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Backwards directed , rear-firing tweeter, Snell Type E / III?

DanielT

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Anyone have experience with such speakers? What are the advantages and disadvantages?

Grateful for response.

Snell Type E / III, just to show an example of what I mean:
5792811-7659-5__45467.1511219582.jpg

5792811-7659-9__29511.1511219582.jpg
 

solderdude

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Is the rear 'volume control' for the rear tweeter only ?
 

bigjacko

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I think the back tweeter is trying to make dipole response, but the woofer is not dipole, so don't know what is going on. Maybe try to make power response don't tilt as much in room and add some tweeter reflection?
 
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DanielT

DanielT

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Here is the information about the speaker. More than that I do not know:

shot_2021-12-29_09-56-54.png




Edit:

Hm, it was by pure chance I took the Snell as an example but it actually looks really exciting.:)

The Snell E/IIIs made a definite impression right away, and a good one. Despite their size, the E/IIIs came alive in my listening room, with a big soundstage presentation, a slightly forward quality, and no harshness or roughness. The speaker conveyed the warmth inherently present in music, while being open, fast, and showing considerable deep-bass extension.
 
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DanielT

DanielT

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I'm guessing it's a Vifa speaker element in that Snell E/IIIs

Peter Snell seemed to be a clever person, here to reduce floor reflexes (I suspect) Snell 1:

snell-acoustics-type1-1030526 (1).jpg
 

DSJR

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I had a pair of E-II's and they lasted precisely a fortnight (actually a weekend, the rest was treying to shift them on)! Ghastly crossover region 'edge' to the sound unless heard in a mid to far field and driven by Audio Innovation amps which masked it. They boomed too set on the floor and needed low 'Pirate' stands - all part of a UK mini cult in the mid 80's I remember. I look at the current Audio Note expensive knock-offs of these old models and wince with the memory as well as the price tags...

To the thread subject, I felt the rear tweeter did nothing really. Maybe it should have been put on top perhaps to add some image reducing 'air'?
 
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DanielT

DanielT

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I had a pair of E-II's and they lasted precisely a fortnight (actually a weekend, the rest was treying to shift them on)! Ghastly crossover region 'edge' to the sound unless heard in a mid to far field and driven by Audio Innovation amps which masked it. They boomed too set on the floor and needed low 'Pirate' stands - all part of a UK mini cult in the mid 80's I remember. I look at the current Audio Note expensive knock-offs of these old models and wince with the memory as well as the price tags...

To the thread subject, I felt the rear tweeter did nothing really. Maybe it should have been put on top perhaps to add some image reducing 'air'?
Aha, but then you have at least tested a couple of Snell.:)

Although I'm most interested in the principle itself.Let's say two good speakers, basically quite similar but where one has rear-firing tweeter.Will it get better off axes then? "Airier" or where the advantage lies (if there is any advantage).

A bit dipole response as bigjacko mentioned. They can be a little difficult to place? Distance from rear wall that is.

 
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DanielT

DanielT

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My guess is that speakers with rear-firing tweeter are best suited if there are several in the listening sofa. But if you sit alone in the "king seat", sweetspot and listen, it is not an advantage, maybe even a disadvantage.

Do you think that may be true?
 

Jim Taylor

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My guess is that speakers with rear-firing tweeter are best suited if there are several in the listening sofa. But if you sit alone in the "king seat", sweetspot and listen, it is not an advantage, maybe even a disadvantage.

Do you think that may be true?

Man, you're taking me back in time! I and several of my friends experimented with rear "ambient" tweeters (and mids) in the 80's. I never liked them out of phase (dipole) but sometimes liked them in-phase (omni). And when I say "sometimes", I mean rather rarely.

Other people felt differently. But everyone agreed on one point: the design could be optimized for a certain listening position. If used for a location where the listener moved around in a residential room, the effect was annoyingly inconsistent.

You need to take my opinion in context: I've always liked a more directional soundfield. I dislike omnis, bipoles and dipoles. So when I say that other people felt differently, I mean that some definitely thought that the effect was nice. Looking back, I'd say that roughly half the listeners felt this way. Jim
 

FrantzM

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Weren't the Snells designed by Kevin Voecs, now with Harman?
I did like the Snell Type B.. back in the days ...
 
