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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
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In Reply to: RE: I do agree that designers probably can make the best use of measures, but two questions. posted by AJinFLA on January 6, 2008 at 17:09:34:
Hi AJ
“And for an electro-mechanical/acoustic conversion is lossiness ideal to preserve signal integrity?â€
From an efficiency standpoint yes but also no as the more important thing is that the resistance which makes up the loss be constant with frequency.
“We've been through this before on DIYAudio :-). I don't design for "exotic appeal" any more than Linkwitz does. Your argument against hold no water in (competently designed) real world applications. The rigid cones are certainly much harder on XO & system design, but the benefit is lower overall distortion and greater transparency and clarity than soft lossy cones. Some find this microscope (accurate) viewing of their recordings offensive and would rather have some softening cream applied. Some don't.â€
I wasn’t aware you designed speakers, cool, by exotic appeal I mean things done for appearances alone. Some examples were the use of Kevlar, the “wet look†(not to be confused with damping goo), exotic baskets and so on.
I present no argument; I have measured the effect I mentioned on many occasions.
If one has two identical motor systems and suspensions, where the only difference was that one had a “hard†radiator which had larger breakup features, I would not expect the distortion or sound in the piston band to be different other than increases where the fundamental is, 1 / 2, 1 / 3, 1 / 4 etc the frequency where the peaks are.
Keep in mind a compression driver is a different ball of wax than a direct radiator too, fwiw, I used the DE-25 on several of the speakers at my old job, it is a very nice driver and very rugged to boot.
A basic problem with discrete horn systems, just like discrete direct radiators and even more so, is that at crossover the drivers are too far apart and so produce an interference pattern (regions of addition and cancellation dependant on angular position.)
If anyone in hifi ever did spherical measurements, they would see big fingers and nulls going every which way, the sound doesn’t just go where the horn is pointed.
We use Pat Brown’s (Synaudcon) company ETC to do these, the measurements are not something I can do here..
http://www.proavmagazine.com/industry-news.asp?sectionID=1765&articleID=595630
Stored energy is a popular topic but keep in mind that in a direct radiator, phase shift reflects the low frequency amplitude, I mean an electrical filter with the same amplitude, has the same phase shift. So, one might not wish to describe a vented box which has a 180 degree phase lag commensurate with a 2nd order roll off and Q of such and such (the energy storage), while one also has cone breakup and internal reflections which truly is stored energy.
Personally, I couldn’t even consider a first order filter, in band, one needs a 2 nd order slope just to reach “constant excursion†in the compression driver and more than that if your going to need lowest distortion and greatest output.
Its kind of funny how much different our horns look when you let the radiation pattern and measurements dictate the shape and configuration.
Best,
Tom
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Follow Ups
- RE: I do agree that designers probably can make the best use of measures, but two questions. - tomservo 01/6/0820:23:46 01/6/08 (0)
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