Well they even have a beer named after a mudshark. Maybe you could get the Fish Brewery to be your corporate sponsor...
Fish Brewing Company, Olympia, WA » Home
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the fish speaker looks like a cool project, where could i find more info about it?
Matt
Wholeheartedly agreed.
Toole's book is a must read. I own both, and the complement each other nicely.
See it here on Amazon:
http://www.amazon.com/Sound-Reproduction-Acoustics-Psychoacoustics-Loudspeakers/dp/0240520092/ref=cm_cr_pr_product_top
And see Geddes' here on his website:
Home Theater
Transducers
Anand.
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Sorry if this is has already been pointed out.
I agree with you that a fan blade moving at constant velocity in one direction (and hence also constant force) will perform equally as well regardless of material.
But a speaker cone does not move at constant velocity, with constant direction (ie constant force).
Even a perfect sine wave of a single test tone is not constant velocity because the speaker cone is constantly changing direction, and the change of displacement with respect to time is also changing. Therefore the force applied to the speaker cone is changing (ie cyclic loading).
Obviously music is a lot more dynamic (ie the amplitude of sound waves are always changing) as well as complex (more than one frequency is heard at any one time). So the problem is significantly worse for reproducing music than it is for a simple test tone.
So this is where hysteresis becomes important. When a material is subjected to constant force (eg fan blade) the effect of hysteresis is nill.
However when you apply a cyclic load to a material, hysteresis is observed. Different materials display different amounts of hysteresis.
To keep it simple hysteresis is bad. Hysteresis means energy loss. This means distortion.
To reduce the effect of hysteresis you can either use a different material, eg metals have much lower (almost negligible) hysteresis when used in their elastic zone compared to plastics, or you can make a composite material eg various coatings, fibre reinforced materials, etc.
I am not sure how significant or audible these effects will be on a speaker cone while reproducing music, but they will be present none the less.
So now we come to the catch 22. If we reduce the hysteresis to zero the resonances which Charles talks about will be even worse because there will be no hysteresis to dampen the resonances. Resonances can be controlled by changing the geometry as well as thickness of the material, you can also apply coatings or form composite materials (eg constrained layer) but there are obviously limits to what can be done for a loudspeaker cone.
On the other hand if we chose a material which diplays high amounts of hysteresis to control the resonances, we now have bigger energy losses (ie another form of distortion).
I suppose it comes down to which is the greater evil, and trying to kill that while keeping in the back of your mind the effect of the other problem.
I don't design speaker cones, so I have not carried out these measurements to determine how significant these effects are on speaker cones.
Anyway, it is something to be aware of I suppose.
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Why should energy loss necessarily imply distortion? An ideal resistor will exhibit energy loss (it dissipates energy associated with the electrical current in the form of heat) but it doesn't create distortion. It just reduces the current generated by a given voltage. No harmonics or intermodulation products are generated. Are you defining a non-frequency-dependent and phase-shift-free reduction in the signal as distortion?
Or are you instead arguing that hysteresis directly causes distortion but it's not because it causes energy loss?
Few
Energy loss does not necessarily imply distortion. But most energy losses are usually non-linear.
Resistors (ie non-perfect resistors) are a good example, as you apply more power across them the resistance increases. The current is not directly proportional to voltage across the resistor because the resistance actually increases as it heats up.
So the energy loss is non-linear.
Hysteresis effects of materials can be much more non-linear than this.
For a perfectly elastic material you would see a perfectly straight line between load (ie force) and displacement.
However when you apply cyclic loads to materials this is not the case, there is hysteresis.
The best example would be to compare it with a mosfet. An ideal mosfet would have a straight line of Id vs Vgs. However this is not the case. On top of that the properties of Id vs Vgs also change with changes in temperature. So when you apply a sine wave through a mosfet you get a sine wave plus some distortion. That is, it is no longer a perfect sine wave.
It is the same or at least similar with hysteresis of materials.
Resistors (ie non-perfect resistors) are a good example, as you apply more power across them the resistance increases. The current is not directly proportional to voltage across the resistor because the resistance actually increases as it heats up.
So the energy loss is non-linear.
Hysteresis effects of materials can be much more non-linear than this.
For a perfectly elastic material you would see a perfectly straight line between load (ie force) and displacement.
However when you apply cyclic loads to materials this is not the case, there is hysteresis.
The best example would be to compare it with a mosfet. An ideal mosfet would have a straight line of Id vs Vgs. However this is not the case. On top of that the properties of Id vs Vgs also change with changes in temperature. So when you apply a sine wave through a mosfet you get a sine wave plus some distortion. That is, it is no longer a perfect sine wave.
