High Efficiency Tweeter Suggestion Please

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High Efficiency Tweeter Suggestion Please

Postby LinuxGuru » Sat Nov 10, 2012 7:25 pm

Hi !

My friend acquired a pair of Technics SB G710 speakers with burned tweeters. Repair is not possible - voice coil burned during heavy overdrive and melted plastic surroundings.
I have a pair of SB G710 and SB G910, the latter need repair of horn.

Need to say, I love my G710, they have excellent sound reproduction, high sensitivity, thunderous bass, and wide angle dispersion pattern (there is no perception like sound flows from one radiating spot). In Russian jargon it is often referred as holographic sound.

Short technical specification:
SB G710 (woofer 35 cm or 13 3/4"), 4way, 8 Ohm, 97dB/W/m, crossover frequencies 350Hz, 3.5Hz, 10kHz, max input 200W
SB G910 (woofer 41 cm or 16 1/2"), 4way, 8 Ohm, 99dB/W/m, crossover frequencies 350Hz, 3.5Hz, 10kHz, max input 300W

Woofer and mid-range are classic construction. High frequency part is somewhat odd. 3.5-10 kHz handled by dome tweeter with waveguide, equipped with very short exponential horn and diffuser (acoustic lens). Super-tweeter(s) (1 in G710 and 2 in G910) handles signal over 10 kHz, and is made of ceramic and mylar film.

Since 2 pairs of speakers need repair, 1 complete replacement, another partial, I'm considering several options:
1) Replace burned tweeters with dome ones and attach them to horn and diffuser.
2) Replace tweeters and ceramic/mylar super-tweeters with ribbon drivers.
3) Replace tweeters and ceramic/mylar super-tweeters with dome driver and waveguide (in order to create wide angle dispersion pattern).

Digging among many options instantly presented a challenge.
1) Most tweeters have lower frequency 4 - 5 KHz, instead of 3.5 kHz required. For example, Monacor HT-958PA/SW, which ideally suits in terms of power/sensitivity have recommended cross-over frequency 5 kHz.
2) Tweeters with sensitivity 97 - 99 dB/W/m are relatively scarce compared to more conventional 90 - 91 dB/W/m variants.

I can saw off parts of front panels to accommodate new drivers, and make new decorative frames. Price is not an issue in reasonable degree (150 Euro is OK, 500 is not).

So, taking into account all this matter, I'm very welcome for any advice.
Thanks in advance.



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Postby Geek » Sat Nov 10, 2012 9:19 pm

Unless you want to keep it stock, I'd say go for a ribbon.

Efficiency with tweeters isn't a problem anymore.... most designs have to have the tweets padded, as they're 102-104dB along with 85dB woofers.

If you want stock, you'll likely need a matching set of speakers to rob the tweeters from, unless you want to machine driver adapters and shop Parts Express.

I see those speakers now and then in the local thrift store with a boot print on a collapsed woofer or really bad foam rot. I'll check the tweeters if I run across them again.

-= Gregg =-
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Postby DeathRex » Sat Nov 10, 2012 9:38 pm

Man do those look like my Sansui SP-Z99s.
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