Ribbons

[JerryLove]

I was reading one of the neat quasi-technical documents infinity put out for one of it's older speakers. In the doc (need to re-find) they discuss at length why they were using EMIT and EMIM ribbons, and the importance of the cabinet shape they were using (curved trapezoid).

From what I can see: Infinity has essentially abandoned ribbons and that cabinet shape for conventional rectangles and dome tweeters (and cone mids).

So my question, in addition to "why did Infinity change course" (if anyone knows), is "what are the major disadvantages of ribbon tweeters?". Why (other than price) do the majority of builders choose domes instead?

 

[randyb]

I was reading one of the neat quasi-technical documents infinity put out for one of it's older speakers. In the doc (need to re-find) they discuss at length why they were using EMIT and EMIM ribbons, and the importance of the cabinet shape they were using (curved trapezoid).

From what I can see: Infinity has essentially abandoned ribbons and that cabinet shape for conventional rectangles and dome tweeters (and cone mids).

So my question, in addition to "why did Infinity change course" (if anyone knows), is "what are the major disadvantages of ribbon tweeters?". Why (other than price) do the majority of builders choose domes instead?

I will take a stab at some of the reasons real or imagined-

Distortion-higher distortion but some argue that the type of distortion generated is not audible. Dennis Murphy for one, does not believe that distortion on good ribbons is audible. I think TLS here on Audioholics does (he is not a fan of ribbons)
Expensive-generally good ribbons are expensive (oh you said other than price)
More fragile
Not very good vertical dispersion
Crossover may be harder to get right

 

[jinjuku]

Link to John 'Zaph' Krutke ribbon measurements. It's a quick read and informational.

 

[randyb]

link to Dr. Earl Geddes papers on audibility of certain types of distortion.

http://gedlee.com/distortion_perception.htm

FWIW, I would really love to have someone like Sean Olive and the Harman lab do some preference testing for the various types of tweeters-compression, dome, ribbon, etc. in well implemented designs. My guess, (and it is an unprofessional guess) is that any of them in well implemented designs would be equally desired assuming they are tested within their limits.

 

[JerryLove]

Link to John 'Zaph' Krutke ribbon measurements. It's a quick read and informational.

Then the reverse question: If ribbons are clearly inferior then, firstly: how come no one no one noticed for so long (infinity was obsessed with them when infinity was at the top of the heap) and why have they survived at all when less expensive and clearly better performing options are available?

What's the trade off? Ribbons are better at X while domes are better at Y? What are X and Y?

 

[randyb]

Then the reverse question: If ribbons are clearly inferior then, firstly: how come no one no one noticed for so long (infinity was obsessed with them when infinity was at the top of the heap) and why have they survived at all when less expensive and clearly better performing options are available?

What's the trade off? Ribbons are better at X while domes are better at Y? What are X and Y?

Pulled this off of ribbon manufacturer, but other than the distorion item, I think these are some of the reasons given. By the way, the recent S&V review of the Golden Ear speaker gave it a rave review with measurements to match--it has a ribbon tweeter.

1. lower mass, hence higher efficiency/frequency and better transient response.

2. better heat dissipation, hence better reliability and less thermal compression.

3. lower inductance, hence flatter impedance and frequency response.

Also from wikipedia
They are attractive in these applications since nearly all ribbon tweeters inherently exhibit useful directional properties, with very wide horizontal dispersion (coverage) and very tight vertical dispersion


4. homogeneous diaphragm movement, hence low distortion.


Maybe Sean Olive will happen by to post his thoughts on ribbons and Infinity.

 

[JerryLove]

1. lower mass, hence higher efficiency/frequency and better transient response.

2. better heat dissipation, hence better reliability and less thermal compression.

3. lower inductance, hence flatter impedance and frequency response.

4. homogeneous diaphragm movement, hence low distortion.

1. I'd like to know more about how this equates to sound.

2. Based on comments about repairs: ribbons seem less reliable.

3. I've not heard that tweets are generally the impedance problem in a speaker. Flatter FR would definitely be good, but can we support that given the distortion issue?

4. Which is exactly what ribbons are stated to be horrible at in the previously cited link. So are they high distortion or low distortion?

