I've always found this topic to be strange, since ribbons are... well... strange.
I would like a more serious crossover than a simple cap.... it seems a little bit cheap.
I know that ribbons only need a cap, but a resistor maybe? The FQ cutoff would be around 2.5K. I was thinking about a 30uF cap?
And I have no idea of what value for the resistor
I'll use the Fountek NEO X 2.0
I would like a more serious crossover than a simple cap.... it seems a little bit cheap.
I know that ribbons only need a cap, but a resistor maybe? The FQ cutoff would be around 2.5K. I was thinking about a 30uF cap?
And I have no idea of what value for the resistor
I'll use the Fountek NEO X 2.0
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A 30 uF cap seems quite high. Too high a value which would put the knee well below 1 kHz I'm guessing - not knowing the tweeter's impedance. Can you share the brand/model and specs? You will get a lot more help if you do.
A series or L-pad resistor network is only needed if there is an efficiency miss-match with the midrange or woofer.
You may want to consider a parallel coil to form a 2nd order network for the tweeter to protect it from high levels of distortion or, worse yet, damage.
A series or L-pad resistor network is only needed if there is an efficiency miss-match with the midrange or woofer.
You may want to consider a parallel coil to form a 2nd order network for the tweeter to protect it from high levels of distortion or, worse yet, damage.
A resistor dont add any extra crossover effect - it dampens the the ribbon for all frequencies. If you wish to apply a steeper filter (which is a good idea), toy with the page below. Add the driver impedance (use 8 ohm for the Fountek (put 8 alos for low pass or it wont calculate)) and the wanted crossover (2300 hz recommended) frequency an you get the values and a schematic (hit Additional information) for the corresponding filter. If you still have to much output from your ribbon compared to the lower frequencies then it's time to bring out the resistors - but thats an other story (use L-pad calculator on same page). Good luck!
You want a High-Pass filter of 2nd (Linkwitz-Riley) (or 3rd) order.
Speaker Crossover Calculators by V-Cap
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You want a High-Pass filter of 2nd (Linkwitz-Riley) (or 3rd) order.
Speaker Crossover Calculators by V-Cap
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Hi Jeremy!
Why don't you grab XSim along with a chart ingesting tool like SPLCopy so you can model this. I find playing with models a better way to explain and learn about this than math.
Some speakers (rarely) are exactly that, two way systems with a single cap in the tweeter. You should not feel obligated to reach a target number of parts, or crossover slopes. Integration between the drivers is what matters most. Sometimes it takes 4 parts, sometimes 12.
The thing with delicate tweeters like ribbons is they usually recommend at least a 2nd order crossover at X frequency. I'd review the specs.
Best,
Erik
Why don't you grab XSim along with a chart ingesting tool like SPLCopy so you can model this. I find playing with models a better way to explain and learn about this than math.
Some speakers (rarely) are exactly that, two way systems with a single cap in the tweeter. You should not feel obligated to reach a target number of parts, or crossover slopes. Integration between the drivers is what matters most. Sometimes it takes 4 parts, sometimes 12.
The thing with delicate tweeters like ribbons is they usually recommend at least a 2nd order crossover at X frequency. I'd review the specs.
Best,
Erik
I'm using a Fountek NEO X2.0. It's 8 Ohm, you can find the specs online.
I think at this point I only need a ~20uF cap.
If you have suggesions, please, go ahead
Need a bit more detail on this..... What resistor you are thinking of? A series resistor for level matching, or a parallel one for impedance smoothing?
Ribbons are strange animals as far as crossover design is considered. All real ribbons (like the Founteks) employ an impedance matching transformer in their housing, so XO design is a bit more complicated than in the case of traditional -moving coil- tweeters.
In any case 30 uf seems a bit too much for crossing that driver at 2.5k. Not to mention the fact, that first order crossovers are not really recommended with those kind of tweeters. Based on my experience with the Neo CD1, I would recommend a second order filter, with a series cap of around 10-15 uF, and a parallel coil around 0.5-0.8 mH. Those are ballpark values for a 2nd order LR type filter.
Also it does not hurt to put a parallel resistor across the terminals , something like 22-33 ohms/ 10 watts, to somewhat compensate the rising impedance of the matching transformer.
Ribbons are strange animals as far as crossover design is considered. All real ribbons (like the Founteks) employ an impedance matching transformer in their housing, so XO design is a bit more complicated than in the case of traditional -moving coil- tweeters.
In any case 30 uf seems a bit too much for crossing that driver at 2.5k. Not to mention the fact, that first order crossovers are not really recommended with those kind of tweeters. Based on my experience with the Neo CD1, I would recommend a second order filter, with a series cap of around 10-15 uF, and a parallel coil around 0.5-0.8 mH. Those are ballpark values for a 2nd order LR type filter.
Also it does not hurt to put a parallel resistor across the terminals , something like 22-33 ohms/ 10 watts, to somewhat compensate the rising impedance of the matching transformer.
Thanks for the replies guys.
I actually deisgn and build speakers... and sell them if I am that lucky.
However I've never used a ribbon, but I need a "Top of the line" project for an eventual Kickstarter project.
Anyway, I use BassBox and XOver Pro for my work, I was just curious.
Because basically I can deisgn a normal 2nd order Butterworth crossover with a coil and a cap and call it a day.
Good to know, thanks!
I actually deisgn and build speakers... and sell them if I am that lucky.
However I've never used a ribbon, but I need a "Top of the line" project for an eventual Kickstarter project.
Anyway, I use BassBox and XOver Pro for my work, I was just curious.
Because basically I can deisgn a normal 2nd order Butterworth crossover with a coil and a cap and call it a day.
Good to know, thanks!
If you had studied the available impedance trace in the product documentation, you had found that it is a very easy load and that standard calculation is applicable. 30uF is really off the chart 😉
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Oh I know, I think you're conflating a piezo with a ribbon, piezos don't need a cap, because they are a capacitor already, they need a resistor to stop presenting as a purely capacitative load to the amp.
There' nothing really strange about a ribbon, it's still a coil in a magnetic field, just that the coil and the "cone" are the same thing and the general rules apply, ie, crossover an octave over Fs, but because there's no cone they are much lighter and more fragile, which is terrific for effortless music, they have a well deserved reputation for that, but also for falling apart from merely opening and closing the room door, which is why manufacturers recommend a minimum of second order crossover for their ribbons, ie a coil and a cap.
Your cap size should be of the order of 5uF, not 20 or 30uF.
Not meaning to be rude but as a speaker designer this should be bread and butter stuff for you.
And I certainly don't want to put you off experimenting with ribbons because getting it right can be musically very very satisfying, but it is like when making food with very expensive ingredients, amazing results are not guaranteed at all, and you could make things worse, in the sort of way a 4K TV will reveal a news reader's really awful skin.
I should add, that if you are going to the expense and trouble of working with ribbons you should consider going active, it'll be far easier and actually cheaper to get a good result from an active crossover then fiddle around for 6 months buying expensive caps and coils.
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