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Thread: Sierra Tower Specifications, Measurements, Pricing

  1. #1
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    Default Sierra Tower Specifications, Measurements, Pricing

    We are pleased to announce that our next batch of Sierra Tower cabinets are in full production. Pre-order pricing is available from now through when we receive the next batch.

    (availability last updated on 12/20/2011)

    All options now available for pre-order. Please see here for details and pricing: http://www.ascendacoustics.com/pages...s/SRT/srt.html

    *RAAL ribbon tweeter upgrade will add $350 for each speaker. This price is expected to increase significantly once our current supply runs out.

    Please call or send an email if you would like to place an order or if we can be of any assistance.


    Sierra Tower Specifications





    Measurements:

    All measurements taken using DRA Lab’s MLSSA system with RCAI, calibrated ACO Pacific 7012 ½” free field measurement microphone with associated pre-amp and power supply and an automated Outline turntable.

    Full-range quasi-anechoic on-axis frequency response

    Microphone distance is 1 meter with calibrated sensitivity





    Horizontal and vertical off-axis graphs plus listening window

    Listening window is the averaged response of 5 separate measurements, on-axis, +/- 15 degrees horizontal and +/- 15 degrees vertical. In the case of floor-standing loudspeakers, we prefer to use +/- 10 degrees vertical as this more closely represents a real-world listening environment. Note: due to the measurement technique, the response below 250Hz is invalid, as represented by the above and below horizontal green bars.





    Polar Response

    5 degree increments from 0 degs to a full 90 degs off-axis. Note how the critical midrange response remains linear and consistent with uniformly decreasing spl as frequency increases. Also note the lack of tweeter bloom as far off-axis as 45 degrees. This represents an exceptional off-axis response.





    Impedance and electrical phase

    Note the extremely clean impedance response (free from wrinkles which would represent various forms of resonances) and linear phase with minimal phase angles. The mild phase angles ensure that this speaker is an easy load for even basic receivers.





    Energy Time Curve

    This measurement is a good indication of overall transient accuracy and stored energy. The graph displays the decay time of a full range impulse. The impulse occurs at 3ms and decreases uniformly to the noise floor (-45db) by 4ms. This represents a decay time of 1ms, which is superb. Large diameter woofer cones, woofers and tweeters with poorly designed motor systems and/or heavy mass and poorly constructed cabinets will often contribute to far greater decay times which damage transient accuracy, coherency and overall resolution.





    Cumulative Spectral Decay

    This measurement is similar to the energy time curve but displays a 3 dimensional view such that we can examine the decay time with reference to frequency. It is an exceptional tool to reveal transient accuracy and indicate various problem areas with respect to resonance and stored energy. The CSD of the Sierra Tower is exceptionally clean with good uniformity.

    Last edited by davef; 12-20-2011 at 06:27 PM.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  2. #2
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Reserved...
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  3. #3
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    I guess the RAAL measurements are to follow...

  4. #4
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    three things:
    -great job with all the measurements and especially the descriptions-- that's very helpful; the 1ms decay is impressive
    -why is frequency response graph listed at 8ohms? typo i assume
    -somehow i thought it was more of a 6ohm speaker, I guess i misread that in one of the previous posts as it states 4ohm in the description; do you feel average AVR's marketed for 6-8ohm use will be ok? I feel like you have answered that before but i want to reask it i guess. denon's and onkyos, etc, can do most 6ohm loads but 4ohms may be pushing it a bit-- maybe someone who has a similar setup can chime in on how the amp handled it

  5. #5
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Quote Originally Posted by scape View Post
    three things:
    -great job with all the measurements and especially the descriptions-- that's very helpful; the 1ms decay is impressive
    -why is frequency response graph listed at 8ohms? typo i assume
    -somehow i thought it was more of a 6ohm speaker, I guess i misread that in one of the previous posts as it states 4ohm in the description; do you feel average AVR's marketed for 6-8ohm use will be ok? I feel like you have answered that before but i want to reask it i guess. denon's and onkyos, etc, can do most 6ohm loads but 4ohms may be pushing it a bit-- maybe someone who has a similar setup can chime in on how the amp handled it
    Im definitely not Dave lol, but I completely agree with the first part, theyre very helpful, just looking at a graph by itself doesn't give nearly as much meaning and vice-versa, so both compliment each other very well.

