Hi ! i am here after coming to a very important conclusion
The subwoofer duty is the most challenging application for a cabinet (too trivial ? 😉)
Let me elaborate a little first
Above a certain frequency the vibrations level is so low that taming them is not a big issue
I would fix the cut at about 200Hz more or less
For this reason my ideal speaker has the bass box separated by the other drivers
The range up to 200Hz is very well within the limits of any kind of sub even the biggest ones And that is what i would like to do in the future
A satellite dealing with the range from 200Hz up above a sub with some kind of mechanical decoupling
This said i would like to hear what kind of test do you perform on your subwoofer cabinets
In particular my main interest is to understand what kind of measurements could provide the most reliable information about the quality of the design and construction of a cabinet for a subwoofer
I mean you can brace and add mass to the cabinet
But how do you know when the cabinet is well done ?
Then i would like to suggest a very weird test to get an idea of the vibrations of a cabinet side
Just stick with some biadesive tape a small piece of mirror on the side and direct a laser beam on it from an angle
The movements of the mirrored point will provide a measure of the vibration of the cabinet side
In the ideal case the point should stay steady without any kind of oscillations
Of course the front baffle is the most critical side As always for speakers in general
Thank you very much indeed
Kind regards, gino
The subwoofer duty is the most challenging application for a cabinet (too trivial ? 😉)
Let me elaborate a little first
Above a certain frequency the vibrations level is so low that taming them is not a big issue
I would fix the cut at about 200Hz more or less
For this reason my ideal speaker has the bass box separated by the other drivers
The range up to 200Hz is very well within the limits of any kind of sub even the biggest ones And that is what i would like to do in the future
A satellite dealing with the range from 200Hz up above a sub with some kind of mechanical decoupling
This said i would like to hear what kind of test do you perform on your subwoofer cabinets
In particular my main interest is to understand what kind of measurements could provide the most reliable information about the quality of the design and construction of a cabinet for a subwoofer
I mean you can brace and add mass to the cabinet
But how do you know when the cabinet is well done ?
Then i would like to suggest a very weird test to get an idea of the vibrations of a cabinet side
Just stick with some biadesive tape a small piece of mirror on the side and direct a laser beam on it from an angle
The movements of the mirrored point will provide a measure of the vibration of the cabinet side
In the ideal case the point should stay steady without any kind of oscillations
Of course the front baffle is the most critical side As always for speakers in general
Thank you very much indeed
Kind regards, gino
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Subwoofers are the easiest cabinets to do (particularily if sealed). Use push-push (force cancelation) and build a light very rigid box with any potential resonances well above the bandwidth of the woofer.
My first tool for a subwoofer (or any other enclosure) is a mecjhnics stethescope which very quickly detects potential resonances.
Acoustic measurement is a case of you are really measuring the room.
dave
My first tool for a subwoofer (or any other enclosure) is a mecjhnics stethescope which very quickly detects potential resonances.
Acoustic measurement is a case of you are really measuring the room.
dave
https://www.diyaudio.com/community/...od-internal-painting-etc.413216/#post-7693948
FWIW/YMMV, etc., I used a square edged coin perched on edge and swept a sine wave of LF from 20-500 Hz and as long as it didn't fall over I was good 'enough', all things considered.
FWIW/YMMV, etc., I used a square edged coin perched on edge and swept a sine wave of LF from 20-500 Hz and as long as it didn't fall over I was good 'enough', all things considered.
Hi and thank you very much indeed for your kind and very valuable advice
I have seen the approach you recommend and i agree completely But this will mean 4 woofers instead of 2
I have to say that looking around most subs come with just one woofer
I understand that their design and construction will be more challenging but this is what i would prefer
Very good woofers are very very expensive Moreover i could find a pair 2nd hand ... 4 is almost impossible
Very interesting and thank you Let me tell you an experiment we did with a friend
We took a 2 ways bookshelf with a 8" woofer and glued some lead sheets to the internal side of the panels
Then we used a pipe organ track with a very full range sound
We were shocked by the difference in sound with the unmodded speakers
This was one of the experience that change completely the perspective For one thing i understood how big is the role played by the cabinet in the sound coming from a speaker
This could be not so evident with limited range instruments like flutes triangle etc.
But with full range instruments like pipe organ and piano .... wow Sincerely amazing
this is the critical part I can act on system much more easily than on the room That is my never solved primary issue
I am completely sure that putting a panel or a tube trap here and there would be like a patch ... a band-aid
The room is the first thing
The evidence is by seeing how much recording studios spend for the acoustic treatement of the recording room
Hi ! thank you very much Mr GM for the very valuable advice and link
I will study that long thread with the most interest before asking more questions
Unfortunately and please excuse me i did not find it first Better late than never
Thank you very much again
I will study that long thread with the most interest before asking more questions
Unfortunately and please excuse me i did not find it first Better late than never
Thank you very much again
Hi ! yes that is very good and easy
I am going a little of topic but another easy and very cheap tool to check for the cabinet tendency to resonate is this one
one usual mistake done is to consider the speaker like the body of an acoustic instrument This is very wrong imho
An acoustic instrument body is designed and built to resonate to amplify the vibrations generated by the strings
A loudspeaker must be as passive as possible It should not amplify anything Just reproduce the incoming electric signal
I have bought one of the mechanism above It is impressive and sad how its weak sound is amplified by some speakers cabinet
And it works fine also with different materials to check their acoustic resonance
I put it on lead sheet Dead Almost no sound coming out
Even amplifiers cabinets resonate ... and if the transformer vibrates ...
