Optimus Pro LX5 / Linaeum
Phil Brown
and have heard they are ripe for mods. If anyone has any info to
that extent, would you please email me with it?
Thanks,
-Phil
http://www.best.com/~duda/PBMAIN.html
Chris Christensen
I _shouldn't_ do this....
>I just bought a pair of these babies (now on sale for $100 each)
>and have heard they are ripe for mods. If anyone has any info to
>that extent, would you please email me with it?
Ripe for mods?
How do they sound _now_?
You :could: rebuild the crossover...
You :could: replace the LF driver...
You :could: also rework the cabinet...
You :could: also rewire for bi-wiring...
You :could: do all of the above suggestions and spend another $100 each and be
a happy camper! But think about it!
--
Just My opinion, worth the price paid and not a reflection of my employer.
D.R. "Chris" Christensen chr...@shasta.gvg.tek.com
Grass Valley Group Inc. 916-478-3419 Voice 916-478-3887 FAX
P.O. Box 1114 Grass Valley, California, 95945
Phil Brown
In article <45h7m5$3...@gv-gate.gvg.tek.com> Chris Christensen
wrote:
>Date: 11 Oct 1995 19:59:01 GMT
>From: chr...@shasta.gvg.tek.com (Chris Christensen)
>Newsgroups: rec.audio.tech
>Subject: Re: Optimus Pro LX5 / Linaeum
Actually, they sound quite nice, thank you very much! I'm still
breaking them in, but the sound "out of the box" was impressive.
The bass is a bit boomy, and obviously doesn't go that low (about
100Hz) since it's a 5" cone. I won't play around with them
(mod-wise) for a while, but it's nice to know what others have
done, so that when I get around to it, I know where to start.
Most of the responses I received were from rec.audio.high-end;
rec.audio.tech did not have much to say. Most suggestions were on
crossover upgrades (eg, replace the highpass cap with a better film
version, replace the lowpass inductor with an air coil, etc.). Box
dampening was also touted (putting coffee straws in the vents
seemed popular). Here is a collection of what I found, what was
posted, and what was e-mailed to me. Thanks to all who answered.
Date: Mon, 9 Oct 1995 05:12:31 -0400
From: joh...@aol.com
To: Phil...@gnn.com (Phil Brown)
Subject: Re: Modifying Optimus Pro LX5 / Linaeum
In article <45a9vm$8...@agate.berkeley.edu>
Phil...@gnn.com (Phil Brown) wrote:
>I'm looking for information on improving the crossover and
possibly
>replacing the bass driver on the Optimus Pro LX5 speaker from Rat
>Shack. Has anyone been successful in modifying this speaker? The
>pair I have has a rather flabby mid bass, with plenty of vent
noise.
I've been using modified LX5's in a sub-satelite setup for more
than
four months now and their clear, natural, and transparent sound
combined with their exceptional imaging impresses me more and
more each time I listen to them. They're definitely the best
sounding
speakers I've ever owned and I can't think of how my system could
sound much better short of spending 5 to 10 times their price.
Here's what I did to make them sound good.
First I replaced the crossover components. I didn't really change it
much, I simply got rid of that little 1mH ferrite core inductor which
was mounted on axis with the driver right behind the magnet, and
replaced it with an air-core inductor of the same value which I
mounted in the bottom of the enclosure between the vent ducts,
orthogonal to the speaker axis. Actually, I glued it onto the thin
foam pad in the bottom. Then I replaced the 6.2uF cap with 6.7uF
Chateau Roux caps. It was not my intention to change the value,
but that was the closest I could come with parts on hand and I
didn't think it would cause any problems. I mounted the new
capacitors on the inside back wall where the original capacitor
was mounted and just above. I cut some foam strips and
superglued the caps to the foam to the enclosure.
Secondly, I added foam damping to the enclosure and plugged the
ports with foam. I first removed the thin piece of foam on the one
enclosure wall and cut peices of two inch foam to line the side walls
and top with a couple of little pieces stragegically placed on the
back wall. The foam I used had an egg carton shape on one side.
I plugged the ports with foam rather than sealing them completey
because I thought they might act like aperiodic dampers for the
driver. I left the little white piece of stuffing on the back wall under
the wires to the tweeter.
Well, these speakers really sound nice, now, and they play at least
twice as loud. I think the original ferrite core inductor was saturating
at high power levels. Midrange clarity and transparency improved
tremendously. In fact, these things sound as good on vocals as
any speakers I've ever heard. Vocalists sound like they are
standing right in the room, not comming out of a box. And that
di-pole ribbon tweeter is really fast and smooth. I think it's the
major contributor to their exceptional imaging. The sound stage is
broad and deep, and the speakers essentially dissappear
completely on well recorded material. I've been an audiophile for 25
years and I can't remember when I've been more impressed with an
inexpensive speaker, or an expensive one, for that matter. But, I
better tell you how I've got them set-up.
They're mounted on tripod stands well out into a fairly large
listening room. They produce very little bass below 150 to 200Hz
so I'm using a pair of Cambridge Soundworks Ensemble bass
modules to fill in the bottom. The bass modules are on the floor
in front of each speaker with their drivers pointing up. They seem
to blend perfectly with the LX5's for a totally integrated sound.
I've also got a powered subwoofer with its crossover set at 60Hz
and I'm using an active crossover to the LX5/Ensemble system
set at 80Hz. I think it's important to get the low frequencies out
of the LX5's in order for them to sound their best.
Well, that's my setup, and I couldn't be happier with the way it
sounds. Everyone who's listened to it has also been quite
impressed. Early on, I considered replacing the midrange driver,
but after the basic modifications to the crossover and enclosure,
I'm not sure anything would be gained by doing so.
