Tweeter with MMS 0.3g and low FS

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El Wizardo

El Wizardo

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Joined 2013
#1
As title suggests, and non of loudspeaker databases cover tweeters...

Im looking for tweeters that have membrane weight (MMS) of 0.3g, low FS <400hz, and it should be cheap ?

Anyone have some recommendations or some actual database i can look this up ?
 
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#3
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#4
Be careful what you wish for: a low fs means the tweeter is open to large excursions below the crossover frequency.

Remember that a 12dB/octave rolloff is needed just to beak even, excursion-wise. That's why a first-order crossover is usually to be avoided (excursion increases at 6dB/octave below crossover).

This behaviour is true for signals above resonance. Below resonance, excursion diminishes, because a further 12dB/octave rolloff applies.

Because of the above, a high fs (if well damped) is actually preferable, as long as it's well damped (and well below crossover frequency).
 
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#5
I should have explained why im looking for these specific drivers.

I have an idea of a array (more like honeycomb) pattern with multiple tweeters, so that their distortion and excursion is divided amongs them ( think like at least 6 tweeters per channel) idea is for tweeters to cover midrange ~300-400hz

Something like this https://tektondesign.com/product/full-range-speakers/full-towers/2-10-perfect-set/#color

Someone here dissembled XO from one of these, and its interesting how they aproached it, and honestly, i like the way its heading.

I have found something interesting https://www.visaton.de/en/products/drivers/dome-tweeters/sc-10-n-8-ohm

MMS of just 0.1g !! but fs is 1,7khz so in reality it would be only good to cut them at 500hz or higher (in honeycomb config) and is really cheap, like 20-30e per driver.

I actually have a speaker with array of 6x Visaton FRS 5 x https://www.visaton.de/en/products/drivers/fullrange-systems/frs-5-x-8-ohm

They are full range cone speakers with nipple, but selling point here is MMS of just 0.5g, and i must say they sound way better than they should (considering their price) They are cut at 800hz 3rd order (i think)
 
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#6
Looks like a great idea, but, you're right, you'll need to find the right driver (and you'll probably need a lot more than 6!).

Excursion is going to be a major factor - most tweeters are down in the 1mm Xmax levels (if specified). Total diaphragm area and Xmax - as well as fs - will be the major factors in operating down to 400Hz.
 
#7
El Wizardo said:
MMS of just 0.1g
Click to expand...
sb 14 has a mms= 0.11g

https://sbacoustics.com/product/sb14st-c000-4/

It also does not need a baffle since it is too small to cause diffraction problems. Just needs a shelf filter to bring down 10khz. Maybe have a baffle-less array?

Still, the fs is not where you want it with your desired XO.

Good luck with the hunt.

edit.. fs=436 ..https://www.parts-express.com/Peerless-XT25TG30-04-1-Dual-Ring-Radiator-Tweeter-264-1016
 
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#8
keithj01 said:
Looks like a great idea, but, you're right, you'll need to find the right driver (and you'll probably need a lot more than 6!).

Excursion is going to be a major factor - most tweeters are down in the 1mm Xmax levels (if specified). Total diaphragm area and Xmax - as well as fs - will be the major factors in operating down to 400Hz.
Click to expand...
I would say 0.1mm should be highest allowed Xmax of tweeter anyway.

Tho one more important factor is price, sure i found the perfect drivers for these applications, but they cost like 200-300e each 😀 i need something down to like 20-50e max

Still, the fs is not where you want it with your desired XO.
Click to expand...
Well, thing is, with enough drivers connected we can achieve lower mid range frequencies, even below fs, but thats on paper, how its going to sound in reallty its a whole different beast we have to tackle, and that can be only done with trial and error 🙁

My current idea of a speaker system would as following

1-2 bass driver (at least 12" or 15" preferably) covers upto 100hz
2-4 mid range/ fullrange driver (around 4-6") covers 100-300hz(or where we decide to XO tweeters)
6+ tweeters to cover XO cut range and above
 
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#11
@stv, no problem it happens 🙂 Good thing its recommended ! 🙂

@keithj01 weight of driver moving parts will impact its distortion and music reproduction at given frequencies. Think about it, how much does a violin string weight ? And they are well capable of 300-400hz reproduction. In contrast, for bass you want that heavy membrane, more pressure, once again, an explosion that will cause a low frequency shockwave, that thing pushes insane amount of pressure.
 
