Bass ‘chest thump’ at live gigs ?

[RayDunzl]

Having watched many CDs play, the preponderance of them (at least the ones to which I listen), are rolled off on the low end.

New ones, not as much.

Jethro Tull - Benefit - just because that's what was playing, one channel from the CD player analog outs:

Daft Punk Random - Access Memories:

Hey, we be thumpin' now...

 

[AudioSceptic]

When I lived in The Woodlands, there was a local "amphitheater".

One evening I heard thump-thump in the house.

Went outside, and it was recognizably Yes (1994 version).

Got on my bicycle, rode over there, and managed to sneak in.

2.7 miles straight line distance, through trees and houses and...

View attachment 36571


Shoutometer says:

View attachment 36577

So, say, 120dB at the cabs, -72dB = 48dB SPL at the house...

Not a bad guess.

---

In-room, 48dB SPL or so, measuring 20Hz and above:

Red is the level at which I was listening, black is the attenuated level.

Just recognizable (maybe since I know what's playing)

View attachment 36581

Hard to be accurate about this because air temp/pressure and wind (speed and direction) makes a big difference, surely?

 

[RayDunzl]

Hard to be accurate about this because air temp/pressure and wind (speed and direction) makes a big difference, surely?

Oh yeah, plenty of acoustic variables available to argue if you want.

 

[PaulD]

‘Chest thump’ at live gigs, can it be recreated at home, I have had some pretty large speakers and subs but never been able to recreate that live gig thump.
Is it primarily the resonant frequency of my chest cavity?
Frequency, amplitude?
Thanks in advance,
Keith

It is amplitude and power etc as others have said (and amplitude compression may temper it a little, but that is used live these days anyway to sound like an album, so it's probably minimal).

But there it is also the fact that the wavelength has time to pass over you in a larger space so that you feel the high/low pressure go past you, you are hit bu the "thump". The wavelength of 20Hz is 17m - there are not many home living spaces large enough to develop the full wavelength. In a small room it becomes "pressure loaded" at LF, so the whole pressure in the room goes up and down (apart from modal problems), there is no wavefront passing you to "thump".

It is possible (but highly inconvenient and unlikely) to recreate the effect in a home environment, ambisonics and wavefield synthesis do this - not that there's much material to play! Basically, 4 subs in an ambisonic setup (2 front 2 rear) will attempt to reproduce the LF wavefront with the front 2 subs "pushing" and the rear 2 "pulling". I've had it work reasonably well in a large VR environment, but it's not likely to be viable for home use.

 

[watchnerd]

I just got back from the symphony.

Suzuki conducting Mozart's "Requiem".

I didn't feel any chest thumping.

My home system has a little.

Guess I need to dial the subs down.

 

[Kvalsvoll]

‘Chest thump’ at live gigs, can it be recreated at home, I have had some pretty large speakers and subs but never been able to recreate that live gig thump.
Is it primarily the resonant frequency of my chest cavity?
Frequency, amplitude?
Thanks in advance,
Keith

Yes, it can. How do you want it?

A subtle kick does not require a huge bass-system, but the solid, gut-punching and heart-stopping impact requires the real thing, and you have to turn up the volume.

But once you experience this - a system that really feels like it does damage to your body - the novelty kind of wears off. Turn it down a bit, tune the system more towards neutrality, and you experience that bass with a nice, subtle tactile feel combined with definition makes the music experience so much better.

A good system delivers nuanced tactile feel, where huge drums feels different from kick drums, and even a snare will have some sharp tactile force.

A starting point is to tune the system properly, and you need decent speakers. Reasonably flat frequency response and flat phase/GD, experiment with listening position.

 

[MediumRare]

I’m working on it. My Velodyne DD-18 sub can get there, but resonances are a problem (furniture, windows). 2 subs would be better. The room is 22 x 40 with a complex dormered ceiling. I have to adjust the sub level for each recording; the mastering of sub 60 HZ content varies dramatically; so many rock albums have very little. New ones are much better in that regard.

 

[MediumRare]

*experiments with thump.

Will return shortly...

---

Well, that convinced me it is time to call the local electric utility again, experiencing low line voltage, as occurred a few years ago, prompting a curbside transformer replacement.

How could you tell?

 

[MediumRare]

But once you experience this - a system that really feels like it does damage to your body - the novelty kind of wears off. Turn it down a bit, tune the system more towards neutrality, and you experience that bass with a nice, subtle tactile feel combined with definition makes the music experience so much better.

Slam can be fatiguing, but when you want it and can have it, it gets you that much closer to the emotion of a live experience. And the at home sound can be "better than live" in some ways due to a clean upper end and the precise soundstage that doesn’t exist in an amplified live setting.

 

[DownUnderGazza]

Apologies if anyone's already answered this...

A few things I do to get that chest THUMP at Live gigs:
-- run your subs at about 10dB hotter (ie. louder) than your main Front of House FoH) speaker array.
-- put a moderately narrow-Q parametric EQ boost (Q<=1.0) at or around 80hz, vary the boost to get the maximum thump for minimum effort, 3-6dB is usually more than sufficient
-- high pass the subs slightly above their -3dB roll-off point to get rid of the major problem area of all vented / ported / scooped etc subs.

Feel free to modify your in-room 'House' EQ curve to re-create this 'Live' experience at home...

