Imperfections add character right ? or maybe thats just with people 😀
I'm staring at a screen full of dampening material but i'm not sure what to pick... there are no descriptions.
The plans (planet hifi Fonken) say i should use either 12mm wool felt, 19mm poly fluff batting (?) or 25mm fiberglass.
Not sure which qualify of the ones that are displayed in the above link.
How critical is picking the right dampening material ?
I'm staring at a screen full of dampening material but i'm not sure what to pick... there are no descriptions.
The plans (planet hifi Fonken) say i should use either 12mm wool felt, 19mm poly fluff batting (?) or 25mm fiberglass.
Not sure which qualify of the ones that are displayed in the above link.
How critical is picking the right dampening material ?
This qualifies as wool -- but it isn't clear whether it is loose or a felt blanket (looks to be the former) http://www.bmm-electronics.nl/Product.asp?Product_ID=6820
If the above is loose, my next choice would be this http://www.bmm-electronics.nl/Product.asp?Product_ID=6817
dave
If the above is loose, my next choice would be this http://www.bmm-electronics.nl/Product.asp?Product_ID=6817
dave
Hugo -
The cotton felt material that the Planet10 fabrication team ( me) uses is recycled from vintage (mostly Japanese) loudspeaker enclosures, and we haven't conducted exhaustive testing of alternative materials readily available.
I have used some compressed automotive carpet underlay that is in good part recycled cotton (shredded denim, etc), which is locally available in approx the same 1/2" or so, and even a cotton fibre home insulation product.
http://www.bondedlogic.com/ultratouch.htm
Unfortunately the minimum thickness in which the latter is available is 2", and the manner in which it's loosely bonded makes it a PITA to separate to thinner layers.
Jim Shearer has found great results with his Fonkens, using a foam material. If you've not already seen it, posts 7 through 11 of this thread are worth a read.
http://www.diyaudio.com/forums/showthread.php?postid=1707865#post1707865
The cotton felt material that the Planet10 fabrication team ( me) uses is recycled from vintage (mostly Japanese) loudspeaker enclosures, and we haven't conducted exhaustive testing of alternative materials readily available.
I have used some compressed automotive carpet underlay that is in good part recycled cotton (shredded denim, etc), which is locally available in approx the same 1/2" or so, and even a cotton fibre home insulation product.
http://www.bondedlogic.com/ultratouch.htm
Unfortunately the minimum thickness in which the latter is available is 2", and the manner in which it's loosely bonded makes it a PITA to separate to thinner layers.
Jim Shearer has found great results with his Fonkens, using a foam material. If you've not already seen it, posts 7 through 11 of this thread are worth a read.
http://www.diyaudio.com/forums/showthread.php?postid=1707865#post1707865
chrisb said:
The cotton felt is mostly from Canadian (Noresco) enclosures, the wool felt from Japanese speakers -- when i'm out collecting used speakers (not nearly so often these days), the damping material is sometimes as valuable to us as the drivers.
dave
For easy reference:
The foam I used on the Fonkens and Metronomes is:
Parts Express #260-520 Sonic Barrier Foam 0.5" w/ pressure sensitive adhesive backing.
The holey brace got one side covered w/ 0.5" poly batting swiped from my wife's sewing supplies.
Cheers, Jim
The foam I used on the Fonkens and Metronomes is:
Parts Express #260-520 Sonic Barrier Foam 0.5" w/ pressure sensitive adhesive backing.
The holey brace got one side covered w/ 0.5" poly batting swiped from my wife's sewing supplies.
Cheers, Jim
Does the internal bracing need dempening aswell as the outer panels ? same material ?
I think I can recall seeing a Fonken with the bracing also dampened.
I underestimated the total cost of the build abit, i'm at €170 everything included.... set of FE127E, wires, 2 sets of spikes, 2 sets of terminals and dampening and i haven't got any wood/mdf yet either
There goes the budget 😀 .... but thats ok, i;m getting more and more excited about building it 🙂
Is there anything i'm forgetting ?
/edit
Just noticed.... why is the internal bracing not in the middle but a little to the side ?
