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Thread: Sierra 1, Luna or Sierra 2?

  1. #11
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    Default Re: Sierra 1, Luna or Sierra 2?

    What N Boros describes is exactly what I experienced with my Sierra-1's and my old Hsu VTF-3mk2. The Sierra-1 was more articulate in the bass region and I could tell the difference between the speaker and the sub at 80hz, I had to drop the crossover to 60hz to get a seamless integration.

    I switched to a Rythmik F15/F15HP and I was able to cross at 80hz with no issues. Now that I have Sierra-2's, 80hz still works fine. SEAMLESS!
    Last edited by curtis; 08-14-2017 at 11:58 AM.

  2. #12
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    Jun 2017
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    Default Re: Sierra 1, Luna or Sierra 2?

    Quote Originally Posted by Bruce Watson View Post
    Accuracy. Servo systems use active feedback. What that means to a subwoofer is that the sub's circuitry looks at the input coming to the sub from your signal source, then it also measures what the sub actually does (cone travel) in real-time. The difference between the two (the error signal) is then fed back into the control logic to correct the physical behavior of the cone so that it matches the input signal. So what your source asks for is what you get. Exactly.

    What it means for your system is that servo subs are typically easier to integrate with your other speakers. Makes the result feel seamless, as if your other speakers all reach down to 20 Hz themselves. It also means less distortion, particularly at high levels.

    So... more accurate, therefore cleaner, with less distortion.
    I thought the servo just let you have more output for less power.

    In which case, would the extra 125W from the S1500 compensate for this? (600W in the Rythmik, 725W in the PSA)

  3. #13
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    Default Re: Sierra 1, Luna or Sierra 2?

    Quote Originally Posted by curtis View Post
    What N Boros describes is exactly what I experienced with my Sierra-1's and my old Hsu VTF-3mk2. The Sierra-1 was more articulate in the bass region and I could tell the difference between the speaker and the sub at 80hz, I had to drop the crossover to 60hz to get a seamless integration.

    I switched to a Rythmik F15/F15HP and I was able to cross at 80hz with no issues. Now that I have Sierra-2's, 80hz still works fine. SEAMLESS!
    Seems like I should've opted for the Rythmik, I cross at 60 Hz for music and 80 Hz for HT, would rather just cross at a single frequency.

  4. #14
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    Central NC
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    133

    Default Re: Sierra 1, Luna or Sierra 2?

    Quote Originally Posted by Roen View Post
    I thought the servo just let you have more output for less power.

    In which case, would the extra 125W from the S1500 compensate for this? (600W in the Rythmik, 725W in the PSA)
    One of the "side effects" of increased accuracy is higher efficiency I think. But that's not the primary reason to implement a servo on a sub. The primary reason is accuracy, which also means less distortion, which means better integration.

    As to electrical power, there's not a direct correlation between the power available from an amplifier and the sound pressure level that the attached sub can produce. Your comparison is perhaps more apples-to-oranges than you might want.
    "If it sounds good, it is good." -- Duke Ellington

  5. #15
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    Default Re: Sierra 1, Luna or Sierra 2?

    Quote Originally Posted by Bruce Watson View Post
    One of the "side effects" of increased accuracy is higher efficiency I think. But that's not the primary reason to implement a servo on a sub. The primary reason is accuracy, which also means less distortion, which means better integration.

    As to electrical power, there's not a direct correlation between the power available from an amplifier and the sound pressure level that the attached sub can produce. Your comparison is perhaps more apples-to-oranges than you might want.
    Bah.

    Thanks for the info.

  6. #16
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    USA
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    Default Re: Sierra 1, Luna or Sierra 2?

    Quote Originally Posted by Roen View Post
    I thought the servo just let you have more output for less power.

    In which case, would the extra 125W from the S1500 compensate for this? (600W in the Rythmik, 725W in the PSA)
    Servo and "power" have no correlation. As Bruce elaborated, Servo is an advanced system that is able to measure both the woofer acceleration and woofer position in realtime. This information is than feedback into the amplifier that controls the woofer movement and instantaneously compensates. Servo enables considerably more accurate transient accuracy, lower distortion, and compensates for the aging of the woofer suspension system (compliance changes).

    I often like to make the comparison between a laser guided missile reaching its target compared to an RPG. The laser guided missile uses realtime information to continuously compensate for its flight path, where as once you fire an RPG, you just hope you aimed properly, or a giant gust of wind doesn't change the trajectory...

    In addition, higher amplifier power does not mean more output - it is really just a marketing ploy. For example, which would have more overall output, a subwoofer with a 1000 watt amplifier powering a woofer with 84dB sensitivity, or a subwoofer with a 300 watt amplifier powering a woofer with 92dB sensitivity?

    The answer might surprise you -- the 300 watt subwoofer will have TWICE the power output...

    Without knowing the sensitivity of the woofer being used in the subwoofer, amplifier power is a meaningless specification.

    Because of Direct Servo, Rythmik subs are able to use lower mass, higher efficiency woofers compared to their competitors.

    I recommend avoiding falling into that crowd the relies on "power" as some type of measure of performance. You would be exactly who they are targeting with that rather meaningless spec
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    Good Sound To You!

    David Fabrikant
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  7. #17
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    102

    Default Re: Sierra 1, Luna or Sierra 2?

    Quote Originally Posted by davef View Post
    Servo and "power" have no correlation. As Bruce elaborated, Servo is an advanced system that is able to measure both the woofer acceleration and woofer position in realtime. This information is than feedback into the amplifier that controls the woofer movement and instantaneously compensates. Servo enables considerably more accurate transient accuracy, lower distortion, and compensates for the aging of the woofer suspension system (compliance changes).

    I often like to make the comparison between a laser guided missile reaching its target compared to an RPG. The laser guided missile uses realtime information to continuously compensate for its flight path, where as once you fire an RPG, you just hope you aimed properly, or a giant gust of wind doesn't change the trajectory...

    In addition, higher amplifier power does not mean more output - it is really just a marketing ploy. For example, which would have more overall output, a subwoofer with a 1000 watt amplifier powering a woofer with 84dB sensitivity, or a subwoofer with a 300 watt amplifier powering a woofer with 92dB sensitivity?

    The answer might surprise you -- the 300 watt subwoofer will have TWICE the power output...

    Without knowing the sensitivity of the woofer being used in the subwoofer, amplifier power is a meaningless specification.

    Because of Direct Servo, Rythmik subs are able to use lower mass, higher efficiency woofers compared to their competitors.

    I recommend avoiding falling into that crowd the relies on "power" as some type of measure of performance. You would be exactly who they are targeting with that rather meaningless spec
    Double bah.

    Thanks for that.

    I think the other reason why I went with a S1500 instead of a F15HP was due to the $293 price difference. I might be having regrets now, plus the Piano Black of the F15HP would have matched my Sierra-2's much better than the black satin I currently have now.

  8. #18
    Join Date
    Jan 2016
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    8

    Default Re: Sierra 1, Luna or Sierra 2?

    Thanks everyone for the replies. I got a lot to think about.

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