Hi people!
I'm new to the diyAudio community!
Unfortunately as awesome as my newness is, my problem isn't. I have a stereo setup for my computer which I use to make music (non-professional). Here's my setup:
Computer -(USB)>
Audio Interface/DAC -(using a male 3.5mm to male 2xRCA cable)>
Class-D Amp -(Copper wire from speakers)>
Stereo Hi-Fi Speakers
Recently, there's been a popping/crackling sound coming out of my speakers even when there is nothing being played. And so I did some investigation myself and here is what I found:
- Crackling is periodic (i.e. the pops/crackles are like beats ~130BPM).
- Crackling is exactly the same on both speakers.
- Audio input (on or off) and/or volume level does not affect the crackling.
- Changing the voltage input (of my amp) changes the characteristic of the crackling.
- Unplugging the line from the Audio Interface while leaving it plugged into the amp makes the crackling louder and there is a mid-low frequency hum.
- Unplugging the line from the amp, the crackling and everything almost disappears, but the same characteristic popping/crackling sound can be heard very slightly, if you get close to the speakers (~5cm from the drivers).
- Here's what is the most strangest; Plugging the input of the amp to my phone the problem persists until something is played. After which it seems everything is fixed... What I know about my phone is that it turns off output to the 3.5mm socket if nothing is being played to save power. My other question is; does the fact that the 3.5mm socket in my phone is designed for headsets (not just audio out) have anything to do with this?
Please let me know what you guys think, as right of now, the only thing I haven't done is smashed my speakers up (the popping sound is infernal)...
I'm new to the diyAudio community!
Unfortunately as awesome as my newness is, my problem isn't. I have a stereo setup for my computer which I use to make music (non-professional). Here's my setup:Computer -(USB)>
Audio Interface/DAC -(using a male 3.5mm to male 2xRCA cable)>
Class-D Amp -(Copper wire from speakers)>
Stereo Hi-Fi Speakers
Recently, there's been a popping/crackling sound coming out of my speakers even when there is nothing being played. And so I did some investigation myself and here is what I found:
- Crackling is periodic (i.e. the pops/crackles are like beats ~130BPM).
- Crackling is exactly the same on both speakers.
- Audio input (on or off) and/or volume level does not affect the crackling.
- Changing the voltage input (of my amp) changes the characteristic of the crackling.
- Unplugging the line from the Audio Interface while leaving it plugged into the amp makes the crackling louder and there is a mid-low frequency hum.
- Unplugging the line from the amp, the crackling and everything almost disappears, but the same characteristic popping/crackling sound can be heard very slightly, if you get close to the speakers (~5cm from the drivers).
- Here's what is the most strangest; Plugging the input of the amp to my phone the problem persists until something is played. After which it seems everything is fixed...
What I know about my phone is that it turns off output to the 3.5mm socket if nothing is being played to save power. My other question is; does the fact that the 3.5mm socket in my phone is designed for headsets (not just audio out) have anything to do with this?Please let me know what you guys think, as right of now, the only thing I haven't done is smashed my speakers up (the popping sound is infernal)...
Does the interference still occur with a different audio cable?
Does a different amplifier give the same results?
Do different speaker give the same result?
The "headset" fourth connection is for the microphone and is shorted when "normal" headphones are used...I do not believe it is an issue.
Does a different amplifier give the same results?
Do different speaker give the same result?
The "headset" fourth connection is for the microphone and is shorted when "normal" headphones are used...I do not believe it is an issue.
Hi Doug, firstly thanks for your reply. Here are my ans' to your questions.
"Does the interference still occur with a different audio cable?"
I have tried different cables (for connecting my Interface to the amp) and the interference is the same.
"Does a different amplifier give the same results?"
Unfortunately, I do not have access to another amp.
"Do different speaker give the same result?"
Unfortunately, I do not have another set of speakers either.
It has been about 5 hours since I switched on my amp today (with the same problem to start with), and the popping/crackling has slowly gone away. However, I am am unsure if turning the amp off and back on again would result in the popping/crackling coming back so I am going to have to wait till later today (I want to use the speakers as, for the moment being, they're functioning normally). I will probably test it tonight to see if turning it off and on again results in the problem coming back.
"Does the interference still occur with a different audio cable?"
I have tried different cables (for connecting my Interface to the amp) and the interference is the same.
"Does a different amplifier give the same results?"
Unfortunately, I do not have access to another amp.
"Do different speaker give the same result?"
