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Thread: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

  1. #11
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    The main benefit over the 2EX would be the tower’s midrange, since it’s a 3 way.

  2. #12
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by davef View Post
    The advantages of the 70-20 ribbon over the ribbon in the Sierra-2EX are:

    * More than double the resonating surface area
    * ability to be crossed as low as 1.8kHz
    * much higher power handling
    * lower distortion
    * a more linear response both on and off-axis
    * due to a unique ribbon element damping system, unique to the 70-20 (I am under NDA not to disclose), the ribbon element is more durable and significantly less susceptible to the damaging effects of transverse waves (which can be caused by amplifier clipping)
    What frequency are they crossed over at on the Sierra Towers?

  3. #13
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by Shazb0t View Post
    What frequency are they crossed over at on the Sierra Towers?
    In the towers, the 70-20 ribbon is crossed to the midrange at ~ 2kHz.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  4. #14
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by davef View Post
    In the towers, the 70-20 ribbon is crossed to the midrange at ~ 2kHz.
    Is the crossover point the same for the RAAL Horizon?

  5. #15
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by Shazb0t View Post
    Is the crossover point the same for the RAAL Horizon?
    Yes -- exactly the same.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  6. #16
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by davef View Post
    Yes -- exactly the same.
    I was looking at this review:
    https://www.audiosciencereview.com/f...-review.15199/

    Hard to see that they are crossed at ~2kHz. Maybe more around 2.5kHz from the vertical directivity index and polar plots. I also could be convinced something is happening at 3.5kHz, lol. Were there changes to the crossover point made over the production run? Thanks for taking the time to respond.
    Last edited by Shazb0t; 08-26-2021 at 10:46 AM.

  7. #17
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by Shazb0t View Post
    I was looking at this review:
    https://www.audiosciencereview.com/f...-review.15199/

    Hard to see that they are crossed at ~2kHz. Maybe more around 2.5kHz from the vertical directivity index and polar plots. I also could be convinced something is happening at 3.5kHz, lol. Were there changes to the crossover point made over the production run? Thanks for taking the time to respond.
    Sorry - but no, anyone in that thread thinking they can determine the crossover points in this speaker by looking at the DI would be sadly mistaken. Too many back seat drivers these days.

    This is what makes the Horizon and our Towers quite magical.. There is a near perfect horizontal directivity match between the midrange we use and our version of the RAAL 70-20xram at where they cross. I discussed this in the polar response measurements here many many years ago.

    http://www.ascendacoustics.com/pages...on%20Tower.pdf

    Seems a bit silly to use a tweeter that is specifically designed to be crossed at ~1800Hz, costs about 5x more than the RAAL in the S2, and cross at 3.5kHz? Doesn't it? I mean, we could save a fortune and just go with the S2 RAAL ribbon in our towers and horizon if I wanted to cross that high.

    Of course, if I did that, the horizontal directivity wouldn't be nearly as impressive.

    The little ripple at 3.5kHz is just a minor reflection caused by the phase plug on the midrange driver.

    There have been no crossover changes in the Horizon or our towers since their introduction.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  8. #18
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by Shazb0t View Post
    I was looking at this review:
    https://www.audiosciencereview.com/f...-review.15199/

    Hard to see that they are crossed at ~2kHz. Maybe more around 2.5kHz from the vertical directivity index and polar plots. I also could be convinced something is happening at 3.5kHz, lol. Were there changes to the crossover point made over the production run? Thanks for taking the time to respond.
    Hey Shaz,

    You got lucky today as we built a ribbon horizon for a customer that we didn't yet clean and pack for shipping.

    IMG_2663.jpg

    It took some work on my end, I typically don't like moving fixed microphones around but this time I actually carefully measured its position so placing it back exactly where it belongs wasn't too bad

    Here are the close mic response measurements for both the twt and mid. You can clearly see where they acoustically cross. I do apologize for poor quality, to save time, I took a pic of the monitor with my iPhone. Otherwise I would have had to find a USB thumb drive to transfer the files to this computer, and I have misplaced/lost every thumb drive I have ever owned

    IMG_2662.gif

    You can also see the reflection caused by the phase plug on the woofer in the woofer response, at ~3.5kHz.

    It is also important to understand that since these are close mic response measurements and all drivers are connected, the tweeter response is somewhat influenced by the woofer. Which is why you see the tweeter roll off steeply and then start rising again at ~1600Hz. That rise is caused by the woofer...

    There is no tweeter influence in the woofer response because I put a shield over the ribbon for that measurement.

    Hope this makes sense.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  9. #19
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Makes perfect sense. Thanks for your effort in providing a very thorough response. The directivity match from the midrange to tweeter is clearly very impressive as also shown in the Klippel directivity measurements!

  10. #20
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    Default Re: Sierra Towers (RAAL) vs Sierra 2 EX's as front L/R

    Quote Originally Posted by Shazb0t View Post
    Makes perfect sense. Thanks for your effort in providing a very thorough response. The directivity match from the midrange to tweeter is clearly very impressive as also shown in the Klippel directivity measurements!
    Very welcome Shaz. I wish more people would take the approach you did and simply ask the manufacturer / engineer rather than attempting to draw conclusions from measurements.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

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