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Thread: Announcement: A Sierra-1 add-on enhancement!

  1. #1
    Join Date
    Aug 2003
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    Lightbulb Announcement: A Sierra-1 add-on enhancement!

    I am most pleased to announce a new add-on product for our highly regarded Sierra-1 loudspeakers.

    Introducing Q-Plugs... (sorry for the lousy pics )

    **Please use this link to order: Sierra-1 Q-Plug Kit


    In short, 2 specially designed and custom tooled port plugs made of an open cell acoustic foam. Q-plugs allow “tuning” of the Sierra-1 bass response to allow more flexibility in optimizing in-room performance while dramatically increasing placement options.

    Q-Plug A
    Simply plugging the port of a properly designed ported loudspeaker is generally a bad idea. A woofer that is designed for a ported enclosure will act differently when installed in a sealed enclosure. The compliance of the woofer is not designed to see the internal pressures created by a sealed enclosure and the speaker then becomes overdamped, subjecting the woofer to greater excursions (often exceeding its mechanical limits) and pre-mature bass roll-off. You can also end up with a higher than normal impedance peak at system resonance.

    However, the advantages to plugging a port can outweigh the disadvantages if the speaker is going to be positioned so that the port tube is close to a wall or the speaker is in an enclosure. The challenge we faced was how to offer the flexibility of plugging the port without crippling our woofer which is fully optimized for a ported design.

    The solution was to transform the Sierra-1 into an aperiodic enclosure, an enclosure that allows a specific amount of pressure to be released through the cabinet. This allows precise control of woofer damping resulting in improved bass response compared to simply sealing the port while also lowering the high impedance peak.


    notice the reduction in the impedance peak compared to a "sealed" Sierra-1

    Q-Plug A consists of a cylindrical tube with a 5mm thick “end cap” made of acoustic foam that allows a specific amount of air to pass through.

    It is recommended to use Q-Plug A when the Sierra-1 will be wall mounted or within several inches of the wall. Use of this port plug can also improve subwoofer integration as the in-room response of the speaker changes to -3dB at 60Hz with a 12dB/octave roll-off as compared to a stock Sierra-1 which is approximately -3dB at 40Hz in room with a sharp 24dB/octave roll-off.


    notice the reduction in the bass bump caused by close location to a wall


    in-room response comparing stock Sierra-1 with Q-Plug A


    in-room response comparing a "sealed" Sierra-1 with Q-Plug A


    Q-Plug B
    This plug was designed to squeeze every last ounce of performance out of the Sierra-1, especially when used in smaller rooms or where room modes cause over emphasized bass. It consists of the same cylindrical tube as Q-Plug A but without the end-cap.

    Q-Plug B creates a mass loaded damped port, lowering the port tune frequency by 10Hz while also damping port tube resonances and dramatically reducing port noise. When compared to a stock Sierra-1, we get 3dB less output in the 50-70Hz range and 3dB more output in the 30Hz range. The speaker will have less “punch” but a deeper bass response. The woofer will contribute more to the bass output which can result in a cleaner and even more articulate response. One interesting phenomenon that I noticed was that imaging was improved and the soundstage was deepened. I attributed this not to the deeper bass response but to the damping of spurious out-of-phase port noises that can cause subtle comb filtering.



    in-room response comparing stock Sierra-1 with Q-Plug B

    A quote from one of our Beta-Testers:

    “Stereo 2.0
    No Plug: Very full sound, punchier, hits chest, a tad boomy at loud volume levels. Room and entertainment center resonate.
    Plug B: Very full sound, deeper and cleaner, hits chest but not as much as with no plug. Only entertainment center resonates.
    My preferences varied a bit depending on the song being played…In the end I chose leaving Plug B in, with and without sub.”



    In Summary:

    Our new Q-plugs greatly expand the versatility and placement options of the Sierra-1. We chose to avoid using additional crossover components to offer different bass alignment options. Adding additional crossover components causes an increase in distortion and phase anomalies and is against our “less is more” design philosophy for the Sierra-1. Instead, we came up with a unique solution that changes bass alignments without adding any additional negative effects.

    Q-Plug A: Recommended when the Sierra-1 will be positioned so that the rear port tube is close to a wall, wall mounted, or when the speaker is placed in an enclosure. Also recommended to improve integration with a subwoofer and it is the ideal choice if you want to use a subwoofer but do not have bass management for the speakers (speakers full range with a subwoofer)

    Q-Plug B: Recommended in smaller rooms where room modes might cause over emphasized bass. These plugs will provide a deeper more articulate bass response with less punch and possibly less boom, and can also enhance imaging and soundstaging.

    These plugs will be sold as add-on kits:

    Pair Q-Plug kit (4 plugs, 2 of each) = $31.00, includes domestic shipping

    Center Q-Plug kit (2 plugs, 1 of each) = $19.00, includes domestic shipping

    Pair + Center kit (6 plugs in total, 3 of each) = $43.00, includes domestic shipping

    We will be setup for online purchasing within the next 24 hours. Shipping will begin immediately

    Enjoy!
    Last edited by davef; 12-19-2008 at 04:02 AM.
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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

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