Question about RFI or dirty line interference in Edifier R1900TIII.

K

KungBore

Audiophyte
Long story:

I bought these R1900TIII in 2015.

r/BudgetAudiophile - Question about RFI or dirty line interference in Edifier R1900TIII.

http://specsan.com/computer-speakers-edifier/edifier-r1900tiii/

Important note: My city has 220v power outlets and the speakers are 110v, so I've used a simple voltage converter (100VA) since always with them. The speakers do not have a ground pin.
They worked fine for a year in Apartment A. They are active 2.0 speakers that connect to each other using one of these:

r/BudgetAudiophile - Question about RFI or dirty line interference in Edifier R1900TIII.



I connect them to a TV through an RCA cable, since I use them for listening to music and watching movies / playing games:

r/BudgetAudiophile - Question about RFI or dirty line interference in Edifier R1900TIII.

In 2016, I moved to a house. Let's call it House A. No problems here either.

In 2017, I moved to House B. Again, no problems with interference whatsoever.

In 2018, I moved to Apartment B. The apartment is right next to an radio station antenna the size of the building itself (a 13-story building). There were extremely high levels of RFI (I could literally listen to the radio station). I mitigated the problem by using ferrite beads around the cables.

Now, in 2020, I moved to Apartment C. Here, there seems to be 2 different kinds of interference messing with the speakers.

- The first one is a high frequency interference that happens on both the active and the passive speakers, but ONLY when I connect them together. If I connect the active speaker alone, even if I connect the RCA cable to the TV, it doesn't hiss. If I roll the active-passive cable with ferrite beads, I can almost eliminate the hissing in the active speaker, but it only mitigates the problem in the passive speaker. Is there any kind of shielded active-passive cables?

- The second one - which bothers me the most - is a low frequency hum that happens occasionally. It sound like when you disconnect the RCA cables with the speakers on. I suspect this is a problem with the electricity of the apartment, but I can't confirm that. That low frequency hum happens even if I connect only the active speaker in the outlet (no TV, no passive speaker, no computers).

I haven't got any clues as to what to do. I'll ask a electrician to take a look, but my hopes are low about that. I'm considering to get a isolation transformer too, but I guess that could only potentially solve the low hum. I'm also considering to take the speakers to a technician.
 
Eppie

Eppie

Audioholic Samurai
The high frequency interference seems very odd. The amplifier is only located in the 'active' speaker, so the connector to the 'passive' speaker is passing an amplified signal. While unshielded cable can act like an antenna, the signal level of the interference is so small compared to that of the audio signal driving the speaker that it should never be audible. This sounds more like the signal being picked up by the speaker cable between the 2 speakers is somehow finding its way back into the amplifier which generally does not happen in modern amplifier design, unless there is some issue with the amplifier. Have you tried contacting the manufacturer?
https://www.edifier.com/int/en/support

Low level hum is typically due to grounding issues, but any intermittent problem ('happens occasionally') is the worst to have to deal with as it is not easily reproducible. Hard to say the cause, because something as simple as a loose solder connection on the power supply filter capacitors could cause a hum. First step would be to take the speakers to a qualified technician and see if the hum occurs in their shop, which would eliminate the building's electrical supply. Wish I could be of more help, but the issues you describe are probably best left to a good electronics tecnhnician, and those are getting harder to find.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Long story:

I bought these R1900TIII in 2015.

r/BudgetAudiophile - Question about RFI or dirty line interference in Edifier R1900TIII.

http://specsan.com/computer-speakers-edifier/edifier-r1900tiii/

Important note: My city has 220v power outlets and the speakers are 110v, so I've used a simple voltage converter (100VA) since always with them. The speakers do not have a ground pin.
They worked fine for a year in Apartment A. They are active 2.0 speakers that connect to each other using one of these:

r/BudgetAudiophile - Question about RFI or dirty line interference in Edifier R1900TIII.



I connect them to a TV through an RCA cable, since I use them for listening to music and watching movies / playing games:

r/BudgetAudiophile - Question about RFI or dirty line interference in Edifier R1900TIII.

In 2016, I moved to a house. Let's call it House A. No problems here either.

In 2017, I moved to House B. Again, no problems with interference whatsoever.

In 2018, I moved to Apartment B. The apartment is right next to an radio station antenna the size of the building itself (a 13-story building). There were extremely high levels of RFI (I could literally listen to the radio station). I mitigated the problem by using ferrite beads around the cables.

Now, in 2020, I moved to Apartment C. Here, there seems to be 2 different kinds of interference messing with the speakers.

- The first one is a high frequency interference that happens on both the active and the passive speakers, but ONLY when I connect them together. If I connect the active speaker alone, even if I connect the RCA cable to the TV, it doesn't hiss. If I roll the active-passive cable with ferrite beads, I can almost eliminate the hissing in the active speaker, but it only mitigates the problem in the passive speaker. Is there any kind of shielded active-passive cables?

