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Tuckerfan
2008-Nov-06, 10:26 PM
They're apparently real, and judging from this Instructable (http://www.instructables.com/id/Build_A_Plasma_Speaker/), look wicked. I can't imagine that it'd be good for any electronic gear to be close to them, and you'd probably want to put some kind of enclosure around them to keep small children and animals from trying to touch the streams. Still, I keep staring at the corners in my living room and thinking that it'd just be awesome to have giant plasma speakers in them. (Not that I could afford the electric bill for that, I'm sure.)

http://www.instructables.com/files/deriv/F4Z/1L83/FMMCVKR2/F4Z1L83FMMCVKR2.MEDIUM.jpg

Siguy
2008-Nov-06, 10:48 PM
Amazing! Both an audio device, and an arc welder! :P

Sounds kind of squeaky. Maybe immersing it in a heavy inert gas like Argon or Xenon would help? I suppose a big one would sound pretty good, but that would be horribly dangerous and kill your electric bill. In addition, I would think graphite would work better than nails for an electrode.

I wonder if you can make them with low amperages. Then they would be a lot cooler. I like high voltage electricity, just not the dangerous part. Seriously, if it didn't have to deal with thousands of amperes, I would build my own magnetoplasmadynamic thruster.

Nicolas
2008-Nov-06, 10:52 PM
If you want rather "safe" high voltage circuitry, build electrostatic speakers. I think, but I may be wrong, that magnetostatic has way lower voltage, but that in itself says nothing about sound quality. In any case, both are a nice alternative for conus speakers, from an engineering point of view.

cjl
2008-Nov-06, 11:24 PM
They are, though I've yet to hear any with quite the impact of a good cone based setup. Great clarity though.

Oh, and I need to try making one of those plasma speakers. Looks awesome :D

Nicolas
2008-Nov-06, 11:37 PM
That notorious friend of mine played with 6 [six] Magnepan speakers. 2 for mids and highs, and 4 for bass, actively bi-amped. With that kind of foil surface for bass reproduction you get a really serious bass, but then still it struggles to get the punch of cones. Things like Carvers are a good alternative: serious cone action for the punch in the lows, sweet foil for the mids and highs. Quite some speakers use this combination.

HenrikOlsen
2008-Nov-07, 12:53 AM
Good instructions here (http://www.plasmatweeter.de/eng_plasma.htm) and here (http://www.ece.villanova.edu/~cdanjo/plasma.html) for a plasma flame tweeter, rather than an arc speaker.

Main problem is that the frequency response doesn't really go flat until around 5kHZ, so you'll need decent midrange speakers as well, but then it's flat all the way up to bat range.

jj_0001
2008-Nov-07, 06:23 PM
The real problems are several:

1) The cutoff frequency (low end cutoff) is about when the arc length matches a wavelength. So you need a LONG arc to do much of anything useful.

2) They make tons of ozone, and can make you sick.

Other than that, Ms. Lincoln.

sabianq
2008-Nov-07, 06:52 PM
Plasma speakers are actually Plasma "tweeters".
and i would guess that as JJ 0001 suggests, they lack low frequency reproduction ability, but not because of the length of arc needed, rather the arc begins to flap about so much at the lower end that the noise of the flapping would most likely override the signal level)

(even the tiniest little speakers can reproduce frequencies lower than 20 Hz, it is more of an amplitude restriction)

I have auditioned them and have helped a friend of mine build a working prototype.
I would suggest that the plasma tweeter is the is perhaps the best high frequency driver in existence, the fact that there are no moving parts keep mechanical distortion to non-existence levels.

by keeping the arc to a low level, the signal to noise ratio is amazing.

and the frequency response of the system is theoretically absolutely flat, depending on the modulation source.

as for Ozone production, it is minimal as an Ionic Breeze produces more ozone if the "speaker" is set up right

sabianq
2008-Nov-07, 07:01 PM
check this out if anyone is further interested.


http://web.mit.edu/dzshen/www/home_files/PlasmaTweeter-FinalPaperV1_3.pdf

mugaliens
2008-Nov-07, 09:57 PM
First made in 1900 by William Duddell (http://120years.net/machines/arc/). He called it his "singing arc."

