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zog

active 2 way speaker using FaitalPro HF144 and Lorantz C390X B1 continued...

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Yes, good idea re protection. Always keep a cap on a compression driver, even after DSP is sorted and you have finalized the system. If you want to be oh-so-clever, size the cap for measured HP at your intended crossover point, then add the rest of the HP slope with DSP. Or, if you want maximum flexibility for playing with DSP, use an oversized cap and do all the crossover HP with DSP.

 

I've gone for oversized cap so I've got full flexibility with the miniDSP.  Except for getting better resistors and capacitors for the HF protection, and gathering all the parts (bass reflex ports from Germany, binding posts from LSK, etc) I haven't done much over winter, hopefully the warmer weather will be more amenable to building the enclosures outside.

As I've already got adequate but ugly enclosures for the LF drivers the system is functional, so I've been taking my time. The loungeroom does look like it's got a pub PA in it now though.

 

As I documented with maybe too much info in http://www.stereo.net.au/forums/index.php?/topic/54175-capacitor-recommendtions/#entry929112 the capacitor thread I'm now using "82uF" protection caps that actually measure about 76uF. I was messing around with piggyback capacitors to identically match the values, but after working out the miniscule difference in the transfer function didn't bother.

 

 

post-113607-0-65358500-1378955803_thumb.

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Nice cap, well done.

 

I can see from your plots that the horns roll off well before the cap -- so I fully agree with your approach. I'm guessing that F3 (cap, electrical) will be about 260 Hz.

 

I do like projects like this! Keep us posted, cheers.

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OK, it's been a long time since an update, but I've finally got around to ordering some pre-cut pine plywood for making better cabinets for the Lorantz woofers.

 

133L (75cm high 60cm wide 40cm deep) which according to WinISD I can tune to approx 33Hz with my PVC port extenders, or approx 37Hz just using the 20cm plastic B.R. ports as is.

 

I haven't clamped and glued yet, just a done quick sanity check that all the bits fit together:

 

unglued-lorantz-cab-test.jpg

 

I've also been dabbling with different amplifiers to drive the HF portion of this system for amusement (SET valve amps, JLH 1969 class A, even $6 chipamps), but so far my TA3020 Tripath amp seems best for the Lorantz woofers.

Edited by zog

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nice cabinet :)

woofers like power, i would suggest an amp no less than 150w.

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Looking good zog!

 

 

nice cabinet :)

woofers like power, i would suggest an amp no less than 150w.

 

isn't this a 15in woofer with reasonably high sensitivity? And active so it's not going to have a bizarre impedance curve either .... 

Edited by hochopeper

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Looking good zog!

isn't this a 15in woofer with reasonably high sensitivity? And active so it's not going to have a bizarre impedance curve either ....

you prob right after i checked the specs. but bass always preferred more power especially if no hpf applied which i assume in zog's case now.

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nice cabinet :)

woofers like power, i would suggest an amp no less than 150w.

 

I'm probably close enough to do for now - given it's a DIY job it's a bit hard for me to be precise, but I'm probably in the 110W  range - using a 500VA +-35V transformer.. which from memory gives it a +/-50VDC supply.. which seems to be about 110W into 8 ohms - and yes the Lorantz is 99dB sensitive.

Edited by zog

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im just wondering, how does this one sounds compared to the passive econowaves?

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With that sensitivity I think gain is probably more important spec than power ...

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In the suggested box on the datasheet  (110L vented 43hz) ...  Xmax is exceeded with 10w  (105dB@1m) ...  Xmech (estimated) is exceeded at 100w (115dB @ 1m)

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