Others have to chime in, but the melamine i know of is quite easy to damage/break/tear. Thus easy to cut into a retired shape. It is a quite fine 3 dimensional grid, making sound waves sort of bounce around thus slowing the propagation and absorbing energy. However melamine is quite brittle itself. So foam for kitchen appliance made of melamine is something i find qurious. It may contain melamine though.
The melamine foam for absorption has a much lower weight compared to cotton wool or polyester fibre based absorption material. Fine for road cars etc, but for loudspeakers of no benefit.
My personal finding is that it also poses a higher impedance to air moving through it, compared to cotton, wool or polyester alternatives. So i do not see it a good alternative for (sub) woofer application.
Lastly recently reported melamine poses some health risks .
The melamine foam for absorption has a much lower weight compared to cotton wool or polyester fibre based absorption material. Fine for road cars etc, but for loudspeakers of no benefit.
My personal finding is that it also poses a higher impedance to air moving through it, compared to cotton, wool or polyester alternatives. So i do not see it a good alternative for (sub) woofer application.
Lastly recently reported melamine poses some health risks .
i guess the best is having high density fiberglass?
I dont think cotton can be as absorbant vs high denisty fiberglass. why even use cotton or wool?
I dont think cotton can be as absorbant vs high denisty fiberglass. why even use cotton or wool?
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Well check the absorption graphs as presented by the manufacturers, or by researchers. Cotton (shredded denim) is very effective, as is polyester fibre based .
Fibreglass i prefer not to use, may be the modern versions may be better, but it used to be brittle and sort of break down into shorter fibres and thus its absorption reduces. Also it was not a high absorbing matter in the first place.
Fibreglass i prefer not to use, may be the modern versions may be better, but it used to be brittle and sort of break down into shorter fibres and thus its absorption reduces. Also it was not a high absorbing matter in the first place.
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right
Ive looked at ultratouch denim and indeed, at layers smaller then 4" thick, its almost unbeatable
https://gearspace.com/board/studio-...ch-denim-insulation-superior-bass-buster.html
this is what i use in my midrange cabinet. i wonder if I should try various material, measure, report back.
also i should try various levels of diffraction directly behind the driver
Ive looked at ultratouch denim and indeed, at layers smaller then 4" thick, its almost unbeatable
https://gearspace.com/board/studio-...ch-denim-insulation-superior-bass-buster.html
this is what i use in my midrange cabinet. i wonder if I should try various material, measure, report back.
also i should try various levels of diffraction directly behind the driver
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It seems that the "magic eraser sponge" foam cleaning pad is identical to BASF Basotect melamine foam.
https://www.diyaudio.com/community/...th-order-bandpass.268524/page-69#post-7185967
As I have said, I have no experience with this material as an acoustic absorber, but many people have had positive results.
On the other hand, I use melamine foam pads for general cleaning work all the time. As JanRSmit has said, this material is rather delicate. When cleaning, it tends to fragment and disintegrate. It is amazing how it will abrasively clean even the most delicate of surfaces without leaving scratches.
https://www.diyaudio.com/community/...th-order-bandpass.268524/page-69#post-7185967
As I have said, I have no experience with this material as an acoustic absorber, but many people have had positive results.
On the other hand, I use melamine foam pads for general cleaning work all the time. As JanRSmit has said, this material is rather delicate. When cleaning, it tends to fragment and disintegrate. It is amazing how it will abrasively clean even the most delicate of surfaces without leaving scratches.
Wool is excellent. 100% wool batting for quilts is reasonable priced. Not quite as much value/dollar as the denim, but wool doesn't shed like mad either. You can see some of testing here: https://www.somasonus.net/box-construction-methods
Melamine is fantastic, but I've never found it reasonably priced.
One of the advantages of an aperiodic. midTL is that it works to minimise the time-smear from stiff coming back thru the cone.
It can also flatten the impedance, making for an easier passive XO. For example.
Unless you need to extend the LF response, larger than needed for butterworth Q is not a hardship.
dave
It is on my long list of todos to one day compare. I have both at home and the acoustic stuff seems to have more air in it than a mr. clean eraser.
https://www.mscdirect.com/browse/tn...efinements=Brand:American+Acoustical+Products
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If you want to use melamine for dampening, make sure its 100 percent Basotec or equivalent. I've tried the cheap stuff ie budget magic eraser foam and it doesn't behave the same.
