upgrading the Optmus LX-5 & PRO-X77 Loudspeakers - diyAudio
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Old 18th June 2001, 09:30 AM   #1
ppl is offline ppl  United States
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Has anyone tried any upgrages to radio Shack's LX-5 and Their PRO-X77 Mini speakers?
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Old 18th June 2001, 02:04 PM   #2
Eric is offline Eric  United States
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I'd be curious to hear from someone who has done this also. I have a pair of the Lx-5s for my office and have been contemplating the upgrade.
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Old 28th August 2002, 04:00 AM   #3
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Default LX5 Upgrade

There are a few places on the web for info on upgrading these speakers. I have a pair and have done a few modifications to them. I have plugged the ports with cork (off a few wine bottles), applied Dynamat to the inside, reversed the phase of the tweeter, and stuffed with poly-fil. They sound great-- however the bass below 100Hz is gone. I am building a sub woofer system to compensate for the loss of low-end.

I am also going to get two Seas 5" woofers to replace the stock woofer. They're about $38 at Madisound and suposedly have much better sound in the mid-range.

Have fun.
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Old 28th August 2002, 04:02 AM   #4
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OH yeah ... some links to LX5 mods -duh

LX5 mod

or just search with Google
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Old 28th August 2002, 04:34 AM   #5
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Quote:
Originally posted by swirv
some links to LX5 mods -duh

LX5 mod
The above are Larry van Wormer's heavy duty mods.

Here are some simpler (and way cheaper) mods Larry did as well (the oil-based clay is no doubt similar to duct-seal available at HVAC wholesalers):
__________________________________________________ _
I've been spending a bit of time working to improve the stock woofer on
the RS LX5 speaker, and have tried a couple of changes that work pretty
well. They should apply equally well to other drivers:

First of all, the "Mod Podge" coating I tried a week ago continues to
work just fine. It has significantly reduced the cone resonances.
(Thought I should point this out, since many other coatings I tried in
the last couple of years worked well initially, but became much less
effective as they fully dried. The Mod Podge hasn't been affected by a
week's cure time, and appears to be pretty much stable now.)

Today, I tried damping the woofer basket and cabinet with oil based
modelling clay. As usual, it's very effective, and significantly reduced
vibrations, as shown by a much better waterfall plot. Turns out some of
the resonances I was sure were in the cone were actually in the cabinet.

Specifically for the LX5, I added about 2 ounces to the woofer itself,
on the four basket ribs, then added 6 ounces to the cabinet faceplate
and other sides. The clay seems more effective if added as a deep rib,
rather than as a thin layer over the whole face. That makes sense to me,
since the panel vibes will then work the clay more.

Together, these very cheap mod's make a useful difference to the
speaker's output, and especially the woofer. I believe in the States you
can get a pound of the clay for one or two dollars, and the Mod Podge is
pretty cheap as well (get the smallest amount you can of that, one ounce
is more than enough for a pair of woofers.) The high frequency "zing",
due to woofer breakup, which I find irritating, is now gone.

Larry Van Wormer
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dave
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Old 28th August 2002, 05:04 AM   #6
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Default more info

Planet10,

If you have more info on this lx5 mod or others I would love to read it. I am in the process of moding mine and have toyed with the idea of building a TL sub for them ( got the idea from your site about a month ago-- very cool ideas)

TIA
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Old 28th August 2002, 05:11 AM   #7
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Default Re: more info

Quote:
Originally posted by swirv
If you have more info on this lx5 mod or others I would love to read it. I am in the process of moding mine and have toyed with the idea of building a TL sub for them ( got the idea from your site about a month ago-- very cool ideas)
Larry's are the only one's i've seen, so you have most of it in the link & the post. The puzzlecoat/Modge Poge & Ductseal mods are pretty standard tweaks you can do to almost any speaker. Others are better wire and box bracing -- i always work towards stiffening the box and pushing resonances out of the range where they would be excited as opposed to mass damping.

dave
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Old 28th August 2002, 06:41 AM   #8
ppl is offline ppl  United States
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Thanks alot guy's for your input. I use two of the LS-5's and two Pro77's on my PC with a 5 Ch LM-3886 based Gain card Clone and allready have a sub so will try the other mods
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Old 29th August 2002, 12:15 AM   #9
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have a set on a secondary system.Did the "straws in the ports" thing first.A minor improvement but , tightened up the bass a tad.
Next I removed the top screen and the mounting plate between the tweeter and main enclosure. I replaced the mounting plate with a 1/2 " thick piece of felt (carpet backing)
This removed some of the top end irritation , the slight screeechy tendency (though not all,not even close)
Next up was to add a low pass filter to the mid-woofer.A simple coil that I can not remember the value of off hand.This was the most apparent improvement so far. The "unfiltered" woofer went up to about 3.8khz and it got pretty ragged in this area.
and then did the tweeter cap replacement.
results ?

Not bad for the investment but still a tad "shouty" a higher volumes , and when pushed the Lineaum tweeter has a nasty habit of blowing up.

I finally ended up replacing the mid-woofer with an SEAS unit (again I do not remember the part number off hand),adding a steeper slope to the high pass filter, and mating it with a subwoofer.
The sub was the missing link ,but still does not like high SPLs.These tweeters are not real durable.
When the add on lineaum tweets were discontinued i purchased three pairs at three dollars per.

BTW-I have the LX-5 , X77 and LX-4.
The LX-4 RULES !
Kevlar woofer , monopole tweeter and actual oiled walnut cabinet.Sounds great in my bedroom system
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Old 29th August 2002, 05:47 AM   #10
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It sounds like you guys have too much time on your hands.

You have junk speakers and try to make them better by modifying everything including the replacement of the woofer and crossover. You admit the tweeter can't hack it but still you persist.

I don't understand why you don't put the RS speakers in the trash where they belong and build something decent.

Can anyone explain your line of thinking to me?
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