Bass, tactile feedback, that feeling!

Home Theater Lobby
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One interesting question for the folks in this hobby …

When playing back this clip below on midbass, I noticed a couple of things in different rooms , try if you haven’t

The special effects are centred around 65hz to 27hz, very fast attacking midbass punches…

What I’ve come to realise calibrating different rooms is this…

In some of the rooms, the tactile feedback from punches are not felt at chest level, but more on the gut area. In other rooms, it is felt at buttocks area. And in some other rooms, it is felt at chest levels…

So I dived in deeper, to segregate what I’m experiencing…

1)is the amplitude response good ?All the rooms had a good amplitude response from 65hz to 27hz.

  1. Is it due to stack ? No. Another room without stacked subs are able to reproduce the midbass bass slam at the chest area … with only 2 subs left right

  2. is it due to decay? No. An untreated room with decay times of 500ms can equally produce this type of slam to the chest

  3. is it due to timing on the subs? No also, delay another subs timing handling 45-27hz didn’t make the tactile slam move up to chest level

  4. is it due to quality of the subs ? Type of drivers? Type of design? No also. At the moment, the same sub in room A had the slam to the chest whilst the same sub at room B don’t have that slam to the chest !

  5. is it due to subwoofer isolation? No again. One isolated with Gaia footers one doesn’t, the one with Gaia couldn’t produce the slam to the chest. Whilst another isolated with granite was able to. So again it’s not the isolation from the floor.

  6. tactile transducers/ shakers. Hoverboss platforms. These confirm don’t help and might worsen the situation when the delays are not dialed in correctly.

  7. could it be the sofa ? Is the sofa absorbing most of the tactile feedback and shake that it now takes away the inertia for slam to the chest ? I think so… but I’m not sure… this is very interesting

Finally, is it really supposed to slam the chest ? Because the opponent is on the ground. The punches are happening on the ground… so naturally it should be felt at the gut area if the foley mixer mixed it that way …

But strangely, 10/10 folks like the chest slam over the slam at gut area or back seat . It is quite similar when it comes to bullet scenes. As this gives the system a good layer of separation, from legs, gut, chest to head tactile feedback. A multi layered tactile experience is quite different. The bullets piercing through chest levels feels more realistic compared to bullets piercing the buttocks area

What is your experience with this clip ? Do you enjoy tactile feedback at chest level or gut area ? Especially for midbass ? The general population in this hobby seems to prefer the chest area, but they are asking me a question I have no answer to… I have absolutely no idea how to measure this and how to recreate this effect… but it is something that is desired by many…

Do share your experiences, looking forward to it …

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Oh yes, on my set up, for this particular scene, the slam of tactile is happening at chest level ! It doesn’t track the on screen action ! But I’m not sure where it’s supposed to slam. The on screen action shows slam happening at gut area…

But when I come to bullet scene, they sound accurate tracking on screen action, the bullets hitting the chest…

So quite interesting track, not only it’s able to tell u how the tactile slam is happening, it also tells u how fast that slam is happening…

Quite a good clip for midbass attack, especially someone looking to purchase a subwoofer, it tells u the type of signature coming from that subwoofer, weighty, fast and light , piercing , bouncy… etc etc

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No file to the link you supply.

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alamak let me relink

here use this

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flashpoint LFE signal
flashpoint LFE signal1894×975 206 KB

so here i have extracted the signal on this clip, there is more than sufficient headroom in the digital domain. It has 20dbfs in headroom before reaching the full 115db on the LFE signal going into the processor or AVR. So again distortion in digital domain is out of the question. Even if you boost the Processor by +10db, there is still plenty of headroom.

So no issues with playback even if you have boosted the subs by +10db… so dont need to worry about damaging the subs.

And to confirm, 100db between 27 - 65 hz is more than sufficient to produce this tactile slam on the chest… dont need to blast to insane levels to feel this…

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two common things i found is that

  1. all the rooms using a fabric type of sofa wasn’t able to reproduce the slam on the chest, whilst all rooms using a leather type sofa was able to produce the slam to the chest…

  2. All the rooms with subwoofer at corner placement was able to produce this slam to chest whilst those without couldnt. Could it be due to placement & location of the subs ?

these are the only 2 common things i have noticed that is consistent… for now…but will need more time to find out… Because it cannot be seen with any of the measurement tools or test files. Maybe someone has some type of vibrometer to establish this… not sure how it is done…

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Thx for starting this good topic! I love good bass tactile and imo, besides the bass time alignment, n having a HC, it’s the critical factor to getting v awesome bass in the listening position.

More often than not, in usa/ang mo forums, i find this is not discussed. Their discussions seem to focus more on digging low and the output.

Happy that our HT community here have good insights n interest in this area. :muscle:

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I find the sofa a v big factor in transmitting bass tactile,and affecting how the tactile turns out

Esp the type of cushioning and build structure of the sofa.

My observations so far are: sofas that hv soft cushioning/ no structural frame support, tend to vibrate v easily with bass.