I like melamine foam on the enclosure walls and loose wool over it. That works far better than either one alone, especially terminating it in a tapered line. You end up with a very inert sounding enclosure and it pulls out much of the lower end peak if Qtc is on the high side.
I like melamine foam on the enclosure walls and loose wool over it. That works far better than either one alone, especially terminating it in a tapered line. You end up with a very inert sounding enclosure and it pulls out much of the lower end peak if Qtc is on the high side.
This stuff is 100 percent Basotec and a great deal. I order from these guys alot. Free shipping too.
https://www.spongeoutlet.com/product/eraser-sponge-210-pack/
https://www.spongeoutlet.com/product/eraser-sponge-210-pack/
well, thats exactly what i needed. I couldnt source real Basotect.
just ordered! thx!
im thinking to cover the midrange lining with it, and add a lyer of ultratouch denim in top.
for bass cabinet, high density fiberglass should work just as well or you also think bsotect sounds better for woofers?
For those in Europe, I have ordered basotect from here: https://www.eurokustik.com/english/acoustic-foam-basotect.html
No problems, and customer service has been very good too.
No problems, and customer service has been very good too.
I am just a hobbyist that has compared a few different ways stuff a box...
I agree with using more than one material. Any material will add its own decay curve to the box. Also, all materials work better with air space. I keep the foam 2"-4" from the back wall and stuff behind it with some fiber. If you have 1" of foam against a wall then only a fraction of that is doing any work- it is a waste.
IMO eq can often do a better job than some material that is messing with a wide range of frequencies. Measure the cone and see what an empty box is doing. You can slow down a driver with too much stuffing. An empty box has more spring than a box with foam. Somewhere between is the answer.
I looked up the docs. Just because it has the brand does not mean you are buying the right one. The grey version is what you want.
https://www.construction.basf.us/files/pdf/Basotect_brochure.pdf
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This is an interesting subject. I've basically played with 5 different kinds of stuffing over the years... pillow stuffing, acousti-stuff, denim, dacron, and egg-crate foam. The one that seemed to cure the "boxy midrange" sound the best without changing too much elsewhere was simply using a single layer of egg-crate foam behind the midrange.
Edit: I've played with 7, I forgot about this adhesive backed, closed cell foam I used once that was around 1" thick. I got it from an auto plant I do business with and it was some sort of sound deadening. That actually seemed to make a positive difference, but I can't quantify why and maybe the difference was imagined. The 7th was some stuff called "Black Hole", expensive and not so sure it made a lot of difference to be honest.
I currently have a 3 way that I lined the midrange cabinet with using denim, not overly stuffed, basically just enough to line the walls of the cabinet, but it was thicker denim stuffing. While I have not tested this yet, I think doing this gave a disjointed sounding midrange compared to what it was unstuffed; with the stuffing it sounds like the midrange has a wider soundstage, but it's almost too wide. In other words, I (think I) preferred this one not stuffed but I still need to take it out and re-listen.
Also, in my experience, unless you get crazy with stuffing a midrange, stuffing rarely (actually never) made enough of a difference in a measurement to make me raise an eyebrow, everything stuffing has done for me has been purely subjective. Not saying I've played with it all, but that's been my experience so far.
Lastly... Also IME, the answer to "which midrange stuffing" is going to be different depending on the driver and the cabinet- you might prefer different stuffing with different mids. Best you can do is play, and while playing don't expect night and day differences with different stuffing, unless you're overstuffing the cabinet. To my ears (and microphone) the differences are very subtle, if audible at all.
Edit: I've played with 7, I forgot about this adhesive backed, closed cell foam I used once that was around 1" thick. I got it from an auto plant I do business with and it was some sort of sound deadening. That actually seemed to make a positive difference, but I can't quantify why and maybe the difference was imagined. The 7th was some stuff called "Black Hole", expensive and not so sure it made a lot of difference to be honest.
I currently have a 3 way that I lined the midrange cabinet with using denim, not overly stuffed, basically just enough to line the walls of the cabinet, but it was thicker denim stuffing. While I have not tested this yet, I think doing this gave a disjointed sounding midrange compared to what it was unstuffed; with the stuffing it sounds like the midrange has a wider soundstage, but it's almost too wide. In other words, I (think I) preferred this one not stuffed but I still need to take it out and re-listen.
