"A 12V/5W car tail light bulb is about right for a 8R tweeter"
A 211-2 works best for tweeters with 25mm coils, a 1156 works best with 44mm coils, and 1141 with 35mm coils.
A 211-2 works best for tweeters with 25mm coils, a 1156 works best with 44mm coils, and 1141 with 35mm coils.
Or just use senses and don't go max on volume with a 500 W amp. I mean, any semiconductor or other protection circuit will deteriorate sound quality.
"Or just use senses and don't go max on volume with a 500 W amp. I mean, any semiconductor or other protection circuit will deteriorate sound quality. "
Please explain how the deterioration occurs before the protection is active.
"They have great horn tweeters and they use the same diaphragms as Klipsch Heresy II's."
The 10W rated 211-2 will protect that tweeter very well.
The original Heresy (EV tweeter) is better off with the zeners.
If you want some high power zeners for the Sound Dynamics you can use two NPN transistors. The Base-Emitter junction has a reverse breakdown (zener action) at 7V. You can use any inexpensive power device, metal or plastic (2N3055, TIP41, etc.). Note: this clamps at about twice the power that the EV tweeter can handle, but the Hepner style diapgragm will handle it.
Because of the lower crossover point on the Sound Dynamics I think I would prefer to use the lightbulb.
The zener protection works best on three-way speakers with their higher crossover points (Klipsch uses 6Khz/18dB).
Please explain how the deterioration occurs before the protection is active.
"They have great horn tweeters and they use the same diaphragms as Klipsch Heresy II's."
The 10W rated 211-2 will protect that tweeter very well.
The original Heresy (EV tweeter) is better off with the zeners.
If you want some high power zeners for the Sound Dynamics you can use two NPN transistors. The Base-Emitter junction has a reverse breakdown (zener action) at 7V. You can use any inexpensive power device, metal or plastic (2N3055, TIP41, etc.). Note: this clamps at about twice the power that the EV tweeter can handle, but the Hepner style diapgragm will handle it.
Because of the lower crossover point on the Sound Dynamics I think I would prefer to use the lightbulb.
The zener protection works best on three-way speakers with their higher crossover points (Klipsch uses 6Khz/18dB).
on old RCF event 3000 crossover uses halogen bulb at 24v i think 50w for compression tweeter, and on low volumes it sounds muddy,so i would avoid bulb at home use
Toni, you completely misunderstand what a resistor attenuator is capable of, if you blame the resistance of the halogen bulb for the "sounds muddy"
BTW,
a 50W 24V halogen bulb will have a cold resistance of about 1r and probably a bit less.
100mA passing through 1r for 10us will heat the filament by ?. Not much would be my guess.
100mA into an 8ohm 98dB/W@ 1m tweeter will give about 87dB @ 1m.
BTW,
a 50W 24V halogen bulb will have a cold resistance of about 1r and probably a bit less.
100mA passing through 1r for 10us will heat the filament by ?. Not much would be my guess.
100mA into an 8ohm 98dB/W@ 1m tweeter will give about 87dB @ 1m.
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wouldnt lower wattage bulbs make more difference than bigger ones?
i say muddy sound on low power , maybe around few watts i never said that bulb was lit , could you calculate dB@1m when same tweeter impedance is 9 ohms or at 90mA , or is difference too small? sry for confusion and thanks for answers
Hi toni,
I am sure you can do the calculations yourself.
R=U/I ; P=I^2*R; P=U*I ; I=current; R=resistance
X(dB)=10log(P2/P1); P=power
X(dB)=20log(U2/U1); U= voltage
I am sure you can do the calculations yourself.
R=U/I ; P=I^2*R; P=U*I ; I=current; R=resistance
X(dB)=10log(P2/P1); P=power
X(dB)=20log(U2/U1); U= voltage
No that´s actually the way you want them to work. At low average level they are cold and almost no effect. If they get warm they progressively limit the average power. They do not limit peaks because the thermal mass prevents them to react fast.
