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Comment by bob1029 | Hacker News Reader

I've been chasing infrasonic ranges in home audio for over 2 decades. You can't "detect" these frequencies in the normal way. You experience them by way of your physical environment being excited by them. Feeling pressure waves move through whatever you are standing/sitting on can add an entire new dimension to the experience.

I used to run experiments with friends and family using a 800L ported subwoofer tuned to ~13Hz with a 40Hz cutoff. Not one person would mistake it for being on vs off. Certain content makes these frequencies substantially more obvious. Classical music performed in large concert halls is one surprising candidate outside of Mission Impossible scenes. Being able to "feel" the original auditorium in your listening room is a very cool effect to me.

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I'm perhaps dating myself a bit, but I remember being caught off guard the first time I walked onto the dancefloor at Fabric (a famous nightclub in London). They'd put mechanical transducers under the floorboards and hooked them up to the audio feed, effectively turning the entire dancefloor into one giant subwoofer. [1]

It was absolutely a gimmick, but a tremendously well-executed one. Being literally lifted a few millimeters into the air when the bass dropped was such a visceral experience that I'm still surprised it wasn't widely copied in other venues.

[1] https://youtu.be/ijwxsIV8Iac?t=100

The first time I ever took MDMA was in Fabric many years ago. John Digweed was playing. I will never forget the sound and the feeling of that dance floor.

~2010 worked in Farringdon and this was our local club. Went in Fridays after the pub. Once took a holiday to cycle tour Romania, ran in to Romania's most famous DJ in a ski resort, and he told me his dream was to play there. Almost choked on my beer...

Well? Did he? :D

You can get a similar effect with a floating or semi-floating floor and a huge sub hanging from the ceiling. You have to tune it though.

If you are on the Bay Area, The Great Northern had a setup like that on the hallway at the entrance before the main floor. They use VOID for their soundsystem but I don't think that particular part of the setup is COTS.

they actually had to turn down that system for being too loud. but at that level, none of the stuff is really COTS because it requires a ton of tuning due to each particular venue's layout and acoustics

Damn. Consider myself pretty into sound but have never heard COTS and Googling was less than successful :(

Commercial Off-The-Shelf.

As opposed to some custom solution.

Not audio specific, if that helps

The Void gear is COTS including the Powersoft amps they use. You can set it up and it will work and it will sound amazing.

But once you have Void’s guy out to tune it to your space? The sound blows you away. I think that guy has one of the most fun jobs I’ve ever seen.

I don't think the subs hanging from the ceiling on the hallway in front of the bar are COTS. If they are it's not on their websites or catalogues. Like it may be the same cone but it's not the same enclosure or anchoring.

Fabric is still going strong! I've never really noticed the effect of the floor that strongly though.

Dance music is definitely a lot better when the music is loud enough for you to feel the beat on your face and clothes.

Wow this brought back a memory of that place I'd completely forgotten! Thanks! Haha

> I'm perhaps dating myself a bit, but I remember being caught off guard the first time I walked onto the dancefloor at Fabric (a famous nightclub in London). They'd put mechanical transducers under the floorboards and hooked them up to the audio feed, effectively turning the entire dancefloor into one giant subwoofer. [1]

I'm dating myself too by saying I always wanted to go to Plastic people back in those days and hear Youngsta dropping dubplates on SLs on a Funktion one system in such a tight room(s), but I had to settle for blowing out subs at 96kbps on pirate Radio (RinseFM) for many years until I finally got to seem him in the US with a Funktion One at Servante's and then the Blackbox in Denver, and a few more times at other venues on subpar sound-systems which didn't have the same effect.

Crazy stuff happened at Plastic People, so many crazy stories from residents to one-nighter bedroom DJ appearences made it sound like the holy grail of the Underground British Bass Music scene. That and I was still in my 20s, which will always add an extra glorified lens to anything.

