Sealed/Ported Speakers

[CJSF]

No one has mentioned the suitability of one type of speaker to a particular type of music . . . ? Often mentioned in 'which speaker' answers on here? Rock music for instance can sound better better on ported speakers? ie loads of overblown bass . . .

As I listen to a wide variety of music, from jazz, country and folk, through rock to large pipe organs . . . I find the 'transmission line' speaker well suited as it can produce deep clean powerful base, and yet with the right tweeter (silk dome preferred) has a sweetness at the top end that is beguiling with out being wearing. That said, a small 'sealed cabinet' speaker can have imaging capabilities that are remarkable, LS35a types.

Pays your money, take an informed choice . . . ?

 

[davedotco]

Hiya folks, thanks for the replies.

TBH, most of this stuff is over my head. I just wanted to know the basic differences, and their merits/drawbacks.

Thanks for the link Dave, but after a bit, it seemed like rocket science. See? I told you I wasn't the brightest

In all honesty I do not think that the whole sealed or ported debate is particularly important. there are good and bad designs of either type.

Most modern speakers are ported, this helps with sensitivity and gives the designer more choices in how the driver and cabinet interact and this is very important at the bass end.

The problem for me is the choices that the designer makes. At the budget and mid-fi areas the choices are usually to maximise the bass output, usually at the cost of control. As CJSF says above, lots of bass sells so that is what is produced, one of the main reasons I have so little time for inexpensive, mass market speakers.

It is this emphasis on bass quantity over quality that makes ported speakes so room dependent and hard to place, it's a design choice not a function of ported speakers per se.

Furthermore, unless you are placing speakers tight to a wall it does not matter, placement wise, whether the port is on the front or the rear. Boundary effects are well understood and have everything to do with the dispersion characteristics of the speaker, nothing much else.

 

[DocG]

Furthermore, unless you are placing speakers tight to a wall it does not matter, placement wise, whether the port is on the front or the rear. Boundary effects are well understood and have everything to do with the dispersion characteristics of the speaker, nothing much else.

Yep, the Wilson Duettes have a bass port on the rear and they are designed for placement close to a wall (or even in a cabinet).

Wilson even provide a "rough-out kit" for in-wall placement -- though I'm not sure what happens with the bass port then... :?

 

[Freddy58]

Dave, as an aside, are you familiar with the Kef Concord lV's? If so, what were your impressions?

I should take that as a "no" then?

 

[davedotco]

Furthermore, unless you are placing speakers tight to a wall it does not matter, placement wise, whether the port is on the front or the rear. Boundary effects are well understood and have everything to do with the dispersion characteristics of the speaker, nothing much else.

Yep, the Wilson Duettes have a bass port on the rear and they are designed for placement close to a wall (or even in a cabinet).

Wilson even provide a "rough-out kit" for in-wall placement -- though I'm not sure what happens with the bass port then... :?

At a guess I would say that the kit allows the air to leak out into the room. Soffit (in wall) mounted monitors are common in studios but usually the port is integrated onto the front baffle.

As far as I can tell, the primary reason for placing the port on the rear is to stop internal reflections of higher frequencies exiting the port and being audible to the listener. I have heard this effect and it is not good.

Port noise caused by low frequencies is usually caused by the bass driver being driven into the very low bass, as we have discussed in another thread ported designs suffer from excessive cone movement when the loading on the cone reaches a minimum, usually an octave below resonance.

Another very good reason for decent high pass filtering in amplifiers. For what it is worth, most pro-style active monitors limit this with filters in the amplifiers, some are switchable, some not.

 

[davedotco]

Dave, as an aside, are you familiar with the Kef Concord lV's? If so, what were your impressions?

I should take that as a "no" then?

Actually I was just checking.

I had a pair of either Concord III or IVs, can't remember which, in around 1980. Memory says it was the IIIs but could be wrong. They would have been on the end of a simple, basic LP12 setup, and probably at that time, a Nytech or a Naim 42/110, I can not remember the details but they came and went very quickly indeed, so not to my taste at all.