- The second one - which bothers me the most - is a low frequency hum that happens occasionally. It sound like when you disconnect the RCA cables with the speakers on. I suspect this is a problem with the electricity of the apartment, but I can't confirm that. That low frequency hum happens even if I connect only the active speaker in the outlet (no TV, no passive speaker, no computers).

I haven't got any clues as to what to do. I'll ask a electrician to take a look, but my hopes are low about that. I'm considering to get a isolation transformer too, but I guess that could only potentially solve the low hum. I'm also considering to take the speakers to a technician.
Being close to a radio station is a big problem. RF interference is a big problem in those cases.

Since the speakers are active they would need modification. That will be impossible unless you have access to the circuits in the speakers. It sounds as if it is the carrier frequency of the station that is causing the trouble. Not all these cases are solvable whatever you do. But the task is to design rejector circuits and sometimes acceptor circuits tuned to the radio station in question at critical points in the circuit. This is usually beyond the scope of repair technicians.

Your easiest solution is to move again.
 
K

KungBore

Audiophyte
The high frequency interference seems very odd. The amplifier is only located in the 'active' speaker, so the connector to the 'passive' speaker is passing an amplified signal. While unshielded cable can act like an antenna, the signal level of the interference is so small compared to that of the audio signal driving the speaker that it should never be audible. This sounds more like the signal being picked up by the speaker cable between the 2 speakers is somehow finding its way back into the amplifier which generally does not happen in modern amplifier design, unless there is some issue with the amplifier. Have you tried contacting the manufacturer?
https://www.edifier.com/int/en/support

Low level hum is typically due to grounding issues, but any intermittent problem ('happens occasionally') is the worst to have to deal with as it is not easily reproducible. Hard to say the cause, because something as simple as a loose solder connection on the power supply filter capacitors could cause a hum. First step would be to take the speakers to a qualified technician and see if the hum occurs in their shop, which would eliminate the building's electrical supply. Wish I could be of more help, but the issues you describe are probably best left to a good electronics tecnhnician, and those are getting harder to find.
Hey!
I've contacted them, but they asked me to send the speakers in, so I just gave up, since it would be quite expensive and possibility not solve the issue.

I took the speakers to a technician and they didn't have any issues. They don't have the issue in other rooms of the apartment too. I guess I'll just move the stuff from this room to another and check if the issue really goes away. Thanks anyway!

Being close to a radio station is a big problem. RF interference is a big problem in those cases.

Since the speakers are active they would need modification. That will be impossible unless you have access to the circuits in the speakers. It sounds as if it is the carrier frequency of the station that is causing the trouble. Not all these cases are solvable whatever you do. But the task is to design rejector circuits and sometimes acceptor circuits tuned to the radio station in question at critical points in the circuit. This is usually beyond the scope of repair technicians.

Your easiest solution is to move again.
Actually, the easiest solution might just be to move the speakers to another room and check if the issue really goes away, since I've tested for a bit and the only room with the issue is this one, but I need some time testing to check the low frequency hum too, since it's intermitent.

I was wondering if a pair of passive speakers + amplifier wouldn't have the problem... How do they differ in terms of RFI? Maybe that could my next step if another room doesn't work.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Hey!
I've contacted them, but they asked me to send the speakers in, so I just gave up, since it would be quite expensive and possibility not solve the issue.

I took the speakers to a technician and they didn't have any issues. They don't have the issue in other rooms of the apartment too. I guess I'll just move the stuff from this room to another and check if the issue really goes away. Thanks anyway!



Actually, the easiest solution might just be to move the speakers to another room and check if the issue really goes away, since I've tested for a bit and the only room with the issue is this one, but I need some time testing to check the low frequency hum too, since it's intermitent.

I was wondering if a pair of passive speakers + amplifier wouldn't have the problem... How do they differ in terms of RFI? Maybe that could my next step if another room doesn't work.
Passive speakers would almost certainly be much worse. The speaker leads are longer and really pick up RF, and feed it back to the high gain stages through the negative feedback circuits.
 
S

Speedskater

Audioholic Chief
Try ferrite's on every cable near where they enter the powered loudspeaker.
 
Eppie

Eppie

Audioholic Samurai
Passive speakers would almost certainly be much worse. The speaker leads are longer and really pick up RF, and feed it back to the high gain stages through the negative feedback circuits.
Actually, the easiest solution might just be to move the speakers to another room and check if the issue really goes away, since I've tested for a bit and the only room with the issue is this one, but I need some time testing to check the low frequency hum too, since it's intermittence.