Cheers,
John Elison
Date: w
From: l...@ple.af.mil (seel)
To: Phil...@gnn.com
Subject: RS Linauem
Hello,
I saw your post to rahe and I'd like to suggest a mod to the LX-5
that I
found worked well. The mod I tried was inspired by the Stereophile
review
of this speaker. One of the writers stuffed both ports with
drinking straws.
I tried this mod with thinner coffee stirring type straws cut to
1.25 inches
lenght. I found that there was more bass control, but the sound
overall was too thinand bass and midrange.
I experimented some and found a very good balance
when the front of the straws protruded 0.5 inches from the front.
At this
point more lower midrange and bass is evident with bass control
better
maintained than for the stock configuration. With this mod I
believe the sound
is competetive with my JM Labs Micron, which is significantly more
expensive. Give this a try and let me know what you think because
I'd like to see if
someone else agrees with my assesment.
Note, based on comparing test measurements Audio and Stereophile magazines for
this speaker, there appears to be a degree of variation bass driver
characteristics from unit to unit, so you might find a different optimum point.
Stuart Lee
l...@wilma.ple.af.mil
Date: Mon, 9 Oct 1995 20:42:14 -0500
From: nbe...@uiuc.edu (Noam Ben-Ami)
To: Phil...@gnn.com
Newsgroups: rec.audio.high-end
Subject: Re: Modifying Optimus Pro LX5 / Linaeum
In rec.audio.high-end you write:
>I'm looking for information on improving the crossover and possibly
>replacing the bass driver on the Optimus Pro LX5 speaker from Rat
>Shack. Has anyone been successful in modifying this speaker? The pair
>I have has a rather flabby mid bass, with plenty of vent noise.
>Thanks in advance,
>-Phil
>http://www.best.com/~duda/PBMAIN.html
Open the box, add damping materials to the inside, replace the components
with higher quality ones of the same values. Close it up, PLUG THE PORT,
and you should have a lean, mean, music machine.
--
Noam Ben-Ami is nbe...@ux4.cso.uiuc Solar Audio High Performance Speakers.
http://www.cen.uiuc.edu/~nb10440
My credentials..............Audiophile, programmer, ticklish person, grouch.
My opinions are those of Solar Audio and came from the back of a cereal box.
Date: Tue, 10 Oct 1995 10:38:30 -0500
From: mike_...@netsolve.net (Mike Fenech)
To: Phil...@gnn.com (Phil Brown)
Subject: Re: Modifying Optimus Pro LX5 / Linaeum
In article <45a9vm$8...@agate.berkeley.edu>, Phil...@gnn.com (Phil Brown)
wrote:
> I'm looking for information on improving the crossover and possibly
> replacing the bass driver on the Optimus Pro LX5 speaker from Rat
> Shack. Has anyone been successful in modifying this speaker? The pair
> I have has a rather flabby mid bass, with plenty of vent noise.
See if this helps (long):
-------------------------
Msg#: 7490 *Audio Hardware*
11-05-94 16:32:00
From: DAVE CAIRNS
To: KINHLUAN NGUYENNGOC (Rcvd)
Subj: REPLY TO MSG# 7351 (LINAEUM OPTIMUS)
KN> I seem to recall that you tried the Optimus powered sub which is on sale
> for $299 I think...if so, how did that turn out ?
I kept it... and the LX-4's (aka the Kevlar babies.) It seems
to be a pretty good deal for the money, but I think that one of these
days I'll get into its crossover and revise a bit. I don't think it
would be able to match anything with much more bass than the LX-4 has
because its crossover rolloff is too slow. However, it can make the
LX-4 into a pretty good full range speaker system. I haven't tried my
homemade subwoofer which is quite good (and also built into an 18 cubic
foot brick enclosure in a different room!)
KN> no sign of "Brad's" LX5 yet, but upon checking the pic, it too has a
> deeply recessed woof
Funny you should mention the LX-5s :-) I needed some coax and
ended up buying a pair of the LX-5s today. They were $129.99 each on
sale. They are still breaking in, but I'm not conviced that I'll be
keeping them. Maybe.
I have absolutely no complaint with the tweeter. It is sweet,
easy, and detailed. Overall, they have an "easy-listening" tonal
balance, sort of like some of the old Polk speakers. They are MUCH less
demanding than the LX-4. The LX-4 sounds very "alive" and forward but
the LX-5 is quite "laid-back" and recessed through the midrange. They
seem to lack the dynamics and life of their less expensive siblings.
They sound almost muffled and as if the loudness control on a
receiver was on. Those are the negatives -- the positives are an almost
total lack of the "crossover region" hardness and glare that so many
speakers have, and that easy treble. The soundstaging seems to be very
good.
This is a VERY sketchy first impression. They haven't been in
the system for much more than an hour. I'll let you know more as
they break in and I play with them. They may yet find a place in my
video system
Msg#: 7527 *Audio Hardware*
11-06-94 12:08:00
From: DAVE CAIRNS
To: KINHLUAN NGUYENNGOC (Rcvd)
Subj: REPLY TO MSG# 7351 (LINAEUM OPTIMUS)
Second opinion of the Radio Shack Pro LX-5 with Linaeum dipole
tweeter.
After a little break-in and the XLO disc for an hour (we went to
breakfast) they sounded better. Pretty musical, but that bass
midrange emphasis is hard to get around.
Take the bass-midrange grill off. Oh... that's significantly
better. Still too much boombox sound. Lots of promise though. Take
off the tweeter grill. Clearer, cleaner, better treble.
