Eminence Crossovers incorperate "aviation light bulbs" for current protection. I like the old-school idea unfortunetly I live in the UK and buying from Eminence is problematic. There must be other sources. In any case they are not magic. How do I know if the bulbs are correct for my speaker?
I'm thinking that pushing 500W through a 4 ohm driver using P= I²R gives me a current of 11.2A and then V=IR gives me a 45V
Armed with that information, how/where can I go shopping?
I'm thinking that pushing 500W through a 4 ohm driver using P= I²R gives me a current of 11.2A and then V=IR gives me a 45V
Armed with that information, how/where can I go shopping?
Going to be sad if someone breaks or burns out a bulb and replaces it with a LED equivalent.
I know some speakers have used the common 1157 style bulb. Wondering if someone one day will have to make a trip to a junkyard to get replacement bulbs for the speaker.
I know some speakers have used the common 1157 style bulb. Wondering if someone one day will have to make a trip to a junkyard to get replacement bulbs for the speaker.
Usually these are about 25 watt (12v x 2A) and therefore for HF only. You can paralllell connect two to get higher power handling like Eminence do in their stock crossovers. Be aware that you lose a dB sensitivity. They’re not meant to put on the amp side of the crossover to protect the whole speaker nor on the bass driver but after high pass for treble protection. They start to blink when you play loud and get hot before they break. They also compress the source reducing peak loads and mechanical damage (again only meant for HF drivers).
Fuse Type Lamps
Speaker Crossover Tweeter Protector Lamp
Eminence PX:BULB Replacement Tweeter Protection Lamp for Crossover
Fuse Type Lamps
Speaker Crossover Tweeter Protector Lamp
Eminence PX:BULB Replacement Tweeter Protection Lamp for Crossover
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That sounds like the old Motown trick. They used to compress the 3K region to make the lead vocal sit above the track. Maybe its a good thing - while not being in any way accurate.
They compress only peaks at loud levels which is a good thing both for the tweeter and your ears, lot of people like that sound too as it smoothens things but yes it’s reducing dynamics so it’s less true to the source. In PA many times active line level compressors are used as well to protect the whole system (speaker and amps) and will have the same impact to the sound reducing the loudest peaks. Back to the bulbs I think when you parallel connect two the power handling increase but the compression decrease as well meaning less protection which fits more powerful tweeters, that’s what eminence do, their crossovers are build for high power but you can replace the double bulb with a single one if you have a 30 watt tweeter, as said that will have a little more impact on the sound with more compression. Im not sure how many ohms these are at low levels but at higher levels the ohm increase so the cut off frequency also increase (again only during peaks at loud levels) which also protects the driver more. When it blinks you know you should turn it down.
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500W through a filtered tweeter is wildly wrong! It doesn't work like that at all! 😀
The "Fuse" (more correctly "current limiter") is designed to stop microphone feedback howl destroying the tweeters in PA situations.
Broadly speaking, resistance of metal increases 1% for every 2.5C temperature rise.
Eminence "fuse" bulbs for eminence compression driver crossovers are available at Blue Aran near Swaythling on the outskirts of Southampton.
PXB2:2K5CX - Crossovers | Eminence Speaker
Real Pro-Audio specialists and pleasant people to boot:
Eminence : Eminence PX Bulb :: PS6.11 IN STOCK (4 Sep 2021)
The "Fuse" (more correctly "current limiter") is designed to stop microphone feedback howl destroying the tweeters in PA situations.
Broadly speaking, resistance of metal increases 1% for every 2.5C temperature rise.
Eminence "fuse" bulbs for eminence compression driver crossovers are available at Blue Aran near Swaythling on the outskirts of Southampton.
PXB2:2K5CX - Crossovers | Eminence Speaker
Real Pro-Audio specialists and pleasant people to boot:
Eminence : Eminence PX Bulb :: PS6.11 IN STOCK (4 Sep 2021)
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What are they actually protecting?
If full cabinet (not common but have seen a couple examples) then your Math applies and they must be HUGE.
500W bulbs, and all that dissipated heat must go somewhere.
But they probably only protect the HF drivers, a much lighter task.
Typical is car light type ones , as mentioned above 12V 1 or 2A rating, sometimes 24V ones.
FWIW typical Aviation bulbs run on 28V so that may also be a possibility.
But I have a beef with your question, you ask:
If full cabinet (not common but have seen a couple examples) then your Math applies and they must be HUGE.
500W bulbs, and all that dissipated heat must go somewhere.
But they probably only protect the HF drivers, a much lighter task.
Typical is car light type ones , as mentioned above 12V 1 or 2A rating, sometimes 24V ones.
FWIW typical Aviation bulbs run on 28V so that may also be a possibility.
But I have a beef with your question, you ask:
but you do NOT show a picture of them, nor dimensions, shape, terminals or any labels printed on them, are we supposed to GUESS out of the blue?
I think his question is for the Eminence types.
They are 12,8V 2,1A to my knowledge so about 25-30watt.
Two in parallel suites for 60 watt or higher compression drivers.
It’s indicating a 3:1 compression but I guess that’s at its limit only.
I’ve also seen 20watt 12v halogen being used in home hifi with external crossover. I have no idea what’s the compression rate and impedance curve look like for halogen. Watch out for fire.
They are 12,8V 2,1A to my knowledge so about 25-30watt.
Two in parallel suites for 60 watt or higher compression drivers.
It’s indicating a 3:1 compression but I guess that’s at its limit only.
I’ve also seen 20watt 12v halogen being used in home hifi with external crossover. I have no idea what’s the compression rate and impedance curve look like for halogen. Watch out for fire.
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The catch is the bulbs will only really start compressing with too much sustained power.
They will also run away and keep limiting until there is less power.
Not so much a problem for real music. Might be a problem for highly compressed modern music though.
They will also run away and keep limiting until there is less power.
Not so much a problem for real music. Might be a problem for highly compressed modern music though.