 

[Freddy58]

Dave, as an aside, are you familiar with the Kef Concord lV's? If so, what were your impressions?

I should take that as a "no" then?

Actually I was just checking.

I had a pair of either Concord III or IVs, can't remember which, in around 1980. Memory says it was the IIIs but could be wrong. They would have been on the end of a simple, basic LP12 setup, and probably at that time, a Nytech or a Naim 42/110, I can not remember the details but they came and went very quickly indeed, so not to my taste at all.

The lll's were the same as lV's, just cosmetic differences. I had some with my last set-up, and was well impressed. Horses for courses

 

[davedotco]

Dave, as an aside, are you familiar with the Kef Concord lV's? If so, what were your impressions?

I should take that as a "no" then?

Actually I was just checking.

I had a pair of either Concord III or IVs, can't remember which, in around 1980. Memory says it was the IIIs but could be wrong. They would have been on the end of a simple, basic LP12 setup, and probably at that time, a Nytech or a Naim 42/110, I can not remember the details but they came and went very quickly indeed, so not to my taste at all.

The lll's were the same as lV's, just cosmetic differences. I had some with my last set-up, and was well impressed. Horses for courses

I can't remember the details but I do know that I was looking to upgrade my old AR18s and went through quite a few speakers at that time. The AR18s had a tight, slightly 'slappy' bass that was very articulate, improving on them proved to be pretty difficult. I went through about half a dozen or more speakers that did not do it for me, the Kefs were just one of them.

I ended up with a pair of ATR100 monitors, German speakers with a big 7 inch bass mid (with a metal centre dome FFS) and the then ubiquitous Peerless tweeter. All in big flimsy enclosures that really should not have worked but were great. Bit big though, which is why they eventually had to go.

 

[Freddy58]

Dave, as an aside, are you familiar with the Kef Concord lV's? If so, what were your impressions?

I should take that as a "no" then?

Actually I was just checking.

I had a pair of either Concord III or IVs, can't remember which, in around 1980. Memory says it was the IIIs but could be wrong. They would have been on the end of a simple, basic LP12 setup, and probably at that time, a Nytech or a Naim 42/110, I can not remember the details but they came and went very quickly indeed, so not to my taste at all.

The lll's were the same as lV's, just cosmetic differences. I had some with my last set-up, and was well impressed. Horses for courses

I can't remember the details but I do know that I was looking to upgrade my old AR18s and went through quite a few speakers at that time. The AR18s had a tight, slightly 'slappy' bass that was very articulate, improving on them proved to be pretty difficult. I went through about half a dozen or more speakers that did not do it for me, the Kefs were just one of them.

I ended up with a pair of ATR100 monitors, German speakers with a big 7 inch bass mid (with a metal centre dome FFS) and the then ubiquitous Peerless tweeter. All in big flimsy enclosures that really should not have worked but were great. Bit big though, which is why they eventually had to go.

Yeah, that's my only concern. The Concords have 8" drivers, so will need large cabinets...

 

[JMacMan]

Back in the days when I owned some B&W DM2a's, a friend had a pair of AR3a's which I had on loan for a few weeks whilst he was working away from home, and was able to do some lengthy A/B comparisons.

A lovely speaker indeed the AR3a, albeit very different sounding to the B&W.

One point perhaps worth mentioning, is that most ported speakers roll off in the bass at atypically 24db per octave and sealed/acoustic suspension designs circa 12db per octave.

So, with boundary re-inforcement, and all other things being equal, the sealed box may actually go slightly lower in frequency, but probably not as loud a couple of octaves up as the ported model.

It's a personal thing; I don't particularly like ports unless they're really well done; too many cheap ported box speakers I've heard have too much noise coming out of ports which tends to muddy up the midrange.

Yes, I'm making sweeping generalisations, but IMHO there's a big difference in the port design and implementation in something like a B&W 800 series speaker, and my otherwise much more modest Tannoy MX2's.

