dhenryp said:
Denis,
Thanks for the compliment, It is a Barco 1208 CRT projector. You can see it in this picture A bit old, but easily does 1280x720p for DVD and 1080i for HDTV. It has even been color corrected...and color temperature calibrated. The picture outdoes anything you can see at Circuit-City/Best-Buy, etc... not bad for a projector manufactured 10 years ago. 😀 Just need to have a very understanding wife and secure the projector well to the ceiling. The Barco projector weighs 185 lbs. DIY projector mounting bracket - made of unistrut and 3/8th inch threaded rod.
tiroth said:
tiroth,
Vertical orientation is certainly something I need to think about. It would be much easier physically to have one 6-7" ribbon flanked by two decent midwoofers. I don't really need frequency response much below 80Hz where I have my crossover for the sub set. I wonder if I could even go 10" with a DIY vertical ribbon. (Denis used three magnets per side, perhaps 4 would be a nice compromise to get the crossover point a bit lower) Lots of room for experimentation.
Joe L.
(Isn't DIY fun 😀)
J. L. said:
I actually visited Barco headquarters on business once, quite a place. Personally I'm a horrible tweaker, I must refocus my projector three or four times during a movie, it drives my daughter nuts. I always figured out that if I had a three projector setup I would try to reconverge it every night.
Member
Joined 2003
Denis,
Noticed you haven't posted in a while. How are you progressing with your line arrays?
I still have a lot of baffle work to do, but the end goal is in sight. Here is a shot of a "minimum diffraction" baffle and single element 1"x45" motor (shown here with abused ribbon)...sure glad the design provides for ribbon replacement with the motor mounted in the baffle!
Paul
Noticed you haven't posted in a while. How are you progressing with your line arrays?
I still have a lot of baffle work to do, but the end goal is in sight. Here is a shot of a "minimum diffraction" baffle and single element 1"x45" motor (shown here with abused ribbon)...sure glad the design provides for ribbon replacement with the motor mounted in the baffle!
Paul
An externally hosted image should be here but it was not working when we last tested it.
Hi Paul,
What a beautiful speaker! I would love to get a closer look at your ribbon. What kind of veneer are you using on the baffle? Looks like it might be maple or quarter sawn white oak.
My arrays are coming along. I worked on them this weekend and completed the basic boxes and bracing. I still have 28 speaker holes to route. I'm going to try veneering with raw veneer for the first time. Realistically, I probably have another 4-6 weeks before the speakers are veneered with all drivers installed and wired. I still haven't decided if I will try a simple temporary passive crossover or go directly to an active with DIY amps. The former might only add another month or so, the active setup could 2 months to 2 years (I hope I'm only joking about that). How close are you to finishing? You look pretty close.
It looks like my arrays are kind of the opposite design approach to yours. Yours are open baffle with pretty wide wings and two pretty big mid-woofs (are you going to use the Seas driver from your last speaker?). My arrays are closed back with narrow baffles (my speakers have to fit in pretty narrow spaces on either side of a HT screen). I'm also using a lot of small (4.5") mid-woofs. There are many ways to skin this cat (sorry PETA).
Regards,
Denis
What a beautiful speaker! I would love to get a closer look at your ribbon. What kind of veneer are you using on the baffle? Looks like it might be maple or quarter sawn white oak.
My arrays are coming along. I worked on them this weekend and completed the basic boxes and bracing. I still have 28 speaker holes to route. I'm going to try veneering with raw veneer for the first time. Realistically, I probably have another 4-6 weeks before the speakers are veneered with all drivers installed and wired. I still haven't decided if I will try a simple temporary passive crossover or go directly to an active with DIY amps. The former might only add another month or so, the active setup could 2 months to 2 years (I hope I'm only joking about that). How close are you to finishing? You look pretty close.
It looks like my arrays are kind of the opposite design approach to yours. Yours are open baffle with pretty wide wings and two pretty big mid-woofs (are you going to use the Seas driver from your last speaker?). My arrays are closed back with narrow baffles (my speakers have to fit in pretty narrow spaces on either side of a HT screen). I'm also using a lot of small (4.5") mid-woofs. There are many ways to skin this cat (sorry PETA).
