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Chane L3c Review

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  • BufordTJustice
    replied
    Originally posted by kabin View Post
    Wow, it covers some frequency. Thanks for taking the time to educate us. Impressive indeed!
    It has such a wide usable bandwidth that it’s nearly a hybrid driver; combining some attributes of a good dome midrange with no meaningful sacrifices made to tweeter performance.

    SBA calls it a “29mm ring dome”. However, if you measure it according to industry standard practices (from the midpoint of the surround), it’s actually a 37mm driver. That’s a 1.46” driver. Nipping at the heels of some actual 2” midrange (dome and ‘flat’) drivers for performance in that regime, while leaving absolutely nothing on the table up to nearly 30khz. No standard dome could accomplish such a thing with a diaphragm that diameter, even with exotic materials like diamond or beryllium. Except for a ring radiator with a silk diaphragm.

    For the folks who wonder “why not make every model a three way”.... well you’re about to find out why that wasn’t necessary for the L3 and L3c. 😉😎👍
    Last edited by BufordTJustice; 01-03-2021, 03:03 AM.

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  • kabin
    replied
    Wow, it covers some frequency. Thanks for taking the time to educate us. Impressive indeed!

    Leave a comment:


  • BufordTJustice
    replied
    Originally posted by kabin View Post
    Unrelated question - is there a purpose for the dimple on the tweeter cover? Add strength to the cover or focus sound?
    It’s actually a central, internal anchor point for the diaphragm.

    When you keep in mind that the two founders of SBA were the engineers behind the ScanSpeak Revelator driver Series, you realize that they identified the shortcomings of the current Scan speak ring radiator tweeters. They focused on motor linearity, distortion reduction, increasing bandwidth, increasing native sensitivity, and production consistency. They succeeded.

    But Scan holds the patent for the small pointy thing that protrudes from the center of their ring radiator tweeters. It’s actually just a phase plug. So the engineers at SBA devised a different diaphragm profile. They made their driver with significantly more radiating area and contoured the face of the tweeter dome, with that center anchor point, in such a way that a phase plug wasn’t even needed anymore.

    And we haven’t even dug into the enormous amount of R&D they have put into their highly effective damped rear chambers. This means more linear response, lower f3, much reduced distortion, and better phase performance at the top and bottom of the driver’s operating band.

    And, kinda nothing’s changed at Scan since they left. Bit of a brain drain. ;)
    Attached Files

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  • Chane M&C
    replied
    Originally posted by kabin View Post
    Unrelated question - is there a purpose for the dimple on the tweeter cover? Add strength to the cover or focus sound?
    That dimple is on the tweeter diaphragm itself. It anchors the apex of the dome to the damper pad over the pole vent, making the tweeter a ring radiator. High extension is excellent and dispersion is controlled nicely. You can see how low this driver goes too - 600Hz fundamental resonance. Very useful.

    Click image for larger version

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    (A long time ago we used to burn a small hole in the dome tip and paint a ring around it in heat sink compound. Really cleaned up the sound. The ringdome achieves a similar effect, only in a far better tweeter...)

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  • kabin
    replied
    Unrelated question - is there a purpose for the dimple on the tweeter cover? Add strength to the cover or focus sound?

    Leave a comment:


  • BufordTJustice
    replied
    Originally posted by GUTB1 View Post

    Well, you're right of course. I do find it silly that speakers of Wilson's price don't use ribbons, and in fact appear to use off-the-shelf drivers. Tekton being budget speakers I can understand. I guess that also answers the question: I can't expect high-end parts in a budget speaker, which the L still is -- on the higher end of budget DIY-type speakers, but still. I supposed the use of ribbons in the A series set an unrealistic precedent when you try getting into higher performance while controlling costs.
    We need to get aligned before productive discourse can continue.

    1) Nearly every one of Wilson’s drivers are custom made for Wilson, with the odd top-tier ScanSpeak or SEAS driver used across several lines. You know, the Scan/SEAS drivers that cost $800 each. That kinda thing.

    2) Wilson actually has made an entire video on why they chose to employ a dome instead of a ribbon; it’s called their Convergent Synergy Tweeter. For speakers that cost $40k/pair and up (all the way up to $350k/pair), budget obviously was NOT a factor. They *selected* a dome. They tested all available materials and designs during development, but chose a silk dome. That’s a clue.

