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Good speakers with tiny subwoofers, and why that's backwards.

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Chromatischism

Chromatischism

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At the levels I've calibrated the fronts and surrounds, the channels do not compress at 0dBFS. The single sealed 12" sub that I use does, however, start to compress right around -3.4 dB -- but this is primarily below 20Hz (infrasonic).
Are you referring to digital clipping? I am not. I am referring to the physical sub not getting any louder when volume is increased due to lack of excursion or amplifier power. Without headroom, what would have been dynamic peaks are the same loudness as other content.
 
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Chromatischism

Chromatischism

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let me demonstrate, the latest movie I watched was the The Witcher Nightmare of the Wolf, a very action packed movie. Looking at the audio we see that the center channel has an average RMS of -28 dB while the LFE channel has an average RMS of -40 dB (the LFE is probably boosted by 10 dB later on).
I looked for a heatmap of this movie and couldn't find it, but it's possible it is a poor example for LFE.

Here is the example I referred to earlier.

Green = Peak LFE level
Red = Average LFE level

sf9Pj67 - Imgur.png


My point is you need headroom for the peaks.
 
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wwenze

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Apparently this is also a problem with mixer software. Proof: Audacity, generate sine tone at 0.1 amplitude (-20dB), check with amplify tool to make sure it is -20dB. Generate the identical sine in another track. Downmix or export and reopen again. Check new file with amplify tool.

Result: -14dB

So the lesson here is to avoid downmixing altogether?
 
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Chromatischism

Chromatischism

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If Reference is 85dB, and Reference is at 0, then how can -20 be at 85 dB?
Reference is 105 dB.

Speaker channels:

Speaker%20reference%20level.png


LFE channel:

Subwoofer%20reference%20level.png


http://www.acousticfrontiers.com/2013314thx-reference-level/

So the discussion here is about taking those standard THX levels and giving yourself 10 dB more headroom to account for bass boosts most users add, and redirected bass from all speaker channels because you never know when that will be an issue.

It's just a general recommendation and you can of course push into that headroom if you want by using smaller subs. You may just encounter dynamic scenes that max out the subs and are then less dynamic.

Music doesn't have a reference level, but you still want your subs to be more powerful than your speakers because we often run them a little elevated in proportion, anywhere from 3 to 10 dB. Sometimes more.
 
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richard12511

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Then why advocate for bigger subs instead of full range speakers?

I think price is one difference. Great subs are much cheaper than speakers with similar bass output. For a good value $3-$4k subwoofer, even a $200,000 Focal Utopia would have trouble keeping up. Speakers that can do 115dB full range tend to be very, very expensive, at least from what I've seen. Not saying 11 Salon2s wouldn't be epic, but 3 Salon2s, bookshelfs for surrounds, and 4-8 Rythmik F18 would be much cheaper and still give better extension and headroom.
 

ernestcarl

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Are you referring to digital clipping? I am not. I am referring to the physical sub not getting any louder when volume is increased due to lack of excursion or amplifier power. Without headroom, what would have been dynamic peaks are the same loudness as other content.

It is not possible to increase volume past my maximum (relative) SPL calibration which is why dynamic peaks are unlikely to be compressed. If I disable volume leveling, it is possible that the sub would start to compress if I see peaks in the infrasonic range going beyond -3.4 dB (still not digitally clipping). As volume rapidly increases or true peak goes beyond 0dBFS, JRiver automatically "soft clips" and/or lowers the overall system volume whether or not Volume Leveling is set in place. There is going to be some extra headroom (for certain) because I have not calibrated at this "85dB standard" -- having taken into account the actual SPL limitation and distortion characteristics of the sub and satellites beforehand. For example, there is no point playing so loud to the point where my surrounds (LSR305) start to distort too much. As I see it, not many people realistically listen at such high volume "reference" levels anyway even when they might own decent-sized speakers and sub(s) already.
 