Regards,
Denis
Member
Joined 2003
Hi Denis,
The baffles are golden anegre. I pulled the second one out of the jig this weekend, so both are now in the same state. I like the look without a base, but they will be 200 lbs and front-heavy...so I need to be 210% sure they cannot tip forward on dogs, kids, etc. Other than adding bases, I don't have that much to do, but won't be able to work on them at all for a couple of weeks...so we're on roughly the same timetable.
Yes, I am re-using the Seas W26's...very pleased with them. The W22 is actually my favorite driver in the "mules" but, since the big ribbon will allow a crossover below 600Hz, I think the best crossover is no crossover 🙂...so the W22's will go on the shelf for another day.
Your crossover choice is interesting...active is quick and easy, but passive is more fun. The mules have two passives and one active. The active and one passive took about an hour each, but it took me a year of tweaking (interupted by many pleasant hours of listening) the to finally get the passive D76/OW1 right.
Paul
The baffles are golden anegre. I pulled the second one out of the jig this weekend, so both are now in the same state. I like the look without a base, but they will be 200 lbs and front-heavy...so I need to be 210% sure they cannot tip forward on dogs, kids, etc. Other than adding bases, I don't have that much to do, but won't be able to work on them at all for a couple of weeks...so we're on roughly the same timetable.
Yes, I am re-using the Seas W26's...very pleased with them. The W22 is actually my favorite driver in the "mules" but, since the big ribbon will allow a crossover below 600Hz, I think the best crossover is no crossover 🙂...so the W22's will go on the shelf for another day.
Your crossover choice is interesting...active is quick and easy, but passive is more fun. The mules have two passives and one active. The active and one passive took about an hour each, but it took me a year of tweaking (interupted by many pleasant hours of listening) the to finally get the passive D76/OW1 right.
Paul
Wow this is pretty cool...
not to hijack your thread Dhenry... but I have a few questions before I attempt this myself in a few days...
I'm using that site you used Dhenry for magnets but instead of the magnets you used I'm use the .25" wide x .5" tall x .75" long magnets.... that would give me the larger magnetic depth (larger field) and it's only 40 cents more per 1.5" of magnets along the .5" steel
Also I've been trying to use FEMM but it just doesn't click in my brain.
I don't like to ask for help and ask modeling favors but could someone calculate the telsa for a 1.5" long x .5" wide x .5" deep neo magnet.
Also the gap will only be .25" because I only need the tweet to go to 2khz or 2.5khz or so... but highly efficent
FINAL question....
My design is like Dhenry's but it's 81" long and is split every 6" into sections, so around 13 sections... I'm using 1/2 inch steel to seperate
the MAIN difference between mine and Dhenry's is that instead of Series all the ribbon sections I want to parallel them to gain electrical efficency
I believe that using this design would yield around 112 db efficency
I just want to run that design buy you guys... I just need help figuring out the telsa and the efficency for EACH 6" section.... so that I can create a transformer
Congrats BTW to Dhenry... that DIY step by step guide is AMAZING...
I also will offer step by step instructions with some pics as my progress with the test 6" ribbon progresses
not to hijack your thread Dhenry... but I have a few questions before I attempt this myself in a few days...
I'm using that site you used Dhenry for magnets but instead of the magnets you used I'm use the .25" wide x .5" tall x .75" long magnets.... that would give me the larger magnetic depth (larger field) and it's only 40 cents more per 1.5" of magnets along the .5" steel
Also I've been trying to use FEMM but it just doesn't click in my brain.
I don't like to ask for help and ask modeling favors but could someone calculate the telsa for a 1.5" long x .5" wide x .5" deep neo magnet.
Also the gap will only be .25" because I only need the tweet to go to 2khz or 2.5khz or so... but highly efficent
FINAL question....
