USB Audio Interface electronics issues

[JonPorobil]

Two problems.

First up: every night around 9pm, my speakers begin to play a very faint radio signal. Usually mariachi music or commercials. One time I held it up to my ear and heard a baseball broadcast. It's very faint, and its volume doesn't change unless I adjust the volume on my speakers themselves (in other words, it doesn't react to the volume control on my Lexicon Lambda or my computer's internal volume control). However, it does stop when I turn the computer off. Just for reference, the speakers are attached via 1/8" phone jack to the "headphone" slot on my Lambda, and the Lambda is attached via USB 2.0 to the computer. And again, this only happens at night.

Any idea what might cause this, and whether or not it's preventable?

Got another one, this time a little more involved.

Second issue: Whenever my air-conditioning or my neighbor's air conditioning turns on or off, the speakers crackle like mad, regardless of whether the computer is even on. I've been avoiding this mostly by unplugging my speakers after shutting down the computer for the night, but sometimes I forget this step, and it always results in a rude awakening. Here's the chains: The speakers are plugged into a surge protector, which is plugged into a wall outlet. The speakers are also plugged in (via 1/8" phone jack) to my Lexicon Lambda, which is plugged into the computer via USB 2.0. The computer's power supply is plugged into the same surge protector as the speakers.

To the best of my knowledge, the Lambda doesn't draw power from the computer when the computer is off. Nonetheless, the crazy crackling happens every time the A/C unit kicks on or deactivates, even if the computer is off. It's usually frightening and always annoying. The crackle does not occur when the speakers are plugged directly into the output on my computer, which points pretty clearly to the Lambda being at fault. Is it "supposed" to do this? By which I mean, is this a known behavior of the electronic components? Is there any kind of workaround? In addition to waking us up at night, I worry that this is potentially damaging my hardware.

[Manhattan Glutton]

Try different outlets and/or using a ground lift (if it has a pin), at least for the first issue. Sometimes circuits end up accidentally forming an excellent antenna.

I presume the lambda is already plugged into the surge protector.

[JonPorobil]

Try different outlets and/or using a ground lift (if it has a pin), at least for the first issue. Sometimes circuits end up accidentally forming an excellent antenna.

I presume the lambda is already plugged into the surge protector.

The Lambda is USB-powered.

[JonPorobil]

Describing connections among devices is complicated, and always feels rather inexact. Here's an MS-Paint diagram. The thin black line is a USB cable. The thick black lines are AC power cord. The green lines are 1/8" speaker cable.

[Manhattan Glutton]

Hmm, could be a computer issue. Have you tried plugging it into different USB slots? And plugging the computer into different outlets?

Occasionally, front USB panels can lack proper grounding.

[JonPorobil]

Hmm, could be a computer issue. Have you tried plugging it into different USB slots? And plugging the computer into different outlets?

Occasionally, front USB panels can lack proper grounding.

Iiiinteresting.

I haven't tried moving the USB to different slots, but I did recently move the computer to a different outlet.
Problem 1 (the radio interference) was always there, and changing outlets didn't help.
Problem 2 (the Air Conditioner interference) was there before, but not nearly as bad before I moved the computer.

I'll try it with different USB slots, and maybe I'll crack open the computer to see about how the USB sockets are situated on the motherboard.

Because I only just recently rearranged the whole freaking room, let's assume that the computer cannot move again. There's no other outlet for another twenty feet or so. Would it be worth it to attach everything to a long extension cord? Barring that, does it seem likely that these surges are damaging my equipment? I'll just keep putting up with it and trying to remember to unplug the speakers at night, just so long as the computer isn't suffering any real damage.

[AJOwens]

For the first issue, next time it happens, try plugging the Lambda (EDIT: I meant "speakers") directly into the wall instead of the surge connector. If that makes no difference, then never mind. I'm thinking it might be some kind of ground loop or freak tuned circuit involving the PC and Lambda power supply cables and the surge protector, but it's all rather hazy. The 9 p.m. phenomenon suggests something to do with AM radio "skip". For sure it's a weird one.

For the second issue: you say the speakers crackle if the air conditioning goes off or on -- meaning, just briefly while the state of the air conditioner changes?

If so, it could be a cable picking up EMF from the sudden massive change in current in the AC wiring in the walls. Since it doesn't happen when you connect the speakers directly to the computer, then -- assuming this is the same cable you normally use to connect the speakers to the Lambda -- it's probably not the speaker cable.

