Phase 2
I have gone on to using the Bag End 10" coaxial in place of the RCF and B&C midrange and treble drivers.
The Bag End is 98 db/watt 8 ohm with a curvalinear cone. I modified it by removing the dustcap and extending the concentric horn out past the woofer surround with a small conical round horn. The lower bass is the same but I have made the bass and upper section seperate to experiment with different upper range drivers.
The coax is now coming in at 150 cycles and crossed at 3K on the top. The added conical horn loads the Emilar 175 1" compression driver well below that and is also acting as a phase plug for the cone. The baffle is larger than before.
The sound before was like a good pair of Sennheiser headphones. With the modded coax it is now on the level of the upper end Stax electrostatic headphones! Transparent, detailed and natural.
Massed strings have more life and are layered back through the stage projecting with both the sheen and sweetness of the real thing, vocals are more alive and palatable. Instruments are 'staying in place' more and are more dimensional and distinct through their fundamentals. Bowed upright bass is SCARY as wll as cellos - Overall the tone has leaped forward with more vibrant colors yet sound more natural and relaxed. The sweet spot has opened up in all dimensions.
The dynamics are also spectacular. IE listening to a drum set or highly percussive recordings explode with more precision and cohesion. More 'whole' and real. -- They are here - like a good multi-horn system but virtually no coloration or beam. SNAP = SNAP.
I have gone on to using the Bag End 10" coaxial in place of the RCF and B&C midrange and treble drivers.
The Bag End is 98 db/watt 8 ohm with a curvalinear cone. I modified it by removing the dustcap and extending the concentric horn out past the woofer surround with a small conical round horn. The lower bass is the same but I have made the bass and upper section seperate to experiment with different upper range drivers.
The coax is now coming in at 150 cycles and crossed at 3K on the top. The added conical horn loads the Emilar 175 1" compression driver well below that and is also acting as a phase plug for the cone. The baffle is larger than before.
The sound before was like a good pair of Sennheiser headphones. With the modded coax it is now on the level of the upper end Stax electrostatic headphones! Transparent, detailed and natural.
Massed strings have more life and are layered back through the stage projecting with both the sheen and sweetness of the real thing, vocals are more alive and palatable. Instruments are 'staying in place' more and are more dimensional and distinct through their fundamentals. Bowed upright bass is SCARY as wll as cellos - Overall the tone has leaped forward with more vibrant colors yet sound more natural and relaxed. The sweet spot has opened up in all dimensions.
The dynamics are also spectacular. IE listening to a drum set or highly percussive recordings explode with more precision and cohesion. More 'whole' and real. -- They are here - like a good multi-horn system but virtually no coloration or beam. SNAP = SNAP.
Dragging out the "skin effect"
The real question is how does skin effect have any relevance at such low frequencies (20,000 Hz and lower)?
Please "do the math yourself" and then decide if this argument makes sense. At 10Khz the skin depth in copper is 28 mils... not likely be of any significance in somnething less than 1/10th as thick
http://www.microwaves101.com/encyclopedia/calsdepth.cfm
I suspect proponents of "skin effect" are grasping at some sort of scientific explanation for a deficiency in their explanation and perceptions, and "skin effect' seems to be a convenient phenomenon to use.
I also suspect that what they're really talking about is (or is analogous to) "terminal effect", wherein ultra thin conductors have weird current distribution through them for various reasons... can and does occur down to dc for thin films & structures, and causes all sorts of mayhem in the electroplating industry (pc board metal distribution, rapid plating of terminal strips, lead frames, etc with gold, etc.) among others.
I designed and built what we called a "tunable bridge strongback" back in 1984 when we were electroforming ink-jet orifice plates on 3 mil stainless steel strips 5 feet long with 6,000 3 mil holes for the spray nozzle. We electroformed Nickel/phosphorous alloy over a linear array of 6000 .003" photoresist pegs until we got the final diameter of ~.0025", and they had to all be the same within +/- .5 micron. This was exquisitly sensitive to current density variations in the stainless strip (at dc) so we controlled that by running a variable constant current feed at 200 strategic connections along the strip, thus varying the current to 30 pegs per connection as determined from flow tests and microscope readings.
Skin effect? Nope... terminal effect... maybe....
I'd also suspect the "micro-drumhead resonance theory" w/o some sort of interferometric demonstration of its existance.
John L.