/edit 2
@ below - yeh sorry, just saw your post in the other thread... was just coming here to edit this post again.
Cheers 🙂
I think I can recall seeing a Fonken with the bracing also dampened.
I underestimated the total cost of the build abit, i'm at €170 everything included.... set of FE127E, wires, 2 sets of spikes, 2 sets of terminals and dampening and i haven't got any wood/mdf yet either
There goes the budget 😀 .... but thats ok, i;m getting more and more excited about building it 🙂
Is there anything i'm forgetting ?
/edit
Just noticed.... why is the internal bracing not in the middle but a little to the side ?
/edit 2
@ below - yeh sorry, just saw your post in the other thread... was just coming here to edit this post again.
Cheers 🙂
Hugo82 said:
In any box the most effective place o damp a side-to-side m(or front-to-back or top-to-bottom) standing wave is in the middle of the b ox. The centre side of the holey brace makes a nice place to take advantage of this. So yes... a layer of damping om the holey brace over the cutouts.
http://www.diyaudio.com/forums/showthread.php?postid=1708152#post1708152
dave
don't be surprised if Dave answers some of these questions as well - we have a lot of affection for this particular design, and tend to be a bit protective
yes, padding to one side of the off-centre brace only (see below)
having built many pairs of these, I'd respectfully suggest that you try to stretch your budget to include baltic birch or equivalent plywood, not MDF.
plan your assembly to fit the back panel on last - either by rabbetting the back panel in, or cutting the outside panel walls narrower and simply overlaying the back panel. This is not a large enclosure, and putting the back on last makes for much easier installation of the damping materials
make sure you bevel the backside of the driver cutout
to redistribute panel resonances over unequal frequencies
Hugo82 said:
yes, padding to one side of the off-centre brace only (see below)
I underestimated the total cost of the build abit, i'm at €170 everything included.... set of FE127E, wires, 2 sets of spikes, 2 sets of terminals and dampening and i haven't got any wood/mdf yet either
There goes the budget 😀 .... but thats ok, i;m getting more and more excited about building it 🙂
Is there anything i'm forgetting ?
having built many pairs of these, I'd respectfully suggest that you try to stretch your budget to include baltic birch or equivalent plywood, not MDF.
plan your assembly to fit the back panel on last - either by rabbetting the back panel in, or cutting the outside panel walls narrower and simply overlaying the back panel. This is not a large enclosure, and putting the back on last makes for much easier installation of the damping materials
make sure you bevel the backside of the driver cutout
to redistribute panel resonances over unequal frequencies
Cheers for the replies 🙂
1 more question (i'm sure there are more to follow)
Floorstanding speakers sometimes have some sort of mass loading aplied to lessen resonance.
My dad used to have 2 massive floorstanding speakers for wich he build the cabinet himself (like 20 years ago, doesnt have them anymore) they weighed +-80kg a piece, both had something like 35-40kg of some kind of sand in them.
Not any helpfull info but just a little background story 🙂
There is none in the fonken design so i'm willing to take a guess that it's not needed 😉 but can it hurt ?
Is there something to be gained (except weight 😉 ) by doing this ?
1 more question (i'm sure there are more to follow)
Floorstanding speakers sometimes have some sort of mass loading aplied to lessen resonance.
My dad used to have 2 massive floorstanding speakers for wich he build the cabinet himself (like 20 years ago, doesnt have them anymore) they weighed +-80kg a piece, both had something like 35-40kg of some kind of sand in them.
Not any helpfull info but just a little background story 🙂
There is none in the fonken design so i'm willing to take a guess that it's not needed 😉 but can it hurt ?
Is there something to be gained (except weight 😉 ) by doing this ?
Hugo - while there was no provision in the "prime" or smaller bookshelf / stand mounted members of the Fonken family for the kind of mass loading via sand that you're talking about, the Floorstander does.
On designs as narrow and tall as these, or even small BLH (Frugelhorn, Buschhorn, Hornshoppe, etc.), it is as much for stability as anything - but yes a certain amount of mass such as this can serve as a bit of a sink for some of the enclosure's resonant energy, and help improve mid-bass.
