A short question. The goal is to be crossed at around 3-3.5kHz with about electrically 12dB/octave slope, acoustically 24dB/octave is preferable if possible.
Which tweeter is more advanced in technology?
A. 19 mm. woven soft dome with ferrofluid cooling
B. 25 mm. woven soft dome with air vent cooling
Which tweeter is more advanced in technology?
A. 19 mm. woven soft dome with ferrofluid cooling
B. 25 mm. woven soft dome with air vent cooling
ferrofluid was used for voice coils long after voice invention. So ferrofluid is somewhat "more advanced".
But it can cause all sorts of problems, mainly due to aging processes.
Ferrofluid is now sometimes just used to improve power capability and reduce qts of cheap tweeters.
And it's out of fashion for high quality drivers.
But it can cause all sorts of problems, mainly due to aging processes.
Ferrofluid is now sometimes just used to improve power capability and reduce qts of cheap tweeters.
And it's out of fashion for high quality drivers.
&
The answer is that as-described, neither is 'more advanced' or 'less advanced' than the other. Size, and the presence or lack of ferrofluid does not automatically make a drive unit 'advanced' or otherwise -same for whether it has a loading or decompression chamber or not.
That being said, assuming a fairly conventional 'modern' speaker, most quality 3/4in domes or 1in domes should have zero issue with power-handling crossing at 3KHz or above to a midbass, especially if you can hit LR4 slopes with a 2nd order electrical filter, although the polars / polar match is likely to be fairly rubbish at that frequency, the latter being less of an issue with a 3 way or > of course.
The Seas 22TAFG is a good example of a high tech modern tweeter. Its a 19mm alu/mg alloy dome and VC with a larger fabric surround, having the surface area close to a 27mm dome. You have the top end extension of a smaller metal dome coupled with the lower rolloff of a larger soft dome. This is a very natural sounding tweeter with lots of air and a smooth upper midrange.
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It also has the high HD2 of all tweeters which use the flexible surround as an active part of their radiating surface, and rapidly rising distortion of all orders < 2KHz.
Still a good tweeter though & depending what you do with it, it can be crossed lower than might be believed. I quite like it.
Still a good tweeter though & depending what you do with it, it can be crossed lower than might be believed. I quite like it.
The elevated 2nd order HD is the tradeoff with the 22TAFG, but being mostly 2nd order, it doesn't sound unpleasant if the crossover isn't pushed too far down. Despite the worse specs on paper, this tweeter delivers big time with really transparent sound while having warm sounding, non fatiguing upper mids. The fix to reducing H2 close to lower rolloff is to notch the primary resonance. That fixes most of the audible H2 above the electrical crossover HP and improves power handling as well.
The Peerless XT25 suffers from similar elevated HD as well, but it also has the reputation of sounding airy and extended thanks to the center of the diaphragm being fixed (ring radiator design) which can reduce the phase cancellation typically observed around 13k on most 1" HF domes.
The Peerless XT25 suffers from similar elevated HD as well, but it also has the reputation of sounding airy and extended thanks to the center of the diaphragm being fixed (ring radiator design) which can reduce the phase cancellation typically observed around 13k on most 1" HF domes.
Although many others describe the XT25 and it's Scan built versions as 'dark and well damped' due to its poor dispersion, unless the off-axis is properly accounted for, which shows how much value there is in subjective evaluations of tweeters (or any drive unit), especially when done in a system context. 
I can't honestly say I've ever found major broadband improvements in HD2 from damping the Fs primary resonance alone, although it certainly improves power handling & ensures the HP slope remains constant. You can get some HD improvements with most hard dome drivers with a bell mode up to about 30KHz from notching that, which can be useful. The main issue I've found with the H1283 is that it can sometimes get pushed lower than ideal -you can do it, as seen in the Canalis speakers, but best in lower power / limited SPL systems to keep that rising (especially higher order) distortion in check.
I can't honestly say I've ever found major broadband improvements in HD2 from damping the Fs primary resonance alone, although it certainly improves power handling & ensures the HP slope remains constant. You can get some HD improvements with most hard dome drivers with a bell mode up to about 30KHz from notching that, which can be useful. The main issue I've found with the H1283 is that it can sometimes get pushed lower than ideal -you can do it, as seen in the Canalis speakers, but best in lower power / limited SPL systems to keep that rising (especially higher order) distortion in check.
The XT25 sounds bright to me (on axis) compared to some of the other common 1" soft domes, though not nearly as bright as most metal domes. The ScanSpeak version sounds smoother and a bit more refined, probably due to the dome material.
The higher H2 throughout the 2k+ range gives the XT25 much of its snappy, forward midrange character, sort of subdued upper treble. Alot of the perceived tonal balance of a tweeter can be skewed by the distortion spectrum.
I run 19mm VC or smaller tweeters.with an Fs notch if its to be crossed under 3k 2nd order. Its almost always reduced even order HD for me and sort of sanitizes the mids. Interesting thing is, when adding a zobel, that is when the sound becomes dark. This is the case with most tweeters post crossover when a zobel is applied. It may be an issue with the padding series resistance allowing more voltage drop across the tweeter with help of VC inductance rise as opposed to the zobel's impedance linearizing effect reducing the voltage drop at the highest frequencies.
The higher H2 throughout the 2k+ range gives the XT25 much of its snappy, forward midrange character, sort of subdued upper treble. Alot of the perceived tonal balance of a tweeter can be skewed by the distortion spectrum.
I run 19mm VC or smaller tweeters.with an Fs notch if its to be crossed under 3k 2nd order. Its almost always reduced even order HD for me and sort of sanitizes the mids. Interesting thing is, when adding a zobel, that is when the sound becomes dark. This is the case with most tweeters post crossover when a zobel is applied. It may be an issue with the padding series resistance allowing more voltage drop across the tweeter with help of VC inductance rise as opposed to the zobel's impedance linearizing effect reducing the voltage drop at the highest frequencies.
If you want a more advanced treble unit, choose the one hand carved from Unobtainium and solid BS by virgins.
If the question is "Which one will sound better?" A 19mm treble with Ferrofluid can be designed to sound better than 25mm without.
Assumes loadsa stuff about skill of designer bla bla. Treble units without Ferrofluid demonstrate audible compression.
Present day Ferrofluids are MUCH better than when I first used them circa 1980 ... and should last 'indefinitely'.
If the question is "Which one will sound better?" A 19mm treble with Ferrofluid can be designed to sound better than 25mm without.
Assumes loadsa stuff about skill of designer bla bla. Treble units without Ferrofluid demonstrate audible compression.
Present day Ferrofluids are MUCH better than when I first used them circa 1980 ... and should last 'indefinitely'.
Interesting!
I have a pair of the 1980’s speakers: ADS L980 which are equipped with the ferrofluid-cooled tweeters—0.75” woven soft dome. They haven’t had been opened/rebuilt before since 1986.
If I didn’t misunderstand, replacing the old ferrofluid with a modern one could be done on them and would yield positive results, am I correct?