Hi everyone - These are some ribbon speakers I am in the progress of building - They are really in a prototyping stage right now - experimenting with ribbon thickness, rear chamber stuffing etc.. - I have designed the motor so I can adjust the gap from 20mm down to 5mm - I have no transformer yet so I'm just using resistors to make measurements (very inefficient) The plan is to keep this thread updated as progress is made.
Current Specs:
Magnets: Neo N40 4"x1/2"x1/2"
Ribbon size: 20mm x 100mm
Current Specs:
Magnets: Neo N40 4"x1/2"x1/2"
Ribbon size: 20mm x 100mm
Attachments
Hi Andrew
May I ask where you obtained your magets ? nd for how much ? -I am also in the land of OZ and finding neos at a sensible price is difficult.
AS you seem to have access to FR measuring equipment, could I suggest doing a comparison with pleated diaphrams (see my earlier post at
http://www.diyaudio.com/forums/showthread.php?s=&postid=1420220#post1420220
for a quick and dirty method to produce them.
I am considering making a pair similar to those you have and am concerned at the affect of stuffing in the enclosure.
From my experiments my ribbons seems to sound best with no enclosure behind - some absorption to cut down bouncing off the walls can help though.
Also - ribbon material- not knowing what thicknesses are avaialbel ready I took the approach of assuming that the cheapest and nastiest kitchen foil would most ikely be the thinnest. To this end I'm using "Black and Gold" from one of the supermarkets.
What did you use?
Cheers
george
May I ask where you obtained your magets ? nd for how much ? -I am also in the land of OZ and finding neos at a sensible price is difficult.
AS you seem to have access to FR measuring equipment, could I suggest doing a comparison with pleated diaphrams (see my earlier post at
http://www.diyaudio.com/forums/showthread.php?s=&postid=1420220#post1420220
for a quick and dirty method to produce them.
I am considering making a pair similar to those you have and am concerned at the affect of stuffing in the enclosure.
From my experiments my ribbons seems to sound best with no enclosure behind - some absorption to cut down bouncing off the walls can help though.
Also - ribbon material- not knowing what thicknesses are avaialbel ready I took the approach of assuming that the cheapest and nastiest kitchen foil would most ikely be the thinnest. To this end I'm using "Black and Gold" from one of the supermarkets.
What did you use?
Cheers
george
Hi George A
That's funny because I'm currently using Home Brand foil - noticed how thin it is- I'm thinking between 15um down to 9um - I'm going to try to figure out what thickness it is today by dividing the cu/m weight of aluminium by say a 1m x 30cm long peice of the foil with some accurate scales I picked up today.
-I know what you mean about prices in Australia, the land of the greedy importer/distributor -
As for the magnet source I grabbed mine from:
http://www.magnet4less.com/index.php?ref=90&cPath=1
I thought I'd just attach my order so you could see prices/shipping.
14 x 4" x 1/2" x 1/2" Thick, Grade N42, Ni-Cu-Ni Plated Neodymium Block Magnet (NB075-3) = $70.00
4 x 2" x 1/2" x 1/2" Thick, Grade N45, Ni-Cu-Ni Plated Neodymium Block Magnet (NB054) = $10.56
1 x Magnet Pole Detector - Identifier (POLE-1) = $24.99
24 x 1/2" x 1/8" x 1/4" Rare Earth Neodymium NdFeB Block Magnets, Grade N42 (NB015) = $3.12
------------------------------------------------------
Sub-Total: $108.67
USPS Canada & International Flat Rate (Small International Priority Mail Box: Estimated Transit 7 - 14 Days *Read Disclaimer): $43.95
Total: $152.62
A month ago I set up a thread trying to get some sources listed for cheap neo magnets - have a look at the feedback so-far:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128148
I'll try to get some measurments going - but I'd really like to get a good transformer on the ribbon before doing so. But I guess no harm in trying with resistors?
PS. I sent you a P.M.
Cheers
Andrew
That's funny because I'm currently using Home Brand foil - noticed how thin it is- I'm thinking between 15um down to 9um - I'm going to try to figure out what thickness it is today by dividing the cu/m weight of aluminium by say a 1m x 30cm long peice of the foil with some accurate scales I picked up today.
-I know what you mean about prices in Australia, the land of the greedy importer/distributor -
As for the magnet source I grabbed mine from:
http://www.magnet4less.com/index.php?ref=90&cPath=1
I thought I'd just attach my order so you could see prices/shipping.
