Yamaha NS-570 ear speakers identified and procured

[Speedbump71]

What is it besides a Yamaha? Cant find any pics for clues. The white around the grill has me wondering if they got painted.

 

[Gazdatronik]

I don't think Yamaha. Their logo has the name under the roundel, and has been pretty consistent in design.

 

[Speedbump71]

Well they have these...no pics of back of cabinet.

 

[Gazdatronik]

Huh cool I'v never seen an inverted logo. It would seem like these should be easier speakers to identify, very unique cabinets.

 

[Gazdatronik]

WAIT I rermember now....Part of the ear speakers thing they were doing. I thought that stripey cloth was familiar. NS-570 I bet.

 

[Speedbump71]

Yep that's it. Right down to the paint.

Thanks!

 

[gdmoore28]

Good call, Speedbump!

Those are some odd looking rascals, for sure.

GeeDeeEmm

From the interweb: Yamaha NS570

 

[roadrunnerx]

Now that is a woofer I'd hate to refoam!
Amazing looking speakers.

 

[Nat]

I yearn to hear these! You can take your racetrack KF B139s, I want the even more asymmetrical ear speakers.
Given that you live far far from me, and you haven't invited me over to listen to them, I have to rely on your reporting of your impressions.
Please post them.

 

[JimPA]

Those woofers look like a black sink.
If the dust caps and voice coils were removed that is where the drain pipe would be.

 

[Speedbump71]

I yearn to hear these! You can take your racetrack KF B139s, I want the even more asymmetrical ear speakers.
Given that you live far far from me, and you haven't invited me over to listen to them, I have to rely on your reporting of your impressions.
Please post them.

We shall see if I end up with them. I am being very careful what I use to take up space in the basement these days

 

[Nat]

Oops - by 'please post them' I meant please post your impressions of how they sound, not post them for sale. I realize that it would be easy to misconstrue what I meant, since I did so myself when I read the thread again today. Obviously, what you do with them is your business, not mine. Sorry.

 

[toxcrusadr]

What the heck is that?!

 

[Marine0811]

Those are definitely some strange looking woofers

 

[frommerstop]

They worked by the same principle as Bertagni (BES), or later Meliors & Sumos.
The “cone” is really a soundboard, sound is generated by the voice-coil/motor as it excites the board sending ripples across it’s surface. Think of a Walsh driver, but flattened.

 

[toxcrusadr]

I just always kind of assumed that one Yamaha NS was pretty much like another, but it's not so!

 

[Nat]

My impression is that the ear speaker is actually more like the KEF B139 - even if the front surface is flatter than the normal deep cone, it still is a more or less rigid piston, driven by a standard voice coil, and with a normal surround. And, if memory serves, the cone is some sort of damped styrofoam, like the B 139, which would be a bad design for a traveling wave kind of design.
I know Mark Hardy used to have one of them - perhaps he knows.

 

[Nat]

Well, my interest was piqued, and poked around a bit, and now I'm even more confused. There appear to be more guesses than actual answers about the nature of the design. The ear speakers I have seen had a sort of flattened cone, but apparently there are other versions that are flat, but with convoluted tapered ribs. To me, that suggests the intention of pistonic motion, but then there is a statement that the surrounds are stiff. I don't know if it's simply a matter of the surrounds having stiffened over time, or whether they were designed that way, but there being a surround at all implies (in my mind, at least) that the driver works by moving back and forth rather than having waves travelling through it - I do not believe the flat speakers the ear is compared to have real surrounds - the styrofoam ones I've seen have a sort of channel in the foam that (they hope) terminates the wave, rather than reflecting it, and the other ones have sufficiently flexible panels so that a surround isn't needed.
But this is all hypothesis, and I can't claim any certainty. I'd like the find the High Fidelity or Stereo Review review from the mid or late 60s that I remember reading back in the 70s.

 

[Speedbump71]

Bid placed. They were much larger when I inspected them than I expected. We shall see if it was meant to be

 

[Speedbump71]

Bid was more than enough, and I brought them home, along with another little set of Yamahas. Pics and impressions to follow.......