Newsgroup: it.hobby.hi-fi
Titolo: Autocostruzione:Tweeter equivalenti a livello crossover

    I don't normally make "drop-in" driver replacement recommendations, 
because it's important to measure the response and impedance of a 
driver, before you can determine how well it will work with a particular 
crossover.  Nevertheless, I received numerous requests for an 
alternative to the North Creek D25 in the PeeCreek design.  Those of you 
living outside the U.S. know that once shipping charges, duties, etc. 
are added to the cost, that little $18 tweeter is no longer 
cost-effective when compared to the many available tweeters to those 
living across the globe.  Accordingly, I tested various units to find 
those which can be used in the PeeCreek design without changes to the 
enclosure or crossover.
    The first "trick" is to find those tweeters with faceplate sizes 
which are identical to the North Creek.  Second is to measure the 
frequency response and impedance of each, then evaluate them in Calsod, 
to model the predicted rolloff rate and total system response.  Below 
are the results for the Morel MDT-20 (which, I'm told, is available 
world-wide).
 
    As you can see, the predicted response for the MDT-20 as  "drop-in" 
replacement for the D25 is quite good (although you need to connect with 
with normal (+) polarity).  The next step was to connect it to the 
PeeCreek crossover and measure the overall response.  That's shown below 
and also appears to be quite good.
    The proof, however, is in the way the driver sounds.  Overall, the 
Peerless 850122 + MDT-20, i.e., MorePee, combo sounds different from the 
D25, not better or worse, but different and certainly acceptable.  The 
MDT-20 is a bit more refined than the D25 and sounds a bit smoother.  
The D25 appears to provide a bit more resolution.  Either way, they both 
make for a very good system. 
    Ok, so what about those of you who want a bit more performance?  The 
next, genuine, step-up in performance for a "drop-in" replacement is the 
Usher 9950 (also connected with normal polarity).  It's an excellent 
tweeter for $50 and, although it produces a total system frequency 
response that's not much different than the Morepee combo, the sound is 
noticeably cleaner, smoother, more resolved, and more life-like.  You 
wouldn't even know it's the same system as either the Morepee or 
PeeCreek, if you drop-in the Usher 9950.  I highly recommend the use of 
this tweeter in place of the either the MDT-20 or NCMS D25.  After a 
year of owning the PeeCreek, Morepee, or any other design in the price 
range, you would gladly spend an extra $50 if it promised a significant 
performance increase (hey! -- look what those poor saps who built the 
"DIY" kit at Audioreview have been doing -- changing crossovers, 
monkeying with resistors, etc.!  If you don't want to go through all 
that hassle, just drop the 9950 into the PeeCreek design and sit around 
listening to you favorite music and not worry about messing with 
anything!)
    Below is the total system response for the 850122 + Usher 9950 combo 
in the PeeCreek enclosure with the PeeCreek crossover.  Give it a try!  
In the U.S., the Usher 9950 is available through Euphase Audio and will 
soon be sold through Zalytron also.  There's another site in the 
northwest that sells them, but I don't have their name handy.
-- 
L'eventuale link qui sopra ti porta alla specifica risposta che cerchi e che preferisco non darti qui .
Ciao
berry
be...@soundberry.com
scrivetemi per risposte personali.

berry ha scritto:
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TRADUZIONE:
COMPRATE LE USHER E IL VOSTRO CAMINO SARA' PERFETTO!!
MAI PIU' FUMO!!!!!!!!!! AVRETE CON IL LEGNO DELLE USHER UN FUOCO
ECCEZIONALE E I VOSTRI AMICI,ACOLTANTO UN PO' DI MUSICA CON LE OTTIME
SONUS FABER CREMONA, SARANNO FELICI.
-- 
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On Wed, 18 Jun 2003 17:37:38 +0200, 
mim...@tiscali.it
 (domenico)
wrote:
Posso pregarti di quotare.
Grazie

SONUS FABER CREMONA, SARANNO FELICI.
Si vede che a te interessa piu' sparlare che dare corrette informazioni.
Le ottime cremona costano due-tre volte tanto e non suonano 
assolutamente meglio.
Informazioni avute da chi le ha ed ha scoltato anche le Usher.
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IT.hobby.hi-fi
^^
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