    3) Tekton makes good speakers using mostly SBA drivers.

    4) SBA drivers have seen wide use across several Revel upper tier product lines, in addition to Gamut Audio, Salk, and many other companies. SBA was founded by the two former lead design engineers at ScanSpeak. The very same engineers that masterminded the entire ScanSpeak Revelator driver series. So, though manufactured in Indonesia in a fully ISO certified facility, they are world-class drivers that compete far above their actual price brackets. Extensive testing by Vance Dickason at VoiceCoil has proved this many times over. His detailed measurement data would be a good read for you.

    5) The A series does NOT use a ribbon.
    Last edited by BufordTJustice; 12-31-2020, 03:44 PM.

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  • Chane M&C
    replied
    Originally posted by GUTB1 View Post
    Well, you're right of course. I do find it silly that speakers of Wilson's price don't use ribbons, and in fact appear to use off-the-shelf drivers. Tekton being budget speakers I can understand. I guess that also answers the question: I can't expect high-end parts in a budget speaker, which the L still is -- on the higher end of budget DIY-type speakers, but still. I supposed the use of ribbons in the A series set an unrealistic precedent when you try getting into higher performance while controlling costs.
    Good points, GUTB1, and they'll raise a little more perspective on choices and results.

    Not to be contrary, but ribbons simply aren't superior as an absolute quality. They are physical devices with pros and cons and the cons are just as significant as the pros are. Even in a no-holds-barred speaker design I can't say I'd default to a ribbon just because that's what its operating principle is. They market well but they're not magic. They're a Wankel engine to the conventional reciprocating type: Excellent performance potential with as many negative considerations as benefits.

    The L models, near as I can tell, are in the upper technical reaches of fairly externally conventional, "living room" speakers. They work well because they use bona fide performance drivers and highly developed design and filter architectures to give them that get-out-of-the-way sound we tend to prioritize here. To do that they have always had a specific design goal and that goal isn't served by ribbons. BTJ has the correct perspective - you have to use a ribbon deliberately and carefully. The design calls out the speaker's typical use as well as its driver map. I think the L's are very good but I can't say they'd be improved as much as they'd suffer with a ribbon tweeter instead of the 29mm ringdome.

    The A series actually uses a planar magnetic, not a ribbon. They're both thin film drivers but the planar magnetic has much higher dynamic reserve - exceeding the usual consumer-grade 25-28mm dome in our experience - but it's not a loose accordion pure ribbon. The ribbon is a more fragile device and as such the planar has far more leeway while also costing much less.

    It's the speaker's internal design that determines its central audible personality and no tweeter type will deliver, in our experience, complete primacy in that design. The rugged planar in the A models goes well with the SplitGap midwoofers to allow the whole speaker a dynamic envelope we think is well beyond the typical budget speaker. The L models bump up to a larger 6.5" driver but don't necessarily deliver more acoustical power. They bring the refinement of the improved drivers with the design goals the acoustically larger - but not more powerful - ringdome adds.

    Eventually we'll probably get into pure ribbons, but here again the design types and the tech have to compliment one another. This class of speaker still won't do anything magical - ribbons are just tweeters, after all - but we may eke out a touch more air and sparkle from them.

    I hope this helps. Appreciate your hanging in there for the in depth conversation.

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  • GUTB1
    replied
    Originally posted by 1st Time Caller View Post

    Why Do you complain to Wilson Audio or totem or Tekton that they are not using ribbons. I would hate to opine on speakers until I actually listen to them.
    Well, you're right of course. I do find it silly that speakers of Wilson's price don't use ribbons, and in fact appear to use off-the-shelf drivers. Tekton being budget speakers I can understand. I guess that also answers the question: I can't expect high-end parts in a budget speaker, which the L still is -- on the higher end of budget DIY-type speakers, but still. I supposed the use of ribbons in the A series set an unrealistic precedent when you try getting into higher performance while controlling costs.

