Hi-Vi L5-8R 5" Woven Kevlar Cone Woofer
Price:
$33.40
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Overview
Radio Shack Optimus and LX5 Replacement Woofer
Hi-Vi Research L5-8R Woven Kevlar Cone Woofer
- Rigid woven kevlar cone
- Long throw linear excursion design
- Hi-Vi Symmetric Motor Drive (SMD) technology
- Shielded magnet system
- Rubber surround
- Frequency response 60Hz to 5kHz
- Works well in both sealed and ported boxes
- Rare and unique shape and size
Also drop in replacement for Paradigm, Boston Acoustics HD5, PSB Alpha B1, EAW UB12S, Advent Mini, Polk Monitor 50, DC130A-8, DC130AS-8, ADS L300C, among many others with this hard to find "pincusion" shaped frame.
Chances are if your driver measures about 5-13/16" diagonally, 5-3/16" across the frame, and your throughhole is 4-19/32" or a little bigger, then this is what you have been looking for!
If your woofer is rear mounted on the front baffle, you need at least a 116mm hole opening in the baffle so the woofer rubber surround can move freely. That is about 4-5/8".
We receive constant feedback from our customers on how good these sound as a replacement driver. They fit AND are an upgrade!!
For the Optimus Pro-LX5II, the woofer is rear mounted and the opening is not large enough, the woofer surround will slightly rub against the opening edge. A customer was able to make this work by adding a 1/4" gasket to the front of the woofer to have it sit further back from the baffle. You could try using foam gasket tape to create this clearance.
For the Optimus Pro 77, the existing 0.4mH inductor on the crossover stands too tall and impacts the L5-8R magnet. You would need to either change to a flatter inductor or move the inductor to another location.
Does not fit the rare RCA center channel 40-5038.
Possible alignments:
0.3 cubic feet sealed with 25% polyfill stuffing for a 3dB down of 77Hz.
0.4 cubic feet sealed with 25% polyfill stuffing for a 3dB down of 75Hz.
0.4 cubic feet sealed with 25% polyfill stuffing for a 3dB down of 76Hz.
As you can see, this woofer is going to perform well in pretty much any sealed box.




Perfect for my Optimus Pro LX5
Reviewed by Dsm90awd on 01/16/2026
I've gotten nostalgic now in my 50s and my old pair of Radio Shack Optimus Pro LX5s have been with me for years. With the kids off to college I finally had my basement free of XBOX and wanted to rebuld a Movie room. Unfortunately these speakers foam surrounds were no more. I thought about a reform kit but the price and feedback of these replacement drivers sounded enticing. Flash forward.. these fit perfectly and have 3x the magnet as the old drivers. Sound is much better. Definitely keep Madisound in mind for future upgrades.
Verified Purchase
Perfect drop-in replacement, and they sound great!
Reviewed by dharmabumstead on 12/07/2025
I've had a pair of Optimus LX5 Pros collecting dust in the closet for about 30 years now. I pulled them out recently and discovered that the speaker foam was toast, so I took a chance and ordered a pair of Hi-Vi L5-8R replacement speakers.
Happily, this turned out to be a great choice! It took about 15 minutes to yank the old speakers and drop these in. Paired them up with an old Sonos Amp I keep around to drive our deck speakers, put on the title track of Donald Fagen's Morph The Cat, and was amazed by the improved bass response (that did not, contrary to what I saw in a YouTube video, "overwhelm" the tweeters). To double check this, I played Stanley Jordan's version of "Freddie The Freeloader" (off his Magic Touch LP), to hear how the L5-8Rs played with the OG Linaeum tweeters, and was again amazed...the acoustic bass was rich and full, but it balanced well with the delicate cymbal work.
Will these old LX-5s replace my Wharfedales? No. But after dropping these L5-8Rs into them, I'm super happy with them for what they are. Money well spent!