In the case of the stand mounted enclosures, I'm using a cheap commercial stand that has a pair of approx 2 1/2" metal upright tubes, which are filled with glass bead "sand-blasting" media. It's a coarser grain than sand, and perhaps less dense, but works well enough.
On designs as narrow and tall as these, or even small BLH (Frugelhorn, Buschhorn, Hornshoppe, etc.), it is as much for stability as anything - but yes a certain amount of mass such as this can serve as a bit of a sink for some of the enclosure's resonant energy, and help improve mid-bass.
In the case of the stand mounted enclosures, I'm using a cheap commercial stand that has a pair of approx 2 1/2" metal upright tubes, which are filled with glass bead "sand-blasting" media. It's a coarser grain than sand, and perhaps less dense, but works well enough.
the "MUHWOLLE/1000" is much denser than wool...
if you cannot get felt, you can try the stuff often used under carpets: "ondertapijt". just use enough to get to the required thickness
on the paint job: I once had a speaker finnished at a body shop, result was 90% very good, but the 10% not good was on the corners where the glue from in between the MDF had caused the paint not to attach. so if you go that route: good pretreatment is key.
if you cannot get felt, you can try the stuff often used under carpets: "ondertapijt". just use enough to get to the required thickness
on the paint job: I once had a speaker finnished at a body shop, result was 90% very good, but the 10% not good was on the corners where the glue from in between the MDF had caused the paint not to attach. so if you go that route: good pretreatment is key.
Do u use that ondertapijt yourself Henkjan ?
If not what do u use and might i ask where u get it ? 🙂
What exactly do u mean with body shop, do u mean a car garage with a paintspraying booth ? that kind ?
Sounds like that could be expensive.
I'm guessing it's a good idea to mirror the bracing in the second speaker ?
If not what do u use and might i ask where u get it ? 🙂
What exactly do u mean with body shop, do u mean a car garage with a paintspraying booth ? that kind ?
Sounds like that could be expensive.
I'm guessing it's a good idea to mirror the bracing in the second speaker ?
Hugo82 said:
I'm pretty sure that's exactly what he means, and yes a pro grade paint job can easily cost more than the rest of the speaker enclosure.
That's only one of the reasons I like to veneer.
I doubt it's sonically necessary, but it couldn't hurt.
I use thick felt for on the wall and BAF (sold under the name of Sonofil) for volume damping. I heard other people have succesfully used the "ondertapijt" when they could not get felt. I got some felt from another DIYer, I forgot where he bought itHugo82 said:
yes, that's what I mean. and yes, that is expensive. I paid over 120 euros for a pair of Needles, and that was a "vriendenprijs" (yes, that was more than the complete box, enclosure, drivers, filter)Hugo82 said:
Well i guess thats it.... i ordered everything.... no way out now 🙂
The normal Fonken is quite big for desktop use so i might end up trying both the normal Fonken and the smaller version, don't know yet.
I'll probably make some tiny stands for them to put the speakers on ear level.
I'll keep u guys updated. 🙂
The normal Fonken is quite big for desktop use so i might end up trying both the normal Fonken and the smaller version, don't know yet.
I'll probably make some tiny stands for them to put the speakers on ear level.
I'll keep u guys updated. 🙂
Parts finally arrived, i'm now calculating how much wood i need for the cabinets.
The thickness of the wood in the plans are 1/2" and 3/4" which is 13mm and 19mm
But here we only have it 12mm and 18mm flavors.
Do i need to recalculate everything or is that difference so minimal that i shouldnt worry.
I Think the most critical (if i can speak in those terms) part would be the ports.
So what should i do ?
The thickness of the wood in the plans are 1/2" and 3/4" which is 13mm and 19mm
But here we only have it 12mm and 18mm flavors.
Do i need to recalculate everything or is that difference so minimal that i shouldnt worry.
I Think the most critical (if i can speak in those terms) part would be the ports.
So what should i do ?
port size and internal volume should be as close to original as possible, where port size probably has the larger effect if there is a difference compared to the original. for the internal volume, a few % will not make a big difference, the manufacturing tolerances of the driver will most likely have a larger spread
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