I would define a speaker (an entire system) as a combination of frequency regions, some of which are minimum phase and some of which are not.
The minimum phase regions are where flat phase and flat group delay (accompanies the presumed flat frequency magnitude response.)
The non-min phase regions are IIR crossover regions with their phase rotations and variable group delay.
Which is what I've been saying..
I've found a good FIR generator can correct an entire speaker's response, to be essentially perfectly flat across the spectrum, both mag and phase..
To a particular point in space....on-axis.
If the entire speaker were minimum phase, off-axis rotations should only show variations based on changing geometric distances to acoustic centers.
Which I've found tends to hold true for the regions that had flat mag and phase (the min-phase regions) before the global FIR correction.
But the FIR corrected crossover regions don't behave nearly as well off-axis.
Which means to me....ditch the idea a speaker is predominantly min phase. Cause seems it just ain't so.
And hey, i really dislike pedantic debates. All i care about is good communication, aimed at understanding pragmatic reality.
Personally, I've come to believe min phase EQ's on truly min phase devices/systems are the only really valid forms of correction.
So it's been important for me to know exactly what is, and what isn't min-phase.
that's 99% of the debates on this forum
Sorry to bring it so cynical, but what I mean by that is that the vast majority is not discussed around that pragmatic reality, but rather blowing up small bits that are just NOT THAT relevant in a practical design.
Sure, they can be an important small part of the puzzle, but certain other bits are far more significant.
A good example is a project I'm currently working on for a client.
The "technical bits" were quickly settled and just need some little tweaking and tuning.
However, the practical side is a totally different animal.
We recently had to change the active electronics, just because we simply couldn't fit it in the cabinet and also please the visual design team.
Still having an hard time getting it all fixed, especially because it also has to be ready and easy for production and assembly.
Certain pedantic debates can be useful, but more just as an exercise or just to get definitions straight and understood. Especially when they are misused. Which seem to happen quite a bit unfortunately.
IMO, an interesting experiment would be to compare a ported system to such a sealed system that is equalized to the same frequency response as the ported have. Mathematically they would exhibit the same decay but in reality, the result would maybe different and there is a possibility that the ported would show better decay in some way.
The ported system is obviously much harder to equalize to the same frequency response as the sealed have, because of the port unloading below the tuning frequency.
Could you guys comment on this stacked fullrange, in principle or concept, with respect to this discussion of so-called minimum phase and linearity?
https://www.diyaudio.com/community/threads/full-range-speaker-photo-gallery.65061/post-7675238
I had posted it over there because it used only fullrange drivers without crossover, though obviously a 2-way (there being no suitable multi-way gallery). While I cannot produce graphical and more technical measurements due to not having a "man-cave" setup that can be left overnight on weekdays -- I have done this "design and test by ear" dozens of times (since covid) to be reasonably confident of my method, simple as it is. (I have a Radio Shack sound meter too but not the space to use it for bass.)
BTW the micor55 "LX" in cabs cost me about 900 renminbi or $130 ;-) Over the range upper-bass to mid-treble (ears too old to judge directly above 12.5khz) easily the most realistic and detailed I've heard to-date.
https://www.diyaudio.com/community/threads/full-range-speaker-photo-gallery.65061/post-7675238
I had posted it over there because it used only fullrange drivers without crossover, though obviously a 2-way (there being no suitable multi-way gallery). While I cannot produce graphical and more technical measurements due to not having a "man-cave" setup that can be left overnight on weekdays -- I have done this "design and test by ear" dozens of times (since covid) to be reasonably confident of my method, simple as it is. (I have a Radio Shack sound meter too but not the space to use it for bass.)
BTW the micor55 "LX" in cabs cost me about 900 renminbi or $130 ;-) Over the range upper-bass to mid-treble (ears too old to judge directly above 12.5khz) easily the most realistic and detailed I've heard to-date.
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That is not hard to do with a sealed system.
Fact is that you will find a very different set of limitations.
Naturally the driver in a sealed system will have an higher cone excursion.
Limiting the total SPL output potentially and adding a lot of additional linear and non-linear distortion.
Yet, at the same time a ported system has less of this problem, but more issues around the port itself.
On top of that often a very difficult port resonance (around 500-1500Hz).
Also, even in an active system, a ported system often needs more volume.
Which can lead to port length etc etc etc
So practically speaking, there are always compromises.
To some extend talking about "what is best" is a good example of a very pedantic approach to this discussion.
ALL systems have pros and cons, advantages and disadvantages.
If someone things one system is "superior" then the other, than there is a lot of unfamiliarity going on.
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Just because people like or need to see the visuals;
Just an arbitrary random driver (because it's the first in my database), and certain volume for no particular reason.
Both at the same sound pressure level (exact value not relevant)
Right of the bat, you already see a couple of these practical limitations.