#12
El Wizardo said:
weight of driver moving parts will impact its distortion
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Moving mass does not directly impact non-linear distortion. It does however affect efficiency and bandwidth. Having a limited bandwidth is a form of linear distortion, which is captured in the frequency response and can be compensated for in the crossover or equalizer.
 
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#13
TBTL said:
Moving mass does not directly impact non-linear distortion. It does however affect efficiency and bandwidth.
Click to expand...
Harmonics and resonance are a whole another topic tho, in my honest esoteric opinion, any vibration can induce resonance in anything (because everything is vibration), its fun topic to have while drinking and listening to music, but since science failed us in this department, without any meaningful progress in past 10k years, and anyone who wanted to research this was labeled pseudo scientist, a heretic etc.. we have no solid foundation on this, its just speculation at this point.

ANYWAY, back to the topic 😀 Its about efficiency, and how precise membrane can be controlled. A 15" driver can produce high tones, but they are going to be awful, membrane is too heavy to be controlled at such high speeds of higher frequency spectrum, thus, it will start doing its own thing, which is not what we want 🙂 So to over come this, we split the load to multiple drivers, thus increasing its efficiency. Point to be noted tho there is still "hard cap" on this, no amount of 15" drivers stacked will be able to produce clean higher frequencies, due to their construction and physical properties. Will sound better than a single 15", thats for sure.

Best we have at this point are low MMS drivers, trial and error, and just see if it works.
 
#14
TBTL said:
Moving mass does not directly impact non-linear distortion. It does however affect efficiency and bandwidth. Having a limited bandwidth is a form of linear distortion, which is captured in the frequency response and can be compensated for in the crossover or equalizer.
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Exactly - and those parameters are usually specified, so Mms is a property which is irrelevant to the user.
 
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#16
Btw, im not saying MMS is the ONLY factor at play here, everything is, i just believe its something that will impact efficiency of tweeters at such low frequencies the most.

Tho im curious, what happens when driver start playing below its Fs ? It becomes super inefficient ?
 
#17
as far as i know:
below fs efficiency will get very low and excursion very high.
also single suspension drivers (domes) will become very unstable, will not move piston-like anymore, may be damaged and distorsion will get very high.
double suspension drivers (cones, usually having a spider AND a surround, restricting motion to one direction only) will be more stable and can usually be driven harder below fs.
 
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#18
El Wizardo said:
Btw, im not saying MMS is the ONLY factor at play here, everything is, i just believe its something that will impact efficiency of tweeters at such low frequencies the most.

Tho im curious, what happens when driver start playing below its Fs ? It becomes super inefficient ?
Click to expand...
You can operate below fs, but it will need EQ (look up Linkwitz Transform). It is indeed very inefficient - depending on how low you want to go.

Mms is not only "not the only factor", it isn't a factor at all. Ignore it.

I looked at diaphragm excursion, using this calculator:

http://www.baudline.com/erik/bass/xmaxer.html

For 10 off 1" tweeters, at 95dB @ 1 metre and 400Hz, Xmax is just under 1mm p-p (note the calculator's figure must be multiplied by 2 to get the p-p value). This may vary according to layout.

I'd say that 10 per side would be a minimum, using the right driver (if it's available).
 
#19
Wavecor-TW030WA11-01 Mms .43g Fs 410Hz

Wavecor-TW030WA12-01 Mms .4g Fs 425Hz

These both are 30mm dia so above 12Khz they may beam some what?
I don't think I can hear that high so it doesn't bother me, they sound great to me 😉

Mine are the 11's got them crossed around 1650 3rd order, my baffle is very wide though(4'+ wide boombox with 7"mids and a 10"sub)
 
#20
Harry72 said:
Wavecor-TW030WA11-01 Mms .43g Fs 410Hz

Wavecor-TW030WA12-01 Mms .4g Fs 425Hz

These both are 30mm dia so above 12Khz they may beam some what?
I don't think I can hear that high so it doesn't bother me, they sound great to me 😉

Mine are the 11's got them crossed around 1650 3rd order, my baffle is very wide though(4'+ wide boombox with 7"mids and a 10"sub)
Click to expand...
Expensive, given that absolute minimum quantity needed will be 20.
 
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