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Chromatischism

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It is not possible to increase volume past my maximum (relative) SPL calibration which is why dynamic peaks are unlikely to be compressed. If I disable volume leveling, it is possible that the sub would start to compress if I see peaks in the infrasonic range going beyond -3.4 dB (still not digitally clipping). As volume rapidly increases or true peak goes beyond 0dBFS, JRiver automatically "soft clips" and/or lowers the overall system volume whether or not Volume Leveling is set in place. There is going to be some extra headroom (for certain) because I have not calibrated at this "85dB standard" -- having taken into account the actual SPL limitation and distortion characteristics of the sub and satellites beforehand. For example, there is no point playing so loud to the point where my surrounds (LSR305) start to distort too much. As I see it, not many people realistically listen at such high volume "reference" levels anyway even when they might own decent-sized speakers and sub(s) already.
I certainly don't listen at reference and I don't recommend it if you value your hearing. That's why I watch movies at -20 (85 dB). Reference is 105 dB. Don't try this at home, kids!

For music I trend a little lower, probably 75-80 dB.
 

ernestcarl

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Reference is 105 dB.

105? I thought in the graphic you posted, it says reference level per speaker channel is 85dB using a -20dB calibration pink noise. 105dB is the peak maximum. For the sub, 115dB at least, minus the additional possible coherent summing effect as a consequence from bass management. So I can totally understand your concern about smaller subs.
 
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Chromatischism

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The -20 (or sometimes -30 in an AVR) test tones are used because reference level sound would be very offensive to most consumers in their homes :)

Knowing the offset, accurate calibration is still obtained.
 

MattHooper

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Reference levels for films (mixing) is 85db. That’s what the rooms are pinked at. Of course peak levels will be higher but I hope to god someone isn’t regularly listening at a 105db average thinking it’s reference level.
 

KMO

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If Reference is 85dB, and Reference is at 0, then how can -20 be at 85 dB?

Reference level has general level at 85dB (and the test tones are played at that level), with 20dB headroom for peaks to 105dB.

He's turned it down 20dB so content is at 65dB average, with peaks to 85dB.

So one is referring to general level, the other to peaks.

And in home environments, reference level feels louder than in a cinema, so typically you'll use master volume at least 10dB down from reference, so 75dB typical content. And home receiver test tones are usually down 10 at 75dB.
 

abdo123

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I think price is one difference. Great subs are much cheaper than speakers with similar bass output. For a good value $3-$4k subwoofer, even a $200,000 Focal Utopia would have trouble keeping up. Speakers that can do 115dB full range tend to be very, very expensive, at least from what I've seen. Not saying 11 Salon2s wouldn't be epic, but 3 Salon2s, bookshelfs for surrounds, and 4-8 Rythmik F18 would be much cheaper and still give better extension and headroom.

They don’t need to do 115 dB, just 105 dB.

And usually most content would be fine with a speaker with an F10 of ~20Hz.

I mean it’s not cheap for sure, but floor standers come with even more headroom so it’s not like people are paying for just the LF extension.
 

KMO

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They don’t need to do 115 dB, just 105 dB.

Speakers would need to do 115dB if you didn't have a sub and tried redirecting LFE to them (which some receivers can do). That's what Richard was arguing against.

(But the normal expectation is that LFE is dropped in the absence of a sub - it's "extra" content for people with subs who have the headroom).
 

abdo123

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Speakers would need to do 115dB if you didn't have a sub and tried redirecting LFE to them (which some receivers can do). That's what Richard was arguing against.

I never said that you can’t have a subwoofer, I’m just arguing for the people who go the extra mile so that everything else is full range the way it should be.

Most Atmos mixing rooms have full range setups, it is the ideal. With a subwoofer just so they would hear what the LFE in the end product would sound like.
 
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Chromatischism

Chromatischism

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Reference levels for films (mixing) is 85db. That’s what the rooms are pinked at. Of course peak levels will be higher but I hope to god someone isn’t regularly listening at a 105db average thinking it’s reference level.
I guess this wasn't explained but I didn't want to make a thread on "what is THX reference level" which is easily searched online. It is indeed referring to the peak SPL level.
 

KMO

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I never said that you can’t have a subwoofer, I’m just arguing for the people who go the extra mile so that everything else is full range the way it should be.

Oh, right, got you. Followed back to understand your original question, which I didn't quite understand at the time.

Yes, if you had full-range speakers and shut off the bass management, the extra demand on the sub goes away. Spreads the SPL load.

But bass management has a number of advantages - free placement of subs, spreading the amplifier power load better, space, price...

10dB of extra sub headroom is probably easier to stretch to than going full-range all channels.
 
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