Compal HGL30 microphone

Is the terrible quality of the Compal's built in microphone attributed to a lot of EM interference from the screen? Or is it just a bad quality microphone?

Or is it not enough power to the microphone? If thats the case thats pretty horrible design I would think, since the mic jack clearly outputs enough power for most conventional microphones.

 

The mic built into most notebooks I think suffers from being muffled under the chassis near components that put off EM or audible noise, or both.. I hate to say it but generally speaking they are probably just there "in-case", and they figure anyone really using a mic will use an external headset or desktop model.

I've found that they generally have OK quality, but suffer from lacking volume.

 

I am getting fed up with carrying around a micromaphone with me everywhere, having to plug it in and such, and then have constant questions: "you have a built in microphone, why don't you use it?" etc etc.

Dammit. I was hoping the microphone part in particular would be of cruddy quality, then I could pull apart the screen, cut the built in one off and put a better one on from a cruddy microphone I have. I have no idea whether the process will be as cut and dry as that though (barring some very fine soldering). Are there any pictures or anything that show the screen without any plastic? Or a assembly/disassembly guide (not the HEL80 video).

 

Love the dialup speedtest

As for your concern about carrying stuff.. if you just got a headset unit you could argue that the quality is much better, and it doesn't matter how you sit at your notebook because it won't change the quality...

I haven't seen any dissasemble guides anywhere for the upper half posted on here, but I'd imagine it won't be to hard to get at. I'll bet it just run with some red and black wire all the way up through the lid (assuming it's like many notebooks), however there might be a small pcb it's attached to for the camera assembly.

 

Thats a nice site, speedtest, it took me 10 minutes to do the test though
oh man I hope theres no pcb attached... and its likely theres wire? I was hoping that, failing replacing the microphone, I could put plastic sheathed wires in to reduce the EMI caused from everything.

Jeez maybe at this point I should try snaking a wire from the input jack, through the bottom part of the chassis, up the back of the screen (on the outside of the plastic) and punch a hole through the small holes at the top of the screen. It would certainly give the laptop a... rustic look.

 

I'm only making a guess at the PCB idea, because it would make sense from a hardware consolidation point of view. Perhaps the camera itself is causing the interference you are talking about?

Have you looked up the thread on the HEL80 noise? I did alot of posting over there and remember a few people saying that disabling their camera helped...

I always have all hardware I don't use disabled out of old habit to conserve addressing locations, but I'm strange like that.

 

not to mention that it slightly speeds up your boot time disabling hardware... disabling the camera kind of defeats the use of this laptop in msn though.. still i'll giver a go with Goldwave and see if the distortion goes down at all. I suppose at this point I'm just being picky as hell, but even still, having a mic thats built in and actually works would be really nice, since the camera ain't too shabby... albeit a bit picky on lighting conditions, but thats for another thread

EDIT: Tried disabling the camera.. no difference. Also tried using the CD drive, putting the brightness up and down, and disabling/reenabling the touchpad, but there was no difference. However, making the microphone input noise come out of my headphones seems to increase the noise by roughly 10db. Muting all sound returns it to normal. Interesting....

I would have figured the voltage going through the monitor (raising and lowing the brightness) would have made some difference, but it didn't. I also tried using the power settings and seeing if there would be a change if the screen was off completely, but no dice.

Is EMI based on the amount of power going through a component? Or does the screen have some current going through it as long as the power to the machine is on?

Yeah I went though that entire thread a few weeks ago, the gist of it was people suggested either doing some funky stuff to the wiring (putting something on it.. either way it was way too much effort), using a headphone amp, or the one thing you suggested, wrapping your hard drive in tin foil (tried that, but the metal cage thats already there does the same job)

 

EMI is created by anything of mass that has moving molecules (anything of mass has a magnetic pull, and anything with moving molecules puts off a small amount of energy)... but effectively any closed circuit will be like an amplifier so even in an off state there will be 'some' EMI from the device, even if it's just residual inside the components (capacitors, resistors, etc...)

Not sure what else to tell ya on a way to fix it.. I could think of about 3 dozen ways to work around it.. but you seem to already have your own gears cranking on that end..

This "bad audio" from on board chipsets is as old as the term onboard... but it seems to be improving with each new generation.

 

Hmm so only if the electrical parts are totally devoid of charge... dang, that's not gonna happen...

The wires that go to the microphones (theres 2 shown in the pictures... odd) snake behind the monitor inside the plastic housing via plastic sheathed wires.
Theres no PCB for the camera and microphone though, only the camera (thank god).

Unfortunately the back of the screen looks like it has a tin foil like material that probably shields any EMI from hitting the wire, so I guess the interference is caused somewhere under the keyboard, or wherever those wires connect to the motherboard.

I was combing over pictures from the disassembly steps (it took me all night to download it. 75 MB ) and found the microphone cable. As I suspected, it snakes throughout the laptop (out the bottom of the screen, across the motherboard, and connects near the touch pad). I guess I'll break out some trusty tin of foil and see if it helps... Or I could try soldering the cord to the audio input jack. Since there doesn't seem to be any interference from it. I don't use the jack, so using the built in microphone only would be fine by me.

Actually wait, if I add a ground to the circuit, will that remove the EMI?

Actually though, before I do that, where can I get double sided tape? Might as well do the keyboard fix while I'm at it.

 

Paint section in most superstores (like Walmart / Fred Meyer) normally has a "tape rack" that would have it.

Try disconnecting the mic (I'm assuming it's a jack/header style, and not sautered on) and snagging an old mic that you can cut up to make a test connection using the header..

I'm assuming the two wires are positive and negative, so a ground might help, if you are careful you could create an extra ground on the header without fully unplugging the built-in mic. (It order to get the current to travel down to the mic, you have to create a closed circuit, thick a vacuum).

That aluminum sheet is for EMI cancelling just as you guessed.

I don't suppose the audio jacks are connected to the motherboard with a header eh? Again, would make patching into the audio jacks easier.

 

Another thing.. you never described your problem.. Are you getting alot of recording interference? Or are you getting that lovely "wowww woowwww" repeating sound?

 

An arse load of static, on the order of 30-40 decibels. I want to remove the static so that I can talk and show myself to some of my friends via MSN with out looking like a cyborg with a headset. as well when I go back to school in September, it will be helpful to not have to lug a microphone around. Also, this will help others who own this notebook by getting a microphone that they paid for.

I'll try plugging a crappy one in if shielding dosen't help, thanks!

 

I've took the challenge and replaced the original 50cm internal unshielded microphone cable with a shielded one. The sound is now much better and the built-in microphone can now be used for the purpose I had in mind when I purchased this notebook about a year ago - Skype calling.
The microphone input of the internal soundcard itself is very noisy as can be found out by listening to the mic input with the microphone connector detached, but with the shielded cable in place the volume of voice is finally above the noise level. Together with Acoustic Echo Cancellation turned on, the skype experience is quite good.
While I was at it, I've replaced the internal electret microphone with a slightly more sensitive one, but it is not necessary, the difference is not that big.
To replace the cable, one needs to remove the keyboard and disassemble the housing of the LCD display - 10 screws altogether. Only the keyboard connector needs to be disconnected.

 

Nice! Since my laptop's warranty is now apparently void (milestonepc.com doesn't cover you after you add thermal grease...) I'll give that a shot. Where did you acquire the shielded cable from?

 

My compal mics work just fine, however one is balck and the other on is more of a metalic color, I'm wondering if the dark color comes from a protective material or it's just paint.