    Looking at the impedance graphs, it does seem like it averages around 6ohms, which is normal as you said. You should be fairly ok as long as you have a competent avr anyhow; the stated 4ohm average looks like it might be a typo, cuz that might mean there are dips around ~2ohms even, just based on that. (hm, rethinking, I can't imagine Dave would release a speaker that a lot of avrs would have difficulty driving.. but thats just me).

    again, kudos to Dave for everything

    edit: ok, i see where things were confusing.. reading back a few pages in the tower thread, the towers minimum impedance is rated @ 4ohms, but on the specs it says the average impedance is 4ohms.. oh well, just something to correct is all
    Last edited by choirbass; 11-07-2011 at 03:33 AM.
    Sierra-2
    DC-1
    UMC-1
    UPA-7

  6. #6
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Can a 8W SET Amp be used to drive the towers ??

  7. #7

    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Price is per pair, yes?

    Thanks!

  8. #8
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Quote Originally Posted by Omanian View Post
    Can a 8W SET Amp be used to drive the towers ??
    Unless I'm misunderstanding what the amp is even after a quick search on google, a minimum of 25w/each is recommended (@8 ohms?). I'm sure you 'maybe could' use 8w (@8ohms again?) per speaker at very low volumes (keeps demands on the amp down/prevents clipping/keeps the amp from going into protection mode if it offers that, etc). But even still, I really wouldn't if you have other options.. You risk damaging the speakers, most of all.

    Quote Originally Posted by charlie12125 View Post
    Price is per pair, yes?

    Thanks!
    yep.
    Last edited by choirbass; 11-07-2011 at 12:26 AM.
    Sierra-2
    DC-1
    UMC-1
    UPA-7

  9. #9
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Quote Originally Posted by parimento1 View Post
    I guess the RAAL measurements are to follow...
    I have completed an extremely comprehensive study comparing our NrT dome to the RAAL ribbon and I hope to publish it later this evening. This might be the first of its kind...

    Frequency response, polar response, impulse response and stored energy are examined in detail and I believe the results will objectively document what most people (including myself) have difficulty in describing the differences they hear. I suspect this study will be widely referenced and because of this, it will be available to forum members only in a PDF document.

    This was not an easy task as I had to use our very best microphone (ACO 7012) which has a calibrated bandwidth up to 40 kHz. I then also had to reprogram all of our standard measurements to accommodate the additional bandwidth and I then increased FFT size to 32768 points, which gives us nearly 1Hz resolution. Achieving this type of resolution and bandwidth requires very specific gear that costs a fortune, thus the information will be made publicly available to our forum members only. Of course, our forum membership is open to everyone

    I will say this in advance, I was surprised at the results – this particular RAAL ribbon tweeter is as close to a near perfect high frequency transducer as I can imagine. More specifically, I honestly can’t imagine that I will ever have the privilege of measuring anything better. Forget reading subjective descriptions of it… I have documented it in detailed measurements
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  10. #10
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    Default Re: Sierra Tower Specifications, Measurements, Pricing

    Quote Originally Posted by scape View Post
    -why is frequency response graph listed at 8ohms? typo i assume
    Not a typo, the impedance rating printed on that graph is not an actual measurement -- it is simply a calibration setting of the MLSSA system we use such that when calculating sensitivity, 2.83V is used as the output - which is the industry standard for calculating sensitivity.

    Quote Originally Posted by scape View Post
    -somehow i thought it was more of a 6ohm speaker, I guess i misread that in one of the previous posts as it states 4ohm in the description; do you feel average AVR's marketed for 6-8ohm use will be ok? I feel like you have answered that before but i want to reask it i guess. denon's and onkyos, etc, can do most 6ohm loads but 4ohms may be pushing it a bit-- maybe someone who has a similar setup can chime in on how the amp handled it
    Impedance curves vary with frequency and there is really no "standard" when it comes to rating the impedance of a loudspeaker. As you can see by the impedance measurement, the Sierra Tower's impedance is a stable 4 ohms from about 20Hz to 1kHz (almost 6 octaves) and from there the impedance remains at 8 ohms and above for 4 1/2 more octaves. Technically, we could rate this speaker at a 6 ohm load without issue. The key is not so much the actual impedance but the phase angle at the lower impedances. In the case of the Sierra Tower, the phase angles are extremely mild and the Towers can be driven by any receiver...

    Technically, this is an easier loudspeaker to drive than our Sierra-1.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

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