My design is like Dhenry's but it's 81" long and is split every 6" into sections, so around 13 sections... I'm using 1/2 inch steel to seperate
the MAIN difference between mine and Dhenry's is that instead of Series all the ribbon sections I want to parallel them to gain electrical efficency
I believe that using this design would yield around 112 db efficency
I just want to run that design buy you guys... I just need help figuring out the telsa and the efficency for EACH 6" section.... so that I can create a transformer
Congrats BTW to Dhenry... that DIY step by step guide is AMAZING...
I also will offer step by step instructions with some pics as my progress with the test 6" ribbon progresses
Hi Audiophilenoob,
The magnetic gap field strength will depend upon many design decisions. Dhenry mentioned in this thread that adding rear cross braces to his frame increased the field strength by 40%. There are FEMM users groups that can answer questions you may have about the program. FEMM is worth the time to learn.
If you put several very short ribbons in parallel the final resistance will be so low that it would be almost impossible to buiild a step-up transformer. Dhenery used a series connection for this reason. You will also have comb filtering effects with multiple short tweeter ribbons. There are several papers on the web describing and calculating comb filtering.
Instead of multiple 6" ribbon segments, consider building one continuous 81" tweeter ribbon with a few dabs of silicone in the ribbon-magnet gap to matain spacing, and control resonance and air puff damage. If you look back over this thread you will see diagrams of the Magnepan tweeter and some discussion of how to use sims when you install the ribbon and dots of adhesitve in the gap. For the long foil you can open up a film/foil capacitor. You can use cooking aluminum foil to practice cutting and corrugating the ribbon.
Based upon your magnet strength, motor design, and foil thickness, an 81" x 0.25" tweeter ribbon efficiency could range from 90 to 103 db/watt.
The magnetic gap field strength will depend upon many design decisions. Dhenry mentioned in this thread that adding rear cross braces to his frame increased the field strength by 40%. There are FEMM users groups that can answer questions you may have about the program. FEMM is worth the time to learn.
If you put several very short ribbons in parallel the final resistance will be so low that it would be almost impossible to buiild a step-up transformer. Dhenery used a series connection for this reason. You will also have comb filtering effects with multiple short tweeter ribbons. There are several papers on the web describing and calculating comb filtering.
Instead of multiple 6" ribbon segments, consider building one continuous 81" tweeter ribbon with a few dabs of silicone in the ribbon-magnet gap to matain spacing, and control resonance and air puff damage. If you look back over this thread you will see diagrams of the Magnepan tweeter and some discussion of how to use sims when you install the ribbon and dots of adhesitve in the gap. For the long foil you can open up a film/foil capacitor. You can use cooking aluminum foil to practice cutting and corrugating the ribbon.
Based upon your magnet strength, motor design, and foil thickness, an 81" x 0.25" tweeter ribbon efficiency could range from 90 to 103 db/watt.
Hi Audiophilenoob,
I agree with linesource and have a couple additional comments/questions:
1. I assume you are talking about the Rect0750 magnets here:
http://www.engconcepts.net/List_Of_Rectangle_Magnets.asp
These are exactly the same as the magnets I used (Rect1750) except yours are half the length. The only way to get the .5" thickness you mentioned would be to use a double layer. Was that your intent?
I'll help you with a femm simulation of your situation but first let me know if you intend .5" thick or .25" thick magnets.
I agree with linesource that segmented ribbons will have some comb filtering effect but it should be no worse than the many line arrays that use multiple 5-6" planars (like PT2s). My segments are separated by 1.5" but only once every 7.25 ". It is different than having a series of circular tweeters each with a 1.5" spacing. I've not seen an analysis that predicts the amount of comb filtering in my case.
Thanks for the complement. I'm glad this has helped you.
Regards,
Denis
I agree with linesource and have a couple additional comments/questions:
1. I assume you are talking about the Rect0750 magnets here:
http://www.engconcepts.net/List_Of_Rectangle_Magnets.asp
These are exactly the same as the magnets I used (Rect1750) except yours are half the length. The only way to get the .5" thickness you mentioned would be to use a double layer. Was that your intent?
I'll help you with a femm simulation of your situation but first let me know if you intend .5" thick or .25" thick magnets.
