How much mid bass is sent to height channels?

[K man]

How much mid bass energy is typically sent to height channels?

Most height speakers doesn't go very deep and may benefit from being crossed over at 120Hz or even higher. At the same time you don't want to cross over subwoofers too high, preferably below 100Hz, to avoid them becoming localisable.

This dilemma got me wondering how much mid bass (e.g. 80 - 150Hz) energy that is actually sent out to the height channels. If this is mostly filtered out already in the receiver, there is in practice no problem with crossing the heights around 80 - 100Hz since they won't be pushed hard in that area anyway. While if the receiver push bass energy to the heights in the same way as to the surrounds, the issue is more real.

I haven't been able to find a good source on this. Is there anyone here who holds the knowledge or could point me to a good source on the topic?

 

[K man]

Since I haven’t yet received any replies to this, @amirm could you maybe point me to someone who might know? (Alternatively point them to this thread.)

 

[Timcognito]

https://www.dolby.com/siteassets/technologies/dolby-atmos/atmos-installation-guidelines-121318_r3.1.pdf

 

[K man]

https://www.dolby.com/siteassets/technologies/dolby-atmos/atmos-installation-guidelines-121318_r3.1.pdf

Unfortunately that document doesn’t treat height speakers at all, only overhead speakers.

It doesn’t say a lot about the amount of bass sent to overhead speakers either, only that they should be tonality matched with the listener level speakers.

 

[Duke]

My recollection is that the ear's ability to judge the height of a sound source decreases rapidly below 1 kHz or so, so I don't think there would be much point in sending energy as low as 120 Hz to height speakers. But I have no direct knowledge of the low-end cutoff of something like an Atmos system.

 

[Shadrach]

How much mid bass energy is typically sent to height channels?

Am I right in thinking that you're asking how much a sub adds to the systems bass performance above the crossover frequency?

I'm relatively new to the world of subs and have only tried two makes in my system.
I tried the KRK S10 and the Genelec 8050C. I bought the Genelec.
Setting them up with some test tones was fun, especially when in the 20Hz to 50Hz range; how low will the subs go testing.
What I wasn't really prepared for was just how much of an improvement it made to frequencies normally just handled by the monitors.
This may be make dependant; both subs and monitors are Genelec in my system.

 

[DVDdoug]

All channels (except the LFE) are full-range capable, including the full bass range. The content of the channels is up to the producer.

But since most home setups don't have multiple full-range speakers, AVRs have "bass management" that allows you to select "small", "medium", or "large" speakers so you can optionally send all of the bass to the subwoofer, mixed with the LFE channel which ONLY goes to the sub.

 

[K man]

My recollection is that the ear's ability to judge the height of a sound source decreases rapidly below 1 kHz or so, so I don't think there would be much point in sending energy as low as 120 Hz to height speakers.

That’s a good rationale and argument.

But…

The content of the channels is up to the producer.

… is also a good argument, for the opposite.

The statement that the height speakers should be tonality matched with the listener level speakers could also be read as implying that they should be able to reproduce mid and upper bass in the same way.

So I’m still left here wondering if the height speakers inability to reproduce mid bass is a real issue or not.

 

[Duke]

That’s a good rationale and argument.

But…

… is also a good argument, for the opposite.

The statement that the height speakers should be tonality matched with the listener level speakers could also be read as implying that they should be able to reproduce mid and upper bass in the same way.

So I’m still left here wondering if the height speakers inability to reproduce mid bass is a real issue or not.

I appreciate the importance of timbre-matching, but you might consider this:

Your main speakers probably already have excess in-room energy over most if not all of the region below maybe 700 Hz or so, therefore arguably you don't need even more in-room energy in that region being added by the height speakers for the sake of "timbre matching".

That being said, I can see an argument for height speakers having the same fullrange tonal balance as the main speakers IF the height speakers are receiving unique fullrange signals which are not present in the main speakers. But I rather doubt that multi-channel recordings with dedicated height channels are mixed this way because of the impracticality of installing true full-range speakers in the ceiling. For example, I'm not aware of any ceiling speaker that can "keep up with" the Revel Salon 2 all the way down the spectrum. Obviously I'm making the assumption that dedicated height channel signals are mixed with practicality in mind. [EDIT: See @Mr. Widget 's post #11 below; my assumptions about height channels having significantly limited low frequency content are INCORRECT.]

 

[Andysu]

i think some low end in the overhead when monitoring just the overheads
no time to bond it

JBL professional cinema THX here

 

[Mr. Widget]

I appreciate the importance of timbre-matching, but you might consider this:

Your main speakers probably already have excess in-room energy over most if not all of the region below maybe 700 Hz or so, therefore arguably you don't need even more in-room energy in that region being added by the height speakers for the sake of "timbre matching".

That being said, I can see an argument for height speakers having the same fullrange tonal balance as the main speakers IF the height speakers are receiving unique fullrange signals which are not present in the main speakers. But I rather doubt that multi-channel recordings with dedicated height channels are mixed this way because of the impracticality of installing true full-range speakers in the ceiling. For example, I'm not aware of any ceiling speaker that can "keep up with" the Revel Salon 2 all the way down the spectrum. Obviously I'm making the assumption that dedicated height channel signals are mixed with practicality in mind.

