Weird volume issue on PC

[beelzerob]

Nope. In fact, I've actually removed 3 PCI cards while I was at it reinstalling the system, so it's even trimmer now than it was. This is my CQC server, so I try not to ask it to do much else.

Here is one of the few scenarios I can think of that would explain the differences in sound. It's almost like I was somehow plugged into the back channel speaker output by mistake. So that some sounds that would play through front and rear channels equally would be perfect volume (the windows startup, login, logoff etc sounds). But other sounds would only be played through the front channels, which is why in the rear channel, I'd hear it reaallllly quiet.

It's *like* that as far as sound goes. But I'm NOT plugged into the wrong sound output, and I don't understand how my audio cable could be mimicing that effect.

 

[123]

... know WHERE the problem is... Somehow...it is the cable.
.. the speakers are connected through 2 cables, totalling probably 30 ft
....some sounds are still crystal clear loud, and other sounds are very very quiet.

...a pair of amplified speakers plugged directly into the sound channel.
...once it was all setup and ready to go, I switched the cables ... the sound has gone crazy again.

...I took them back to the basement, plugged them in directly, and they sound great.

...How can a cable possibly be consistently favoring certain sounds?

beezlerob,

I think I said "BWAH-HAH-HAH" after I read your post. I encountered the same problem a few months ago!

It wasn't clear to me, from your earlier posts, that you meant some frequencies were being suppressed whereas others were allowed to pass normally. My amplified speakers were driven through 50 feet of, in retrospect, under-sized wire and reproduced a narrow range of frequencies. Depending on the song, the effect was hilarious. Michael Buble's "Fever" sounded like he was singing out of tin can accompanied by a metronome. AC/DC's "Dirty Deeds Done Dirt Cheap" was especially good for cheap laughs ... the heavy guitar build-up leads to ... Johnson singing over a bad phone connection.

What wasn't funny was trying to find the cause of the problem! I thought it was a bad connection because it seemed like, with some jiggling of the connectors, I could get it to work sometimes ... but not always. Finally it never worked properly and all of our music sounded like synthesized soundtracks with tinny vocals.

I cut the connectors off the undersized cable. I replaced the wire with CAT6. I soldered the connectors using several pairs per connection. Problem solved.

My theory is that the undersized wire had just the right capacitance and inductance to act like a band-pass filter and let some frequencies through and suppress others. Why it worked properly at some times but not others remains a mystery to me.

 

[pete_c]

I've also noticed that sometimes the thin audio cable ends gets stressed a bit causing intermitting audio. I cut them and solder new ends using heat shrink tape. It would be difficult but if you could say send a song to the speakers and 'jiggle' the end cable into the PC and see if that changes anything. I noticed that the new audio inputs also sense whether you have inputs or outputs plugged in and configure themselves.

 

[beelzerob]

Ya, I've been laughing too 123, but it's been that maniacal "I must be going crazy" laugh. :hesaid:

I don't have much doubt you're right. It's a very weak signal, and it's going a long way. I'm hoping the USB speakers will meet the need, or else I'll have to make my own cable, and might have to pull some new wires. Ick.

Thanks for the sanity though. That explanation makes the most sense, and I'm willing to just believe that's it, than continue to try and reason it out.

 

[beelzerob]

1 pair of Logitech USB speakers later, my "weird volume issue" is finally solved. Man, was that a hair-puller. If the sound hadn't worked from the very beginning, I could have quickly deduced it was the audio cable. But instead, it's like a year later, and it suddenly stops working. Grrrrr.

But I'm pleased with these new speakers. Compact, and sound good enough for what I need.

I put in a powered hub just in case it needs the power, but I also tried it without the powered hub, and they appeared to work just fine. Do I really need the powered hub here, or can I just use the power coming on the USB cable from the PC (which is probably about 20 ft long)?

 

[electron]

Windows would complain if it wasn't able to provide enough power to the USB port. You can also check the current usage in device manager. The thing with most USB speakers is that they act as their own soundcard, so you are bypassing the problem, it isn't fixed.

 

[beelzerob]

Well, the problem was undeniably the audio cable, so the problem *is* fixed, by bypassing it.

I may keep the hub there for now, if I can hide it well behind the touch screen. I have the speakers as well as the wireless receiver there for the keyboard/mouse, and this way we can plug USB drives into it too. But I'll look in windows for the current usage, but what will that tell me? I don't know what the max should be.....

 

[electron]

USB spec is 500mA maximum. If you use more than what the board can deliver (some cheaper motherboards don't follow the specs), you'll get a balloon nitrification in your traybar area complaining about overloading the port.

 

[beelzerob]

Neato. I'm curious just what difference plugging in my hub power makes on the power consumption from the PC. If I can get away without having yet 1 more wall wart behind the touchscreen, I'd be happy.

I can't seem to find where that power consumption value is...I looked on the device manager, for the USB hubs and such. It's a work computer, so maybe they hide that info from employees....

 

[pete_c]

You can just keep plugging in stuff until it shuts off your USB port. I added a USB hub to my wifes computer because it currently is powering her:

1 - speakers
2 - keyboard
3 - mouse
4 - printer



Here's what it looks like:

 

[beelzerob]

Excellent, found it. Thanks!