Hello,
We often talk here and elswhere about the properties of metal domes, and for the classic round shape, most of the time the discussion comes about the break up position and the internal damping of the said material (Be, Aluminum, Magnesium, ceramic, allows of those, etc)
I would like to focus on the often seen aluminium and magnesium allows as few are making 100% Magnesium dome tweeters (Fostex, Audax, ?)
So Magnesium is circa 1/3 harder at iso weigth than aluminum, i.e. 1/3 ligther at iso hardness.
Most of the time, I bet diferences are more due to the spl magnitude of those tweeters, the break up area relative to the materials we listen to, especially if non oversampling source and materials (16/44 with NOS digital source).
What about the internal damping many claim to be the force of the best materials like the Beyrilium and for the topic of the discussion : the magnesium ?
Aluminum is said to have good internal damping if I am not wrong at iso density vs some other metals used in tweeters like the Titanium or ceramic for instance, and our talked magnesium. I.e. aluminium is "softer" at iso mass which is not so bad but the early break-up - often circa 25k hz- !
Looking at the datasheets of some dome tweeters having pure magnesium or allows mixed with alumen, I am wondering "WTF" about those mixes ?! Indeed, most of the time the Mms is not ligther when Magnesium is entering in the comp of the tweeter domes : we often have the same weigth in the datasheets : 0.3 g to 0.4 g. the 0.4 g being sometimes the one with said ligth allow with the said Mg (or Be...).
Is that pure marketing ? Or does the Magnesium adds "something" ? More hardness at iso weigth (which is maining also maybe more early break-ups ?)
Also as Magnesium is harder, doees it mean less damping, i.e. more harsh sound ? All these things are not so clear to me !
I have the temptation to say that the most importat thing is the spl magnitude shape arriving at listening position. But voilà, micro details or details at low spl level are involved in the discussions soon ?! And because of that I am tempted to focus on hard dome tweeter VS soft domes, as the decay of notes in acoustic intruments is importat for me! Ah, so I imagine we talk about both of waterfall decay and ... what ? hard domes ... hardness = micro details? Is it clear for you ????
Not saying in the passive crossovers I experienced tons of way to make sound a hard dome different with the caps receips that color the sound more or less but anyway adds (it is a default, of course) to the sound ! I can make the Stan Getz saxo wood anch sounding like I want just playing with caps, for instance !
Is there some better voodoo you heard with Magnesium vs Aluminum ? Should I mortgage for Be by snobism or what ? Forget it and buy a good informativ soft dome tweeter à l like the 3004/66000 ?
Throw it all and focus on the magnitude off axis shape in the listening room by hundred mic measurements and sims with a tweeter you already have on hands? Or definitly focus first on the dome material choice then make your life after on the dev side of the filter ?
We often talk here and elswhere about the properties of metal domes, and for the classic round shape, most of the time the discussion comes about the break up position and the internal damping of the said material (Be, Aluminum, Magnesium, ceramic, allows of those, etc)
I would like to focus on the often seen aluminium and magnesium allows as few are making 100% Magnesium dome tweeters (Fostex, Audax, ?)
So Magnesium is circa 1/3 harder at iso weigth than aluminum, i.e. 1/3 ligther at iso hardness.
Most of the time, I bet diferences are more due to the spl magnitude of those tweeters, the break up area relative to the materials we listen to, especially if non oversampling source and materials (16/44 with NOS digital source).
What about the internal damping many claim to be the force of the best materials like the Beyrilium and for the topic of the discussion : the magnesium ?
Aluminum is said to have good internal damping if I am not wrong at iso density vs some other metals used in tweeters like the Titanium or ceramic for instance, and our talked magnesium. I.e. aluminium is "softer" at iso mass which is not so bad but the early break-up - often circa 25k hz- !
