The RAAL goes down lower, and without a highpass filter and padding, we'll never know if they sound the same at the same job. That RAAL is only highlighting the importance of midrange, which it is far more capable of producing. I would have to cross the Fountek to another driver to accomplish the same or likely better fidelity than the RAAL on it's own. The side-by-side is honestly silly without those constraints. Otherwise it's a fine demonstration of each driver. The RAAL plays much better alone than I would've expected.
Older data sheets stating 15um ribbon thickness but GRS ribbons saying 30um thickness . So I think they made a sandwich ribbon by pressing them together to get them kinda cold welded and make them more robust!
Any changes to the internal transformer ... maybe , someone should investigate here to clarify (thanks) .
The internal damping material should have a dominant influence of the perceived sound ... even more so than dome tweeters because of the very thin diaphragm! In that perspective a thicker ribbon is better ... of course a true dipole ribbon (like the special RAAL dipole version) is the optimum and should be used as a reference for comparison .
Ribbons are fascinating devices they are the holy grail of audio!
I am still waiting for a tru beryllium ribbon hitting my ears one fine day ...
just dreaming!?
Any changes to the internal transformer ... maybe , someone should investigate here to clarify (thanks) .
The internal damping material should have a dominant influence of the perceived sound ... even more so than dome tweeters because of the very thin diaphragm! In that perspective a thicker ribbon is better ... of course a true dipole ribbon (like the special RAAL dipole version) is the optimum and should be used as a reference for comparison .
Ribbons are fascinating devices they are the holy grail of audio!
I am still waiting for a tru beryllium ribbon hitting my ears one fine day ...
just dreaming!?
Many years ago I have read in a book if you cut off all frequencies above 700Hz it is very hard to detect if a violin is playing or a flute!
Years later I build a 2way speaker using SEAS ER18RNX and VIFA 25mm soft metal dome special selected , Fs-800Hz . 20 Liter Box tuned to 40Hz . BSC 3dB . Crossover at 800Hz using 2nd LPF and 3rd HPF (acoustic-electric slope) .
Listening without tweeter was a relevation! Without tweeter it was nearly impossible to recognize which singer is performing as long as their style does not reveal them! (Zappa/Dylan etc)
So saying midrange is the most important in a speaker must be questioned to some degree!
Years later I build a 2way speaker using SEAS ER18RNX and VIFA 25mm soft metal dome special selected , Fs-800Hz . 20 Liter Box tuned to 40Hz . BSC 3dB . Crossover at 800Hz using 2nd LPF and 3rd HPF (acoustic-electric slope) .
Listening without tweeter was a relevation! Without tweeter it was nearly impossible to recognize which singer is performing as long as their style does not reveal them! (Zappa/Dylan etc)
So saying midrange is the most important in a speaker must be questioned to some degree!
Nothing better than making new experiences 
Btw - combining beryllium domes with fabric (coated) as a suspension seems to me the biggest contradiction ever!
Manufacturing drivers must be like gold-mining today if you are located in asia!
Why don't we use beryllium wonderdomes in our car speakers?
Must like sound in heaven!
Oh Lord please give me a Mercedes Benz
Btw - combining beryllium domes with fabric (coated) as a suspension seems to me the biggest contradiction ever!
Manufacturing drivers must be like gold-mining today if you are located in asia!
Why don't we use beryllium wonderdomes in our car speakers?
Must like sound in heaven!
Oh Lord please give me a Mercedes Benz
Sig vs RS: Smoother frequency response in the mid band, but worse harmonic distortion.
The freq resp of the Sig 4 inch is much better than the $300 Scan Speak Illuminator model!
Distortion? Not an issue until you got bat ears
The disto argument is only that the buyers of expensive stuff have something to complain about if something is rivaling their territory!
sig series is a heaven send for well gounded normal speaker builders ...
Btw - a new OMNIMIC v4 is coming!
Distortion? Not an issue until you got bat ears
The disto argument is only that the buyers of expensive stuff have something to complain about if something is rivaling their territory!
sig series is a heaven send for well gounded normal speaker builders ...
Btw - a new OMNIMIC v4 is coming!
Show me woofers with better FR's for any kind of money :
https://www.parts-express.com/Themes/Default/images/PDP/295-656/295-656 FRD.JPG
https://www.parts-express.com/Themes/Default/images/PDP/295-658/295-658 FRD.JPG
https://www.parts-express.com/Themes/Default/images/PDP/295-656/295-656 FRD.JPG
https://www.parts-express.com/Themes/Default/images/PDP/295-658/295-658 FRD.JPG
@Marveloudio
I honestly don’t see what’s so exciting about the Sig270. Apart from new and shiny.
let’s see how it measures independently.
You could have been enjoying this 10”- it’s has been around for decades
as used by Linkwitz, Krevskovsky, Carmody etc,
also a healthy x-max of around 8.3mm. US$60.
Don't Know What You Got(Till It's Gone)
I honestly don’t see what’s so exciting about the Sig270. Apart from new and shiny.
let’s see how it measures independently.
You could have been enjoying this 10”- it’s has been around for decades
as used by Linkwitz, Krevskovsky, Carmody etc,
also a healthy x-max of around 8.3mm. US$60.
Don't Know What You Got(Till It's Gone)
SLS drivers are still available:
https://www.soundimports.eu/en/peerless-by-tymphany-sls-p830668.html
https://www.soundimports.eu/en/peerless-by-tymphany-sls-p830668.html