Hello everyone!
I have two problem with the design of the crossover.
Please give me some suggestions:
1. According to the characteristics of Accuton Driver , 2nd-order crossover is more suitable 3rd-order?!
2. The best crossover point (2500~3000hz)?
Thank you!
Tweeter C25-6-012:
http://hificompass.com/sites/default/files/documents/c25-6-012.pdf
Mid-Bass C158-6-851:
https://www.falconacoustics.co.uk/downloads/Accuton/Datasheet%20C158-6-851.pdf
I have two problem with the design of the crossover.
Please give me some suggestions:
1. According to the characteristics of Accuton Driver , 2nd-order crossover is more suitable 3rd-order?!
2. The best crossover point (2500~3000hz)?
Thank you!
Tweeter C25-6-012:
http://hificompass.com/sites/default/files/documents/c25-6-012.pdf
Mid-Bass C158-6-851:
https://www.falconacoustics.co.uk/downloads/Accuton/Datasheet%20C158-6-851.pdf
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Well it won't be easy. I don't have much experience with Accuto but the tweeter fs is 740hz and does not seem to have much low freq. and the woofer seems to drop off rather quick after 4khz, you probably have to use 24db roll off for both drivers. It will be tough using 2nd order roll of at 12db slope although it could be done ... I am not sure. As for xover freq., as you said probably 2500 - 3000 depends on the measurement and how the phase can be lined up.
If you could pick another tweeter with better low freq. it will be easy for xover.
As for the tweeter 2.5 to 3Kc/s is perfectly fine with an LR2.
For the mid woofer with the 6 db ? peak at 4.5 Kc/s you will need a somewhat broad parallel notch filter at that frequency with 6 db ? attenuation to pull that down with a LR2 preceding it.
A 5inch mid woofer should easily be workable up to 3Kc/s with little beaming.
C.M
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Based purely on the manufacturer data you'll need something like LR4 slopes; this is generally fairly easy to achieve (it's usually harder to get quality results from low order slopes) but the details depend on the acoustic responses of the drivers on the speaker baffle.
Note the spike in 3rd harmonic distortion for the C158 @ ~1.5KHz. This is likely the result of the cone's 4.5KHz resonant mode, so will need to be heavily suppressed; you may (may) be able to get enough attenuation through a 2nd order electrical + tank or series LCR notch. As I recall from when I last worked with it, the C25 tweeter isn't great < ~2KHz -although described as a 1in [inverted] dome Sd is closer to most 3/4in domes, & it's arguably better used as such. Not the ideal situation, as the tweeter doesn't like going low & the midbass doesn't like going high. Probably about 2KHz - 2.2KHz would be a reasonable compromise with acoustic LR4 slopes, giving acceptable protection to the tweeter & reasonable attenuation to the woofer stopband resonances which will otherwise amplify HD in the intended passband. Steeper slopes would be better in some ways, but that has its own challenges, or a change in either the tweeter to something that can take a slightly lower XO frequency, or woofer to something that can be crossed slightly higher.
Note the spike in 3rd harmonic distortion for the C158 @ ~1.5KHz. This is likely the result of the cone's 4.5KHz resonant mode, so will need to be heavily suppressed; you may (may) be able to get enough attenuation through a 2nd order electrical + tank or series LCR notch. As I recall from when I last worked with it, the C25 tweeter isn't great < ~2KHz -although described as a 1in [inverted] dome Sd is closer to most 3/4in domes, & it's arguably better used as such. Not the ideal situation, as the tweeter doesn't like going low & the midbass doesn't like going high. Probably about 2KHz - 2.2KHz would be a reasonable compromise with acoustic LR4 slopes, giving acceptable protection to the tweeter & reasonable attenuation to the woofer stopband resonances which will otherwise amplify HD in the intended passband. Steeper slopes would be better in some ways, but that has its own challenges, or a change in either the tweeter to something that can take a slightly lower XO frequency, or woofer to something that can be crossed slightly higher.
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Hi Accuton,
I should add, in two-ways sometimes using an asymmetrical crossover is needed in order to achieve proper phase matching. A 2nd order LP and 3rd HP is quite typical. If you can achieve perfect phase matching across the crossover point, then lower part counts is better, although using a staggered or tilted baffle to achieve this last little bit of phase matching is also common.
I would say, build your cabinet, measure, and simulate.
Best,
E
I should add, in two-ways sometimes using an asymmetrical crossover is needed in order to achieve proper phase matching. A 2nd order LP and 3rd HP is quite typical. If you can achieve perfect phase matching across the crossover point, then lower part counts is better, although using a staggered or tilted baffle to achieve this last little bit of phase matching is also common.
I would say, build your cabinet, measure, and simulate.
Best,
E
I would agree with Eric, except to say that it all depends on what works. Don't look at the problem as an electrical solution using "named" electrical filters. It is an acoustic problem that must take the drivers and enclosures acoustical response into consideration. Then use whatever filter does the best job through the transition. Most likely this will not be some "named" filter characteristic in the electrical domain.
My crossovers are asymmetric. 3rd order LP and first order HP, but that's to a waveguide not a direct radiator.
My crossovers are asymmetric. 3rd order LP and first order HP, but that's to a waveguide not a direct radiator.
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