Lets look inside. The binding posts are better than any I've
had on high end equipment. They are solid metal and would probably take
8 gauge wire (they swallow 12 gauge whole.) Crossover components are a
small inductor and a 6.2 mF yellow film cap. One side of the enclosure
has about .5 inch of a foam glued onto it. There are two plastic
extentions to the front firing ports which might be replaceable or
tunable. Just behind the woofer is a small amount of unglued (dacron)
batting. It is about .75 inch thick and not very dense. You can see
light through it easily.
Put it back together. Experiment with placement some. After I
bring them out from the back wall about four feet, the mid/bass "boom"
is better.
Thinking about this, Linauem probably designed some really nice
speakers for the Shack which were then compromised. Maybe the Shack's
marketing guys said, "we need more bass and a bigger sound." Maybe they
retuned the enclosure. My guess is that a little long-haired wool
behind the woofer would help both the midrange quality and the "boom."
I'll try that latter. Possibly making the ports longer (?) will lower
the tuning and remove some of the lower midrange congestion.
Lets test some of this thinking. Here's some .3 inch blue foam
that was packaging for something. You can blow through it pretty
easily. I take four pieces of about 1.5 square inches each , roll them
up and stick one in each vent. WOW! This hypothesis is going places...
Now they sound more like a speaker this size should. They don't
have as big a sound anymore, but the lower mids and bass are much more
in balance with the upper mids and treble. The "one note" quality is
much reduced . They sound good. I'll definately keep them.
Hmm... what about resistive vents like the Proacs? The
Loudspeaker Design Cookbook says that internal damping (WOOL)
should make the same kind of change but improve the midrange quality
more. Hmm...
Msg#: 7631 *Audio Hardware*
11-07-94 17:14:00
From: DAVE CAIRNS
To: DAVE CAIRNS (Rcvd)
Subj: REPLY TO MSG# 7527 (LINAEUM OPTIMUS)
I'm getting excited!
I cut 20 plastic drinking straws to 4 inch length and stuffed
five in each port of the LX-5s (just a little below flush with the
baffle.) The lower midrange / upper bass emphasis didn't go away (I
used a RS SPL meter to check) but it became smooth and subjectively
unobtrusive. They now have that emphasis that can make a little speaker
sound full and large, instead of a mid-fi boom. This made a big
improvement.
Then I tried replacing the dacron (?) pad with long-haired wool.
At first I overstuffed the enclosure and killed the life. I finally
ended with a teased wool mat about 4 by 6 inches by a little under one
inch which weighs just a bit more than the original pad. In other
words, just a little dab will do you. This change caused the
midrange to
lose some grain and once again the whole sound got silkier and
smoother.
The wool goes in easily when you remove the machine screws which
hold
the binding posts on.
I made all these changes in the correct way. I mean that I
kept
one speaker as a control while I changed the other. I then
compared the
two. My wife also compared. In each case, there was no question
that
there was a significant improvement. After making an improvement,
I
modified both speakers, compared to make sure they sounded the
same,
and reiterated the proceedure using monaural source material. The
speakers have also broken in more which probably means that I
should
wait a while and repeat all of these experiments. It is probable
that
my choice of straw length and stuffing density are not "ideal" but
they
are a real nice start. I didn't go to exhaustive length trying
differing lengths and densities.
The sound from these speakers is now much better than good.
The
midrange is still a bit recessed but very natural and easy. The overall
sound is smooth and natural. The soundstage is very large and wide (way
beyond the speaker edges) with good depth. The treble is extended,
silky, sweet, and natural. The midrange to treble transition is free of
the irritation/grain/glare that so many speakers have in that area. The
main failure of these speakers is their lower midrange - upper bass
hump. This hump may make them a difficult match with subwoofers but it
makes them nicely convincing as a stand alone product.
Without modification, these speakers are only interesting. With
a few simple and easily reversable changes, they are really special.
Don't forget to take the grills off!
Down the road: better capacitors and more refinements -- but
really, I could live with these just as they stand for a long time...
RS rates these at 89 dB sensitivity. They might be great with
single ended triodes.
Msg#: 8275 *Audio Hardware*
11-12-94 14:52:00
From: DAVE CAIRNS
To: BRAD SANDERS (Rcvd)
Subj: REPLY TO MSG# 7861 (LINAEUM OPTIMUS)
BS> So - do you like'em better than (or not as much as) the LX-4s?
Overall, MUCH better... the Lx-4s do have a special "life" to them, but
the LX_5s tweeter is one of the best I've ever heard.
BS> Do youthink, were one to "piece" these together from drivers,
> one would be better off buying the LX-4 tweeters...or the LX-5s?
> I'm thinking dipoles here, probably in a D'Appolito arrangement.
While I very much like the LX-4 tweeter, I LOVE the LX-5 tweeter,
especially when treated to a bit better mounting. It sounds better to
me than the Celestion SL700se tweeter, the Focal T-90, the Dynaudio
D-28af, and is at least on par with the Martin Logan Aerius in the
highs.
I'm not sure about the bass-mids. The little Kevlar is very
lively, the LX-5 unit is very smooth.
BTW, I see no easy way to mount the dipole tweeter in an MTM
array.
Msg#: 8276 *Audio Hardware*
11-12-94 15:05:00
From: DAVE CAIRNS
To: KINHLUAN NGUYENNGOC (Rcvd)
Subj: REPLY TO MSG# 8088 (LINAEUM OPTIMUS)
KN> one of these days, Dave, you're going to end up buying the franchise..
> RS stores are franchises, aren't they ? they look profitable, too...I've
Yeah, and you know, I don't really like the places very much...
