[ericj]

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Originally Posted by Faust2D /img/forum/go_quote.gif These frames look a lot like MB QP70

Yup, that sure looks like cardamatic suspension.

 

[Crowbar]

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Originally Posted by audiomagnate /img/forum/go_quote.gif I spent several hours with the Hill Plasmatronics back when they were new. Just the tweeter was plasma

Crossover was 1000 kHz, but someone modified it for 700 Hz.

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the more it sounded like you were listening to live music in the next room through a 1 inch hole in the wall. I think you might be on to something.

You bet! But my version is an improvement. Lower crossover, no helium. Tradeoff: expensive electrode materials, large power consumption and heat output, and potential need for venting ducts. Like I said, the perfect audiophile thing. Who knows, I might actually think of commercially doing this, but it will be at least a year from now, as I've got my attention on other things. The safety concerns are I think the biggest problem here. Having a signed release form doesn't mean it will necessarily stand up in court if someone knocks one over and catches the house on fire... I'd say 1 to 3 that I'll actually do it.

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Originally Posted by steaxauce /img/forum/go_quote.gif When can I preorder?

I'm still not sure glow discharge headphones are practical, specifically due to the need of an active cooling system. A simpler choice would be a clone of the Plasmasonics, which anyone can build in a day, including the HV amp--construction is obvious from the website mentioned previously. Of course, just because it's not practical doesn't mean I may not attempt it

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Originally Posted by naamanf /img/forum/go_quote.gif I have been in love with the Acapella speakers for some time. They are some of the finest sounding speakers I have ever heard. It is just the tweeters that are plasma. They run from about 5K up.

The Plasmatronics' glow discharge upper mid/tweeters which audiomagnate mentioned are far better than corona discharge tweeters. Hill's patented design shows what a physics researcher for the military is capable of. In my version, the crossover is 400 to 500 Hz, so one only needs to add woofers to that (maybe giant electrostatic panels to try to approach the quality of the plasma top...).

 

[Joshatdot]

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Originally Posted by Carl /img/forum/go_quote.gif Oh yes, they exist all right. Google for PlasmaSonic headphones. The things swung 3000 volts of corona discharge half an inch from your ears. I love it. Of course, with typical French build quality and a 15 odd years of time having past since they were made, I'm not sure even I would risk listening to a set, at least without some pretty serious refurbishment. The amp they came with sucks badly from what I understand, so part of any DIY project involving them would have to include making a proper amp for them.

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Originally Posted by Duggeh /img/forum/go_quote.gif Plasma headphones, complete with Hirschmann connector. Clearly the choice of the professional.

Duggeh...are you gona get these

 

[Duggeh]

Not if I could spend the money to buy a pair of TakeT H2s.

 

[Crowbar]

Duggeh, those are headphones that produce sound by moving significant mass--just like dynamic and electrostatic headphones. Mass has inertia, and that causes distortion. It's as simple as that. The plasma, on the other hand, if cold is the density of air, and if hot like in the Plasmatronics, even lighter. So what is by far the largest distortion mechanism is removed. There's basically no comparison between the plasma drivers and everything else (short of hooking up electrodes to your auditory nerves).

BTW, another note to the person that mentioned Acapella above: their plasma tweeters are horn loaded. Why ruin a good thing by adding what is essentially a distorting transmission line? Just because they didn't want to run more power to get a decent frequency response without the horns.

I may try to build clones of the headphones from the first post later this summer and I'll post build instructions here. Parts cost would be less than $50 for headphones and a basic amplifier.

 

[Duggeh]

Indeed Crowbar, I recognise the inherent advantages of the plasma driver, however I also recognise the difficulties in its proper implementation, in particular, low frequency reproduction is much more difficult, just like it is for panel piezo, magnetic AMTs or some electrostatic designs.

However you phrase your post as though there is an alternative, which at present there is not. The amalgamated design of the TakeT piezo AMT I have been listening to for several weeks now and it is stunning in every way.

Once you get your plasma headphone design up and running I would be delighted to try it out of course, but at the moment, stats, amts and piezos are the closest we have.

 

[Crowbar]

Quote:

Originally Posted by Duggeh /img/forum/go_quote.gif Ilow frequency reproduction is much more difficult

This is most definitely false in the case of headphones. Once again I post this graph; there's no falloff whatsoever in the low frequencies:

Plasma only falls off in low frequencies when there's insufficient power. For speakers that makes most plasma designs impractical to crossover below the mids, but for headphones it's a nonissue.

