Tweeter comparaison

[Chromatischism]

Prob with 3/4" drivers is their wide dispersion, which makes less accentuated'crashing cymbals'.

Slap that puppy in a waveguide and control the directivity. Best of both worlds.

It's 2022! Tweeters and waveguides have evolved to become one.

 

[Chromatischism]

when you cross your 19 mm dome at 1.2 khz and then crank it to 110 DB if it doesn't blow up completely

First, I'm not aware of any 19 mm domes being crossed at 1.2 kHz. If you know of an example, please provide a link. Mine are at 1.8 kHz (crossed to a 6.5" paper cone) and 2.6 kHz (crossed to a 6.5" aluminum cone), in somewhat deep waveguides. The tweeter is the last thing to give up in the speaker.

Second, no sane person cranks their system to 110 dB during actual usage unless they are inviting hearing damage or are not even in the room. That might be good for showing off, but I think it's pretty reckless.

 

[JWAmerica]

Is there a good reason to go smaller than 25mm when you can get a Peerless corundum dome that can be crossed at 2Khz comfortably (1.2Khz at the lower end)?

 

[Chromatischism]

"safe" level for 8 HOURS A DAY is 85 db

This is actually not true. The hearing safety standards developed by OSHA (Occupational Safety and Health Administration) are designed such that the amount of hearing loss accumulated over a working lifetime is kept to a point where you can still hold a normal conversation where you can understand human speech towards the end of your life. The actual exposure thresholds to prevent hearing loss are much lower.

 

[Chromatischism]

Is there a good reason to go smaller than 25mm when you can get a Peerless corundum dome that can be crossed at 2Khz comfortably (1.2Khz at the lower end)?

Tweeter choice is always about the implementation with other drivers and the speaker enclosure itself. There are few wrong choices because it always depends what it's paired with. Like strawberry and banana, or chocolate and peanut butter.

From what I've seen, the reason to choose a smaller tweeter is the wider dispersion carried out to 20 kHz. It needs to be crossed to a bass driver higher though, so you must choose a capable one that won't start narrowing its directivity causing a drop in sound power in the mid band. This could mean using a smaller driver thus giving up some bass capability. It's also a good time for a three-way.

One way to solve this problem is to horn load the tweeter, which boosts the low end and lets you lower the crossover point and widen the bass driver's dispersion. Here you get the best of both worlds and can match the directivity of the drivers optimally, while using a bigger bass driver. Since speakers are always about trade-offs, the trade-off here would be the spacing between the drivers increasing which means it's not going to be coherent like a coaxial right up near the speaker.

If you don't care about wide dispersion beyond 10 kHz and won't be using a waveguide, or only a shallow one, it's better to use a larger tweeter.

 

[beagleman]

please explain how 3/4" cloth-soaked-in-asphalt dome driven by a VC half the size of a wedding ring can reproduce a crash of a 1 foot cymbal ...

it can't do that any more than a 6" woofer can reproduce the sound of artillery fire.

there is a condition among DIY speaker builders where they look at SPL of one driver relative to another and at SPL at one frequency relative to SPL at another frequency ....

THOSE THINGS DO NOT MATTER

it is the ABSOLUTE spl that matters - not SPL relative to anything else

the absolute max SPL of a 3/4" soft dome will be about 100 db PEAK @ listening position.

rock concerts are regulated to 100 db AVERAGE level @ listening position ...

peak to average ratio of music is about 10 - 20 decibels ...

3/4 domes are suitable only for nearfield monitors and even then only for the subcompact ones that you have to carry with you on a plane or something ...

if you don't care about SPL then just take a headphone capsule and run it as a full range speaker with some linkwitz transform to extend the bass response. you will get maybe 30 decibels or so - somewhere in the noise floor of your room - but what do you care ? since it will be a full range it will match its own sensitivity so no issues !

using a 3/4" dome tweeter ( with perfect sound quality ) is one of the biggest regrets in my speaker building life. even though it was my first speaker and i was in high school i will never forgive myself for this.

Not sure what it is about you. The lack of knowing what you are talking about, or how you are all over the place and feel you have to set everyone "Straight" with your knowledge, or the Rude and silly way you post, but till this point, I have liked literally everyone here, but feel the need to BLOCK/IGNORE you entirely.

My stomach is literally aching after reading all the nonsense you keep posting in this thread alone....Wow.
Wake up and realize how you come off............

 

[JWAmerica]

Tweeter choice is always about the implementation with other drivers and the speaker enclosure itself. There are few wrong choices because it always depends what it's paired with. Like strawberry and banana, or chocolate and peanut butter.

From what I've seen, the reason to choose a smaller tweeter is the wider dispersion carried out to 20 kHz. It needs to be crossed to a bass driver higher though, so you must choose a capable one that won't start narrowing its directivity causing a drop in sound power in the mid band. This could mean using a smaller driver thus giving up some bass capability. It's also a good time for a three-way.

One way to solve this problem is to horn load the tweeter, which boosts the low end and lets you lower the crossover point and widen the bass driver's dispersion. Here you get the best of both worlds and can match the directivity of the drivers optimally, while using a bigger bass driver. Since speakers are always about trade-offs, the trade-off here would be the spacing between the drivers increasing which means it's not going to be coherent like a coaxial right up near the speaker.

If you don't care about wide dispersion beyond 10 kHz and won't be using a waveguide, or only a shallow one, it's better to use a larger tweeter.

You're making a good case for the use of supertweeters crossed at 10-12kHz. Halfway decent 25mm domes have wide dispersion to at least 10kHz.

 

[fineMen]

You're making a good case for the use of supertweeters crossed at 10-12kHz. Halfway decent 25mm domes have wide dispersion to at least 10kHz.

In case You designed such a cross-over yourself, You might have seen the problem with the vertical nulls. Of course again, if the listener is forced to stay in between +/-5° or so, that might be accepted.

If not, what about something else addressing the drooping off-axis response? It is urban legend, that signal constituents above 10kHz contribute significant less to the musical presentation than anything else.

see > ISO226:2003, musical content regularly has 10..20dB lower level above 10kHz than on average, added 20dB of less sensitivity of the ear in that range gives an attenuation of about 30..40dB, and then masking attenuates it further ...

But still there is need for the 'air' it brings. The supersonic parts above 10kHz could be radiated into the room using a single super-tweeter (for stereo), which is not aimed at the listener(s), but directed so, that it maximises the comb filter with all reflections. Such would enhance the spectral content, while not bothering the audience with inconsistent cues--due to irregularly correlated interferrence in the x/o-region.

Strange, a super-tweeter used very much like a sub-woofer? But bear with me. If the tweeter is not aimed at the listener, and its directivity isn't well shaped, the super-high hiss would to some part pass the listener anyway, only to come back from the walls, irregular, de-correlated, ironically very often from the backwall, from behind the listener. Listener should, as owner of platinum ears easily detect, that the sidewalls are dead quiet regarding that frequency range. The single super-tweet solves that problem.

Test it--we are DIY here. Run a super-tweet x/o'ed at the frequencies You suggested with some music. Aim it at You, aim it somewhere else ... report.

Thank You