Happily, this turned out to be a great choice! It took about 15 minutes to yank the old speakers and drop these in. Paired them up with an old Sonos Amp I keep around to drive our deck speakers, put on the title track of Donald Fagen's Morph The Cat, and was amazed by the improved bass response (that did not, contrary to what I saw in a YouTube video, "overwhelm" the tweeters). To double check this, I played Stanley Jordan's version of "Freddie The Freeloader" (off his Magic Touch LP), to hear how the L5-8Rs played with the OG Linaeum tweeters, and was again amazed...the acoustic bass was rich and full, but it balanced well with the delicate cymbal work.
Will these old LX-5s replace my Wharfedales? No. But after dropping these L5-8Rs into them, I'm super happy with them for what they are. Money well spent!
LX5 Pro drop-in replacement
Reviewed by soundslikeste on 11/02/2025
I picked up some Genexxa LX5 Pros cheaply & despite the price being bumped up by shipping to the UK, these drivers have been worth every penny! Just create distance between the driver surround & cabinet with extra gasket to allow the cone to move freely.
FYI, I've removed the tweeter grill completely & refit the tweeter on top of the cabinet. The tweeter polarity was also reversed, the sides lined with Dynamat & 1" acoustic foam added to the cabinet interior. It's a great transformation.
FYI, I've removed the tweeter grill completely & refit the tweeter on top of the cabinet. The tweeter polarity was also reversed, the sides lined with Dynamat & 1" acoustic foam added to the cabinet interior. It's a great transformation.
Verified Purchase
Perfect fit for Vintage RCA 40-5037
Reviewed by jed@carrollcustomdesigns.com on 09/13/2025
I don't often write reviews unless I am unhappy with a product. In this case I am so happy with this product that I had to write a review. These fit nearly perfectly in my Vintage RCA/LINAEUM speakers I rescued out of the trash. Less than $100 and I now have a amazing sounding pair of bookshelf speakers with dipole tweeters. The original woofers were slightly smaller and the surrounds had left the chat but these dropped right in and sound as good as I could have ever expected. The original drivers were 6 ohm and these are 8 ohm but almost no loss in sound after replacing them. Big bonus that they are rubber now instead of foam and should last forever.
Verified Purchase
Uneventful Replacement for my Pro-LX550
Reviewed by dgduerr on 08/24/2023
Beautiful , absolutely perfect fit!!! Purchased these new from RS, with the RCA badging (Cat # 40-5037), and when the foam surrounds failed last year my heart dropped! Yes, I have refoamed before, but who want to go through the hassle? Madisound Speaker Store to the rescue. Thanks for bringing this product to the market.
Verified Purchase
perfect fit for Polk T15
Reviewed by joerodit@gmail.com on 02/03/2023
I like the look of the speaker and it has a good WAF. However, the drivers on this speaker are mediocre at best especially the woofer. Boomy with awful midrange. These are a great upgrade and it dropped in w/o any modifications at all. They have great imaging a male and female vocals are super clear. Went from veiled to very pleasant. More upgrades coming!
Excellent Upgrade
Reviewed by PhotoGreg on 11/17/2022
These woofers fit perfectly in the Optimus L5's as stated in other reviews. The sound quality is dramatically better as these exhibit better low-end response and tonal clarity.
I did modify the built in cross over to address some midrange peaks.
Overall, I am super impressed at the new life brought to my L5's.
I did modify the built in cross over to address some midrange peaks.
Overall, I am super impressed at the new life brought to my L5's.
Verified Purchase
works great.
Reviewed by saggman54 on 07/10/2022
using in Realistio Optimus pro lx5 fit's with no modifications. tried some other ones first and the mounting gasket on those made the speakers sit deeper in the cabinet and require longer screws.
also like that these have the rubber surrounds instead of foam.
also like that these have the rubber surrounds instead of foam.
Good as Advertised
Reviewed by tommourgos on 06/22/2021
All these reviews are right. The speakers fit perfectly and the surrounds are much more durable than the originals. I'm using them in RCA (Radio Shack) Cat. #40-5037.