My current Lab 9's have sealed enclosures for all the drivers; those in the bass are 10" and have a 500 watt ICE power amp behind them, and they also have ABL, or Adaptive Bass Linearisation/Equalisation, so despite the relatively small cabinets, they have outstanding bass in terms of control, grip, drive, extension and accuracy. Going by dealer comment (which I agree with) and on rough calculations from their specs, they're also capable of a solid 20hz in room, which suits me down to the ground being something of a pipe organ afficianado.

Certainly they can punch you in the chest with bass that you can barely hear, rattle the windows and make the couch go all wobbly at the same time on movie LFE effects.

Works for me..

Cheers

JMac :cheers:

 

[davedotco]

Back in the days when I owned some B&W DM2a's, a friend had a pair of AR3a's which I had on loan for a few weeks whilst he was working away from home, and was able to do some lengthy A/B comparisons.

A lovely speaker indeed the AR3a, albeit very different sounding to the B&W.

One point perhaps worth mentioning, is that most ported speakers roll off in the bass at atypically 24db per octave and sealed/acoustic suspension designs circa 12db per octave.

So, with boundary re-inforcement, and all other things being equal, the sealed box may actually go slightly lower in frequency, but probably not as loud a couple of octaves up as the ported model.

It's a personal thing; I don't particularly like ports unless they're really well done; too many cheap ported box speakers I've heard have too much noise coming out of ports which tends to muddy up the midrange.

Yes, I'm making sweeping generalisations, but IMHO there's a big difference in the port design and implementation in something like a B&W 800 series speaker, and my otherwise much more modest Tannoy MX2's.

My current Lab 9's have sealed enclosures for all the drivers; those in the bass are 10" and have a 500 watt ICE power amp behind them, and they also have ABL, or Adaptive Bass Linearisation/Equalisation, so despite the relatively small cabinets, they have outstanding bass in terms of control, grip, drive, extension and accuracy. Going by dealer comment (which I agree with) and on rough calculations from their specs, they're also capable of a solid 20hz in room, which suits me down to the ground being something of a pipe organ afficianado.

Certainly they can punch you in the chest with bass that you can barely hear, rattle the windows and make the couch go all wobbly at the same time on movie LFE effects.

Works for me..

Cheers

JMac :cheers:

Jmac is quite correct here.

However if the designer chooses he can use (tune) the port to extend the bass response rather than simply boost the bass as occurs in most mass market speakers. If this is done correctly then the bass in a ported enclosure stays flat a little deeper but then rolls off more rapidly, often a very good thing as it rejects sub bass that most sensible size speakers can not reproduce.

It's a design thing, speakers with lots of bass sell, even though it is muddy and often unrelated to the music being played.

 

[Freddy58]

Hiya Dave. It's a pity you don't remember how they sounded, as you might have been able to suggest improvements. As I've said in other posts, it's my intention (at this point) to build some speakers based on thos old Kefs. I suppose I hope that I'm not remembering them with rose tinted glasses. If I were to go ahead with the build, I have the opportunity to modify the sound, as Wilmslow seem to be pretty much switched on to the sound of the Kefs, and would be able to suggest units to make any adjustments, to suit.

 

[hifikrazy]

There's a case to be made for aperiodic bass loading as well, which Richard Allen from EB Acoustics has also been singing its praises. I had a pair of Wharfedale Jade 5 before my current speakers which had aperiodic bass loading, and it produced tight, punchy, fast and defined bass with sufficient depth and weight. In fact I think the overall bass quality was better than my Spendor D7, but too bad the midrange and highs didn't match the naturalness of the Spendor otherwise it would be a "perfect" speaker.

 

[Richard Allen]

Hi.

There's a difference to 'my aperiodic' and the Jade tho. When I was talking to Peter Comeau a couple of years ago I seem to remember him saying that the second chamber did in fact connect with the room although not in the same way as a reflex design.

'My' solution will still be essentially a closed box. That is to say no connection with the room volume. I am aiming for the mids and highs of EB2 but (possibly) another octave in the bottom end. I'll keep you informed.