An individual arc is only useful for very high frequencies, as each arc only moves a small volume of air. However, plasma speakers consisting of hundreds of such arcs in a planar array reproduces mids fairly well. For bass, though, nothing beats a a large diaphragm.

jj_0001
2008-Nov-07, 10:29 PM
To clarify, it's not only the maximum level that falls off with decreasing frequency, it's also the amplitude response.

As far as ozone, it's bad for you from any kind of device.

sabianq
2008-Nov-08, 12:49 AM
First made in 1900 by William Duddell (http://120years.net/machines/arc/). He called it his "singing arc."

An individual arc is only useful for very high frequencies, as each arc only moves a small volume of air. However, plasma speakers consisting of hundreds of such arcs in a planar array reproduces mids fairly well. For bass, though, nothing beats a a large diaphragm.

very true about the large diaphragm,
but it has been discussed here how even the tiny ear buds can reproduce frequencies below 20Hz.

however, if you want serious bass, with high energy compression and rarefaction down below 1Hz, with check this out...

The ROTOSUB...

a rotating, servo activated subwoofer.
using a concept not unlike a turbo fan, the Rotosub used servo controlled fan blades to compress and rarefy the air in a space, the fan is spinning all the time and the blades change pitch to produce the pressure wave.
http://www.rotosub.com/
http://www.soundimage.dk/images/trwanimate.gif


I have had the pleasure of feeling one of these,
a high resolution recording of a helicopter idling then taking off makes you actually feel like you are standing in front of a real honest to god helicopter.

nothing like it in the world of acoustics.

Nicolas
2008-Nov-08, 10:24 AM
The modified "flat until below 20Hz" Tannoy Ardens will arrive here in about 2 hours. That should be good for some serious 15" earthquakes.

I'm curious whether they will be able to release their full quality potential (not volume...) in my small living room though...

cjl
2008-Nov-08, 11:07 PM
That should definitely be interesting. Sub-20Hz sound is really odd feeling when it is really loud.

mugaliens
2008-Nov-09, 12:00 AM
The ROTOSUB...

a rotating, servo activated subwoofer.
using a concept not unlike a turbo fan, the Rotosub used servo controlled fan blades to compress and rarefy the air in a space, the fan is spinning all the time and the blades change pitch to produce the pressure wave.
http://www.rotosub.com/.

:doh:

Why didn't I think of that?? ! Seriously, that's a pretty cool concept. I do wonder, though, how they remove the fan noise.

sabianq
2008-Nov-09, 01:15 AM
the fan is isolated in another chamber. like a folded horn...

15000 bucks?
easy to build?
maybe...
hmmm.....

Nicolas
2008-Nov-09, 09:58 AM
I've got the Ardens here now. Still need to finetune the setup; they're standing a bit too low, a bit too much in a corner behind a couch, not symmetrical enough...will be alright later today :).

In my small living room they don't release their full potential in the lows (they used to stand in a 100m▓ living room, THAT was awesome), but they sound amazing. The best thing is that you get a full-range sound already at low listening levels, and the sound can be very peaceful. Loooovely late in the evening. And if you want loud, they deliver too. But for really loud, you'd need a really large room.

I also still need to "fill" the room a bit, it's a hard empty room at the moment.

Oh, and I still somehow have to pay them. I suddenly feel a bit sick, how strange... ;)

mugaliens
2008-Nov-09, 11:50 AM
Oh, and I still somehow have to pay them. I suddenly feel a bit sick, how strange... ;)

At least now you can tell yourself it's just the LFEs, and not because you spent more on speakers than you needed to...:lol:

Do they at least have modern materials which aren't prone to disintegration over time? I had a pair of Bose spekers who's rubber surround disintegrated.

Twice.

After it happened the second time, I switched to BA, and haven't a problem with that, since.

Nicolas
2008-Nov-09, 12:09 PM
Lots of speakers use surrounds that disintegrate over time. Unless really old types, rubber surrounds don't have this problem. Foam does (and I believe Bose used foam). The choice of material mainly depends on how compliant they want the surround to be.

Mine use Tanoplast. Original Tanoplast used to disintegrate after 15 years. Modern Tanoplast can last 25-30 years easily, and mine is only 4 years old.

