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Author Topic: Blown Subwoofers and Looking for Replacement  (Read 9774 times)

Ivan Beaver

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Re: Blown Subwoofers and Looking for Replacement
« Reply #30 on: May 24, 2016, 07:48:57 am »

I still don't agree with limiting to long term ratings, limit to peak, you pretty much wasting your money if you limit to program power.


I disagree.

If you set the limit to the peak, then there is a VERY GOOD possibility of blowing up gear.

Each situation is different, with different type of music, different levels of operators.

For the "stupid level", I suggest limiting with a slow attack ( 3 seconds or so-shorter for higher freq units) at around 1/3 the continuous rating of the sub.

This will allow the peaks to come through (and hopefully not hit the excursion limit of the driver).

But if the average level gets to high for to long, it will be limited.

REMEMBER that the power ratings are based on a specific test signal for a specific time.

Once you are outside that, all sorts of things can happen.

If you don't have a slow attack limiter, then limiting around the continuous rating is a good idea.

Again-the peaks will come through.

The KEY to limiters is the ATTACK time and how it relates to the limiting voltage.

I really prefer 3 limiters.  For subs this would be a slow with attack at 3 seconds and the voltage around 1/3 the continuous rating.

A program with an attack around 20-30ms at the voltage rating of the sub.

A peak with a fast (as fast as possible) that is at 1.4-2 times (voltage) the continuous rating.

Given a choice of where to put them in line-the slow goes first with the fast at the end.
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Jean-Pierre Coetzee

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Re: Blown Subwoofers and Looking for Replacement
« Reply #31 on: May 24, 2016, 12:59:33 pm »

I disagree.

If you set the limit to the peak, then there is a VERY GOOD possibility of blowing up gear.

Each situation is different, with different type of music, different levels of operators.

For the "stupid level", I suggest limiting with a slow attack ( 3 seconds or so-shorter for higher freq units) at around 1/3 the continuous rating of the sub.

This will allow the peaks to come through (and hopefully not hit the excursion limit of the driver).

But if the average level gets to high for to long, it will be limited.

REMEMBER that the power ratings are based on a specific test signal for a specific time.

Once you are outside that, all sorts of things can happen.

If you don't have a slow attack limiter, then limiting around the continuous rating is a good idea.

Again-the peaks will come through.

The KEY to limiters is the ATTACK time and how it relates to the limiting voltage.

I really prefer 3 limiters.  For subs this would be a slow with attack at 3 seconds and the voltage around 1/3 the continuous rating.

A program with an attack around 20-30ms at the voltage rating of the sub.

A peak with a fast (as fast as possible) that is at 1.4-2 times (voltage) the continuous rating.

Given a choice of where to put them in line-the slow goes first with the fast at the end.

My apologies Ivan, I did kind of mean rating The amplifier to peak but I didn't state that correctly, your limiting idea seems to be very good but not sure if the opportunity has access to that kind of limiting and likewise not sure if the opportunity should be fiddling with something that the installer seem to have setup correctly in the first place.
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Rob Spence

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Re: Blown Subwoofers and Looking for Replacement
« Reply #32 on: May 24, 2016, 04:44:20 pm »

Did we ever learn what the failure mode was so we are working to prevent a repeat?
I lost track so it may have been stated.


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Jean-Pierre Coetzee

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Re: Blown Subwoofers and Looking for Replacement
« Reply #33 on: May 24, 2016, 05:04:42 pm »

Did we ever learn what the failure mode was so we are working to prevent a repeat?
I lost track so it may have been stated.


Sent from my iPad using Tapatalk HD
From what I can tell exceeded long term power rating which burnt the voice coil,  probably from being driven hard for some period of time probably with the desk at clip or something similar since it seems to me the SI2 cannot swing enough voltage to send the amp into clip.
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Don Sullivan

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Re: Blown Subwoofers and Looking for Replacement
« Reply #34 on: May 26, 2016, 08:46:29 pm »

I like the multiple limiter concept, in fact I use my console output ( on digital boards) by adding a 2:1 zero attack compressor about 6 db down from where my system controller limiter kicks in. You can hear it and see on the console output meters when you approach your system limits.

As for "clipping" it is popularized as the bogey-man of audio that is somehow solely responsible for burning your precious voice coils. You can and will damage voice coils before clipping a powerful amp. Thermal overload is your enemy. As for wasting amp power, yes, you may easily buy more amp than you need. Don't forget we are talking about logarithmic values and even a front loaded music-store bought sub can manage 80-90 decibels with one watt of power. The top half or third of your amp wattage may rarely be used or even needed. You generally benefit more from adding speakers than adding watts.
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Ivan Beaver

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Re: Blown Subwoofers and Looking for Replacement
« Reply #35 on: May 27, 2016, 07:41:24 am »

I like the multiple limiter concept, in fact I use my console output ( on digital boards) by adding a 2:1 zero attack compressor about 6 db down from where my system controller limiter kicks in. You can hear it and see on the console output meters when you approach your system limits.


That is not a bad idea.  It gives you a gently reduction that most people cannot hear (unless they see it on the meter).

And at the point of where you are near system limit, most peoples ears have started to "shut down" and go into auto protect mode.

So a subtle reduction is not noticeable.  But the extra power being delivered to the loudspeaker IS noticeable by the loudspeaker.

They like it better with less power being applied. :)
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

ProSoundWeb Community

Re: Blown Subwoofers and Looking for Replacement
« Reply #35 on: May 27, 2016, 07:41:24 am »


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