Hey,
I would love to get some help with a simple crossover for the drivers below:
B&C DE10 in 18sound XT1086
B&C 8PE21
Could it work with a low value cap on the tweeter for CD compensation and as an appropriate high pass, and then just cross the midrange driver steep enough to match the natural roll of of the tweeter at aprox 1500 hz?
Thanks
I would love to get some help with a simple crossover for the drivers below:
B&C DE10 in 18sound XT1086
B&C 8PE21
Could it work with a low value cap on the tweeter for CD compensation and as an appropriate high pass, and then just cross the midrange driver steep enough to match the natural roll of of the tweeter at aprox 1500 hz?
Thanks
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Do you have the impulse measurements?
We could sim something, I have been playing with Speaker Workshop for the past little while and its getting to be pretty easy.
btw, why the DE10? I do not think it place nice below 2kHz? Of course with th 8" woofer you can easily set and XO above 2KHz so its not a big deal.
We could sim something, I have been playing with Speaker Workshop for the past little while and its getting to be pretty easy.
btw, why the DE10? I do not think it place nice below 2kHz? Of course with th 8" woofer you can easily set and XO above 2KHz so its not a big deal.
It falls of naturally around the area where an 8 incher matches the dispersion of the horn
Don't have impulse measurements. I don't need an "high-end" crossover, just "hi-fi" Then something like a 2.2 uF cap for the tweeter and a simple XO for the 8" woofer
I only say 2.2 uF because that is what I used recently with my QSC waveguides. You will need an Lpad to though. Even "Hi Fi" is a little complex and needs measurements, no?
I enjoy this type of project though, I will follow the thread!
I only say 2.2 uF because that is what I used recently with my QSC waveguides. You will need an Lpad to though. Even "Hi Fi" is a little complex and needs measurements, no?
I enjoy this type of project though, I will follow the thread!
Then something like a 2.2 uF cap for the tweeter and a simple XO for the 8" woofer
I only say 2.2 uF because that is what I used recently with my QSC waveguides. You will need an Lpad to though. Even "Hi Fi" is a little complex and needs measurements, no?
I enjoy this type of project though, I will follow the thread!
Cool
How should the crossover for the woofer look? I understand we need to flatten impedance and need a pretty steep slope to match the steep rolloff of the tweeter. But the electrical part, components and such I have noe clue..Measurements are on the manufacturer site here. Would be great if someone could take the trouble and just give me the values needed to flatten the impedance and to make a 3 or 4th order low pass...
Try this for a 3rd order XO.
Speaker Crossover Network Design Formulas & Calculator (3rd Order Butterworth)
Speaker Crossover Network Design Formulas & Calculator (3rd Order Butterworth)
I've figured I need to build a series crossover, because my tube amp don't like low impedances too much...
Therefore I would be really greatfull if someone could tell me what values I need to:
- 1st order filter at 8khz on the tweeter
- Flatten impedance on the mid
- 2nd order filter at 1,5 khz on the mid
How would the crossover look like?
Thanks
Therefore I would be really greatfull if someone could tell me what values I need to:
- 1st order filter at 8khz on the tweeter
- Flatten impedance on the mid
- 2nd order filter at 1,5 khz on the mid
How would the crossover look like?
Thanks
Thanks
I tried to find out what values I need to flatten impedance, but a little too advanced math there for me...
Its not that hard.
1/R = 1/R1 + 1/R2
R1 = the impedance value at any point on the impendance curve
R2 = the resistor you place parrallel to the driver
Here are some hypothetical numbers using a 16 ohm resistor. I do not know your impedance curve but this should give you an understanding.
At 200 Hz, the impedance is 5 || 16, which is 4 ohms
At 1kHz, it's 21 || 16 = 9 ohms
At 2kHz it's 12 || 16 = 7 ohms
At 5kHz it's 8 || 16 = 5 ohms
The 21 ohms gets reduced to 9 ohms but the 5 ohms point on the curve only gets reduced to 4 ohms.
The 16 ohm resistor flattened the curve very well.
Hi Defo, How many woofers are you planning on having to go with the tweeter? There is a BIG difference in efficiency between the woofer and the tweeter. roughly 9db! even running two woofers in parallel will only buy you a theoretical 6db efficiency gain, the tweeter will need to be padded down.
I'm also confused about the 8K and 1.5K... I really don't think that you can do a first order crossover on this tweeter and match it to this woofer. The resonant freq of the tweeter is nearly 2Khz so I'd say as a rule of thumb you would have to go at least 4K and probably 6K (with a zobel on the tweeter to flatten it's resonant peak) to get away with a 1st order crossover. After that you are going to need to try and stretch the 8" up to 4Khz perhaps a notch filter on the peak at about 2.8Khz might work, I'm doing something similar on my speakers, but my tweeters resonant freq is about 900Hz.
a 2.2uf cap I would think would give you a 1st order crossover freq somewhere around 10Khz based on textbook values for the tweeter impedance of about 7 ohms (based on the impedance plot)!
Tony.
I'm also confused about the 8K and 1.5K... I really don't think that you can do a first order crossover on this tweeter and match it to this woofer. The resonant freq of the tweeter is nearly 2Khz so I'd say as a rule of thumb you would have to go at least 4K and probably 6K (with a zobel on the tweeter to flatten it's resonant peak) to get away with a 1st order crossover. After that you are going to need to try and stretch the 8" up to 4Khz perhaps a notch filter on the peak at about 2.8Khz might work, I'm doing something similar on my speakers, but my tweeters resonant freq is about 900Hz.
a 2.2uf cap I would think would give you a 1st order crossover freq somewhere around 10Khz based on textbook values for the tweeter impedance of about 7 ohms (based on the impedance plot)!
Tony.
Hi Defo
I have no comment on the series crossover and impedance flattening...but how on earth is the cap between 1.5K-8k going to be filled,is it still a 2way crossover you are designing or something else? I hope it's just a typo
The gap is filled by the horn loading, here is a measurement with a cd horn attached. With the 1,5 uF cap the sensitivity is down to 98 db/w, which mates perfectly with the midrange. Downside is a small rise in the top octave, but nothing too serious. So the next step is to cross the midrange over where the tweeter rolls off by it self.
Thanks, so a 16 ohm resistor in paralell with the driver post crossover should work? I have meant to read that one needs both a cap and resistor in paralell with the driver, but I may have misunderstood.
That's cool,the horn makes a huge difference,more than I would have expected.
Good luck with the build
I didnt look at the specific driver I was using one of mine as an example on how the calculations work.
Did you post the impedance curve of your driver?
Notch filter or a low pass filter high up might fix that rise?
Its funny reading Geddes comments that there is more to this then a single cap. I know the the single cap is a great start to getting a pretty flat response with the horn.
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