    Leave a comment:


  • BufordTJustice
    replied
    Originally posted by GUTB1 View Post
    Very disappointed to learn that the L series doesn't use ribbons. I wasn't following the development but since I learned about them being in the works a few years ago I was a little excited to see what was going to come out. Oh well!
    You shouldn’t be disappointed. Current ribbons are unsuitable for use in a two way loudspeaker. Period. They don’t play low enough and their distortion under 3k is absurd even at nearly-background levels of playback. You can’t cross them under 3.5khz without accepting some serious, inherent performance flaws. And if you do source a true ribbon diaphragm that is large enough to accommodate a sub 3khz crossover point without literally falling apart, then those LITERALLY can’t even reach 20khz at -3dB. Might as well use a horn and compression driver at that point (where you can throw away 10-30dB of sensitivity in your contour shaping and in the passband)

    But, bottom line, you can’t have an informed opinion on a speaker until you’ve heard it. I say that as a full voting AES member. It’s just not possible.

    If you hear an L Series model and can point to some aspect of performance that it lacks and a ribbon doesn’t, then you’re entitled to that.

    I actually heard a pair of real ribbon small two ways at Gig Harbor Audio (they make then there) while demoing the L’s with the tube amp that I ended up buying and the L’s gave up nothing to them on the top end. Nothing.

    EDIT: These were the speakers. GHA Speedsters.

    https://www.gigharboraudio.com/gha-s...carmody-design
    Last edited by BufordTJustice; 12-31-2020, 12:44 PM.

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  • 1st Time Caller
    replied
    Originally posted by GUTB1 View Post
    Very disappointed to learn that the L series doesn't use ribbons. I wasn't following the development but since I learned about them being in the works a few years ago I was a little excited to see what was going to come out. Oh well!
    Why Do you complain to Wilson Audio or totem or Tekton that they are not using ribbons. I would hate to opine on speakers until I actually listen to them.

    Leave a comment:


  • GUTB1
    replied
    Very disappointed to learn that the L series doesn't use ribbons. I wasn't following the development but since I learned about them being in the works a few years ago I was a little excited to see what was going to come out. Oh well!

    Leave a comment:


  • Chane M&C
    replied
    Originally posted by kabin View Post
    Thanks guys for providing great info. I figured lower crossovers were part of the answers for the L's. I thought the 700 series crossover was higher than the L's.

    The 752 is lower than the L3c, although not enormously. Both get their points more because of on-axis or design center targets than the MTM issue, such as it may be, but as it turns out, both are low enough to make the feared lobing thing a secondary or even tertiary problem. I have consistently found that the MTM thing, like a few other diehard considerations, is much more theory and much less real-life, in-room audibility. It goes back to the center-to-center being reasonable and the design type minimizing the second of the two considerations.

    Admittedly not the same thing as 2 drivers but I recall in the digital domain, FFT windowing/filter type tradeoffs between mainbeam widths and sidelobe peaks. Is the goal to push those sidelobes out beyond or at least at the edge of listening positions or does fatter mainbeams disrupt imaging?
    If by digital you mean brickwall filters, then only the second consideration above matters (although with reasonable centers and low enough transfer function frequencies, it's still minimized to the point of irrelevance.) Regardless, the goal of a good MTM design should be to fatten the mainbeams and overlap them well enough to deliver, in the first consideration I mentioned above, a theoretical few dB of deviation. In other words, flip the two virtual speakers, sharing the single treble section, such that the opposing nulls and beams cancel one another as well as possible.

    Design not having the ability to get to theoretical goals, the practical option is to blend as many virtues with as many mitigated problems as you can, so that the whole does the sorts of things BJT reports hearing, while not having an issue somewhere else to ruin them. The 752 uses a design type that relies on the horn's aspects and the L3c uses a similar one that uses others, while the L7 is tightly enough spaced that the issue more or less disappears. Or, hook 'em up and see what they sound like making real sounds and if they please, mission accomplished.

    Granted, what they sound like is relative. I like stuff that appeals to the MLP and the hours of relaxation a system like BJT's gives, rather than the more acrobatic things like seeing what a speaker does at severe angles. Although I think he once told me that the ringdome-tweetered L3c does things at extreme angles the horn 752 can't quite get to. Horses for courses.

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  • kabin
    replied
    Thanks guys for providing great info. I figured lower crossovers were part of the answers for the L's. I thought the 700 series crossover was higher than the L's.

