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Coaxial Ribbon Midrange/tweeter - Can a small midrange ribbon actually do midrange well?

Fellow Members: my apologies if you may have caught a similar discussion under Piega 511 Coax Loudspeakers. That title may not reflect the general interest I am hoping for.  

I am wondering, from a technical standpoint, how the Piega 511/711 Coax loudspeakers use a relatively small coaxial ribbon mid/ tweeter array driver to cover the entire midrange.  I always thought of smaller ribbons as excellent tweeters only.  If it does cover the entire midrange, can it move enough air to make
an impactful presentation for large orchestra or rock music, for example. Reviews praise the speaker’s agility, resolution and accuracy. It sounds like a most worthy competitor in its price range but I want a loudspeaker that can do most genres well.....not just vocals, chamber music and jazz.  Thank you in advance for your input. 
audiobrian
12 responses Add your response
shadorne's avatar
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shadorne
7,477 posts
 
I would be more concerned about ringing. The grill housing of the midrange tweeter system is all metal. This is going to want to vibrate big time.

The crossover is around 400Hz so the ribbons are going to have to work hard. Indeed your concern about maximum SPL is a valid one. Ribbons are not known for high SPL capability except when used in tweeters. The lower the operating range the greater the excursion required.

If you want a speaker that does everything well (rock and large orchestral) and covers the entire midrange with a single driver then look no further than ATC. 


bdp24's avatar
bdp24
9,788 posts
 
The Eminent Technology LFT-8b uses a pair of magnetic-planar drivers to cover 180Hz to 10kHz, crossover free within that frequency range. I ribbon tweeter takes over at 10k, and an 8" dynamic woofer at 180Hz. The 2014 Robert Greene review of the speaker in TAS is worth a read.
erik_squires
16,056 posts
 
Interesting. I'd say there's a lot to consider.

This is a rather large ribbon. The larger the surface area, the less it must move to achieve a given sound pressure.

I will say that the masurements from the C8 LTS are encouraging. The impulse and waterfall displays show an uncommonly good time domain pattern.
The off center isn't great, and hte impedance plot is VERY interesting.

I would not say it is impossible. I am using a pair of AMT's down to about 1.8kHz and the dynamic range and power handling is amazing.
erik_squires
16,056 posts
 
Should add, this is not the first time a planar midrange has been envisioned.  The most famous are the Infinity and Genesis towers.
bdp24's avatar
bdp24
9,788 posts
 
Erik, I assume you meant to say "ribbon" midrange. As you know, there are many planar midrange drivers---the other Eric (with the inferior spelling ;-) .
audiobrian OP
184 posts
 
I truly appreciate the responses so far. The Eminent Tech speakers have a much larger/longer midrange ribbon array than the Piega 511 Coax Loudspeakers. This is why I find it hard to believe this Piega coaxial driver can generate the necessary SPL for more demanding music and without distortion.
bill_k
912 posts
 
I owned their earlier model C10 Ltd. which also used a version of their hand made coaxial midrange/tweeter. While they refer to them as 'ribbons' they're actually planar magnetic in design, since the conductive foil elements are on a substrate rather than being freely suspended in their magnetic field. They have a very detailed and pure quality to their sound and image exceptionally well. I'd strongly suggest an audition before making such a purchase since individual preferences and system matching will play a large part in determining whether they're the right choice for you.
erik_squires
16,056 posts
 
Erik, I assume you meant to say "ribbon" midrange. As you know, there are many planar midrange drivers---the other Eric (with the inferior spelling ;-)
.
@bdp24

Not at all. I meant "planar" in the generic sense, including ribbon, planar magnetic or even ESLs, in that the radiating surface describes a plane instead of a cone. I’m not sure I’ve ever seen a true ribbon midrange though.


bdp24's avatar
bdp24
9,788 posts
 

@erik, are you forgetting about the Apogee Acoustics full range ribbon loudspeakers?

But let me back up. I asked if you meant to say "ribbon" in your sentence "this is not the first time a planar midrange has been envisioned". I did so because the "this" in the sentence I took to be referring to the speaker the OP is asking about, a loudspeaker with specifically a ribbon midrange, not a generic planar one.

In regards to planar midrange drivers, of course the Piega 511 is not the first speaker to employ them! My God, that goes back to the 1950's. QUAD, KLH, and Dayton-Wright ESL's, Magneplanars in the early-70's, the Infinity IRS and RS-1b, all the ESL's introduced in the 1980's and later, the ET LFT's, and many more.

So Erik, what do you mean by "a planar midrange"? 

erik_squires
16,056 posts
 
How many times must I answer the same question?

Not at all. I meant "planar" in the generic sense, including ribbon, planar magnetic or even ESLs, in that the radiating surface describes a plane instead of a cone.

So, that was what I meant originally, when I used the term "planar" as in "describes a plane" and when I wrote this:

I did so because the "this" in the sentence I took to be referring to the speaker the OP is asking about, a loudspeaker with specifically a ribbon midrange, not a generic planar one.


Except the speaker the OP is referring to does not appear to be a true ribbon.


I’m not sure I’ve ever seen a true ribbon midrange though.

I was thinking about a true ribbon midrange, characterized by extremely low impedance, and a conductor alone forming the moving element.  Often transformer coupled.

Yes, I completely forgot about the Apogee Acoustics models.



Best,
E
audiobrian OP
184 posts
 
Yes, I watched a factory tour video on YouTube explaining ribbon production and cabinet construction at Piega.  The video and emails with Piega indicate the 511/711 coaxial ribbons are actually excellent planar magnetic drivers, aluminum elements printed on a stretched plastic membrane. I plan to audition early 2019. Thanks again. 

audiobrian OP
184 posts
 
Just wanted to give feedback on my audition of Piega 711s.  They are remarkably resolving and transparent, possibly the best I’ve heard; wide sweet spot as well, characteristic of coaxial drivers. However, I felt the speakers were a bit “thin sounding” in the midrange and lower treble. I listen to a good amount of pop and rock & roll music.  When listening to Queen, Freddie’s voice lacked the “meat on the bone” I’m accustomed to.  That said, the Piegas sounded incredibly good with smooth jazz. All drivers and speakers have their own signature and strengths, very true of the Piega coaxial ribbon/planar magnetic.
I think I’d prefer losing a wee bit of resolution in exchange for a more organic/natural presentation..... however I can understand why some would take out their credit cards on the spot and why these loudspeakers were so highly praised in The Absolute Sound!  Thanks again to all respondents.

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