 

[Freddy58]

Hiya Dave. It's a pity you don't remember how they sounded, as you might have been able to suggest improvements. As I've said in other posts, it's my intention (at this point) to build some speakers based on thos old Kefs. I suppose I hope that I'm not remembering them with rose tinted glasses. If I were to go ahead with the build, I have the opportunity to modify the sound, as Wilmslow seem to be pretty much switched on to the sound of the Kefs, and would be able to suggest units to make any adjustments, to suit.

Out of interest Dave, do you think that speakers are much better these days? Probably a naive question....I ain't afraid to ask though

 

[davedotco]

Hiya Dave. It's a pity you don't remember how they sounded, as you might have been able to suggest improvements. As I've said in other posts, it's my intention (at this point) to build some speakers based on thos old Kefs. I suppose I hope that I'm not remembering them with rose tinted glasses. If I were to go ahead with the build, I have the opportunity to modify the sound, as Wilmslow seem to be pretty much switched on to the sound of the Kefs, and would be able to suggest units to make any adjustments, to suit.

Out of interest Dave, do you think that speakers are much better these days? Probably a naive question....I ain't afraid to ask though

I think that the improvements in drive unit technology allow the designers to make far better speakers than was the case 20 or 30 years ago.

I think it is a great pity that so few of them bother to do so.

 

[Freddy58]

Hiya Dave. It's a pity you don't remember how they sounded, as you might have been able to suggest improvements. As I've said in other posts, it's my intention (at this point) to build some speakers based on thos old Kefs. I suppose I hope that I'm not remembering them with rose tinted glasses. If I were to go ahead with the build, I have the opportunity to modify the sound, as Wilmslow seem to be pretty much switched on to the sound of the Kefs, and would be able to suggest units to make any adjustments, to suit.

Out of interest Dave, do you think that speakers are much better these days? Probably a naive question....I ain't afraid to ask though

I think that the improvements in drive unit technology allow the designers to make far better speakers than was the case 20 or 30 years ago.

I think it is a great pity that so few of them bother to do so.

I notice that quite a few speakers these days employ relatively small drivers. Do you see this as an issue? Is it really possible to get a 'big' sound from small drivers? I appreciate it's a simplistic question, but I'm talking in general terms....

I guess I'm asking, does size matter?

 

[Al ears]

'There ain't no alternative to cubic inches' ......

To be honest I think size does matter. Everything else is a compromise in attempting to get those lower octaves out of a box that should not be able to produce them.

Until very recently I have not been able to get 'proper' bass since I got rid of my old (original) Heybrook HB3's, and they had a 10" woofer.

You will a lot of 'hi end' (Wilson's for example) insist on using similar sized woofers. Generally though, in order to fit in with current acceptable speaker sizes, compromises have to be made (ports / transmission lines). These all help in creating a 'non-flabby' bass but ultimately cannot produce those low Hz values obtained by conventional big woofers.

Blame modern living.

 

[nopiano]

As a slight aside, there are also ABR (auxiliary bass radiator) speakers, that is ones with a dummy cone in place of a port. In essence the aim is to boost the bass output by having a greater radiating area, but adding some control that an open port may lack.

I was never a fan of the principle, as KEF were an exponent a few decades ago and I mostly disliked their speakers in any case. (Older Codas were OK and the LS50 is great, but otherwise they often don't do much for me).

I see wikipedia calls them Passive Radiator. It happens that my SFs have an ABR. [And my first speakers were AR4xa with 'acoustic suspension']

 

[Freddy58]

'There ain't no alternative to cubic inches' ......

To be honest I think size does matter. Everything else is a compromise in attempting to get those lower octaves out of a box that should not be able to produce them.

Until very recently I have not been able to get 'proper' bass since I got rid of my old (original) Heybrook HB3's, and they had a 10" woofer.

You will a lot of 'hi end' (Wilson's for example) insist on using similar sized woofers. Generally though, in order to fit in with current acceptable speaker sizes, compromises have to be made (ports / transmission lines). These all help in creating a 'non-flabby' bass but ultimately cannot produce those low Hz values obtained by conventional big woofers.

Blame modern living.

I kinda figured as much. Thanks Al