 

[Hocky]

I will bet a major part of it is because they're unconventional and unconventional in the eyes (or ears) of the typical consumer is bad. They're not accustomed to the look or sound and therefore immediately move onto something else. If stuff doesn't sell, it is not worth building.

 

[randyb]

1. I'd like to know more about how this equates to sound.

2. Based on comments about repairs: ribbons seem less reliable.

3. I've not heard that tweets are generally the impedance problem in a speaker. Flatter FR would definitely be good, but can we support that given the distortion issue?

4. Which is exactly what ribbons are stated to be horrible at in the previously cited link. So are they high distortion or low distortion?

well, have you read Earl's papers on distortion and what is and is not audible. I personally do not believe Zaphs distortion perspective and I know that him and Earl have gotten into it. By the way, Earl doesn't like ribbons but not because of distortion, but because of compression problems and high volume (as I recall). I really again think it is a matter of implementation. I sent a speaker to Tom Nousaine to measure and he said it was one of the better implementations of a leaf tweeters he had seen but "so what, there is no inherent advantage to leaf tweeters" So the issue is one of how good the designer is whether it is leaf (ribbon ) dome etc. Just my opinion though so some knowledgeable people need to weigh in such as TLS, Dennis Murhpy, Sean Olive (I sent him an email, maybe he will drop by).


By the way, if I had to guess why Infinity abandoned ribbons it is a simple answer, they were bought by Harman and it did not fit in with their manufacturing abilities. To my knowledge, Harman has never manufactured ribbons but I think they at least use to manufacture all their dirvers.

Infinity Systems is a manufacturer of loudspeakers founded by Arnie Nudell, John Ulrick and Cary Christie in 1968. Since 1983, Infinity has been part of the Harman International Industries group

 

[j_garcia]

I've heard some really excellent speakers that use ribbons, but most of my favorites do not. I can't say that I have a preference, because it really comes down to the specific speaker and how it sounds - if it was designed well and sounds good, then driver type doesn't really matter to me.

 

[highfigh]

I worked at an Infinity dealer when they transitioned from ribbon to polycell domes and I still don't like the polycell much. At the time, rare earth magnets became really expensive, IIRC. That alone made them prohibitively expensive. In the early '80s, a replacement tweeter cost a dealer over $100 each and that was more than most people wanted to spend. Also, the Japanese electronics companies were in the middle of a specs race with their receivers and while they put out a bunch of power, it wasn't necessarily clean. People launched tweeters all the time and Infinity had to eat the cost on far more than they did after they switched to domes because the ribbons didn't handle distortion well. For good or bad, people bought what they wanted and if they liked the speakers, the receiver wouldn't always be at the same level of quality.

 

[Swerd]

Ribbon tweeters that I've heard do have a cleaner, less noisy sound to my ears. But like all broad generalizations, it depends on the ribbon tweeter and its implementation into an overall speaker design. Many ribbon drivers (but not all) used as tweeters in 2-ways, tend to have less ability to handle lower frequencies, below 3,000 Hz, limiting their use with many mid-woofers. In 3-way designs, they can be crossed at higher frequencies and avoid trouble. So how a ribbon sounds can depend on the crossover frequency.

Distortion
If I understand correctly what Zaph does with his harmonic distortion measurements, he stimulates drivers with lower frequency tones, and measures the various amounts of higher frequency harmonic distortion that results. This is done independent of any cabinet or crossover. Obviously, if a crossover filters out some or most of the primary tones that generate the worst of the harmonic distortion, the result will be quite different. Mounting a tweeter in a cabinet also has a large effect on the lower treble frequency response. So talking of a tweeter’s harmonic distortion generically, without considering cabinet or crossover may be painting with too broad a brush.

Vertical dispersion
In my opinion, too much is made of the issue of vertical dispersion. Taller ribbons with the ability to cover the upper midrange and higher do have limited vertical dispersion, but the small sized ribbon drivers that serve as tweeters are hardly effected by this.

Flat Impedance Curve
Most ribbon tweeters that I seen have little or no rise in impedance as frequency increases. This essentially flat impedance vs. frequency curve makes crossover design much easier than with a dome driver with a typical voice coil.

