Topic: ASIO crackling noise on centre & LFE channels (Read 8976 times)

csy · « **on:** March 02, 2012, 06:01:58 pm »

I am having diffficulty getting J River 5.1 surround sound working with ASIO output to an exaSound e18 DAC. Front L/R and rear L/R work fine, however the Centre and LFE channels have a loud crackling sound overtop of the audio. I have proven it is not caused by the DAC or its driver software, as I can use Foobar and map the L/R to all 6 output channels and have clean sound. Additionally, within J River I can play a 6 channel FLAC file and the centre/LFE channels don't crackle.

The crackling noise occurs when I'm watching TV, recorded-TV, or DVD's containing AC3 5.1DD.

J River video setting is RO standard (also tried HQ). Right-clicking on the screen, it reports that it's using the LAV audio decoder and JRiver Audio Renderer.

In Options > Output mode settings > Channel offset, I can step the audio mapping however the crackling noise always stays on DAC channels 3 & 4 irrespective of the mappped surround channels.

I have tried J River version 17.0.82 and 17.0.99.

Help please!

Matt · « **Reply #1 on:** March 02, 2012, 07:37:00 pm »

That's a strange one.

What happens if you adjust the buffer size in Options > Audio > Output mode settings...?

Also, double-check Audio Path when watching a movie to make sure there isn't processing you don't expect.

csy · « **Reply #2 on:** March 02, 2012, 08:11:56 pm »

Thanks Matt for taking the time to read and respond - I really appreciate it!

I tried changing the buffer size to 0.2sec and also 1.0sec but no improvement.

I checked what is reported in the audio path while the movie was playing, and it is empty, OUT=IN

Any other ideas, or perhaps diagnostics I can do on the audio renderer?

Matt · « **Reply #3 on:** March 02, 2012, 08:35:00 pm »

To rule out bad decoding, what if you pick 2 channel output (with JRSS enabled) in DSP Studio > Output Format?

If that sounds good, I think it means decoding for the movie is working.

If you still hear a crackle, perhaps it's mastered into the movie?

csy · « **Reply #4 on:** March 02, 2012, 09:31:28 pm »

As a baseline, with 2-ch output configured (JRSS disabled), playing a 2-ch video, the front L/R sounds clean and the CTR/LFE (DAC ch 3&4) is silent
With 2-ch output configured (JRSS enabled), replaying the same video, the front L/R sounds clean (minus speech), and the CTR/LFE crackles loudly overtop of the audio.

As a baseline, with 2-ch output configured (JRSS disabled), playing an AC3 5.1DD video, the front L/R sounds clean (no speech) and the CTR/LFE (DAC ch 3&4) is silent
With 2-ch output configured (JRSS enabled), replaying the same video, the front L/R sounds clean (with speech), and the CTR/LFE is silent.

csy · « **Reply #5 on:** March 05, 2012, 12:07:36 pm »

Matt · « **Reply #6 on:** March 05, 2012, 12:16:53 pm »

Quote from: csy on March 02, 2012, 09:31:28 pm

With 2-ch output configured (JRSS enabled), replaying the same video, the front L/R sounds clean (minus speech), and the CTR/LFE crackles loudly overtop of the audio.

I think this indicates something is wrong on the source or decoding side, not the output side.

Do you agree?

csy · « **Reply #7 on:** March 05, 2012, 05:19:58 pm »

Hi Matt

That was with reference to a 2-ch source that sounds clean when outputed as 2-ch, which proves the source is clean.
I guess I confused the issue a bit by adding additional diagnostic information relating to testing using 2-ch source material.

I'll start again.

Using 5.1 source video.
Output set to source number of channels (or 5.1) (JRSS disabled), L/R & SL/SR sound clean, CTR/LFE crackle loudly overtop of audio
Output set to 2-ch and JRSS enabled, L/R sound clean with speech, CTR/LFE silent

To me, this proves it is not a source or decoder issue. Where to from here?

Matt · « **Reply #8 on:** March 05, 2012, 05:33:08 pm »

Quote from: csy on March 05, 2012, 05:19:58 pm

Using 5.1 source video.
Output set to source number of channels (or 5.1) (JRSS disabled), L/R & SL/SR sound clean, CTR/LFE crackle loudly overtop of audio
Output set to 2-ch and JRSS enabled, L/R sound clean with speech, CTR/LFE silent

To me, this proves it is not a source or decoder issue. Where to from here?

What does it sound like if you use testing tools like Level, Solo, etc. buttons on DSP Studio > Room Correction while playing?

I mean, does a simple tone sound distorted? Is there any chance the soundcard driver is doing something extra and unexpected?

Creative ASIO for example routes the default 5.1 channels into outer space channels like (ceiling center) and then remixes those weird channels back into the channels you actually hear but in a weird way. It's very confusing.

csy · « **Reply #9 on:** March 07, 2012, 12:46:01 am »

Ok, I have sequentially selected 'solo' for each channel and ensured the audio appeared out the correct (and only) speaker, and there appears to be no weirdness like you mentioned.

Next I performed the 4 test tools on the CTR and LFE channels, with the following results:
Tone test: audio + tone + crackle
Solo test: audio only (no crackle)
Mute test: silent
Level test: tone only (no crackle)

Matt · « **Reply #10 on:** March 07, 2012, 10:57:03 am »

Quote from: csy on March 07, 2012, 12:46:01 am

Ok, I have sequentially selected 'solo' for each channel and ensured the audio appeared out the correct (and only) speaker, and there appears to be no weirdness like you mentioned.

I think that means the routing is good.