I will definitely say something takes over at those sub-bass frequencies (20hrtz) on a proper system, it goes through your body and makes people go crazy on the dancefloor. Pinch articulated it best in my opinion [0]. I met him at a small venue in Hollywood where no one but me knew at the that hour know who he was and we had a really interesting about his label and music in general before his set along the lines of that interview around the same time, he is an incredibly smart person: he even dropped a dubplate (DS - Memory loss VIP) for me and was even kind enough to rewind as it went off!

0: https://www.youtube.com/watch?v=lXZ1k3nreo0

I enjoy seeing some heads on HN :) Hello from NYC! Had dreams of going to Plastic, RIP: https://soundcloud.com/floatingpoints/floating-points-four-t...

Tsunami is another good system in the US, unsure if they've been doing stuff since quarantine closed everything up. Analog in Brooklyn had a pretty wild SBS Slammer setup, but an ownership snafu caused that go away after only a couple years. Nowadays' indoors setup is the best in NYC for me – Randomer blows the lid off once or twice a year. This was him in 2019: https://imgur.com/a/ACocI87

> I enjoy seeing some heads on HN :) Hello from NYC! Had dreams of going to Plastic, RIP

Easy!

I think we all did back then, we were the outsiders looking in and that was Mecca; I started listening in 2006 when Youngsta's Dubstep All Stars came out so to us it was pretty rare thing that few out of LND had ever heard of, but we eventually had nights in CA. It was mainly brostep noise, with the occasional UK talent if you were willing to drive on a weekday to LA and drop lots of money, which I didn't have at all back then. But I saw Distance back in 2009 at the Roxy on a weekday and went to work and slept in the parking lot for a few hours after the rave just to see him, but I finally got to hear his remix of Changes and then Beyond on a decent rig and just went into some eyes down thing, and which made it all worth it.

So, when that wasn't possible I stuck to pissing off my neighbors with my paltry bedroom DJ antics on vinyl I had shipped from Redeye every 2 months from London and listening to RinseFM to fill the void.

NYC? Isn't Joe Nice still doing/running things out there?

I know the Dub Warz nights were the US' version of DMZ for a while, and was sort of a soundclash [1] theme to it, right? I saw some footage of Kahn at one and the dubplates he was pulling out during his set were insane.

I've been out of the scene for a while now, last event was before COVID (late 2018 or early 2019) where I was convincing Youngsta to get SP:MC to Denver since Nicole repped'd so much talent and SP;MC is badman (MC/DJ/Producer), which he did later in the year but I couldn't make it out.

I still can't believe Toast bigged me up at a rave ahead of Leon Switch's set when I told him I was part of the original Thursday night 'brandy and bass' crew as he was walking up to the stage and I was talking to Leon, which for those of who listened from the US back then seemed impossible but they were just normal lads happy to see people came. I asked him if he could drop The Fifth VIP, and when it dropped I ran up to the booth from the dance floor trigger fingers in the air and we both had smiles ear to ear (reminding me of this [0]).

Apparently he started including that track in his sets from then on.

Good times!

I'll send you pic of my signed copy Surge/Cold Blooded when I get back to the US. I got it when I met Youngsta a few years after it got pressed. I used to hang it on my wall above my decks, you're probably the only one HN that would even know who that is let alone appreciate the golden era we were going through back then--talent from DnB and Dubstep were crossing over so much back then and that was the when the genre felt so free and open to explore what it wanted to be.

Leaving you with this one, as I just fired up the sub and will be signing out with this [2] tonight with a spliff.

0: https://youtu.be/-HvqRzshkrg

1: https://youtu.be/ElXYoyfL-RM

2: https://www.youtube.com/watch?v=XX378lVkfIU

man those bring me back. cheers

> man those bring me back. cheers

Safe, those were fun times, but if you really want a step back into time check this one out [0], all that talent in the BBC studio with MAH was in insane. I remember that picture they took floating around back on DSF, too!

I bagged a few Loxy and Resound VIPs on wax last night (CLS001/INV:LOS) as I was having such a good time remembering all those nights. I'm glad to see others enjoyed those days, too. I tend to forget how much Stella sessions influenced my mixing until I remember what Skream used to sound like back then, I learned how to vary up my track selection and mix down-transition not from Distance or Youngsta (both were way too talented for me) but from Skream which is way more raw.

