Analog output has suddenly turned nasty...

Thikasabrik · Jun 15, 2004, 03:51 PM

Since the RMAA tests I performed on my Audigy 2 with the Kx drivers, the analog outputs (both front and rear) have started exhibiting a strange problem - the left channel has a much higher level of background noise than the right. This can be seen by checking the IO levels using RMAA. With the analog loopback disconnected, both channels show the same low level background noise, but as soon as the cable is plugged into the analog output, even with the output volume muted, the left channel shows noise at around -100 dB rather than the -120 dB of the right channel. This prevents RMAA from accepting the levels as reasonable. If i unbalance the output volume to get the levels right, high distortion is detected in the left channel. Is my nearly-new Audigy 2 fried? Has anyone seen this before? Could it be a software problem?

I have tested the inputs seperately by using the ADC in my Megaworks speakers combined with their handy headphone socket (spdif > speakers > headphone output > line-in) - no such problems. Btw, the 24/48 loopback through the megaworks seems to produce the best RMAA result I can get through the Megaworks at 48khz. Crosstalk is slightly worse than 16 bit through wave 4/5 but the rest of the results are better.

Here it is...

Frequency response (from 40 Hz to 15 kHz), dB: +0.06, -0.46 Good
Noise level, dB (A): -99.5 Excellent
Dynamic range, dB (A): 95.8 Excellent
THD, %: 0.011 Good
IMD, %: 0.011 Very good
Stereo crosstalk, dB: -87.9 Excellent

Doomsayer · Jun 15, 2004, 05:57 PM

Your analog cable would be my first suspicion, especially since the problem happens with both front and rear outputs.

Thikasabrik · Jun 16, 2004, 05:58 AM

I should have mentioned that I'd tried two different cables - I'll try another maybe, but I don't think it's that. Also, I used the same cable to link the headphone out of the megaworks to the input, so it does not sem to be a problem.

**dj_stick** · Jun 16, 2004, 06:00 AM

have you reduced the volume in the mixer at all?

Thikasabrik · Jun 16, 2004, 06:56 AM

Yes, I've fiddled with all the levels, input and output, while the IO level check on RMAA was loaded - so watching the effects on the graphs. No matter what I seem to do (apart from unbalancing the volume to increase the right channel volume) the left channel has the noise. Also, distortion is present at higher volume levels, that is very audible if the analog output is connected to speakers during the RMAA level check. This was present before this strange noise on left channel though.

**dj_stick** · Jun 16, 2004, 07:04 AM

do you have the default DSP?

Thikasabrik · Jun 16, 2004, 07:18 AM

Yes, I have the default, and I have even tried bypassing things like the Equalizer, and various surrounder settings. If I remember correctly, even when sound was coming out of only the rear output, there was still this noise on the left channel of the front output. I'd have to check again to be sure. I have tried using the waveHQ path as well as the standard path - both show this noise.

Doomsayer · Jun 16, 2004, 07:21 AM

That's strange. Try clearing the DSP and connecting Wave 0/1 directly to the Line Out on the Epilog.

Thikasabrik · Jun 17, 2004, 01:54 PM

I just tried a DSP setup with only FXBus and epilog: Wave 4/5 direct to Analog Front Output. Here are some screenshots...

Output muted
Output unmuted
Output at max

All three have gain set at 0. Feel free to recoil in disgust, or whatever.

TravelRec. · Jun 18, 2004, 03:01 AM

Hmm... very strange... not possible under normal conditions...

Confused

Try to check the digital connections via loopback (SPDIF out / SPDIF in), if possible. Try to use LeMury´s ProFx too.

Greetings!

TravelRec.

Thikasabrik · Jun 18, 2004, 07:27 AM

Okay - SPDIF, as I've said, doesn't seem to be affected, having tried digital to analog loopback through my megaworks speakers. This also eliminates the inputs as the problem. I have done a further test that confirms to me that this is duff hardware. Here is what I mean...

RMAA under Wine in Linux, using OSS emulation by ALSA driver.

That the problem is also present under a different OS using a completely different driver is pretty damning. I guess I'll be sending that sucker back to CL.

bennetng · Jun 18, 2004, 08:40 AM

You may have lossensd your soundcard because of repeated action of plugging cable. I also have similar experience. Try to re-plug your card into the PCI slot.

Thikasabrik · Jun 18, 2004, 02:03 PM

Nope - no good I'm afraid. Still the same. It musta got fried somehow.. Just out of interest, are there any other Audigy 2 owners who see distortion with the analog ouputs at maximum volume?

**dj_stick** · Jun 18, 2004, 04:36 PM

um i am pretty sure if you have the master output at max AND an eq, such as increased bass, yuo will induce clipping and distortion

StArSeEd · Jun 18, 2004, 07:15 PM

Quote:

Originally posted by Thikasabrik
Just out of interest, are there any other Audigy 2 owners who see distortion with the analog ouputs at maximum volume?

Me.. Audigy 2 ZS Platinum (SB0350): the analog output seems like it's a few dB's high and distorted, kinda like the DAC is being overdriven just a bit.. I've definitely been hearing clipping distortion on things which do not clip since switching from my SBLive! 5.1 Platinum. No EQ's in effect, default DSP settings, etc, etc.

**dj_stick** · Jun 18, 2004, 07:28 PM

on the school computer… the mixer's peak metre detects no clipping what so ever, yet when fed directly to the live level tape input of a hardware mixer, the mixer shows clipped level of upto +10 or 20dB, i believe this is due to internal noise from the computer affecting the ADC/DAC chips and perhaps the cables aswell. Also check if you have a clean power outlet from the wall

Doomsayer · Jun 18, 2004, 07:36 PM

Well, if there's something affecting the signal after the DSP, and boosting it by 20db, all you should hear from your line out is some mega distortion. It's also unlikely a kX-specific bug. I can only suggest trying the card in another PC to try to isolate any hardware problems there might be.

Thikasabrik · Jun 19, 2004, 07:10 AM

Quote:

Originally posted by dj_stick
um i am pretty sure if you have the master output at max AND an eq, such as increased bass, yuo will induce clipping and distortion

Certainly this is true - I meant without any other processing. My Live Player 5.1 gives a good signal with the analog output at maximum volume, and the Audigy 2 does not.

As for interference from the pc, this may be the problem, but since it only started to happen recently I am not certain. Maybe I'll try it in another one some time.

**dj_stick** · Jun 19, 2004, 07:11 AM

try the card in another computer if possible

Thikasabrik · Jun 21, 2004, 06:39 AM

Done - No joy I'm afraid. Hopefully I'll get an RMA from CL soon.

**dj_stick** · Jun 21, 2004, 08:16 AM

that's too bad… i hope the card you get in return is fully functional