Also, in my experience, unless you get crazy with stuffing a midrange, stuffing rarely (actually never) made enough of a difference in a measurement to make me raise an eyebrow, everything stuffing has done for me has been purely subjective. Not saying I've played with it all, but that's been my experience so far.
Lastly... Also IME, the answer to "which midrange stuffing" is going to be different depending on the driver and the cabinet- you might prefer different stuffing with different mids. Best you can do is play, and while playing don't expect night and day differences with different stuffing, unless you're overstuffing the cabinet. To my ears (and microphone) the differences are very subtle, if audible at all.
my understanding is that its near impossible to measure the decay response of the inner cabinet, since it will always be buried by the direct sound of the drivers
how can anyone even measure the effect of inner cab decay if its impossible to measure the amount being reflected back thrue the cone?
if I were you, id trust my subjective experience. if you prefer no stuffing, i would go for it. then try different material to see if stuffing in your speaker always negatively effect subjective sq...
how can anyone even measure the effect of inner cab decay if its impossible to measure the amount being reflected back thrue the cone?
if I were you, id trust my subjective experience. if you prefer no stuffing, i would go for it. then try different material to see if stuffing in your speaker always negatively effect subjective sq...
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Agree 100%. My subjective opinion so far based on my playing around is... there's no one answer to this question, the answer depends on the midrange and the cabinet it's in, and probably also depends on the crossover we chose. Best we can do is play around with it and try different things until we find the one we enjoy the most.
In my link a few posts back, I measured what came through the speaker cone. The source driver was effectively inside the cabinet.
Well the best answer based on my 35 yrs of speaker building is that it depends on what type of driver you're using and what kind of bandwidth you're trying to tame.
I prefer minimal dampening in the bass, given the driver Qts is within preferable range to start with. If you're trying to put a bandaid on a high Qts driver in too small of volume sealed, you'll need more dampening but the trick is not to kill the lower mids too much and end up with a lean sounding peaky bass response that has no lower mids. For heavy dampened sealed boxes I would use mineral wool and shield the driver internals with a layer of grille cloth over the mineral wool, so nothing gets inside the VC gap over time.
Ported boxes are a whole different animal. You have to avoid hindering the airflow to the vent while soaking up all the mids that spill into the box, so they don't leak back out of the driver cone. I would use a light layer of mineral wool on the walls and baffle the LF driver with a pillowed layer of sheeps wool right behind it in a U formation. I use chicken fence wire to hold the wool pillow baffle in place and staple the wire edges to the enclosure walls. That way you don't skew the enclosure tuning too much from predicted results. If you want to go further and get better bass impulse response, you can use a critically dampened port arrangement. Otherwise I'd choose a driver with Qts of .38 to .42 and tune Fb=Fs.
The benefits of Melamine foam is the linearity of absortion it provides in the mids while not hindering the bass as much, so you get better midrange response. It provides a warmer sound than fiberglass or mineral wool if used on the enclosure walls. Merino wool takes it a step further and really cleans up the mids without over doing it, like mineral wool or fiberglass has a tendency to do.
For a midrange enclosure its best to avoid parallel walls and lightly stuff with lower density materials ie. roving merino sheeps wool and melamine foam on the cabinet walls. Use a large enough enclosure size to push Fb down far enough to keep the resonance at least an octave away from the xover HP ie. if Fb=150 hz then cross over higher than 300 hz. If you're closer than that with your HP then critically dampen the driver with an LCR notch and/or stuff the enclosure with sheeps wool until you get a Qtc of .5
How did you come to the conclusion 13 degrees angle is preferred?
I would always aim for an angle of more than 45 degrees (not parallel to any other panels) to redirect any direct reflections away from the driver asap, before they even have the chance to reflect another time. This is why I prefer an unbacked absorption baffle with merino wool shaped in a U right behind the driver to soak up anything before it gets any further. This is one of the best ways to dampen a ported cab without killing the lower mids with excessively thick dampening material on the enclosure walls. A described baffle like this alone is very effective, sort of like screaming into a pillow.