hi,
i have read that you need to run a ribbon tweeter with a capacitor of some description.
can anyone tell me how you go about establishing the value and the placement of such things and the logic behind it?
Fountek NeoCD3.5 horn loaded crossed at 7-9khz (not yet decided)
thanks for your help. 🙂
i have read that you need to run a ribbon tweeter with a capacitor of some description.
can anyone tell me how you go about establishing the value and the placement of such things and the logic behind it?
Fountek NeoCD3.5 horn loaded crossed at 7-9khz (not yet decided)
thanks for your help. 🙂
All tweeters need a cap/crossover. Or are you working on an active system talking about protecting the tweeter? Can you elaborate.
Some people would put a largish cap in series with the tweeter to prevent accidental LF over excursion and/or protection from DC. Protection from DC (mostly in the event of an amp melt down / failure) is a good reason.
As a single xover element it is usually not a steep enough slope.
But the real bottom line is that you need a higher order xover for most true ribbons, they can not be run without some sort of crossover - in case that is what you are thinking?
_-_-bear
As a single xover element it is usually not a steep enough slope.
But the real bottom line is that you need a higher order xover for most true ribbons, they can not be run without some sort of crossover - in case that is what you are thinking?
_-_-bear
i'm just learning about this stuff, so i literally have no idea what is going on.
i was trying to make a full range with no need for a crossover, but my room needs big drivers and it needs a super tweeter to help it not sound flat.
when reading about ribbon tweeters there was a repeated mention of them needing to be used with capacitors, i have no idea what was meant by this.
if i am crossing over from my fullrange unit at say 9khz, what does this mean for the capacitor? basically what do i need to do in order to avoid killing my ribbon.
thanks for replies and sorry for asking dumb questions.
i was trying to make a full range with no need for a crossover, but my room needs big drivers and it needs a super tweeter to help it not sound flat.
when reading about ribbon tweeters there was a repeated mention of them needing to be used with capacitors, i have no idea what was meant by this.
if i am crossing over from my fullrange unit at say 9khz, what does this mean for the capacitor? basically what do i need to do in order to avoid killing my ribbon.
thanks for replies and sorry for asking dumb questions.
several unclear issues here
1. the need of 'protection' cap is uasually brought up in connection with acticve xo, where there are no passive xo cap
2. if you want your fullrange to play up to 6-7khz(or above), a small series cap ought to work
depending on drivers, you might want a series reistor as well
3. might help to know your drivers
I wouldn't recommend just a single series cap for a ribbon tweeter - a 6dB/octave slope is just asking for the ribbon to be damaged even if the nominal crossover frequency is quite high.
With a 6dB/octave slope excursion will continue to increase below the crossover frequency. A 12dB/octave slope will only just maintain excursion flat below the crossover frequency. An 18dB/octave slope is the minimum that will actually reduce excursion below the crossover frequency...
I've used full range drivers and ribbon tweeters a lot, and personally I don't understand the obsession that some have with trying to "avoid" crossovers, as if they are evil incarnate, and the common belief that if no electrical crossover is connected that the design is somehow crossover-less.
The acoustic slopes are what matter, if the low frequency driver rolls off naturally at high frequencies and the high frequency driver rolls off at low frequencies, you have a crossover whether or not there are any electrical components - and usually a very badly adjusted one with tons of overlap and poor phase tracking.
I've tried the full range driver with "no" crossover and super tweeter approach before and while it can add a bit of air to the top it never sounds right to me, somehow slightly disconnected. I've invariably found that a properly designed crossover between the two drivers sounds better.
Just my opinion anyway.
With a 6dB/octave slope excursion will continue to increase below the crossover frequency. A 12dB/octave slope will only just maintain excursion flat below the crossover frequency. An 18dB/octave slope is the minimum that will actually reduce excursion below the crossover frequency...
I've used full range drivers and ribbon tweeters a lot, and personally I don't understand the obsession that some have with trying to "avoid" crossovers, as if they are evil incarnate, and the common belief that if no electrical crossover is connected that the design is somehow crossover-less.
The acoustic slopes are what matter, if the low frequency driver rolls off naturally at high frequencies and the high frequency driver rolls off at low frequencies, you have a crossover whether or not there are any electrical components - and usually a very badly adjusted one with tons of overlap and poor phase tracking.
I've tried the full range driver with "no" crossover and super tweeter approach before and while it can add a bit of air to the top it never sounds right to me, somehow slightly disconnected. I've invariably found that a properly designed crossover between the two drivers sounds better.
Just my opinion anyway.
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I am currently tweaking my new speakers in which I use the Foutek NeoCD2.0 ribbon tweeter.
