I'm leaning towards trying a 2-way passive since it's relatively simple and inexpensive, and I'll learn along the way.
I'm thinking the tweeter should be on a 2nd or 3rd order and so should the midrange to avoid getting into cone breakup area (should I go with a 1st order).
AllenB suggested the tweeter be on a higher order than the midrange. So 3rd order for tweeter and 2nd order for midrange.
3rd order Butterworth for this tweeter, at 2500Hz:
Here's what I envision as next steps:
I'm thinking the tweeter should be on a 2nd or 3rd order and so should the midrange to avoid getting into cone breakup area (should I go with a 1st order).
AllenB suggested the tweeter be on a higher order than the midrange. So 3rd order for tweeter and 2nd order for midrange.
3rd order Butterworth for this tweeter, at 2500Hz:
C1=8.66uF
C2=25.98uF
L1=0.23mH
I've asked a potential supplier what he has available around these values.C2=25.98uF
L1=0.23mH
Here's what I envision as next steps:
- Get feedback here and adjust this plan
- Get parts for the tweeter network (above) and for a 2nd order LR network for the midrange without the horn
- Build 3rd order network for tweeter, measure frequency response, confirm it's doing what I expected.
- Build horn for the midrange, measure, re-run numbers for the network.
I don't think I said as much as that. Have you decided how those horns are going to fit together?
I think it's premature to expect to finalise a crossover without first building the speaker. It could be simulated, but I think it would be easier and more accurate to use actual results (unless the design process is thorough), and it's something I'd do either way.
If you're just looking to get the tweeter operating so you can begin assessing it by listening then perhaps you could try a second order filter at a moderate frequency (I hear 2k is not unreasonable for the TPL) though I'd expect you'd want to vary this filter considerably to see what the driver can do, keeping in mind that it's difficult to tell too much without a properly blended lower range.
When it comes to measuring it might be more helpful to use a bare minimal crossover if any so it gives you useful data for the sim.
If you're just looking to get the tweeter operating so you can begin assessing it by listening then perhaps you could try a second order filter at a moderate frequency (I hear 2k is not unreasonable for the TPL) though I'd expect you'd want to vary this filter considerably to see what the driver can do, keeping in mind that it's difficult to tell too much without a properly blended lower range.
When it comes to measuring it might be more helpful to use a bare minimal crossover if any so it gives you useful data for the sim.
Over the weekend I spent some time looking into this. I'm taking away using Bagby's Passive Crossover Designer tool is probably my best alternative. Would you agree?
And to properly use the tool I need to measure my drivers, export the frd and zma files to load into the tool, and take it from there. Is that a good path?
And to properly use the tool I need to measure my drivers, export the frd and zma files to load into the tool, and take it from there. Is that a good path?
May I ? I don't think it's a bad idea ! The caps model will make more difference here than 0.4 uF imho ! But you should be able to find 9 uF 1 or 2% acuracy the day you're will be defintly ok with your filter and when it will be your last priority...
Very good tutorial on the PCD toolset.
Simple Loudspeaker Design ver2 Dave Dal Farra
http://audio.claub.net/software/DaveDalFarra/Simple Loudspeaker Design ver2.pdf
The free schematic-based crossover tool Xsim is popular for horn speakers which break the standard box flow.
Good.
I'll do the TPL first. How should I set up driver and mic for the purpose of measuring response towards crossover design?
Does it matter where I place the TPL?
Should I place the mic 10cm from the AMT, on-axis, in the middle of the AMT height? Or further away?
Gate the measurement? By how much?
I'll do the TPL first. How should I set up driver and mic for the purpose of measuring response towards crossover design?
Does it matter where I place the TPL?
Should I place the mic 10cm from the AMT, on-axis, in the middle of the AMT height? Or further away?
Gate the measurement? By how much?
Here's the measured TPL-150H response.
TPL was mounted vertically, away from reflecting surfaces. Mic was inside the waveguide and 3" away from the front of the AMT, on axis, in the middle. I used REW, from 1 to 20kHz, gated with FDW of 10 cycles.
Is this OK to use as input into Bagby's Passive Crossover Designer?
TPL was mounted vertically, away from reflecting surfaces. Mic was inside the waveguide and 3" away from the front of the AMT, on axis, in the middle. I used REW, from 1 to 20kHz, gated with FDW of 10 cycles.
Is this OK to use as input into Bagby's Passive Crossover Designer?
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I built a dummy rectangular tractrix horn for the M5N12 out of foam, and measured the driver. Response is plotted below. It looks so good it is making me wonder if I'm measuring appropriately.
Mic was set 12" from the horn mouth, gated FDW at 10 cycles, response smoothed at 1/48.
It is very suspicious to me the exact same response as the TPL was measured, even the ripples at 4-5kHz.
So assuming the measurement was right, next step is to input both frd ccurves into the Passsive Crossover Designer. BUT, do measurements look right?
Thanks in advance for the input!
Mic was set 12" from the horn mouth, gated FDW at 10 cycles, response smoothed at 1/48.
It is very suspicious to me the exact same response as the TPL was measured, even the ripples at 4-5kHz.
So assuming the measurement was right, next step is to input both frd ccurves into the Passsive Crossover Designer. BUT, do measurements look right?
Thanks in advance for the input!
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