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Author Topic: Protecting speakers from nutters  (Read 5601 times)

Sangram Rakshit

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Protecting speakers from nutters
« on: November 15, 2010, 07:31:41 am »

We do a few home setups and there is one particular setup I need help with. We had installed (as in not me, the company I'm working with now) four Waterfall speakers in a nice living room, powered by a Sunfire 300W/ch amplifier. Speakers are connected in a 4-channel stereo matrix and electrically in parallel, well within the amplifier's capabilities.

However, there is a consistent problem with the speakers blowing. So far the speakers have been recoiled a few times, and in my first visit to the site on Saturday I realised that all 4 speakers are measuring open circuit at the terminal, and none of the drivers are as much as emitting a single squeak. The wiring to the speakers is fine as is the amplifier, we placed a test speaker and it works without any issues.

The speakers are to be opened and repaired by my service tech over the next few days, we're getting the replacement drivers from Waterfall wherever applicable. However, the long-term problem of insane power being applied by irresponsible users remain.

I was thinking of applying a 100 watt lightbulb covered in black craft paper in series with the amplifier output, to protect the speakers from overcurrent. We also thought of resistors, but that would reduce the overall output volume even at low levels - which might be prominently noticed and spur even more energetic application of volume, endangering the resistors as well as the speakers.

Would welcome any more ideas and suggestions. Would like to stay away from adding any more visible equipment if possible.

TIA

Sangram
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Silas Pradetto

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Re: Protecting speakers from nutters
« Reply #1 on: November 15, 2010, 08:06:01 am »

How about this revolutionary idea: Get speakers that are capable of handling the power, or more importantly, that satisfy the client's desire for volume?

Trying to band-aid the current setup is only asking for more trouble.
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Mac Kerr

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Live Audio forums
« Reply #2 on: November 15, 2010, 11:10:26 am »

As this topic has nothing to do with live audio it is being moved to the more appropriate install forum.
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Charlotte Evans

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Re: Live Audio forums
« Reply #3 on: November 15, 2010, 12:34:47 pm »

I've just had a look at the Waterfall website and I don't know which model you have installed but even the beefiest item in the Waterfall range recommends a top amplifier rating of 250w ....so I'd guess that the Sunfire is just cooking 'em when the "welly" is applied.  Confused
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Jason Lavoie

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Re: Protecting speakers from nutters
« Reply #4 on: November 15, 2010, 09:55:46 pm »

is the customer paying the bill?
is he complaining, or is he one of those people who considers blown speakers to be a sign of a good party? maybe he goes to work and brags about how much he has to pay to fix is stereo..

have you asked him if he'd like some bigger speakers?

Jason
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Sangram Rakshit

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Re: Protecting speakers from nutters
« Reply #5 on: November 15, 2010, 11:30:46 pm »

Thanks for the replies. Sorry about posting in the wrong forum, won't happen again.

@silas - the setup is over two years old and it's highly unlikely the client will plump for a new purchase. To put it into perspective, we haven't been fully paid for the original contract and the client has not opted for a maintenance contract either. Not because they don't have the money, but because they're penny-pinching. Due to certain other influences we are unable to push them aggressively for payment or anything else.

@Charlotte -  that is exactly what is happening. The Waterfalls are not built to take an aggressive amount of power, they're architectural speakers. They are installed in a very formal living area so I guess the original installer had no idea that they would be trying to rock out. There is an actual dance floor with appropriate equipment installed, it's just that they party close to the bar where this setup is.

@Jason: The customer will 'pay' for a reasonable amount of work. They are whining incessantly about the setup, it's over two years old and obviously issues keep cropping up due to careless and aggressive handling. They are also extremely unpleasant to deal with - we really have no choice but to service their needs because a very large chunk of our corporate contracting is tied to the commercial area they own and rent out to large companies.