Looking at the datasheets of some dome tweeters having pure magnesium or allows mixed with alumen, I am wondering "WTF" about those mixes ?! Indeed, most of the time the Mms is not ligther when Magnesium is entering in the comp of the tweeter domes : we often have the same weigth in the datasheets : 0.3 g to 0.4 g. the 0.4 g being sometimes the one with said ligth allow with the said Mg (or Be...).
Is that pure marketing ? Or does the Magnesium adds "something" ? More hardness at iso weigth (which is maining also maybe more early break-ups ?)
Also as Magnesium is harder, doees it mean less damping, i.e. more harsh sound ? All these things are not so clear to me !
I have the temptation to say that the most importat thing is the spl magnitude shape arriving at listening position. But voilà, micro details or details at low spl level are involved in the discussions soon ?! And because of that I am tempted to focus on hard dome tweeter VS soft domes, as the decay of notes in acoustic intruments is importat for me! Ah, so I imagine we talk about both of waterfall decay and ... what ? hard domes ... hardness = micro details? Is it clear for you ????
Not saying in the passive crossovers I experienced tons of way to make sound a hard dome different with the caps receips that color the sound more or less but anyway adds (it is a default, of course) to the sound ! I can make the Stan Getz saxo wood anch sounding like I want just playing with caps, for instance !
Is there some better voodoo you heard with Magnesium vs Aluminum ? Should I mortgage for Be by snobism or what ? Forget it and buy a good informativ soft dome tweeter à l like the 3004/66000 ?
Throw it all and focus on the magnitude off axis shape in the listening room by hundred mic measurements and sims with a tweeter you already have on hands? Or definitly focus first on the dome material choice then make your life after on the dev side of the filter ?
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Interesting thing I did with some friends was eq with fir filters a cheap dayton alu dome vs blesima 34b I can do good measurements on my property I have a 35ft car park area that has no walls so I measure without reflections dicking my measurement I matched the tweeters eq and phase perfectly I used about 65k filters bc delay didn't matter with fir then crossed them over to a 8 inch at 1k hz 200db/Oct xo until the dayton ran out of excursion they sounded exactly the same in room. Obviously this is n=8 but between us we all agreed they sounded the same the di was the same but it really came down to the excursion. I like hard domes 🙃 imo our ears are stupid our brain hears what it wants room reflections are your real enemy.
Interresting testimonial. remind me a Jon Bocani 's member thread about tweeters and EQ.
Ok, so hard domes with high dropping spl off axis when looking the datasheets as a primary factor of choice ? The idea being is what you hear is the tweeter off axis as the loudspeakers on axis stands often between 15° to 30° max related to the listening position ?
I often read some people here saying the ideal tweeter should be up to 20 k hz as straigth till 45° as its on axis spl magnitude in order to be detailled yet. WHatever the voicing you do in the crossover by making it, for illustration, a little diving at listening position : but as a property of the filter choice and not the natural off axis seen on an IEC baffle. Hartmann curve for instance with its - 5 dB at 20 k fro the bass area, heard aat listening position.
Does it mean then, whatever the material of the tweeter, we should focus on the non beaming tweeter, i.e. the one that is as straigth spl at 45° as on axis ?
At the opposit some like to praise beaming tweeter by both choosing a large section - >= 29 mm - and front baffle/WG mariage giving spl loss off axis (aka beaming property) ?
I imagine this one is more forgiving with the room -less treflection arriving at deleted time to the ears- . Is there a consensus in a basic living room and heigth ceilling then at looking the off axis seen on IEC baffle in the datasheets ? With hard domes should I focus on the break up at say 15° to 30° off axis related to the triangle made by the loudspeakers base off set and the sweet spot ?
Ok, so hard domes with high dropping spl off axis when looking the datasheets as a primary factor of choice ? The idea being is what you hear is the tweeter off axis as the loudspeakers on axis stands often between 15° to 30° max related to the listening position ?