 

[randyb]

I worked at an Infinity dealer when they transitioned from ribbon to polycell domes and I still don't like the polycell much. At the time, rare earth magnets became really expensive, IIRC. That alone made them prohibitively expensive. In the early '80s, a replacement tweeter cost a dealer over $100 each and that was more than most people wanted to spend. Also, the Japanese electronics companies were in the middle of a specs race with their receivers and while they put out a bunch of power, it wasn't necessarily clean. People launched tweeters all the time and Infinity had to eat the cost on far more than they did after they switched to domes because the ribbons didn't handle distortion well. For good or bad, people bought what they wanted and if they liked the speakers, the receiver wouldn't always be at the same level of quality.

Interesting information. Thanks.

 

[JerryLove]

So ribbons are, speaking in generalities, "better" but only with high crossovers.

That would explain why Infinity used them in 3-way and 4-way designs, and why they have not been generally popular in 2-way designs.

But I don't see that they reliably show up in even 4-way setups, even when price ceases to be a real concern.

I know there's often not "one best answer", but I'm trying to understand the trade-offs here and compare that to what I see in the market.

 

[cschang]

Infinity did have a popular 2-way bookshelf that used an EMIT tweeter:

http://www.bobbyshred.com/infinity/R0.1.html

Myself...I don't have a lot of experience with different ribbon tweeters/implementations. Two that come to mind are the VMPS 626R, which I liked, and Dali Ikon/Mentor, which I did not.

Interesting thread that I will keep an eye on.

 

[Swerd]

So ribbons are, speaking in generalities, "better" but only with high crossovers.

I would reword that to say " but only with high enough crossovers".

I believe that ribbon tweeters are a relatively new and still developing technology. If their performance and reliability improves and the price comes down, we'll see lots more speakers with ribbons in the future. A lot of speaker designers may be waiting for this development to reach a plateau before they adopt it.

Dome tweeters, in comparison, are a mature design with little or no major recent developments. They are well understood and easily used by most speaker designers.

 

[randyb]

Infinity did have a popular 2-way bookshelf that used an EMIT tweeter:

http://www.bobbyshred.com/infinity/R0.1.html

Myself...I don't have a lot of experience with different ribbon tweeters/implementations. Two that come to mind are the VMPS 626R, which I liked, and Dali Ikon/Mentor, which I did not.

Interesting thread that I will keep an eye on.

Another highly rated but very expensive speaker with a ribbon is the Aerial 20T v. 2. Interestingly, I think it is the only Aerial with a ribbon.

 

[tom67]

Try these beauties.....

I was reading one of the neat quasi-technical documents infinity put out for one of it's older speakers. In the doc (need to re-find) they discuss at length why they were using EMIT and EMIM ribbons, and the importance of the cabinet shape they were using (curved trapezoid).

From what I can see: Infinity has essentially abandoned ribbons and that cabinet shape for conventional rectangles and dome tweeters (and cone mids).

So my question, in addition to "why did Infinity change course" (if anyone knows), is "what are the major disadvantages of ribbon tweeters?". Why (other than price) do the majority of builders choose domes instead?

Krypton Emit tweeters and wonderful wood veneer cabinets...draw rave reviews......better than any dome tweeters and a lot less than Green Mountains to try.........May also have return priviledges...

http://www.htd.com/Products/level-three-speakers/Level-THREE-Bookshelf-Speakers

 

[Swerd]

Infinity did have a popular 2-way bookshelf that used an EMIT tweeter:

http://www.bobbyshred.com/infinity/R0.1.html

That 2-way has a 5" woofer with a crossover point at 3,000 Hz. At least its consistent with my idea.

 

[JerryLove]

I believe that ribbon tweeters are a relatively new and still developing technology. If their performance and reliability improves and the price comes down, we'll see lots more speakers with ribbons in the future. A lot of speaker designers may be waiting for this development to reach a plateau before they adopt it.

It's been about 30 years since Infinity started using them throughout their reference line. Looking at PE, there's great variety and relatively low cost.

Dome tweeters, in comparison, are a mature design with little or no major recent developments. They are well understood and easily used by most speaker designers.

But then why haven't the most experienced of the design houses picked up on them? B&W for instance, who certainly is not above some R&D (diamond tweeters). It seems the answer on Infinity abandoning is "they got expensive and when they got cheap again, HK wasn't interested", though given the amount of audio science from HK's top engineers, I don't see how they got overlooked.