Realistic Optimus Pro LX5 Speakers Repair & Mod

[@R.AudioElectronics]

Not to nitpick but I am- when replacing screws into plastic it’s best to not cut new threads for the sake of repeated removal of screws. So the technique would be to place the screw in its place and turn ccw until you hear or feel the treads line up and then continue to screw in as usual. I’m not saying this wasn’t done here but the opportunity presented itself to be shared. Thanks Tony always enjoy your videos

[@lucasphelps7868]

wise knowledge there

[@PilotInCommand777]

I found a pair of these at a local thrift store that were pretty marked up and used a white magic eraser cleaning sponge by rubbing the marks lightly and it did a really good job cleaning them up.

[@PerthSoftware]

I have a pair bought many years ago. I disconnected the woofers and just used the tweeter on top of a diy tower with a good quality 7 inch mid-woofer. Sounded great. Later I replaced the woofers that fitted, and were better. So today they are the rear speakers in my 7.1 setup.

[@1ring2rule3pigs]

Do you know if these are the same tweeters in the Pro LX10?

[@alexispieltin9379]

It's an interesting video for anyone having these Realistic products at hand. I doubt these could be found in most countries after the mid 90's. I'm still impressed with the relatively well built product with a molded metal enclosure wich was an interesting feature when used close to CRTs! And it's relatively nice woofer motor is something you would never find in the low cost "shoebox" generally sold to people... I guess the original woofer could be refoamed, but you know it's always a delicate task wich can cost relatively high compared to the new ones you have found. A new suspension, plus center dust protection, centering Mylars, glues and eventual shipping costs, plus a lot of time, represent a budget I would only consider with some of the best brands or some too expansive to replace with originals. And you always have to check for wirings, coil and rear suspension wich are also critical and have to be replaced prior any other task. Here with new loudspeakers set, a simple coil check is always the minimum. The other idea to close the air ducts is no necessary a good idea. When it comes to loudspeaker design, any enclosure has a volume proportional to the speaker mechanical and electrical impedance, and the Q factor is a good indication to a closed or open design. The result is you need to test and measure your speaker to calculate the resonance volume of your enclosure, with a second law that tells closed ones needs larger volumes! Another deriving law is you generally can't use the same speaker in different type enclosure, nor close air duct directly. Solutions are available, like filtering foams or laminating labyrinth, but here designers have apparently used different length ducts. Anyway, the final result is difficult to check with a KZbin video, specially with limited recordings you can use. One of the best test is with human natural voice, from opera to more modern content, as far as they're recorded without computer mod... I suppose these miniature speakers are some kind of best compromise and a decent beginning for someone you want to introduce to HiFi. You could also eventually find some amplified bass sub you can eventually modify with an appropriate low pass filter, some eventually have this kind of settings. Most passive subwoofers are filtered to suit specific speakers and are not specially the best choice when coupled to something different.

[@zulumax1]

Keep in mind these are a dipole tweeter, so the sound field is going to be a figure 8, with out of phase information firing out the rear. Without a front wall to reflect sound off of they may sound diminished in their output of the tweeters. On stands in a room they may have sounded fine depending on placement. That may be up to a 3db gain, something to think about.

[@poormanselectronicsbench2021]

I also have a pair of these, with, rotted foam surrounds. I researched the replacements you have used, and I don't know if you had noticed, but , the diameter of the inner mounting flange ( about 112mm) is in contact with the outer portion of the new driver surround (the Symply Speakers specs are for a "Hole cut-out: 4.59", which is about 117mm) that should be free to "flex", which, may not make a huge difference in performance, but, I would think that a more accurately sized replacement driver, or, re-foaming the originals, would be more in keeping with the original design (you might want to use your DATS analyzer to check mounted and unmounted, outside of the cabinet differences). I cant argue making changes to the crossover, as when I researched I did find info on some mods and improvements.

[@evanleebodies]

I've just replaced the foam surrounds on my pair of LX5's with one slight difference. Instead of replacing the surrounds with foam, I've opted to use rubber surrounds. Let me tell you folks, the bass response is way better than before. I put this down to the stiffnes of foam vs rubber. I bought both foam and rubber surrounds off EBay and was able to make a side-by-side comparison before replacement, the rubber surrounds were way more pliable so on they went.