I often read some people here saying the ideal tweeter should be up to 20 k hz as straigth till 45° as its on axis spl magnitude in order to be detailled yet. WHatever the voicing you do in the crossover by making it, for illustration, a little diving at listening position : but as a property of the filter choice and not the natural off axis seen on an IEC baffle. Hartmann curve for instance with its - 5 dB at 20 k fro the bass area, heard aat listening position.
Does it mean then, whatever the material of the tweeter, we should focus on the non beaming tweeter, i.e. the one that is as straigth spl at 45° as on axis ?
At the opposit some like to praise beaming tweeter by both choosing a large section - >= 29 mm - and front baffle/WG mariage giving spl loss off axis (aka beaming property) ?
I imagine this one is more forgiving with the room -less treflection arriving at deleted time to the ears- . Is there a consensus in a basic living room and heigth ceilling then at looking the off axis seen on IEC baffle in the datasheets ? With hard domes should I focus on the break up at say 15° to 30° off axis related to the triangle made by the loudspeakers base off set and the sweet spot ?
Ohh both were in augerpro wave guides both 8 inch both elliptical of 8 inch so offaxis was controlled
Unfortunately, things are complicated. Simple parameters of the raw dome material don't tell you enough about how the tweeter is going to behave. The exact shape, material composition, coatings, treatments, geometry of pole piece/absorption, suspension, frequency, etc. all come into play. Soft dome tweeters are quite weak when poked at or thought of in typical mechanical ways, but do quite well at the frequencies involved.
In a badly designed speaker vs. well designed speaker, frequency response may be a major differentiator. And to a casual listener this is probably going to be the primary difference. Whether you like them or not, Bose does a good job of squeezing an acceptable amount of the right kind of sound out of cheap drivers to make the typical listener happy.
Between two well designed higher end units, I think frequency response differences are less likely to be the differentiator. Transient abilities, distortion profiles, and energy storage may make a difference to a critical listener . . . or at least make them part with their money.
There's also a philosophical aspect to all this: some people are opposed to highly resonant systems. They just don't like big breakup spikes in frequency response. Those people are typically not going to pursue a metal dome/cone. Other people want a high stiffness, pistonic cone/dome and gladly take the breakup regions in exchange for it.
A new alloy may just be a way to differentiate a new model or it might yield a performance benefit. It's hard to generalize. It's easy to imagine exotic materials as a justification for a higher price or new model, but it's also a diminishing returns game at the high end of pretty much any market. Does a McLaren's raw performance justify 4 times the price of a Corvette? Doesn't seem to matter to their target market. And how many of those McLarens are ever even driven hard (or much at all)?
Similar preference issue with directivity. Some people want an omnidirectional speaker, others want a well-controlled 45° cone of sound (or whatever number turns their crank), still others want a dipole.
A few interesting links:
https://www.stereophile.com/news/112204bw/index.html
"B&W . . . New 800 Series . . . . Most notable is the incorporation of a diamond diaphragm for the tweeter of the top units in the line, in place of the aluminum dome used in the past. This material was employed after Finite Element Analysis (FEA) indicated that the physical properties of other exotic materials, such as titanium and beryllium, did not offer significant advantages for audio performance despite being, variously, stiffer and/or less dense than aluminum. The production of the polycrystalline diamond diaphragms via a vacuum deposition procedure is expensive, and that is reflected in the retail pricing for these models. That said, I found it striking that the development engineers extolled, at length, the audible performance rather than the measurements."
Energy storage/tweeter tests down the page a bit
https://www.linkwitzlab.com/mid_dist.htm
"The measurements confirmed my preference, based on extensive listening, for the D2905/9700 as the more accurate tweeter than the SS metal dome. For any new design I would seriously consider the Seas T25CF002-06 tweeter, though I am not sure how directly the small improvements in measurement data translate into audible benefits."
http://www.zaphaudio.com/tweetermishmash/
In a badly designed speaker vs. well designed speaker, frequency response may be a major differentiator. And to a casual listener this is probably going to be the primary difference. Whether you like them or not, Bose does a good job of squeezing an acceptable amount of the right kind of sound out of cheap drivers to make the typical listener happy.