I was wondering if a pair of passive speakers + amplifier wouldn't have the problem... How do they differ in terms of RFI? Maybe that could my next step if another room doesn't work.
That's going to depend upon the amplifier design so I don't entirely agree with such a broad statement that passives will be worse. It's possible that the powered speaker has an unshielded amplifier and that a discrete integrated amp would be less susceptible to the RF interference, either by amp design or better shielding. My neighbour had a HAM radio transmitter which caused interference on a Kenwood receiver. I could occasionally hear voices, and since the volume was always the same I knew it was from the amplifier stage. No such issues when I changed to a Denon home theatre receiver.

This is one tricky problem. RF can be reflected, like sound waves, so you can have places in the apartment where the interference is worse, like how bass can sound boomy in some corners of a room. Moving the equipment around is certainly worth a try, as well as trying different electrical outlets. Even changing the orientation of the wires and equipment can make a difference. Additional ferrites won't hurt either but won't help with the hum. Would be nice if you could borrow audio equipment to test with to see if the powered speaker is the issue. I think it's going to be a process of elimination.

Oh, and speaking of hum, a UPS or uninterruptible power supply like people buy for computers could provide a cheaper solution for the hum. This would need to be a model that does more than just surge protection. You need a smart model that does power conditioning, like boosting low voltages in a brown out. You would need to match the power requirements of your powered speaker with the output of the UPS, but I don't think that will be an issue. Quick search says the speaker is rated at 25Wx2 so it probably draws less than 100W from the wall (it will say on the back of the speaker near the power cord). Even the smaller UPS models are rated at 550VA-650VA which should be enough for that speaker.

Let us know if you have any success.
 
K

KungBore

Audiophyte
I've just moved them to another room where I hadn't noticed the problem and voilà , it has been working fine so far. I only needed to put a couple of ferrite cores on both ends of the speaker cables to remove the little white noise it still had.


Passive speakers would almost certainly be much worse. The speaker leads are longer and really pick up RF, and feed it back to the high gain stages through the negative feedback circuits.
Try ferrite's on every cable near where they enter the powered loudspeaker.
That's going to depend upon the amplifier design so I don't entirely agree with such a broad statement that passives will be worse. It's possible that the powered speaker has an unshielded amplifier and that a discrete integrated amp would be less susceptible to the RF interference, either by amp design or better shielding. My neighbour had a HAM radio transmitter which caused interference on a Kenwood receiver. I could occasionally hear voices, and since the volume was always the same I knew it was from the amplifier stage. No such issues when I changed to a Denon home theatre receiver.

This is one tricky problem. RF can be reflected, like sound waves, so you can have places in the apartment where the interference is worse, like how bass can sound boomy in some corners of a room. Moving the equipment around is certainly worth a try, as well as trying different electrical outlets. Even changing the orientation of the wires and equipment can make a difference. Additional ferrites won't hurt either but won't help with the hum. Would be nice if you could borrow audio equipment to test with to see if the powered speaker is the issue. I think it's going to be a process of elimination.

Oh, and speaking of hum, a UPS or uninterruptible power supply like people buy for computers could provide a cheaper solution for the hum. This would need to be a model that does more than just surge protection. You need a smart model that does power conditioning, like boosting low voltages in a brown out. You would need to match the power requirements of your powered speaker with the output of the UPS, but I don't think that will be an issue. Quick search says the speaker is rated at 25Wx2 so it probably draws less than 100W from the wall (it will say on the back of the speaker near the power cord). Even the smaller UPS models are rated at 550VA-650VA which should be enough for that speaker.

Let us know if you have any success.
Thanks for the extra input guys! I'll definitively keep these in mind if I had trouble in the future. I was wondering, could the fiber wiring of my internet provider be the culprit of the low hum? The router is installed in the previous room.
 
Eppie

Eppie

Audioholic Samurai
Thanks for the extra input guys! I'll definitively keep these in mind if I had trouble in the future. I was wondering, could the fiber wiring of my internet provider be the culprit of the low hum? The router is installed in the previous room.
Nice to hear that the RF noise was eliminated. As to the hum, unlikely the router, but you could simply unplug its power adapter to test that. Some power adapters are made cheaply and can radiate noise. The challenge here is that the hum can be from the speaker's internal power supply, other components or from the apartment wiring. You said the technician found nothing wrong, so the internal power supply should be ok. If you unplug all components (music sources) from the speaker inputs and still get the hum, then you have eliminated any ground loops occurring between the components and the speakers. If the hum goes away, try plugging the speakers and a component into the same electrical outlet, or reversing the plug on one piece. Are the plugs polarized (only plug in one way)? If you can test the speakers somewhere else and eliminate the hum, then you know the apartment or your components are the issue. If the apartment, I would lean towards a battery backup power supply with line conditioning. Even if it doesn't fix the issue, you can still use it on your computer for surge protection, so not a total waste.
 

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