[@charliezembillas3932]

Can you post a link to the rubber surrounds you found? Thanks

[@philhemenway3503]

I found a pair of these at an estate sale and refoamed them. I am quite pleased with the sound. Perfect for bench top speakers.

[@codezero6023]

Danny at GR Research would be shouting : cheesy parts! Thin wires, Ferris binding posts, small iron core conductor

[@PaulTardino]

Hahahahahaa

[@bobadkins7377]

I was gifted a pair of these about five years ago. They had been stored for a few years and yep, dry rotted suspension foam. I ordered repair parts from Simply Speakers and got that problem resolved. Glad I watched this, because of the improved crossover cap. Gonna try that, because I always thought these should have been developing more and stronger highs than I was getting, given the Linnaeum ribbons. I replaced them with a set of KEF Q150’s (which I broke in), now I’ll try the added cap and see what happens. Subscribed.

[@1ring2rule3pigs]

So, what happened?? 😮

[@alexbautista1891]

I have 4 of these speakers. I do not have any test equipment, just my ears. I set up an A/B scenario. "A" speakers with the crossover mod using the 4.7 mf cap, the other stock. Wow! What a difference. Mids and highs are more pronounced. Tested side by side with Queens Bohemian Rhapsody. Thanks for the tip.

[@claddagh1000]

Bought mine 25 years ago and they just split at the foam. Well worth it

[@bradstearns5384]

I had a pair of Pro LX7 loved them. The had the rubber surrounds on the 7 in woofers. Worked at the shack from 96 to 2005. Got them on clearance with my staff discount. I think I paid 120 bucks for the pair. Loved those ribbon tweeters.

[@fredoswego]

I have a set of these on my desk that I bought new from RS back in the 80s. Not a bad sounding speaker but what gets me is the imaging I get off them while having them on the desk not that far from my ears. I chalk it up to that wide-dispersion tweeter.

[@kevinfestner6126]

After your improvements, they sound very good. These would be ideal for a back speakers for a home theater.

[@jimc9823]

The carbon fiber cones look great with the enclosures - thanks for the video

[@markweikle5645]

I've bought those same ones, and I would've thought they were carbon fiber too, but they're green Kevlar. I agree they look pretty cool.

[@socksumi]

I replaced the woofer in mine with vintage Kef B110 and Kef 2 way crossover I had laying around leaving the cabinet and Lineum tweeter. intact. Excellent match to the tweeter. Bass was better but the improvement in midrange clarity was quite remarkable and it blended beautifully the sweet open highs of the Linaeum film tweeter. This made for blissful listening especially when matched to a decent subwoofer.

[@thecman26]

I actually had a pair of the Minimus 7s and ran them as surrounds back in the day. Loved em!

[@dpyles9396]

Very impressive improvement Tony! Well done.

[@adaboy4z]

I remember seeing these at Radio Shack back in the 90s as a college student! I sure wanted a pair because they looked cool.

[@gdemirjian]

I used the same exact drivers for replacement, and they are very good. Upon recommendation from a youtube video I packed the Cabinet with filler, but the resonance was not right so upon watching your video I am taking it out now. Great video. Thank you.

[@1ring2rule3pigs]

Did that fix it? Do they sound awesome now?

[@carlosoliveira-rc2xt]

The LX 550 with extra stuffing sounds very good in the bass and mids .

[@melbahouse5743]

the cone material on the new woofers is much stiffer , and that will give you a mid-range reproduction that is more efficient . you might want to change from a iron core inductor to an air core . may want to change value to lower woofer roll off , and lower tweeter frequency response .

[@billdepalma161]

Sounds a lot nicer then the original the minimus 7’s were great and no foam rot I think the RCA MINIMUS 7 a5 the end of the shack were really good the best and better power handling. In 83 the minimus 22’s were awesome 1 year only, made for wall mounting better bass only in silver. The shack made so many great speakers. Nice video miss the shack.

[@MrChristopherMolloy]

I gave a pair of these to my cousin decades ago and they're still cranking out tunes in his garage. Good enough for that.

[@mackfisher4487]

Tony I suspect that you could or have built some amazing speakers. You truly are a man of many talents.