This setup is fully active with a DSP acting as crossover (Hypex PSC2.400d). So maybe my experience is of some use to you.
The crossover is set to 3100Hz LR8, to avoid interfering with this crossover I used a large capacitor (50uF) as DC protection. In addition to that I placed resistors between this cap and the tweeter (series) to damp any possible ringing effects of the capacitor and the inductance of the transformer of the tweeter and to adjust the tweeter level to my woofers.
If you only use a passive crossover I would recommend at least a third order filter for use with this tweeter..
This setup is fully active with a DSP acting as crossover (Hypex PSC2.400d). So maybe my experience is of some use to you.
The crossover is set to 3100Hz LR8, to avoid interfering with this crossover I used a large capacitor (50uF) as DC protection. In addition to that I placed resistors between this cap and the tweeter (series) to damp any possible ringing effects of the capacitor and the inductance of the transformer of the tweeter and to adjust the tweeter level to my woofers.
If you only use a passive crossover I would recommend at least a third order filter for use with this tweeter..
I'd agree with that. I've managed to stretch a couple of ribbons before with a 2nd order crossover at 4Khz...(at fairly high volume to be fair)
I'm currently using 3rd order at 4Khz with an Aurum Cantus G2 and an 8" full range driver, and getting excellent results. Imaging and smoothness is outstanding, although I have put quite a bit of effort into tweaking the crossover...
I think the directivity control of the small wave-guide on the tweeter gives a much better blend with the full range driver than you would get with say a dome tweeter, allowing a fairly high crossover frequency, and allowing both drivers to work as true point sources through the crossover region. (Minimal baffle diffraction effects through the crossover transition region)
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very very true, in general
ribbons are actually rarely able to be crossed as low as normal domes
commonly known problem
though, many still seem to think they can be crossed low, because they are so much bigger than a dome 😕
and even worse, also the guys who think/read that 6db is good 😱
but crossed very high, a single cap is ok, if its small enough 😀
it does have its advantages you know
especially with fullrange drivers 😉
so the capacitor is used for crossover-less operation of a ribbon tweeter?
so if i'm gently 'rolling in' the super tweeter in the 7-9khz with a high order crossover i don't need the series capacitor?
if i'm getting completely the wrong end of this can someone link me to an idiots version of what you're explaining, or provide a very labelled diagram?
thanks for your help 🙂
so if i'm gently 'rolling in' the super tweeter in the 7-9khz with a high order crossover i don't need the series capacitor?
if i'm getting completely the wrong end of this can someone link me to an idiots version of what you're explaining, or provide a very labelled diagram?
thanks for your help 🙂
If you make a high pass filter for the tweeter you always have a capacitor in series! That's simply how they are constructed..
a simple 3th order filter would be a capacitor in series, inductor to ground, and another capacitor in series. If you want to go 4th order add a inductor to ground, if you want 5th order add another capacitor in series and so on.
a simple 3th order filter would be a capacitor in series, inductor to ground, and another capacitor in series. If you want to go 4th order add a inductor to ground, if you want 5th order add another capacitor in series and so on.
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ah i see! electronics really confuse me which was why i was trying to avoid crossovers etc for now.
so if i was bi-amping the fullrange driver and ribbon tweeter, i only need put in the correct order/slope high pass filter on the ribbon tweeter and all is well?
In theory, but all it would take is one amplifier switch on thud, an accident with the wiring such as unplugging the input to the amp that is feeding the tweeter while its turned on causing 50Hz hum and your ribbon is toast. (Let alone accidentally reversing the cables between the low frequency and high frequency amps - an instant death sentence for the tweeter the first time you turn it on)
Hence any practical active crossover solution with a ribbon tweeter is going to need a series capacitor to provide at least some passive high pass filtering for protection reasons, but that then must be taken account of in the design of the active high pass filter...
That's one good thing about a passive crossover for ribbon tweeters - the protection is inbuilt in the speaker design and impossible to accidentally avoid due to cabling mistakes.
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ok, i think it was a passive crossover that i was intending to use?
is there a piece of software that i can use to botch a design together and get it critiqued?
Not always. Some manufacturers choose to avoid the cap by going with a high sensitivity tweeter is series with a large resistor and in parallel with an inductor.
Speaker Workshop is probably the best free one, but it's got a bit of a learning curve to it.
If I've read this right, your intention is just to add a little sparkle to a full range driver?
That's certainly one, though shunting the tweeter's impedance peak at resonance with the inductor has defensible advantages in the filter slope region. Offset by other disadvantages though, making it just another, limited, technique in the tool kit.
Yes that could be benificial, but in the case of a ribbon tweeter with a very flat impedance curve I don't see the benefits. Please correct me if I am wrong, but I just don't see it..
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