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SWR Big Ben

chris4001asat

chris4001asat

Reverend Guitars Production Manager
Commercial User
Dec 16, 2002
1,012
300
57
Toledo, Ohio
www.polkafloyd.com
Disclosures
Warehouse Manager : Reverend Guitars
#1
So I made my first purchase off ebay....Bet you know where this stories going!...An SWR Big Ben, powered by my Super Redhead. After 4 or five rehearsals, it fries out. Do you think I was underpowering it maybe? Or did I just buy an abused cabinet?...It's definitely an older model, has a Bag End driver in it. Any opinions?
 
#5
If you drive a solidstate amp to clipping, it distorts with square waves. Speakers don't like square waves.
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More accurately clipping refers to the signal peaks being chopped off because they have reached the amplifier 'rails'. A square wave is different. This pertains to any type of amp its just that the characteristic of ss clipping is different from tube amp clipping. Speakers can dissipate a certain amount of power for a certain period of time before the voice coil is damaged. Clipped signals dont mean that the speaker is at max capacity. If you have a speaker rated at 500 watts and you feed a clipped signal from a 10 watt amp into it you will not damage the speaker but you will damage the amp sooner than later. You cannot underpower a speaker.
 
#7
OK.......if you drive an amp to clipping, the resulting wave will have more effective power than the amps rated output. This is because the waveform will have flat, squared off tops and bottoms, and the speaker cannot physically follow that signal. When the signal squares off, the speaker cones inertia will cause it to continue in the direction it was going for a bit - it can't stop it's motion on a dime. It's like accelerating a car at full throttle for 100 feet and then trying to stop it in one inch.

So, if an amplifier is rated to put out 300 watts at .5% distortion, when you drive it to 5% distortion the speaker effectively sees a lot more than that.

You probably won't fry the voice coil this way, but you certainly can push the speaker past it's mechanical limits if the amp is rated to put out anything near the speakers limit. Whether you cook the voice coil with excessive wattage or damage it mechanically, it's still a blown speaker.

So, no, you can't kill a 400 watt speaker with a 10 watt amp, but you certainly could with a 300 watt amp, maybe a 200.
 
#8
You are correct BruceWayne! I see youve done your reading. This is not a case of underpowering a speaker however. What you have described is overdriving an amp and subsequently damaging a speaker due to excessive excursion. This is actually OVERpowering the speaker. A speaker will crease or tear under those conditions and its not because it cant stop fast enough its because it has been pushed past its limit. Its more analagous to pulling a spring past the point of permanent deformation. A speaker acts very much like a spring.

Unfortunalely neither one of us has provided any information about what may be wrong with this gentlemans Big Ben speaker.

Chris: check the speaker for damage! If its creased I would think a replacement wouldnt be too terribly expensive. Best of luck... :hmm:

You cannot underpower a speaker.
 
#9
Originally posted by metron

Unfortunalely neither one of us has provided any information about what may be wrong with this gentlemans Big Ben speaker.
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:D Yeah, I suppose we got a bit off on a tangent..........

Anyway, the Super Redhead is rated 350W @ 4 ohms, 400W @ 2.67 (using an 8 ohm extension), and the Big Ben 400w @ 8 ohms, so you really couldn't fry the voice coil and it'd be pretty hard to cause mechanical damage.

BUT, you also said it's got a Bag End speaker in it. It sounds like it's been replaced - as far as I know, SWR doesn't use BE speakers. So it could be that

1) That speaker may only be rated for 200 watts - as are a lot of Bag End's speakers. And

2)The speaker is in a cabinet that is larger than the speaker is designed for - most of BE's cabs are pretty small. And the cabinet tuning could be all wrong for that speaker as well. When it comes to bass cabs, you cannot just put any speaker that fills the hole in a cabinet. There's a lot of considerations. Putting a speaker in a mis-tuned, oversize cabinet makes it very easy to blow it.

And anyway, when you say "it's fried", what do you mean? No sound at all?
 
#10
Actually there were several SWR enclosures that used Bag End drivers, the Bigfoot 2x12 and the Big Ben were two such models, if I remember correctly. You should be able to get a replacement directly from Bag End, rather than going through SWR for a new driver. Fender's recent buyout of SWR has meant long waits for parts because Fender doesn't have adequate parts stock yet. I know this from experience because I recently needed some parts for my SM900 and was told a 60-90 day wait was likely.
Hope this helps,
Rod
 
#11
as far as I know, SWR doesn't use BE speakers
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My 1999 and 2000 Catalogs show that the Big Ben did indeed use an 18" Bag End woofer. The 10 inch in the Triad was also a Bag End. I do not know why Fender/SWR has discontinued using Bag End products.

If the cone and suround do not look damaged I would open up the cabinet and first check the electrical connections. If something came loose, it would not produce sound. Check the jack and the connections to the speakers. After that, check the physical aspects of the speaker coil and spider. If anything looks funny, it is probably time for a replacement.

I just received a "broken" cab that was simply a loose connection between the jack and the speaker itself.

-Aladdin
 
#12
Whew! So many questions to answer! Thanks for all the suggestions and opinions. You guys are great! I don't know if this matters at all, but it seemed like the 18 never had a lot of volume to it. The 10s in the Redhead have an on/off switch for them. Just seems when I would flip that switch, there was a HUGE volume difference.
By fried, I mean crackly sounding, to no sound at all. I was thinking a bad connection at first, so I pulled the speaker out and checked, but it looked ok. That's when the drummer said ( I know, never listen to the drummer!) look at how it's moving when I push on it. When he pushed on one side, just that side would go down, not the whole thing. I couldn't see any tearing or creasing on the speaker either. I did email BE, I can get a replacement for $140. He also said that the 18 was the only SWR speaker that they have available anymore.
 
#15
Originally posted by chris4001asat
Ok, My logic has always thought this, but I never could think of a logical reason. Why shouldn't you push, and by that, I mean slight pressure, down on a speaker?
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Pushing down on both sides of a speaker so that it moves in a linear motion is fine, but I wouldn't make a habit of it. The only reason to do this is to check for any rubbing between the voice coil and the magnet if you suspect a blown speaker, but always push evenly and gently on both sides so that it goes straight in and out. Pushing on only one side of it can stretch the spider unevenly. A spider is kind of like a small, second speaker cone inside the speaker that keeps the voice coil properly aligned in the magnet's gap. If you make the voice coil sit a little crooked, at the very least the speaker is not going to perform very well because the force that the magnet exerts on the voice coil won't be consistent, and at worst it's actually going to start rubbing on the sides of the gap. There's not very much room in there for the voice coil, just a few millimeters, and if it isn't moving perfectly straight in the gap, you've got problems. Your best bet for having a speaker perform well and live long is to keep hands off of it. It's not what they're built for, so the best thing is to keep them safely behind a good, sturdy grille.

I know there's a strange urge in all humans to push on speakers, but ya really gotta fight it. There's just no good reason to do it, and a lot of reasons not to.
 
#16
The Big Ben is always going to sound a bit quieter than the 210's in the Redhead beacause:

a) the 10's are more efficient so at any given volume they produce more sound

and

b) they have a stronger midrange emphasis which makes then sound louder to our ears.

IMO, the Big Ben is bestas a great but quiet standalone cab or as part of a rig where it has its own poweramp and volume control.
YMMV.
 

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