[@IliyaOsnovikov]

I listen to these speakers in the mid 90-s. And as I recall I liked them a lot.

[@jimpalmer1969]

Your improvements were pretty amazing. It would have been better for the viewers if we could have heard the before and after modification using the same music clip and microphone setup. Also a subwoofer would fill out the base very nicely. THX Tony!

[@alecbruyns4490]

These speakers were not bad at all. Those tweeters are excellent. Do check them. The adhesive holding the ends of the ribbons can fail. The later models had Kevlar woofer cones, which had far too much ringing. I stuff things with fiberglass to tame internal resonance.

[@wattspeakers]

Honestly over the lapel mic and sitting next to each other instead of spread apart, they didn't sound bad and had more bass than I expected. I listened over decent headphones. I've interested in purchasing a pair of LX5, but recently got a pair of 5" RCA bookshelf speakers with the Linaeum tweeter. With a sub they sound quite good.

[@joseph9770]

I was given a pair ofthese for christmas when i was in my teens. I remember them sounding quite good. :-)

[@billdepalma161]

You did a great job never heard these sound so good awesome

[@RadioAirchecks]

I bought the RCA version of these when they came out. Had them in storage for a few years and sure enough the surrounds disintegrated. I replaced the woofers and they sound great. I even compared them to some Klipsch bookshelf speakers and they hold their own very well. Since you don't like this model, I suspect the RCA model from Radio Shack had some improvements in design.

[@publicmail2]

I have 3 pair of minmus 7, silver and black, great speaker, no failures. I worked at RS too. Funny thing is we did the inventory...

[@seanjoell]

Your Minimus 7 modification video showed you using software to test speakers, the stuff you got from Dayton Audio, would've like to see those test measurements on these for each driver separately and one with them combined. Thanks for the cool video.

[@111000100101001]

Great work in making improvements to a nice pair of speakers. I’m sure your daughter will enjoy her record collection with more clarity and dynamic range vs having to suffer through a Crosley cruiser ;)

[@donbustoarigato2997]

Definitely improved highs. I have the last iteration of these speakers with the yellow (kevlar?) woofers and I've always found the ribbon tweeter too soft, probably for similar reasons. I may use them as surrounds in a hometheater at some point.

[@redpill4431]

Been buying these for years and modifying them , very good imaging . Remember people laughing until I demonstrated them, soon changed their minds.

[@jked7463]

Yeah, alot of people judge by name instead of performance. The proof is in the listening.

[@noct_studium]

they really shine when you use a dedicated sub as well

[@boriken395pr]

Bravo! Great mod Man! I have the lineaum front side versión, good job!

[@nabman_]

Most 80s speakers suffered from foam surround degradation. Polk Audio was one of the few exceptions I know of.

[@davidbailey6350]

Thank you Tony, loved the video.

[@TheTrueVoiceOfReason]

You could always cut some Closed Cell foam plugs for the ports and see how it sounds with one or both plugged.

[@buitenb]

Nice "cooking "the new woofers ! I use a sound generator and a amplifier for that . Youre idea is a smart use of the 60 hz grid !

[@mikepxg6406]

I get my wife to talk to them.

[@FuriousMess]

I have 4 of the model before this one with the Linaeum tweeters and the next model center channel along with a Sony SW. All bought on sale at RS over two decades ago. I've had to replace the foam on all the Optimus speakers a little over 10 years ago now and they're still great little speakers. There's a cross-over mod that's supposed to be good, I just use a sw and they're fine.

[@bryanmcwhirter9945]

I still have 2 pairs of the minimus 7, one set i replaced driver and tweeter the other is stock, not alot of difference actially. A 12 db crossover would even be better but would have to be outside the enclosure but a smother response . Thankyou Tony.

[@davids4610]

Tony and his technology time machine.

[@alanarmstrong2323]

Love these speakers I have four in my system

[@strangeluck]

Huge difference after your crossover mod! But I'll keep my Minimus 7's. 😉 Always enjoy watching your work.

[@drdyna]

Just to note, on the notch filters, a much easier way to implement one in a low pass filter is to put a capacitor straight across the primary inductor in parallel, in case you ever revisit these.