The problem with the zeners has been mentioned, they also limit harmless short term peaks, because they cannot see the difference between short harmless peaks and high average level, they just react to voltage. Bad sound.
Jan
no i cant. but i still wouldnt use damn bulbs in speakers at home.
would it be -0,3db differrence ? can it be heard on low power? i know this sounds like jibberish for you people with understanding in math but i dont know thats why i ask ,that log formulas sounds like chinease text for me 😕
would it be -0,3db differrence ? can it be heard on low power? i know this sounds like jibberish for you people with understanding in math but i dont know thats why i ask ,that log formulas sounds like chinease text for me 😕
The point I was making was that any series resistance in series with the tweeter will attenuate the tweeter level (and will progressively alter the crossover point for the tweeter as the resistance of the filament increases and decreases with temperature).
The resistance of a bulb can be several ohms when cold, depending on it's wattage. It may seem like a good, simple idea and would work somewhat at lower power levels but once high power is applied the heating of the filament will cause significant change in the tonal balance of the loudspeaker.
C.M
"Last time I looked Zener diodes were non linear parts."
Sure, when they are in their active state (which was my point).
By using two in series the capacitance of the junction (which will hold a non-linear charge on music) will not bleed off (so linearity is not an issue). This is also why there is a small diode in series with the zener when used as a gate clamp on FET outputs.
For those audio golden ear types (or anyone that thinks they are), just use a relay in parallel with the bulb. It is now out-of-circuit until it needs to be there.
EV made a device known as the STR tweeter protector, and had an application note of how to add the bulb in parallel with the relay contacts.
http://electrovoice.com/downloadfile.php?f=STR%20EDS.pdf
http://www.electrovoice.com/downloadfile.php?f=STR%20Service.pdf
They show up on eBay from time-to-time, but they are easy enough to make.
Sure, when they are in their active state (which was my point).
By using two in series the capacitance of the junction (which will hold a non-linear charge on music) will not bleed off (so linearity is not an issue). This is also why there is a small diode in series with the zener when used as a gate clamp on FET outputs.
For those audio golden ear types (or anyone that thinks they are), just use a relay in parallel with the bulb. It is now out-of-circuit until it needs to be there.
EV made a device known as the STR tweeter protector, and had an application note of how to add the bulb in parallel with the relay contacts.
http://electrovoice.com/downloadfile.php?f=STR%20EDS.pdf
http://www.electrovoice.com/downloadfile.php?f=STR%20Service.pdf
They show up on eBay from time-to-time, but they are easy enough to make.
Yes, it is quite audible. But it has been used commercially and it does save your tweeters.
And your ears too. 10W into a horn loaded compression driver is going to giving hearing damage levels
"but once high power is applied the heating of the filament will cause significant change in the tonal balance of the loudspeaker."
True, and the clipping will make it quite a bit brighter as well.
The lightbulb actally can make it sound more balanced during clipping.
It was a good fix for Klipsch KG4's in the mid 80's that were burning out diaphragms left and right. I tried the 561 that Boston Acoustics used in their C700 speakers, it worked quite well. The 211-2 is a 561 with end caps you can solder to (the 561 steel leads are not solder friendly, Boston spot-welded a tinned copper lead onto their 561 bulbs).
The JBL SK3 bulbs have the same spec as the 1156, just a different glass package. The SK3/1156 is best suited for 44mm~50mm coils.
True, and the clipping will make it quite a bit brighter as well.
The lightbulb actally can make it sound more balanced during clipping.
It was a good fix for Klipsch KG4's in the mid 80's that were burning out diaphragms left and right. I tried the 561 that Boston Acoustics used in their C700 speakers, it worked quite well. The 211-2 is a 561 with end caps you can solder to (the 561 steel leads are not solder friendly, Boston spot-welded a tinned copper lead onto their 561 bulbs).
The JBL SK3 bulbs have the same spec as the 1156, just a different glass package. The SK3/1156 is best suited for 44mm~50mm coils.
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