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Limiter / Protection for HiFI?

Doodski

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I don't think this is gonna work.

since the max current is very frequency dependent.
At very low frequency over excursion damage will happen before Thermal damage.
At low frequency there is a lot of power handling so i would need high current and slow fusses
At very high frequency the tweeter gets damaged with way less current then the bass driver.

But behind the crossover this can work an JBL did something similar
750-SK3_detail2.jpg.auto.webp
Those work excellent. I torture tested JBL Control 1 speakers and the lamp was illuminating so bright it could be seen out the porthole. I tried to fry them but the lamp saved the speakers.
 

Berwhale

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Ideally you would of cause never need this... but to make the system "idiot" proof?

So you need the audio equivalent of this...

 

maverickronin

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Most of you guys seem to be misunderstanding what @Lambda is worrying about.

I'dont think i fast enough to turn down the volume in cases some digital stream decides to send 0dBFS 4Khz Square wave...
Wen i have my volume all the way up because i was listening to verry low and dynamic track before.
If the source is youtube, twitch, soundclud,mixcloud, vimeo... or something you cant be sure what your getting is "save"

His source appears to be a general purpose computer, which is never the most stable of devices. He doesn't want some random app or website to crash and output white noise at 0dBFS while he has the volume cranked for Telarc's 1812 Overture.

@Lambda, if you could detail your signal chain we might be able to propose a better idea.
 
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Lambda

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His source appears to be a general purpose computer, which is never the most stable of devices. He doesn't want some random app or website to crash and output white noise at 0dBFS while he has the volume cranked for Telarc's 1812 Overture.
Yes you understand the concern.

@Lambda, if you could detail your signal chain we might be able to propose a better idea.
This is only a general Question if there is some system or how it could be made.

Software on the PC is one idea but i think i would prepare DSP hardware.
Maybe mini DSP can do something like this already?

Another idea is dedicated "protection" DSP system Maybe an "Arduino" that Just measures the amplifier output and in cases of to high RMS power it could shut down the amplifier or open a relay.
A programmable electronic fuse with a view Frequency depended power limits.
 

maverickronin

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This is only a general Question if there is some system or how it could be made.

Possible, but probably not the most practical unless you're already an expert or your existing speakers already have enough headroom that you can give up plenty as a safety margin. My earlier is basically that kind of generic starting point.

Software on the PC is one idea but i think i would prepare DSP hardware.

Software on the PC itself would still be prone to those same kinds of failures so I agree that external hardware would be best.

Maybe mini DSP can do something like this already?

It looks like the miniDSPs do have a limiter.

Another idea is dedicated "protection" DSP system Maybe an "Arduino" that Just measures the amplifier output and in cases of to high RMS power it could shut down the amplifier or open a relay.

Totally doable, although unless you have lots of good data on what the drivers can take without dying I don't think it would provide provide any better results than just a normal limiter.
 

Berwhale

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Maybe something could be built with Voicemeeter, EqualizerAPO and a Dynamic Range Compression (DRC) VST? i.e. route music playback directly to your DAC, but all other system sounds via the DRC first to limit their volume.
 

puppet

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Most of you guys seem to be misunderstanding what @Lambda is worrying about.



His source appears to be a general purpose computer, which is never the most stable of devices. He doesn't want some random app or website to crash and output white noise at 0dBFS while he has the volume cranked for Telarc's 1812 Overture.
Is this even a "thing" to worry about?
 

gene_stl

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Madjalapeno

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I use CamillaDSP to take 12Db out of the maximum my DAC will put out. It also means the volume control has more travel before things get too loud.

There is also a Neurochrome protection circuit (just shared by @gene_stl as I was finding the page) - https://neurochrome.com/collections/protection-control/products/guardian-686

The Guardian-686 is a high-end protection circuit designed to protect speakers against two common ways that power amplifiers can misbehave:

  • Sharp voltage transients on power-up and power-down, resulting in annoying clicks and pops in the speakers.
  • Excessive DC voltage on the output of the amplifier, for example resulting from amplifier failure or from unruly signal sources.[/ICODE]
 

maverickronin

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Is this even a "thing" to worry about?