KN> so who's ahead now, LX4 or LX5 ? btw, one local store had a (manager's
> ?) sale of the Lx4 for $69, all the others are $99
LX-5 by a mile. The LX-4 can work very well with a subwoofer,
but is just too leanly balanced to make it easy as a stand alone
speaker. With about $5 worth of stuff (next installment on the way) and
a few hours of time, the Lx-5 sounds like a $1,000 pair of speakers. It
has its faults, but is VERY easy and musical.
KN> what are the stands and how high are they ?
I'm ashamed to admit... They are about 17" high and not optimal
at all, just handy. I think that the correct height is going to be
about 22 or 24 inches, but haven't easily managed to do that in a stable
manner. Yet. The speakers are tacked down to the stands with some
American (DAP?) immitation "blue-tac." I guess I should lug out the
SL700 stands. But they weigh so much...
Msg#: 8278 *Audio Hardware*
11-12-94 16:48:00
From: DAVE CAIRNS
To: ALL
Subj: REPLY TO MSG# 8089 (LINAEUM OPTIMUS)
Another Chapter in Optimussing the Radio Shack Linaeum LX-5.
Since I've decided to keep these I made a (very slightly) more
invasive modification. I bypassed the crossover capacitor with a
polystyrene cap of .01 mF value. It cost me $.50. The midrange and
treble both benifitted. There is even less grain and there is a
"faster" more extended sense to the highs. I won't be undoing this one.
Latter:
I've been listening, looking, and pondering for a few days and
it occurs to me that the funky little plastic traylike thingie that the
tweeter is sitting in can't be helping anything. It has about a quarter
inch lip in front and back and even more on the sides as well as four
plastic posts for the grill to attatch to. I stuck some foam on the
inside so that there would be less reflection from the lip back to the
tweeter and found that the treble and midrange were improved yet again.
Since I had developed this dislike for that tray, I decided to
see what I could do about it. Remove the four screws on the tray and
the two that attatch the tweeter and it all comes loose. Carefully pry
up the little plastic cover over the tweeter wires and you find that you
can unplug the tweeter. With the tweeter and tray off, I am down to the
cast aluminum box itself. Well, lets just bolt the tweeter back on.
That works ok, except those extra four screw holes need to be covered.
I used the gummy black junk that was already in the tray (to hold the
grill still and keep it from rattling) to cover the holes. The sound is
better, but there must be some reflection from that aluminum top.
After a trip to OSH, I had a few dollars of eighth inch thick
sponge rubber and eighth inch thick felt. After near to an hour, I had
cut the rubber and felt to the size of the top, made the necessary holes
in them, and mounted the tweeter on top. The rubber covers the entire
top while the felt is on top of the rubber but has a cutout the same
shape as the tweeter itself. In other words, the tweeter bolts on top of
the rubber, but is surrounded by the felt. All this stuff is held in
place by the original screws. The tray is gone. I'd guess that felt
alone might work just as well, but hey, I couldn't make up my mind.
There is even less spit and splash in the upper midrange and treble.
The treble is very extended and fast.
The sound as it stands now:
This tweeter now rivals any that I have heard. It is better to
my ears than that in my Celestion SL700se. Better than a Focal T90 or
Dynaudio D28af. Better than that of a friends Vandersteen 2Ci. In the
same range as my Martin Logan Aerius' treble. (I really don't want to
know which is better right now :-)
The midrange is very smooth and unfatiguing. It is still a bit
recessed sounding but clean, pleasant, natural, and undistorted.
There is no low bass, but the mid bass and upper midbass
emphasis makes it seem as if there were. With straws in the port, I
find the bass full and warm. Without the straws, it is too "boomy."
The imaging and soundstaging are great. There is a lot
of presence and space. The whole end of my listening room seems to
disappear into the recording venue. There is a three dimensional
presence to instruments and people. Maybe I should say that voices
sound as if they were/belonged to people.
The overall sound is big with great width and good depth. All
this with my Technics SA-GX 550. I guess I should try the tube stuff...
Overall, I have heard multi-thousand dollar speakers do worse. I
can live with these better than I could my old Theil 3.5s. A friend
owns Vandersteen 1B's. I don't know which I would rather live with.
These modified Radio Shack speakers sure do detail and space and treble
better though...
---
SLMR 2.1a We all live in a yellow subroutine.
Msg#: 8607 *Audio Hardware*
11-16-94 16:46:00
From: DAVE CAIRNS
To: RICHARD B ROSEN (Rcvd)
Subj: REPLY TO MSG# 8484 (LINAEUM OPTIMUS)
RBR> I'm really enjoying this. I'm having so much fun reading this stuff, I
> think I'm gonna get a pair of LX-5s.
You know, as I see it, all you have to lose is some time. Most
of these mods are totally reversable with no damage to the speakers.
Buy them, take off the grills (careful with the tweeter grill,)
stuff
some 5 inch drinking straws in the ports and break them in. If
they
don't sound really promising after a few weeks, take the straws
out, put
the grills back on and return them. If, on the other hand, you
like
them, the other mods are not much more difficult and are also
reversable. Go for it, but be sure to let us know what you hear.
Msg#:10075 *Audio Hardware*
12-02-94 20:07:00
From: DAVE CAIRNS
To: TOM KELLY (Rcvd)
Subj: REPLY TO MSG# 9728 (LINAEUM)
Tom,
Have you tried any of the tweaks and modifications to the
LX-5's
that I posted here? At least get yourself 20 straws cut to about 5
inches and cram them into those ports. The ports become much more
well
behaved and the "boomyness" is improved. Oh, the other changes
make
them sound much more open and help them image even better...
