That has happened to me many times.
That is my goal. I just happened upon the wave form difference while trying some sims. I wil study the coding to assure i havent made an error and to refine the values.
In the sims i see the same effective pressure on positive and negative strokes, its just that the negative stroke partical mass shifts towards the center. I will refine and report back as something like this is interesting to me.
ron
Ron,
Agreed. However when I find myself at odds with the greybeards, I am always wrong. I would be very nervous if I found I was in conflict with mathematics/physics that is several hundred years old and still standing as being correct.
I worked with a guy a long time ago, very bright with a Phd and many years of experience. One time he got his nose so close to his calculations he was blinded by his own derivations. He proved that the sine of an angle could be greater than 1.0 and would argue the point because he needed it to make his equations match reality from a test result. I remember my grey headed boss tossing him out of his office based on that one sticking point.
One sided thinking is definitely the enemy of progress, but so is violating basic physics and math. Just because a computer program produces a number it is not necessarily 100% correct. If your computer methods cannot reproduce simple classic solutions I would be suspicious of the more complex results, that comes form somebody who has screwed up and been fooled many many times.
Agreed. However when I find myself at odds with the greybeards, I am always wrong. I would be very nervous if I found I was in conflict with mathematics/physics that is several hundred years old and still standing as being correct.
I worked with a guy a long time ago, very bright with a Phd and many years of experience. One time he got his nose so close to his calculations he was blinded by his own derivations. He proved that the sine of an angle could be greater than 1.0 and would argue the point because he needed it to make his equations match reality from a test result. I remember my grey headed boss tossing him out of his office based on that one sticking point.
One sided thinking is definitely the enemy of progress, but so is violating basic physics and math. Just because a computer program produces a number it is not necessarily 100% correct. If your computer methods cannot reproduce simple classic solutions I would be suspicious of the more complex results, that comes form somebody who has screwed up and been fooled many many times.
have been shocked by the cone control and concomitant bass SPL that these are capable of.
I have been thinking on this factor. The normal " hit or miss" designs in the past have very little( or generalized) acoustical physics application. I have even seen statements like " a CC volume between 3.5 to 5 liters". To me, as an engineer, this is like saying that any huge tolerence in any system is acceptable. The only reason for a tolerence in any design is to adapt to manfacturing and required performance potential. Its normal to say that a tighter tolerence cost more in the end product, but as you approach a tighter tolerence you achieve a closer to optitum performance potential. Its very simular to " blueprinting" an engine in which you take the engineers nominal requirements and re-define the tolerences to a tighter margine to achieve a greater performance.
In horn systems this means defining exact values and combining the target goals to achieve the maxium performance from the most simple design with the less(or none) wasted space.
One of the great falsehoods i have seen is an equal loading requirement from the front surface of the cone to the rear, the loading affects both surfaces regardless if its one one side or the other. Its nothing more than a piston with loading.
ron
ron
I have been thinking on this factor. The normal " hit or miss" designs in the past have very little( or generalized) acoustical physics application. I have even seen statements like " a CC volume between 3.5 to 5 liters". To me, as an engineer, this is like saying that any huge tolerence in any system is acceptable. The only reason for a tolerence in any design is to adapt to manfacturing and required performance potential. Its normal to say that a tighter tolerence cost more in the end product, but as you approach a tighter tolerence you achieve a closer to optitum performance potential. Its very simular to " blueprinting" an engine in which you take the engineers nominal requirements and re-define the tolerences to a tighter margine to achieve a greater performance.
In horn systems this means defining exact values and combining the target goals to achieve the maxium performance from the most simple design with the less(or none) wasted space.
One of the great falsehoods i have seen is an equal loading requirement from the front surface of the cone to the rear, the loading affects both surfaces regardless if its one one side or the other. Its nothing more than a piston with loading.
ron
ron
Ron,
There are obviously some tolerances that are extremely important in a design and are highly optimized. Then there are tolerances that are really not so critical, typically this is the majority. If you over tolerance a part you drive the cost out of sight for little gain. I worked with a some engineers that put tight tolerances on every feature of their part because they could not visualize what was important and ended up with something so expensive it was not competitive. But lets return to horns ...
I am not so sure. Remember that most of the hit or miss full range BLH designs are paired with low power tube amps. The output impedance of the tube amps is all over the map. So the effective Qts of the driver probably has a significant tolerance leading to a large variability in the required CC volume. The only way I see of tightening the tolerance on the CC is to design for SS amps. But that would be a non-purist approach and looked down on by the enlightened.
Only if you include a specific tube amp and only one driver in the optimization. If not then you need some adjustability in the enclosure design.
Ageed! There is a lot of bad information voodoo floating around with respect to full range drivers and horns that is being quoted as absolute truths.
One of the most entertaining threads I have read recently is over at the OB forum of the Audio Circles sight. A great discovery has been made by the single driver OB users. You can use a BSC circuit to rebalance the rising SPL response and it improves the system response dramatically. The life is not sucked out of the music and it really sounds better with the circuit! Every day I check the progress of this advance in the full range driver technology, sooner or later they will figure out it also helps the boxed speakers.
There are obviously some tolerances that are extremely important in a design and are highly optimized. Then there are tolerances that are really not so critical, typically this is the majority. If you over tolerance a part you drive the cost out of sight for little gain. I worked with a some engineers that put tight tolerances on every feature of their part because they could not visualize what was important and ended up with something so expensive it was not competitive. But lets return to horns ...
