[SOLVED] Apartment ventilation and popping sound from speakers.

[crazzzik]

Hello everyone,

I've just moved to a new apartment with central heat. All is good except for one concerning occurrence.

You see, every time ventilation kicks in, my computer speakers emit a loud popping sound and become louder for some time. Those two events are clearly linked. Property management swears that ventilation and my outlet are on different fuses. As for speakers, I'm using A2+ from audioengine. These are externally powered active speakers. They are hooked up to Belkin surge protecting power strip. From the audio side, speakers hooked up to PC via usb + output from them is piped through standalone passive bass crossover and into a subwoofer that is also connected to the same power bar. Didn't have this issue at the last place.

I'm concerned that it may harm my set in any way. Do you have any ideas what it might be?

UPDATE: One big thing that I forgot to mention is that the whole apartment is carpet floors. So static is at play as well. Also, I found that it is the subwoofer that is sending a feedback through audio cable back into speakers. I ended up buying a UPS with adaptive sine wave correction. Since then it only happened once or twice so I still have to try and insulate it from the carpet, but it is miles better than it used to be. Thank you all for useful tips!

[HAL-42b]

Thou Shalt Measure Voltages. 

[ECEdesign]

Im not in power but it sounds like there might be some voltage spikes or some sort of RF noise.  Your surge protector should be helping.  You could try to monitor the mains with a safe meter or if you had a HV differential probe for your oscilloscope that might give some insight.   

[dannyf]

Sounds like time for better speakers or speakers with better power supply or input conditioning / shielding.

[cdev]

Try putting some ferrite split beads on the input cables, maybe wrap the cable several times through one tightly. As many times as will fit. If it has a separate power brick and the above does not work, do the same thing with its cable.

[Stray Electron]

Hello everyone,

I've just moved to a new apartment with central heat. All is good except for one concerning occurrence.

You see, every time ventilation kicks in, my computer speakers emit a loud popping sound and become louder for some time. Those two events are clearly linked. Property management swears that ventilation and my outlet are on different fuses. As for speakers, I'm using A2+ from audioengine. These are externally powered active speakers. They are hooked up to Belkin surge protecting power strip. From the audio side, speakers hooked up to PC via usb + output from them is piped through standalone passive bass crossover and into a subwoofer that is also connected to the same power bar. Didn't have this issue at the last place.

I'm concerned that it may harm my set in any way. Do you have any ideas what it might be?

   It sounds like the wiring coming into the building is too small.  The ventilation is probably part of the heating system and use resistance heaters and the heater is turning on at the time that the ventilation is.  Resistance heaters (and heat pumps both) use a huge amount of power and even if they're on a separate branch of the circuit from your stereo, they're still fed from the same incoming line that's why your stereo reacts when it licks in.  In fact, the fact that it last some time tells me that somewhere there's a large motor starting up and it takes some seconds before the starter circuit in those disengages and the current draw drops and the voltage returns to normal.  The best way to deal with this is to use a constant voltage transformer to fed the stereo.  A constant voltage transformer is common electrical device, buy a real one, don't buy some goofy audiopile gimmick.

   If you want to see what's going on with the power line, look for a Power Line Disturbance Analyzer.  These are made by Dranetz and others and are made for detecting and recording events like this.  You can often pick them up surplus or off of E-bay cheaply since few people know what they are.

[amyk]

Better a popping sound than a pooping sound...

Since it's ventilation, could it be something as simple as a small air pressure change causing the speaker cones to move?

[ECEdesign]

Ferrite beads are a good idea