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Thread: S70 Alpha I - Dèjá Vu

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    RIP 2011 Zilch's Avatar
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    S70 Alpha I - Dèjá Vu

    Like L100 et al. with overly forward midrange and rolled-off highs, S70 MF and HF controls "interact" in measurements due to phase interference of drivers running free above their respective highpass filters.

    If there's a sweet spot, only JBL's "Tilt-A-Speaker" might find it; it sounds different from every angle, and best, generally, with the midrange dialed nearly off.

    Bass is extended, but somewhat flabby. No weights on the PR12 passive radiator.

    Internal dims: 29.5" W x 22.5" H x 12" D = 4.61 cuft.
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    Maron Horonzakz
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    Is,nt that cabinet upside down?

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    So, forgive me, I've never seen one of these. Is it basically a domestic double-woof 4311? By your measurements, it seems to be best used as driver donor . . .

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    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Zilch View Post
    Like L100 et al. with overly forward midrange and rolled-off highs, S70 MF and HF controls "interact" in measurements due to phase interference of drivers running free above their respective highpass filters.

    If there's a sweet spot, only JBL's "Tilt-A-Speaker" might find it; it sounds different from every angle, and best, generally, with the midrange dialed nearly off.
    "Tilt-A-Speaker"

    You are obviously not getting a representative measurement of this speaker. I am not suggesting that the S70 Alpha I is a world class monitor, but I am sure it is more listenable than these plots would suggest.

    To get a better idea of how it actually measures (sounds) you should take it outdoors and measure it at some distance. The L100 has the same problems. You can get a dozen different curves when measuring it at one meter.

    Couple of measurement questions. Why are you using the Half-Hanning window (do you have a relatively poor signal to noise ratio?) and why sinusoidal for the nearfield woofer measurements.


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    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by Maron Horonzakz View Post
    Isn't that cabinet upside down?
    Yes, and elevated, to position the drivers of interest midway between the floor and ceiling for minimum interference from their reflections, and in MLS to allow the maximum time window width.

    Quote Originally Posted by Beowulf View Post
    So, forgive me, I've never seen one of these. Is it basically a domestic double-woof 4311? By your measurements, it seems to be best used as driver donor . . .
    One woofer with passive radiator. As Mr. Widget suggests, it does not sound as bad as it measures, once the mid driver is substantially attenuated.

    In theory, the in-line alignment of the mid and high drivers is "better" than that of L100/4311, but with only highpass filters on them, I'm not so sure that the cluster arrangement isn't superior in terms of minimizing phase interference, or, at least, rendering it least objectionable. The earliest "bookshelf" monitor versions using these drivers were also vertical in-line, but had full bandpass filters.

    Quote Originally Posted by Mr. Widget View Post
    To get a better idea of how it actually measures (sounds) you should take it outdoors and measure it at some distance. The L100 has the same problems. You can get a dozen different curves when measuring it at one meter.
    The only way I could get a reasonable indication of anything at 1M was by turning off one of the drivers. It's apparent there's still major interference between the free-running woofer and both/either the mid and/or tweeter. The violet curves are what the woofer is doing in each case, with the drivers off.

    Clearly, there's substantial improvement to be pursued with a more sophisticated crossover, as suggested in earlier threads by the member formerly known as Giskard, and driver swaps. Regarding L100/4311 upgrades, I've said many times, "Leave them be," from my own experience, but it appears likely that these S70s can be made into much more than what they are.

    Quote Originally Posted by Mr. Widget View Post
    Couple of measurement questions. Why are you using the Half-Hanning window (do you have a relatively poor signal to noise ratio?) and why sinusoidal for the nearfield woofer measurements.
    Half-Hanning was suggested by an expert who saw some of my early MLS postings. We can discuss the details the next time we meet.

    Sinusoidal gets down to 10 Hz in CLIO. Let's talk about MLS vs. gated and delayed sinusoidal next time, too.

    I was hoping that the "CLIO Clinic" thread would get into this level of discussion, but it didn't happen, alas....

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    Senior Member Skywave-Rider's Avatar
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    Part them out and sell me one of the woofers.






    JK, I'm curious to see what you do with the x-over.

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    Senior Member Skywave-Rider's Avatar
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    That'd be cool with a horn/waveguide in place of the mid and tweeter?

    Stupid question: If the bass is flabby, couldn't some internal volume be eliminated -- and would that tighten it up?

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    RIP 2011 Zilch's Avatar
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    If the baffle were tilted back as in Olympus, for example, a horn upgrade might be worth considering.

    As constructed, they would play to the kneecaps of the listener.

    [I don't consider these suitable canditates for stand mounting.... ]

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    Senior Member Skywave-Rider's Avatar
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    Come on! Stack 'em high and watch 'em fly!!!

    Or maybe asymmetrical Manta Rays?
    I know u tried those, maybe they're not so hot.

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    RIP 2011 Zilch's Avatar
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    Quote Originally Posted by Skywave-Rider View Post
    Or maybe asymmetrical Manta Rays?
    I know u tried those, maybe they're not so hot.
    My expectations exceeded the actual performance. They're just not as transparent as PTs.

    In fairness, I need to get them mounted on baffles. There's less substance to them than the Econo PT, even.... :dont-know

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    Senior Member SMKSoundPro's Avatar
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    Quote Originally Posted by Zilch View Post
    If the baffle were tilted back as in Olympus, for example, a horn upgrade might be worth considering.

    As constructed, they would play to the kneecaps of the listener.

    [I don't consider these suitable canditates for stand mounting.... ]
    What about soffit mounting above a desk or in a control booth?

    And, remove the le5 & le25, and install a ...?

    And, weighting the PR apropriately...?
    One step above: "Two Tin Cans and a String!"
    Longtime Alaskan Low-Fi Guy - E=MC² ±3db

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    Senior Member SMKSoundPro's Avatar
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    How about a little smith horn and a slot?

    Sort of like a mini Westie?
    One step above: "Two Tin Cans and a String!"
    Longtime Alaskan Low-Fi Guy - E=MC² ±3db

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    Senior Member Skywave-Rider's Avatar
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    Quote Originally Posted by SMKSoundPro View Post
    How about a little smith horn and a slot?

    Sort of like a mini Westie?
    That sounds like a cool idea but I wager Zilch won't like that.
    Reflections off the Smith horn. Pre waveguide performance.
    But it looks sooooo coooooool......

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