Vovo, most cabinet makers and some suppliers will cut MDF if you buy a sheet, most will charge about $2- a cut.
But you have to supply the cutting data; outlining the cut sizes and number of panels at each size, not that hard to work out and most places with a big table saw can work to plus or minus 1mm.
Do a quick search thru the yellow pages for your area for MDF and Plywood suppliers.
Thats how I have been doing it while I save for a saw bench, but buy a good router, Triton are expensive but do come with a circle cutting guide that is quite workable.
But you have to supply the cutting data; outlining the cut sizes and number of panels at each size, not that hard to work out and most places with a big table saw can work to plus or minus 1mm.
Do a quick search thru the yellow pages for your area for MDF and Plywood suppliers.
Thats how I have been doing it while I save for a saw bench, but buy a good router, Triton are expensive but do come with a circle cutting guide that is quite workable.
so if I increased the internal dimensions to
334 x 214 x 268 would I be breaking any rules or stuffing up the acoustics.
How do you relate phi to any dimensions in speaker design? I checked a few and closest I could find in your design seems to be the placement of the cross member beam.
Also what is the theory regarding the chamfer?
Thanks guys really appreciate the help.
I have been quoted $132 for CNC routed 18mm MDF is that right or a bit dear for a speaker cabinet?
This adds up quickly
anything I have left out
$290 drivers
$80 cross overs and posts
$132 MDF
$50 Cabinets finish including PVA
$20 delivery
+10%
$~620 anything I have missed out
Would be nice to get the MDF cheaper, might be able to get it down to $500 all done if I don't use any contingency.
334 x 214 x 268 would I be breaking any rules or stuffing up the acoustics.
How do you relate phi to any dimensions in speaker design? I checked a few and closest I could find in your design seems to be the placement of the cross member beam.
Also what is the theory regarding the chamfer?
Thanks guys really appreciate the help.
I have been quoted $132 for CNC routed 18mm MDF is that right or a bit dear for a speaker cabinet?
This adds up quickly
anything I have left out
$290 drivers
$80 cross overs and posts
$132 MDF
$50 Cabinets finish including PVA
$20 delivery
+10%
$~620 anything I have missed out
Would be nice to get the MDF cheaper, might be able to get it down to $500 all done if I don't use any contingency.
Hi Vovo, I just ran Ralphs dimensions thru the calculator and got a volume of 49 liters.
When we build speakers it is usually the internal dimensions we talk about, because it is internal volume that counts.
If you build a ported box I believe it is usual to take the volume of the driver and the volume that the port occupies from the internal volume.
So the dimensions you give yield a 19.15 box, from which volume you should subtract driver displacement and port displacement to give the final internal volume.
I like to have my boxes deeper rather than wider, but really that is a personal preference.
I personally don't think that it is necessary to have the whole box CNC routed, just the holes and countersinking on the baffle, can you have the panels table cut and just the baffle routed.
$132 is half way to a good router
When we build speakers it is usually the internal dimensions we talk about, because it is internal volume that counts.
If you build a ported box I believe it is usual to take the volume of the driver and the volume that the port occupies from the internal volume.
So the dimensions you give yield a 19.15 box, from which volume you should subtract driver displacement and port displacement to give the final internal volume.
I like to have my boxes deeper rather than wider, but really that is a personal preference.
I personally don't think that it is necessary to have the whole box CNC routed, just the holes and countersinking on the baffle, can you have the panels table cut and just the baffle routed.
$132 is half way to a good router
vovo said:
Leave the internal width and depth the same and only change the height. For 18 litres the port would be about 110mm long for the same tuning but tune for taste. The baffle width is important and can effect the crossover. The cross brace would have to be lowered to achieve the same ratio. The internals of the original allows for 1.3 litres of bracing so you would need a box of 19.3 litres to achieve the Vb.
See post below for the original 14 litre (Vb) box.
http://www.diyaudio.com/forums/showthread.php?postid=1836975#post1836975
Phi is only one number and only given as an example but there are heaps of others and more are obtained by sq root of those numbers etc.
Chamfer is to assist airflow behind the driver.
Yeah that might not be a bad Idea getting only the Baffles CNC Routed.
Though now I am really thinking about going floorstander, seems to give much better performance and the cost seems to be the about the same as pretty much all the dimensions should fit on a 1200x2400 piece of MDF. It is for use in a bedroom, but I would probably have to buy stands if I wanted accurate imaging with bookshelves.
