This is factually not true as a general statement without more context.
When you pick something that is bigger than 12-15 inch, that is pretty much dead on.
Anything smaller and one definitely has to consider some things.
The Fs will determine were the woofer will become heavily non-linear.
Below the Fs the compliance will be the dominant factor, which will be very non-linear for a lot of smaller drivers.
The Q-factor will become relevant for how much the system has to be corrected and therefor the total system power. Obviously cone excursion is also a factor here.
This is all idealized of-course, one has to look at the data to figure out what suits best.
Compromises have to be made.
Although technically this is also true for bigger (sub)woofers, in practice you probably won't get there because they will create serious SPLs. Very different story for sound-reinforcement applications and such.
But yeah, if you want a home system without compromises, just shove a bunch of 15-18 inch subs in the corners and call it quits. The distortion numbers for even "heavy" home use are basically non existing.
Fun fact, most of the time they are a lot cheaper than most smaller "hifi" subwoofers.
Inter-modulation distortion is likely also to be a lot less because there is less excursion.
Just for the sake of being clean and perfect, I always advice to get at least one that has a Fs lower than 40-45Hz as well a 6mm xmax or so. So you have some leverage in tweaking and tuning.
Some earlier posts from Earl in this thread that provide some context
https://www.diyaudio.com/community/...w-distortion-with-a-2-way.334757/post-6761795
https://www.diyaudio.com/community/...w-distortion-with-a-2-way.334757/post-6717806
That is only from the context of the room, not the context of system design.
Unless you want to blow up your 6 - 10 inch subwoofer in an instance or listen to a bunch of audible distortion (no, I don't mean the nit-picky kind), go ahead.
However, context still can't be known from the post above, the one I responded to.
People might as well read it as it never is important, which is not true.
As for 15 inch woofers, I would also not recommend getting a (guitar) speaker with a Fs of 80Hz en a Qt of over 1 and a huge Vas. Even if it would have enough cone excursion, that's not really gonna work well.
Even less so when someone tries to squeeze that into a 35 liter cabinet.
That is obviously a bit of an extreme example, but from a system design point of view, it's always advisable to see what what to expect. And yes I have seen people (and even clients) picking up such (absolute) statements and go along with it.
Wondering why it sounds so horrible or why they keep blowing up stuff.
I don't think that I misunderstand energy storage and I don't understand what this comment has to do with my statements.
Yes, I discount virtually all subjective tests not done scientifically and I'll stand by my statements that there is nothing that you can hear that can't be measured. It just has to be put into quantitative terms and not just "I can hear ...".
If you are referring to nonlinear distortion then I have never said that it is never an issue. It often is an issue, unfortunately. But since it can be designed to be inaudible, I don't see any point in not doing so. I don't deal with "broken" systems, only ones that are well designed. In that case it is not important.
I understand your context, but readers can not see if you only ever deal with "well designed" systems or if it was said as a general statement. Which is a very important nuance.
Using and EQ'ing a woofer with a relatively high Qt as well as a high Vas in a small cabinet also creates all kinds of issues when it comes down to power. Again not an issue with a proper 15 inch pro subwoofer.
But again that context was missing.
Terms like well designed and professional are not quantified and are subjective.
So it's kind of vague without giving numbers or more context.
I'm pretty sure Earl considers the room a part of the system, I do too because I am only making things for me.
That isn't what I take from his words, in fact the opposite, concentrate on Volume Displacement to meet the design goals.
Indeed but this is a long thread where much has been said by many, sometimes a message gets repeated shortened. I tried to provide some of the context with links to show that there was more said before than just the few words you quoted.
Unfortunately, many scientists still confuse science with truth, when science in the strict (unspoiled) sense is really just a toolbox, not a religion.
IOW don't fall into the "I can't see (measure) it, so it doesn't exist" trap.
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That's an extreme example, but I hope you agree that some general purpose/instrument woofers make excellent midwoofers.
And I'd say: the less excursion, the better.
