Jordan Drivers

Archived from groups: rec.audio.high-end (More info?)

Philip Meech wrote:

> Does anyone here have any experience building speakers with Jordan full
> range foil drivers?

I do have experience with one set of JX92S on a sealed 7 liter
enclosure. I am not a professional in the terminology and listening
analysis, but will attempt to give you a glimpse of how I feel with them.

Generally speaking, you want to have either a BSC or series notch filter
to compensate the baffle step and rising frequency response on upper
range (and IMO to be able to enjoy the speaker sound overall, the sound
is somewhat "dull" without any compensation. However, the 15 degree
off-axis response (as manufacturer states in the website) without any
compensation is good for most people, like me for the first 3 months of
listening

A word about how the response looks. The bass response on a 7L sealed
enclosure is 0dB at 100Hz, -5dB at 60Hz and -10dB at 45Hz (measured with
near-field MLS in generic room circumstances). I have not much to say
about far-field response as I just recognized my notch filter being
designed for somewhat different enclosure, and the response does not
"look good" (-2dB at 4kHz, 0dB at 1kHz and 7kHz), totally response stays
within +-2.5dB between 200Hz and 7000Hz. Otherwise, if someone ever
minds, it should be quite easy to get response stay within +-2db in a
critical range. I'll probably be constructing an acoustic resistance
enclosure for these drivers early fall, hoping to get rid of a
traditional "sealed cabinet tone" and getting some improvements to
off-axis response and bass range.

Speakers with these drivers will show their capabilities especially with
vocal music and good recordings. The sound stage is accurate, wide and
opens well behind speakers, giving a good transparency to listening room.

The transient response with acoustic instruments is good enough (though,
I would expect something more for strings) and recording details are
easily caught. The upper bass range would benefit from support in the
lower bass. This can be heard with instruments like double bass or
cello, which frequency range goes till area, where bass response have
already begun to attenuate (regardless of the fact that the listening
room in most situations usually compensates this area).

Some argue the treble range on JX92S. I do not particularly find
anything more in there. The response remains above 0dB from 4kHz, still
not brassy.

Drivers are easy with listening environment, given that there's enough
space between speakers and back wall, and they are located not wider
than equilateral triangle in regards to sweet spot. Also, you will like
to listen them vertically located in exact ear-level. Drivers also
require a long time to break in, say 50 hours plus.

With bad mixing, they are really brutal to records. With classical music
(like what I'm listening, mostly older than from 20th century), it's
really trivial to determine an instrument that has not been in the
original recording situation, but have been mixed into master (I've got
one cd, where whole orchestra opens to proper place, still having one
trumpet locatable in the middle of a cone, changing a cone from left to
right during recording...) However, I'm incapable of telling, whether
this particular cd sounds similar in other systems too...

--
\lapa
Lauri Palokangas

Archived from groups: rec.audio.high-end (More info?)

Philip Meech wrote:
> Are you satisfied with this driver in comparison to Vifa and Seas?
> Would you prefer a two driver setup using JX53 and a JX92S in linear
> array in a 13 litre sealed box?
> Have you had any dealings with Madisound or Parts Express?
> What did you do for a cabinet? Thanks.

Unfortunately my experience in Vifa or Seas are not in level that I
could objectively (or even semi-objectively) compare these systems, I
certainly leave this question for someone else. Neither I have dealt
with Madisound or Parts Express, I've used local dealers here in EU.

Two JX92S are certainly worth trying. However, to choose between 53 or
92 on linear array, I'd personally go for array of four JX53 with these
arguments:
1. Being just recently heard a set of them, they were more stabile in
the sound transforming from bass to treble
2. As neither 92 nor 53 are real full-range speakers, to get the lowest
octave and below, you still need a subwoofer (someone don't by I, at the
moment, do). IMO crossing subwoofer at 60 compared to 100 does no really
make any difference in this context
3. You will get 3dB more sensitivity with a set of four compared to set
of two.

On the other hand, a JX53 set that I heard were dramatically more
demanding in placement than my JX92S. I hardly found a comfortable
listening point for them during my quick listening test. The soundstage
did not open in the same way than JX92S does in every occassion (this
probably indicates either a comb filter or front baffle/edge diffraction
and will be easily eliminated just with a proper cabinet construction).

My cabinet is made of a double-22mm (7/8" ) MDF constructed with glue
only (the total thickness of each wall is then 44mm). The cabinet is
rounded over with 38mm (1.5" ) from every corner and side. The driver is
flush mounted. (See http://lapa.itgo.com for first impression,
discarding the simulated in-room response)

If you are still in a stage of choosing an element, I'd like to use the
opportunity to suggest Tangband W3-871S in a linear array. With a price
of a $10 each, you can easily afford a line array of 24 at the price of
2 pieces of JX53 or JX92S. I have heard them (and been lately living in
symbiosis with them and appropriate MLS tools), and would immediately go
for them, except that I (and especially the rest of my family) just
happen to be in love with compact-size speakers...

--
\lapa
Lauri Palokangas