Guess I stir up a hornet nest, anyway Celef you are right almost all backcone emission is reflected and the small amount of fluff is used to tailor the response curve to satisfies the purist.
My take regarding cone weight is... lightest possible for best dynamic responses within the constain of physical laws. Why do you think every tweeter cone weight is 10mg to 150gm? Midrange 2 to 6gm and for woofer there is almost no way around reducing weight below 10g without compromising low frequency demands. Of course it also needs to rigid and possess the right characteristic like damping and curvature .
Pharos - Sorry I rather not discuss the merits of 1,2,3 ways speakers. I respect your view if you think which ever is best. In the end Hifi sound is believevity at its best for a lack of a better word, if what you have sound great to your ears then you found hifi nivarna.
Regarding Fletcher Munson curve - its basically a 3 dimension plot of our typical hearing sensitivities to loudness and frequency. Typical means 20 to 40 yr old with normal hearing on both ears. If you have a mild cold or if you are over 50's your response curve change dramatically. It is also for this reason to listen to many speakers on numerous time when selecting one.
Like I say If you listen to a speaker and like the way it sounds go for it. Enjoying music is your ultimate goal.
My take regarding cone weight is... lightest possible for best dynamic responses within the constain of physical laws. Why do you think every tweeter cone weight is 10mg to 150gm? Midrange 2 to 6gm and for woofer there is almost no way around reducing weight below 10g without compromising low frequency demands. Of course it also needs to rigid and possess the right characteristic like damping and curvature .
Pharos - Sorry I rather not discuss the merits of 1,2,3 ways speakers. I respect your view if you think which ever is best. In the end Hifi sound is believevity at its best for a lack of a better word, if what you have sound great to your ears then you found hifi nivarna.
Regarding Fletcher Munson curve - its basically a 3 dimension plot of our typical hearing sensitivities to loudness and frequency. Typical means 20 to 40 yr old with normal hearing on both ears. If you have a mild cold or if you are over 50's your response curve change dramatically. It is also for this reason to listen to many speakers on numerous time when selecting one.
Like I say If you listen to a speaker and like the way it sounds go for it. Enjoying music is your ultimate goal.
Our relative perception of secondary sources is not linear with level. Each room reflection, each diffraction has different properties attached with it, and they change over time. Unless we are careful and considered about all sound that enters the room, the perceived response can change with level, and parts of the reproduction can seem to drop out. Done right IMO, bass and treble remain intact at all levels.
Many thanks for the link, I'd guess a maze is a massive improvement on a tiny gap betwixt dome and magnet, plus there's MUCH more volume of air to compress, the two reasons why I use tiny " full range " cone drivers for tweeters. I wonder if the maze is much of an improvement over a spiral tapering tube; a company like KEF not only has to design good speakers, they also have to invent new stuff that they can give acronyms to and have fancy pics in adverts and brochures.
Heavy cone drivers do tend to have much lower sensitivity then drivers with lighter cones, i guess you can see this in small size subwoofers
Sure, but what happens to the 15” driver 101db/1w sensitivity if you double or tripple its moving mass?
Right, but with a 3200W amp it would still make 110dB at 20Hz
Here an example: Beyma 15LEX1600Nd https://www.beyma.com/speakers/Fich...-data-sheet-low-mid-frequency-15LEX1600Nd.pdf
Box 31.2L fu=80Hz Q=0.71 96dB/1W Amp=3200W
+24dB low shelf filter
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McCauley.com
: 6174 Specifications
not a small box, capable of 15Hz, 800 W, 129 dB max peak
(not sure what max SPL at 15 or 20 Hz is but this is a very serious pro sub woofer for sure!)
: 6174 Specifications
not a small box, capable of 15Hz, 800 W, 129 dB max peak
(not sure what max SPL at 15 or 20 Hz is but this is a very serious pro sub woofer for sure!)
I guess this is a very cool driver. But I doubt that it would do 123 dB @ 15 Hz. There are also some errors and ambiguities in this datasheet. Like an efficiency of 0.006 % which I think shpould read either 0.0066 or 0.66 %. But either of tjhese doesn't match with a sensitivity of 94 dB. They also list the peak-to-peak Vd. Although even half of it is quite nice admittedly. The TSPs would indeed give a nice low reflex tuning for Studio monitors and serious hi-fi but not one that is capable of 123 dB @ 15 Hz.
Regards
Charles
Regards
Charles
Not a chance.
110dB@20Hz requires a 38.8mm one-way Xmax.
Similarly, the McCauley subwoofer linked above would also have excursion troubles.
Chris
Well, that would be within its limits. But two of them in closed-box and appropriate EQing would probably be nicer. Even nicer would be to have it times two …..
Sorry for OT
Regards
Charles
Edit: Chris was faster and therefore things got mixed-up. I am refering to the Mc Cauley in a appropriate reflex box.
Sorry for OT
Regards
Charles
Edit: Chris was faster and therefore things got mixed-up. I am refering to the Mc Cauley in a appropriate reflex box.
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What about using 16 drivers, 16 x 4 inch long throw subs in a 30L box, or perhaps 32 at a squeeze. May not go incredibly loud but small stiff drivers might have a higher sensitivity than one cone that has to be much thicker to be stiff enough over 15 inches. Hart audio used lots of small bass drivers to augment a Tannoy concentric driver, they did a version with octagonal fronts that look well cool.
Capable bass
I run 8x15 inch drivers, per side, for deep bass. I ran the numbers, and this is what I came up with. Having accomplished this project, I will say there is very little music programme that taps the demand for this.
Oh my, the elusive 20Hz. But, for the majority of music, the bass lines are so distortion free, when I go back to listening to typical audiophile systems I can easily hear the gross bass distortion.
I was even more surprised when I ran the numbers for what i could get out of 2.8 cubic feet. 70hz, at 5% efficiency.
As we descend down in frequency from there, the required box size to maintain this same 5% efficiency grows quickly.
Hoffman's Iron Law lives in infamy.
We have now fully de-railed off topic. Let me tie this in by saying I use either ppsl bass, or reaction-cancelling plenum mounting methods. This takes the BOX out of the result.
As we ascend UP in frequency, it comes a point where a conventional box isn't so necessary either. But PLEASE do the math. 200Hz is still a 5.65 foot wavelength, where as 700Hz is only 19.37 inches
I run 8x15 inch drivers, per side, for deep bass. I ran the numbers, and this is what I came up with. Having accomplished this project, I will say there is very little music programme that taps the demand for this.
Oh my, the elusive 20Hz. But, for the majority of music, the bass lines are so distortion free, when I go back to listening to typical audiophile systems I can easily hear the gross bass distortion.
I was even more surprised when I ran the numbers for what i could get out of 2.8 cubic feet. 70hz, at 5% efficiency.
As we descend down in frequency from there, the required box size to maintain this same 5% efficiency grows quickly.
Hoffman's Iron Law lives in infamy.
We have now fully de-railed off topic. Let me tie this in by saying I use either ppsl bass, or reaction-cancelling plenum mounting methods. This takes the BOX out of the result.
As we ascend UP in frequency, it comes a point where a conventional box isn't so necessary either. But PLEASE do the math. 200Hz is still a 5.65 foot wavelength, where as 700Hz is only 19.37 inches
I used to think that too.
Until I built some large transmission lines with 12" woofers.
During the testing phase they were in 18mm MDF enclosures with one side screwed so I could open it and adjust the stuffing with screws roughly every 20cm.
Even at moderate levels the MDF between screws deformed enough to pinch the skin of my fingers.
I did not expect that especially since being TLs they were open at one end.
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