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Unusual Speaker Designs

sarumbear

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Jim Rogers JR149 (1970s) - cylindrical aluminium enclosure


Zud1OeW.jpg
yb11_vin_jim%20rogers.jpg
I owned a pair. It’s basically a BBC LS3/5A in a cylindrical enclosure.
 

DanielT

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Killing with sound - reminds of of that great Kate Bush song.
Fascinating speaker:

What is it for?

Anyone who has witnessed a rocket launch is struck by the amount of noise produced by it – even when standing several kilometres from the launch pad. Of course a satellite on top of its launcher is exposed to much higher levels of acoustic noise. Long before it gets to that stage its designers have to test that the satellite can withstand such a sustained sound.

The largest European facility of its kind, ESA's Large European Acoustic Facility (LEAF) is a test chamber measuring 11 m wide by 9 m deep and 16.4 m high. Its walls are made of steel-reinforced concrete 0.5 m thick to contain the sound and are coated with a thick coating of epoxy resin to reduce noise absorption and increase internal reverberation.

What are its features?

The noise generation system consists of four different horns with low cut-off frequencies of respectively 25, 35, 80 and 160 hertz complemented by three high-frequency noise generators. A maximum overall noise level of up to 156 decibels can be achieved: provisions have been implemented to extend the level up to 158.5 decibels.

Wondering if there is a known speaker manufacturer that has been involved in that project? Anyone know anything about that? Otherwise, out of sheer curiosity, I see that the link contains contact information. I email and ask.

 
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pozz

pozz

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Fascinating speaker:

What is it for?

Anyone who has witnessed a rocket launch is struck by the amount of noise produced by it – even when standing several kilometres from the launch pad. Of course a satellite on top of its launcher is exposed to much higher levels of acoustic noise. Long before it gets to that stage its designers have to test that the satellite can withstand such a sustained sound.

The largest European facility of its kind, ESA's Large European Acoustic Facility (LEAF) is a test chamber measuring 11 m wide by 9 m deep and 16.4 m high. Its walls are made of steel-reinforced concrete 0.5 m thick to contain the sound and are coated with a thick coating of epoxy resin to reduce noise absorption and increase internal reverberation.


What are its features?

The noise generation system consists of four different horns with low cut-off frequencies of respectively 25, 35, 80 and 160 hertz complemented by three high-frequency noise generators. A maximum overall noise level of up to 156 decibels can be achieved: provisions have been implemented to extend the level up to 158.5 decibels.

Wondering if there is a known speaker manufacturer that has been involved in that project? Anyone know anything about that? Otherwise, out of sheer curiosity, I see that the link contains contact information. I email and ask.

@Tom Danley Do you have any comments? I think you did similar work at one point.
 

Killingbeans

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I'd probably go there the other half of the year. It's mostly the "more polar bears than humans"-thing that attracts me (and yeah, I know it's not true). Not that I have a desire to be eaten or anything :D
 

DanielT

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@Tom Danley Do you have any comments? I think you did similar work at one point.
Curiosity took over. Could not hold me. I emailed ESA. Asked a bit about the design and what type of amplifier they use.

I'll see if I get an answer. ESA receives many emails. If there is a detailed answer, I might start a new thread about it, if there is interest in that. :)
 

kyle_neuron

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Svalbard? One of the places I'd really like to visit.
Værøy, up in Lofoten. It's a six-hour ferry ride from Bodø airport. Tiny yet gorgeous place. Good spot for the Aurora borealis if you can stomach the cold in winter.

If you're feeling flush, I recommend the helicopter ride :)

B89F4243-D67C-4A91-9F4F-8F6AF1F51CAF.jpeg


Here are some other fun ones.

A 40-inch Powersoft M-Force linear motor subwoofer tuned to 17 Hz that a friend owns:
59936135-93E9-437B-A763-2B05477389DF.jpeg

The 180-degree wide, asymmetrical vertical coverage full-range SharcFin by Mr @Tom Danley:
87089250-B8CF-4D49-B35D-386C76499BD7.jpeg


I forget who makes this - it looks like a rejected Dr Who bad guy - but it led to some fun discussions:
E77B49AA-67D9-49FF-B1F6-0A2ECC96C21E.jpeg


And these very sexy "is wall" massive multiple-entry horns with 4 metre folded horns attached to the rear of the LF drivers. Probably a touch close to the Synergy patent for comfort, but I still covet them *hard*:
86BCD325-C1CA-4D2E-9F38-C9494C7868FF.jpeg
0CACB014-9F24-466F-9E0A-7E12FFFFB363.jpeg



Just saw the ESA stuff. I don't think that monster is using any manufacturers in particular, but NASA commissioned a portable version of that test via Maryland Sound. They use custom-built fully horn-loaded vertical arrays, mostly loaded with drivers from the B&C family of companies and driven with custom high-power Powersoft amplifiers.

blog_Orion-Speakers-High.jpg


Blog post: https://blogs.esa.int/orion/2019/05/31/solar-wings-installed-and-acoustic-testing/
There's a conference paper here:

I have lots of behind-the-scenes photos of the DFAT from someone who worked on it, but sadly can't share them.
 