Key to this design is the woofer magnet braced against 3 panels +nthe brace.
To keep the price down and what people expect. The better ones are push-push and some not too pricey (the little KEF cube for instance)
There are tons of woofers to choose from. From dirt cheap to real dear.
Really just woofers but do a quite good job. 4 woofers about $100.
https://www.diyaudio.com/community/threads/silver-flute-w14-woofers.396686/
Usually counter productive.
dave
thank you very much and serious looking design indeed Impressive
I have only one mandatory requirements for my best speaker The woofer separated from the other drivers
The design and built of the cabinet is really the biggest challenge
Above that (i.e. above 200Hx) any decent 2 ways can work But the bass is very challenging
I do not like tower speakers at all I like MTM sats like center channels for L and R duties
Why do you say that lead cannot be useful ? after "leading" the cabinets i heard for the first time a real pipe organ piano and contrabass from my speakers
And moreover the sound came out more from the speakers
I added about 20 lbs per speaker Dynaudio msp 110
i intend to replace the Qts=1 woofers with something smaller but better Like a good 7" for instance
High Qts means too high moving mass and to weak magnet Slow to move and slow to stop Sluggish
But the lead had a nice effect indeed But it is toxic
I have only one mandatory requirements for my best speaker The woofer separated from the other drivers
The design and built of the cabinet is really the biggest challenge
Above that (i.e. above 200Hx) any decent 2 ways can work But the bass is very challenging
I do not like tower speakers at all I like MTM sats like center channels for L and R duties
Why do you say that lead cannot be useful ? after "leading" the cabinets i heard for the first time a real pipe organ piano and contrabass from my speakers
And moreover the sound came out more from the speakers
I added about 20 lbs per speaker Dynaudio msp 110
i intend to replace the Qts=1 woofers with something smaller but better Like a good 7" for instance
High Qts means too high moving mass and to weak magnet Slow to move and slow to stop Sluggish
But the lead had a nice effect indeed But it is toxic
Adding mass to the cabinet walls without increasing stiffness pushes resonances down (not a good idea at all in a subwoofer) and decreasing their Q, both which tend to make resonances more audible.
Now if you are doing amidrange cabinet it might work if you can push the resonancesdown well below the drivers bandwidth.
This almost worked in the LS3/5A, not so well in boxes that go lower.
dave
Hi another nice case of bracing here
The middle stiffener it's placed just above the woofer
Again it's not my favourite solution
I will keep the woofers separated physically from mids and highs in a head box with little lead on the panel as per you recommendation
They will be perfect
The middle stiffener it's placed just above the woofer
Again it's not my favourite solution
I will keep the woofers separated physically from mids and highs in a head box with little lead on the panel as per you recommendation
They will be perfect
Hi what do you mean?
I forgot to mention that I don't like woofers mounted on open baffles
I understand they are trying to mimic big panel speakers that also I don't like
I like pin point sound image with a granitic presence of instruments and players
Panels or omnis can't do that
My reference speaker could be the Wilson Audio Watt plus Puppy
On cheap
I forgot to mention that I don't like woofers mounted on open baffles
I understand they are trying to mimic big panel speakers that also I don't like
I like pin point sound image with a granitic presence of instruments and players
Panels or omnis can't do that
My reference speaker could be the Wilson Audio Watt plus Puppy
On cheap
The lightness is useful for raising the cabinet wall resonant frequency. But this doesn't mean weight can't be added elsewhere, like screwing down to a marble or concrete slab for instance. Or a masonry floor if you have one.
The most elegant answer is probably the dual opposed (push push) configuration to reduce overall box vibration to begin with, either alone or in combo with a heavy base. But double drivers cost more and sometimes aren't practical. The cabinet walking is also different and audibly less important IMO than its panels resonating within the intended frequency range. So I think a heavy base is a fair and easy compromise.
The most elegant answer is probably the dual opposed (push push) configuration to reduce overall box vibration to begin with, either alone or in combo with a heavy base. But double drivers cost more and sometimes aren't practical. The cabinet walking is also different and audibly less important IMO than its panels resonating within the intended frequency range. So I think a heavy base is a fair and easy compromise.
They are making a common “mistake" orienting thre sole brace that way. More effective if the brace runs vertically, Rule/guidline 1of bracing: the aspect ratios of the subpanels created by the brace should be greater than the aspect ratio of the panel being braced. One wants to push resonces as far ups as possible. Corollary: the 2 sub panels should not have the same aspect ratio.
I would put 2 braces (crossed) in that box. And i would use the main brace to connet the driver to 4 panels.
dave
hi thank you very interesting But what about placing a heavy slab above the cabinet instead ?
i have seen people using heavy doorstops above the speakers
of course a great cabinet will need nothing But the great cabinets are usually found in very expensive speakers
Cover a ls3/5a with lead sheet
Which thickness, which glue, how to hold it firmly
Disclose them all, and report
... the woofer is back mounted ah ah ah!