Sealed speakers VS ported

[dualazmak]

Hello OP @Mackie,

My ongoing "post series" here and thereafter, would be also your reference and interests.

 

[Chrispy]

@Newman what is the role of volume control of a subwoofer, never having used one, if listening at moderate levels to bookshelf speakers I have read elsewhere you should hardly be able to tell if the sub is on? Is that correct?

Should be to match to the volume level of your speakers and then left alone for the most part. A sub is generally subtle rather than in your face unless you set it up for the latter....which some do.

 

[Freeway]

And what about passive radiators? Middle ground?

 

[Newman]

@Newman what is the role of volume control of a subwoofer, never having used one, if listening at moderate levels to bookshelf speakers I have read elsewhere you should hardly be able to tell if the sub is on? Is that correct?

Hi there, as Chrispy noted, the volume control is there to make a set-and-forget level matching of the subwoofer’s loudness compared to the main speakers.

Compared to bookshelf speakers? You will definitely know if the sub is on, as soon as you put on something like Daft Punk moderately loud.

Compared to full range floorstanding main speakers that reach into the 30’s Hz, the sub will, once well adjusted, have a subtle effect, but don’t mistake that for might-as-well-not-have-it. My experience has been that even the subtle effect soon makes one glad one has it, because all music begins to sound like it has a natural solid foundation of rightness. The effect can run right through all octaves: I have heard a slightly glassy treble settle into niceness with the addition of a well-tuned sub, probably because it has been balanced by the low-down weight, instead of being left exposed by itself.

Hope I am not being too esoteric and make some sense to you.

cheers

 

[thewas]

The effect can run right through all octaves: I have heard a slightly glassy treble settle into niceness with the addition of a well-tuned sub, probably because it has been balanced by the low-down weight, instead of being left exposed by itself.

That is true, whenever I thought I had mid/treble problems with good neutral loudspeakers the real reason was the bass region which wasn't enough on level and depth or had wide dips.

 

[gnarly]

That is true, whenever I thought I had mid/treble problems with good neutral loudspeakers the real reason was the bass region which wasn't enough on level and depth or had wide dips.

Newman, thewas, add me to the list who thinks this phenomenon is true.

I've come to see tonal balance as just that.......a balance..... like a see-saw, or a weight measuring balance-scale.
It seems the fulcrum of the balance is right in the middle of the 10 octaves, so say in the 600-700Hz range.

If tonality is out of balance, in order to correct that, weight can either be added on one side, or taken away on the other.

 

[thewas]

I've come to see tonal balance as just that.......a balance..... like a see-saw, or a weight measuring balance-scale.
It seems the fulcrum of the balance is right in the middle of the 10 octaves, so say in the 600-700Hz range.

Exactly, we perceive tonality relatively like a pair of scales, that's why the great Peter Quad had implemented also the tilt control on his amps

Tilt Tone Control for Headphones / Speakers

Hello folks, I've created a simple wide acting Tone Control Filter that can be used in any of your parametric EQ software of choice (details of the filter later in this post). As a lot of us know there's this thing called "Circle of Confusion" which I think could have been a phrase coined by...

www.audiosciencereview.com

 

[FrantzM]

Hi

The only realistic advice so far was to familiarize with objective measurements or--if You are willing to do it the hard way, many trials of equalizing with just Your ears as a measurement device. You will most probably prefer a technically good bass: flat and even with some depth.

Mackie, a ported design follows quite different rules than a sealed one. A ported device with the same internal volume would only need half the excursion, or half the cone area. How many 'watts' a specific output needs depends on the enclosed air volume alone (nearly), while a ported design is about 6dB more effective.

With ported another parameter comes into play. The tuning frequency limits the usable bandwith quite sharply. Only little below the tuning the ported box would undergo a mechanical short circuit. effect Imagine an electrical short at a power mains socket, and You get the picture. The cone would exhibit hefty movement without radiating sound. This modulates the mids dramatically; the speaker is useless.