    Admittedly not the same thing as 2 drivers but I recall in the digital domain, FFT windowing/filter type tradeoffs between mainbeam widths and sidelobe peaks. Is the goal to push those sidelobes out beyond or at least at the edge of listening positions or does fatter mainbeams disrupt imaging?

    Looking forward to the next production phase rollout of the 740s.
    Last edited by kabin; 12-28-2020, 01:48 PM.

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  • Chane M&C
    replied
    Originally posted by kabin View Post
    I can't tell if it's an optical illusion but are the L3C woofers spaced slightly more distant in proportion to the A2.4's size? Heck looking at my 752 woofers they appear slightly wider in proportion to my A2.4's. I can only imagine there's no shortage of parameters to consider for optimal gain/loss
    Very true - there's a lot to optimize.

    Originally posted by kabin View Post
    ...but some HT/audiophile types say there's an increased risk of off-horizontal lobing as the woofers are more widely separated in MTM configurations.
    MTM's work along these lines (from a post I made a week or so ago elsewhere):

    First, two drivers reproducing the same content from two slightly different distances to the ear creates cancellations that vary as functions of wavelength (frequency) and driver spacing where the two drivers are operating high enough to create distinct multiple sources. At low frequencies they operate in tandem as far as this directivity goes - the wavelengths are too long to make this distinction.

    With a sufficiently low crossover vs driver spacing this cancellation is mitigated or even eliminated from issue.

    Second, since all multiway speakers produce a null on the long axis at crossover at some point(s) in the forward polar pattern, adding a second lower frequency driver to mirror the first overlaps a second null at the opposite angle from the array center. Adjusting these is an option and if done with a goal, can improve the pattern. Extreme cases built just for the purpose reduce it to almost nothing, the original MTM aim.

    The L6 and L7 use both a low crossover to the big, capable 29mm ringdome - its size is one reason we chose it - and the tight driver spacing solves the rest. Our usual crossover work gives the array good behaviors in the other domains and the whole effect is that the speakers acoustically disappear quite nicely...


    Originally posted by kabin View Post
    I would guess a center speaker would exhibit worst case lobing but If so I haven't sensed it on my 752.
    ...PS: The 752's big, wide-open acoustical image suggests that even a big MTM speaker can be optimized to work surprisingly well.

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  • BufordTJustice
    replied
    Originally posted by kabin View Post
    Nice review! Sounds like another wonderful set of speakers from Chane.

    Comparing center speaker designs, I can't tell if it's an optical illusion but are the L3C woofers spaced slightly more distant in proportion to the A2.4's size? Heck looking at my 752 woofers they appear slightly wider in proportion to my A2.4's. I can only imagine there's no shortage of parameters to consider for optimal gain/loss but some HT/audiophile types say there's an increased risk of off-horizontal lobing as the woofers are more widely separated in MTM configurations. I would guess a center speaker would exhibit worst case lobing but If so I haven't sensed it on my 752.
    Well, all non-coincident multi-way speakers lobe. Period. No exceptions. The acoustic center-to-center spacing is based on a variety of factors, not the least of which is crossover point. The L’s cross lower than the A’s from tweeter to midwoofers. So this, alone, fully mitigates the additional spacing you see. The 752’s crossover is lower still. Both the 752 and L3c have equal or better center-to-center spacing compared to the Ascend CMT-340SE.

    As far as lobing, that’s something that nobody can explain the sound of. Because all it means is a reduction in volume for the passband of a few dB’s, at a certain location in physical space. So, 30 degrees off axis, the L3c will likely sound note V-shaped by a few dB reduction in the crossover region. Mind you, this same sound signature is intentionally tuned into many center and L/R speakers even when they are 3-ways. Lol. So it’s not an awful thing. I can think of an Emotiva 3-way center that is tuned to be V-shaped with boosted lower and highs compared to the mids on axis. Owners seem to like them very much. So it’s a straw man.

    In vertical orientation, the lobes are aimed at the floor and ceiling. Even better.

    The fact that you are markedly insensitive to this reduction of a few dB’s in the crossover region, 30 degrees off axis, proves my point. It’s a non issue that remains nearly exclusively academic in quality designs. Chane being among those quality designs.

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