Something about hearing Mud into Ruffage (with the crowd shelling) makes me feel like I'm back in those dark rooms; Skream and Distance look so young in that video it almost makes you think in there right mind gave them that can of red stripe! And since I'm about the same age as Skream, it makes it even more nostalgic.

I remembered that a kid from Scandinavia (Sarsy) who was too young to be there back then but loved those days searched all over the internet and pieced together a bunch of Kryptic Minds dubplates from radio shows or otu at clubs on ableton on uploaded them over the years on soundcloud [1], now that was dedication!

0: https://www.youtube.com/watch?v=b_wmgpQO6iQ

1: https://soundcloud.com/thesarsy

This one's a favorite of mine, thank for the reminder. Also, you know what brings me back? There's an old computer music production video with El-B Ghost showing off his setup and breaking down his production notes on a track [0]. It's amazing how someone who's not big on computer and technology can figure out everything they need through sheer intellectual brute force and determination.

For a minute there I could not get enough Skream, Loefah, Caspa, Appleblim, Boxcutter. I still listen to them, but it's hard to reconcile that a lot of the original pioneers have moved on. There's a new sound now, more of a wobble - check out mixes from JVIZ and his podcast called JVIZ Presents: Earthquake Weather. It's still new generation dubstep, but it's more roots oriented, and has a fresh out the basement feel to it. [1]

Checking out Sarsy now, thanks!

0: https://www.youtube.com/watch?v=QUtE3v_Gd8Q

1: https://www.jviz.net/archives/

> I still listen to them, but it's hard to reconcile that a lot of the original pioneers have moved on. There's a new sound now, more of a wobble - check out mixes from JVIZ and his podcast called JVIZ Presents: Earthquake Weather. It's still new generation dubstep, but it's more roots oriented, and has a fresh out the basement feel to it. [1]

I guess it really depends where you are in the US, because when I'm in the US I'm mainly in CO and this kind of set happens (Kahn and Neek) in Denver on a Tuesday nights [0] or half of Mystic State dropping 140 [1] like it was a night in London (prefect example of this thread @ 1:00 mark) because of how healthy the scene/community is thanks to Nicole and Sub.Mission. It's come a long way from the aggro-brostep noise that it was back when it first came to the US!

I think the sound progressed so much from the early days; but for me 2008-14 were the real glory days with so much talent and collabs from DnB/Dubstep/Grime/Purple etc... It also helped I had actually been working in Europe most of that time so I got to go to some raves in the EU/UK whenever I had the chance.

It's been a while since I've been to a 140/170 night since COVID messed up everything, but I'm glad to see it's back. Denver really was/is like a mini-London time capsule of that era and sound so if you can make it out to a night to re-live some of those nights, the system in the mainroom is RC1 spec and sound-management are a bunch of heads, and the bar/mezzanine room usually has DnB nights (ReCon) with a more tamed system but still a good spot to rave.

I'll drop you a line when I'm back state-side and we can try and go rave in Denver.

0: https://www.youtube.com/watch?v=1NMiZDTI0BA

1: https://www.youtube.com/watch?v=ft8FbtCqZvE

Sounds good to me :) I'm in a rural area, it's all lagged behind by a few generations out here, so the denver scene is probably insane compared to what we have. By the time it got to us, Borgore and Rusko were having their time, but -every- once in a while, you'd catch a 'dubstep' track download that had a distinctly different sound that didn't leave your ears ringing, it left my soul ringing, and rattled the keyboard right off the desk. That's when I knew I found the right stuff. I think the first one that comes to mind was Loefah.