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DanielT

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Værøy, up in Lofoten. It's a six-hour ferry ride from Bodø airport. Tiny yet gorgeous place. Good spot for the Aurora borealis if you can stomach the cold in winter.

If you're feeling flush, I recommend the helicopter ride :)

View attachment 158966

Here are some other fun ones.

A 40-inch Powersoft M-Force linear motor subwoofer tuned to 17 Hz that a friend owns:
View attachment 158967
The 180-degree wide, asymmetrical vertical coverage full-range SharcFin by Mr @Tom Danley:
View attachment 158968

I forget who makes this - it looks like a rejected Dr Who bad guy - but it led to some fun discussions:
View attachment 158969

And these very sexy "is wall" massive multiple-entry horns with 4 metre folded horns attached to the rear of the LF drivers. Probably a touch close to the Synergy patent for comfort, but I still covet them *hard*:
View attachment 158972View attachment 158973


Just saw the ESA stuff. I don't think that monster is using any manufacturers in particular, but NASA commissioned a portable version of that test via Maryland Sound. They use custom-built fully horn-loaded vertical arrays, mostly loaded with drivers from the B&C family of companies and driven with custom high-power Powersoft amplifiers.

blog_Orion-Speakers-High.jpg


Blog post: https://blogs.esa.int/orion/2019/05/31/solar-wings-installed-and-acoustic-testing/
There's a conference paper here:

I have lots of behind-the-scenes photos of the DFAT from someone who worked on it, but sadly can't share them.
Thanks for the information and the links regarding NASA and sound reproduction in those contexts! Very interesting. Incidentally, nice "regular" speakers in your thread as well.

There are well-designed horn speakers, but nowadays when it is still so cheap to get hold of many pure W in terms of amplifiers, they have more or less finished playing their role in Hifi, or maybe not?

Horn speakers, whatever you like about the sound and its size, they are at least damn masculine.:)
 
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sarumbear

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Fascinating speaker:

Wondering if there is a known speaker manufacturer that has been involved in that project? Anyone know anything about that? Otherwise, out of sheer curiosity, I see that the link contains contact information. I email and ask.

Let us use some simple math and logic.

Most speaker manufacturers use electromagnetic drive units. Best woofers can deliver 100dB SPL per Watt at 1 metre.

If you use a simple formula like here you will see that you need a 100kW amplifier to achieve that 150dB SPL. Having seen a drive unit one can understand that cooling the voice coil or create a magnet that contains the voice coil within the required Xmax is a tall order.

How about more drivers and use a nice juicy 18" JBL woofer? Technically possible but you need 150 of them each fed by a 600W amplifier at full blast.
 

mhardy6647

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Fascinating speaker:

What is it for?

Anyone who has witnessed a rocket launch is struck by the amount of noise produced by it – even when standing several kilometres from the launch pad. Of course a satellite on top of its launcher is exposed to much higher levels of acoustic noise. Long before it gets to that stage its designers have to test that the satellite can withstand such a sustained sound.

The largest European facility of its kind, ESA's Large European Acoustic Facility (LEAF) is a test chamber measuring 11 m wide by 9 m deep and 16.4 m high. Its walls are made of steel-reinforced concrete 0.5 m thick to contain the sound and are coated with a thick coating of epoxy resin to reduce noise absorption and increase internal reverberation.


What are its features?

The noise generation system consists of four different horns with low cut-off frequencies of respectively 25, 35, 80 and 160 hertz complemented by three high-frequency noise generators. A maximum overall noise level of up to 156 decibels can be achieved: provisions have been implemented to extend the level up to 158.5 decibels.

Wondering if there is a known speaker manufacturer that has been involved in that project? Anyone know anything about that? Otherwise, out of sheer curiosity, I see that the link contains contact information. I email and ask.

Reminds me of...
altec treble manifold or weapon.png

Those are lots of Altec treble drivers (288s, I reckon, although they look large even for 288s). :)
Despite the nerd glasses, I think I can detect a note of pure terror in that fellow's eyes...
 

mhardy6647

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I'll see if I get an answer. ESA receives many emails. If there is a detailed answer, I might start a new thread about it, if there is interest in that. :)
<emphasis added>
Yeah, but half of them are advertising extended car warranties, and most of the rest are for ED drugs. :cool:
 

Soniclife

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As for loud, this is the silliest thing I've done; this level was maintained with broadband pink noise at an average of seven mic positions for 30 minute periods, with 15 minute breaks, for ten hours.
Why? I'm kind of hoping the answer is 'because we could'.
 
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pozz

pozz

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Reminds me of...
View attachment 158983
Those are lots of Altec treble drivers (288s, I reckon, although they look large even for 288s). :)
Despite the nerd glasses, I think I can detect a note of pure terror in that fellow's eyes...
What was it used for? Do you know who designed it?
 

HammerSandwich

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If you use a simple formula like here you will see that you need a 100kW amplifier to achieve that 150dB SPL.
<snip>
How about more drivers and use a nice juicy 18" JBL woofer? Technically possible but you need 150 of them each fed by a 600W amplifier at full blast.
That conclusion ignores the efficiency boost from using multiple drivers. Which is a little weird, because the calculator you linked includes it.