I agree with linesource that segmented ribbons will have some comb filtering effect but it should be no worse than the many line arrays that use multiple 5-6" planars (like PT2s). My segments are separated by 1.5" but only once every 7.25 ". It is different than having a series of circular tweeters each with a 1.5" spacing. I've not seen an analysis that predicts the amount of comb filtering in my case.
Thanks for the complement. I'm glad this has helped you.
Regards,
Denis
Hi Linesource and Dhenry,
The magnets are the Rect0750 each one is .75"x.5"x.25 the are .5" THICK .25" wide... magnetized through thickness I believe
4 are used for each side every 1.5"
Linesource... could I create 13 seperate transformers??? then wire them in parallel?
I need a high high efficency solution... to match the 113db of midranges I will have for my array
Could I not do a very large transformer for the all parallel 13 sections like I wanted???
I don't really care about minor vertical dispersion problems... a uber efficency is far more important... plus many many people place small (6" or so) ribbons in a row for a line array...
Also I will have cross bracings as well.. only 1" or .5" wide steel.
Thanks everyone
I will try to work with FEMM some more... it's just really too much for my brain (haven't touched math in years)
The magnets are the Rect0750 each one is .75"x.5"x.25 the are .5" THICK .25" wide... magnetized through thickness I believe
4 are used for each side every 1.5"
Linesource... could I create 13 seperate transformers??? then wire them in parallel?
I need a high high efficency solution... to match the 113db of midranges I will have for my array
Could I not do a very large transformer for the all parallel 13 sections like I wanted???
I don't really care about minor vertical dispersion problems... a uber efficency is far more important... plus many many people place small (6" or so) ribbons in a row for a line array...
Also I will have cross bracings as well.. only 1" or .5" wide steel.
Thanks everyone
I will try to work with FEMM some more... it's just really too much for my brain (haven't touched math in years)
Hi Audiophilenoob,
I'm pretty sure you are mistaken about the magnets. If you look at the picture (I've attached it) you can see the magnets are attached at the .5 X .75" side. This would only happen if these are the poles.
Attempting to connect the ribbon in parallel (with or without separate transformers) will not get you any more efficiency. You can design your transformer to present as much or as little impedance as you want by changing the turn ratio.
The only ways to increase efficiency are:
1. Increase the field strength with stronger (neodymium goes up to N50 if you are willing to pay enough) or thicker magnets. You can get large blocks of neodymium but it gets pretty expensive, pretty quick with an 81" length.
2. Increase the ribbon area. I don't know if it's practical to make it much longer than 81". You could make the ribbon wider but unless you keep the field strength the same (with more powerful magnets) you will lose exactly as much efficiency in field strength as you gain in area.
3. You can reduce the mass of the ribbon. I'm using relatively thick foil. linesource uses foil about half as thick. It is not easy to get much thinner than that.
What midrange drivers are you using to get 113 db? Are you positive you can get that? It is very high.
If you you do need more power out of you ribbon than efficiency will allow with a passive crossover you could always go active. This would allow you to match power amp sizes to get the right balance.
Regards,
Denis
I'm pretty sure you are mistaken about the magnets. If you look at the picture (I've attached it) you can see the magnets are attached at the .5 X .75" side. This would only happen if these are the poles.
Attempting to connect the ribbon in parallel (with or without separate transformers) will not get you any more efficiency. You can design your transformer to present as much or as little impedance as you want by changing the turn ratio.
The only ways to increase efficiency are:
1. Increase the field strength with stronger (neodymium goes up to N50 if you are willing to pay enough) or thicker magnets. You can get large blocks of neodymium but it gets pretty expensive, pretty quick with an 81" length.
2. Increase the ribbon area. I don't know if it's practical to make it much longer than 81". You could make the ribbon wider but unless you keep the field strength the same (with more powerful magnets) you will lose exactly as much efficiency in field strength as you gain in area.
3. You can reduce the mass of the ribbon. I'm using relatively thick foil. linesource uses foil about half as thick. It is not easy to get much thinner than that.
What midrange drivers are you using to get 113 db? Are you positive you can get that? It is very high.
If you you do need more power out of you ribbon than efficiency will allow with a passive crossover you could always go active. This would allow you to match power amp sizes to get the right balance.