Eg. if a sub’s driver is placed NF facing the sofa, the sofa w overly vibrate even in mid bass freq. This causes strong tactile vibrations across the sofa surface in mid bass freq, resulting in unnatural bass tactile. Many a times, it is felt by the butt, back and gut. It is made worse by the fact that chest thump needs the bass spl to reach a certain loudness in the room to be able to be felt clearly in the mlp. So the more u tune up the bass to be able to feel chest thump, the more the soft cushion vibrates! By the time u raise the spl of the subs to be able to feel the chest thump, the vibrations on the sofa becomes so strong liao till u cannot even distinguish the chest slam.

But sofas with firmer cushion can control this well and allow chest thump to be felt mor easily.

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Your finding of the diff between Fabric and leather is rather interesting…

I did find the chest thump improve after i changed from fabric to leather sofa a year ago. I cant explain why too but it’s interesting.

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Very Logical indeed … I have the same experience but wasn’t sure

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I concur, the discussion on overseas forum focuses a lot on output. Less so on bass articulation. A lot of times we keep seeing data bass measurements, and how 21” subs or 24” subs are able to dig down low effortlessly with decent SPLs . Very less is talked about mid-bass and how the tactile slam is different with the same source content…

But how that midbass affects the deepbass (in terms of tactility) cannot be ignored… the experience is then different because whether midbass kicks in or low bass kicks in, they are all concentrated at the butt area… so there is a lack of tactile feedback at differing heights of the body…The upper regions in of the midbass from 80-120hz, that trickles down to 30hz is equally important, then finally down to the infrasonics

So it appears that you have discovered that the type of sofa we sit on has a huge impact with tactile feedback and how one experiences bass… with the same content…

Have u changed sofa recently to experience this effect ?

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Sofa vibration aside, our body cavities have different resonant frequencies, gut vs chest.

So depending on the movie, where the frequency band of the impulse resides mainly, will resonate either the gut or the chest.

The resonant frequency of the body cavities vary across people as well. Large vs small, stout vs skinny…

i think think this chart, many likely seen before. Dunno where’s the source…

image
image547×720 60 KB

Found a few other references

image
image850×982 166 KB

https://www.researchgate.net/figure/Resonance-frequencies-for-different-body-segments-represented-by-a-simplified_fig59_317984098

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I’ve seen some Youtube videos use an iPad app with he iPad on the seat position to measure the level of vibration

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So I listened to the Bryan’s clip. My sub is nearfield and a few inches behind me, so unlikely to get any chest slam in isolation, but the onscreen chest punches do resonate throughout the whole body, not just the butt, chest and back, but pretty strongly on the arms and legs too. I turned off the Buttkicker to see what effect that had, and the impact on the arms and legs lessened considerably, but the butt, chest and back were still strong.

This may correlate with Gavin’s diagram above that the chest responds to 60Hz, while the arms, and especially legs respond to much lower frequencies. So, some of the impact may depend on how much infrasonic output you have, and certainly bass shakers produce a lot of that. Maybe upping the house curve on the infrasonic, may bring out a more even distribution of vibration throughout the body

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I’ve also just realised this, came back home , tested it again, I noticed the slam has direction, the punches are slamming the chest in the right left right direction… not only the chest gets pounded, but different sides of the chest are getting slammed , quite interesting…

I also turned off the line array subs that handles mostly the midbass, the deep bass subs are also producing the slam on the chest …

Then I used the recliner, recline the chair with legs up and head rested against headrest and it’s still there on the chest

So I have really no idea what is causing this tactile impact at the chest level

It is also not SPLs , with reduced SPLs , the slam is still present at the chest, just less intense …

House curve also nothing to do with it…

Gavin made a good point above on how our body response to certain frequencies. However this same body of mine, is having different feeling at different homes.

So I got this question from a client, why is it that some places have that chest slam and some don’t ? Hmm very interesting indeed… I have no answer to this tactile feeling… why ? I’m not sure…

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if I would venture a guess, it also depends on where is your MLP, particularly how near or far a person is relative to the placement of the subs.

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This is a mysterious topic. Haha…

Rem the kk12012 thump in the head area effect u managed to achieve in your den for the overhead kick for the legend demo scene? So far, i havent been able to replicate that in my den for strange reasons with dual kk12012. Even after upping the bass levels or HC.

Room? Sofa? MLP vs subs /wall? Ha…

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Adding 1 more strange observation/ phenomenon to this mysterious tactile science. Till today, i still cannot find the reason or understand why… Lol. Mind boggling.

In my listening area/room, (i dont think many will believe it), i cant feel much chest thump tactile at MLP even after dialing in a 12db HC slope on my dual subs (betw 100hz to 25hz slope). And i deploy a sub NF, the JL e112, which is strong in mid bass, to assist in the chest thump tactile with its driver facing mlp. So its strange…

In many dens, once a 8-10db HC slope is dialed in, and a nf sub deployed with driver facing the mlp, the chest thump can be quite prominent liao.

But in my den, for sufficient chest thump tactile to be felt in my mlp, i need to dial in at least a +15db slope between 100hz and 25hz.

Many have asked why i need to dial in such an aggressive HC slope & surprised at this peculiarity. Myself included. Lol

Sofa? Room? Mlp? Really cant understand.

This tactile thing in the room, is really an interesting (and mysterious) topic.

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Another element is the “movement of air molecules” within the listening space. An enclosed area vs an open living room. I believe it will also make a difference.

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But was the chest thump the intent of the director? Haha

Perhaps one should view the scene in a well calibrated Dolby Cinema to check…