One of my first builds was with scrap ply and block-board. I got the box where I wanted, then built again with MDF. The loss of cabinet interaction was profound, and as a kid that liked lots of bass, more than accurate bass, I was somewhat disappointed.
The knuckle wrap test said it all. A test I find very valid as a preliminary check. My knuckles down have digital readouts or rs232 connections, but like a gardener with green fingers, some people just know, and some don't.
The knuckle wrap test said it all. A test I find very valid as a preliminary check. My knuckles down have digital readouts or rs232 connections, but like a gardener with green fingers, some people just know, and some don't.
Surely time and ingenuity are to the DIYers' advantage compared with a commercial manufacturer!Harder to make the joints strong if they are not right angles. Right angles make optimum use of fasteners, and allow much easier clamping and weighting (needed to make the glue strong). It would take special custom tooling to clamp a box together if not rectangular cross section.
It really takes very little thought and/or cost to work out how to clamp non-quadrilateral/cuboid shapes...
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Hi this is the professional way to measure the effects with high precision I guess that the instruments are very expensiveYou could also use one of those devices for measuring vibration in power tools. Maybe.
However I think that also a qualitative testing/evaluation could be sufficient to get an idea of the cabinet behaviour
in a woofer box the vibrations will be only on the horizontal plane generated by the woofer moving back and forth
the cabinet will tend to move in the opposite direction of the cone clearly
a little container like a petri capsule placed on the cabinet top and half filled with water could be enough
The more the ripples on the water free surface the more the vibrations from the cabinet Better to stick the capsule to the cabinet with some biadhesive tape
moreover i wonder if the knock test can be useful to differentiate the various materials even before cutting them
In the video about Wilson Audio the test is carried out on pieces of the various composite
A wood with a higher pitch could be more rigid than a wood with a lower pitch
A lower pitch could mean a better vibrations damping ability of the material
I remember the pitch of a slab of lead hit with a hammer Nothing No sound Only a dead thud
The very best damping material in the world imho
if only it were not so toxic
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Shot mixed in silicone is something I have not seen for a while. It's pretty dead sounding.
Composite's seem missing to. MDF inside, chip outside, was the one iirc. However chip is so delicate, nobody uses it much at all for cabinetry.
Applying a little logic, the MDF is rigid but rings. The chip flexes, but doesn't ring.
You can't put the chip inside, as too much energy still reaches the MDF, as chip is bendy, and the MDF can add harmonics it's so stiff. It must be MDF inside, and the chip outside. As a dampening covering.
This wouldn't be waterproof chip, with it's huge resin percentage. This would be cheap chip, ready to fall to bits.
It's fell from flavour. Today we have braces that connect with a depth of sealant, to give the energy some place to go. Dampening panels without shifting the frequency up.
Composite's seem missing to. MDF inside, chip outside, was the one iirc. However chip is so delicate, nobody uses it much at all for cabinetry.
Applying a little logic, the MDF is rigid but rings. The chip flexes, but doesn't ring.
You can't put the chip inside, as too much energy still reaches the MDF, as chip is bendy, and the MDF can add harmonics it's so stiff. It must be MDF inside, and the chip outside. As a dampening covering.
This wouldn't be waterproof chip, with it's huge resin percentage. This would be cheap chip, ready to fall to bits.
It's fell from flavour. Today we have braces that connect with a depth of sealant, to give the energy some place to go. Dampening panels without shifting the frequency up.
The sound of death! 😱pretty dead sounding
For a bass box i remain on my idea A steel cage very rigid structure that can be loaded with additional weights bolted to the structure in some ways
Bass box must be very very heavy Like 50 kg
The side top and back panels can be made of different material like mdf even not very thick and kept attached with magnets to the metal frame above mentioned
This would make the access to the internals very easy
Only the front baffle should be very rigid and bolted to the metal frame
Bass box must be very very heavy Like 50 kg
The side top and back panels can be made of different material like mdf even not very thick and kept attached with magnets to the metal frame above mentioned
This would make the access to the internals very easy
Only the front baffle should be very rigid and bolted to the metal frame
Not really, if they are designed cleverly. My enclosures have no front baffle and I pump a kilowatt plus into each of my six 18" sealed PA subs. The enclosures empty weigh about 9kg, with a first major resonance around 500Hz.Bass box must be very very heavy Like 50 kg
I've been using lead for various uses for over four decades. My wife works with lead and solder daily and has no measurable intake when tested.The very best damping material in the world imho
if only it were not so toxic
Dermal absorption is insignificant, so providing one is not sanding it and breathing in the fine dust, or ingesting it (!) it remains a perfectly safe material to work with.
