Giant Sub-Woofer

PuceBaboon sent us linkage to an amusing story about building a gigantic custom sub woofer. I was about to yawn until I looked at the pictures of them excavating a 60 cubic meter hole, and laying bricks. This one might be a little outside the realm of reasonable, but it's damn impressive.

Not Worth It

[Doesn't_Comment_Code]

I've built my own speakers before, and while you can do a good-enough job without too much hassle, making a first-rate product is very labor and math intensive. If this guy is putting that much money and effort into this project, I really hope he gets all the damping and power equations right. Otherwise this will all just be a publicity stunt (maybe that's what it is anyway). I'm thinking about the amplifier he needs to run it right now. That's a lot of juice! And juice = money. And worste of all, you'd never be able to use the thing! Even a store bought stereo goes well above the municipal noice ordinances. And bass carries the furthest! What is this guy thinking?

If he ever does use it, I bet he'll feel that really cool thumping sensation in his chest though.

Blown Speaker?

[ryanw]

So what happends when this guy blows a subwoofer speaker? He has the speakers under 1 ton of marble if I read it right. That's not a very accessible configuration for maintenence.

Broken english, but...

[The Famous Brett Wat]

Walls and ceiling seems to fall down, but don't. The sound pressure is concentrated at the listening point and stopped by a 2 meters high woolglass anechoic wall on the back of the listening position.

Would you dare sit at this listening point? Is this where the Spanish Inquisition positions the comfy chair?

Re:Blown Speaker?

[ravind]

The question is, if he blows one, will anyone notice :)

Anyway if you had looked at the pictures, the speakers are easily accessed through a removable floor panel. Similar to the wiring in a server room.

Why is it that people look at a project, which someone else has put a ton of time and effort into, and think they can find flaws in less than a minute. Is your opinion of your fellow man that low, or your opinion of yourself that inflated?

Biggest *Enclosure* not biggest Sub

[Null_Packet]

I hate to nit-pick, but it's a large, elaborate enclosure and not a huge subwoofer itself. Slightly more practical is the "Cult of the Infinitely Baffled".

http://home.comcast.net/~ttriff//page2IB-Gallery .h tml

Re:bigger isn't always better

[nattt]

It's a horn. A horn is an acoustic transformer, which matches the impedence of the cone to the impedence of the air, giving a very effecient energy transfer. That means very, very fast bass, with more attack than any brute force method you describe. Your speakers are the equivalent of hitting a feather (the light air) with a golf club (heavy cone). The feather won't go far as there's a big impedence mis-match. The horn gradually makes the air the cone is trying to move match with the weight of the cone, so to speak, like replacing the feather with a golf ball in the above analogy. When the cone moves the air now, it moves easily because of the matched impedence.

To give you an example, my small horn speakers with a 7.5 watt amp go as loud as my brother's PA speakers on his 750watt amp. Do the logarithms and that means that my speakers are 20db more sensitive than his - because of the horns! (actually about 6db of that is due to bigger magnets, but the rest of the increase is down to the horns)

So, the end result is many, many times superiour, with louder sound, with less distortion than your "box" speakers.

Re:The "Biggest"

[Anonymous Coward]

You, sir, are a perfect example of why electrical engineers don't always make great audio engineers.

Hi-fi audio is all about vibrating air to sound "like" a real performance. If all you think about is the electronics, you are forgetting about the physical properties of the chosen speaker, the way the cabinet affects those properties, the accoustics of room, the precision of human hearing, and the subjective perception of the listener. Audio design is a discipline which demands that one think about not only electronics (although electronics are important), but wave physics, biology, and psychology.

Re:bigger isn't always better

[dfghjk]

Horn don't result in "faster bass". That's an absurd concept, as frequencies only "travel" as fast as they need to. Transients include high frequency components that aren't handled by the subwoofer. The original poster didn't know what he was talking about but you didn't do any better.

Horns do indeed provide great efficiency benefits as well as vastly improved harmonic distortion, but overall they do not exhibit less distortion that "box" speakers. Horns have terrible directivity issues and have very poor frequency response. In this much more important measure of distortion horns don't measure up. For high volume applications horns are desirable and are commonly used, but for near field listening they blow.

Re:I'm not an expert...

[dfghjk]

I wouldn't say that any true audiophile would rather have the tube. I've heard a one or two good tube amps in my day along with a few bad ones, but nothing touches my Levinsons. I'm certain there is other good equipment but I'm also certain that solid state is competitive with tubes.

It also doesn't matter what you listen to. Absolute fidelity should be the goal every step of the way and my experience is that "audiophile" equipment frequently fails to measure up to that ideal. This is especially true of equipment that needs certain musical forms to "appreciate" it.

Re:bigger isn't always better

[Anonymous Coward]

Electrostats and magnetic planar speakers couple to the air with thin membranes.

Much better than cones.

Re:The "Biggest"

[Anonymous Coward]

"Heh, um... if you are in a recording situation... the only use headphones have is for tracking/monitoring. Doing a mix or mastering using headphones? Um, no. Not in a million years :)"

Not really true.

I used to produce professionally for the BBC and several record lables and I would say that the art of mastering often relies on headphones a lot.
The _real_ art to monitoring is to realise that no single source can give you the true picture, and therefore a good producer listens to the work through several sources. Usually these are

1) Nearfields
2) Main studio mons
3) Tranny (a crappy mono transistor radio at the other side of the room)
4) Cans (standard headphones DT100 etc)
5) Monitor cans ( $500+ Beyers or AKGs)

Often there is a switch on the desk to select each of these monitoring sources, and you will see a good producer flipping furiously between them during a mastering sesh. The headphones are essential for guaging the ambience in the mix without room colouration.

Additionally it depends how well the producer 'knows' the sources. I have personally mastered tracks ONLY on cans which went on to be RAP award winning chart pieces.