitive to box volume variations - especially if you have EQ and reasonable amp power available.

Ported designs are a completely different ball game - much harder to design, and finicky wrt driver actual response (compared with on paper specs) and box volume/port diameter and length...any "well designed" ported enclosure IMHO requires prototyping...as a lazy DIYer I don't bother - sealed designs just work.

 

On 05/02/2020 at 8:16 PM, LogicprObe said:

Sealed speakers are always better.

 

On 07/02/2020 at 5:25 AM, jessandkerry said:

Always better for bass, just need to be big enough with the correct driver to get low enough, that's the problem they have.

Jess

In the context of this thread, for main speakers crossing to a sub, I agree sealed mains are a better approach.

 

But sealed mains enclosures don't need to be large, and many drivers are available that get low enough - you just need EQ/driver excursion/amp power available to cross to a sub.

 

In my case my "mid bass" drivers are Acoustic Elegance TD18's in sealed 60 litre boxes - their natural high pass rolloff in their boxes is around 100Hz - this isn't a "problem", as I have ample EQ/excursion/power to push the TD18's down to 50Hz or so to cross to the sub.

 

Going a bit off topic, I don't agree that "sealed" is always better for bass when discussing the bottom octave (ie below 40Hz) - I'm discussing subs now - not mains crossing to subs.

The power/driver excursion required from sealed enclosures to hit decent SPL targets "in room" below 40Hz does get larger the lower you go - so I agree with your point that sealed enclosures may have a problem when you run out of amp power/driver excursion.

 

I'm OK with using other designs for the bottom octave - I built a dual driver/dual amp tapped horn for my sub.

From a DIY perspective tapped horns are tricky to design - being a lazy DIY'er, I just bought @Paul Spencer's T20 tapped horn design/amps/drivers, and I just made some sawdust and an awesome sub.

 

One of Paul's blog posts compares my drivers/amps in sealed boxes compared to the same drivers in the T20 tapped horn enclosure:

http://redspade-audio.blogspot.com/2012/02/how-does-sensitivity-of-tapped-horns.html

 

From Paul's blog, "So the result is that two 12" drivers with 370 watts each can achieve the same output as eight (my edit: drivers) with twice as much power. Since drivers and amps are much more expensive than a few sheets of cheap ply, this works out as a cost effective choice."

 

This is Hoffman's Iron Rule at play combined with the trade-off tapped horns have of being narrow band devices, but being highly efficient within their band...and requiring steep crossovers.

 

I use a symmetrical 24dB LR crossover between my T20 sub and TD18s at 50Hz, with a bunch of EQ to push the TD18s down below 50Hz...then I apply room EQ...

 

...the room response is pretty flat down to around 20Hz or so, falling off below 15Hz.

 

The difference the T20 sub makes is very subtle - it just adds "weight" in the bottom octave.

 

All the bass slam comes from the TD18s - listening to the TD18s in a treated room with the bass "reasonably" under control is a revelation - tight/dry bass that slams you in the chest, with the sub adding weight below...

 

...when deciding what mid bass drivers to use to match to my PSE144's, Paul Spencer said, "if you can afford TD18's, go with them"...fantastic advice - I've never heard mid bass like my TD18s in their "small" sealed boxes (and treated room). 

 

The TD18's need a sub below - but being sealed it made the integration with the T20 sub below that much easier.

 

cheers

Mike

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