|SP38/13 and Vifa PL18/XT
built by Yavor, 31 Dec '08
Happy New Year!
Mu name is Yavor and I'm a big fan of your work, I've
built two of your designs, THE sp38/13 and the Vifa
PL18/XT. Both sets sounds incredible. I'm extremely happy
with the results, thanks to you. I built both designs
exactly to your specs. The X-over and the cabinets with
the exception of the SP38/13 I made the front, rear and
top panels out of double 18 mm Baltic birch.
I have a question about the SP38. The amplifier I'm using
is the Phase Linear 700B, big solid power I am sure you
are familiar with the 350W a side amp. I would like to
get a little more power handling and possibly a little
more lower bass. The question to you is this: Can I add a
second Revelator to this system, let's say place the
driver down low, just above the first shelf of the
cabinet and let's say 6.5 mH first order separate
crossover like a 3½-way set-up.
Thanks again and best regards, Yavor.
Thanks for you response and for the nice pics. Looks
great with the solid fillets.
Making the SP38 into a kind of Ekta "G/38" is a
bit tricky as we usually in a 3½-way set-up will take
the major advantage of getting an overall higher system
sensitivity from having the lower bass driver helping the
upper bass driver in lower midrange, virtually
eliminating the need for baffle step loss compensation.
Current system sensitivity is around 86 dB and in a
3½-way we might easily tune the whole system around
90-91 dB like the Ekta Grande! However, this takes a
complet redesign of the crossover and although easy to
simulate, it takes careful fine-tuning by hand to get
3rd-4th order filters in place
Just adding a second bass driver to the exsisting system
will maintain current sensitivity and most likely make
the whole system too bass heavy, in particular from a 1st
order filter. Next: Adding a second driver will require
~twice the cabinet volume, so new cabs required.
Best regards, Troels.