Inspiron E1505/6400 - external mic not recording properly

Question

Hi, I just purchased an Inspiron E1505 (6400) and would like to use it to record conferences/appointments using an external microphone. However, whenever I start a recording, it records well for 10-15 seconds or so, then the microphone gain drops abruptly and the input level falls to zero. Thereafter, the mic only picks up loud noises. When I listen to the recordings, it sounds fine for the first 10-15 seconds (with ambient noise audible too) but then it goes silent, and only loud sounds are heard, and even these are muffled & garbled. This is unacceptable for recording conferences, where many different voices (at different volumes) need to be picked up. I spent 2 hours on tech support with Dell tonight, and we tried several things-- adjusting the mic input level in the audio properties, turning on 'microphone boost,' disabling (and then re-installing) the SigmaTel audio drivers & HD Audio Codec, running a diagnostic test of the sound card, etc, but nothing seemed to work. I've had this problem with four different software programs (including the XP 'Sound Recorder') and three different microphones (Griffin iMic, Creative Labs, and a no-name cheapie from Radio Shack), so I don't think it's a software or microphone problem. I've searched the SigmaTel website to see if there's an incompatibility with these microphones, but I couldn't find anything. Any help would be greatly appreciated. Hopefully there's a fix available for the SigmaTel sound card, because this seems to be where the problem is. I've been using an HP laptop to record conferences & meetings for the past 2 years (with no problems) and would hate to have to go back to that machine.

Zoejaspar · Answer

Hi PJ1280,

Likewise I too have discovered this problem yesterday with my new 6400. I use Audtion 1.5 and find that the level meters will start recording at about -56db noise floor. Then after 20 second or so the noise floor level will drop to -120db. Its consistant with the signal output path FROM the sigmatel chip TO the DELL's internals going open circuit. The level will occasionally return with high level inputs.

My first thoughts when I heard it was a noise gate operatiing but with a very badly set threshold.

I am not looking forward to the DELL comunications but I fear its a faulty Sigmatel DSP IC on the DELL's main board.

Faulty equipmemt from Sigmatel. I will keep trying to find the problem in software but I fear its a faulty laptop.

ZJ

Naegling · Answer

I have the same thing happening to me.

I'm using a loaded E1505 to record letures using audacity software. I'm having the same gate problem you mentioned above. It will start recording fine, but about 15 minutes in starts to "gate" the speaker with very high attack and release threshholds.

Has anyone found a way around this? or prehaps better audio drivers?

Thanks,

Naeg

pj1280 · Answer

Thanks for the follow-up posts.

After talking with three different tech support reps, installing & uninstalling all the Sigmatel drivers I could find, and finally doing a System Restore (which still didn't solve the problem), Dell agreed to replace the computer for me. Should get the new one sometime this week.

Interestingly, I have a brand new Dimension 5150 using the same Sigmatel audio drivers (and the same sound card???), and recording works just fine. Maybe something in the design of the Inspiron motherboard (like what Zoejaspar suggested) is the culprit?

If the new machine doesn't work, I'm sending it back and going back to HP!

pj1280 · Answer

Just got my replacement computer, and have the SAME problem. Thus, the computer is essentially useless for recording lectures or conferences, because the sensitivity of the mic falls to near zero after 10-20 seconds. Anyone have a fix (updated driver, maybe?) before I send this machine back to Dell and ask for my money back?

Zoejaspar · Answer

Hi, My 6400 just had a new motherboard fitted and its still the same.   I have proven that the audio recording programs work fine using an Audio to USB converter.   I guess its a driver fault and we push to get that rectified.  I have a few USB adaptors for audio and typically much better audio quality anyway.   ZoeJaspar   Message Edited by Zoejaspar on 05-06-200605:33 PM

FaultyAudio · Answer

Have a new INSPIRON 6400 with the exactly same problem, same experience.   Had gone through the same scenario:  After a few hours marking around with Dell techies... Got a new motherboard... ... waiting for Dell call back in the future... near future... ... It's simple now, unless Dell has a new batch (either updated driver or hardware), all other technical support will be simply wasting time...   I figured the problem is no 'Mute' option on MIC while recording, while some sort noise/echo cancellation mechanism is action, at the same time, the AGC(auto-gain-control) is not well designed, surely MIC volume will die away...   Any other known Dell models with similar configuration got a working mic jack? It might be easier to exchange for another model than trying to fix it...   Dell definitely knows the issue by now.  Recall a whole batch? ... Forget it!

Zoejaspar · Answer

I have actually been told by a Dell technician that they now acknowlege the problem and they have their R&D working on it.  It should be a driver problem but we wait and see.   There is no AGC on either the mic or line input. The problem is based on the DSP algorithims as they work through the encoding of the level. You may have noticed it will occasionally drop out all recording for a second or two even while full audio level is going into the input. I initially just found it dropping out when then input level was low (even with gain levels set full).    Dell have said it will take a couple of weeks to get a reply from R&D.  .......??   Thank goodness for USB audio input.

SpideR W · Answer

I have noticed the exact same problem all of you have noticed. After a little digging in the registry, I've found a key labeled input_noisegate. Sounds promising, but whenever I set the ratio to 0 (effectively disabling the gate), it resets to the default value of 190. Does anyone have any insight on this one?

The full reg key is as follows:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4D36E96C-E325-11CE-BFC1-08002BE10318}\0005\Settings\filter\rear\Presets\_Initial\Capture\Input_Noisegate

I'd really like to get to the bottom of ths one...

Zoejaspar · Answer

Hello all on this thread. Dell have FIXED the varying recording level fault.  Its a bios update that has fixed mine.  It was not the A06 version. They sent me a beta version x25 and it fixed the recording bug immediately.   Keep in touch with Dell and see what they can do. New bios version may be on their site soon.   Zoe Jaspar

SpideR W · Answer

Wow thats good to hear! I'm glad they found the issue... hopefully the bios will be available to all soon!

Naegling · Answer

Sounds Great! Could someone post a link when it goes live?   Thanks, Brent

pj1280 · Answer

@Naegling wrote: Sounds Great! Could someone post a link when it goes live? Thanks, Brent Let me second that request!! It would be great to finally be able to use my microphone!!

Indiasun · Answer

Any updates on this one. I am cought in the same problem Thanks

pj1280 · Answer

I'm still having this problem, even after updating the latest audio card drivers and BIOS software (on 7/26/06).  I called Dell tech support, and the technician told me he's never heard of this problem!!!  (And he didn't seem to want to listen to the fact that several people have posted about it on the community forum.)  Basically, he wants to run through all the diagnostic tests, etc-- which I did, for about 30 minutes before I had to get back to work.  (And, no surprise-- everything checked out fine.)   If ANYONE out there has any suggestion (or can email me a BIOS version or that actually has fixed the problem), PLEASE let me know!!!!  Dell tech support is becoming useless, and Dell is rapidly losing my (admittedly puny) market share.   PJ

Indiasun · Answer

Hi pj1280

Join the club. I'm having the same problem, I'm just about ready to throw my Dell into sea, if only I could afford it. I've spoken to Dell technicalsupport many many many times and it appears all they are in terested in is political correctness. Everyone is polite and there is an overwhelming desire on the part of everyone I have spoken to , to be seen as extermely helpful but they are yet to solve a single problem. With this particular problem they haven't a clue what's happening and are not willing to research or experiment and keep going throught the absolutely non productive excercise of taking their customer through the steps from their manual. Any help would be greatly appreciated.

Thanks

Indiasun

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