Martin Poulin
The N28BER-G. Ultra High Purity (99.4%) Beryllium Dome is shown here.
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This tweeter is the most expensive of the three, by a good margin, as Beryllium tweeters cost more to manufacture.
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My measurements are a bit off from the factory specs, but overall, the unit sounds fine. I like the Ceramic version better myself.
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I remember the owner of TLab’s once told me in an email, that he only offered the Beryllium tweeter because the market requested it, as it’s not his favorite tweeter either.
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Stock Frequency curve below.
Stock Frequency curve below.
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My 96 kHz sampling measurement:
And yet again, the manufacturer omits the 43.0 kHz break-up in their graph and stops the measurement at a very convenient 20 kHz.
I'm not sure why there’s a null at 25 kHz but it’s there anyway.
Measured at 3" at 95 dB.
3 kHz to 20 kHz is optimal for this tweeter
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Disregard the harder break-up peak at ~43 kHz, as this tweeter sounds good.
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Remember that all dome tweeters do have a break-up of some sort anyway. The fact that certain manufacturers don’t show it to you doesn't mean it doesn’t exist.
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The subjective sound is very "studio like". Very detailed but lacking attack, especially when directly compared to my ceramic dome version. You’d would never know this, if you didn't have the chance to compare them side by side.
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It would match very well with some 3" dome (ATC or VOLT) mid-range units in a 3-way design as small dome mid-range excel in resolution rendering.
​Ultimate resolution is great, but it’s hard to integrate it with a mid-range, as most won't keep up. Matching always matters more than individual speaker selection. The Beryllium is certainly more sensible to such.
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Unlike the other TLab tweeters, this one is more efficient at 95.5dB.
Bonus:
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I anticipated the beryllium tweeter would rouse the most interest of the three on this site, so I added a comparative summary.
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Magnesium dome is Yellow ($125 each)
Ceramic dome is Green ($250 each)
Beryllium dome is Purple ($500 each)