The Dolby Atmos spec for commercial cinema calls out response to at least ±3dB at 90Hz if bass management is used. Most of the mixing suites that I have seen use speakers that roll off below around 60Hz.

 

[Duke]

The Dolby Atmos spec for commercial cinema calls out response to at least ±3dB at 90Hz if bass management is used. Most of the mixing suites that I have seen use speakers that roll off below around 60Hz.

Wow. I stand corrected!

 

[K man]

The Dolby Atmos spec for commercial cinema calls out response to at least ±3dB at 90Hz if bass management is used. Most of the mixing suites that I have seen use speakers that roll off below around 60Hz.

So most home height (and overhead) speakers’ limitations in the mid bass area is an actual and real limitation?

 

[Mr. Widget]

So most home height (and overhead) speakers’ limitations in the mid bass area is an actual and real limitation?

I haven't paid attention to the limitations of typical home theater surrounds, height, and Atmosphere overhead speakers, but as long as your processor handles bass management properly and your speakers are flat below 100Hz you should be fine.

I know of a high end mixing studio that uses Meyer Sound Ultra X-23s for all surround and Atmos speakers. They are rated at ±4dB down to 65Hz, so while they are limited in the upper bass, the Dolby Cinema Processor manages the bass and allows the mixer to create high quality Dolby Atmosphere mixes.

 

[Andysu]

low end on overheads can go down to as low as what is decently mixed to 5Hz

watched again that rubbish , no time to bond it , it had few low end below 30Hz 25Hz but its dreadful movie , dreadful colour and 4k , so no spectrum lab to share on that it wasn't really worthy enough

moonfall , dreadful colour , movie studios should stop this dire colour look ,
soundtrack wise music score sounded same as the regular channels , thou music score on the overheads is mixed at low level , there is few seconds where it raises up some dB then back down at same levels , while screen channels or other surround side back maybe too high and most home cinemas wouldn't notice the amount of , audio frequency masking effect , levels have to be adjusted for each playback of a movie

actual frequency went down low enough below 20Hz , need arrays of behringer DCX 2496 to crossover the speakers and have sub for each ,
height 1 , height 2 , height 3 , height 4 , height 5 and so on , diverting the lows to single sub won't work correctly otherwise would have to sound rehearsal checking which signal needs to be lowered otherwise would only hear a confusing blend of LCRSsBsOsLFE a mess !

scenes below from moonfall monitored on THX 3417 amp return of one of the overheads height 1 , Dolby SA10 being used for more pinpoint sound that i call " DOG channel " or DOG 1 here , Behringer EPQ304

i think this is the space shuttle with one of the SRB being detached had explosive bolts , jolt boom with air rushing , well that looks low to me , that what is going on below 10Hz

no crossover used on my JBL 8330A x9 , even the extra channels below surround JBL control 1 that are on the floor

gravity on the opening music that builds up in all channels than whoosh loud sounds like the air being sucked out of the room to the silent cosmic solar winds that is uniform in all channels and has constant movement , it has lows below 20Hz thou rolling off with amplitude level

i can only connect so many channels to THX 3417 , i need a special made of 32 channels , not going to happen

 

[K man]

Thanks a lot for all the effort, @Andysu. Appreciated.

So indeed it seems like bass energy is pushed into all channels, including height and overhead. Perhaps with the only difference that the overall energy level (in all frequencies) is lower than in the listener level speakers.

I haven't paid attention to the limitations of typical home theater surrounds, height, and Atmosphere overhead speakers, but as long as your processor handles bass management properly and your speakers are flat below 100Hz you should be fine.

Currently, KEF R8 Meta is one the very best (and more expensive) height speakers:

KEF R8 Meta Dolby Atmos Speaker Review

This is a review and detailed measurements of the KEF R8 Meta Dolby Atmos Surround Speaker. It was kindly drop shipped to me by a member and costs US $1,600 for a pair. The R8 meta is very compact speaker meant to be put on top of your tower surrounds (or bookshelves on stand) to fire up at the...

www.audiosciencereview.com

(Here is its prequel: https://www.erinsaudiocorner.com/loudspeakers/kef_r8a/ )

Still, its distortion goes up quite dramatically below 200/300Hz, with a bass falloff starting around 150Hz or so.

There is a distinct lack of measurements available on height speakers, but considering that almost all other models are (often much) cheaper and have an equal size (e.g. Monitor Audio Silver AMS) or smaller (e.g. SVS Prime Elevation, Dali Alteco C-1, Polk Audio R900, Elac Debut A4.2, etc.) woofer I wouldn't expect them to be any better in that regard.

This causes a gap between how low the height speakers are able to play (clean) bass and where you would normally put your crossover to offload them.