And, they don't 'go' to work. They don't need to Smile

I am pretty sure the client will want to retain the architectural look of the Waterfalls. The question is how to fix the consistent blowing issue, and I thought of the lightbulbs. I also thought of reducing the output level on the preamp (it's a NAD pre with a variable pad on one of the outputs, I can cut up to 6dB). Maybe both, but I don't want to have him crank it up even more. Or maybe a smaller amplifier for the room.
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Jordan Wolf

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Re: Protecting speakers from nutters
« Reply #6 on: November 16, 2010, 12:18:25 am »

Have you considered putting one of these in the rack?
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Sangram Rakshit

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Re: Protecting speakers from nutters
« Reply #7 on: November 16, 2010, 12:28:10 am »

Wow, thanks for that. I'll look at a way of slipping it in, seems exactly what we need Smile

I assume it will work with XLR/RCA dapaters? My system is unbalanced.
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Charlotte Evans

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Re: Protecting speakers from nutters
« Reply #8 on: November 17, 2010, 06:46:56 am »

Sangram Rakshit wrote on Tue, 16 November 2010 05:28


I assume it will work with XLR/RCA dapaters? My system is unbalanced.

Yes it will but if pin 2 is hot you will need to link pin 3 to pin 1 on the XLR adaptor lead.
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Ivan Beaver

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Re: Protecting speakers from nutters-Payments?
« Reply #9 on: November 17, 2010, 08:47:24 pm »

Sangram Rakshit wrote on Mon, 15 November 2010 23:30

Thanks for the replies. Sorry about posting in the wrong forum, won't happen again.

@silas - the setup is over two years old and it's highly unlikely the client will plump for a new purchase. To put it into perspective, we haven't been fully paid for the original contract and the client has not opted for a maintenance contract either. Not because they don't have the money, but because they're penny-pinching. Due to certain other influences we are unable to push them aggressively for payment or anything else.

@Charlotte -  that is exactly what is happening. The Waterfalls are not built to take an aggressive amount of power, they're architectural speakers. They are installed in a very formal living area so I guess the original installer had no idea that they would be trying to rock out. There is an actual dance floor with appropriate equipment installed, it's just that they party close to the bar where this setup is.

@Jason: The customer will 'pay' for a reasonable amount of work. They are whining incessantly about the setup, it's over two years old and obviously issues keep cropping up due to careless and aggressive handling. They are also extremely unpleasant to deal with - we really have no choice but to service their needs because a very large chunk of our corporate contracting is tied to the commercial area they own and rent out to large companies.

And, they don't 'go' to work. They don't need to Smile

I am pretty sure the client will want to retain the architectural look of the Waterfalls. The question is how to fix the consistent blowing issue, and I thought of the lightbulbs. I also thought of reducing the output level on the preamp (it's a NAD pre with a variable pad on one of the outputs, I can cut up to 6dB). Maybe both, but I don't want to have him crank it up even more. Or maybe a smaller amplifier for the room.

If the customer hasn't paid for the work that has already been done-then why are you still working for them?

SO you say they won't pay past bills-but "will" pay future bills Rolling Eyes   How do you know?

If you simply reduce the gain of the system-then they will complain that it doesn't get as loud as it used to-and you damaged it during your repair-so they won't pay you-AGAIN.

Either they need a more powerfull system-and are willing to pay for it-or they have to learn to keep the level down-or else pay all their bills and then you glady keep repairing the speakers everytime they tear them up.

There is no simple "band aide" you can put on the system.

As has been said-you need more rig for the gig. Simple as that.  OR just keep spending money on repairs.
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Sangram Rakshit

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Re: Protecting speakers from nutters-Payments?
« Reply #10 on: November 18, 2010, 12:54:57 am »

@Charlotte: Thanks - This would be fine on the input, but if Pin 1 is a floating cold pin would that not cause undesired operation?

I have a E-mu 1212m with a fully balanced output, and grounding the cold end really makes it sound terrible if the amplifier is unbalanced, so I run it with pin 1 floating instead.

@Ivan - we have certain 'political' reasons which compel us to continue working for this client. I agree with everything you've said and we've finally decided to pad the system down to the extent that will avoid damage even at the loudest volume, and tell the client that that is that. If they want more level, they need new speakers.
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John Roberts {JR}

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Re: Protecting speakers from nutters-Payments?
« Reply #11 on: November 18, 2010, 10:39:08 am »

Sangram Rakshit wrote on Wed, 17 November 2010 23:54

@Charlotte: Thanks - This would be fine on the input, but if Pin 1 is a floating cold pin would that not cause undesired operation?


Pin 1 is shield ground and should always be connected on properly designed gear.

Quote:


I have a E-mu 1212m with a fully balanced output, and grounding the cold end really makes it sound terrible if the amplifier is unbalanced, so I run it with pin 1 floating instead.


