How loud is loud, how to measure it? Is THX calibration bad for your health?

[solderdude]

Yes there is but that should be fixed once the reference level is calibrated. That is what level calibration means. In cinemas the volume control is behind a lock.

Cinemas yes... sound has to impress.
At home you have your volume control so see no reason for HT to be dangerous in that way.
Its mostly about exposure time and the tremendous SPL peaks are usually lowest bass and short lived for movies.
How often does the average person visit a movie theatre ?

 

[abdo123]

I'm honestly very disappointed in this thread, incredibly misinformative.

no A-weighting, using the reference level of a subwoofer instead of speakers. it's like there was zero actual research or care into the information provided.

 

[sarumbear]

Cinemas yes... sound has to impress.
At home you have your volume control so see no reason for HT to be dangerous in that way.
Its mostly about exposure time and the tremendous SPL peaks are usually lowest bass and short lived for movies.
How often does the average person visit a movie theatre ?

THX is a domestic standard. It doesn't meant for cinemas. Dolby standards are used for those. That is why you have a THX logo on your AVR?

I have linked what THX says about their refence level for home use. Here it is again. They have made it crystal clear what they want us to experience.

THX Certified Audio products are designed to let you experience movies the way they were meant to be heard. On every THX Certified AV Receiver the “0” on the volume dial represents THX Reference Level, the exact volume level used by the moviemakers and sound artists in the studio.

THX - WHAT IS THE REFERENCE LEVEL?

THX - WHAT IS THE REFERENCE LEVEL? - HOME

www.thx.com

 

[sarumbear]

This is for the LFE channel, not for speakers. for speakers it's 10dB lower!!!

Show me where this said in the standard, please.

 

[abdo123]

When i took these screenshots my system was calibrated to 0 dBFS @ 75dBSPL.

These were the readings with Z-weighting (basically no weighting) and A-weighting (the weighting used for safe noise levels).

 

[abdo123]

Show me where this said in the standard, please.

Have a closer look at the image you copied, it says LFE.

 

[solderdude]

But you still have the volume control if you think it is too loud for HT is my point. I don't care if someone else tells me how loud I should listen.
Now... I don't have any THX at home nor an AVR so it does not apply to me but I would assume that everyone using an AVR in HT can adjust the volume.

 

[sarumbear]

I'm honestly very disappointed in this thread, incredibly misinformative.

no A-weighting, using the reference level of a subwoofer instead of speakers. it's like there was zero actual research or care into the information provided.

A weighting is for noise not for music,
I am using the level in the listening position whatever the speaker is emitting at that track.
You may want to check the link on my post and follow the links on it. I copied it below for your benefit.

So How Accurate Are These Smartphone Sound Measurement Apps? | Blogs | CDC

CDC - Blogs - NIOSH Science Blog – So How Accurate Are These Smartphone Sound Measurement Apps? -

blogs.cdc.gov

 

[abdo123]

A weighting is for noise not for music,

Every safety recommendation when it comes to SPL level out there is A-weighted. you can't use them in any other context.

 

[sarumbear]

Have a closer look at the image you copied, it says LFE.

That is not reflective of the standard. I have also linked to the THX standard. Do please read it. I will however, edit the chart in order not to confuse other like you were.

 

[abdo123]

That is not reflective of the standard. I have also linked to the THX standard. Do please read it. I will however, edit the chart in order not to confuse other like you were.

Please correct the information in the thread or at least redact it, this is a very rookie mistake.

 

[sarumbear]

Please correct the information in the thread or at least redact it, this is a very rookie mistake.

View attachment 173256

What is the mistake here? It says 85dBSPL at -20dBFS, exactly as I wrote.

 

[abdo123]

What is the mistake here? It says 85dBSPL at -20dBFS, exactly as I wrote.

Are you kidding me right now?

Will it affect my health?

THX standard says that at reference level (-20dBFS, the broadcast/professional reference level) a Pink Noise should generate 95dBSPL at the audience position. As you can see from the simple chart below this means the theatre's sound system is expected to produce 115dBSPL without audible distortion.

View attachment 173257

 

[escape2]

I will however, edit the chart in order not to confuse other like you were.

There are two charts - one is for speakers and one for the LFE channel. See here:

THX reference level explained

What is 'THX Reference Level'? Reference level is a calibrated volume setting used for both movie production (in dubbing stages and post production houses) and reproduction (in screening rooms and theaters). The human hearing system is non-linear, especially in the bass, so having a consistent...

www.acousticfrontiers.com

 

[sarumbear]

Are you kidding me right now?

Obviously I am not kidding anyone, but do please entertain me and explain what is it that you found kidding?

Thank you.

 

[sarumbear]

There are two charts - one is for speakers and one for the LFE channel. See here:

THX reference level explained

What is 'THX Reference Level'? Reference level is a calibrated volume setting used for both movie production (in dubbing stages and post production houses) and reproduction (in screening rooms and theaters). The human hearing system is non-linear, especially in the bass, so having a consistent...

www.acousticfrontiers.com

I have posted the wrong chart by mistake. I will correct it. I appreciated if I had been pointed to my mistake instead of arguing though.

 

[sarumbear]

you wrote 95 dBSPL, you took measurements with your phone at 95dBSPL.

This is at best trolling at this point.

Yes I did and I said it is an average value. I simply chose a value 10dB higher than the reference. Isn't that what you expect to be an average level if the reference is at 85dB and peaks at 115dB?

I resent being accused of trolling. I hope the moderator will take action.

 

[storing]

You are talking about Health & Safety laws. I am talking about expected medical consequences. I am not a medical expert, hence cannot explain further.

Conceptually I'm also talking about medical consequences, which is why I'm wondering what references/standards you or the app use (or laws if you want, assuming they are based on research but knowing they might not take it strict enough in the medical sense): after all your claim is the app tells you something is bad for your health.

 

[abdo123]

Yes I did and I said it is an average value. I simply chose a value 10dB higher than the reference. Isn't that what you expect to be an average if the reference is at 85dB and peaks at 115dB?

No, Just like the standard that you link clearly states, 85dBSPL with 20 dB of headroom.

infact the RMS of the center channel is often between -30 dBFS and -25dBFS. Many mixers actually mix significantly below the THX reference. In Europe you have to follow the EBU R 128, which is slightly quieter than the THX reference.

 

[sarumbear]

Conceptually I'm also talking about medical consequences, which is why I'm wondering what references/standards you or the app use (or laws if you want, assuming they are based on research but knowing they might not take it strict enough in the medical sense): after all your claim is the app tells you something is bad for your health.

The app shows us the levels. It is the researchers tell us those levels are bad for your health. The app is only pointing you what those researches said in a simple way.

The research is on the Internet. Feel free to study. I personally do not want to. I trust CDC, as that is exactly why they exist.