Background for newbies: double the number of drivers, and you gain 3dB at the same input power. Easiest to consider that a pair of series drivers gives the same SPL as one driver at the same voltage, but current & power are halved because double the impedance.

So, 128x drivers nets 21dB gain. With 100dB/W drivers, use 1kW (+30dBW) to produce 150dB total. That's only 8W per driver.
 

Tom Danley

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@Tom Danley Do you have any comments? I think you did similar work at one point.
At Intersonics, we did make some very loud sound sources for research and our space flight hardware for the shuttle was subjected to acoustic and mechanical vibration torture tests. Rockets, even smaller ones are very loud. At 1/4 mile from a black Brant sounding rocket launch, think about a very close lightning strike and the impact of the thunder that goes with it....... except it doesn't stop it just gets quieter as it climbs.
More recently, we were asked to quote on two different test systems like this but neither turned into anything. One of them was pretty much impossible using normal drivers as the pressure needed was greater than the force on the cone that the drivers BL and current capacity could produce.
Hard to beat a fast chemical reaction for impressive sound that makes you feel scared
Tom
 

DanielT

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At Intersonics, we did make some very loud sound sources for research and our space flight hardware for the shuttle was subjected to acoustic and mechanical vibration torture tests.
Exciting! :)

Feel free to tell us a little more about it. How did you do? If you feel like telling a little more about it and if it is not classified, of course.
 

kyle_neuron

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That conclusion ignores the efficiency boost from using multiple drivers. Which is a little weird, because the calculator you linked includes it.

Background for newbies: double the number of drivers, and you gain 3dB at the same input power. Easiest to consider that a pair of series drivers gives the same SPL as one driver at the same voltage, but current & power are halved because double the impedance.

So, 128x drivers nets 21dB gain. With 100dB/W drivers, use 1kW (+30dBW) to produce 150dB total. That's only 8W per driver.
This conclusion ignores the massive loss of output from incoherent coupling effects :) having done it (on much shorter time frame and a fraction of the budget), it’s a lot harder than simple maths suggests. Even more so in direct - rather than diffuse - field radiation.

One major factor is the heating element. Not just on the components directly, but from the air itself.

Air itself also becomes nonlinear after a point. Not all of those harmonics are useful. Or easily predictable.

Why? I'm kind of hoping the answer is 'because we could'.
Same reason as NASA! Aerospace spec testing. I've also done some fun infrasound stuff. 130 dB long term at 12 Hz is good for the soul, but less good for the brain's cognitive abilities...

Unfortunately, the vast majority of this stuff is NDA’d to death, so I can’t share specific details.

I think one of Tom’s mentioned quotes is one I requested. It’s (still) pending budget review, but unlikely to proceed if only because of how ridiculous the job spec is.
 

antennaguru

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Here is a CONCRETE cabinet monitor speaker from Sweden, the Rauna Tyr II. It has a 5.25" woofer for scale and a cast CONCRETE cabinet that is extremely heavy for a small monitor speaker. The slip-over grill socks are off for the picture.

In this picture they are powered by a 20 wpc pure Class A audio amplifier deck I built that runs hot enough that you actually cannot touch the side heat sinks until five minutes after you turn the separate power supply off. The separate linear power supply is designed for continuous duty at 600 Watts AC input delivering +/- 35 VDC. I built the supply as a test-bed for use with a multitude of Audio Amplifier Decks I was building with different topologies.

Rauna Tyr II.jpg
 

antennaguru

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These 11.25 inch tall speaker cabinets are truly "Bookshelf Speakers", but what makes them unusual is that they were designed to place in a bookshelf and blend in with the books already there. They were made by a company called Stanford Advanced Acoustic Technology which was affiliated with Allison Acoustics. A very simple MTM design that was inexpensive and became invisible in the right setting. They sound better than not being able to have any speakers...

HoM speaker a.jpg
 

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DanielT

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Here is a CONCRETE cabinet monitor speaker from Sweden, the Rauna Tyr II. It has a 5.25" woofer for scale and a cast CONCRETE cabinet that is extremely heavy for a small monitor speaker. The slip-over grill socks are off for the picture.

In this picture they are powered by a 20 wpc pure Class A audio amplifier deck I built that runs hot enough that you actually cannot touch the side heat sinks until five minutes after you turn the separate power supply off. The separate linear power supply is designed for continuous duty at 600 Watts AC input delivering +/- 35 VDC. I built the supply as a test-bed for use with a multitude of Audio Amplifier Decks I was building with different topologies.

View attachment 159052
He was a really cool nice person, the designer Bo Hansson of those speakers,Rauna Tyr II.

We come from the same city in Sweden. Unfortunately, Bo died a few years ago. It would have been really cool to visit him. In the picture you can see the mouth of his horn. Horn mouth in the floor in the living room. The horn speaker itself he built in the basement.
unnamed.jpg


Picture with the white speakers, model Rauna Njord by Bo Hansson. I have had such. Built in concrete..they were ... stable..and good ..:)
images.jpeg
 
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