Regards,
Denis
dhenryp said:
I'm using 12 Audax PR170 (I think that's the code) 6.5" midranges... they are 100 db at 1w/m each... you have added acoustical and electrical efficency (they will be wired to a 3 ohm line so around 3 db added for that)
I am going active so that step is taken care of...
I don't need to go wider on the ribbon cause I only need it to go down to 2khz... unless that width added efficency I don't see a point... I wanted to shorten the gap so that efficency would increase with smaller magnets
I see now... I guess you are right about the magnets... either way I guess it doesn't matter as I can just stack them instead of side by side....
I don't wanna level the PR's down... I bought the high efficency midranges to use them....
why will connecting them in parallel not give me the electrical efficency? I don't understand that
I know that ribbons don't add driver efficency but electrical efficency still comes into play...
If I paralleled them it would be 10log(whatever ohm load per 6" ribbon/final ohm load of line)....
it gives you 13 dbs extra added efficency
Hi Audiophilenoob,
The only way you get more power out of speakers by putting multiple drivers in parallel is by reducing the total impedance presented to the amplifier. Since you amplifier has a fixed power supply voltage, cutting driver impedance in half will double the power sent to the driver (assuming the amplifier can actually deliver the extra current).
In the case of a ribbon with an impedance matching transformer, you can change the impedance presented to the amplifier to whatever you want by changing the transformer turns ratio. In my case I have seven segments in series and I've wound the transformer to present a nominal 8 ohms. I could change the impedance to 4 or 16 (or any other value) by changing the turns ratio. Unless you have have a super high current/low voltage amplifier built to handle very low impedance, you typically don't need to have a very low impedance.
The limiting factor will be how much current your ribbons can handle and how much current the transformer can handle without saturating. The only time it would be an advantage to use multiple transformers is if you needed to to deliver more total power than one transformer core could handle. In that case it should be possible to connect segments to different transformers.
How much power are you planning on sending to your ribbons? Even if you "only" got 100 db/watt efficiency (not a minor accomplishment), a ten what amp would give you an output of 110db. Forty watts would give you an additional 6 db. 110 or 116b db is VERY loud. Unless you are using your ribbons in something the size of a cathedral it's hard to imagine you could ever use more high frequency energy without physical damage to your ears.
Similarly, if you have 113 db mid/woofer sensitivity, with only a 10 watt amplifier that would get you 123 db! That is much more than a human can stand without permanent damage. 100 watts (which 12 6.5" drivers could easily handle) would theoretically produce 133 db which does not even sound like a possible sound level.
It seems that unless you are driving your mids and ribbons with flea-power SET triode amps, the super high efficiency is of little real practical use.
I don't want to be too negative. It sounds like you have the makings of a great line array reagrdless of the efficiency you get. I'm also alway happy to see somebody else try a DIY ribbon.
Regards,
Denis
The only way you get more power out of speakers by putting multiple drivers in parallel is by reducing the total impedance presented to the amplifier. Since you amplifier has a fixed power supply voltage, cutting driver impedance in half will double the power sent to the driver (assuming the amplifier can actually deliver the extra current).
In the case of a ribbon with an impedance matching transformer, you can change the impedance presented to the amplifier to whatever you want by changing the transformer turns ratio. In my case I have seven segments in series and I've wound the transformer to present a nominal 8 ohms. I could change the impedance to 4 or 16 (or any other value) by changing the turns ratio. Unless you have have a super high current/low voltage amplifier built to handle very low impedance, you typically don't need to have a very low impedance.
The limiting factor will be how much current your ribbons can handle and how much current the transformer can handle without saturating. The only time it would be an advantage to use multiple transformers is if you needed to to deliver more total power than one transformer core could handle. In that case it should be possible to connect segments to different transformers.
How much power are you planning on sending to your ribbons? Even if you "only" got 100 db/watt efficiency (not a minor accomplishment), a ten what amp would give you an output of 110db. Forty watts would give you an additional 6 db. 110 or 116b db is VERY loud. Unless you are using your ribbons in something the size of a cathedral it's hard to imagine you could ever use more high frequency energy without physical damage to your ears.