Will see if I can borrow a router from somewhere.
Thanks guys
Though now I am really thinking about going floorstander, seems to give much better performance and the cost seems to be the about the same as pretty much all the dimensions should fit on a 1200x2400 piece of MDF. It is for use in a bedroom, but I would probably have to buy stands if I wanted accurate imaging with bookshelves.
Will see if I can borrow a router from somewhere.
Thanks guys
I'm basically lazy and cheap.
Quite often I build speakers that use a cabinet height of 1220mm, that way I only have to pay for half the number of cuts.
If that makes the volume to much I've put in a false floor section and put the XO in there.
long skinny boxes are supposed to suffer from Organ Pipe resonance problems but I've always used lots of damping fibre in my builds so never noticed.
Regards Ted
Quite often I build speakers that use a cabinet height of 1220mm, that way I only have to pay for half the number of cuts.
If that makes the volume to much I've put in a false floor section and put the XO in there.
long skinny boxes are supposed to suffer from Organ Pipe resonance problems but I've always used lots of damping fibre in my builds so never noticed.
Regards Ted
Moondog55, you lazy dog! oh well, at least you end up with the tweeter at ear height when your sitting down 😉
col.
col.
I'm about to knock up a pair of Hemp Acoustics FR8C BR floorstanders. Need something like 80-120lt. I can freely obtain a few 12mm 1220x2400 sheets. Might make them 1220mm high to save on cutting. Will probably need to double up for thickness, not sure how accurate my cutting with a hand held circular saw is though. Any tips?
col.
col.
Woo, go everyone else!
My speakers are progressing slowly, but progressing nonetheless!
The important XO components have arrived from speakerbug, incredibly fast!!! Well recommended!
The rest of the crossover I'll pick up from Jaycar and while I'm there I'll pick up some banana plugs and speaker stuffing.
My dad found a job so won't have as much time to help out, but come to think of it he should have access to any tools we may need now. I'll mark out what I need cut and routed when I have time and let him work around his schedule.
I'm so excited!
🙂
My speakers are progressing slowly, but progressing nonetheless!
The important XO components have arrived from speakerbug, incredibly fast!!! Well recommended!
The rest of the crossover I'll pick up from Jaycar and while I'm there I'll pick up some banana plugs and speaker stuffing.
My dad found a job so won't have as much time to help out, but come to think of it he should have access to any tools we may need now. I'll mark out what I need cut and routed when I have time and let him work around his schedule.
I'm so excited!
🙂Matt,
Since this is pretty much your baby, why don't you name it. Give it a speaker type name, provided its reasonably decent I would be happy to use it for mine.
Maybe a cool amalgamation of the user names of the three that put so much into it?
maybe a different model number for sealed, ported and floorstander?
Since this is pretty much your baby, why don't you name it. Give it a speaker type name, provided its reasonably decent I would be happy to use it for mine.
Maybe a cool amalgamation of the user names of the three that put so much into it?
maybe a different model number for sealed, ported and floorstander?
Honestly; while i admit to being a little flattered here, I can't take any credit . all I offered was encouragement and links to information.
Any credit goes to Rabbitz and Ralph Waters.
RabbitWaters #1* ???????? 😀
Any credit goes to Rabbitz and Ralph Waters.
RabbitWaters #1* ???????? 😀
Moondog55 said:
Around 100mm-150mm of damping material in the bottom of the box helps here.
There's an example at Zaph's in the section 2-way enclosure. You can see the difference in the impedance plots with and without.
http://www.zaphaudio.com/ZRT.html
col said:
I swear by ProGrip fences. I keep 2 sizes, 24" & 50".
http://www.carbatec.com.au/clamps-vises/progrip-system/progrip-fences
A straight edge made from MDF also works well with clamps but I find these quicker and easier.
This is really Ralph's baby as it's his drivers, concept, crossover. I've just done some checks and numbers and put it into a format that's easier to read for those interested.
Rabbitz I admire honest modesty, but you do have the ability to make some of the more difficult parts of the subject easier to understand, stand up and take a bow.
How about making them all floor-standers and calling them the
"Water Towers"😀 🙄 😀 🙄
How about making them all floor-standers and calling them the
"Water Towers"😀 🙄 😀 🙄
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