Hi Ginetto,
I posted the update of my speaker.
There are pictures of the bass cabinet bracing, maybe you find some ideas.
I posted the update of my speaker.
There are pictures of the bass cabinet bracing, maybe you find some ideas.
Hi, Gino!
I'm just an amateur and this thread is not only very interesting, but it has prompted others to post even more interesting things.
That said, in my own little way I've experienced that coupling or decoupling "sounding objects" do not always have a predictable effect on their resulting SQ.
There are so many people in this thread who express high levels of knowledge and design and construction and it is very informative to read and learn, so I say this with the greatest possible modesty, but I guess there is not a mathematical model relating to vibrations that suggests how a speaker will sound if it is coupled or decoupled from the surface on which it rests.
Maybe a lot also depends on the weight of the object (cabinet), and perhaps (perhaps) the heavier a cabinet is the more it "should" be coupled rather than decoupled from the surface on which it rests, but I believe that only listening to it can provide useful indications in this regard.
Of course, I completely agree with the fact that theoretically the less vibrations are transmitted the better the sound quality result "should" be, but maybe that is not always the case.
In my (very) modest view.
Hi thank you very much for your kind and valuable advice
I have even seen some speakers where the head speaker is placed on a column/ stand completely separated from the bass box
If i have learned one thing is that the cabinet for the bass must have properties completely different from those of the cabinet for the mid high
The bass box must be stiff to move resonance up
The mid high box must be heavy to move resonance down
If you have all drivers in the same box and it's rigid the resonance from the woofer will mix with the mid and tweeter emission
In a word a real mess
I have even seen some speakers where the head speaker is placed on a column/ stand completely separated from the bass box
If i have learned one thing is that the cabinet for the bass must have properties completely different from those of the cabinet for the mid high
The bass box must be stiff to move resonance up
The mid high box must be heavy to move resonance down
If you have all drivers in the same box and it's rigid the resonance from the woofer will mix with the mid and tweeter emission
In a word a real mess
Backmoin the ‘80s i was exposed to this method of decoupling with a tweeter. PEARL PR-2.
dave
Yep, springs really work for me too: I've been using them under almost all pieces of audio equipment except speakers for a while now.
www.diyaudio.com/community/threads/your-contribute-to-audio-evolution.395785/post-7268708
Hi thank you for the very valuable advice
The tweeter diaphragm displacement is very small
Therefore even small vibrations coming from the baffle can have a significant impact on the tweeter emission because of the same order of diaphragm displacement during music
Clearly a massive baffle will reduce the issue
I am pretty sure that if i take a cheap 2 or 3 ways commercial speaker i extract the mid and high and i place them in a cabinet mechanically decoupled from the woofer cabinet at least the soundstage will improve but also the transparency of the mid high
The effectiveness of the decoupling should be then checked clearly
The tweeter diaphragm displacement is very small
Therefore even small vibrations coming from the baffle can have a significant impact on the tweeter emission because of the same order of diaphragm displacement during music
Clearly a massive baffle will reduce the issue
I am pretty sure that if i take a cheap 2 or 3 ways commercial speaker i extract the mid and high and i place them in a cabinet mechanically decoupled from the woofer cabinet at least the soundstage will improve but also the transparency of the mid high
The effectiveness of the decoupling should be then checked clearly
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I guess you can't know until you've tried it and listened to it. 😉
Hi yes of course
Still i guess it is the rationale behind concepts like this one below
I once read an interesting analogy
It compared the front baffle of a speaker to a newspaper page placed in front of the reader
if the page remains still it will be easier to read both the large characters (low frequencies) and the smaller ones (high frequencies)
if the page moves back and forth the large characters will still be readable maybe with difficulty
but the smaller ones will be very hard to focus
I was intrigued by this analogy
Often, visual characteristics such as transparency are used to describe the auditory experience
there is a kind of link
Still i guess it is the rationale behind concepts like this one below
I once read an interesting analogy
It compared the front baffle of a speaker to a newspaper page placed in front of the reader
if the page remains still it will be easier to read both the large characters (low frequencies) and the smaller ones (high frequencies)
if the page moves back and forth the large characters will still be readable maybe with difficulty
but the smaller ones will be very hard to focus
I was intrigued by this analogy
Often, visual characteristics such as transparency are used to describe the auditory experience
there is a kind of link
We were talking about decoupling before, but right now - in the case of the speakers you posted - you are talking about the reduction of the effects of the diffraction of the baffle and its edges related to high frequencies, I think they could be two different things.Still i guess it is the rationale behind concepts like this one below
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The diffraction is never an issue take a piece moquette make a hole in the middle for the tweeter and any diffraction will vanish
we can discuss about the shape and the hair lenght for the best solution
i reaaly do not understand why people keep on rounding edge when the issue can be dealt close to the tweeter
with the felt the tweeter emission will never reach the edges
found this
and for the mid too in the three and more ways
Maybe i have become so obsessed with decoupling that i see decoupling everywhere
we can discuss about the shape and the hair lenght for the best solution
i reaaly do not understand why people keep on rounding edge when the issue can be dealt close to the tweeter
with the felt the tweeter emission will never reach the edges
found this
Bowers & Wilkins mount their tweeter assembly above the cabinet - supposedly it's more acoustically decoupled and cleaner in its solid enclosure. See pic below.
