Sound Mixer problem on Acer Travelmate 2492 with Realtek HD Audio

[martinu]

This is a copy of my contribution to another thread No Sound From Headphone Jack With Realtek Hd Audio Device http://www.softwaretipsandtricks.com...io-device.html. I've raised it as a new thread to increase the chance of people seeing it, because although it's related to that symptom, it is actually a symptom that has not been described yet.

I'm having two problems with the Reatek HD Audio soundcard in my new Acer 2942 WMLi laptop.

First of all, although the sound from the mike or the line in records perfectly well, instant messenger and chat programs such as Paltalk or MSN have appalling sound quality - very distorted and mushy. This is evident even in local "sound test" menus, and so is not a networking/internet issue - it's to do with the feed of data from the sound card to Paltalk etc.

Secondly, at a random time after talking on Paltalk, the "Stereo mix" input to the recording mixer stops working. Normally anything that can be heard through the speakers (wave, mike etc) becomes available to be recorded or to be output through Paltalk or MSN Messenger. However this input often suddenly fails: even though sound can be heard, it is no longer recordable. Mike and line-in inputs still work fine. Only a reboot cures the problem.

Looks as if some software packages knacker the sound card's capabilities.

It's not just my PC. A friend with a 2942 has similar problems.

(By the way, does anyone know why Acer build their laptops with the hard disks formatted as FAT32 rather than NTFS? Has anyone converted from FAT32 to NTFS using the DOS "convert c: /fs:ntfs" command? Does everything work OK, or should I avoid doing it?)

[martinu]

I've just tried updating the drivers to the latest version (1.54 rather than 1.41 which is what is supplied with the PC) and this cures some problems but creates other new ones

With the 1.41 set (listed in Device Manager as 5.10.00.5273):

- the mixer intermittently loses the Stereo Mix input and the CD input on the Recording volume control: you can select them but nothing is recorded; line-in and mic still work

- the mike, as heard live through the headphones, only plays through the left channel; however it records on both channels (in mono)


With the 1.54 set (listed in Device Manager as 5.10.00.5345):

- the mixer always fails to record from Stereo Mix or CD

- the mike plays through both channels and records in stereo (although I only have a mono mike, I've proved this by connecting an external lead and touching first the left then the right pin of the phonos at the far end of the lead!)


In both cases, the mike signal is very noisy: having recorded noise in CoolEdit, it looks like pink noise - louder at lower frequencies than at high frequencies. With either the internal or an external mike, I'm getting noise at about -24 dB with sound peaking at about -6 dB, so signal-to-noise of only 18 dB. Turning mike boost on and off only affects the overall volume - the ratio of signal to noise stays about the same.


Sadly, Realtek's site only has the 1.54 drivers, both as offered on the web page and by looking behind the scenes on the FTP site, so I can't try other builds between 1.54 and 1.41


Anyone got any suggestions? I bought the laptop partly because it's one of the comparatively few that has a line in socket as well as the normal mike in and line/headphones out, because I'll be using it to record from records, VHS, audio cassette etc from time to time. I wonder if I should have gone for another make such as Toshiba or HP.


Apart from these infuriating sound problems, my Acer is brilliant - and it's got a proper matt screen rather than one of these toy glossy screens which reflect yourself, the room lights and the window panes: I chose that model very carefully for that reason!

[martinu]

Further testing has established that the sound card produces a lot of distortion and metallic sound quality when recording at lower bit rates.

I've just done test recordings from my mike using CoolEdit.

- At 44 kHz sample rate, the quality is good, though there's rather a lot of background hiss

- At 22 kHz, there's some metallic quality

- At 11 and 8 kHz, the sound is raspy and muffled: I sound as if I have a lisp!

Taking the original 44 kHz recording and downsampling it in CoolEdit to 22, 11 or 8 shows the difference: obviously the lower sample rates have their higher frequencies removed, but they are free of distortion compared with the versions which were originally recorded at the same rate.

The reason that I've experienced poor quality sound in PalTalk is probably that it samples at 8 or 11 kHz.

There's evidently something seriously wrong with either the hardware or the drivers. I've raised a call with Acer but not had any reply yet. I'll keep you posted.