Btw Sarsy was a great recommendation.

reading your comments brings back memories of the good ole days..Denver still has the best scene in the US. the Midwest holds it down too but its slowed down in recent years, except for infrasound which is always worth the trip out. ill never forget seeing Quest in the basement of a bookstore in downtown Minneapolis when i was randomly there many years ago. I'd love to go to the UK to see some shows, your lucky to have been there. recently, the youngsta, ntype, hatcha project Trilogy has got me wanting to hop on a plane. speaking of ntype, he's got some US shows in a few weeks.. some day id really like to send it to Outlook too. the brostep movement is fading, or atleast from my perspective it is, can't say I didn't partake back in the day, but I grew out of that fad pretty quick. however I will say, the loudest show I've ever been to was excision in Madison Wisconsin the first year he toured with the 100k Watt PK rig, before his style got really out of hand. to this day I haven't felt my insides vibrate like that again..unsettling to say the least

Plastic People (Oxford Street or Shoreditch) was indeed an amazing experience. I went a lot. But its soundsystem was not quite on the same level as Fabric’s or The Ends - those two both seemed to have the sound system more integrated with the rooms design with huge reserves of power so everything was crystal clear and no ringing ears afterwards.

PP did have a better sound system than 99% of clubs I have been to around the world though - it was no slouch.

The End's sound system is the best I've ever experienced, I'd love to know how they set it up.

big ups to the bass heads of HN!

I wonder why this isn’t in every high end nightclub.

Most club owners will not spend half to two thirds of their budget on room acoustics and speakers. They build an expensive looking bar and VIP room instead.

> Most club owners will not spend half to two thirds of their budget on room acoustics and speakers. They build an expensive looking bar and VIP room instead.

It also is worth noting most people aren't really going to clubs just to listen to the music, so much as they are to socialize and drop money on booze. And I guess now to record themselves at an event for social media likes/marketing/influencer stuff.

I've seen far too many people having full blown conversations for 20+ mins on the dance floor over the years in other genres and could over hear their conversations and it was so off putting, where as with bass music their was an etiquette of going outdoors in the smoking area if that is what you wanted to do as the dance floor was for just that.

It's also worth noting when you step on to the dance floor with those heavy systems (Funktion One/RC1) and music optimized for those low sub-bass levels the whole place would shake [0] from the bass weight (bar included) so it was pointless to try and record anything worth showing if they all had these systems this way and only until recently have mics on phones been good enough to get anything but boomy noise.

0: https://www.youtube.com/watch?v=9_f-hKslYkA

It doesn’t seem clear that ‘an expensive looking bar and VIP room’ will always generate more profit then speaker floors.

It wasn't so good for drum and bass, there's so much bass already that it used to turn the bass sound into a mushy mess, if you ask me.

The issue with those ultra-deep frequencies is that the waves become really long and the acoustics to make them behave become increasingly unwieldy the lower you go.

Dampening a the 9.8 meter long wave of a 35 Hz tone is already hard, dampening a ~19 meter long 18Hz wave mist be pretty much impossible.

The only thing more amazing than loud low bass is bone dry loud low bass that starts and stops precisely.

    The only thing more amazing than loud low bass is bone dry loud low bass

Bone dry sounds awesome.

My frustration with rock venues is that there's usually lots of bass, but it's super sloppy. Everything below ~80hz sounds like a giant audio sludgeball.

I feel like even a little bit of tuning and room correction (the sort one can do at home with freeware and a $89 calibrated microphone) would help tremendously, but there's no appetite for that on the part of concertgoers or sound techs.

I'm glad there are dance venues getting this right.

That sounds like something I could do for my own loungeroom. I mean, I have no fancy gear but it seems like a process to make the best of what I have. For the cost of a decent microphone it could be worth it.

The gist of it is:

- get a calibrated mic

- use REW (Room EQ Wizard, free) to take several measurements in your room, in the listening area(s)

- REW will average them and generate an inverse EQ curve to compensate

- you can export the parametric EQ settings and use them anywhere that supports parameteric EQ such as EqualizerAPO (windows, free) or CoreAudio parametric EQ units (Mac, free) or in a standalone hardware device like the MiniDSP (~$100 IIRC)

you can always tweak the parametric EQ curve to suit your personal taste, like some extra bass or extra treble to compensate for aging ears (like mine)

have fun and good luck!

