How long is the average Pa/disco speaker life

[MrSpeedy]

Hi guys,

 

just pondering, I have 4 Celestion FTR15 4080F drivers used in a mobile disco, but that isnt the point.

 

What would be the life of these speakers, before recone or replacement ??

And what the average life of a PA driver?

 

I suppose it hinges on how hard they are used so lets say used all their life at 3/4 volume and once or twice full volume for an hour or two.

 

 

could make an interesting thread :)

 

Thanks guys

 

Toby

[TonyMitchell]

Hi guys,

 

just pondering, I have 4 Celestion FTR15 4080F drivers used in a mobile disco, but that isnt the point.

 

What would be the life of these speakers, before recone or replacement ??

And what the average life of a PA driver?

 

 

How long's a piece of string?

 

There is no "average life" of a driver per se, however the words "mobile disco" make me suspect the life may be closer to half that of a goldfish, than a tortoise.

 

We have PA boxes on our inventory with original drivers well over 15 years old.

 

We also have mobile DJs that come to us every 8 months for a new pair of speakers, because they have blown theirs.

[Wilflet]

I suppose it hinges on how hard they are used so lets say used all their life at 3/4 volume and once or twice full volume for an hour or two.

 

 

 

Toby

 

and also how they're stored, how there treated in general, and is that 3/4 volume as in dynamic program material with peaks up to 3/4 or is it overly compressed square waves at a constant 3/4 volume.

[Bobbsy]

....and how they're built in the first place. Something from D&B, Meyer or l'Acoustics is likely to last rather longer than anything in the Maplins "ProSound" range even if they're all treated well.

 

Bob

[sleah]

and also how they're stored, how there treated in general, and is that 3/4 volume as in dynamic program material with peaks up to 3/4 or is it overly compressed square waves at a constant 3/4 volume.

 

Storage can make quite a difference. I mentioned in another thread I have some 'rolled edge' type drivers that were attacked by moisture and tore. Nothing to do with how they were driven. I have actually managed to repair them by replacing the foam surround and they are as good as the day they came from the factory again, which was over 10 years ago.

To put the quote above in plain english :P :( speakers will die rather sooner than you would like if they are fed with a distorted signal, such as a DJ driving his mixer in to red all the time :)

So providing they have a good environment both in storage and in use, and they are fed a nice clean signal they may well outlive what ever business they are being used for ;)

[Rob_Beech]

Speakers will always die sooner than you would like. By default :)

[revbobuk]

This, or something like it, is said frequently on this forum. But I would like to know why. Obviously, a square wave has a higher mean:peak ratio than a sine wave. But why would a speaker care whether a noise it is called upon to reproduce is distorted because the input stage of a power amp is clipping, or Jimi Hendrix is playing a distorted guitar, or a synth has picked a square wave patch?

 

Surely if the drive to a speaker is of appropriate bandwidth (no DC or LF for a mid-range drive unit, and no excessive HF energy being supplied etc) and the mean and instantaneous power is within spec, then the speaker won't care what the signal is? What is it about an overdriven DJ mixer that makes it any worse than Limp Bizkit?

 

Just curious...

 

I suppose it hinges on how hard they are used so lets say used all their life at 3/4 volume and once or twice full volume for an hour or two.

 

 

 

Toby

 

and also how they're stored, how there treated in general, and is that 3/4 volume as in dynamic program material with peaks up to 3/4 or is it overly compressed square waves at a constant 3/4 volume.

[Starstruck]

Also depends on what amp you are using . From the fact you say "Full volume" it sounds like you are using a lower powered amp which if you run at full volume you stand a high risk of clipping , which basically sends a DC voltage to your speaker, heats the coils and burns them out !

 

I would normally install a higher powered amp and only EVER run it at half volume .

 

I used to work in all the local night clubs and they only ever blew speakers with certain DJ's , the ones that had no understanding of a VU meter . They used to run the mixer hard into the red !! so even when the volume levels were low they were clipping the signal at the mixer , the amps boosted it and bang went the speakers.

 

So just like all the other guys have said how long is a piece of string. Depends on many many variables but they are all controllable by you . You have your finger on the volume and you control how your mixer is set.