[@arfer1470]

Another great video 👍. I just bought a Dayton Omnimic calibrated mic so I can have some fun modding my speakers. Perhaps you should try one or a Umik calibrated mic, it will take the guesswork out of it.

[@mattalki]

I have 6 of these speakers, and I've refoamed all of them. I've also had to refoam two center speakers from Radio Shack (Pro CS-5 and CS-3), and they've all come out on the other side just fine. I worked at Radio Shack from 1991-1996, so these came out right at the end of my tenure there. They sounded amazing for the money - they were only $300 a pair retail and paired with a little subwoofer, they sounded really decent. I always thought Radio Shack was the king of decent sounding cheap speakers. Enjoyed the video!

[@chriscarpenter243]

I worked for the shack about the same time. What state did you work in?

[@mattalki]

@@chriscarpenter243 I worked in northern Colorado, specifically Fort Collins and Loveland. It’s been awhile!

[@chriscarpenter243]

I worked in Cali. and Idaho@@mattalki

[@greggaieck4808]

Xraytonyb your utube videos are awesome I like your utube videos

[@julianrosas4992]

I have a pair of this same model speakers I bought for 6 dlls for the pair, as you show in this videos foam is ripped, exterior is in very good condition I'm trying to get a new set of speakers to switch'm out, thanks for all your advice and tips, blessings

[@ftlbaby]

Dayton Audio DC130AS-8

[@hitechrr]

I have 4 that I bought about 25 years ago. I just refoamed all 4. I also stuffed the cabinet.

[@collinwood60]

Hard to tell on a video but it did seem like the treble was better and bass not as overpowering. Nice mod for speakers that are brand new old stock still in the box. I’ve always liked Realistic equipment, especially their receivers. I have a CD player from the 80’s that still works well too.

[@rickp6731]

New Company called MC Audiotech is bringing back this Technology with their Forty-10 and TL-12 Speakers

[@Trex1268]

Pioneer HPM-100/60/40 All surrounds are rubberized cloth. Mine was made in 1976 and they're still going strong!

[@samuelnorton7012]

Do those little square super tweeters make any sound? I've had alot of hpm 100 and all would show open circuit on that tweeter. Looks like a piece of foil with terminals.

[@PoppinWheeliez]

I bought a NOS in box minimus 7. Hooked them up and they sounded fantastic. Yamaha NS cloth surrounds as well. Why not plug the ports off with wine corks? Refoaming speakers is very easy if you employ the use of a 9v battery and use Alieens tacky glue. If the dustcovers are pushed in then may as well shim them.

[@PAINFOOL13]

I had 2 pair of these one pair like these then the larger ones .liked em . Ended up giving them away as I had moved on to a 7.2 system. Cool vid .thanks for the memories.

[@len9518]

"simply Speakers" is also a terrific source for refoaming materials...inexpensive, with video instructions.

[@davidhamm5626]

Yes, I use them all of the time.

[@PCBWay]

Impressive!!

[@xraytonyb]

Thank you!

[@hitechrr]

They are the first gen model. I have a set of first gen and a set of second. The second gen has one port, and the top has no screws. I had to re-foam all 4. I bought mine new on clearance for $50 each sometime in the 90's. I still use them today. I have a 12" sub-woofer for base.

[@hitechrr]

They are good down to about 80Hz before you let the subwoofer take over.

[@dannyalvens5418]

@user-xz5pz7hk8k Well,His statement is right if you think about it. Do you go bass or base fishing? The bottom of something is the base is it not.. I never understood why the manufacturers , scientists and even the engineers got it backwards...

[@hugh007]

Have you ever checked the peak resonance of a speaker when new and after break in? I have changed a few ported boxes to sealed and there is less 'boom', but with enough power to overcome the reduced efficiency, they sound much smoother, with extended, clean lower response. Thanks.

[@greggaieck4808]

Xraytonyb when you work a radio shack. In the 90s remember Realistic Nova 34 speakers

[@BrooksBollman]

Would your crossover mod help with the OEM woofer, or should s different value part be used? Thanks for the interesting video.