 

[Duggeh]

Flat response, if I read that graph correctly, can stil be percieved as fall off because of the extra volume needed for lower frequencies to percieve the same volume. Fletcher Munsen curves I think they are called.

Im not calling you technical expertise into question, you are clearly an expert here and im the idiot, but my main point is that until there is a viable plasma option availible on the market, the Stax, Ergo and TakeT are the next best options.

Reading about the plasma speaker mentioned, the crossover frequencies seem to correlate with the ones used in Precide's AMT speakers.

 

[ericj]

I think I'll build DIY plasma 'phones a while after i build DIY 'stats.

I'm not saying that jokingly, that's literally where I'm putting my priorities.

I also don't plan to build my own 'stat drivers until some time after i remodel my livingroom.

 

[Crowbar]

Quote:

Originally Posted by Duggeh /img/forum/go_quote.gif Flat response, if I read that graph correctly, can stil be percieved as fall off because of the extra volume needed for lower frequencies to percieve the same volume. Fletcher Munsen curves I think they are called.

You seem to be mixing things up here. Real life sounds are all changed that way by the ear. Correcting for the ear's nonflat response means you'll create unreal sounds.

Any real life sound will be subjected by the same FM curve weighting by the human ear. Therefore, for headphones to reproduce the sound of something from real life, they must have an exactly flat response.

It's pretty simple really if you think it through. Say you're at a live concert and someone is playing an instrument that is playing a note whose response at 30 Hz has intensity 10 dB, and the same at 3000 Hz. Your ear will result in the 30 Hz component being perceived as far quieter.

Now say you listen to a recording of this. Flat response headphones would reproduce the same effect as the live listening, which is obviously the goal here. Heapdhones with inverse FM response would make the 30 Hz and 3000 Hz components sound equally loud to the ear, which will sound extremely unrealistic. If you look at an actual FM graph, you'll see that your ear perceives 30 Hz as 65 dB quieter than an equivalent intensity 3000 Hz, an enormous amount.

 

[Duggeh]

Flat response is truth, but is truth beauty?

People like colouration, thats why there is such a huge difference in sound between studio monitors and most hi-fi speakers.

 

[Crowbar]

Are you saying that a live concert doesn't sound good? You must be listening to the wrong ones

The live experience: when I play the piano or the pipe organ, or listen to the orchestra, acoustical jazz music, or just someone's singing voice, I can tell you that coloration beyond the timbre of the instruments and vocal cords already present will only serve to obscure things, and is the last thing that should be added to adulterate the sound.

Regarding studio monitors, they have distortion issues like other speakers, among other things like phase alignment and dispersion. Response is just one thing to consider

An example of hifi speakers that minimize all of these problems and reach for transparency are the Nautilus Prestige speakers, and they have fantastic reviews (without which I doubt BW could charge the insane prices they do).

Plus, any euphonic distortion can be added by DSP or analog filters. However, you can't in general do the reverse, if a system is already distorting, to give it any other distortion profile you choose.

 

[Duggeh]

Haha, no I love live music, however comparing the flat response of live music to the flat response of recorded music is still apples and oranges, theres far too many other factors beyond frequency perception to deal with.

Those who aim for live sound reproduction in hi fi chase the impossible dream imho.

As for the Nautilus, at that price level, I'd sooner try some Quad electrostatics or a Heil loudspeaker.

 

[Crowbar]

It's far from an impossible dream. The most critical thing is recording and playback geometry. A few speakers in principle can't recreate a proper sound field at the ears. The optimal configuration is binaural recordings and the user's own head-related transfer function in DSP. You can get to a point where it's indistinguishable from live if the person closes their eyes. It's just at this time a good amount of effort, and lack of proper recordings is a barrier.

 

[Duggeh]

Binaural has the ability to sound utterly astonishingly immersing, i had always hoped that a binaural version of 5.1 tracks on DVDs would catch on but it never did, the only film I can think of that has one is Pearl Harbour and I'd sooner spoon out my eyes than watch that cinematic abortion again.

Accounting for HRTF is also an excellent idea and AKG did it for a time with the K1000.

I think ultimately what is needed is for a record label to specialse in binarual recordings and remixes. Get those 5.1 SACD and DVD-A masters of older albums put to binaural. As you say, without the proper recordings we are going to be stuck.