I still really like these. They have faults, but they are
fun
to listen to and the treble (especially when you make the modifications)
is right up there with the best.
Msg#:10088 *Audio Hardware*
12-02-94 20:56:00
From: DAVE CAIRNS
To: MIKE FENECH (Rcvd)
Subj: REPLY TO MSG# 10002 (LINAEUM)
MF> As I mentioned before, piano and female voice is this speaker's forte,
> IMHO, assuming you like it sweet. Actually, the sweetness maybe from my
> AMC...this is why I want big money to try them out. I did bring them to a
I've tried the LX5's with some other equipment now even if it
doesn't qualify as Big Money. They are always sweet...
I replaced the Technics SA-GX550 with a conrad-johnson PV-5 and
a pair of Quad II monoblocks running GEC KT66's. The Quads, which sound
great on most speakers (can you say magic midrange?), didn't seem to add
much to these speakers. They sounded good, but didn't do much more of
that "palpable presence" thing. The speakers already have a liquid
midrange and very good imaging like tubes can give. The Quads
didn't add their usual magic. Net result, 50/50 Technics vs tubes.
Next up, keep the PV-5 in and substitute a Forte 1a class A
power amp. Wife says "that's the best I've ever heard the Forte sound."
But you have to understand the context of this remark. We've spent years
trying to love this amp. It has great detail, imaging, and a really nice
sense of "quiet." If it can handle a speaker, it has real nice control,
pace, and dynamics. It just doesn't sound very musical to us -- to
untube like and hard and glassy. The LX-5's really were a lot less
laid-back with this setup. Imaging was very good and some instruments
and voices sounded "real." This amp makes me think that this speaker,
while efficient, is not a real easy load to drive. The LX-5s really
benifit from the control and drive this amp has. The amp is pretty
high current and able to drive hard loads. Too bad that it still
sounded like the Forte...
Next, again the PV-5 but with a Carver TFM-45. Only 375 watts
per channel. Not quite as much control as the Forte, but still a real
nice sense of "solidity." The tonal balance is a lot easier than the
Forte, but a bit too dark. This amp basicaly sounds "nice" and easy to
listen to on the LX-5 with good imaging and some 3D quality. There is
some grain, and it just doesn't quite come alive. I'm still playing
with this combination.
My guesses: the right, high current solid state amp is going to
bring these things to life -- another, higher powered tube amp
might also make them sing. Overall, I'll probably go back to the
Technics -- who wants to waste a KT66 when it doesn't buy you magic...
The rest of it: JVC 1010TN CD transport, Adcom DAC, homemade PBJ
work alikes, Monster M-1 speaker hose. Electronics about ten times the
price of the speakers...
Msg#:10089 *Audio Hardware*
12-02-94 21:07:00
From: DAVE CAIRNS
To: BRAD SANDERS (Rcvd)
Subj: REPLY TO MSG# 10044 (LINAEUM)
BS> Possibly - but I've found that rolling off the bass with the ports
> open gives the best of both worlds. They DO have a nice, warm sound
> down there...they just need some filtering.
Straws... and tack them down with some blue-tac-alike to some
firm stands. And the mods help too... (but not the bass)
BS> One thing I have discovered (for all those LX5 owners): Move the tweeter
> voice coil through it's maximum excursion a bit. This'll help distribute
> the ferrofluid better in the gap (it doesn't seem to be very carefully
> applied in mine).
Another interesting observation is that this speaker seems to
warm up at about 15 minutes. I've had this with electronics, but I've
noticed the LX-5 "blooming," "opening up," and getting easier at about
the 15 minute point with a number of different electronic combinations.
Msg#:10162 *Audio Hardware*
12-03-94 15:30:00
From: DAVE CAIRNS
To: MIKE FENECH (Rcvd)
Subj: REPLY TO MSG# 10149 (LINAEUM)
BS> "You say sweet - I say glassy..."
DC> I say recessed...
MF> What does 'recessed' have to do with 'sweetness'?
I was just making my comment on the midrange. I don't hear
glassy at all. I do hear sweet. I still hear recessed, but the
more I play with these, the more I find that they take on the
character of the amplifier used.
Current fave amp is the NEC A10-II (reviewed, sort of, a few
times way back in Stereophile.) Feeding the Adcom DAC directly
into the power amp section of this 54 pound (!) integrated
allows me to use the built in "passive" preamp. In this
connection, the signal goes straight through a pair (dual mono!)
of Alps volume controls. This amplifier is rated at 70 watts
per channel but does 140 watts into 4 ohms and 275 watts into 2
ohms. It really kicks these LX5s around! The sound is clean,
detailed, easy, smooth, and dynamic. The mids are still sweet
but not so recessed.
I'm finding that these speakers need a strong amp to do their
best. I think that they deserve something that can handle
difficult loads better than the Technics. I wonder if your
observations about their sound on male vocals and more complex
music may be related to the AMC running out of steam.
Willy Nelson and the Persuasions (what a great idea for a
group?) sound real good here. Maybe Brad's comments about
"glassy" come from some similar amplifier/speaker interaction.
Maybe a Krell would be about right ;-)
On a related note, I'm now using a better crossover cap. I have
some polypropylenes bypassed with polystyrenes hanging on the
back because they are so big that I'm afraid that they would
change the bass tuning if I put them inside. Smoother, sweeter,
more resolution. "Every day in every way these speakers are
getting better and better."