Wow, thanks for the quick writeup. I think I'll give this a shot at work where we have audio/video equipment for presentations and the like.

Good luck! Corporate meeting rooms tend to be a bit of a worst case scenario for sound.

The absolute worst case scenario for sound is an empty rectangular (or cube) shaped room with bare walls and most corporate meeting rooms come pretty close to this.

However, you can still make some improvements.

Yeah, foam deadening has gone a long way for us to reduce echo and other issues over Zoom, along with many directional mics condensed into a mixer. I am a bit of a stickler with sound quality over conference calls, so anything to improve it is very interesting to me.

REW is an excellent piece of software. You may be able to make some improvements for a single listing positioning, but just a heads up that you can't EQ away room level issues.

From their own (again excellent) help guide: https://www.roomeqwizard.com/help/help_en-GB/html/iseqtheans...

Right, REW is not a cure-all. Speaker selection and placement are orders of magnitude more important than anything else.

After that comes room issues. Surprisingly I think most residential rooms are decent, acoustically, because they tend to be filled with padded furniture and such and aren't overly reflective in obnoxious ways. Also most people aren't running massive subwoofers and if they are, they generally know what they're getting into. With all that said, I think REW is great for cleaning up the rest.

If all people did was pay attention to speaker selection and placement, I think most people would wind up with a very good listening situation.

And if all people did was pay attention to speaker selection and placement and clean up the remaining issues with REW, I think most people would wind up with a great listening experience.

Good starting tip, but readers should be aware that you can only help with frequency domain issues here.

The thing that might break your acoustics might more often be time-domain issues. No EQ on earth will get rid of the reverb in an empty warehouse. The same is true on a smaller scale in your place. And because it is smaller you will have specific frequencies (room modes) ringing out longer or shorter at your listening position. These are issues you can only fix with actual physical alteration of the space by putting in more stuff and adding absorbers, diffusors and such.

So EQs can help, but you should also think about the actual surfaces of the room itself.

In principle you can also use a phased array to remove the reverb. I'm not aware of any non-academic implementations though.

https://holoplot.com/ give a two dimensional array. The hangs of speakers that you see at most concerts are a line array, and within each of them will be an array of transducers that control the pattern of the individual cabinet (eg cardioid subs. You'll also quite see digitally steered columns in a lot of spaces these days too. None of these remove the reverb, but they do provide control over where energy is directed to minimise it occurring in the first place.

Neat! "All" you need on top of that for reverb cancellation is for the 2D array to be a surface enclosing the region of interest and for the way it itself mechanically interferes with the sound to be predictable. If you're a bit careful with where you send the sound then perhaps the top/bottom exits wouldn't matter too much.

Forgive me! It's a broad topic, and one must always choose what to cover in a short internet post.

In short I think speaker selection and placement are about an order of magnitude or two more important than everything else. If those are the only two things you pay attention to and don't drastically screw the rest up, you'll have a nice sounding system.

Room correction (which is also speaker correction) is probably the next most important thing, although well into optional territory IMO.

There's lots more that I fuss over, but I don't want people believing that they need a lot of elaborate rituals and room alterations to achieve good sound. It's not true, it's counterproductive, and scares people away from this really fun hobby. =)

    No EQ on earth will get rid of the reverb in an 
    empty warehouse. [...]

    So EQs can help, but you should also think 
    about the actual surfaces of the room itself.

You're completely correct, but I don't emphasize room issues too much for beginners. Why? In my experience, most residential rooms are actually pretty acoustically decent for a few reasons.

1. They tend to be filled with comfy padded furniture, bookshelves, etc. which do a nice job of breaking up high and mid frequency reflections.

2. The brain already performs a lot of "room correction" and it's particularly good at performing it in familiar spaces like our own homes.

3. Most people's home systems (especially those of beginners) aren't putting out the kind of massive low frequency output that's really troublesome to tame.

Of course there is always going to be a room mode or three, usually with a prominent one somewhere in the midbass range.

I have already played with EqualizerAPO in the past and it surprised me with how capable it was.