They have exactly the same system response, therefor same group delay.
The cone excursion for the closed system is significantly higher.
Also the apparent power is higher (not shown here)
In this case the system response was fitted to the ported system.
So in reality we can probably have a "better" system response.
Meaning a less steep curve (lower f12 point) while maintaining roughly the same peak cone excursion.
Which also results in a better group delay (if that is your thing)
While the ported system has a 32cm long port with a resonance around roughly 530Hz
Not only that but it also adds an additional 0.58 liter to the system, that you have to compensate for in the cabinet dimensions somehow.
Not to mention the practical issues to try to fit a 32cm long port with a Sd of 18cm² (which is even on the small side) somewhere as well.
So yeah, pick your evil....
Just an arbitrary random driver (because it's the first in my database), and certain volume for no particular reason.
Both at the same sound pressure level (exact value not relevant)
Right of the bat, you already see a couple of these practical limitations.
They have exactly the same system response, therefor same group delay.
The cone excursion for the closed system is significantly higher.
Also the apparent power is higher (not shown here)
In this case the system response was fitted to the ported system.
So in reality we can probably have a "better" system response.
Meaning a less steep curve (lower f12 point) while maintaining roughly the same peak cone excursion.
Which also results in a better group delay (if that is your thing)
While the ported system has a 32cm long port with a resonance around roughly 530Hz
Not only that but it also adds an additional 0.58 liter to the system, that you have to compensate for in the cabinet dimensions somehow.
Not to mention the practical issues to try to fit a 32cm long port with a Sd of 18cm² (which is even on the small side) somewhere as well.
So yeah, pick your evil....
I've done that, using the same driver. With about the same internal volume net of port volume.
Eq'ed the sealed's mag response to match the ported...which made phase response match well too.
I used a frequency & level dependent limiter, below port tuning frequency, so that until SPL was high, the ported did not have an electrical high-pass in place.
(And still have essential protection from port unloading, which I see as mandatory)
At low to moderate SPL , they measured and sounded close enough I couldn't tell a difference.
When cranked up, and the sealed started crapping out with any frequency content near port tuning frequency......(where the sealed had to have substantial boost)
I think economics is really the only reason why sealed woofers seem to be out of fashion. It's simply cheaper to get to an SPL target that way. That is almost an over-riding consideration in the commercial world. You need the extra headroom of vented given the narrow enclosures that dominate there.
If you don't care about the extra cost. you can add a 2nd woofer and EQ in the same box volume and get the same SPL (enough for home use) with better dynamics/transient response, no vent turbulence or vent pipe resonance to deal with and you can be reasonably certain you will get the response correct with EQ in the first prototype.
If you are only a little bit clever, you can place the 2nd woofer (for a 3 way) in a vibration cancelling orientation.
If you don't care about the extra cost. you can add a 2nd woofer and EQ in the same box volume and get the same SPL (enough for home use) with better dynamics/transient response, no vent turbulence or vent pipe resonance to deal with and you can be reasonably certain you will get the response correct with EQ in the first prototype.
If you are only a little bit clever, you can place the 2nd woofer (for a 3 way) in a vibration cancelling orientation.
Agree with most all of this, and about economics dominating, too.
What prevents me from doing the "double up on sealed" in the same size box though, is I've come to really prefer the sub cones face me.
I think they provide a better 'transient wave vector' or something, for lack of good terminology. I simply can't agree with the subs are omni line of thought, when it comes to bass transients.
So force cancellation doesn't work, as it doesn't let two drivers face me.
And getting two drivers to face me, makes the box get even bigger than a single driver ported.
For me and what I like, I see the economics as much about size, as cost.
I like sealed speakers and subwoofers they blend almost perfect on the crossover point.
Arendal speakers are sealed or designd to use sealed with port plugs, the only reason to remove the plug is when you dont have subwoofers.
For diy sealed subwoofers are also simple to make.
Arendal speakers are sealed or designd to use sealed with port plugs, the only reason to remove the plug is when you dont have subwoofers.
For diy sealed subwoofers are also simple to make.
Your brains are playing with your ears I guess
It's not about the ears. It's about the tactile sensations of the body. The hit in the chest, etc.
There's no question ime, that cones directly facing the listener impart more tactile hit/punch than other arrangements.
Plus, there's the empty beer can test, if you can get past the idea of no brain-bias.
Put one on a table in front of various type subs, and see which of the subs can blow the can off the table...and then at various distances.
For a source that is omnidirectional, this makes even less sense.
The tactile feeling comes from the pressure waves, which is directly proportional to the SPL.
Unless you have enormous cabinets, but at these huge wavelengths, the cabinet is non-existing.
From a personal subjective point of view, I also don't share the same experience.
But, fair enough, let's do a blind AB and ABX test and we'll know for sure 😉