That 'major problem area' I mentioned?
Below a sub's -3dB point, the output from the port/vent/scoop is out-of-phase with the main signal (it cancels out the actual signal), causing a 24dB/octave roll-off; the driver is 'undamped' due to zero internal pressure within the cabinet for the driver to 'bounce' off, causing the driver to flap uncontrollably and heavily distort... unpleasant to say the least. Also, any amplifier power spent in that sub-bass region is therefore lost and wasted. Best to remove the problem area altogether.

 

[MediumRare]

Having watched many CDs play, the preponderance of them (at least the ones to which I listen), are rolled off on the low end.

New ones, not as much.

Jethro Tull - Benefit - just because that's what was playing, one channel from the CD player analog outs:

View attachment 36582

Daft Punk Random - Access Memories:

View attachment 36583

Hey, we be thumpin' now...

So, do you accept what the mastering engineer gave you or do you work the EQ?

 

[Dj7675]

Live sound chest thump ... I didn’t understand what people were talking about. Last year we went to a concert of Sunny Sweeney, Ward Davis, and Tennessee Jet. The venue was small, held around 150 people I think (Dante’s in Portland). Tennessee Jet (whom I never heard of) opened. He had no band, just himself playing guitar, kick drum, harmonica and singing. When he hit the kick drum, I could feel it literally hit you and rattle your insides. What was interesting was overall the sound was loud wasn’t the kind of loud that was too loud (for example I often wear earplugs). About half way through his first song, I turned to my wife and said “My hair is moving!”. It is an interesting sensation for sure. Seems to be more of a pretty big boost in the 50-100hz range. I have played with eq on my B460 JBL sub (JBL2245 18 inch driver) with an XLS1502 and it can provide that kind of tactile bass although I don’t have it set like that very often.

 

[MediumRare]

A few things I do to get that chest THUMP at Live gigs:
-- run your subs at about 10dB hotter (ie. louder) than your main Front of House FoH) speaker array.
-- put a moderately narrow-Q parametric EQ boost (Q<=1.0) at or around 80hz, vary the boost to get the maximum thump for minimum effort, 3-6dB is usually more than sufficient
-- high pass the subs slightly above their -3dB roll-off point to get rid of the major problem area of all vented / ported / scooped etc subs.

My sub is sealed, so no problem there.

Interesting your view is the "thump" (is that the same as "slam"?) Is centered around 80 Hz. If so, any good speaker can reproduce that wavelength; the issue might be how to get the volume of air moving from smaller drivers.

 

[GrimSurfer]

the issue might be how to get the volume of air moving from smaller drivers.

That is the exact issue subs are designed to address.

 

[DownUnderGazza]

My sub is sealed, so no problem there.

Interesting your view is the "thump" (is that the same as "slam"?) Is centered around 80 Hz. If so, any good speaker can reproduce that wavelength; the issue might be how to get the volume of air moving from smaller drivers.

First off, congrats on opting for a sealed sub!! For critical listening there isn't a better choice!

Thump, slam, sorry I prefer to avoid untrustworthy subjective commentary...
But, yes, in the pro arena, it really is as simple as finding the "I can feel it in my chest" zone and giving it a nudge.

As for smaller drivers, given that the low bass region is ALL about moving air, then small drivers are really going to struggle.
At home I use stereo 12" sealed subs, +/-1" excursion drivers, Linkwitz transformed to blend with room gain (giving a net -10dB @ 10hz) and Dirac correction to ensure correct timing.
For live gigs, it's all about multiple 18" subs to move air!

 

[MediumRare]

I found this exchange relevant and interesting. https://forum.audiogon.com/discussions/quot-slam-quot-what-is-it-is-it-really-accurate

 

[DownUnderGazza]

A side thought...

At home, for me, it's all about accuracy. Accurate frequency and phase responses and a gentle 1dB/octave downward tilt from 20hz to 20khz. No, I don't artificially tune for that live chest thump, I prefer to let the musicians (and mastering engineer) display their craft as they intended.

In a live gig situation, it's all about the emotion. Producing the 'feels' for all parties the best way I know how.

So I will high-pass, low-pass, manufacture an artificial bass 'thump', EQ the crap out of mics and instruments or into them to get a result that helps both the musicians and fans get into the 'zone' and lose themselves in the performance.

Yes, you read that right! Pro-engineers use 'TONE' controls, oh and DSP effects and correction if available.

Why? Because nothing satisfies more than an event that goes 'off'... where the performers glow with satisfaction and pride at the music they have created and the fans buzzing so much they don't want to leave, oh, and yelling to all and sundry how "Frigging AWESOME" that all was...

Yep, the simple things in life!

PS. I wonder if the purist home audiophile has any idea just how much pro-audio engineers f*_k with their pristine musical source way before it gets to their precious t/t's, DACs, Tubes, crazy-wire, and dinosaur passive cross-over loudspeakers.

 

[beefkabob]

Get a big sub and turn up the bass, beotch!

 

[RayDunzl]

So, do you accept what the mastering engineer gave you or do you work the EQ?

Master EQ and let the chips fall where they may on individual recordings.

 

[RayDunzl]

How could you tell?

Low Voltage alarm on a power strip, 108V input to the Equitech, and possibly some bass crackle - Victor's bass doesn't crackle...