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Fully randomized double blind studies in psychoacoustics are notoriously hard to fund and tough to set up, party because they are multidisciplinary and (perhaps with the exception of speech recognition and some building acoustics) still are considered somewhat esoteric and require a lot of resources. Music reproduction in speakers is obviously an even smaller subset of this.
The goal of psychoacoustics is how we perceive and understand sound, if we can measure everything we can hear is one thing (I don’t fully grasp how can this statement could be scientifically verified, but this is your opinion and I respect that) but let’s say we do; we still need to understand how people process and interact with sound.
Measurements give us data and psychoacoustics is the scientific research on the meaning of the data to give us information.
@gedlee As an academic I’m sure you are eminently aware of all this, the above is for context and perspective only.
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All these issues regarding complexity of DBT etc seem to be based on the premise that people actually do hear differences.
Over the years I have formed the dissenting opinion (no, not a conclusion!) listeners in audio image all sorts of things and claim to hear al sorts of differences between equipment, in particular in sighted situations. Over all these years of subjectivism, there is still relatively little evidence the claims of the subjectivists can be substantiated.
To make a provokative statement: put two highly acclaimed amplifiers in different housings, one in the original housing, the other in an el cheapo receiver housing and your audience will no doubt claim to hear substantial differences. For loudspeakers there is little that is not known.
So I am completely with Earl on this one.
Over the years I have formed the dissenting opinion (no, not a conclusion!) listeners in audio image all sorts of things and claim to hear al sorts of differences between equipment, in particular in sighted situations. Over all these years of subjectivism, there is still relatively little evidence the claims of the subjectivists can be substantiated.
To make a provokative statement: put two highly acclaimed amplifiers in different housings, one in the original housing, the other in an el cheapo receiver housing and your audience will no doubt claim to hear substantial differences. For loudspeakers there is little that is not known.
So I am completely with Earl on this one.
My post was done explicitly to avoid those kind of comments. Bias and preference/placebo was proved many decades ago in psych research looking at the effects of wrapping in the perceived taste of margarine. It’s fully understood and undisputed that we actually cannot discern and sort positive bias between taste and visual appearance f.i.
Once again, I am not talking about Earl himself, I am talking how a certain statement can be misinterpreted by readers.
Well that's a bit of inside the box thinking.
There are plenty of listening and loudspeaker gatherings.
Often for hobbyists, but quite some professionals and academics also join in with those events.
On average you will find at least like 20-30 people, which is quite a nice group very any research project.
The majority of those people are often skilled listeners, involved in audio and/or musicians, which is an extra bonus.
With some planning in advance there is absolutely nothing to stop you to do some proper double blind tests.
It basically requires zero funding or very little at least.
It sometimes feels like academics seem to be only living in their world of academics.
You will be surprised how far you will get with a bit of creativity and creative thinking.
You will also be surprised that there quite some VERY smart people walking around just in hobby scene.
Some with not even a scientific background, yet building and developing speakers that outperform many commercial speakers (made sometimes by academics) with ease.
Another note about measuring, knowing and information.
We can flip the question and probably already answer with some thought experiments.
So instead of measuring everything and making sense of all the measurements, we can ask the question "What information do we need from our perception point of view?" . And start to fill in the information and gaps accordingly that way.
Also, a lot of stuff can already been ruled out with some deductive logic and reasoning.
Something that seems to be often totally omitted in the field of audio and acoustics.
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Please note the first two words I wrote “fully randomized”. These tests should be utilizing random selection among the population in order generalize the results to a larger group. Pretty much the opposite of what you outlined.
I know the audio world keeps forgetting random assignment in double blind testing but this is crucial when testing humans.
I know the audio world keeps forgetting random assignment in double blind testing but this is crucial when testing humans.
Did I just mentioned deductive logic and reasoning?
There is nothing wrong with having a certain bias, as long as you keep the bias in mind.
So a test can be done with super highly skilled listener experts.
Lets say that they even can't hear the difference in a certain experiment.
That automatically (by factual definition of deduction) means that on average, people are not able to hear it as well.
Probably (very likely) even less so.