As you seem to have intuited, I am in beginner territory and that "gist of it" overview is all I needed.

My HTPC/Steam machine will get a calibration in the near future!

Thank you very much for helping me to help myself to improve listening experience.

Room correction rarely can get as good a result as actually sorting out the room, particularly at concert/club levels.

It sounds like you frequent some questionable venues. You'd be hard pressed to find many live sound engineers operating today that won't be working with a dual channel RTA (Smaart, or similar) and keeping an eye on the venue's transfer function during a gig as the acoustics change (different crowds, temperature etc).

Hey stemming from this is a lot of talk of eq and rooms. I hope no one minds but may I also add something for budding sound techs: mics and speakers and why it’s easier for a dance venue compared to a live rock venue. These are what I’d call newbie-ish problems so forgive me if you’re talking about pro level rock venues. Low end builds up on stage and unless managed gets into mics you don’t want it to leading to lots of sloppy bass. One might low cut mics that aren’t meant to be receiving low end content for example or mute ones not in use. Another thing is that producing bass frequencies requires the speaker diaphragm to move more air and so there’s a slower transient response or time to complete a cycle. If you send too many different things at once to the low end the poor thing gets ‘confused’ and things get sloppy. Double hangs seem to be getting quite popular for this reason, less instruments fighting over the same cycle. Otherwise don’t send everything you can to the sub just because you can. Personally, unless there’s some reason to, I rarely let anything go below 80 anyway and defs not 60. I hate giving advice, tell me how I’m wrong.

I'm curious, if these waves aren't heard, is there much need to dampen them? Are we talking about to reduce the physical effects on those around, or is there a mechanism that makes these audible at some point?

Without damping them you get a few problems around standing waves and room modes.

Those modes will make it so that you have some areas in the room where that frequency will be uncomfortably loud, and other areas where it goes away entirely.

The article is talking between 8 and 37hz, iirc. General given hearing range is 20hz to 20khz. So the vlf is flirting with that range. Throwing in an aside here, inaudible might be a better word than undetectable. I was always told just because you can’t hear it doesn’t mean you can’t feel it, for both high and low end. As for why you might want to dampen inaudible low end aside from a fastidious want for control, or not wanting a build up of that feeling only for some lucky punters, you might just not want to shake a ceiling tile loose or a vibrating air duct might be annoying: there is more energy in the low end.

Works at somewhere like Burning Man where there's little to have standing waves against.

This is one of the factors that make decently large, remote outdoor electronic events (bush doofs etc) such an experience. There's no better way to enjoy the tranquil surrounds of nature than slapping a giant Funktion One system into it.

Where do you get your recordings from?

It bums me out that most music recording and reproduction equipment drop off drastically outside 20-20,000hz. I wish that we could open that range up a bit more, the low end for haptics and the high end for the other beings in our house that can hear in that range (dogs, cats, etc)

The new amplifiers from Purifi are incredible when it comes to delivering a flat response to 0hz, at high power into complex loads.

I’m curious to see if I’ll be able to tell a difference in how their amps coupled with their new power supplies drive my ButtKickers :)

I wonder if you could just transpose the lower end, say 20-30 hz down to the 10-20 hz range since you can't hear them anyway so it won't sound bad, but you would "feel" it.

That’s what subharmonic generators do and I’ve heard mixed reviews.

Like, if you were to take the bottom octave of a piano pieces and replicate it on the next octave down, it could easily sound like crap. Might sound decent for some songs though?

I've got a lot of classical SACD and DSD recordings from many moons ago that were mastered very well.

You are right that you need to pay attention to the entire signal chain. A bad DSP or DAC somewhere in the middle will make your quarter ton of LFE completely worthless.

It's not even necessity a "bad" device. Sometimes circuit designers add a DC blocking capacitor on an input to avoid damage to the equipment (especially in an high powered analog amp you might want to avoid feeding DC into the speaker).

The digital domain is much more forgiving; reason why I preach going all-digital up until I2S into the class-d amp IC :) (No, I don't do that at home due to lack of available equipment - I'm still fully analog after the DSP/DAC combo).