So by the time that's disintegrated, I hope to have saved enough :).

mugaliens
2008-Nov-09, 11:11 PM
Tannoy. Tannoplast.

You know, while I applaud your afficianado for music, I'm beginning to tire of Tanneverything, tanknow?

There are many other find speakers out there.

ktesibios
2008-Nov-10, 03:21 AM
Plasma tweeters were marketed in the '50s and '60s by DuKane, Fane, Electro-Voice and Plessey. Here's (http://www.ionovac.com/dshistory1.htm) a page about the history of the "Ionovac".

These designs coupled the arc to a horn to improve efficiency by providing a better acoustic impedance match between the arc and the air. They're said to have sounded very good, but the ozone production and the rather short life of the electrode and arc chamber were nuisances. Replacement parts for Ionovac tweeters can still be had, and there are apparently some audiophiles who still use them.

Incidentally, a company called Servodrive manufactured subwoofers which used a rotary motor and belt arrangement to drive a cone which was coupled to a horn. This allowed them to obtain much higher cone excursion with better linearity than conventional voice coil motor structures (for subwoofers volume current- the volume of air the driver can displace, which is proportional to the product of projected cone area and maximum displacement- is the name of the game if you want loud bass).

I encountered some of these at a trade show back in the late '80s. When they fed a 15Hz tone into a set of them, the whole **** room seemed to pulsate as did the guts of anyone in the room.

Nicolas
2008-Nov-10, 07:54 AM
Tannoy. Tannoplast.

You know, while I applaud your afficianado for music, I'm beginning to tire of Tanneverything, tanknow?

There are many other find speakers out there.

Of course there are, but I can't lie, can I? You told about speaker surrounds, mine have Tanoplast surrounds. Honestly ;). And there are only so many materials to use for surrounds: foam, natural rubber (hardly ever used), synthetic rubber, reinforced vulcanized fabrics (mainly in the PA world), and then some special materials such as tanoplast. Tanoplast and foam, and some old types of rubber, are the types that disintegrate over time, so that's why I mentioned Tanoplast. Modern rubbers and vulcanized fabrics don't. The main reason why synthetic rubber is used most for home speakers these days.

But I know that there are many other fine speakers out there. I'll tell you more, I nearly bought myself a pair of magneplanars yesterday. They were priced really well... And of course, magneplanars are slightly more on topic here than surround materials of fetish brands. ;) :D

cjl
2008-Nov-10, 08:24 AM
There are many fine brands out there :)

I'm partial to B&W myself :)

Nicolas
2008-Nov-10, 08:29 AM
I've heard really nice B&W's on really nice vintage Sansui gear, and I wasn't impressed by the result. But my guess is the problem was with the Sansuis...

For a nice "dark pub" sound, I like these huge old JBL's. And things like magnepans for a laid back sound.

There's so much choice, so many good speakers...

sabianq
2008-Nov-10, 01:53 PM
here is my personal portable system,
I use this for parties and public address venues where there is less than 700 or so people.

2 MRX512M by JBL
http://www.jblpro.com/catalog/general/Product.aspx?PId=50&MId=3
Power Rating : 400 W / 800 W / 1600 W
Frequency Range : 60 Hz - 20k Hz
Dimensions
(H x W x D) : 645 mm x 380 mm x 345 mm
(25.25 in x 15.0 in x 13.5 in)
Sensitivity : 97dB SPL
Frequency Response : 90 Hz - 20k Hz
Nominal Impedance : 8 ohms
Rated Maximum SPL : 129 dB SPL continuous
Coverage Pattern : 70║ x 70║ nominal
Weight : 14.9 kg (33.0 lbs.) (so much lighter than my old Mackie S408's)
High Frequency Driver : 1 x JBL 2408H 37.5 mm (1.5 in) annular polymer diaphragm, neodymium compression driver
Low Frequency Driver : 1 x JBL 262H 305 mm (12 in) Differential Drive« woofer
(neodymium motor)

http://www2.jblpro.com/BackOffice/ProductPictures/3c30d5cf-8b76-477b-aaf2-40182233d303.jpg