Quote

Next I performed the 4 test tools on the CTR and LFE channels, with the following results:
Tone test: audio + tone + crackle
Solo test: audio only (no crackle)
Mute test: silent
Level test: tone only (no crackle)

I'm not totally clear, but this makes it sound like there is cross-talk between the center and LFE.

I mean, if each channel works on solo but crackles when you play both, doesn't that mean they're getting crossed somewhere at the hardware level? Possibly a bad solder joint or cable?

csy · « **Reply #11 on:** March 07, 2012, 12:16:22 pm »

I think your on the right track but the crosstalk does not appear to be coming from the DAC or its driver software. To prove this, I used Foobar2000 and mapped L/R across all 6 DAC channels in an alternating order as follows:
Ch 1: L, Ch 2: R
Ch 3: L, Ch 4: R (normally CTR/LFE)
Ch 5: L, Ch 6: R

The result was all 6 channels had clean audio, with all driven simultaneously. And note Ch 3&4 (nomally the CTR/LFE) had two different sources on them and had no crackle.

To me, this proves the DAC and its software drivers are not causing crosstalk, but I agree with your conclusions Matt that crosstalk appears to be the cause of the crackle when used with JRiver. I appreciate your contined investigation.

Matt · « **Reply #12 on:** March 07, 2012, 12:34:59 pm »

Quote from: csy on March 07, 2012, 12:16:22 pm

I think your on the right track but the crosstalk does not appear to be coming from the DAC or its driver software. To prove this, I used Foobar2000 and mapped L/R across all 6 DAC channels in an alternating order as follows:
Ch 1: L, Ch 2: R
Ch 3: L, Ch 4: R (normally CTR/LFE)
Ch 5: L, Ch 6: R

The result was all 6 channels had clean audio, with all driven simultaneously. And note Ch 3&4 (nomally the CTR/LFE) had two different sources on them and had no crackle.

What if you do the same test in Media Center, using Parametric Equalizer > Mix Channels?

csy · « **Reply #13 on:** March 08, 2012, 12:17:50 am »

It's cool that you can do this test in JRiver. I setup the following:
Copy L to C
Copy R to SW
Copy L to SL
Copy R to SR

Playing videos, the result was all 6 channels had clean audio, with all driven simultaneously. Where to from here?

Matt · « **Reply #14 on:** March 08, 2012, 09:33:15 am »

Quote from: csy on March 08, 2012, 12:17:50 am

It's cool that you can do this test in JRiver. I setup the following:
Copy L to C
Copy R to SW
Copy L to SL
Copy R to SR

Playing videos, the result was all 6 channels had clean audio, with all driven simultaneously. Where to from here?

I appreciate your detailed and logical testing.

I think we might be able to get to the bottom of it by selectively mixing channels.

I mean, you have it working right now on all channels by using only the L / R.

Can you toggle mixing and try different things to figure out if a particular input channel is to blame for the trouble?

For example, what if you play the C/LFE on 1/2 instead of 3/4? What if you play C/R or L/LFE on 3/4?

csy · « **Reply #15 on:** March 09, 2012, 01:01:53 am »

Ok, got some interesting results. There is crosstalk between CTR/LFE and SL/SR.

Crackle disappears under the following conditions:
source channel 'a' feed both CTR and SL
source channel 'b' feed both LFE and SR

It doesn't matter what the source channels are, so long as the above conditions are met. If you only apply one of these conditions like copy CTR to SL but leave LFE and SR as independant channels, then the crackle still occurs on both CTR and LFE speakers but the amount is halved (volume of the crackle remains unchanged but the amount of crackle is less). In other words, SR is crosstalking into CTR and LFE channels. And vice-verca happens with SL if you swap the test conditions.

Something else of interest, when no mixing is configured, the crackle on C/LFE stops when you go into Room Correction and mute SL and SR channels. If you mute only one of those channels, say SL, then the mating channel (SR) still crosstalks into both CTR and LFE but the amount of crackle is halved. And vice-versa with SL is you mute SR instead.

csy · « **Reply #16 on:** March 09, 2012, 03:09:34 am »

I've been doing some some additional testing, this time using an ASUS Essence ST soundcard with H6 expansion board. This soundcard supports 6 channel ASIO, so is good to do back-to-back comparisons with the e18 DAC.

The Essence ST soundcard has no problems with 5.1 videos outputed over ASIO. I am now of the opinion that the e18 DAC is the cause of the crosstalk. I had previously considered it ok from my Foobar2000 testing mentioned in an earlier post, but my last lot of testing has shown that my Foobar2000 testing was flawed.

I will now address this with the DAC maufacturer. I would like to say a big thank you to Matt for your support - I really appreciate it!

Matt · « **Reply #17 on:** March 09, 2012, 06:48:03 am »

Amazing detective work.

Please let us know what you learn from the e18 manufacturer. Feel free to give them my email (matt at jriver dot com) if there's something we can help with.

elsid · « **Reply #18 on:** March 09, 2012, 07:36:39 am »

One last troubleshooting piece could be trying a new usb cord (if i read the info for your e18 properly). Maybe a different usb socket on your pc - preferably one on a different header i.e. front usb instead of rear. Make sure your mobo drivers are up to date, etc.

faenjeggiropp · « **Reply #19 on:** March 25, 2013, 06:45:55 pm »

What happened to this issue? I have the exact same problem with my exaU2I receiver. In normal mode all channels are clean. If I use the parametric equalizer to copy one channel to another, it's starts crackling.

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Author Topic: ASIO crackling noise on centre & LFE channels (Read 8976 times)