14 x 4" x 1/2" x 1/2" Thick, Grade N42, Ni-Cu-Ni Plated Neodymium Block Magnet (NB075-3) = $70.00
4 x 2" x 1/2" x 1/2" Thick, Grade N45, Ni-Cu-Ni Plated Neodymium Block Magnet (NB054) = $10.56
1 x Magnet Pole Detector - Identifier (POLE-1) = $24.99
24 x 1/2" x 1/8" x 1/4" Rare Earth Neodymium NdFeB Block Magnets, Grade N42 (NB015) = $3.12
------------------------------------------------------
Sub-Total: $108.67
USPS Canada & International Flat Rate (Small International Priority Mail Box: Estimated Transit 7 - 14 Days *Read Disclaimer): $43.95
Total: $152.62
A month ago I set up a thread trying to get some sources listed for cheap neo magnets - have a look at the feedback so-far:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128148
I'll try to get some measurments going - but I'd really like to get a good transformer on the ribbon before doing so. But I guess no harm in trying with resistors?
PS. I sent you a P.M.
Cheers
Andrew
Ok - correct me if I'm wrong...
weighed some Home Brand foil - 0.4m2 worth = 10g
which = 25g/m2
Aluminium weighs around 2700kg/m3
so 1um is 0.001mm or 0.000001m
add it all together and 1um aluminium is 2.7g/m2
divide the foil "g/m2" by 2.7 to get the thickness
HomeBrand Aluminium Foil = 9.2um
Still a bit thick as I would like to find under 5um, RAAL ribbons use 4um
Also, I read halving thickness/weight of the ribbon increases efficiency by 6dB
weighed some Home Brand foil - 0.4m2 worth = 10g
which = 25g/m2
Aluminium weighs around 2700kg/m3
so 1um is 0.001mm or 0.000001m
add it all together and 1um aluminium is 2.7g/m2
divide the foil "g/m2" by 2.7 to get the thickness
HomeBrand Aluminium Foil = 9.2um
Still a bit thick as I would like to find under 5um, RAAL ribbons use 4um
Also, I read halving thickness/weight of the ribbon increases efficiency by 6dB
Consider measuring with a flush planar baffle on all 4 sides - no gaps (will effect the extreme HF) - that will tell you another story about the response compared to free air.
Also, consider the purpose of the corrugations found in most ribbon speakers - perhaps you want to add some? It might be sufficient to add just one or two on the ends...
Nice looking work.
Consider using the closeup feature on ur digital camera, the image is a bit fuzzy... but it looks good.
_-_-bear
Also, consider the purpose of the corrugations found in most ribbon speakers - perhaps you want to add some? It might be sufficient to add just one or two on the ends...
Nice looking work.
Consider using the closeup feature on ur digital camera, the image is a bit fuzzy... but it looks good.
_-_-bear
I have to be honest the progress so far was just me hooking it up to check if the magnetic motor worked - while I was there I thought I'd do some tests while I was there. I have to get a baffle set-up going and corrugations are planned.
The fuzzy picture is couresy of the iPhone and it's lack of any autofocus. I'll take some better pictures soon - When I've sorted a better ribbon mounting setup as there's no real point now.
Few - I bought a bunch of capacitors to try to some thin foil but all the different types I got were thicker than aluminium foil. I got low voltage, high voltage, low capitance and high capitance - all the same. Anyone got tips on what capacitors have the right foil?
Cheers
Andrew
The fuzzy picture is couresy of the iPhone and it's lack of any autofocus. I'll take some better pictures soon - When I've sorted a better ribbon mounting setup as there's no real point now.
Few - I bought a bunch of capacitors to try to some thin foil but all the different types I got were thicker than aluminium foil. I got low voltage, high voltage, low capitance and high capitance - all the same. Anyone got tips on what capacitors have the right foil?
Cheers
Andrew
Picture of the "Artwork Knife" from Jaycar electronics I pulled off the corrugated section (20mm wide) and used it to put the pleats in the foil. I plan to make up a rig to feed ribbon through for quick and consistent ribbons.
CAT. NO. HG9955
http://www.jaycar.com.au/productView.asp?ID=HG9955
CAT. NO. HG9955
http://www.jaycar.com.au/productView.asp?ID=HG9955
Attachments
Hi Andrew,
Why yes I do
These are the ones I found that work a treat. 6-7 micron, and fairly easy to harvest. I can get 4) 60"x 3/4" out of one. I'd email the guy, I'm sure he would ship across the pond...
http://cgi.ebay.com/12-Pcs-Cornell-...ryZ14977QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
As a bonus, they are very nice caps.
Casey
Edit: I forgot to mention that these look nice..great project
Why yes I do
These are the ones I found that work a treat. 6-7 micron, and fairly easy to harvest. I can get 4) 60"x 3/4" out of one. I'd email the guy, I'm sure he would ship across the pond...http://cgi.ebay.com/12-Pcs-Cornell-...ryZ14977QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
As a bonus, they are very nice caps.
Casey
Edit: I forgot to mention that these look nice..great project
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