[@greggaieck4808]

Xraytonyb your Realistic Optimus por LX5 speakers is cool

[@XtremeKremaTor]

Lacking in foam is to partially direct the wave through the bass reflex ports. If there was a good padding, too little air would go through, if not at all, the velocity of air would make a noise leaving the port. Balancing act I suppose

[@ericschulze5641]

Line the ports with self adhesive felt & put a piece of nylon stocking over the end of the ports with a rubber band off some broccoli it will fix the port noise you can prove this works by blowing through a plastic tube & then line it with self adhesive felt the noise goes away

[@MickeyMishra]

I only wanted these as they looked cool and the tweeter. That Low Crossover point has lead to many blown out tweeters.

[@jimharmon3404]

Hi Tony, Since we cant "see" the changes you made in the sound could you put together a video "Speakers for Dummies" and self identified "experts" ? I would like to see a spectrum analyzer display of the voltages across the tweeters and woofers so we can see what you are explaining. Thanks for all the work you put into creating these entertaining ( electronics is fun) and informative videos. You have me thinking about my Marantz Imperial 7 Speakers now.

[@tmmtmm]

Ported boxes having lower internal pressure is a myth. At the tuning frequency the ports are sucking in air while the speaker cone is moving backwards, so they are working together to create an even higher internal pressure. Above tuning it's effectively a sealed box, below tuning it's an open/leaky box.

[@adaboy4z]

Im going to try this mod. Thanks!

[@petertimp5416]

Have you tried blocking off supports and also adding a .15-.18 micro Henry coil to ground for the Tweeter

[@orchardroadstudio]

So funny to see this I always wanted a pair of those

[@markweikle5645]

I have done the replacement mod on the Minimus 11 and Minimus 7. The 7s are wonderful even stock, but can be improved with a replacement with a lower low end. The 11s I bought new 1/2 price at clearance in the 90s and had the RCA branding and "pro", which were ported. I've always been disappointed with them and thought maybe that would help. I just put the poor quality down to the port.

[@markweikle5645]

Now that I see the 4.7 uF cap mod it makes so much sense! now I'm going to have to dig then out and open them up again.

[@queputaleche]

Hi Tony! Correctme if I'm wrong, If you see the impedance curve, you'll note that the 60Hz impedance is closer to 20 ohms as is near the resonance of a woofer of that size. How will this affect the math for the voltage you use for the burn in? Edit: another one: what about having phase reversed by using one driver on a 2nd order filter?

[@SDsailor7]

So would adding some foam to that speaker improve the sound?

[@mlbabineaux]

HAHA... I had some of those a long time ago. I worked at Radio Shack, too, Tony.

[@davidgriffin79]

33:33 It would have been nice to hear something with male/female vocals, as the frequency range of the human voice is slap bang in the "midrange" and something we are all familiar with.

[@wobblinwheel]

I noticed you have the speakers really close together. Did you make sure the woofers are still "in phase"? I'm sure you did, but I didn't see you plug the wires back into the woofers. Just checking...I know, dumb question...🤪

[@Dutchamp]

Boxes looks OK. But that coil a ferrite type? Brrrr cheesy a desent aircoil is better and the wiring is not so good too. But it shall be a budget priced speaker. We'll oke jobs done👍😉 your tweak did a lot of good. Even here on KZbin it is noticeable I hear more highs en smoother mids and better bass response. You did a nice job 👏

[@melbahouse5743]

to stop the chuffing sound try flaring the ports inside the cabinet .

[@koprcord5338]

Don't know, mine sound great, granted I do cross them over at 80hz with my receiver but the amount of sound they reproduce is nice. I do believe replacing the original 6ohm speaker and replacing with 8ohm will change the sound. Also there is ferrofluid in the tweeters which I don't believe can be serviced. There is a video out there showing a teardown and the ferrofluid. Could be dried up causing the loss of highs. Also the newer ones have a single flared port and branded rca sold at rs but exact same drivers.

[@AuribusAcoustics]

A very small amount of paint thinner between the ribbons should bring it back to spec

[@Jammerk40]

Still have mine and never had to replace the surrounds because mine has rubber surrounds! I think mine are the LX7

[@conchobar]

Just build a new front baffle out of wood. This allows much greater variety of midbass drivers to use. There's also a capacitor inside the tweeter unit that many in the past claimed should be removed. I should buy a pair and make a video measuring it.