The Amplifier I am driving them with is a High efficiency, Class H (3 tier) Power amp
http://www.qscaudio.com/products/amps/powerlight/powerlight.htm
PL4.0
Stereo Mode (both channels driven) Continuous average output power per channel
Ch 1 and Ch 2
8Ω / FTC 20 Hz - 20 kHz / 0.1% THD 900 W
8Ω / EIA 1 kHz / 0.1% THD 1000 W
4Ω / FTC 20 Hz - 20 kHz / 0.1% THD 1400 W
4Ω / EIA 1 kHz / 0.1% THD 1600 W
2Ω / EIA 1 kHz / 1% THD 2000 W

Bridge Mono Mode
8Ω / FTC 20 Hz - 20 kHz / 0.1% THD 2800 W
4Ω / EIA 1 kHz / 1% THD 4000 W

Distortion (SMPTE-IM) 0.05%
THD (typical) 4Ω to 8Ω 20 Hz - 20 kHz, 10 dB 0.01%
below rated power. 1.0 kHz and below. full rated power

Damping Factor (1 kHz and below) > 500
Signal to Noise (20 Hz - 20 kHz) 105 dB

Voltage Gain 80x (38 dB)
Output Circuitry Class H (3-tier)
Cooling (Variable speed fans, rear-to-front air flow) Single fan Single fan Single fan Four fans
Weight (net) 30 lbs
120 V Current Consumption 15.2 A
(1/8 Power Pink Noise at 4Ω)
Multiply current by 0.5 for 230 V units

Connectors (each channel)
Input: Neutrik “Combo” XLR + 1/4" / TRS input and barrier strip
Output: “Touch proof” binding posts
Frequency Response
20 Hz – 20 kHz / ▒0.15 dB
2 Hz - 50 kHz / +0, -3 dB

http://www.qscaudio.com/images/products/powerlight/pl60_front.jpg

I use a Mackie 1202 VLZ3 as a mixer/preamp
http://www.mackie.com/products/1202vlz3/
http://www.sweetwater.com/images/items/215/1202VLZ3.jpg

A sure Wireless Handheld microphone
ULX series
http://www.shure.com/ProAudio/Products/WirelessMicrophones/us_pro_ULXP_content
with a hypercardioid neodymium capsule.

In my Processor rack I have a:
Sabine 1200 RTA/workstation,
Lexicon MX200 processor
Dual Klark Teknik DN405 Parametric Eq's
Dual DBX 160 Compressors/limiters

I love the system, Very light, extraordinarily quiet at full output with no signal, an amazing headroom capable of 123 dB SPL continuous (129 dB SPL peak), and a super flat frequency response (on axis) of +-3 db from 100Hz-20KHz

cjl
2008-Nov-10, 06:58 PM
I've heard really nice B&W's on really nice vintage Sansui gear, and I wasn't impressed by the result. But my guess is the problem was with the Sansuis...

For a nice "dark pub" sound, I like these huge old JBL's. And things like magnepans for a laid back sound.

There's so much choice, so many good speakers...
Which ones?

I haven't heard the older ones, but the new B&Ws sound almost universally fantastic IMO, with the exception of the 600 series floorstanders (which are muddy) and the 705s (which lack guts).

Nicolas
2008-Nov-10, 08:23 PM
Recent ones. 704 or something similar. But anyway, if they're hooked up to muddy sounding equipment, even the best speaker will sound muddy. I think the problem in this case was with the equipment, not the speakers. I think the Sansuis could use a recap job after 30 years...

mugaliens
2008-Nov-10, 09:39 PM
Cool, sabienQ. I've installed/worked Mackie boards, before, along with QSC. The thing I like most about Mackie is their philosophy.

cjl
2008-Nov-10, 11:41 PM
Recent ones. 704 or something similar. But anyway, if they're hooked up to muddy sounding equipment, even the best speaker will sound muddy. I think the problem in this case was with the equipment, not the speakers. I think the Sansuis could use a recap job after 30 years...
That's probably it then - I have heard the 704's and absolutely love them - I'd own a pair if I could afford it. They have more clarity than the 600 series floorstanders, and they have much better bass than the 705's. They don't go tremendously deep, but they are clear to the depth that they do extend (around 40Hz).