--
Mike Fenech
mike_...@netsolve.net
Date: Tue, 10 Oct 1995 10:40:38 -0500
From: mike_...@netsolve.net (Mike Fenech)
To: Phil...@gnn.com (Phil Brown)
Subject: Re: Modifying Optimus Pro LX5 / Linaeum
More stuff
----------
Tweeks from Bob Figaro:
So I bought a couple of RS LX5s a couple of months ago to use with the video
system. Also listened to them on my main system. They sounded good but were
somewhat "tizzy" and lacking in lower end definition. They did image well,
however. In-room response using MLS method indicated about a 5db spread from
around 95 Hz to 9000 Hz followed by a droop to 15kHz and a rise at 20kHz. All
in all, not a bad performance for a little box in my ratty SoCal
flexible-walled, rotten construction room so, I decided to invest a few bucks
and improve the guts of this little creature. BTW, MLS testing revealed no
appreciable effect by removal of the grill-if anything the plot is a tad
smoother with the grill on (tweeter grill). The woofer grill seems to
take some life out of the sound, however the visible response reveals
little if any differences. So much for objective testing of subtle
effects. Anyway, I a) replaced the cored inductor with a 1mH 14 gauge
aircore coil which fits nicely in the bottom of the enclosure, b) replaced
the tweeter cap with 6.2mF of Sprague (North Creek - I like these caps,
compared them to several others for actually driving a speaker. The
Sprague cap actually increased the output by about 2db over the original
Nichicon cap and sounded significantly less hashy while being
substantially less veiled.), c) lined the enclosure with ORCA "Black Hole
Five" - a wonderful killer of internal reflections. The "rap" test of the
box is satisfyingly "dead." and d) listened to the first modified speaker
by itself for a couple of hours in amazement. Coloration in the lower
register of the female voice was now gone. Upper end had a silky yet
incisive quality and overall the speaker was much less colored than the
unmoded unit. Cost for the project was about $17 for the coils, $15 for
the caps - the Black hole came from a previous project but you don't need
much. Improving the original component quality and dampening of the
box
make the LX5 into a very satisfying speaker. The need for a sub
under it
still remains but on most music you do not miss the very low end. I
tried
the whole system (two speaks moded) with and without my Velodyne
ULD18IIs-
of course it made a difference but not as much with "normal" music
as you
would think! The job of upgrading these speakers is a little
"touchy" but
for those who probe into the guts of a 3400 it would be a piece of
cake!
Also, a word of caution, do not over-drive these speakers! The
tweeters
will destruct if you feed them too much broad band noise as one
might do
with a MLS test with the low sampling rate low frequency mode of
the IMP.
How do I know this? Well, guess! Heh,heh /:-( I just had to test
them
again after I had listened late at night- BIG mistake! Oh well,
new ones
on the way.
I know Albert suggests throwing out the LX5 and starting over. But
let's assume
that we won't do that yet. Just read the SP review of the LX5 and I agree with
the findings -even my MLS and impulse data look similar. However the "lack of
involvement" problem really is significantly diminished by the component
changes. Further, the box problems are VERY significantly reduced by the use of
Black Hole Five. In addtion, the Nichicon 6.2 uF cap used in series with the
tweeter is terrible sounding. Several surplus films sounded better driving the
midrange of my Accuton 77 which is very revealing for comparing component
sound- But the Sprague North Creek cap was wonderfully detailed without being
hard to take. The low end problems of the LX5 are due to the little ferrite
cored inductor and a poorly damped box. I have found that air core at least 14
gauge sounds much better in an inductor. The major downside of the LX5 is that
the system is inefficient and, at best, cannot make a lot of noise. I know some
of you have these critters (this is where I heard about them). The straws help
a little but are pretty marginal in there effect if you do the box over. BTW
the tweeter grill does not alter the sound significantly, nor does it affect
the MLS plot to any extent. I would be interested in feedback if any of you try
this stuff. Best regards, Bob F.
Msg#:22390 *Audio Hardware*
02-27-95 18:18:13
From: William Eckle
To: Kalman Rubinson
Subj: Linaeum Tweets 1/2
Hi Kal:
More info on the Linaeum tweet, thought you might be
interested:
From: Paul Kubicz <pk...@p.imap.itd.umich.edu>
I had a chance to listen to the Radio Shack models and, impressed by my
results, I called Linaeum to confirm my thoughts. Here's some background
on the tweeter-of-the-week:
There are two sources for current Linaeum drivers: Linaeum corporation and
Radio Shack. There are serveral differences between the two drivers.
First, the Radio Shack model includes a piece of plastic mounted on top
to 'reduce the possibility of driver damage.' Unfortunately, it also
reduces vertical dispersion from 24 degrees to 21 degrees.
Secondly, the Radio Shack models are assembled in Japan, while the
Linaeum models are hand-assembled at their facility in Portland (this
could be either a benefit or caveat--take your pick). The models assembled
at the hands of the Linaeum employeed will, however, be awarded a 5-year
warranty as opposed to whatever mediocre policy Radio Shack happens to have.
On the other hand, Linaeum will expect carefully each return to insure that
it wasn't (ahem) driven to excessive levels. Chances are, the Radio Shack
salesperson will just shrug their shoulders and order another (just
speculation, of course. On the other hand, given the typical RS consumer,
they may see blown tweeters all the time. Your return could be greeted
with similar skepticism. Anyone have experience with Radio Shack & blown
tweeters? C'mon, you can tell us, we're here to help. Just put on this little
white jacket...)
In any event, besides these production/policy differences, the two tweeters
are identical. The price on the Linaeum model will be about $40-50, and they
won't have any to sell for about a month. Apparently, several positive
reviews (in HFN/RR[!] and 'Sound and Image') have caused a sales surge. The
price of the RS model is $49.99 and they are back-ordered until May 10, so
they're in worse shape than Linaeum. It seems like the model available
directly from Linaeum is the better buy.
