Jonty Posted July 10, 2018 Share Posted July 10, 2018 Sorry about the title. I couldn't come up with a better way to describe what's happening! There's probably a technical term you guys use for this I've noticed a few times now when watching a movie via Chromecast Ultra through our AV system, that if there's a big/loud scene with a lot of deep bass, the speakers just can't seem to cope and we get these low knocking/farting sounds instead of the expected sound. If I turn down the volume enough (so we can't really hear/enjoy the movie) it seems to behave, but am hoping there's another way to fix it. Our setup is as follows: Hisense 55N7 ULED TV. Chromecast plugged into HDMI1 port of TV. Audio from TV to AVR via Toslink cable. Integra DTR 50.4 AVR with a pair of Dynaudio Emit M20 bookshelf speakers configured for 2.0 surround only. Connected with Duelund 16 awg speaker wire. AVR calibrated for 2.0 speakers running 'Theater Dimensional' mode. The TV has Netflix built in and we often watch movies with Dolby digital (you can see the AVR light up with the digital audio type when watching some Netflix content) and we have none of these audio issues that we get through the Chromecast device. Audio is 100% fine through Netflix via the TV. Likewise we have no problems watching Blu-rays/DVD's with digital surround through the AVR system, which is connected via a different HDMI port directly to the AVR. As far as I can tell, there's no real difference in terms of connectivity (as far as the AVR is concerned) between the Netflix audio coming from the TV and Chromecast. It's all coming via the Toslink cable out of the TV? The only available option I have that might relate to the Chromecast, is the TV has a 'HDMI 2.0 Format' setting, which can either be 'Standard' or 'Enhanced'. I've tried both settings for the Chromecast HDMI port on the TV, but it doesn't seem to help the audio issue. Any thoughts/tips much appreciated. Link to comment Share on other sites More sharing options...
Quark Posted July 10, 2018 Share Posted July 10, 2018 No sub? The AVR may be sending LFE signal to your speakers and shorting rings in the drivers are being reached as they're overdriven. Link to comment Share on other sites More sharing options...
Jonty Posted July 10, 2018 Author Share Posted July 10, 2018 Nope, no sub yet. Might be time to add one soon. Just surprising this only shows up in Chromcast as (I assume) there's plenty of other LFE content being sent to the speakers when watching via Netflix or DVD/Bluray and this doesn't happen on those sources. Link to comment Share on other sites More sharing options...
Quark Posted July 10, 2018 Share Posted July 10, 2018 Alternative is that the signal output from the Chromecast is too high and overloading the input on your AVR. 1 Link to comment Share on other sites More sharing options...
bris007 Posted July 10, 2018 Share Posted July 10, 2018 Does you receiver have digital sound level adjustment? If so turn down a couple of dB. 2 Link to comment Share on other sites More sharing options...
bris007 Posted July 10, 2018 Share Posted July 10, 2018 Does you receiver have digital sound level adjustment? If so turn down a couple of dB.On the Chromecast input. 1 Link to comment Share on other sites More sharing options...
Kaynin Posted July 10, 2018 Share Posted July 10, 2018 ^ Yes, this is possible. Remember that settings are often stored specifically for inputs. When I want the same adjustments across my TV/PC/blu ray, then I have to go select every input, then bring up the menu before making the same adjustment. 1 Link to comment Share on other sites More sharing options...
Jonty Posted July 10, 2018 Author Share Posted July 10, 2018 OK thanks guys. Will check it out tonight. In terms of the input to the AVR, the TV (inc Chromecast/Netflix) all goes through the one input on the receiver. So the input setting on the AVR that works fine for the TV when watching Netflix, is the same one used by the Chromecast device. Maybe the Chromecast has some adjustment for signal output. Link to comment Share on other sites More sharing options...
Guest thathifiguy Posted July 10, 2018 Share Posted July 10, 2018 2 hours ago, Quark said: Alternative is that the signal output from the Chromecast is too high and overloading the input on your AVR. I recall Chromecast Supporting Dolby Digital Plus, a format that has less compression than regular Dolby Digital. Could it be that this is resulting in a signal with greater dynamic range being sent to the receiver thus causing the "farting" of the drivers? Link to comment Share on other sites More sharing options...
Quark Posted July 10, 2018 Share Posted July 10, 2018 3 minutes ago, thathifiguy said: I recall Chromecast Supporting Dolby Digital Plus, a format that has less compression than regular Dolby Digital. Could it be that this is resulting in a signal with greater dynamic range being sent to the receiver thus causing the "farting" of the drivers? That could be a cause. Thinking a bit more, it could also be that the Chromecast is not able to decode some formats correctly e.g. multichannel. Link to comment Share on other sites More sharing options...
ZEN MISTER Posted July 10, 2018 Share Posted July 10, 2018 I think the correct technical term is ' transducer flatulence'. Helpfully, Billy. 1 Link to comment Share on other sites More sharing options...
Jonty Posted July 12, 2018 Author Share Posted July 12, 2018 (edited) On 10/07/2018 at 6:52 PM, Zen Mister said: I think the correct technical term is ' transducer flatulence'. Helpfully, Billy. Hahaha, I like it! Incidentally, I haven't been able to find any settings on the Chromecast, TV or AVR to adjust levels/format of what is being sent to the speakers that might resolve this. The TV has a 'Digital Audio Out' setting, which can be changed from RAW (what it's set to now), to PCM. Maybe I need to try PCM, but my understanding is that's only if your amp doesn't support Dolby Digital? Edit: I just found an LFE level setting in the AVR guide where you can set the LFE level for each input source, so maybe I need to back this off for the TV input... The other catch is I don't really have a reliable way to test this, without buying/renting a whole movie on Google Play, which only lasts for 48hrs. I've tried a few of the free previews, but they seem to play fine without any sound issues I get in the full movie. I have a feeling the previews don't have the same sound format as the rented/purchased HD movie though. I wonder if there's some content on Youtube which might show up the issue if I play it via Chromecast? Edited July 12, 2018 by Jonty Link to comment Share on other sites More sharing options...
Jonty Posted September 14, 2018 Author Share Posted September 14, 2018 Just an update on this, backing off the LFE Level on the AVR for the TV input has pretty much cured this problem. Watched a couple of movies on Chromecast recently and no more speaker farts. The only downside is that it's also dropped the volume of the other sources that come to the AVR via the TV, such as Netflix. I have to crank the volume a fair bit to hear the dialogue properly in most shows now. I think it's time to invest in a decent sub. Link to comment Share on other sites More sharing options...
Quark Posted September 14, 2018 Share Posted September 14, 2018 Good to hear you've got it sorted. A decent sub would a great move. Link to comment Share on other sites More sharing options...
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