I am not so sure. Remember that most of the hit or miss full range BLH designs are paired with low power tube amps. The output impedance of the tube amps is all over the map. So the effective Qts of the driver probably has a significant tolerance leading to a large variability in the required CC volume. The only way I see of tightening the tolerance on the CC is to design for SS amps. But that would be a non-purist approach and looked down on by the enlightened.
Only if you include a specific tube amp and only one driver in the optimization. If not then you need some adjustability in the enclosure design.
Ageed! There is a lot of bad information voodoo floating around with respect to full range drivers and horns that is being quoted as absolute truths.
One of the most entertaining threads I have read recently is over at the OB forum of the Audio Circles sight. A great discovery has been made by the single driver OB users. You can use a BSC circuit to rebalance the rising SPL response and it improves the system response dramatically. The life is not sucked out of the music and it really sounds better with the circuit! Every day I check the progress of this advance in the full range driver technology, sooner or later they will figure out it also helps the boxed speakers.
So true. I have learned , the hard way, to establish tolerences toward what the final goal is. If you are trying to establish a " form fit and function" requirement then its different. I keep seeing ppl who ask will this different driver work in a design and i can only state, not to the optitum. I spent the majority of my life in aerospace, it was always better to be too tight than too loose.(CYA action). Lordy! most of my work would be blown up upon impact or detonation, so goes the hidden mistakes.
I try to design for the " middle of the road" approach. True its not optium, but its the only approach i can take for the masses. Most dont understand that the amp is part of the system, or the room volume or shape or even the source. To truly design for a given set of conditions would require several designs that i truly dont have time in my life for.( just discovered fly fishing for stream trout in NC with my lady, a hell of a lot more enjoyable than designing automated inspection systems for industry)
A great discovery LOL. Most do not consider the benefits of electronic compensation. They are hung up on some passive EQ system that they had in their dorm room. I primarly design around the horn/TL system due to the increased dynamic range and greater efficency, however most are not willing to invest of themselves into the greater design complexity.
ron
Well as far as amps go, i have everything from SET to Phase Linear ( you could weld with that one) and just about everything in between.
My current fav is battery powered Gainclones , but that is just a phase. One of my all time fav is some of the older Marantz 22xx( pre 1980) that i enjoyed rebuilding and slightly hopping up. Those amps gave a tube like sound with power to spare and one of my restored 2238 amps is driving my first horn design at my parents house. It still sounds good with the fostex Fe103 in a short horn with rapid expansion but Dad with his hearing loss ( God bless him) still complains that Benny Goodman just dosent have the punch that he heard live ( what ya expect?).
I am truly a fan of SS amps as they have the power and the inherent damping that even with HE horn systems make an obvious difference. Problem is most of todays SS amps are way overrated in watts and do not perform like the older equipment when power ratings were measured differently. Moms and Dads Marantz 2238 weighs about 40 lbs , with the original wood cover. It is only rated at 38 watts/channel. I have seen newer amps that were rated at 200 watts/channel that weighed around 10 lbs. I even tried explaining to a sales person that the advertised watt out put was more than the consumed power, after looking at the fuse rating and allowing for a 100% efficency conversion.
So much for new. There are still good newer amps out there , but you have to spend the $ to get IMHO what is considered acceptable performance.
ron
My current fav is battery powered Gainclones , but that is just a phase. One of my all time fav is some of the older Marantz 22xx( pre 1980) that i enjoyed rebuilding and slightly hopping up. Those amps gave a tube like sound with power to spare and one of my restored 2238 amps is driving my first horn design at my parents house. It still sounds good with the fostex Fe103 in a short horn with rapid expansion but Dad with his hearing loss ( God bless him) still complains that Benny Goodman just dosent have the punch that he heard live ( what ya expect?).
I am truly a fan of SS amps as they have the power and the inherent damping that even with HE horn systems make an obvious difference. Problem is most of todays SS amps are way overrated in watts and do not perform like the older equipment when power ratings were measured differently. Moms and Dads Marantz 2238 weighs about 40 lbs , with the original wood cover. It is only rated at 38 watts/channel. I have seen newer amps that were rated at 200 watts/channel that weighed around 10 lbs. I even tried explaining to a sales person that the advertised watt out put was more than the consumed power, after looking at the fuse rating and allowing for a 100% efficency conversion.
So much for new. There are still good newer amps out there , but you have to spend the $ to get IMHO what is considered acceptable performance.
ron
After 9 months I have just:
- finished off proper gravel filled deflectors
- put a bit of acoustic foam and felt inside the CC rather than old ceiling tile
- added a pair of phase plugs
- blutacked the speakers to some concrete slabs
Each one of these mods made a profound difference. Phase plugs especially seem to have opened up the treble in a very special way.
Yay!
Still no suprabaffles though - "I'm not having speakers with earlobes in our lounge" etc.
Steve
-------------
Gwen Nathan Photography
www.gwennathan.co.uk
- finished off proper gravel filled deflectors
- put a bit of acoustic foam and felt inside the CC rather than old ceiling tile
- added a pair of phase plugs
- blutacked the speakers to some concrete slabs
Each one of these mods made a profound difference. Phase plugs especially seem to have opened up the treble in a very special way.
Yay!
Still no suprabaffles though - "I'm not having speakers with earlobes in our lounge" etc.
Steve
-------------
Gwen Nathan Photography
www.gwennathan.co.uk
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