One producer: Dillinja [0]

[0] https://www.discogs.com/artist/315-Dillinja

Reading the article, his track "30hz" was the first thing that came to mind. :)

Rocket launches must have so much of these frequencies. Being at one was nothing like I expected after listening to the audio of launches on normal devices.

> Rocket launches must have so much of these frequencies. Being at one was nothing like I expected after listening to the audio of launches on normal devices.

Agreed, I've been to lots of clubs and listened to heavy bass music most of my adult life. Launches are still indescribable and it just put an instant smile on my face and still gives me goosebumps after all these years as I wasn't even that close to the launch site (bluffs about 10 miles away): I saw the Falcon 9 launch at Vandenburg that made people think the aliens arrived [0].

0: https://www.youtube.com/watch?v=UVi01wACopc

As a music producer I've been ranting for a while now about how a lot of modern music cuts low end out in order to be louder on mobile devices and on streaming services like Spotify...

It's also been reported that the algorithms on sites like Spotify favor music that has less low end on it (especially pop songs), which only encourages this trend of loudness.

I've found that sub frequencies are also a good anchor for preventing music from being turned up too loud into areas where ear damage occurs... At live events in the past I've frequently had to wear ear plugs (or rolled up tissues in my ears if I forgot plugs) in order to protect my hearing from the trend of louder music composition.

In all of our music, I usually tune low end frequencies to create bass pressure that can only be felt on excellent sound systems, this is also likely why our spotify stream numbers have been low for years now, despite us doing well in places like audiomack and YouTube (where bass music aficionados are more likely to go for music...

I've long wondered about skipping the speaker and just going for a method to create long-waves to vibrate everyday environments. In sync after tuning it could be like a 360 earthquake internally.

If it works for microphones to catch radiant sound (as I learned in on-set film production) then it probably works the other way too (as I learned when in the booth watching a DJ friend plugged his headphones into the mic jack and used one earpiece to talk to the crowd).

You’re looking for rotary subwoofers [0]. They vibrate the whole room.

[0]: https://en.m.wikipedia.org/wiki/Rotary_woofer

This explains why the scene in Jurassic park never lives up to the expectations of watching it in my friend's home theater when I was a kid.

Let me introduce you to...the buttkicker: https://thebuttkicker.com

Interesting. They also have flight simulation among the applications, which made me recall an old family friend who was a passenger airline pilot during the 70s and 80s. He also played a bit with older Flight Simulator versions, and one time he commented "yeah, it's very accurate but it can't be the real thing: you don't just pilot with the instruments, you also need to feel the airplane with your ass".

That's not just vibration but also (and maybe more significantly) G forces.

Need a butt swinger for that: https://www.youtube.com/watch?v=KW-ONbO5NYU

They're pretty common in more expensive sim-racing rigs too. I wish I could add some to mine, but I've read online that it will be perceptible to the downstairs neighbors without a lot of floor damping.

Child’s play. Let me introduce you to the BOSS platform:

https://www.avsforum.com/threads/the-hideaway-theater.299152...

HT enthusiasts are crazy about this stuff:

https://www.avsforum.com/threads/the-tactile-response-thread...

Eight 18” subwoofers in the demo video at the start of this thread, and that’s one of the smaller setups.

https://www.avsforum.com/threads/show-us-your-tactile-bass-c...

Here’s what 6 hz looks like from a video from that thread.

https://www.youtube.com/watch?v=agSaMJ_H7VE

There was this DIY design I came across decades ago that I've been trying to re-find for years. It had 4 12-15" cheap paper cone woofers mounted 2 sets of face to face with both sets axially loaded and wired so that all 4 cones move together. The whole thing was put in a big loaf of bread shaped box and then some kind of bandpass something and vents to the outside. It was reportedly very good for this low low base stuff, not so good for higher end responsive bass stuff. Anyone have any pointers for where to look?

Maybe you’re referring to an infinite baffle setup like this:

https://jonathanfoulkes.com/ibsub

https://ibsubwoofers.proboards.com/board/13/builders-gallery

I'm running a 30" woofer in a ~2120L sealed enclosure. Changed the way I hear music.