It could be the USB cable from the PC to the Lambda. Try moving it to a different location, if you can, or reorienting it. EDIT: Or using a shorter one.

[ken]

This definitely sounds like an electricity issue.

You don't mention what kind of speakers you are using, but they sound like computer speakers to me. Your lambda must have some actual outputs. Have you tried using them instead of the headphone out?

Also, what kind of surge protector are you using? Is it whatever cheap thing you had lying around? Perhaps a power conditioner would help with these issues?

http://www.musiciansfriend.com/accessor ... 5000000000

http://www.musiciansfriend.com/accessor ... 5000001000

Ken

[Manhattan Glutton]

Yeah a power conditioner, or maybe a power backup if you have one of those laying around.

Heheh, just playing devil's advocate, but if you're going to buy a power thing you might want to buy a new audio unit and see if it handles things more gracefully... if so, keep it and enjoy 64-bit drivers! If not, return it!

[JonPorobil]

This definitely sounds like an electricity issue.

You don't mention what kind of speakers you are using, but they sound like computer speakers to me. Your lambda must have some actual outputs. Have you tried using them instead of the headphone out?

Also, what kind of surge protector are you using? Is it whatever cheap thing you had lying around? Perhaps a power conditioner would help with these issues?

http://www.musiciansfriend.com/accessor ... 5000000000

http://www.musiciansfriend.com/accessor ... 5000001000

Ken

Part of it may be that my equipment is good, but aging. The surge protector is a full-on protector with a siren and LED indicator that are supposed to activate in the event of an actual power surge. But it might not be 100% reliable because it's about eight years old. The speakers, as well, are good, but aging. They're JBL ("Creature" model) speakers, one subwoofer and two satellites. I bought them in 2004.

Also, the "Headphones" output on the front is the only output I've ever needed. http://www.lexiconpro.com/product.php?i ... ger_images Turns out, there are two "line out" outputs on the back, but I've never used them, since my speakers only have one 1/8" socket for input.

These power conditioners that you linked to... do they function, more or less, as extra-grounded power strips? I've seen them at venues and practice spaces all the time, but never really knew what the different was between one of these and a standard surge protector. Sounds like it's likely to fix the issue. I'll probably get one for myself next payday.

[ken]

In addition to the "surge protection" you also get some filtering.

"An RFI/EMI interference filter works to prevent and suppress noise from fluorescent lights, certain dimmers, radio transmitters, and similar sources of electronic pollution from contaminating the AC line and from there, leaking into sensitive audio, video, or computer circuits. "

Ken

[AJOwens]

Turns out, there are two "line out" outputs on the back, but I've never used them, since my speakers only have one 1/8" socket for input.

As long as you're shopping, you should pick up the cable you need. Better level and impedance matching.

[JonPorobil]

Turns out, there are two "line out" outputs on the back, but I've never used them, since my speakers only have one 1/8" socket for input.

As long as you're shopping, you should pick up the cable you need. Better level and impedance matching.

What cable would that be? Everything in my setup is plugged in with the cable it was designed for (and in most cases, the cable it came with).

[Manhattan Glutton]

It sounds like you can probably get by with a 1/4"->1/8" connector. In fact, I bet you have some laying around from things you've bought like headphones, etc.

[AJOwens]

Turns out, there are two "line out" outputs on the back, but I've never used them, since my speakers only have one 1/8" socket for input.

As long as you're shopping, you should pick up the cable you need. Better level and impedance matching.

What cable would that be? Everything in my setup is plugged in with the cable it was designed for (and in most cases, the cable it came with).

Well, it depends on your speakers, but if they are powered (internally amplified) speakers, I suspect the 1/8" jack is meant to take a Line Out connection rather than a Headphones Out connection. The difference in the two outputs is that the Headphones Out is already amplified somewhat to drive speakers, and it's expecting a headphone-speaker impedance of around 50 ohms; while the Line Out has a lower voltage to drive the transistors in an intermediate amplifier, and usually expects around 600 ohms.

So you'd need a cable with two RCA plugs to a stereo 1/8 plug. In theory, you'll get less distortion and less noise. I can't swear you'll hear a difference, but anyway it's the right thing to do.

[Billy's Little Trip]

If there is any kind of X10 being used in your house, those things can happen. A ground filter will fix it, or change whatever the X10 is operating and change to a passive infrared remote instead.
Typical household X10 things would be a remote controlled ceiling fan, lights with dimmers, automated security lights, etc. Those things often use X10 technology.
X10 uses the common wire throughout your house electrical to send signals to receivers and relays.

