passive v active speakers for FOH

[Sam Spoons]

Take the RMS power handling in watts of the speakers, (i.e. continuous not peak) and divide that number by 10 to guesstimate the power going to the tweeter. Measure the resistance of the tweeter drivers (probably about 6 ohms for a nominal 8 ohm speaker) and use ohms law to calculate the current needed for max power. Fit the next value down of polyfuse and see how you go. That rating should be on the safe side, it's a bit suck it and see I know but polyfuses are cheap so if that proves to mute the tweeters at a much lower level than you know they can handle it's easy enough to fit higher rated ones.

Hopefully somebody with better theoretical knowledge than me will be along to correct me if I'm wrong but that's pretty much how I did mine, they seemed to work ok and I didn't blow any tweeters.

[Wonks]

There's probably a power rating or a product ID number on the tweeter which you should be able to look up to give you its power handling. I'd probably go just below the rating given as it will probably be rather optimistic.

Alternatively it may be possible to fit a compression driver with a greater power handling capacity.

[manleyelop]

There's probably a power rating or a product ID number on the tweeter which you should be able to look up to give you its power handling. I'd probably go just below the rating given as it will probably be rather optimistic.

Alternatively it may be possible to fit a compression driver with a greater power handling capacity.

OK cheers I'll mention that to the tech guy the yamaha speakers I have never seem to have the same issue could that be due to there internal speaker protection?

[Wonks]

Either that or the driver has a higher rating, say 50W instead of 30W.

HF distortion is supposed to be the killer of tweeters, so there may be some distortion somewhere in the system that is getting through. The P7000 is correctly rated for the speakers, so it shouldn't be the amp distorting. There might possibly be a mixer problem, so it might be worth having a look at the output of that with a scope. Otherwise maybe fit a non-adjustable limiter between the mixer and amp to stop the signal getting too hot.

[Sam Spoons]

The problem is that wherever the distortion originates it will get through to the speakers, a limiter will limit the peak level but not the average level and it's the average level that destroys tweeters. As Wonky says, if the tweeters are underrated they will be, effectively, more fragile but if heavy distortion is causing the problem (and I suspect it is due to some clients not respecting the gear) it's possible neither will help.

I can't find a schematic for the Yamaha crossover but did find a pic and there is a component open the circuit board labelled CL1 which is either a ceramic disc capacitor or a polyfuse (you mention the manual says "Overload protection is also included to protect the S115V's components." which would suggest the latter). Also the Yamaha's have 2" tweeter drivers which are usually rather more robust than the 1" in most budget speakers.

Gotta go out now, Gypsy Jazz session

[manleyelop]

The problem is that wherever the distortion originates it will get through to the speakers, a limiter will limit the peak level but not the average level and it's the average level that destroys tweeters. As Wonky says, if the tweeters are underrated they will be, effectively, more fragile but if heavy distortion is causing the problem (and I suspect it is due to some clients not respecting the gear) it's possible neither will help.

I can't find a schematic for the Yamaha crossover but did find a pic and there is a component open the circuit board labelled CL1 which is either a ceramic disc capacitor or a polyfuse (you mention the manual says "Overload protection is also included to protect the S115V's components." which would suggest the latter). Also the Yamaha's have 2" tweeter drivers which are usually rather more robust than the 1" in most budget speakers.

Gotta go out now, Gypsy Jazz session

The desk I'm using is pretty old it's an old spirit studio but I had it serviced not too long ago but as I mentioned the yamaha speakers don't seem to have any tweeter issues but the Ld Speakers do I'm starting to go off them now lol Enjoy your night out

[Wonks]

Then I'd find some more Yamahas and ditch the LDs.

[manleyelop]

Then I'd find some more Yamahas and ditch the LDs.

Funny you should say that I bought a pair of yamaha speakers yesterday not got them yet now if they blow something else is going on but I'm hoping that won't happen

[Sam Spoons]

Sounds like a Plan, hope it works out.

And thanks the Gypsy Jazz session went well.

[James Perrett]

A quick calculation says that 30W into 8 ohms requires a current of just under 2A. I'd probably be looking at something like

https://cpc.farnell.com/littelfuse/60r0 ... t=polyfuse

as you want it to trip fairly quickly if the current goes too high (that one should take around 3 seconds at 2A).

[manleyelop]

Sounds like a Plan, hope it works out.

And thanks the Gypsy Jazz session went well.

