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Defect in MBA2012? GPU? MBA/Thunderbolt, sound degradation! Can someone help test??

So I tested this with a 5ghz wifi connection, and here is what happened:

- The distortion buildup was MUCH slower, for a while I thought maybe that was the solution.

- When the distortion came back, it was a totally different tone. at 2.5ghz, it was sort of crackly and poppy, at 5ghz it was more of a white-noise sound.


I am wondering if I should wrap the thunderbolt cable in tinfoil or something? Is there a way to shield it? What about switching channels? Right now my router is on channel 11. Or is this a cable thing. I think I will try the tinfoil thing just to try it out haha. Or what about like screen door mesh, if it is metal?

Also...... this doesn't seem like something that can be fixed via software, right? It would have to be new cables for the monitors, right?
 
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Sean, yes, I would try aluminum foil first to see what happens. Ideally, a copper shield over the cable grounded on both ends would be the best.

Popping and cracking is a sign of in-band strong signal overloading. White noise is a sign of out-of-band strong local signal desensitizing the receiver.

On the 2.4Ghz band, try changing the channel to the lower end (Ch1-3). When we tested PCIE, it wiped out Ch. 13, which is the high-end of the 2.4GHz band. Also, try changing channels in the 5GHz band and see if the character of the noise changes.

Hard to say just yet if this is a software issue. It could be a shielding issue within the laptop, or perhaps a new part that requires more shielding. It would be interesting to know if it was changed between 2011 and 2012. Maybe iFixit would know?
 
Well, it doesn't happen on my 2011 MBP. Or the 2011 MBA as the OP mentioned, right? It's obviously an MBA issue... or we would have heard about it already...
 
I watched two hours of tv the other day and played some games off of my tb connection with no issue.
 
asting said:
I watched two hours of tv the other day and played some games off of my tb connection with no issue.
Click to expand...

were you on WiFi? can you post what frequency you are on, and the channels you are on?

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calvol said:
Sean, yes, I would try aluminum foil first to see what happens. Ideally, a copper shield over the cable grounded on both ends would be the best.

Popping and cracking is a sign of in-band strong signal overloading. White noise is a sign of out-of-band strong local signal desensitizing the receiver.

On the 2.4Ghz band, try changing the channel to the lower end (Ch1-3). When we tested PCIE, it wiped out Ch. 13, which is the high-end of the 2.4GHz band. Also, try changing channels in the 5GHz band and see if the character of the noise changes.

Hard to say just yet if this is a software issue. It could be a shielding issue within the laptop, or perhaps a new part that requires more shielding. It would be interesting to know if it was changed between 2011 and 2012. Maybe iFixit would know?
Click to expand...

How can I get flexible copper? Can I go to home depot and get some copper based wire and wrap it around? Lol what if I test it with a copper pipe with the cable strung through it? I'll see what home depot has and if there's a way to get copper insulation around it. Maybe I can slice a cable open longways and then take out the actual wire and keep the shielding, and wrap that around the TB cable.

??
 
I'm curious... Is this a problem for both 11" and 13" 2012 MacBook Airs? OP, what size MBA do you have?
 
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I would see if Radio Shack has some tubular copper braid. The challenge will be finding some large enough to fit over the connectors. In that case, you may have to get some 1/4" braid, cut it lengthwise, then slip it over the cable, then resolder it. In either case, the shield should be grounded on each end to the computer and display chassis with a groundstrap. You might first try this with aluminum foil, and make sure it's grounded at both ends. If there is substantive change, then go the extra effort to make a copper-shielded TB cable.

The other thought I just had is, that the WiFi may be interfering with the TB chip on the cable, so I would try shielding the ends of the cable as well.

http://products.conwire.com/viewite...bular-tinned-copper-braid-qq-b-575?&forward=1
 
Photios said:
I'm curious... Is this a problem for both 11" and 13" 2012 MacBook Airs? OP, what size MBA do you have?
Click to expand...

I've tried 2 2012 11".

(the 2011 11" had no issues)



calvol said:
I would see if Radio Shack has some tubular copper braid. The challenge will be finding some large enough to fit over the connectors. In that case, you may have to get some 1/4" braid, cut it lengthwise, then slip it over the cable, then resolder it. In either case, the shield should be grounded on each end to the computer and display chassis with a groundstrap. You might first try this with aluminum foil, and make sure it's grounded at both ends. If there is substantive change, then go the extra effort to make a copper-shielded TB cable.

The other thought I just had is, that the WiFi may be interfering with the TB chip on the cable, so I would try shielding the ends of the cable as well.

http://products.conwire.com/viewite...bular-tinned-copper-braid-qq-b-575?&forward=1
Click to expand...

I will give this all a try. I am not sure how to ground stuff though. Just get some wire and connect it to something grounded like the metal legs of my table? Will it work at all without grounding?