Fully randomized is by definition not possible btw, that's the reason why we need to use things like SD and SEM
So a bias is by definition inevitable, because fully random is only possible with an infinite amount of test subjects (people).
As long as you keep the bias in mind, and write your conclusion accordingly, there is nothing wrong with it.
These techniques are being used in other fields of physics, biology and archeology all the time.
In the world of audio they just keep being pedantic about certain things.
It's also kind of ironic, because the very vast majority of hundreds of papers I have read (incl Toole's for example), the experiments were done with just an handful of test subjects, often not more than 5-10, and just only done by the academics or a couple of students that were on hand. So very very far from being random.
Yet, it gives us enough insight to get an order of magnitude at least.
Which is in most cases already more than enough to determine how meaningful it is in the whole chain of variables.
Weirdly enough some people don't seem to understand the definition of "order of magnitude" and still try to squeeze out more and more decimals. As if that is going to give any significant improvements.
A good example of this is distortion (THD+N).
edit: Forget to add. But there is also nothing wrong with the first initial tests not being totally random.
Once again, it will give enough insight to see in what order of magnitude we are talking about.
If the results seems to be interesting enough, a follow up can always be organized to get the results a little bit more objective.
Another idea is first to estimate how much more "experts" will be compared to totally random people.
Once you get some numbers from there results can always be adjusted accordingly.
That still won't give perfectly random results, but you will get at least better results.
Again, when the outcome looks promising, a follow up can always be organized.
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The mere fact that a lot of papers are written on the basis of a smallish non random sample exactly goes to my point.
Their value IS LIMITED because results cannot be extrapolated uniformly to a much larger population.
My criticism is therefore based on the fundamental limitations of the statistical model. This is what it is.
Questioning results and evidence based criticism is, after all, what science is about.
As you no doubt remember, Toole points out the 'experts' where frequently wrong and performed significantly worse in double blind testing than random students picked for the tests.
I was trying to make a clear point which I never anticipated would be contentious, my apologies for the OT.
Their value IS LIMITED because results cannot be extrapolated uniformly to a much larger population.
My criticism is therefore based on the fundamental limitations of the statistical model. This is what it is.
Questioning results and evidence based criticism is, after all, what science is about.
As you no doubt remember, Toole points out the 'experts' where frequently wrong and performed significantly worse in double blind testing than random students picked for the tests.
I was trying to make a clear point which I never anticipated would be contentious, my apologies for the OT.
My poor house wasn't ready for the assault when i fired that big stack up ! Lol'Humble' home entertainment.
All those boxes were my first DIY builds of my own design...when i was trying to partner with a local live-sound guy.
I was going to rent speakers, amps, and processing for gigs when he didn't have enough PA.
Alas, idea/partnership fell through...never even got to hear that stack at a gig.
The three sections of main columns as shown, had 140 deg horiz coverage, and probably needed 3-4 labhorn subs to match their output.
Except you put the vents on the front not the side
yep. The 40 degree trap angle for the horn cabinets was determined by how the 60 degree XT1464 horns splayed together for even coverage.The cone cabinets had to match that angle, and tight pack the same.
So each vertical stack added 40 deg H, and if I had enough, 9 stacks would make a full circular array.
4 stacks was all I built when PA aspirations fell apart.
On a complete tangent...at Smaart training classes, various cardioid sub setups are made, where we could measure and walk/listen all around them.
It was pretty clear that cardioid is no completely free lunch, and comes at a price to the forward sub sound. Good ole audio tradeoffs, huh?
Hi Charles, the top two were both 18sound, the XR1464C 60x40, and the XR1496C 90x60.
They were the horns used in the two versions of JTR's 3TX. They sounded very good in the 3TX, but i never really got the chance to compare them much apples to apples, in singular stacks of the modular setup I built.
I can say the XR1464C's 60 deg horiz pattern, didn't seem to have as sharp a -6dB edge, as the 60 deg XT1464 has.
Can also say if I wanted to use a single stack of the modulars for 90 coverage, I'd likely go with the RCF 950, just from positive experiences with it in the PM90s.