I had to bite the bullet & try some other speakers so went for some Yamaha C115 v a slightly cheaper option but fingers crossed they will be OK if not then plan C

I do Rock & blues which is easy when your speakers keep getting blown

[manleyelop]

A quick calculation says that 30W into 8 ohms requires a current of just under 2A. I'd probably be looking at something like

https://cpc.farnell.com/littelfuse/60r0 ... t=polyfuse

as you want it to trip fairly quickly if the current goes too high (that one should take around 3 seconds at 2A).

Thanks for the info & link so you reckon that polyfuse would do the job protecting the LD Stinger 15 they are an 8ohm speaker if so i'll pass that onto the tech here & get them fitted & thanks for the help everyone much appreciated!

[DanR]

Poly fuse is a good idea.
I have a Behringer Pro-XL MDX2600 compressor/limiter installed on my Yamaha P7000/EV SX300 PA.
One of these would protect the HF drivers on your speakers.

[manleyelop]

Poly fuse is a good idea.
I have a Behringer Pro-XL MDX2600 compressor/limiter installed on my Yamaha P7000/EV SX300 PA.
One of these would protect the HF drivers on your speakers.

Good idea i have a dbx limiter so ive used that with these Yamaha C115V

[James Perrett]

so you reckon that polyfuse would do the job protecting the LD Stinger 15

Just had a quick look at the spec for those speakers and they are supposed to already incorporate protection so it would be worth having your tech check that whatever is fitted is actually working. If they already use a polyfuse then it may be worth trying a lower value and making sure that it is a 60V type rather than a 30V type. If I was your tech I'd start with a polyfuse with a fairly low current rating just to be on the safe side and maybe fit a bigger one if it was tripping too often.

[manleyelop]

so you reckon that polyfuse would do the job protecting the LD Stinger 15

Just had a quick look at the spec for those speakers and they are supposed to already incorporate protection so it would be worth having your tech check that whatever is fitted is actually working. If they already use a polyfuse then it may be worth trying a lower value and making sure that it is a 60V type rather than a 30V type. If I was your tech I'd start with a polyfuse with a fairly low current rating just to be on the safe side and maybe fit a bigger one if it was tripping too often.

Ok thanks i wonder if the passive LD stingers i have don't have protection as there pretty old hmm im not quite sure which model they actually are would be interesting to find out what's going on with them i think the speakers are LD Systems LDEB 152A Stinger

LDEB152 15“/1“ passive LD/Eminence & BMS Loudspeaker, 500 W RMS, 103 dB
Multi functional high quality loudspeaker with Eminence 15“ speaker and BMS 1“ compression driver.

18 mm plywood cabinet structure, highly durable textured lacquer finish, SM707 adjustable angle speaker stand receptacle with a variable vertical angle that adjusts in 4° increments to +/-18°.

Specifications

Article No.: LDEB152A

Nominal Impedance: 8 Ω

Rated power capacity RMS 500 W

Amplifier Module: B&O ICEpower 1000 ASP

Max. SPL: 130 dB

Frequency range (-10 dB): 45 Hz –18 kHz

Crossover frequency: 1.5 kHz

Connections: Mic/Line Input, Volume Control, LF+HF EQ, External Speaker Output

Cabinet style: 18 mm Multiplex plywood

Dimensions (W x H x D) 499 mm x 650 mm x 438 mm

Weight: 30,5 kg

[manleyelop]

Hmm im not sure it's the same speaker but they look the same

[Wonks]

That spec is for an active version.

[manleyelop]

That spec is for an active version.

yes wrong speaker i see it now mention the amplifier i know mine are old but i can't remember what model they are

They are pretty old though

can i upload pics here?

[Sam Spoons]

130dB SPL is reasonably impressive and 3dB more than to the current version. I suspect they don't have any tweeter protection but they do have 1" tweeter drivers which are less robust that 2" units in your Yamahas. If you have already bought some more Yamahas then you are, hopefully, sorted. If you still want to install some protection then polyfuses will probably be a good call.

[manleyelop]

130dB SPL is reasonably impressive and 3dB more than to the current version. I suspect they don't have any tweeter protection but they do have 1" tweeter drivers which are less robust that 2" units in your Yamahas. If you have already bought some more Yamahas then you are, hopefully, sorted. If you still want to install some protection then polyfuses will probably be a good call.

Ive bought the yamaha's & started using them ive also put a dbx 1046 limiter on the master outputs

Im hoping to use the LD in another room that is smaller if i can sort the issue out with them if not themim going to sell them