Between two well designed higher end units, I think frequency response differences are less likely to be the differentiator. Transient abilities, distortion profiles, and energy storage may make a difference to a critical listener . . . or at least make them part with their money.
There's also a philosophical aspect to all this: some people are opposed to highly resonant systems. They just don't like big breakup spikes in frequency response. Those people are typically not going to pursue a metal dome/cone. Other people want a high stiffness, pistonic cone/dome and gladly take the breakup regions in exchange for it.
A new alloy may just be a way to differentiate a new model or it might yield a performance benefit. It's hard to generalize. It's easy to imagine exotic materials as a justification for a higher price or new model, but it's also a diminishing returns game at the high end of pretty much any market. Does a McLaren's raw performance justify 4 times the price of a Corvette? Doesn't seem to matter to their target market. And how many of those McLarens are ever even driven hard (or much at all)?
Similar preference issue with directivity. Some people want an omnidirectional speaker, others want a well-controlled 45° cone of sound (or whatever number turns their crank), still others want a dipole.
A few interesting links:
https://www.stereophile.com/news/112204bw/index.html
"B&W . . . New 800 Series . . . . Most notable is the incorporation of a diamond diaphragm for the tweeter of the top units in the line, in place of the aluminum dome used in the past. This material was employed after Finite Element Analysis (FEA) indicated that the physical properties of other exotic materials, such as titanium and beryllium, did not offer significant advantages for audio performance despite being, variously, stiffer and/or less dense than aluminum. The production of the polycrystalline diamond diaphragms via a vacuum deposition procedure is expensive, and that is reflected in the retail pricing for these models. That said, I found it striking that the development engineers extolled, at length, the audible performance rather than the measurements."
Energy storage/tweeter tests down the page a bit
https://www.linkwitzlab.com/mid_dist.htm
"The measurements confirmed my preference, based on extensive listening, for the D2905/9700 as the more accurate tweeter than the SS metal dome. For any new design I would seriously consider the Seas T25CF002-06 tweeter, though I am not sure how directly the small improvements in measurement data translate into audible benefits."
http://www.zaphaudio.com/tweetermishmash/
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Today, with strong neodymium powered 'motors', it is probably not the diaphragm mass that matters
but more the rigidity & damping of the diaphragm that counts most.
Electrical vs mechanical damping is probably a topic of its own.
Dome tweeter materials has been going-on for so long now, but still interesting.
Have a look at this late 70's picture - I love it.
but more the rigidity & damping of the diaphragm that counts most.
Electrical vs mechanical damping is probably a topic of its own.
Dome tweeter materials has been going-on for so long now, but still interesting.
Have a look at this late 70's picture - I love it.
Wonder if a wave guide for a tweeter in a passive filter does supress the advantage of the fine detaiks given by a hard dome ? Due to the extra passive filter parts to lift the post 5k to 10k pitfall ?
SB26 cdc in augerpro 5" WG is planned but also the smoother fabric Morel CAT378 which needs perhaps less parts in the filter.
SB26 cdc in augerpro 5" WG is planned but also the smoother fabric Morel CAT378 which needs perhaps less parts in the filter.
What effect is it?
I think back to the time when I thought second order filters were more damaging than first order. I learned that with a higher number of components it's easier to make a second order mistake.. and first order mistakes are much less offensive (perhaps even less resonant).
I think back to the time when I thought second order filters were more damaging than first order. I learned that with a higher number of components it's easier to make a second order mistake.. and first order mistakes are much less offensive (perhaps even less resonant).
When a second order filter is correctly built, you won't have any 'resonant peak'. There is also another benefit
of second order (without resistor attenuation) and that is the parallel inductor across the tweeter provides
natural electrical damping. This situation doesn't happen with a simple series capacitor - first order.
