Why Are Ported Speakers the Dominant Design?

[watchnerd]

I'll put forth the proposition that the easiest way to put together a high quality full range or nearly full range system on a budget is to match a 2 way acoustic suspension speaker with a woofer no larger than 6 or 7 inches and match it with a sub(s) ported or acoustic suspension, the former being more economical albeit at the expense of some loss of transient response.

This is not an original thought as a previous poster references Welti (of Harman and multisubs) as advocating this approach.

I'm curious what the cost-no-object option is for this?

Most of the "big scale capable from the upper mid-bass upwards" 2-ways I can think of off the top of my head are ported....

 

[watchnerd]

What about "aperiodic loading"?

https://diyaudioprojects.com/Technical/Aperiodic/

http://www.teamaudionutz.com/tutorial/1/AP_Enclosures-The_Aperiodic_Cookbook

 

[Juhazi]

The aperiodic port leaks pretty much more "noise" than BR. Aperiodic has never been popular, more a curiosity. But sort of this kind open backside is sometimes used with the midrange of 3-way speakers, eg. these. The designers just say that the backside "leak" enhances the sound, adds spatial "naturalness" etc., no measurements shown.

http://www.troelsgravesen.dk/ATS-4.htm
http://speakerdesignworks.com/MiniStatements.html

 

[Wombat]

You're funny.

Looking forward to more concise replies.

Those answers you were seeking can be found here:

Beranek Start at page 1. and you will be prepared for Part XXII: Bass Reflex Enclosures(page 374).
Leo summarises the math in clear prose along the way.

From the book, Acoustics: Sound Fields, Transducers and Vibrations, by Leo Beranek and Tim Mellow.

 

[dc655321]

I am a fan of the elegant simplicity of the sealed enclosure. But, I am also honestly not certain I could discriminate ported from sealed without peeking.

I'm also not convinced that a ported system is represented by a parallel topology. Does the speaker not drive the output of the port?
OTOH, it seems clear that reflections can constitute a non-minimum-phase system. I am happy to learn otherwise in either case.

You're wrong.

In the case of a bass reflex speaker we are not merely cascading responses, we are adding them - we hear the speaker driver and the output of the port. Intuitively, we can't correct the sum of the two (make it into a single transient impulse) because the port 'echoes' whatever we do with the cone - possibly with a larger output. Even with a complex model, we can't invert the system because the result is unstable, needing to provide larger and larger corrections.

The quote from your link is missing a (IMO) key piece of information (italicized):

It is also worth noting that if minimum-phase LTI systems are connected in series, the overall system remains minimum phase. The similar property does not hold in the case of systems whose responses are added: the responses of minimum phase system components when added produce a result which is typically not minimum phase

A series arrangement of minimum-phase systems will remain a minimum-phase system in totality.
A parallel topology of minimum-phase systems may not produce a minimum phase system.

A discrete minimum-phase system will have all poles and zeroes in the unit circle. Since all poles/zeroes are less than +/-1, the poles/zeroes of the product of any such systems will also be less than +/-1. The same cannot be said when summing poles/zeroes, as in a parallel topology.

 

[q3cpma]

Atmospheric vs turbocharged engines: the thread. Passive radiator is supercharged, maybe?

 

[Ron Texas]

Atmospheric vs turbocharged engines: the thread. Passive radiator is supercharged, maybe?

Not really. Nobody is stuffing air into the box. Superchargers are of limited use due to fuel efficiency concerns. I suppose you could say a turbo gets more power per liter of engine than atmospheric and that ports get more bass per liter of enclosure, but it just kind of rhymes.

 

[dc655321]

Not really. Nobody is stuffing air into the box. Superchargers are of limited use due to fuel efficiency concerns. I suppose you could say a turbo gets more power per liter of engine than atmospheric and that ports get more bass per liter of enclosure, but it just kind of rhymes.

But, passive radiators and port reflex designs are dependent upon the output of an "engine".
So, I guess there is the "powered by exhaust" analogy to be made, if you squint really hard... ;-)

 

[Snarfie]

Many don't like the quick decays of sealed cabinets.

I don't know if bass reflex cabinets are actually cheaper given all the work hours speaker tuning them and dealing with leakages.

I can relate to that did a restoration regarding my JK acoustic 3 speakers it has a bass cabinet that is sealed from the upper part where the mid an tweeter are located. After 35 years the sealed part leaked/was gone i had to pull back most staples en isolate the top part inside the cabinet. The whole bass did sound completely different way more detaild an punchy. Also the mid-toners who suffered from the excessive air that leaked into the top cabinet caused around 300 Hz for resonance in to the mid-toners. after i did the isolation the resonance was for 50% gone. The other 50% is done by Audiolab.nl who cleand an aligned the speaker coils to keep as much the original speaker sound. At that point they sounded as they should. Ha ha 3 month later i got hold of Vandersteen model 1 speakers who where regarding staging way better. I'm 60 you still learn an get surprised in stereo audio gear land.

 

[KozmoNaut]

A lot of engines use resonance in the airbox and plenum as a passive supercharging effect. So the comparison to bass reflex is actually not that off ;-)

 

[q3cpma]

Not really. Nobody is stuffing air into the box. Superchargers are of limited use due to fuel efficiency concerns. I suppose you could say a turbo gets more power per liter of engine than atmospheric and that ports get more bass per liter of enclosure, but it just kind of rhymes.

You didn't get it, mate. It's turbo lag (port tuning being a bit like turbo pressure) same with the efficiency of forced induction vs the very simple design and more linear power output of the atmospheric; we can forget superchargers in this analogy, just wondered where they'd fall, since they don't have the lag but are not as efficient as turbos.
Not that it's important, the car analogy just seemed right to me.

 

[Juhazi]

A 2-stroke power pipe is analogical too. They are tuned to specific rpm range which is art and science!
https://en.wikipedia.org/wiki/Expansion_chamber

Boat racing engines have adjustable length!