|
Prodotti, prezzi, dimensioni, possono subire variazioni senza preavviso, chiedere la conferma prima dell'ordine. Prices, products, dimension, could be changed, Ask before order. Prezzi e prodotti aggiornati sul nuovo sito Audiokit e-Shop cliccando qui ! Update prices & products on new e-Shop Audiokit website click Here
|
|
By Lynn Olson
Since "keep it simple" was uppermost in my mind
at the beginning of this project, I picked drivers that were up-to-date, easy to
work with, and had first-class subjective qualities without requiring tricky
equalization circuits in the crossover. (Not many drivers qualify!) The Vifa 5.5" P13WH-00-08 midbass is refreshingly
free of the muddled and confused sound of typical 7" and 8"
polypropylene drivers. This is almost certainly due to the small size of the
cone, which makes it more rigid, as well as careful Vifa engineering of the
vented pole-piece assembly. The frequency response of this driver is also pretty
remarkable, with a ruler-flat midband gently descending to a smooth 12 dB/Octave
rolloff beginning at 5kHz. That means the crossover can be simple, and won't
require midband equalization. The flatness of the 5.5" Vifa driver is more unusual
than it first appears. Since the ear is so sensitive to spectral imbalances in
the midrange, most high-fidelity speakers have traditionally used modest
equalization in the crossover to straighten out the crucial midrange. It is only
in the last few years that we have started to see high-performance drivers that
don't require any equalization, and the Vifa 5.5" midbass is an excellent
example. (The only other one I can even think of is the Focal 6V415, and even
that one has a small bump at 4.5kHz). I first heard the 5.5" Vifa in the Lineaum LFX, and
was impressed with the wonderfully transparent midrange. I was not so impressed
with the thin bass. I figured if this driver had any future as a good midbass
unit, a pair of them driving a 6 foot transmission-line would bring it out.
Doubling up would gain 6dB of efficiency and headroom, and the transmission-line
would extend the bass down to the F3 of the driver - 60Hz. By contrast, a vented
box with conventional Theile/Small QB3 tuning begins a 24dB/octave rolloff at
80Hz. The two orthodox approaches to get deeper, more powerful
bass would be:
High-end speakers in the middle price points ($1000 to
$5000) usually compromise the mids in favor of getting more of that intense bass
that many audiophiles want. Increasing the size of the midbass driver reduces
the midrange quality in the case of the Vifa (and many other drivers). The
6.5" and 8" Vifa drivers need modest midrange equalization, and after
you go to all that extra trouble and expense in the crossover, they still
don't sound as good as their little brother (EQ is not a substitute for
quality). Going to a 3-way system by adding another passive
crossover at 200 to 300Hz is just asking for trouble in terms of large,
expensive, and sonically intrusive capacitors and iron-core inductors. Assuming
you spent a small fortune on crossover parts, there's still the problem of
having the crossover fall in the range where the ear is most sensitive to phase
distortion (100 to 800Hz). And for what? Most 10, 12, or 15-inch poly-cone
woofers don't have such great bass anyway. It's loud and deep all right, but
they can't keep up with good mids and tweeters. That's why most 3-way systems
avoid using the best midranges and tweeters - although top-quality mids and
tweeters don't add much to the price, they expose the poor quality of the
generic poly-cone woofer. Good woofers quickly run into serious money, and it
takes bi-amping to really do them justice. The design tradeoffs in the Ariel are very high quality
midrange and treble, focus and immediacy across the spectrum, and good
efficiency - at the expense of deep and powerful bass. I tell most folks to go
ahead and build the Ariel, and see if they want more bass after they live with
it for a few months (it's a bit like acclimating to Quad ESL's or Lowthers). If
you'd like a bit more extension, don't rush out and buy just any commercial
subwoofer; most of them can't keep up with speed and resolution of the Ariels.
(With the notable exception of the REL subwoofers, which work just fine ... I
own a REL Strata II.) Take a look at the Good Bass section for more info
on which woofers (not subwoofers!) are a good match for the Ariel and ME2's. Returning to the midrange, I cannot recommend any other midbass driver as a substitute. If you want to use any other drivers you are completely on your own. There are a handful of top-rank tweeters to choose from,
unlike good mids, which are scarce. This is the result of many advances in
materials sciences, acoustic holography, and computer modeling in the last
decade. Soft domes in particular have made great strides, and are head and
shoulders above the popular soft-domes of the Seventies. The best soft-domes
(Scan-Speak D2905/9500 and D2905/9700) now surpass the best metal-domes. The issue of subjective coloration goes a bit deeper than
flat response and good MLSSA waterfall plots. The best tweeters meet all the
technical criteria very well; what remains are the subjective differences. This
is where I part company with the detail-at-all-costs brigade, and go for the one
that sounds the most true-to-life. I am not a fan of the "analytical"
cookie-cutter sound so popular in the high-end magazines. My criteria are much
simpler: does it sound like real people singing in my living room? Does the
clarinet sound like a real clarinet? Is it real; does it live and breathe? The Scan-Speak D2905 family of tweeters communicate this subtle essence in the most natural way I've heard so far. Here are my personal impressions of the top three models:
In purely objective terms, the Vifa P13WH-00-08 and Scan-Speak D2905/9500 are the flattest, most neutral drivers in the world; the group-delay vs. frequency and MLSSA waterfall results are truly exceptional. Not to mention they sound great as well! Don't take my word for it - other builders of the Ariels
have called me up long-distance and told me they were fooled into thinking a
party was having an impromptu sing-in in their living-room. One fellow even
thought one of his next-door neighbors was humming along with the music - turned
out the humming was on the recording, and he had never heard it before! With a
moderate-power vacuum-tube amplifier, voices, piano, and clarinet have an
"in-the-room" presence that is relaxed and natural ... quite different
than the "high-end" sound you hear at the shows.
Prezzi e prodotti aggiornati sul nuovo sito Audiokit e-Shop cliccando qui ! Update prices & products on new e-Shop Audiokit website click Here
mercoledì 02 luglio 2014 |
|
Copyright © 1996 - 2009 Audiokit All Right reserved, name and brands are of respective owners. |