Hot= pin 2
Cold= pin 3
Shield=pin 1

Some poorly designed gear will have hum issues if stray shield/ground currents between chassis are allowed to corrupt the audio (bad internal design).

Some "balanced" outputs don't load sense the outputs,  so a dead short on pin 3 or pin 2 will cause distortion and lots of ground current that can cause crosstalk into other feeds.

So depending on the gear, to interface a (3 wire) balanced output to (2 wire) unbalanced input, the cold audio output line is either shorted to ground (pin 1) or left floating, which ever works best with the particular gear design.


Quote:


@Ivan - we have certain 'political' reasons which compel us to continue working for this client. I agree with everything you've said and we've finally decided to pad the system down to the extent that will avoid damage even at the loudest volume, and tell the client that that is that. If they want more level, they need new speakers.


JR

PS: I will apologize in advance for making this bad joke, but what country do customers from India get when they call customer service?  Laughing
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Sangram Rakshit

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Re: Protecting speakers from nutters-Payments?
« Reply #12 on: November 19, 2010, 12:40:20 am »

Quote:


Pin 1 is shield ground and should always be connected on properly designed gear.



Sorry I meant Pin 3.

Quote:

Some "balanced" outputs don't load sense the outputs,  so a dead short on pin 3 or pin 2 will cause distortion and lots of ground current that can cause crosstalk into other feeds.


Pretty much what I face, so I just float the ring terminal of the output TRS connector since all my downstream equipment tends to be RCA-input only.

Quote:

 what country do customers from India get when they call customer service?  Laughing


Thankfully, not the US or Britain! Laughing Laughing

Seriously though, I sympathise completely. The typical CS guy is not very fluent in English, and our language does not adequately support technical conversations. Education standards in the English language are not very good except in top-tier schools (which the masses cannot afford). It's a bit of a vicious cycle, though things have improved significantly in the last decade or so, at least from where I'm standing.

The real culprits are companies who shift the support base outside the comfort zone of their customers to lower their operating costs, instead of just making more reliable products and services. So don't blame us for everything! Smile
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John Roberts {JR}

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Re: Protecting speakers from nutters-Payments?
« Reply #13 on: November 19, 2010, 09:40:05 am »

Sangram Rakshit wrote on Thu, 18 November 2010 23:40



Quote:

 what country do customers from India get when they call customer service?  Laughing


Thankfully, not the US or Britain! Laughing Laughing

Seriously though, I sympathise completely. The typical CS guy is not very fluent in English, and our language does not adequately support technical conversations. Education standards in the English language are not very good except in top-tier schools (which the masses cannot afford). It's a bit of a vicious cycle, though things have improved significantly in the last decade or so, at least from where I'm standing.

The real culprits are companies who shift the support base outside the comfort zone of their customers to lower their operating costs, instead of just making more reliable products and services. So don't blame us for everything! Smile



Actually I find the language skills quite good, and I can understand them better than some of my neighbors in MS. It's a little passive-agressive game to make them repeat stuff over and over, and tell you their name is betty or billy, when you know it isn't.  Twisted Evil

I would much rather speak with a CS person in India with answers, than sit on hold for an hour or more.  My only bad experience was with a square problem that didn't fit into the round customer service holes available.  I had a DSL modem dropping out because of a telephone line problem. The phone company menu kept dumping me to India with folks telling me to unplug and reset my modem. I finally lied to get somebody from the telephone side to come out and fix where a squirrel was chewing on their wires. Its a sad day when you have to outsmart the customer service to get a good result.

JR





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Sangram Rakshit

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Re: Protecting speakers from nutters-Payments?
« Reply #14 on: November 30, 2010, 03:02:33 am »

Just to offer up an update on the status.

We have had this problem a few times before I ever started working with this company, so the service engineer in his infinite wisdom had already plugged in a 4.7 ohm resistor in series with the positive terminal before the signal even went to the speakers.

Unfortunately the resistor was only rated for 5 watts so it kept cooking and eventually burnt right out, all four at the same time so it's safe to assume there was a ton of power going into the system. The drivers were all safe.

We replaced all the resistors and turned the level control on the NAD preamplifier down to -12dB, plus we routed the signal through the highpass filter on the Velodyne subwoofer that was installed. Hopefully there is sufficient reduction in the power being dumped into the speakers, but it's wait and watch.
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