It is the same or at least similar with hysteresis of materials.
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Thanks for the clarification of your intent. Your expanded explanation points (correctly, I think) to nonlinearity as the source of distortion rather than to energy dissipation as the source. With that in mind, would you accept "To keep it simple hysteresis is bad. Hysteresis means nonlinearity. This means distortion." as a rephrasing of your earlier statement?
I agree whole heartedly. The road is fantastic. But the true adventure is the road on the leeward side...
Threadjack - As a builder of original Ariels (the first published cabinet design with the odd angles at the start of the labyrinth, and sticky-dome -9000's !!)
I have to ask if anybody has surrounds on the woofers that are lightly discoloring to a brownish-mustard color, and are cracking on the extreme surface? Also, does anybody have a spare set of woofers they might part with??
Yes it is - what a wild and wonderful place. Stark, windswept beauty. We called it the "Sebring Highway" because of the all the tourists in their rented Sebring convertibles.
Right! We need to tell more people this. Keep them away from the leeward side between Ulupalakua and Hana. After the earthquake took out a couple of bridges, it was soooo peaceful back there. Like a locals only sanctuary.
Do you have any measurements? Did you do anything to optimize the path length differences over the drivers height?
Lynn, any updates on your design process, changes in your thinking?
Gary, thanks for your design contribution. Do you have any listening impressions or changes to report? Also, I was wondering if you have tried to incorporate your ribbons for high frequency extention above the Radian CD?
There surely are many like me who do not have the knowledge, or tools to perfect such a speaker. We are relying on your efforts to enhance our DIY high quality speaker options.
We are looking forward to any more progress from the two of you, or others inspired by this thread.
Thanks
NW
Gary, thanks for your design contribution. Do you have any listening impressions or changes to report? Also, I was wondering if you have tried to incorporate your ribbons for high frequency extention above the Radian CD?
There surely are many like me who do not have the knowledge, or tools to perfect such a speaker. We are relying on your efforts to enhance our DIY high quality speaker options.
We are looking forward to any more progress from the two of you, or others inspired by this thread.
Thanks
NW
Hi Norris,
I haven't checked in for quite awhile, but have been made quite a bit of progress on the new speakers, which now have a name: the Benaroyas, named after Benaroya hall, home of the Seattle Symphony. Benaroya is a fantastically musical-sounding hall. Strings sound opulent, and the winds and percussion have an appealing presence. By this time I have heard several of the world's great orchestras there, and I have even played on its stage under Gerard Schwartz (1st timpani in Mahler's Symphony No. 1).
Last time I wrote, I had only gotten far enough to hear a single speaker, but had made enough progress on the crossover that it was time to proceed with building up a stereo pair. I was down to the last couple of hours prior to completion before it was time to leave for RMAF '10. Lynn graciously hosted me for the weekend at his home not far from Denver. The timing for the event was excellent. It gave Lynn and me a chance to again compare our responses to things we were both hearing at the same time, which is an important calibration point for our conversations about things we hear separately.
Upon my return from Denver, I had the pleasure of conducting Beethoven's Fantasy in C minor for Piano, Chorus and Orchestra with the Bremerton Symphony and Chorale. Tania Rivers-Moore was the piano soloist. You can read the review at MusicWeb International if you're curious. If work on the speakers was to be further delayed, it might as well have been for a worthwhile endeavor!
I completed the crossovers (as shown in the previously-posted schematic), did some quick measurements, and started listening to real music -- at last! . First reaction: very promising. I felt that even if further tweaking didn't improve things, this project was already quite worthwhile. But the crossover between the TD15M and the Radian wasn't quite right. The mixed-order (2nd order LP/3rd order HP) wasn't summing correctly. Next I tried a 3rd order LP for the TD15M. Much better, but could still benefit from tweaking.
After more listening to more and more recordings, I noticed that I was finding musical satisfaction in a higher percentage than before of items in my music collection, which was a major goal of the whole project. I hate it when I look back and realize that my listening tastes are being skewed by the flaws in the equipment, since I am most likely to listen to the recordings that sound good in the system. To be honest, I would rather have a system that makes excellent performances sound musical and beautiful than one that makes audiophile recordings sound "spectacular." My definition of musical and beautiful is that I should be able to hear everything that is happening in the music (balances not obscured by glare or other artifacts), and that the tone colors of instruments and voices should be realistic, which to me sounds beautiful in real life. I have never heard a "hi-fi spectacular" system accomplish this.