The model that A&S has on clearance ($30) is the previous model. As Doug
mentioned, A&S claims that the model they stock has a lighter diaphragm.
They may be referring to the previous (to the A&S model, ie. 2
generations ago) model; the new model is made with a lighter material
than the A&S model. In addition to the material change, they have made
the new unit 1/4" taller. This (in combination with a larger voice coil) has
resulted in an efficiency increase (89 dB/W/m @ 7.x ohms as opposed to
89dB/W/m @ 4 ohms), as well as a slight power handling increase. Steve
mentioned that, with the exception a very slightly warmer sound to the
new unit, frequency balance is essentially unchanged.
The wave launch, essentially the same in all models, remains the
(dipole) Linaeum's main selling point. Take your pick according to your
preferences.
I've listened to the Radio Shack Linaei and was favorably impressed. The
music, which included lute-song (Dorian), Jazz and crowd noise (Telarc),
guitar (Toad the Wet Sprocket), and orchestral (Teldec/Harnoncourt's
Beethoven) was chosen with the tweeter (Linaeum) portion of the speaker
in mind. Note that the listening was done within the confines of the RS
environment...
I found the basic sound remarkably clean and non-metallic, with no
traces of resonances. I'm very particular about the upper octave, and
the Linaei satisfied. The lute and guitar had the bite they should, and
the upper-frequency transients of the crowd noise (clapping and whistling)
were naturally clear and sharp. Too many of the commercial speakers in the
<1 kilobuck range that I've listened to have a slightly rolled-off
upper
octave which dulls the sound and robs it of believability (and
that's the
story of why I bought my current speakers, Magnepan ribbons). This
is my
major beef with Martin-Logans, incidentally.
I paid less attention to the midrange, not knowing where the driver
was
crossed over (I'd guess 2-3kHz) and what the slope was. The
midrange did
have the remarkable airiness of a dipole, but I wonder if a certain
lean-ness I heard on the lute was a dip somewhere in the upper
midrange.
Interestingly, the transition from tweeter to woofer was easily
discernible, particularily on white-noise type material (either
background hiss or crowd noise) mixed with standard midrange/bass
material (piano or orchestra). The midrange music sounded boxy and
closed-in, with a huge spaciousness of the white noise/upper
frequencies (quite an eerie effect). I suspect this was due a least
partially to the slightly boomy ported enclosure as well as the
woofer
level being a bit higher than the tweeter. It seems that either a
bipolar or sealed-box (low Q) mid/woofer is in order.
The radiation pattern, as Doug suggested, is interesting (ie.
lobey).
While Steve, the Linaeum rep., suggested a 'two beer cans' analogy
for the
tweeter, butt cheeks popped into my mind. When listening to them, I
mused at
the thought of being mooned by a transducer...In any event, they do
lobe,
with a deep high-freq. null (ahem) centered directly between the
cheeks (ie.
exactly on-axis). Not where you'd expect a null...The best balance
seems
to be 20-40 degrees off either cheek, with 30 being my preference.
Oddly,
as you step further off-axis, the midrange level decreases, but
some
high-freq. energy is still present. The same thing happens, even
more
dramatically, when listen to from above--virtually all that's left
is the
upper octave. I wonder if these aren't diffraction effects
unleashed from
diffraction hell (the tweeter is surrounded by a steel cage secured
by 4
plastic posts). Then again, RS is hardly an anechoic environment,
and it's
possible I was hearing reflections from a nearby surface (they only
have
about 2' of speaker cable on these things).
Given that radiation is optimum off-axis but poor directly on-axis,
a
dipole, heart-shaped radiation pattern seems to be the best visual
analogy.
This, interestingly, is similar to the DCM Timewindows (not
dipolar), which
angle one tweeter 35 degrees inward and one (for ambiance) 35
degrees
outward. On the other hand, a typical planar-magnetic (a la Carver)
has a
figure-8 radiation pattern, with strong on-axis radiation which
tapers off
off-axis. It seems to me, then, that these drivers would be a poor
match
for each other (in fact, the Linaeum seems like a renegade member
of the
line-source family).
Like a typical line-source, the response is limited vertically.
Expect
the best listening position to be within 20 degrees vertically, 30
degrees
off either side of the horizontal axis. But, since you're getting
some last-
octave response almost anywhere (except on axis), it sounds
subjectively
like you're in a decent listening position. (I don't know if this
is true
for everyone, but I realized that I unconsciously judge how far
off-axis I
am by how little 10-20kHz energy I'm receiving. These speaker are
deceiving
in this aspect.)
With 3 of the 4 cheeks radiating off of a wall (the 2 back ones off
the rear
wall and the front-side one off of the side wall), the speakers
sound
stunningly spacious, even on the bookshelf on which I listened. In
fact,
this tweeter looks like an excellent solution for someone who wants
an
airy and spacious sound but is condemned to actually having to
place their
bookshelf speakers (gasp) on a bookshelf. What we have here in an
inexpensive solution to the direct/reflecting sound issue that
doesn't use
cheap cone tweeters; a truly original design.
Incidentally, their diffuse radiation pattern will make them great
for
surround speakers.
The frequency balance may or may not need some work (I'll leave
that
question to those who have paired them to properly to high-quality
midranges/woofers), but the overall sound is very satifying. As an
extra
bonus, they're a great conversation piece; even your companion will
ask
about them. I'll definitely be buying a pair.
Thank's for tuning in. This intriguing tweeter leaves much to be
discussed,
and I hope others who have purchased these units already post on
the sound
as well (esp. after in-depth listening). One can only glean so much
information from a 1 hr. trip to the mall.