Unfortunately, I do not have another set of speakers either.
It has been about 5 hours since I switched on my amp today (with the same problem to start with), and the popping/crackling has slowly gone away. However, I am am unsure if turning the amp off and back on again would result in the popping/crackling coming back so I am going to have to wait till later today (I want to use the speakers as, for the moment being, they're functioning normally). I will probably test it tonight to see if turning it off and on again results in the problem coming back.
Hi DF96, thanks for you're reply. I did consider that as a possible problem when this issue first started happening, and so took my phone out of my room and a considerable distance away - it didn't do anything. So I guess we can rule out my phone as an interference factor.
Continuing on from DUG's reply from yesterday, as randomly as my problem went away, it came back before I turned off my amp last night. Now that I've turned it back on this morning, we're back to square one (in terms of the popping/crackling).
I would also like to add that I do not live in an industrial area, if it may help (I've come across certain issues of interferences on the web where people turned out to be living in some sort of industrial area).
Do you have an aircon or refrigerator running?
CFL or LED lamps?
Can you check to make sure you do not have DC from your preamp output
Check to see that with no input to your amp, you also have no DC on the amplifier output (with speakers connected)
If it's at 130 BPM it may be motorboating - low freq oscillation.
If it is this, it will require some sleuthing.
CFL or LED lamps?
Can you check to make sure you do not have DC from your preamp output
Check to see that with no input to your amp, you also have no DC on the amplifier output (with speakers connected)
If it's at 130 BPM it may be motorboating - low freq oscillation.
If it is this, it will require some sleuthing.
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Hi Bonsai, thanks for the reply.
I do have a CFL bulb in my room, but its always turned off during daytime. My refrigerator is in my kitchen is always powered/plugged in to a wall socket there. The CFL being powered on/off doesn't seem to affect the popping.
Unfortunately, I do not have access to a multi-meter or anything similar so I can't quite measure voltages/currents etc.
Updating my story; it has been 3 hours since I powered on my amp today, and the popping/crackling has gone away just like from my post yesterday. However, it seems that the duration the amp is turned on is not affecting the popping, but the time of the day. During daytime, the popping/crackling slowly disappears, and as night falls eventually it comes back...
I do have a CFL bulb in my room, but its always turned off during daytime. My refrigerator is in my kitchen is always powered/plugged in to a wall socket there. The CFL being powered on/off doesn't seem to affect the popping.
Unfortunately, I do not have access to a multi-meter or anything similar so I can't quite measure voltages/currents etc.
Updating my story; it has been 3 hours since I powered on my amp today, and the popping/crackling has gone away just like from my post yesterday. However, it seems that the duration the amp is turned on is not affecting the popping, but the time of the day. During daytime, the popping/crackling slowly disappears, and as night falls eventually it comes back...
When all else fails, try the trouble shooting section of this Bill Whitlock paper (about page 100):
http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
Or this Jim Brown interference paper:
http://www.audiosystemsgroup.com/RFI-Ham.pdf
Many other Jim Brown interference papers at:
Audio Systems Group, Inc. Publications
http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf
Or this Jim Brown interference paper:
http://www.audiosystemsgroup.com/RFI-Ham.pdf
Many other Jim Brown interference papers at:
Audio Systems Group, Inc. Publications
You're not in an industrial area but are you rural or nearby...?
Electric stock fence interference...? They pulse at anywhere from 1 to 2 pulses/second. Usually affects phones more than hifi but who knows.
I have had problems with neighbours not checking their fences for damage and, back in dial-up modem days, having my internet connection unusable due the spikes induced that caused the modem to drop out..
Electric Fence Interference
Got a neighbour with a dog-training fence on their property ?
Electric stock fence interference...? They pulse at anywhere from 1 to 2 pulses/second. Usually affects phones more than hifi but who knows.
I have had problems with neighbours not checking their fences for damage and, back in dial-up modem days, having my internet connection unusable due the spikes induced that caused the modem to drop out..
Electric Fence Interference
Got a neighbour with a dog-training fence on their property ?
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Thanks for the replies everyone. But it seems that I don't have proper equipment to diagnose this problem myself. The workaround meanwhile however is that the problem slowly disappears (on its own) over time... I honestly have no clue why. So I am just gonna stick with it for the moment being. Maybe in the future, I'll just get a pair of powered studio monitors that I can connect using balanced cables.
Thanks again for all the replies!
Thanks again for all the replies!
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