Problems with the latter quickly arise, if a too small box was tuned too high as to extend kind of a "linear" response, the infamous -3dB point, to a too low frequency. E/g:
- box tuned to 55Hz in order to say f-3 is at 50Hz.
- The same driver in the same volume might otherwise be tuned to 40Hz, being relatively safe with the short circuit, but then f-3 would be at say 65Hz.

This more or less sensible decision, too often opting for the ugly side, might contribute the most to the--in the enthusiast camp, bad reputation of ported designs. Conversely, in a small room the f-3 at 65Hz could be just right to avoid booming (from the room!). Such a design would as a well designed ported one benefit further in efficiency and reduced cone movement, hence a lot clearer mids.

So far and final from my side without any hearsay The topic is in waves "decaying" already ...

Don't know enough to dispute the validity of your reply. I've read a few times, it doesn't seem to address the question in, my honest and humble opinion : What does happen if one stuffs the port(s) of a speaker?
To my understanding, "stuffing" doesn't create a perfect seal. It certainly does affect the bass output of the speaker but ... As a matter of fact, some subwoofers do offer this as a feature , eg. HSU VTF-xxx

I can understand it reduces/limit the low bass response of the speaker and limit its excursion at low frequencies by presenting a higher acoustic impedance to the driver.. I am speculating but need to understand:
What does happen, when you stuff the port of loudspeaker (not of a subwoofer)? It is beneficial in the case use of mains with stuffed port + Ported or sealed subwoofers ?

Peace.

 

[dualazmak]

I assume "theoretical discussion" would always tend to be "endless theoretical discussion".

Along with the invaluable "theoretical discussion", we may better to objectively measure the transient behavior/characteristics and time alignment of our own sub-woofer and/or woofer excited by single wave tone (in specific Fq, i.e. 40 Hz, 50 Hz, 65 Hz, 100 Hz and 130 Hz?) or by multiple wave (3-wave or 8-wave) rectangular tone burst of various Fq; as I wrote in my above post #56 and post #58.

 

[fineMen]

Don't know enough to dispute the validity of your reply. I've read a few times, it doesn't seem to address the question in, my honest and humble opinion : What does happen if ...

O/k, the answer is available by concluding it from my input. To 'seal' a ported design afterwards throws away 95% of the thought that got into it (if well done). The drivers are of different specification. The match--in size alone, is different. In short, to stuff a ported box' port would be a desperate attempt to correct the consumers previous poor decision making.

I think I can tell because I've evaluated so many pretty nasty designs of my own. But, in this case for sure, all my caveats address the potential for optimization. If one is willing to pay the double amount for the same objectively measurable performance, she will do anyway.

 

[FrantzM]

O/k, the answer is available by concluding it from my input. To 'seal' a ported design afterwards throws away 95% of the thought that got into it (if well done). The drivers are of different specification. The match--in size alone, is different. In short, to stuff a ported box' port would be a desperate attempt to correct the consumers previous poor decision making.

I think I can tell because I've evaluated so many pretty nasty designs of my own. But, in this case for sure, all my caveats address the potential for optimization. If one is willing to pay the double amount for the same objectively measurable performance, she will do anyway.

Thanks I was thinking about stuffing the port of my LSR308, not that I hear anything wrong abou them ... won't do it.
On that, would it make sense to use a high pass filter on the 308, to limit the excursion of the mid-woofer driver? I use 2 (soon to be, 3) subwoofers crossed at 60 Hz...


Peace.

 

[ernestcarl]

On that, would it make sense to use a high pass filter on the 308, to limit the excursion of the mid-woofer driver? I use 2 (soon to be, 3) subwoofers crossed at 60 Hz...

What do your measurements (e.g. distortion figures) and listening comparison tests say? Those are the only things that matter. If you listen at low to moderately low volumes and never ever drive the speakers to compression, it probably doesn't matter all that much.

