upgrading the Optmus LX-5 & PRO-X77 Loudspeakers

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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.
Joined 2001
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swirv said:
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

more info


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)

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Re: more info

swirv said:
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.

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
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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Bill Fitzpatrick said:
Can anyone explain your line of thinking to me?

The challenge?

Like souping up a Chevy Chevette.

Some people don't have the facility to build a fresh box, so use what they can. Personally i wouldn't go further than tweaking what exists -- XOs are fair game IMO.

The tweeter is not a bad one, just needs a better(and higher) XO than provided.

And some of the RS stuff are real sleepers -- the 40-119 and 40-1354 for example.

I agree to an extent. RS has had a few gems in there past. The LX5 is a mass produced replica of a speaker designed by Linaeum. It even has a Linaeum dipole tweeter. I admit there are flaws in this speeker, but a little fun woking them out--and you have a gem. This is not the first or only time a reputable company has designed a product that wore a RS logo. Moog once made a synth for them. A freind of mine had it and woluldnt sell it to me for any amount of money. Moog is considered to be one of the very best analoge synth you can own/find/build. Im sure if someone found another RS moog and modified its filter it would be not only a beast of an analoge synth, it would be fun.

A lot of us DIY'ers like to take something old or cheap and make it into something nice or us it for some purpose it was not indended...like the amplifier out of a console tv as a monitor amp, or bathroom tile as a kitchen table-top, ect.
Bill Nice to Know there are other DIy'ers in Eugene. regarding the LS-5 i use these and an LM-3886 Based Amp on My PC and sounds alot better that some Hightly regarded Deicated PC Speakers. Now on my Hi-Fi I use my Own design Loudspeakers Based upon the madisound 12" Dual voice coil Sub, A vifa 6.5" Woofer an MB quart 2" metal dome with the matching 1" Dome. The Sub is in a Vented box with an outboard 2ed order filtor with an User adjustable "Q'. so yes i have been down the Heavy DIY road but nowdays I havent the Energy to do this kind of thing so i stic to small projects like Headphone Amps and upgrading things to get more use out of them. BTW nice Web site you have do you think that your firm might offer an Win XP version of Virtual ears? Have a Nice day:) :)
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ppl said:
other DIy'ers in Eugene

ppl -- why don't you pop that tidbit of info into the location field in your Profile (User CP button at the top of the page)

do you think that your firm might offer an Win XP version of Virtual ears?

Hey Bill, while we are at it, what is the likelihood of an OS X/Unix version?

Actually, the program is called "Visual Ears", not Virtual Ears.

We aren't Windows experts and don't know why the program won't run under XP. The program was originally written for Windows 3.2 and we did something very sneaky in a C coded dll which allowed for 32 bit operations. I think XP is unhappy with that.

As for Unix or Mac, we don't think so . . . but thanks for the interest anyway.
LX5 Mods

Help !
Read Larry Wormer's and Eric van Wallins mods guide and replaced the stock LX5 bass drivers with the recommended SEAS M14RCY/P 5" woofers - much smoother but I've lost 2 octaves of bass (not that there was that much to start with). I've not pursued the crossover mods as I wanted to see if things were heading in the right direction first.
Am I barking up the wrong tree - I presumed that the crossover only really affected the range where the units "crossed over", not the ultimate extension of the bottom end, so have not attempted a change here (I'm no speaker engineer and can barely solder, let alone understand circuit diagrams).
Can't find anything further on the subject from Eric or Larry (and no contact details other than the website). Any suggestions welcome.
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