[@dannyalvens5418]

I did that years ago and got rid of the port,they sounded better..Then I ended up making a taller front baffle and changed out the tweeters to a pair of ess Heil air motions So the highs would have more directionality..

[@craigpoyner1221]

Do you recall the manufacturer and specifications of the 4.7 microfarad capacitor that you used

[@mr.m325]

weird...they sound exactly like the speakers i'm playing the video thru

[@FOXBODYCENTRAL]

Hello need some help, my new sx-1250 showed up . Found awr-1070 wire wound resister and thermo temp burned . What’s a good replacement for these? Seems the resistor has a bracket to mount it to chassis ground ? Just support or a ground? Any help would be great!

[@danielsaturnino5715]

I wish I knew where to get those refoam kits at portugal. I have a pair of 12 inch celestion woofers, I believe from the 70's with no foam at all. I did send an email to celestion but got no answer.

[@andymouse]

It would have been nice if you could measure the response and other characteristics and see a Before/After as listening after you tube has had its way with it dosent demo much, but great information as always....cheers,

[@xraytonyb]

I actually tried (using the zoom mic and Audacity's frequency analysis), but it didn't work out that well. I really need to get a proper mic and software to be able to properly test the linearity of speakers. To my poor ears (for what it's worth) it sounds much better after the mods. Thanks for the comment!

[@ABC-rh7zc]

The size of the speaker isn;t the issue. It's other parameters such as resonant frequency which matter.

[@jeffadams5510]

Way more gooder with the mods and that woofer. Now, refoam the originals and see what that gets ya :)

[@vcp93]

Surround decay on older speakers is not uncommon. Replacing surrounds is not that difficult. If, for whatever reason, you like this speaker, I would definitely not replace the driver if it is still working. Just replacing a driver in a speaker with a driver of similar size and spec may not yield the best results. With a speaker like this it probably wouldn't be that big of a deal. Good bookshelf speakers are not that expensive these days. You have better options. Thanks again for all the great videos. I have learned so much. Cheers.

[@mikepxg6406]

I always replace drivers.

[@vcp93]

@@mikepxg6406 to each his own. Unless you are replacing them with the same driver, you could be degrading the sound profile of the speaker. Speakers of this type (as I mentioned) probably won't make any difference.

[@BASSBOYDecepticon]

ehhh. most of these drivers are of such poor quality any replacement would be an improvement.

[@seanobrien7169]

As Tony mentions, the enclosure is most likely too small for the woofer anyway, so I doubt these were really engineered as much as just slapped together for maximum sales potential. That is not a knock against Radio Shack, I am actually a fan of their stuff, their high end stuff was pretty decent up through the eighties until they just went to hell and eventually became a cell phone outlet...

[@vcp93]

@@BASSBOYDecepticon with this speaker, you're probably right. 👍

[@gordthor5351]

I plug the ports on all my speakers, having only one bloated resonant point. You have three, so why not just plugging the ports?

[@paulturner3553]

I have the LX5 11 speakers which I assume were the later same as LX5's, but improved. Optimus speakers were being closed-out when I bought mine at 50% of regular price. I use mine as satellite speakers with 15" 3-way Fisher speakers connected to a passive 12" Optimus sub-woofer. Lots of speakers on hand to experiment with. I have a pair of Infinity speakers with 12" bass which is highly rated. Getting to the age where changing speakers around is burdensome, and a crap-shoot for not much better/not much worse sound quality. I'm not a single guy, so I don't want to irritate my better half with stuff all over the living room.

[@johnnytoobad7785]

It would have been helpful if you elaborated a bit on just how you determined the EXACT value for that 4.7uf shunt capacitor. I know 2nd order filter equations may imply some "knarley math" but we're all "big boys" here..

[@chrisharper2658]

I see your using a Vessel screwdriver. Is that because it may be a JIS type?

[@jetpack5]

Is there a how to for replacing the ferrofluid in the ribbon tweeters

[@seanobrien7169]

Yeah, I can still hear trhe difference even with KZbin. Pre-mod they were pretty muddy, a lot crisper with the cap across the woofer. Still not awesome, but I mean, look at what they are. Sound pretty decent for little mini bookshelf speakers.

[@jubemarsh2202]

We can't polish a turd but I think you just did 🤙 Thanks for your awesome content 🇺🇸