... a sub the size of cube 128cm along one edge? nice.

I'll just leave this here:

https://en.m.wikipedia.org/wiki/Brown_note

> Classical music performed in large concert halls is one surprising candidate

Dumb question: what's emitting these frequencies in an orchestra?

I imagine it's the space itself resonating more than anything else, being excited by higher-frequency harmonics.

Instruments that play <= 40Hz (E1) include double bass (either standard or with C extension), bass clarinet, and contrabass clarinet.

Percussion also generates frequencies under 40Hz.

And percussion generates sharp transients, which require frequencies below the steady-state fundamental frequency to be reproduced accurately:

https://en.wikipedia.org/wiki/Uncertainty_principle#Signal_p...

Also octobasse and subcontrabass saxophone…although most people won’t get a chance to actually hear those in person.

Piano too if there is one. The fundamental frequency of the low A is 27.5Hz. A Bosendorfer Imperial grand piano goes down to C0, 16.4Hz.

If there's a pipe organ with 64' pipes you can hit 8Hz. Not many of those though.

Plenty of organs go below 20Hz though, and even an otherwise good sound system starts to struggle around 40Hz if it's not built specifically for playing such notes.

Dumb question but how is the piano capable of generating these frequencies? I thought the strings couldn't get nearly long enough and the low frequencies that you heard from piano were just psychoacoustics.

The bass strings are wound with copper wire so that the mass is much higher and the resonant frequency much lower.

The amount of space needed for a certain frequency in air is different to the length needed for that same frequency in a wire.

It might help to see the formula, which is:

Frequency = sqrt(tension/(mass / length)) / (2 * length)

So length, tension, and mass are all factors. Modern upright pianos also string the bass strings diagonally to give them a bit of extra length.

Having said all that, the same bass notes on longer pianos that can fit longer strings sound more sonorous. I'm not sure exactly why that is. For an extreme example see for instance the Alexander Piano[0], or the Klavins 370[1].

[0] https://youtu.be/PcP8UMgsmFo?t=132

[1] https://www.youtube.com/watch?v=LPGw-Va5xPU

I can almost imagine seeing the low bass string on the longest piano vibrating. The frequency is so low you can pick hear the peaks and valleys.

I'd say timpani drums, tubas, largest/lowest pipes on an organ (if the hall has one), and double bass. Contrabassoon, the lowest notes of a piano. Other percussion like a gong.

Basically, by necessity, whatever the largest instruments are in diameter or length. And then it's all being amplified by some mutual resonance with each other and possibly other physical structures like the floor.

> Being able to "feel" the original auditorium in your listening room is a very cool effect to me.

What do I need to buy to have this in my car?

Your car likely does not have enough volume to accommodate the required equipment. Just one of these subwoofers occupies the entire bed of a typical pickup truck. Two of these are used in my listening space.

The lower the loudspeaker goes, the bigger it needs to be.

You can at least partially trade width with depth, that is, making a speaker narrower but design it so that the cone can travel farther and move the same air volume, but it also have drawbacks, and thicker speakers are also harder to accomodate.

The smaller the volume of air you need to move, the less this matters (which is why IEMs have more bass than tiny bookshelf speakers, despite being way smaller. It should be theoretically possible to do just replace the trunk and backseat of a saloon and have a 2 seater with good bass extension

I think we are taking about the bass shaking your chest. IEMs can’t do that.

IEMs can develop high pressures at low frequencies because the volume of air they are moving is very small. A compact car with the windows rolled up here is analagous to the ear canal in the IEM. If 50% of the internal space of the car is speakers (easily achievable if you remove the backseats and use the trunk space), then you ought to be able to generate large pressures at low frequencies as long as the windows are rolled up.

I'm not sure that's entirely true/necessary. Standing waves in the cabin can help compensate a decent bit. A good transmission line speaker can likely fit in the boot/trunk, though stereo imaging will likely be poor in any car audio system I think.

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