Pan said:
The real question is how does skin effect have any relevance at such low frequencies (20,000 Hz and lower)?
Please "do the math yourself" and then decide if this argument makes sense. At 10Khz the skin depth in copper is 28 mils... not likely be of any significance in somnething less than 1/10th as thick
http://www.microwaves101.com/encyclopedia/calsdepth.cfm
I suspect proponents of "skin effect" are grasping at some sort of scientific explanation for a deficiency in their explanation and perceptions, and "skin effect' seems to be a convenient phenomenon to use.
I also suspect that what they're really talking about is (or is analogous to) "terminal effect", wherein ultra thin conductors have weird current distribution through them for various reasons... can and does occur down to dc for thin films & structures, and causes all sorts of mayhem in the electroplating industry (pc board metal distribution, rapid plating of terminal strips, lead frames, etc with gold, etc.) among others.
I designed and built what we called a "tunable bridge strongback" back in 1984 when we were electroforming ink-jet orifice plates on 3 mil stainless steel strips 5 feet long with 6,000 3 mil holes for the spray nozzle. We electroformed Nickel/phosphorous alloy over a linear array of 6000 .003" photoresist pegs until we got the final diameter of ~.0025", and they had to all be the same within +/- .5 micron. This was exquisitly sensitive to current density variations in the stainless strip (at dc) so we controlled that by running a variable constant current feed at 200 strategic connections along the strip, thus varying the current to 30 pegs per connection as determined from flow tests and microscope readings.
Skin effect? Nope... terminal effect... maybe....
I'd also suspect the "micro-drumhead resonance theory" w/o some sort of interferometric demonstration of its existance.
John L.
Re: Re: Re: Phase 2
No way, see below -----
You are so correct!
I will post pictures of this coax soon.
These are getting close to my 'Stargate' class of speakers, I have one other idea to try before I officially classify the speaker as the 'Stargate FFB' or Free From Box .
Russell Dawkins said:
No way, see below -----
badman said:
Not terribly likely- magnetar will be through about 300 new iterations in the next 2 years)
Settling on a single design doesn't seem to be one of his strong points
You are so correct!
I will post pictures of this coax soon.
These are getting close to my 'Stargate' class of speakers, I have one other idea to try before I officially classify the speaker as the 'Stargate FFB' or Free From Box .
SunRa said:
It's coming along! With the high pass (these are triamped) set at 150 HZ it's easily capable of a clean 120 db.
Bag End
An externally hosted image should be here but it was not working when we last tested it.
The un-modified coax used with 3 other tens for guitar. I'm unsure what compression driver is used in the factory speaker. The one with the red dust cap is the coax. They set the crossover at 3.6 k . It is the driver E-10X. The factory horn is a conical throat and ends with a stub behind the dust cap. I added a conical extension and use an aluminum 1.75" diaphragm compression driver with mylar surround versus the titanium they use. With the added extension the drivers blend better in the upper midrange low treble and can be crossed over lower. The cone driver itself is quite linear and efficient. I'm not sure of the origin of the driver but with it's cast frame and large magnet it appears to be quite a step up from Eminence Beta 10CX. They show up on ebay occasionally with no compression driver or can be bought directly from Bag End as replacement drivers.
Well, I have to say the coaxials were wearing on me quick -- too much hifi - too much like good headphones, too much like 'high end' audio -
I decided to pull out my large format Emilar compression drivers in 300 HZ tractrix round horns and hook them to my 45 amps, I set them on top of the OB bass and crossed at 500 HZ - I'm back to square one on this one.
Maybe Klangfilm had it right 50 years ago.
I decided to pull out my large format Emilar compression drivers in 300 HZ tractrix round horns and hook them to my 45 amps, I set them on top of the OB bass and crossed at 500 HZ - I'm back to square one on this one.
Maybe Klangfilm had it right 50 years ago.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
winslow said:
I saw where you can mod the BMS and get better sound. Here is another Eurodyn, they are built into the smaller baffle and the larger (wood grain) baffle is surrounding it and not attached . They do this so the big boards don't resonate. I'm thinking of using 6 of the madison woofers per side up to 120 cycles then two of the hemp eminence lil buddies 120 to 600 and the emilar 320 from 600 up. LOL, that should move some air with better tone (no irritating hifi precision I seem to be digging myself into) then what I've been listening to. I can use my little direct heated amps from 120 up and still drive the room with authority and no bass horns.. LOL
What do you think?
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