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A guitar website suggested this for em shielding. A little copper tape I could make a sleeve with easily, wrap it in rubber?

http://www.homedepot.com/h_d1/R-100...62157&storeId=10051&langId=-1&catalogId=10053

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Also - I was having a hard time replicating this on my work network, but I just checked and our network here is 5ghz, so I might not have been able to trigger it, not to mention that we're using a big enterprise class wireless setup, which may be different than my consumer router.

Here at work I am on 5ghz channel 36.
 
How do you view that info under OSX? Forgive me, this is the first mac I've owned (and the models I was very familiar with were 6+yrs old).
EDIT: figured it out. To those wondering, hold down option while clicking the wireless icon. I was on channel 6 at 2.4ghz. I was about 8 feet from the router at that point, so I'm not sure if that comes into play.
 
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asting said:
How do you view that info under OSX? Forgive me, this is the first mac I've owned (and the models I was very familiar with were 6+yrs old).
EDIT: figured it out. To those wondering, hold down option while clicking the wireless icon. I was on channel 6 at 2.4ghz. I was about 8 feet from the router at that point, so I'm not sure if that comes into play.
Click to expand...

The frequency and channel are fixed values for whatever your router is set, interference or distance won't change those. There are other values in there that measure that (rssi, transmit rate, etc etc)

I'm gonna re-run all my tests on different channels and then do it all again with aluminum and copper shields.
 
Sean Dempsey said:
The frequency and channel are fixed values for whatever your router is set, interference or distance won't change those. There are other values in there that measure that (rssi, transmit rate, etc etc)

I'm gonna re-run all my tests on different channels and then do it all again with aluminum and copper shields.
Click to expand...

I understand that they're typically static values with a router. I wasn't suggesting that they would change when I'm further away (although doesn't it switch from 5ghz to 2.4ghz as the range drops off?). Instead, I was saying that maybe the interference is only an issue at long range, not the short range I was at (or perhaps that would exacerbate the problem). I'm not technically incapable, just not used to OSX.
 
asting said:
I understand that they're typically static values with a router. I wasn't suggesting that they would change when I'm further away (although doesn't it switch from 5ghz to 2.4ghz as the range drops off?). Instead, I was saying that maybe the interference is only an issue at long range, not the short range I was at (or perhaps that would exacerbate the problem). I'm not technically incapable, just not used to OSX.
Click to expand...

I am not sure if distance from the router is a factor, that's an interesting factor. I wondered if it's not the signal from the router, but the proximity of the TB cable to the laptop wifi antenna.
 
WiFi tx power out is static, i.e. it is set at a certain level at the router and client, so distance from the router would not be a factor. (In GSM phones, tx power is dynamic, depending on distance from the cell tower).

The $1M question is, what has changed in the Air between 2011 and 2012 with respect to grounding/shielding? Is it the shielding of the WiFi card, grounding of the TB socket, or a change in the logic board layout?
 
Has this come up for anyone else? I am so used to not being able to do sound/video on my machine, I had forgotten about this until I was trying to skype video. Sure enough, it's all back and my sound is unusable.

I went the rounds with Apple on this before, going so far as to replace the whole computer and monitor.

It's really ********. An unfixable, unusable aspect of a computer. I don't get how this doesn't come up more often, it's consistently reproducible, and I've done it with 2 computers on 2 different TBD's.

Since posting this originally, I have:

1. Changed houses
2. Changed routers (linksys to Airporte eXtreme)
3. Went from wifi, to wired ethernet, back to wifi (which I can't change now, no cables)
4. Installed Mountain Lion and all updates

I want to get a 15" Retina on the next refresh, but is this just going to happen again? It's silly that if I want to use apple computers, I have to forgo sound, video, a TBD and wifi at the same time.

Edit: Apparently not, someone from just April 13 is having the issue with a Retina MBP too: https://discussions.apple.com/thread/4051858?start=180&tstart=0
 
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garbled sound + usb problems

Issue persists as of July, 2013. Running Air, OS X 10.8.4 and Thunderbolt display with connected peripherals (keyboard, mouse, printer). Steps to replicate reliably:

1. Start Skype > Preferences > Audio/Video to see the camera. Start a music source (Spotify in my case). Drag the preference pane to Tunderbolt to see the video. Leave on.

2. Admire yourself in the camera. Pretend to type and listen to the music for 3-5 minutes.

Symptoms: Audio slowly degrades with static, disappearing altogether. The usb keyboard disconnects intermittently. Problems not affected by wifi / wired connection.



100% replication rate on my system
 
soyiuz said:
Issue persists as of July, 2013. Running Air, OS X 10.8.4 and Thunderbolt display with connected peripherals (keyboard, mouse, printer). Steps to replicate reliably:

1. Start Skype > Preferences > Audio/Video to see the camera. Start a music source (Spotify in my case). Drag the preference pane to Tunderbolt to see the video. Leave on.

2. Admire yourself in the camera. Pretend to type and listen to the music for 3-5 minutes.

Symptoms: Audio slowly degrades with static, disappearing altogether. The usb keyboard disconnects intermittently. Problems not affected by wifi / wired connection.



100% replication rate on my system
Click to expand...

Same. Probably wont be fixed now that we are a generation out.
 
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