I use this one, it works fast enough for both on/off because the power is directly from AC18V.
New Assembled UPC1237 Mono Speaker Protection Board | eBay
SIT is better because it dissipates less heat
, and sadly, I have to use Hypex for woofers in summer.Horn and Aleph is surely a great combination. I have had Pass Aleph 5 for another horn, and decided to build 6 ch AJ with a lot of confidence.
Yes, I understand that which is why I didn't want it to be a pole of the crossover.
SIT is better because it dissipates less heat
A series capacitor would eliminate or reduce damping of a tweeter, but lacking a horn, would not result in as much diaphragm movement resultant from exposure to high SPL low frequency.
Mpa's concern is from the amplifier side, my bringing up the capacitor problem in this situation was just for "completion"
Art
Myth?
If you use 33 μF cap for 1st order, it inserts 7.66 Ω at crossover.
Not much damping there.
If you spend a lot and use 100 μF, as shown in sketch, it inserts less impedance.
Either ways will neuter your high damping factor amp.
If we are talking about a woofer, we could add Some damping to its cabinet.
Not so with a tweeter nor a CD.
There are better ways to add passive DC protection without crippling damping.
If you use 33 μF cap for 1st order, it inserts 7.66 Ω at crossover.
Not much damping there.
If you spend a lot and use 100 μF, as shown in sketch, it inserts less impedance.
Either ways will neuter your high damping factor amp.
If we are talking about a woofer, we could add Some damping to its cabinet.
Not so with a tweeter nor a CD.
There are better ways to add passive DC protection without crippling damping.
Normally the impedance peak is cut using a RLC filter. (It could also be done digitally.)
The driver doesn't change when the source impedance increases. The load and source impedance interaction does. That requires attention so you restore Voltage drive. This is not the same as some quality going out the window.
The driver doesn't change when the source impedance increases. The load and source impedance interaction does. That requires attention so you restore Voltage drive. This is not the same as some quality going out the window.
Yes. I said so myself
EDIT:I see a lot of worry about HF drivers damping.
My point is I guess all were designed, developed and USED for DECADES with passive crossovers in mind, and using active crossovers + separate SS amplifiers is just the strawberry on the cake, nice to have but not strictly necessary so no point in over worrying about it.
Since *any* passive crossover will MURDER ultra high SS amp damping it´s a logic conclusion high damping is not indispensable, and that saying it mildly.
To boot HF drivers are OFTEN used (in a passive criossover that is) with some attenuating resistor in series and designers also know that.
Do you see ANY Factory datasheet asking for high damping drive of their units?
I don´t
Of course, If anybody has some serious Factory datasheet , manual or brochure stating that, please feel free to post a copy here.
Until then ......
Last edited:
Art,
Thank for your answer.
To be honest i was considering the use for my own case with my mains which use rare/unobtainable drivers ( tweeter being the most fragile). The point you raised i thought was a way to consider the situation i never contemplated before (to get rid of the blocker cap on the tweeter).
When talking about damping factor i automaticly think about grip and control over woofer and not the benefits it may have had higher in freq!
I must admit it took me multiple reading of message you linked to get the point that damping factor help to protect the Tad from a mechanical/ acoustical coupling.
Horn CD being a transducer it works in both ways equally ( as emiting sound and capting it) and horn loading make the issue more severe.
I never considered this kind of issues could be faced before but it makes perfect sense.
So nice to have access to this kind of knowledge and special case exposure. Thank you ( and others) to put this into light.
Thank for your answer.
To be honest i was considering the use for my own case with my mains which use rare/unobtainable drivers ( tweeter being the most fragile). The point you raised i thought was a way to consider the situation i never contemplated before (to get rid of the blocker cap on the tweeter).
When talking about damping factor i automaticly think about grip and control over woofer and not the benefits it may have had higher in freq!
I must admit it took me multiple reading of message you linked to get the point that damping factor help to protect the Tad from a mechanical/ acoustical coupling.
Horn CD being a transducer it works in both ways equally ( as emiting sound and capting it) and horn loading make the issue more severe.
I never considered this kind of issues could be faced before but it makes perfect sense.
So nice to have access to this kind of knowledge and special case exposure. Thank you ( and others) to put this into light.
Indispensable it is not, for sure.
And the popularity of certain amplifier's design philosophy is in line with your thoughts ( N. PASS products come to mind as well as some tube based design). And with some kind of loudspeakers it is even what the doctor have ordered.
That said an high damping factor amplifier in a case of multiamp active filtering system does have obvious advantages for some ( sub and low) ways. Of course it won't appeal to everyone ( ever heard a Crown 'studio reference2'? It does have control over lower registers -to say the least!- but in turns some find it too 'dry' sounding...).
The case pointed by Art is another special case where it is interesting too ( and for me even more as it is counterintuiting for my way of thinking).
Do you see ANY Factory datasheet asking for high damping drive of their units?
I don´t
Of course, If anybody has some serious Factory datasheet , manual or brochure stating that, please feel free to post a copy here.
Until then ......
You won't find datasheet asking for current drive amplifier neither but that won't say it is not used even by brands doing drivers and loudspeakers ( ATC mid dome drivers comes to mind).
Overall this is another case pointing to 'each case it's own answer', or 'devil is in the detail'. At least to me.
( Don't get me wrong Jm FAHEY, i'm with you and agreed to your point. But in a case of a Be CD there is some particular needs which 'ask' for a dedicated answer not a general approach).
I really like this place and members here as this kind of info is not wildely spread ( afaik) and displayed to others.
This is not correct. A capacitor selected for the existing crossover frequency will add addition slope to the tweeter crossover and cause additional phase shift.
An octave minimum or two below the crossover frequency is my recommendation.
The primary goal is to keep DC out of your driver not to make the capacitor part of the crossover.
DT
Well, I'd say it was correct, as the suggestion was to make it part of the (overall) crossover (slope), so that the active crossover would need a less steep slope, hence the suggestion to take new measurements with that cap in place. After all, for a decent crossover performance one would need to shape the acoustical output. Not selecting a named crossover in software. So it could work to make the protection cap part of it.
It would limit the possibilities to play with the cut-off frequency.
It would limit the possibilities to play with the cut-off frequency.
Last edited:
Hello,
If there is already crossover in line between the amplifier output and the speaker there is already a capacitor protecting the HF driver. An additional capacitor would not be needed.
The OP tells us that this an active crossover Bi-amp setup, why make the protection capacitor part of the crossover with the problems of phase shift and the like, in the middle of the 300 to 3000 Hz frequency range, the goal of bi-amping is to avoid all that stuff. It is a mistake to add a inline capacitor in the middle of the crossover frequency.
Thanks DT
If there is already crossover in line between the amplifier output and the speaker there is already a capacitor protecting the HF driver. An additional capacitor would not be needed.
The OP tells us that this an active crossover Bi-amp setup, why make the protection capacitor part of the crossover with the problems of phase shift and the like, in the middle of the 300 to 3000 Hz frequency range, the goal of bi-amping is to avoid all that stuff. It is a mistake to add a inline capacitor in the middle of the crossover frequency.
Thanks DT
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.