 

[moonlight rainbow dream]

And what about passive radiators? Middle ground?

No. PR operates on the same principle as ported. The backwave energy from speaker driver that would otherwise be wasted is used to vibrate a tuned mass, contributing low frequency output. It does confer some advantage for enclosure size when it comes to very small speakers or very large subs. Also, you don't have to deal with port resonances. The advantages are offset by the increased cost of adding PRs to a design vs ports.

 

[thewas]

O/k, the answer is available by concluding it from my input. To 'seal' a ported design afterwards throws away 95% of the thought that got into it (if well done). The drivers are of different specification. The match--in size alone, is different. In short, to stuff a ported box' port would be a desperate attempt to correct the consumers previous poor decision making.

That sounds more dramatic than it is, in the end a port is a resonator which uses some of the rear transmitted energy to boost a specific region, many good engineering loudspeaker makers provide bungs to close the ports to modify the bass response according to the needs.

Thanks I was thinking about stuffing the port of my LSR308, not that I hear anything wrong abou them ... won't do it.
On that, would it make sense to use a high pass filter on the 308, to limit the excursion of the mid-woofer driver? I use 2 (soon to be, 3) subwoofers crossed at 60 Hz...

When planned to with subwoofers stuffing the port of the satellites has often several advantages as for example steeper roll-off and less need to modify the electrical slopes and of course reduction of the parasitic noises coming from the ports. Best is always of course to measure, listen and decide for each case yourself.

 

[fineMen]

Thanks I was thinking about stuffing the port of my LSR308, ... to limit the excursion of the mid-woofer driver?

As I said, depends on the tuning frequency. Given the most extreme low bass recordings You listen to, if the tuning is not too high, the ported speaker, equalized properly, wins.
The tuning frequency is a critical parameter of ported designs because of the loss of 'loading' below. 40Hz should be quite well on the safe side for musical presentations. The so called home theatre may call for 20Hz if it was for the most popular genres.

There are no simple rules. Why is it that the expert's shop around the corner fell out of fashion? Good advice cannot be valued enough. But it needs data to play with.

 

[restorer-john]

Post number #2 by @Jim Shaw nailed it.

 

[restorer-john]

And what about passive radiators? Middle ground?

Passive radiators are much better than ports, because they keep the pieces of lego, random toys and critters out of your speakers.

 

[fineMen]

An observation from a bass player.

I've noticed that I seem to prefer the bass response on sealed speakers over ported ones.
Bass guitar notes appear tighter , have more texture, definition and notes just appear to be more even sounding through the range of a bass guitar.
With ported designs I always seem to hear some bass notes louder or weaker.

Are ported designs generally less accurate in bass response or have I just not listened to the right speakers?

What You as a musician experience as more accurate is ... an accentuation on the harmonics. ... We could meet, though, as to discuss the mathematical foundations of the western tonal system ;-) I do not 'believe' in the Pythargorean comma and discard the circle of fifths alltogether ...

The advice that You, in case could have the depicted effect with using an equalaizer was already given. No offenses,

 

[restorer-john]

What You as a musician experience as more accurate is ... an accentuation on the harmonics. Alas, all Your terms to discribe the imaginative merits of sealed versus ported appear ill defined to a technician. Nobody, really, expects me to play the bass properly, neither should anybody expect You to discuss speakers. So, no offense. Or would someone stand a battle of incompetence, namely me playing the bass and You derive generalizations in tech in all public? We could meet, though, as to discuss the mathematical foundations of the western tonal system ;-) I do not 'believe' in the Pythargorean comma and discard the circle of fifths alltogether ...

The advice that You, in case could have the depicted effect with using an equalaizer was already given. No offenses,

WTF have you been smoking?

 

[fineMen]

WTF have you been smoking?

Sorry for the harshness. But again a simple question revealed much of the naivety of the common audiophile. With all my apologies.