It's not desperately expensive for the amounts we need for speakers, and is very effective. One must be careful not to add to much, as excess added mass could lower the enclosure's resonances to somewhere they become more audible!
you mean that you use the woofers mounted back to back ? i would like to do with just one front firing wooferNot really, if they are designed cleverly. My enclosures have no front baffle and I pump a kilowatt plus into each of my six 18" sealed PA subs. The enclosures empty weigh about 9kg, with a first major resonance around 500Hz.
have you tried the cup of water test ? to see for any ripples ? that would be the ultimate test
the only way to get a still cabinet is to add mass the more the mass the better This is what almost all designers do
yes but they ring with at a very specific frequency Maybe it is easier to suppress a narrow band ringing with simple adesive absorber like those commonly used in car audioBells can be heavy, and they ring.
actually the cage should be internal acting like a frame on which the various panels are attached in some wayA cage is around the outside, the longest path; you want the shortest path to make something rigid.
i have seen this design and i am very impressed
the woofer must be bolted to the frame i guess
however i have also seen the inside of a Rel sub It has a thick cross acting as bracing in the middle I guess they use mdf so not the best
i wonder if the cross can be made out of metal for extreme stiffness
it is an entry level sub
another solution for bracing Much more complex
A sub can cover easily up to 500Hz Using is just below 100Hz is a waste
The sound of death! 😱
Indeed. If the cabinet sounds dead, then it is lkely a poor result.
dave
dave
Something tnat adds mass wtout addimng stiffeness. Steel cage, if ridgid, is good, adding weights ois counterproductive.
dave
with additional weights bolted to the structure
Something tnat adds mass wtout addimng stiffeness. Steel cage, if ridgid, is good, adding weights ois counterproductive.
dave
yes but they ring with at a very specific frequency Maybe it is easier to suppress a narrow band ringing with simple adesive absorber
If you want to be anal you could tune it such that modern music. (ie recordings) does not provide energy at those frequencies. But a general target of, as high is possible, is good enuff for me,
the woofer must be bolted to the frame
To bolt the woofer to thesteel frame one would have to cleverly design the basket.
A sub can cover easily up to 500Hz Using is just below 100Hz is a waste
A good target, up to 500Hz bandwidth, 100Hz XO.I tend to prefer a larger transition area for the XO, i’d be looking for 1kHz+ for a sub going as high as 100 Hz.
dave
With a little thought it should be perfectly obvious why cuboid boxes need so much complex bracing to reduce panel flexing so they work acceptably well - they are the wrong shape to start with!
To my mind it is rather like building a bicycle with a rubber frame and then having to add all sorts of stiffening elements to make it rideable. Why does everyone seem to take this route when building DIY speakers?
I can understand that slightly more complex woodwork is beyond the capability of some, but it saddens me that there is so much Monkey-See-Monkey-Do in many different hobbies, when there is an almost limitless quantity of inspiration and ideas to be found on the interweb using just a tiny bit of lateral thinking - thinking outside the box, pardon the pun...
Not really, if they are designed cleverly. My enclosures have no front baffle and I pump a kilowatt plus into each of my six 18" sealed PA subs. The enclosures empty weigh about 9kg, with a first major resonance around 500Hz.
Now i want pictures and more details please!
A 6-sided box is overwhelmingly the shape used, from our monkey coffins to the houses we live or work in.
A curved wall cyclider woulkd be better, a sphere ideal from a bracing POV.
Note that a monkey coffin is a cylib=nder with a 4-sided base.
dave
A curved wall cyclider woulkd be better, a sphere ideal from a bracing POV.
Note that a monkey coffin is a cylib=nder with a 4-sided base.
dave
ok but even a stiff cabinet can still shake back and forth in opposition to the woofer cone movementdave
Something tnat adds mass wtout addimng stiffeness. Steel cage, if ridgid, is good, adding weights ois counterproductive.
dave
only a high mass can counteract the forces generated by the cone in its movement
If not why so many extremely heavy floorstander speakers ? there would be no reason to make them so heavy Just stiff could be enough
ok but even a stiff cabinet can still shake back and forth in opposition to the woofer cone movement
Everything resonates. If the (potential) resonances is not excited it is as if there wasn’t one. Your sub operating to 400 hz or so (4th order filter), and the box resoances are >500 Hz there is nothing to get them going.
dave
If you're referring to an article from Hi-Fi World, the composite was veneered MDF outside, and particle board inside. Actually, with the graphs and explanation it all made sense.Shot mixed in silicone is something I have not seen for a while. It's pretty dead sounding.
Composite's seem missing to. MDF inside, chip outside, was the one iirc. However chip is so delicate, nobody uses it much at all for cabinetry.
Applying a little logic, the MDF is rigid but rings. The chip flexes, but doesn't ring.
You can't put the chip inside, as too much energy still reaches the MDF, as chip is bendy, and the MDF can add harmonics it's so stiff. It must be MDF inside, and the chip outside. As a dampening covering.
This wouldn't be waterproof chip, with it's huge resin percentage. This would be cheap chip, ready to fall to bits.
It's fell from flavour. Today we have braces that connect with a depth of sealant, to give the energy some place to go. Dampening panels without shifting the frequency up.
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