Help please: Clipping Conundrum

[jordanp]

Hey folks,

I've been a big fan of Audacity for ages, and just "upgraded" from a nice XP laptop to a nice Vista laptop. I am now, however, learning all the headaches behind media-handling on Vista machines.

So, I installed Audacity, and then jumped through all sorts of hoops to try to get my sound card to let me do "Stereo Mix" recording (it's Realtek High Definition Audio on an HP dv9700 laptop). I was told it couldn't be done, and for some time had given up that I'd never get Audacity to be able to read any audio signal out of the card. But then I saw some new driver had come out and installed it. That only made things worse (it would always play all sound through built in speakers, and not recognize a line-out). I had an "oh shit" moment, did a quick system restore, and not only did it get rid of the problems associated with the new drivers... but suddenly I was able to get Audacity to pick up signal from the Stereo Mixer.

So, that's all the backstory. Now the problem is that when I do record audio, I'm getting serious clipping on bass. The original sound is great on my speakers, but playing back what I've recorded on Audacity gives me awful, awful clipping whenever the bass kicks in on a track. Also, the playback from Audacity is a whole lot louder than the original sound.

Things I've already tried:

I've tried this in both Stable and Beta Audacity, same problem exactly.
Turn down the input level on Audacity (dragged the slider on the microphone symbol down to 50%). No change.
Turn down the level of the recording device (right click on the audio symbol in the taskbar > Recording Devices > Stereo Mix > Properties > Levels tab > set to 50%). No change. Though whenever I do this, it seems to reset to 100% immediately after I say Apply or OK.
Switch between using Stereo Mix and MS Sound Mapper as source, no change.

So, somewhere between my sound card and Audacity, and Sound Mapper and Audacity, something is going very much awry. I have the same problem if I use Vista's built in Sound Recorder - the WMA's it produces are great, as long as there's no bass - if there's bass I get exactly the same problem. That suggests to me that this is a sound card issue. Anyone have any insights on what I can do to get this clipping to stop happening? I know this isn't a high-quality sound card, but I just can't believe that this is the best my $1500 system can give me for sound recording.

I'm not recording anything fancy, just streaming audio, audio playing from a file already on my computer, etc. Like I said, the sound is absolutely flawless as long as there's no bass, but as soon as bass hits, all the sound gets pretty awfully distorted.

I'd really appreciate any words of wisdom on how to resolve this, thanks folks. With FairUse4WM dead for Vista, I'm pretty frustrated about the abridgment of fair use rights already... finding a way to at least make it possible to record streaming audio, Skype calls, etc., would be a major boost to my sanity.

[jan.kolar]

(I cannot find a message I wrote you before..., so once again.)

How high is your wave in Audacity - are the peaks going say to 0.5
or is much of sound going to 1 ?

If you change the output level in your program (Windows Media Player),
what happens, does the level in Audacity change?

(May you changed latency setting from default 100ms to something like 1000 ms
- then be patient, it takes 1 s to se any change.)


1. To make sure it not caused by limits of some (local) power source,
try to make your internall speakers off and do not use passive external speaker nor headphones.
I would do the trick by plugin into the line-out socket a jack that is 'connected to nothing'
I do not hear anythink; do a record in audacity and check its quality.

3. I realized in Vista RealTek driver, 50 % means -6dB, which is almost no change.
They use linear scale instad of logarithmic.
Try 10% or less.
By the way, I think that mic is irrelevant and should be not select or switched off.
Otherwise you would record sourounding sounds...

If mic means "input" (possible... I do not know Vista), check also mic boost scrolball
and you recording from line.
(set +0, not +20, +40)

by the way, what happens if you do record line-in ?
(you can loop line-out to line-in by a jack-jack cabel)

2. In XP I would try to change the level of Wawe. I have no deeper knowledge about Vista,
but if there is not Wawe, there will be ways to lower output of separate programs individually?

3. and a crazy idea, looking on your wave in Audacity, is there any DC offset?

[jordanp]

Jan,

Thanks for your PM, it proved very helpful. I have a great deal of frustration with the way Vista/my hardware is interacting and handling audio, but per your suggestion, I set the input level down to .1, and then used Audacity's amplify effect after recording, and that seemed to do the trick. Thanks. I wish I didn't have this headache that didn't exist for me with my old machine, but I guess such is life.

As a note to anyone who found this post through a search for similar issues or whatever, if you're using an HP laptop with Realtek Audio as the sound driver, DO NOT get the sound driver update off of HP's website - it removes the potential for a stereo mix altogether, and meant I had to do some messy system restore stuff to get it back.

[jan.kolar]

<< I set the input level down to .1, and then used Audacity's amplify effect after recording, and that seemed to do >>
OK, but possibly the background noise would be to high, try out and see.

half means -6dB (approximately)
That is
50% = -6dB
25% = -12dB
12% = -18dB
6% = -24dB
3% = -30dB
and so on ((but probably not precise at all below 6%))

[kozikowski]

We cringe every time we see audio systems measured in percent. 50% video gives you about half-brightness on the screen, but 50% audio is barely noticeable. Half volume to your ears is about -18 dB or, from Kolar above, 12%.

He only took his list down to -30dB, but your ears are still working down to -45dB or -50dB.

http://kozco.com/tech/audacity/Audacity1_full.jpg

That's why the sound meters in that picture go down to -60dB. That's about the limit of human hearing--and if you are a young woman, you can go even further.

Koz