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DanielT

DanielT

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Man, you're taking me back in time! I and several of my friends experimented with rear "ambient" tweeters (and mids) in the 80's. I never liked them out of phase (dipole) but sometimes liked them in-phase (omni). And when I say "sometimes", I mean rather rarely.

Other people felt differently. But everyone agreed on one point: the design could be optimized for a certain listening position. If used for a location where the listener moved around in a residential room, the effect was annoyingly inconsistent.

You need to take my opinion in context: I've always liked a more directional soundfield. I dislike omnis, bipoles and dipoles. So when I say that other people felt differently, I mean that some definitely thought that the effect was nice. Looking back, I'd say that roughly half the listeners felt this way. Jim

Execellt written Jim. Your post would very well also fit in this thread because there is a lot of talk in it that speakers should be listened to and not just study its data / measurements:



Weren't the Snells designed by Kevin Voecs, now with Harman?
I did like the Snell Type B.. back in the days ...

I do not know the story. Would be interesting to know more. I like Hifi History. This is on Wikipedia.

Snell Acoustics was an American manufacturer of high-end loudspeakers which was founded by Peter Snell (1946-1984) [1] in Massachusetts in 1976. [2] It ceased manufacturing in May 2010. [2]


However, I can offer this piece of Hifi history. About Yamaha:

Yamaha did not manufacture, develop or sell hi-fi at that time. Sonab entered into an agreement with Yamaha to build a development department and manufacture of hifi in Japan. Clas-Göran Wanning was the person who designed the electronics in Sonab. He was stationed in Japan and jointly built Yamaha as a manufacturing company of hifi for Sonab. So, Sonab,were the first hi-fi products that Yamaha manufactured. Lars Lallerstedt was responsible for industrial design. When Sonab withdrew from hi-fi, Yamaha had to take over laboratories and development department and Yamaha began to develop, manufacture, market and sell hi-fi products under its own brand.

Sincerely

Peter


Sonab:

"Stig Carlsson began designing speakers in the 1950s. In 1966 he founded the company Sonab. In the late 1960s, Sonab ended up in an acute economic crisis and was taken over in 1969 by state-owned companies. State-owned companies gave Stig Carlsson substantial research resources and after a couple of years, the 1970s series could be presented. In 1978, Statsföretag shut down Sonab and all speaker production, this after losing one hundred million kronor by trying to manufacture and sell poorly developed mobile phones without a market. [Source needed]




Stig Carlsson knew Peter Snell by the way, thus that circle was closed.:)
 
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Jim Taylor

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Your post would very well also fit in this thread because there is a lot of talk in it that speakers should be listened to and not just study its data / measurements:

I did not have sophisticated measuring instruments in those days. I was young and impecunious. But looking back, I believe that every single one of the characteristic that I heard then would now be easily measured and the cause identified. That would include comb filtering from reflections. I may be wrong on that, but I seriously doubt it. The measurements we see on this website are different from fullfield radiation measurements that take the complete environment into account. I have a great deal of respect for professionals who perform those measurements. My brain hurts just thinking about it. :) Jim
 
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DanielT

DanielT

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I did not have sophisticated measuring instruments in those days. I was young and impecunious. But looking back, I believe that every single one of the characteristic that I heard then would now be easily measured and the cause identified. That would include comb filtering from reflections. I may be wrong on that, but I seriously doubt it. The measurements we see on this website are different from fullfield radiation measurements that take the complete environment into account. I have a great deal of respect for professionals who perform those measurements. My brain hurts just thinking about it. :) Jim
I did not think of that. By the way, praise to Amir and everyone who performs with various measurements and tests.:)

Then you should interpret the results. This was an eye opener for me. This for example I did not know:

 

Jim Taylor

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I did not think of that. By the way, praise to Amir and everyone who performs with various measurements and tests.:)

Then you should interpret the results. This was an eye opener for me. This for example I did not know:


Excellent video and excellent explanation.
 