 

Kev :-)

[sleah]

Going off slightly.... to me that Formula Sound limiter that goes between mixer and amps is the Holg Grail ('cos I can't afford one :( ).

At least once set correctly it will help protect speakers from damage by overdriving, even with a square wave (to a point :) ) by stopping the cone literally being thrashed to within a millimeter of it's life - only metophorically ;)

[paulears]

I've removed some 10" and 15" cabinets that date back to 1975 and they are as new. I have a pair of Shure Vocalmaster columns that still sound ok despite being 'vintage' now.

 

I'm not really sure of the point of this topic? If drivers are stored in damp conditions, then paper cones don't wear well at all. If the coils are overdriven, that kills them too. Rubber surrounds might suffer from age and lose elasticity which will impact on sound.

 

I'd hazard a guess that most cheap PA speakers get killed off early by their owners and never reach their actual normal use age limit by a very long way!

[sleah]

I've removed some 10" and 15" cabinets that date back to 1975 and they are as new. I have a pair of Shure Vocalmaster columns that still sound ok despite being 'vintage' now.

 

I'm not really sure of the point of this topic? If drivers are stored in damp conditions, then paper cones don't wear well at all. If the coils are overdriven, that kills them too. Rubber surrounds might suffer from age and lose elasticity which will impact on sound.

 

I'd hazard a guess that most cheap PA speakers get killed off early by their owners and never reach their actual normal use age limit by a very long way!

I don't think you could have aligned that hammer much squarer on the nail head if you'd tried!

 

My very limited experience agrees 100% with all of the above :)

[aidso]

does any one remember stage system 200s from EV? look at just how many of these are still in use today with all their orginal parts. Its all back to how long is a piece of string and the speakers will always go before you want them to and at the worst times aswell.

[MrSpeedy]

Well thats very interesting,

 

(Obviously taking into account storage and ensuring no moisture is received by the drivers etc.)

 

 

 

 

And everything always runs out quicker than you would like :blink: As said, default.

[Jivemaster]

Modes of failure in disco (ish) speakers

 

Tweeter - too much top usually meaning driven to distortion

Bass driver - too much bass or too loud kills the coil, too damp in store kills the cone or suspension

intermal crossover - dies on overheating due to over power.

 

Cabinet gets kicked, and softened by dampness in store, also gets used as a drinks tray. Usually gets scruffy beyond reuse before failure.

 

Handles and top hats fail due to ill treatment.

 

Mostly it's up to you to look afer them! If they sound sweet in use then they will usually sound sweet next time -for years. If they sound stressed then they are dying.

 

Several cheaper disco speakers have a very inflated opinion of their own handling capacity. read carefully! Assume that the given rating is a gross overestimate until you prove otherwise. I saw one range of speakers that had 400 emblazoned on the front, but the instruction book said 70w continuous and gave the 400w rating as a instantanious peak rating.

 

Some cheaper disco speakers handle the power but as heat not sound look at the sound level peak, and per watt.

[Tomo]

This, or something like it, is said frequently on this forum. But I would like to know why. Obviously, a square wave has a higher mean:peak ratio than a sine wave. But why would a speaker care whether a noise it is called upon to reproduce is distorted because the input stage of a power amp is clipping, or Jimi Hendrix is playing a distorted guitar, or a synth has picked a square wave patch?

There are many reasons.

 

The difference between a step-function and a continuous wave.

 

There is almost certainly a DC component when you're outside of the design range of amplification, because it's a very safe bet that at least one of the following holds true of your amp and preamps:

The high-side and low-side MOSFETs are not always perfectly matched.

The output curve of single-sided amplifiers is not a linear function once you're out of the design region.

The 'zero output' point is not exactly halfway between positive and negative rails.

The 'Positive maximum' is not the same as the 'negative maximum' output.

 

Thus, when you clip, there will be a DC component due to the mismatch between the positive-going and negative-going

 

The cheaper the amplifier (remember there's an amp in your mixer), the more likely this is.

 

And the Jimi Hendrix distortion is from a tube, not a MOSFET. Tubes distort quite softly, MOSFETs clip very hard.

- MOSFETs 'suddenly' enter the full-conduction region, while tubes 'fade' into saturation.

 

Many people like tube distortion, but nobody likes clipping.