What exact capacitor value would you recommend for a first order slope at 1,200Hz? I have never done a first order slope that low, and do not fully understand the consequences of the rising impedance as the frequency lowers. I am use to using 2nd order slopes without trying to get the lowest frequency possible. Under ordinary circumstances, my tendency would be to use a 1,500 Hz second order slope or higher for that tweeter so the impedance rise is not near the crossover point. In this case, I am willing to experiment in uncharted territory.
https://www.parts-express.com/pedocs/specs/264-1678--peerless-da32tx00-08-spec-sheet.pdf
https://www.parts-express.com/pedocs/specs/264-1678--peerless-da32tx00-08-spec-sheet.pdf
Why not use a passive line level crossover (PLLXO) and a separate amp?
TLS.org | Passive Line-Level Crossover
Just a small capacitor and a resistor placed in the interconnect cable to get you the first-order attenuation. By going line-level, you circumvent the problem of dealing with the impedance variations of the driver.
Kurt
TLS.org | Passive Line-Level Crossover
Just a small capacitor and a resistor placed in the interconnect cable to get you the first-order attenuation. By going line-level, you circumvent the problem of dealing with the impedance variations of the driver.
Kurt
I assume you may go beyond the Xmech if the high pass attenuation is too much smooth.
Maybe using a calculator to know what max spl at Xmax is able the unit with a 6 db octave attenuation may help ? But the destruction there is an acoustic null at the right feet of the resonance impedance rise, no ?
So what is the max spl needed at the frequency you want the tweeter to be XO and follow the mid, knowing that the 6 db attenuation per octave will not go to the Xmech or Xmax ?
Again both the DA25 & DA32 TXs have high excursion but certainly distorts below the 1500 hz talked with both tweeters. Not saying that heat of the voice coil is not wanted (holes in power response and distortion).
If such a driver was able to survive to a first order at 3000 to 3500 it could be an exception already...
Maybe using a calculator to know what max spl at Xmax is able the unit with a 6 db octave attenuation may help ? But the destruction there is an acoustic null at the right feet of the resonance impedance rise, no ?
So what is the max spl needed at the frequency you want the tweeter to be XO and follow the mid, knowing that the 6 db attenuation per octave will not go to the Xmech or Xmax ?
Again both the DA25 & DA32 TXs have high excursion but certainly distorts below the 1500 hz talked with both tweeters. Not saying that heat of the voice coil is not wanted (holes in power response and distortion).
If such a driver was able to survive to a first order at 3000 to 3500 it could be an exception already...
I made some simulations and these are my findings.
With 16uF cap in series that impedance rise toward tweeters Fs has huge contra effect on crossover rollof. At 1200 Hz its -4dB but at Fs almost no attenuation.
Reducing the value of cap only gives more overal attenuation, but no change of slope shape. For eg. 8uF gives -7db@1200Hz and -3db@Fs. This cant work properly.
In next step I went back to 16uF in series, but with some simple resistor in paralell with tweeter to reduce impedance bump @Fs. Value should be low enough to give good effect, but high enough not to drop tweeters impedance to far. I tried values from 24 to 47 Ohms and found 36 Ohm most suitable.
That combination gives -4dB@1200Hz and -3dB@Fs. Thats a step not a slope, but in this case exactly what is needed beacuse tweeter response shows rollof below 1000Hz with about -4dB@Fs.
So, combined response of crossover step + tweeter rollof gives -4dB@1200Hz and -7dB@Fs which is correct 6dB slope with additional 1dB attenuation.
Below Fs rollof is much steeper as combination of rising Xcap + falling tweeters impedance.
36 Ohm in paralell with tweeter reduces its minimal impedance value to about 6 Ohms which is acceptable.
For woofer, 1mH inductor in series gives very nice result. Simulation shows proper 6dB slope with additional 2dB attenuation caused by voice coil inductance.
This is favourable in this case, beacuse woofer response shows 3dB rise from 1500 to 3000Hz, so additional attenuation will compensate that.
DC resistance of inductor in simulations was 0,5 Ohms and its not critical.
Only unexpected result is tweeter polarity.
Simulation shows tweeter polarity must be reversed in order to get proper crossover function.
Compared to original arrangement with 33uF in series with tweeter this one reduces power that has to be handled by tweeter for more than 2 times at 1200Hz and Fs, and more than 6 times at 0,5Fs.
So there should be no problem of reaching normal listening levels.
Please note Iam not speaker engineer, but if you wish to experiment with this it should give some nice results:
1mH in series with woofer
16uF in series with tweeter
36 Ohm in paralell with tweeter
tweeter with reversed polarity
With 16uF cap in series that impedance rise toward tweeters Fs has huge contra effect on crossover rollof. At 1200 Hz its -4dB but at Fs almost no attenuation.
Reducing the value of cap only gives more overal attenuation, but no change of slope shape. For eg. 8uF gives -7db@1200Hz and -3db@Fs. This cant work properly.
In next step I went back to 16uF in series, but with some simple resistor in paralell with tweeter to reduce impedance bump @Fs. Value should be low enough to give good effect, but high enough not to drop tweeters impedance to far. I tried values from 24 to 47 Ohms and found 36 Ohm most suitable.
That combination gives -4dB@1200Hz and -3dB@Fs. Thats a step not a slope, but in this case exactly what is needed beacuse tweeter response shows rollof below 1000Hz with about -4dB@Fs.
So, combined response of crossover step + tweeter rollof gives -4dB@1200Hz and -7dB@Fs which is correct 6dB slope with additional 1dB attenuation.