Similarly, if you have 113 db mid/woofer sensitivity, with only a 10 watt amplifier that would get you 123 db! That is much more than a human can stand without permanent damage. 100 watts (which 12 6.5" drivers could easily handle) would theoretically produce 133 db which does not even sound like a possible sound level.
It seems that unless you are driving your mids and ribbons with flea-power SET triode amps, the super high efficiency is of little real practical use.
I don't want to be too negative. It sounds like you have the makings of a great line array reagrdless of the efficiency you get. I'm also alway happy to see somebody else try a DIY ribbon.
Regards,
Denis
dhenryp said:
I was planning on 10-30 watts per ribbon... unsure on the exact amount ... it can be any number as I'm probably gonna get a custom low impedence Class A amp...
The super high efficency of the midranges isn't the important selling point that made me buy them... they are one of the best midranges period.... Also I've already had my low efficency array, I want something different...
I just want this array to be the best of the best....
I think you misunderstand what paralleling does when you put drivers like that
take 10 NeoCD5i's and parrallel them all together... you have 111 or so db efficency.... so it seems that that high efficency can be created with either 13 individual transformers, or one huge transformer...
What the new setup will contain... per side is:
5 15" Lambda TD15H or 15x's
10-12 AUDAX PR170MO
then this ribbon....
all active...
I just need help figuring several things... linesource can help me figure out the resistance of a 6" piece of aluminum that's .25" wide and 12.5 microns thick (0.005")...
if going thinner will help I will try to find a source for aluminum... but I need to figure out the telsa and final resistance per 6" section....
this is possible correct?... or am I overshooting here?
Audiophilenoob,
One continuous 81" ribbon will be superior in sound and easier to construct than multiple 6" ribbons. Cut open a few different film/foil capacitors to search for thin aluminum foil. Experiment by cutting your first ribbons from a $2 box of household foil.
The speaker industry uses both Efficiency and Sensitivity
Efficiency = SPL db/m at 1 watt
Sensitivity = SPL db/m at 2.83 volts input (1 watt into 8 ohms)
When you double the number of speakers you increase Efficiency by 3db from the doubling in area. If you wire the 2 speakers in parallel and have an amplifier that can deliver 2x current into 1/2 resistance, then the Sensitivity increases by 6db, from 2x area * 1/2 resistance.
You will start to lose hearing at 85db continuous listening. I usually design my speakers not to self destruct at 110 db @ 1m. Most of my daily listening is below 75db at the listening position, with a few 90 db short peaks.
------------------- Using some simple spreadsheet models---------
12.7 microns = 0.0005 inches thickness
81" long 0.25" wide (89" length with corrugations and attachments)
0.74 ohms
0.49 grams
1 Tesla magnetic field
Efficiency = 97.6 db/m @ 1 watt
Sensitivity = 98.6 db/m @ 2.83 volts
6" long 0.25" wide (6.6 with corrugations and attachments)
0.055 ohms
0.037 grams
1 Tesla magnetic field
Efficiency = 86.3 db/m @ 1 watt
Sensitivity = 88.5 db/m @ 2.83 volts
One continuous 81" ribbon will be superior in sound and easier to construct than multiple 6" ribbons. Cut open a few different film/foil capacitors to search for thin aluminum foil. Experiment by cutting your first ribbons from a $2 box of household foil.
The speaker industry uses both Efficiency and Sensitivity
Efficiency = SPL db/m at 1 watt
Sensitivity = SPL db/m at 2.83 volts input (1 watt into 8 ohms)
When you double the number of speakers you increase Efficiency by 3db from the doubling in area. If you wire the 2 speakers in parallel and have an amplifier that can deliver 2x current into 1/2 resistance, then the Sensitivity increases by 6db, from 2x area * 1/2 resistance.
You will start to lose hearing at 85db continuous listening. I usually design my speakers not to self destruct at 110 db @ 1m. Most of my daily listening is below 75db at the listening position, with a few 90 db short peaks.
