- "dedicated follower of
or just another tweeters distortion test
By request here are a few
distortion tests of some of the tweeters I have
on the shelf. A guy from Finland asked if I'd
Krutke's ribbon tests and would I please
comment on this. Yes, I often visit ZaphAudio for
Krutke's tests of drivers; very useful.
If ribbons are used properly, i.e. high slope
filters and not taken too low, I think they may
deliver some excellent highs. As can be seen
below, distortion levels go low from simple
filtering; so low, I think it's irrelevant. My
worst experience with ribbon tweeters is the Red
Rose Music Rosebud mini-monitor. From
the German Image HiFi magazine test it can be
seen that this speaker has a 2nd order filter to
the Aurum Cantus 130F1 midbass and - hold on -
first order filter to the AC G2-variant ribbon.
This speaker was almost ripping off my ears. Hard
to believe this was designed by Mr. Levinson.
Anyway, it's always interesting if measurements
can be be reproduced over time and location and
with different instrumentation, so here we go.
Red = SPL/2.8V/0.25 m (for most
tweeters this will produce 89-92 dB SPL at 1
meter. Actual level is important here).
Blue = 2nd
Green = 3rd
yellow = 4th
purple = 5th
Distortion lines raised 15 dB.
All tweeters having 33 uF in series, the ribbons
must have, thus all others had the same
regardless of impedance.
All tweeters were flush-mounted.
All graphs having 1/12 octave smoothing.
In conclusion I have to say that
there is no correllation between distortion
levels and which tweeters I like and which I
dislike. So don't discard a certain tweeter based
solely on distortion levels; it may very much
depend on how it is used and which middriver or
midbass it has to mate.
Aurum Cantus G2Si. Yes,
high 3rd harm. dist. below 4 kHz. 2nd harm. dist.
rising towards 10 kHz. This looks a bit strange,
so what about the other sample?
Aurum Cantus G2Si, sample
#2. Yes, 2nd harm. dist. at 10 kHz is the same as
for sample #1.
Fountek JP2 ribbon
tweeter. This is large ribbon and it seems like
3rd harm. dist. pattern is repeating itself. No
rise in 2nd harm. dist. towards 10 kHz as seen
for the AC ribbons.
Fountek JP3, my favorite
ribbon tweeter. Same picture again. Quite low 2nd
towards 10 kHz. Is this why I favour the JP3 over
Fountek JP3. Here with
3.3 uF in series. Let's take a look at the 3 kHz
point. Here we have 3rd harm. dist. more than 40
dB down (remember dist. lines are raised 15 dB).
-40 dB should account for 1% distortion, so
really not too bad from a simple 1st order
Fountek JP3 again, here
with 3.3 uF/0.18 mH (simple 2nd order filter). I
consider these distortion levels for
Fountek NeoCD3. Very much
the same picture as for the "naked" alu
ribbon. I had expected these laminated ribbons to
perform differently. Looks very much like the
SEAS 27TDC. Not bad at
SEAS 27TFFC. 3rd harmonic
well in line with 27TDC, however some 2nd
harmonic distortion at 6-10 kHz. Is this why I
like this tweeter so much? I really favour the
27TFFC over the 27TDC....
Vifa DX25TG. A noticeable
rise in 2nd harm. at 6-7 kHz. Otherwise excellent
The Vifa XT25TG really
has low distortion levels. Is this why some
people think this tweeter is boring? I like it a
lot. Peculiar dip in 2nd harm. at 7.3 kHz.
My farourite large dome,
the SS 3806/8200. Used in the SP38. Extremely low
3rd harm. This "tweeter" can be used
Another of my favourites,
the SS 9800. I don't think it comes much better
Not my favourite tweeter,
the SS 8513, used in the 2.5 clone. I wouldn't
take this tweeter below 3 kHz and I'd use a 3rd
order filter. I think he SS 18W/8535 and the SS
8513 is an unfortunate combination. The 8535
cannot play upper mid/lower treble and the 8513
shouldn't be taken too low. Bad mix Mr. Tyler.
Morel MDT30, a tweeter I
love to hate. I had a friend coming in with a
speakers fitted with this tweeter and we could
never make it work, so he left it behind in
favour of the Vifa XT25TG. I really don't know
why it was doing so bad. Apparently distortion wasn't
I like this Neo3PDR
planar a lot and it was used in the Point75
construction and I have plans to use it some
more. Here with the crummy plastic rear chamber
as supplied. Still performing well.
Neo3PDR planar with an
open back (dipole) as in the Point75. SPL is
lowered slightly from removing the rear chamber,
so is 2nd and 3rd harm. dist.
JBL LE20 tweeter. This
tweeter has some significant higher distortion
levels compared to most modern tweeters. 2nd harm
at 5-8 kHz is really high.
JBL LE26. This tweeter
should probably not be used below 3 kHz. 2nd
harm. fairly low above 3 kHz. Some 3rd harm. at
Wharfedale Super 3. This
is really vintage stuff and it's doing much
better than expected. Some 2nd towards 10 kHz,
but 3rd is fairly low and all harm. goes flat
down to 1 kHz.
No rear chamber used during measurements, so this
Peerless 62CT pp-cone.
Not really vintage, but I like them so much I
wanted to see how the would perform here. Not bad