Are there any benefits to mounting a tweeter above the cabinet in a similar way, like in a heavy aluminium tube? The main cabinet for a 2-way could have the mid-bass mounted right at the top so as to be as close to the tweeter as possible.
One benefit would be that you could easily swap tweeters when experimenting.
Are there any benefits to mounting a tweeter above the cabinet in a similar way, like in a heavy aluminium tube? The main cabinet for a 2-way could have the mid-bass mounted right at the top so as to be as close to the tweeter as possible.
One benefit would be that you could easily swap tweeters when experimenting.
anyway i did not find the B&W official motivation for this design choice
and for the mid too in the three and more ways
Maybe i have become so obsessed with decoupling that i see decoupling everywhere
This is better than ALL the springs, platforms, spikes bla bla. If you want a standard to compare the other approaches ...
But I don't think it is a real problem if the bass box is sitting on the floor properly
Maybe because our personal beliefs, and I've some of them of course, are not always supported by scientific evidence.
I think it's okay to have our own personal beliefs, but maybe scientific evidence is also quite important.
I'm not saying it does contain the proof we were looking for, but maybe this is of interest too.
www.diyaudio.com/community/threads/what-do-roundovers-do.303155/
Good morning clearly the solution of the head on top is so convenient that justifies some testing with different decoupling options
But there is point always related to the bass box that torments me after watching this video
and this ratio is said to be very very high to avoid any vibration of the box
My feeling is that the statement is very right but being ignorant in physics i am really confused and not 100% sure
for example is it just a question of cone mass or also of diameter? i.e. does it change anything if i have two woofers one 8" and one 15" but with the same mass of the cone?
i understand the concept of reaction forces and i understand perfectly that two woofers mounted back to back compensate for these forces making the construction of the box simplified
but i would really prefer the solution with a single front woofer
since it has practically always been the norm and can be found on excellent sounding speakers
Absolutely Maybe i have already said this but if if I had been good at math I would have definitely studied physics and spent my life in the lab doing tests
When i read something like this i understand the power of math
is there anything more to say ?
i agree completely that a deep understanding of the laws of Physics is mandatory to design anything Even a frying pan
maybe i am exaggerated the difficulty of the task but again a box for a powerful woofer imho is one of the most challenging task in speakers design
i am not completely convinced that high stiffness is enough
I think that also high mass is important expecially when just one woofer is used
Thanks again
I believe that more or less wide and thick felt stripes on the edges of the speaker should be sufficient to prevent the edges from becoming points of secondary emission like a sort of absorbent frame in short
I repeat, it is not a problem that seems so worrying to me
it is a matter of doing some tests and measuring the frequency response that without a doubt
Just to be clear, I admire your work and your modesty and even your beliefs.
Also because I behave more or less the same way too.
What I also believe is that everything matters.
Everything.
IMHO There is so much knowledge in human progress, but there is also still so much ignorance.
That's why sooner or later we come to understand the enormous importance of compromises in designing anything.
And sometimes the genius of the designer completely changes the cards on the table...
sure but always within the laws of physics 🙂👍
and sometimes these laws surprise me
for instance the fact that to counteract the forces created by the woofer in its movement the cabinet mass should be about 5000 times the moving mass of the woofer for a 50g moving mass this will mean a 250kg cabinet
immediately all the subwoofers but also speakers around look as compromised by design
and that explains the solution of using two woofers back to back in order to balance the forces
What I meant to say is that any designer can have a stroke of genius, whether or not it is within the laws of physics does not matter in this case because not only does it already appear obvious, but also because that stroke of genius could expand the current knowledge that we enclose in the word/concept "Physics".
A bit like the story of the bumblebee that breaks the laws of physics with its wings disproportionate to the size of its body.
What I mean to say is that when these kinds of current "mysteries" are solved, we will probably have to find another way to call them.
You yourself, like me and everyone else, have your own preferential inclinations.
Diffraction doesn't involve you as much as the characteristics that you want to shape at all costs in the cabinet of a woofer.
Maybe by insisting on this specific topic you too could have a stroke of genius, and use a material or a stratagem that no one has thought of before.
Honestly, I wouldn't even give too much importance to what is written or built by a few people because I believe (but it's just my personal opinion) that there is always a valid why and a good reason if in technology a certain solution to a certain problem is adopted by the majority of designers.
🙂
In a subwoofer clever engineering makes it push-push, and if the 5,000x figure is accurate, likely makes that number <500 at leas.
dave