I've had pretty nasty ones happen to me a few times over the years. Fortunately with headphones and cheap powered computer speakers which weren't damaged. Unfortunately, still plenty loud enough to leave my ears ringing a bit.
 

Kal Rubinson

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Is this even a "thing" to worry about?
I don't think so. I have been involved with high quality audio componentry for many decades and I've had only two significant relevant problems. Neither of them had to do with misuse.
1. I installed a new high-power amplifier and installed it in place of its predecessor. It was faulty with, unknown to me, a significant DC output on one channel. It blew out the woofer VC in one of my speakers.
2. I tend to leave my systems powered up and the volume control circuit failed in a preamp in the middle of the night. As a result, the system was blasting streaming music at full volume. I got out of bed and, like a salmon swimming upstream, forced my way to and into that room to pull the plug on the power amp. No damage was caused but, of course, the preamp needed repair.
I've had a few other minor events that surprised when signal-switching but they were, imho, unimportant. No pain, no damage.

That said, no one uses my systems other than me or my wife and she uses them only on rare occasion and by following written instructions. The are complex and unfriendly.
 

Doodski

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2. I tend to leave my systems powered up and the volume control circuit failed in a preamp in the middle of the night. As a result, the system was blasting streaming music at full volume. I got out of bed and, like a salmon swimming upstream, forced my way to and into that room to pull the plug on the power amp. No damage was caused but, of course, the preamp needed repair.
I've repaired I'm guessing in the hundreds of very problematic Sony STR-AV970 receivers that would turn on and then switch radio station presets, scan the radio, the volume would go to maximum and all sorts of crazy combinations of stuff. One customer told me about his, that when he was sleeping he had the same thing happen that you described. I had to chuckle when I read your commentary. :D

The issue with those was bad grounds. The ground would just slightly float and the CPU and other digital circuitry would go bonkers. I hooked up my HP analogue storage O-scope and had the CRT persistence set to capture transient voltage on the chassis ground and voila the O-scope caught a event. So I star grounded the pricks and the issues went away.
 
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Kal Rubinson

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I've repaired I'm guessing in the hundreds of very problematic Sony STR-AV970 receivers that would turn on and then switch radio station presets, scan the radio, the volume would go to maximum and all sorts of crazy combinations of stuff. One customer told me about his, that when he was sleeping he had the same thing happen that you described. I had to chuckle when I read your commentary. :D
This was Meridian preamp.
 

digitalfrost

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His source appears to be a general purpose computer, which is never the most stable of devices. He doesn't want some random app or website to crash and output white noise at 0dBFS while he has the volume cranked for Telarc's 1812 Overture.
This happened to me. Had a 200W/8ohm power amplifier hooked up to my soundcard, input sensitivity was only 0.7v (!). So all volume control through the PC. There was a bug with that specific motherboard+soundcard combination and the card sometimes put out noise at full scale (2v). First time it happened I was laying in bed skipping through the playlist. Whole house was awake. Luckily it didn't kill the speakers.
 

Doodski

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No. It was a long, long time ago and I didn't ask.
I'm always curious to see what would cause a funky issue like your Meridian had. Sometimes it's the simplest stuff (After finding the fault it seems simple anyway.) and with others it's a bad CPU or keyboard driver IC. What model of Meridian was it if you don't mind me asking? So I can google it and add it to my memory.
 

brimble

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I've had pretty nasty ones happen to me a few times over the years. Fortunately with headphones and cheap powered computer speakers which weren't damaged. Unfortunately, still plenty loud enough to leave my ears ringing a bit.
I've blown up electrostatic headphones just by turning the volume too high.
 

Kal Rubinson

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I'm always curious to see what would cause a funky issue like your Meridian had. Sometimes it's the simplest stuff (After finding the fault it seems simple anyway.) and with others it's a bad CPU or keyboard driver IC. What model of Meridian was it if you don't mind me asking? So I can google it and add it to my memory.
It was a Model 201.
 
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