My next step was to add the Aurum Cantus G3 ribbons. This of course led to experimentation with the upper crossover. So far I have tried various approaches with the HP filter on the ribbons, and run the Radian/Azurahorn both wide open on top and with a small inductor lopping off the highest frequencies. I haven't yet found a configuration that sounds right with all recordings, but it's already better than I have ever before experienced with horn speakers.
One thing I heard at RMAF left a big impression on me (and Lynn as well) -- the new 140-15D dipole ribbon tweeter by Aleksandar Radisavljevic of RAAL. We heard these tweeters extending the top end of a pair of Rethm speakers. The Rethms were operating wide open at the top, with just a HP filter on the RAALs, and the results were fabulous. Lynn ended up with a pair of these tweeters for himself, in addition to the new 9" Lazy Ribbon RAALs. I only have the Aurum Cantus tweeters, but experimented with both frontward and rearward facing. The results have left me really tempted to try the RAAL dipoles, but my wife is thinking I have already spent more than enough on this project. Maybe I can work something out here...we'll see.
I can't say that I have arrived at the final destination yet, but I'm definitely well on the way.
Gary Dahl
I haven't checked in for quite awhile, but have been made quite a bit of progress on the new speakers, which now have a name: the Benaroyas, named after Benaroya hall, home of the Seattle Symphony. Benaroya is a fantastically musical-sounding hall. Strings sound opulent, and the winds and percussion have an appealing presence. By this time I have heard several of the world's great orchestras there, and I have even played on its stage under Gerard Schwartz (1st timpani in Mahler's Symphony No. 1).
Last time I wrote, I had only gotten far enough to hear a single speaker, but had made enough progress on the crossover that it was time to proceed with building up a stereo pair. I was down to the last couple of hours prior to completion before it was time to leave for RMAF '10. Lynn graciously hosted me for the weekend at his home not far from Denver. The timing for the event was excellent. It gave Lynn and me a chance to again compare our responses to things we were both hearing at the same time, which is an important calibration point for our conversations about things we hear separately.
Upon my return from Denver, I had the pleasure of conducting Beethoven's Fantasy in C minor for Piano, Chorus and Orchestra with the Bremerton Symphony and Chorale. Tania Rivers-Moore was the piano soloist. You can read the review at MusicWeb International if you're curious. If work on the speakers was to be further delayed, it might as well have been for a worthwhile endeavor!
I completed the crossovers (as shown in the previously-posted schematic), did some quick measurements, and started listening to real music -- at last! . First reaction: very promising. I felt that even if further tweaking didn't improve things, this project was already quite worthwhile. But the crossover between the TD15M and the Radian wasn't quite right. The mixed-order (2nd order LP/3rd order HP) wasn't summing correctly. Next I tried a 3rd order LP for the TD15M. Much better, but could still benefit from tweaking.
After more listening to more and more recordings, I noticed that I was finding musical satisfaction in a higher percentage than before of items in my music collection, which was a major goal of the whole project. I hate it when I look back and realize that my listening tastes are being skewed by the flaws in the equipment, since I am most likely to listen to the recordings that sound good in the system. To be honest, I would rather have a system that makes excellent performances sound musical and beautiful than one that makes audiophile recordings sound "spectacular." My definition of musical and beautiful is that I should be able to hear everything that is happening in the music (balances not obscured by glare or other artifacts), and that the tone colors of instruments and voices should be realistic, which to me sounds beautiful in real life. I have never heard a "hi-fi spectacular" system accomplish this.
My next step was to add the Aurum Cantus G3 ribbons. This of course led to experimentation with the upper crossover. So far I have tried various approaches with the HP filter on the ribbons, and run the Radian/Azurahorn both wide open on top and with a small inductor lopping off the highest frequencies. I haven't yet found a configuration that sounds right with all recordings, but it's already better than I have ever before experienced with horn speakers.
One thing I heard at RMAF left a big impression on me (and Lynn as well) -- the new 140-15D dipole ribbon tweeter by Aleksandar Radisavljevic of RAAL. We heard these tweeters extending the top end of a pair of Rethm speakers. The Rethms were operating wide open at the top, with just a HP filter on the RAALs, and the results were fabulous. Lynn ended up with a pair of these tweeters for himself, in addition to the new 9" Lazy Ribbon RAALs. I only have the Aurum Cantus tweeters, but experimented with both frontward and rearward facing. The results have left me really tempted to try the RAAL dipoles, but my wife is thinking I have already spent more than enough on this project. Maybe I can work something out here...we'll see.
I can't say that I have arrived at the final destination yet, but I'm definitely well on the way.
Gary Dahl
