Any way how to simply prevent speakers from clunking?

[Behemot]

I guess you all know that, as most speakers use simple transformer to get voltage down, a voltage spike occurs when you turn them on. That results into loud clunk when. Is there any simple way how to prevent this phenomenon? A thermistor maybe?

[budm]

Re: Any way how to simply prevent speakers from clunking?

You can build delay-on speaker relay circuit to let the amp and power supply to be stable before the speaker is connected to the amp output.
Or you can buy the pre-assembled spekeaker protection that will have delay on and also DC detection to protect the speaker from damage due so failed output section that will dump DC to the speaker. Solid state amp does not use matching transformer like tube type amplifier.
Just Google "speaker protection circuits"
I.E.
http://sound.westhost.com/project33.htm
If you have separate pre-amp and power amp setup, the pre-amp should be powered up first, then the power amp. On turn off, the power amp should be turn off fist, then the pre-amp.

[goontron]

Re: Any way how to simply prevent speakers from clunking?

go back to valve amps that don't klunk?!?

[Behemot]

Re: Any way how to simply prevent speakers from clunking?

Just to get things straight, this only happens when you turn the power switch on. It is not really a functional problem but customer asked me if there is any simple improvement I can do on the main speaker with PSU to supress this.

[mariushm]

Re: Any way how to simply prevent speakers from clunking?

Add a relay and a resistor + capacitor. Capacitor charges slowly due to current limited by the resistor ... when voltage goes above a threshold (usually 6-8v for 12v rated relays), the relay turns on and remains on.

[budm]

Re: Any way how to simply prevent speakers from clunking?

That is, the power supply and the amp is not quite stable yet when the it is first powered up so it produces the thumb at the turn on, that is why it needs to have speaker delay-on so the speaker is not connected to the amp terminal until the circuit is stabled first.
I.E.
http://www.the12volt.com/installbay/...42&DIR=N&FID=5

[Behemot]

Re: Any way how to simply prevent speakers from clunking?

Yeah but you know the cheap and many of semi-decent speaker systems. This is some kidn of Genius I think. They quite often use few not-that-bad parts for their price but they have to lower the price somewhere

Yeah, slowly charging cap seems simple enough. Any suggestion for capacity and resistance? I have never really played with that and scope, have no idea how much can different resistance impact different capacitor charging

[larrymoencurly]

Re: Any way how to simply prevent speakers from clunking?

I put a capacitor across the voltage regulators for the input stage (one for the positive side, another for the negative) to bring up its voltage gradually.

[Logistics]

Re: Any way how to simply prevent speakers from clunking?

Is this an inexpensive system that may use internal OpAmps which utilize an SVR cap? Increase the capacitance of the SVR cap.

[Behemot]

Re: Any way how to simply prevent speakers from clunking?

One of those Genius cheap wooden things.

[momaka]

Re: Any way how to simply prevent speakers from clunking?

Is this an inexpensive system that may use internal OpAmps which utilize an SVR cap? Increase the capacitance of the SVR cap.

^ What he said. This also applies to some IC amplifiers as well - increase the capacitance of the input coupling capacitors, and the pop-noise disappears. However, I have found that some IC amplifiers behave exactly the opposite of this, like for example the TDA8947J and TFA9843J found in Dell MMS 5650 speaker systems. I tried upping the input coupling caps and I got much worse pop noise.

Also, some IC amplifiers like the TA8216H will have a pin specifically dedicated for reducing speaker pop. On this pin you insert a capacitor, and the bigger the capacitor value, the longer it will take for main amplifier circuit in the IC to turn on, thus eliminating speaker popping noise.

Lastly, if the IC has a pin for mute, you can use that with an RC low-pass filter to slowly bring out the IC from mute to ON. This should also remove popping noises.

A relay circuit will do as well, as mariushm suggested, but you might need some really large capacitors and large, low-resistance resistors to accomplish this, depending on how much power the relay uses. You can avoid this, however, by adding 1 transistor to turn ON/OFF the relay and have a simple RC low-pass filter network in parallel with the bias resistor network on the transistor's base pin (essentially, what you have in an amplifier that turns on very slowly). By playing with the time constant of the RC low-pass filter, you can control how long it takes before the relay turns on. (let me know if you want me to draw you schematics)

[tmiha71]

Re: Any way how to simply prevent speakers from clunking?

Or increase ESR of caps behind rectifier (speaking of linear regulator), you will lower inrush current (less di/dt and that is /in audio/ always bad )...

Personally don't like relays (or mechanical switches - in general) in paths to speakers (they toggle few times (or tenth times) before settling)...

[tmiha71]

Re: Any way how to simply prevent speakers from clunking?

(less di/dt and that is /in audio/ always bad )...

To correct myself - should be
(less di/dt and that is /in audio/ always good )

[popeye]

Re: Any way how to simply prevent speakers from clunking?

just turn the volume down before switching off or mute until your ready to use it.

[Behemot]

Re: Any way how to simply prevent speakers from clunking?

That ain't no solution, that's just healing the symptoms!

[Logistics]

Re: Any way how to simply prevent speakers from clunking?

Also, some IC amplifiers will have a pin specifically dedicated for reducing speaker pop. On this pin you insert a capacitor, and the bigger the capacitor value, the longer it will take for main amplifier circuit in the IC to turn on, thus eliminating speaker popping.

That is exactly what I was referring to--Supply Voltage Rejection capacitor.

[tom66]

Re: Any way how to simply prevent speakers from clunking?

One of the methods I used for a headphone amp with a maximum output power of 100mW was a series-connected pair of back-to-back FETs. These are driven to short the output as the amp first powers on and when it powers off. They are biased to -6V when operational. This was for a "hi fi" audiophile thing (as spec'd by customer), so we had to have as little as possible in the path from the amplifier IC to the output.