------------------- Using some simple spreadsheet models---------
12.7 microns = 0.0005 inches thickness
81" long 0.25" wide (89" length with corrugations and attachments)
0.74 ohms
0.49 grams
1 Tesla magnetic field
Efficiency = 97.6 db/m @ 1 watt
Sensitivity = 98.6 db/m @ 2.83 volts
6" long 0.25" wide (6.6 with corrugations and attachments)
0.055 ohms
0.037 grams
1 Tesla magnetic field
Efficiency = 86.3 db/m @ 1 watt
Sensitivity = 88.5 db/m @ 2.83 volts
LineSource said:
thanks for that info linesource
86.3 is poor. what if I did .5" wide, and used 5.8 micron foil? would that increase efficency.
I know that doing one long line would be superior... but how could I get 105 db+ efficency unless I parallel them all?
I know I don't NEED that much... but because I want this to be so uber efficent it seems the only option
the efficency is to match the high efficency midranges and midbasses
Ideally I would like to reproduce the Neo5CDi...
http://www.madisound.com/cgi-bin/index.cgi?cart_id=6518152.8111&pid=1891
it has a one telsa gap over around .6" wide aluminum... it's a 5.7" long ribbon...
it looks to me like they use a very wide magnet like instead of .5" wide like Dhenry did... they used probably an inch depth in their steel....
At the very least I would like to copy the Neo2... 0.6 telsa field... .3" wide aluminum
or if possible... ideally... reproduce the Raven 3.1 ribbon...
it has a 1 telsa field, and only a 0.035g ribbon... but 2400 mm^2 of ribbon
I really only need a 95 db/m efficency per ribbon segment... I don't need that 100 db sensitivity, or like the Neo5d, 102 db....
Thanks guys for the help
http://www.madisound.com/cgi-bin/index.cgi?cart_id=6518152.8111&pid=1891
it has a one telsa gap over around .6" wide aluminum... it's a 5.7" long ribbon...
it looks to me like they use a very wide magnet like instead of .5" wide like Dhenry did... they used probably an inch depth in their steel....
At the very least I would like to copy the Neo2... 0.6 telsa field... .3" wide aluminum
or if possible... ideally... reproduce the Raven 3.1 ribbon...
it has a 1 telsa field, and only a 0.035g ribbon... but 2400 mm^2 of ribbon
I really only need a 95 db/m efficency per ribbon segment... I don't need that 100 db sensitivity, or like the Neo5d, 102 db....
Thanks guys for the help
I found a supplier in india that has 5 micron foil at any width and length...
I'm thinking about ordering a 100 foot roll at .5" wide...
if I need to increase the magnetic field I COULD double stack the magnets.... so instead of .5" thick on the magnets (two stacked like I said) I could do 1" thick (4 stacked)...
Also sectioning it like Dhenry did would increase the magnetic field like Linesource suggested...
I'm not exactly sure how much it would take to make a 1 telsa gap over .5" width..
I'm thinking about ordering a 100 foot roll at .5" wide...
if I need to increase the magnetic field I COULD double stack the magnets.... so instead of .5" thick on the magnets (two stacked like I said) I could do 1" thick (4 stacked)...
Also sectioning it like Dhenry did would increase the magnetic field like Linesource suggested...
I'm not exactly sure how much it would take to make a 1 telsa gap over .5" width..
A fly on the wall
I'm a watchin cause I think a 7' ribbon is a good idea to. Keep it up Gents there is a lot to be learned in this thread. Your thoughts are appreciated by al.
MArk
I'm a watchin cause I think a 7' ribbon is a good idea to. Keep it up Gents there is a lot to be learned in this thread. Your thoughts are appreciated by al.
MArk
Sorry for the High jack
Linesource
Are you really building the ribbons you mention in the low impedance Class D thread? And if so could you give some info?
Maybe in another thread or privately so as to not infringe on this discussion.
mwmkravchenko@hotmail.com
Mark
Linesource
Are you really building the ribbons you mention in the low impedance Class D thread? And if so could you give some info?
Maybe in another thread or privately so as to not infringe on this discussion.
mwmkravchenko@hotmail.com
Mark