If you are sure that you don't have anything as I mentioned in your house, a ground filter will still eliminate AM radio signals and probably the crackling sound. The only thing common between you and your neighbor is the ground.

[JonPorobil]

Well, it depends on your speakers, but if they are powered (internally amplified) speakers, I suspect the 1/8" jack is meant to take a Line Out connection rather than a Headphones Out connection. The difference in the two outputs is that the Headphones Out is already amplified somewhat to drive speakers, and it's expecting a headphone-speaker impedance of around 50 ohms; while the Line Out has a lower voltage to drive the transistors in an intermediate amplifier, and usually expects around 600 ohms.

So you'd need a cable with two RCA plugs to a stereo 1/8 plug. In theory, you'll get less distortion and less noise. I can't swear you'll hear a difference, but anyway it's the right thing to do.

That's bizarre. The "correct" usage is to take that 1/8" out from my speakers, convert it to RCA, then convert it back to 1/4" (and with a Y-cable, so it's in stereo), as opposed to simply connecting the like sockets with the appropriate jack size?

[roymond]

The issue is that the headphone out is too strong for the powered speakers (when you use the headphone jack from an iPod into a stereo, it'll distort like crazy if the iPod volume is all the way up. If you use a dock with the weird plug on the bottom, the volume control on the iPod doesn't affect anything and it doesn't distort - that's basically a line out. I know you're not complaining of distortion but it's the same concept). That's why you should use line out instead, which is assumed to be RCA. If it's not, then use the appropriate jacks for the line out, and on the other end of that cable is an 1/8 stereo jack for your speakers.

[Manhattan Glutton]

If each speaker has its own input, do what's common sense and just use 1/4"->1/8" adapter.

If the speakers are linked and one takes stereo input, you need some sort of Y cable. Like this I think: http://www.amazon.com/Live-Wire-TRS-Dua ... B001G7HDKQ

[JonPorobil]

Just for reference, the "Line Out" on the Lambda is two 1/4" phone sockets. Again, see: http://www.lexiconpro.com/product.php?i ... ger_images

So, in sum, here's what it sounds like you're asking me to do:

1.) Take a 1/4"-to-1/8" converter to get a 1/4" cable to plug into the 1/8" socket on the back of my subwoofer.
2.) Take that 1/4" cord and run it into the "Line Out" on the back of the Lambda.
BUT WAIT! There's TWO "Line Out"s on the back of the Lambda: one for each channel of audio. So...
3.) To connect it adequately, I'll need a Y-cable, or else perpetually miss half of the audio.

I'm concerned, because not only does this look inelegant, it's also going to flatten my audio. Even when I get two channels of audio, they're both feeding to the single stereo input on my subwoofer, so the signals will mix and come out in mono anyway.

And then... If I do all this, will it fix the A/C crackle problem?

It's starting to sound like I need a better set of studio monitors.

[AJOwens]

So you'd need a cable with two RCA plugs to a stereo 1/8 plug.

That's bizarre. The "correct" usage is to take that 1/8" out from my speakers, convert it to RCA, then convert it back to 1/4" (and with a Y-cable, so it's in stereo), as opposed to simply connecting the like sockets with the appropriate jack size?

Whoops, my bad -- I assumed the line outs were RCA. That's the thing, you never know. The reason your speakers have a 1/8" jack is that the manufacturer thought you would connect them to the Line Out on a typical PC card, which to save space uses a 1/8" jack. In that case, you would need a 1/8 to 1/8 stereo cable. On hi-fi equipment, Line Outs are usually RCA jacks, so if you were hooking up to a CD player, say, you'd need the RCA to 1/8" cable. And for what it's worth, my M-Audio PCI cards use RCA for the Line Outs. But the Lambda is using 1/4" jacks for the Line Out, probably to support connection to mixing board channels, so to connect to these speakers you need two mono 1/4" plugs to one 1/8" stereo plug. Which could be a little harder to find.

Those 1/4" jacks are probably balanced, by the way, so you could run them to balanced inputs on a mixer. For that you'd need two cables, each with a 1/4" stereo plug and an XLR connector. But at the moment that's too much information.

[Manhattan Glutton]

Yeeeeah that product I linked to above seems about right. I doubt it'll adequately address your problems here, though, but it's something you "should" do that won't cost "a lot" of money.

I'm still rooting for the better audio interface. Power conditioner second.