Paul
------------------------------------------------------
Paul Kubicz | pk...@p.imap.itd.umich.edu
University of Michigan |
--
Mike Fenech
mike_...@netsolve.net
Date: Tue, 10 Oct 1995 11:38:29 EDT
From: CC01...@brownvm.brown.edu (john 015)
Newsgroups: rec.audio.high-end
Subject: Re: Modifying Optimus Pro LX5 / Linaeum
In article <45e18h$5...@agate.berkeley.edu>, Walter Clark
<cl...@babagi.enet.dec.com> said:
>I have modified several pairs of the old Minimus-7 over the years.
The
>original speaker (with a Japanese made rubber surround woofer) was
a
>sealed cabinet as was the second generation (with the ROC made
driver
>and foam surround). The third generation added a 1" diameter port
>with no changes to the driver or enclosure whatsoever. The effect
was
>to add a bump of nearly 6db at about 150Hz.
>
>Ignoring the crossover in these speakers (which was only a little
bad
>in the original but became a joke in the ones with the ROC woofer)
the
>sonic effect of the added port was to overly warm up the upper
bass as
>is to compensate for the lack of anything under 100Hz. Side by
side
>(or easier yet, just plugging the port) demonstrated just how
mistuned
>the unit was with the port added and how one-note-bass it became.
>
>Now this is not to say that RS didnt accidently tune the woofer,
>cabinet and port to some accepted Thiel-Small characteristic, but
>based on my experience with the Minimus-7 (Pro7 later) I would be
>surprised. I would suggest you might want to measure the low end
>response and if you observe a big bump around 100Hz (tubby or one
note
>bass is usually the result of vent/cabinet/driver mis-tuning) plug
the
>port.
I didn't like the highs or the lows but the bottom cleaned up a lot
after I stuffed the ports shut.
I suspected that woofer cone breakups was behind the high frequency
glare (because everyone spoke highly of the Lineaum tweeter). I
figured that I can fix that easily with a better crossover or a
better
woofer.
I broke out the IMP speaker measurement system and took a look:
Contrary to me suspicion the woofers were desent and showed good
left/right matching. I seem to remember the hump sits at about 150
Hz.
The tweeter on the other hand had all kinds of valleys and peaks.
Taking off the protective grille and putting foam on the edge
closest
to the tweeter did change things but not for the better.
john
Date: 11 Oct 1995 18:54:00 -0400
From: brad.s...@circellar.com (Bradley Sanders)
Sender: j...@Graphics.Cornell.edu
Newsgroups: rec.audio.high-end
Subject: Re: Modifying Optimus Pro LX5 / Linaeum
Phil...@gnn.com (Phil Brown) writes:
>I'm looking for information on improving the crossover and
possibly
>replacing the bass driver on the Optimus Pro LX5 speaker from Rat
>Shack. Has anyone been successful in modifying this speaker? The
pair
>I have has a rather flabby mid bass, with plenty of vent noise.
Stuff the ports with soda straws. Cut a handfull of'em to about
2.5"
long, then shove'em in the ports. This'll look like a cross section
of
corrugated cardboard, and acts sorta like a variovent. If you do
this
right, it'll solve the vent noise problem.
I think the only "crossover" is a 6.8uF cap. So, bypass it with a
.1uF
film cap - or replace it altogether. I use OS-CONs. This is a
pretty
low impedance driver, so crossover parts quality really shows.
You can also remove the plastic "cap" (and the metal grille) from
the
speaker. Although I doubt the metal grille really hurts dispersion,
I
don't trust it not to vibrate - and the plastic piece it bolts to
is
crap. My own speaks use the 'real Linaeum" tweeter, and I've found
it
worthwhile to make the surface these mount on as dead as possible.
I
myself use REAL (rabbit) felt. Don't use the cheap felt, because
this
stuff is just plastic threads and is no less reflective at high
frequencies than the stuff you're replacing.
Mount the tweeter back to the speaker with foam weatherstripping
(or
something similar) between the tweeter and the speaker cabinet.
Don't
forget that ALL points of contact must be isolated in order for
this
to work: If you just put weatherstripping underneath then have
metal/plastic contact on TOP of the tweeter, it's still gonna
conduct
vibration from the cabinet. Touch the edge of the ribbon very
lightly
with the speaker playing, and note how much up/down vibration is
being
conducted. Try to minimize this. I have used foam weatherstripping
under the tweeter, and a screw on either side with a soft neoprene
washer under the head. It's not 100% effective, but it's the best
I've
(thus far) found.
I've not been INSIDE the LX5 myself, but if they're like the other
aluminum speaks in the ratshack line the boxes are pretty LIVELY.
Go
to the building supply and buy a bucket of roofing cement and a
cheap
1" wide brush with a long handle. Remove EVERYTHING from the
cabinet,
and liberally apply this tarry goo all over the INSIDE (I know this
is
obvious, but believe me - you don't wanna get ANY on the outside.
Be
careful). If you REALLY wanna damp it, you can get heavy tar strips
(concrete expansion joints) from the cement supplier. Use the
roofing
tar to secure these to the walls of the speaker (much cheaper, and
just as effective as "audiophile tar").
You'll also want some acetone handy to wash the roofing cement from
your hands. Do this before you touch anything you care for - and
keep
the rag handy, 'cause you're gonna get this stuff all over you
while
putting the guts back in (right, Breir Rabbit?).
| Brad Sanders, CEO, International Moustache Wax |
| http://www.geopages.com/SunsetStrip/1303/ |
-Phil
http://www.best.com/~duda/PBMAIN.html