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Kal Rubinson

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Weren't the Snells designed by Kevin Voecs, now with Harman?
I did like the Snell Type B.. back in the days ...
I cannot comment on the Snells but Kevin Voecks, formerly of Harman/Revel, was on the team that developed the Ultima line. The first Ultima Studio and Ultima Salon sported rear-mounted tweeters which, iirc, were intended to improve the speaker's dispersion in the MF-HF crossover range. No such element was included in the successor Studio2 or Salon2 but the cabinet designs were drastically different.
 
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DanielT

DanielT

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Development of Stig Carlsson speakers. How they went from more or less omnis to have a more directional soundfield.

Picture 1: Sonab OA-5 Type 2, from 1973

Picture 2: Sonab OA-12, from 1978

Picture 3: Carlsson OA-50, from 1984

Picture 4, Carlsson OA-52.2, from 1996

John Larsen one of Stig's disciples. Here is his new one. You can see where he got his inspiration from.

larsen-9.jpg


 

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More Dynamics Please

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Don't remember the model number but back in the 1970s I bought a pair of big Rogersound Labs bookshelf speakers with rear-firing tweeters from the original RSL factory store in Canoga Park. My recollection is that the rear-firing tweeters didn't really add anything special to the overall performance but were a great talking point with my audio enthusiast friends of that era.
 

Duke

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Anyone have experience with such speakers? What are the advantages and disadvantages?

I've been manufacturing speakers with rear-firing tweeters for about fourteen years, but mine don't look like the Snell. Mine use horns.

One thing a designer can do with a rear-firing tweeter is, make the power response (the summed off-axis energy) smoother. For instance, the Snell's front-firing tweeter will have a pattern which narrows as frequency increases, resulting in a spectral imbalance between the direct sound and the reflection field. A rear-firing tweeter's response can be tailored to compensate for this.

A rear-firing tweeter's contribution will decrease the direct-to-reflected energy ratio, which may or may not be desirable depending on the specifics.

Depending on the reflection path lengths, a rear-firing tweeter will often shift the temporal "center of gravity" of the reflections back in time a little bit, which can affect the spatial qualities.

A rear-firing tweeter tends to increase the sense of spaciousness, but if it is too loud, it will degrade clarity and image precision.

And a rear-firing tweeter (with its associated high-pass filter) redistributes driver cost. So for equal driver cost, less money can be put into the front-firing drivers.

Obviously I think a rear-firing tweeter can be a worthwhile net improvement since I've been doing it for a long time, and obviously I'm in the minority.
 
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DanielT

DanielT

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I've been manufacturing speakers with rear-firing tweeters for about fourteen years, but mine don't look like the Snell. Mine use horns.

One thing a designer can do with a rear-firing tweeter is, make the power response (the summed off-axis energy) smoother. For instance, the Snell's front-firing tweeter will have a pattern which narrows as frequency increases, resulting in a spectral imbalance between the direct sound and the reflection field. A rear-firing tweeter's response can be tailored to compensate for this.

A rear-firing tweeter's contribution will decrease the direct-to-reflected energy ratio, which may or may not be desirable depending on the specifics.

Depending on the reflection path lengths, a rear-firing tweeter will often shift the temporal "center of gravity" of the reflections back in time a little bit, which can affect the spatial qualities.

A rear-firing tweeter tends to increase the sense of spaciousness, but if it is too loud, it will degrade clarity and image precision.

And a rear-firing tweeter (with its associated high-pass filter) redistributes driver cost. So for equal driver cost, less money can be put into the front-firing drivers.

Obviously I think a rear-firing tweeter can be a worthwhile net improvement since I've been doing it for a long time, and obviously I'm in the minority.
Thanks Duke, that was interesting! Fun with a different view of it.With your speakers, it is a fixed setting with a passive crossover filter or you have the option to regulate it, similar like Snell Type E / III? Do you have a picture of your speakers? It would be exciting to see.:)

Hifi seemed to be so much more wild in the past. It has probably gotten better in most cases, I can imagine. But that wacky madness doesn't seem to exist that much these days.

Although I may be wrong, here for example:

venus.jpg




Or with insect eyes:

double_impact_double_front-1.jpg


 
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