So, the best situation is to have a tweeter of exactly matching output level of the mid. or woofer,
using a second order filter. I have always found second order filters to be quite 'musical'.
Also, as we know, you also have less lower frequencies stressing the tweeter.
of second order (without resistor attenuation) and that is the parallel inductor across the tweeter provides
natural electrical damping. This situation doesn't happen with a simple series capacitor - first order.
So, the best situation is to have a tweeter of exactly matching output level of the mid. or woofer,
using a second order filter. I have always found second order filters to be quite 'musical'.
Also, as we know, you also have less lower frequencies stressing the tweeter.
A flat frequency response will also mean perfect impulses and no resonances: frequency and time are mathematically related.
I believe (have to do measurements) I need a >=90 dB tweeter <=91 dB (2.8V). I found also some resistors to be intrusive in serie - can be good or a pain according what they add beyond their needed resitance. But that's a detail vis à vis of the rigth electrical values of the filter. Let's say last details of voicing when all is rigth already. Can eat some details with the basic ceramic resistors as well, which sometimes can be good I found when the trebles are too much detailled vis à vis of the mid.
You talk about electrical, but what about acoustical in the end ? I understand it as you cut off always highs (> 3 k hz ?) to be in a linear area of the tweeter to have your electrical order equal to the acoustica lorder. Rigth ?
I would like to staying second order on the tweeter side, at least avoiding forth electrical order because of the more cap. I do not mind yet at the end of the acoustical order cause I think I never tired, so heard yet, the difference between a second order (say acoustical for the discuss) and a fourth order. But sure if the tweeter I choose is strong enough, I try it according what are saying the sims and off axis measurements at sweet spot.
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hi,
i assume it makes sense if it is flat off axis at listening position ? (and for even better when flat at several off axis degrees, aka constant directivity ?)
If it's rolling off 2nd order within the transition band, then you have 6th order. Not that there's anything wrong with that, if used well, same as anything else. Everything's a compromise in design terms, we just select according to specific objectives we have for a given set of design requirements based on the best data available. Assuming we avoid the voodoo magic, obviously. 😉
I am in to try to avoid the vaudou magic.
I wonder if a non trained eyes can see the order roll off on a simple Fourrier transform ? It is not that easy as the low end diving of a tweeter and rhe start of the falling is never an evidence.
Is there filter dev soft like Vitruix that gives it in words ?
I surmise it is important for the timing offset at crossover point or Z axis recess if made passive according the final acoustical slope?
I wonder if a non trained eyes can see the order roll off on a simple Fourrier transform ? It is not that easy as the low end diving of a tweeter and rhe start of the falling is never an evidence.
Is there filter dev soft like Vitruix that gives it in words ?
I surmise it is important for the timing offset at crossover point or Z axis recess if made passive according the final acoustical slope?
Why is it not evidence? 
If you have an accurate on-baffle frequency response showing an inherent 2nd order acoustical rolloff, I can't think of many things that could be called better evidence of a 2nd order acoustical rolloff. 😉 The precise details of the eventual rolloff shape and frequency are up to the designer of course, and you have to account for frequency-varying impedance etc., but working with / accounting for that is just part & parcel of filter design.
Yes, usually we select or manipulate the electrical & acoustical orders to help account for driver offsets -some degree of acoustical & / or electrical asymmetry is more common than otherwise.
If you have an accurate on-baffle frequency response showing an inherent 2nd order acoustical rolloff, I can't think of many things that could be called better evidence of a 2nd order acoustical rolloff. 😉 The precise details of the eventual rolloff shape and frequency are up to the designer of course, and you have to account for frequency-varying impedance etc., but working with / accounting for that is just part & parcel of filter design.Yes, usually we select or manipulate the electrical & acoustical orders to help account for driver offsets -some degree of acoustical & / or electrical asymmetry is more common than otherwise.
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