Below Fs rollof is much steeper as combination of rising Xcap + falling tweeters impedance.
36 Ohm in paralell with tweeter reduces its minimal impedance value to about 6 Ohms which is acceptable.
For woofer, 1mH inductor in series gives very nice result. Simulation shows proper 6dB slope with additional 2dB attenuation caused by voice coil inductance.
This is favourable in this case, beacuse woofer response shows 3dB rise from 1500 to 3000Hz, so additional attenuation will compensate that.
DC resistance of inductor in simulations was 0,5 Ohms and its not critical.
Only unexpected result is tweeter polarity.
Simulation shows tweeter polarity must be reversed in order to get proper crossover function.
Compared to original arrangement with 33uF in series with tweeter this one reduces power that has to be handled by tweeter for more than 2 times at 1200Hz and Fs, and more than 6 times at 0,5Fs.
So there should be no problem of reaching normal listening levels.
Please note Iam not speaker engineer, but if you wish to experiment with this it should give some nice results:
1mH in series with woofer
16uF in series with tweeter
36 Ohm in paralell with tweeter
tweeter with reversed polarity
I made another simulation which shows maximum allowable voltage at crossover input for tweeters Xmax and Pmax.
With 16uF in series and 36 Ohms in parallel its around 26 volts at Fs, and higher below and above.
At 8 Ohm impedance thats some 85 Watts, so it seems woofer power handling is limiting factor here. I would take that with good amount of caution, but 40 Watts should be safe for this combination giving 105dB SPL at 1m. More than enough for home listening.
With 16uF in series and 36 Ohms in parallel its around 26 volts at Fs, and higher below and above.
At 8 Ohm impedance thats some 85 Watts, so it seems woofer power handling is limiting factor here. I would take that with good amount of caution, but 40 Watts should be safe for this combination giving 105dB SPL at 1m. More than enough for home listening.
Well done and thanks for the tip.
What was please the frequency cut-off for 16 uF, i.e. the impedanceof the DA25TX there ?
What was please the frequency cut-off for 16 uF, i.e. the impedanceof the DA25TX there ?
The description in the article is pretty confusing. The upper woofer loses level from around 600Hz, but not "pretty sharp". As usual with a 6dB low-pass, the -6dB point is around 1kHz.
In order to provide a clean response together the crossover frequency of the tweeter has to be around 2kHz.
I think the specified 575Hz is nonsense.
In order to provide a clean response together the crossover frequency of the tweeter has to be around 2kHz.
I think the specified 575Hz is nonsense.
i wouldnt try to replicate anythng spatial audio makes, their designs are really dumb imo. theres no way they can work.
Darn, I was hoping by now there would be some good experience with this tweeter. CSD, distortion and subjective viewpoints. Is it more like the Be domes, or more like the SB ceramics? What does it take to manage it's breakup? Is it better used as a midrange, say 1500 to 8K allowing a shallow LP filter? Heck, does it have the displacement to work at reasonable distortion below 2K? That 1/8 inch is a lot more area where a 1 inch just runs out of poop below 2200 or so.
Lol.....you guys are still going pretty hard at all this from the super geek technical end of things.......but at the end of the day, this is music which is a pretty subjective art form so hey.....maybe the design has a niche and plays wonderfully?......not everything in art can or should be scientific.....imagine if Hendrix said ‘nah, the guitar notes need to be clean and free of distortion’. Come on fellas.....lighten up will ya.
Then there is the thing where that tweeter isn't stock DA32TX but modified by Tymphany. From manufacturers interview i watched few days ago, he specifically asked from Tymphany that the tweeter holds 25W at 500Hz and up (adding ferrofluid to the magnetic gap, different former for voice coil, different suspension etc.). Let me remind you that stock DA32TX has Xmax=1mm with 4.5mm gap height. It is crossed at about 500-600Hz to woofer (nothing new, we know that people do that with 15" woofers and horns all the time).
He looks at that modified driver as mid-tweeter - which is nothing new again since FAST is quite popular. Highpass applied actually functions like tweeter protection circuit since it doesn't change frequency response. There is large series capacitor to the tweeter - if he added impedance flattening notch, i'm starting to think it is doable. Different approach that's for sure but by no means crazy.
Given that there is massive loss of sensitivity for woofers in OB, i'm guessing that this loudspeaker sounds quite well up to 20-25 watts. Even more, since it is crossed pretty low my guess it that the directivity isn't too shabby.
So, as an end product you end up with probably 90dB/W/1m-ish that can withstand 25W of input. Now use your simulators to see how loud that gets at 25W.
Smart guy 🙂
He looks at that modified driver as mid-tweeter - which is nothing new again since FAST is quite popular. Highpass applied actually functions like tweeter protection circuit since it doesn't change frequency response. There is large series capacitor to the tweeter - if he added impedance flattening notch, i'm starting to think it is doable. Different approach that's for sure but by no means crazy.
Given that there is massive loss of sensitivity for woofers in OB, i'm guessing that this loudspeaker sounds quite well up to 20-25 watts. Even more, since it is crossed pretty low my guess it that the directivity isn't too shabby.
So, as an end product you end up with probably 90dB/W/1m-ish that can withstand 25W of input. Now use your simulators to see how loud that gets at 25W.
Smart guy 🙂
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I’m finished with a wave guide of the 1” version. About to put it all back together in a few days.
Of course...
Clayton Shaw of Spatial Audio | Ep 43 - YouTube
It's quite long but well worth a watch.
Clayton Shaw of Spatial Audio | Ep 43 - YouTube
It's quite long but well worth a watch.
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