 

[Andysu]

overhead speakers been in use for decades , even when projectionist at CIC/UCI tower park , in all 10 screens
large screen 5 6 use x8 , smaller 1 to 4 , 7 to 10 used x7 overhead , since 1989 for tower park , other sites maybe since 1988 ,

odeon now home to the pigeons , cinerama 70 used overhead surround since 1969 , ice station zebra , and phased out 1970 35 install , five behind screen and overhead x6 , heard star wars day one feb 1978 with overhead star destroyer , day one , Dolby Stereo via CP50

see if you can spot x6 flush overheads , other speakers are JBL 8330 mkI that cinema installed 1999 for jar jar binks in SR-D , heard the matrix SR-D few weeks before episode 1 , actually the original overhead sounded better , last heard early 1998 ,, i think got broken ? not matters now , its home to the pigeons

so what you been reading mostly about atmos is mislead bs dolby labs , of course if public knew they be asking lots of questions
overheads at tower park was experimental and never publicised as cinema with overhead even if , so what if its Dolby Stereo matrix 4.2.4 ,
i wired special box so i can use the tower park effect on switch B or switch A will be Atmos , discrete overheads

i take the common surround signal and it can play on the sidewall back wall as well as overhead or i can switch off side/back and let play like UCI tower park ,
Dolby Stereo matrix or Dolby dts discrete , most home cinemas can't do what mine can do , and if you wanted the same it be not personal to you or anyone , as you never experienced it , but it works

 

[Reverend Slim]

How much mid bass energy is typically sent to height channels?

Most height speakers doesn't go very deep and may benefit from being crossed over at 120Hz or even higher. At the same time you don't want to cross over subwoofers too high, preferably below 100Hz, to avoid them becoming localisable.

This dilemma got me wondering how much mid bass (e.g. 80 - 150Hz) energy that is actually sent out to the height channels. If this is mostly filtered out already in the receiver, there is in practice no problem with crossing the heights around 80 - 100Hz since they won't be pushed hard in that area anyway. While if the receiver push bass energy to the heights in the same way as to the surrounds, the issue is more real.

I haven't been able to find a good source on this. Is there anyone here who holds the knowledge or could point me to a good source on the topic?

The content itself is full range, so with in-ceiling/on-ceiling speakers, it's like any other channel. If you're talking about upfirers, they are usually designed to cover down to about 120Hz. When you set up the upfirers in your AVR, my recollection is that the bass for those gets redirected to the adjacent ear-level speaker at about 150Hz (or subject to its crossover setting), with the rest being subject to the bass management assigned to that corresponding ear-level speaker. This keeps the directional part of the bass in that general region of the room and off the sub to prevent localization. In other words, if I have a left front speaker crossed at 80Hz and an upfirer on it set to 150Hz, bass from 80-150Hz for that height channel is reproduced by the left speaker and then everything from 80Hz down for both the left speaker and the upfirer is passed off to the sub.

 

[K man]

The content itself is full range, so with in-ceiling/on-ceiling speakers, it's like any other channel. If you're talking about upfirers, they are usually designed to cover down to about 120Hz.

What I've been talking about is neither in/on-ceiling speaker nor upfirers, but height speakers, that are placed on the wall but up close to the ceiling.

It's interesting what you write about the crossover of 150Hz for upfirers though, since it seems most speakers on the market in the regard is dual purpose upfirers and height speakers. That could explain some of it, since many of those may have been designed primarily as upfirers and only secondarily as height speakers.

It doesn't explain it all though, since most of the dedicated height speakers - such as SVS Prime Elevation, Dali Alteco C-1, etc. - are also using 4"/4.5" woofers. Limiting their ability to reproduce both low and mid bass.

 

[Reverend Slim]

What I've been talking about is neither in/on-ceiling speaker nor upfirers, but height speakers, that are placed on the wall but up close to the ceiling.

It's interesting what you write about the crossover of 150Hz for upfirers though, since it seems most speakers on the market in the regard is dual purpose upfirers and height speakers. That could explain some of it, since many of those may have been designed primarily as upfirers and only secondarily as height speakers.

It doesn't explain it all though, since most of the dedicated height speakers - such as SVS Prime Elevation, Dali Alteco C-1, etc. - are also using 4"/4.5" woofers. Limiting their ability to reproduce both low and mid bass.

If you're just talking about speakers that have an angled baffle for that purpose, then I doubt there is any intentional limitation to their response. They're just trying to design the smallest speaker for that purpose. In my experience, you're likely better off just getting a bookshelf with mounting threads so you can properly aim the speakers rather than a speaker with a built-in baffle angle that may not be optimal for your placement.

The Prime Elevation are a perfect example. SVS uses a 20 degree baffle angle, so if you place them at the customary 30 degrees for front/rear height, they aren't really quite on-axis. Worse, their mounting bracket puts them so close to the wall that while they may perform to SVS' quoted specs when free-standing, they can't get anywhere close when mounted on the wall with so little port clearance. I have 4 of them mounted on my ceiling and SVS' claimed -3dB point of 55Hz is wishful thinking, with them actually measuring around 110Hz in practice.