Handled Perfectly
Reviewed by sm935@bellsouth.net on 04/26/2021
Ordered 4 of the 5" Optimus LXII replacement woofers, one worked intermittently and was going to return it. They just said keep it and we'll send you a new one, which is all I wanted. Great customer service! And the new woofers actually do sound quite a bit more solid than the originals, built better too, better speaker surround material. After repairing one pair of these (I have 3 pairs), I would HIGHLY recommend that you buy these replacement speakers instead. Much less hassle and mess (glue smell is enough to dissuade) and much better sound. Only a little more than the kits, and the new speakers will last longer than the old rebuilds. These will work great in Optimus Pro-LX, Optimus Pro-LXII, and RCA Linaem 50-4007 made for Radio Shack. (Have 1 pair of each).
Verified Purchase
Good LX-5 replacement
Reviewed by vidgamer on 12/31/2017
These seem like a great value. Very clear sound for not a lot of cash. I realized that the foam on my LX-5 woofers was starting to tear, but at these prices, it's better to upgrade the woofer than to try to refoam.
The old woofers sounded a bit "muffled" compared to these. I measured a bit more upper-midrange with the new ones, but they do seem more clear. Bass is especially more detailed. Volume level seems to be about the same, which means that the tweeter is still overpowered a bit, but if you were OK with it before, it'll still be OK, only the mids will be more clear and with better bass. The tweeters seem to be a bit more audible, but they are still recessed a bit. Stock speakers are very boomy in the mid-bass; I stuffed the cabinets with some polyfill to combat that.
These were a perfect fit for the LX-5. Opening the front of the LX-5 is a bit tricky, but tips posted on AudioKarma were helpful. This is not a difficult job.
The old woofers sounded a bit "muffled" compared to these. I measured a bit more upper-midrange with the new ones, but they do seem more clear. Bass is especially more detailed. Volume level seems to be about the same, which means that the tweeter is still overpowered a bit, but if you were OK with it before, it'll still be OK, only the mids will be more clear and with better bass. The tweeters seem to be a bit more audible, but they are still recessed a bit. Stock speakers are very boomy in the mid-bass; I stuffed the cabinets with some polyfill to combat that.
These were a perfect fit for the LX-5. Opening the front of the LX-5 is a bit tricky, but tips posted on AudioKarma were helpful. This is not a difficult job.
Excellent Value X 6
Reviewed by Yujibob on 07/24/2017
I had 8 RCA Optimus Pro LX 5 speakers with deteriorating surrounds and I read this speaker was a direct replacement. It's been several weeks now listening to my rebuilt speakers and they never sounded this good even when new. This is a fantastic speaker for the price and it's shielded just like the originals. The bass is far superior and even the mid-range sounds improved which is saying something for a two way compact enclosure. The replacement was effortless. I suggest you do not even bother with the free gaskets they supply. My only complaint was I only bought 6 instead of 8 because I really only needed 6. Shipping over $100.00 is free so this was an incredible bargain and now I wish I had purchased the extra 2. Fantastic price, fantastic sound and an effortless replacement.
Optimus Pro LX-5 Replacement Woofer
Reviewed by willo on 06/21/2017
This speaker driver is a perfect replacement for Optimus LX-5 Radio Shack speaker. Fits perfectly with no modification. The best part is that it sounds fantastic... better than the original. Bass is tighter and a little deeper, not to mention that you can play at a higher volume level with no distortion. The price? Only 20.00 bucks. You've got to be kidding me. Highly recommended!
Verified Purchase
Replacement for Paradigm Alpha B1
Reviewed by dl2341 on 07/21/2016
This is a drop in replacement for Alpha B1 to fix the weakness in the speaker. The upper midrange of the OEM woofer is lacking, and this woofer is clear and detailed through the operating range, just like the frequency response is shown in the chart. From 55-3000 the output is almost a straight line, it's that flat!!
Perfect fit for Optimus Pro LX-5
Reviewed by allanjay1125 on 01/11/2016
This is a great replacement for the Pro LX-5 woofer. They sound much better than the original woofers and literally are a perfect fit. Audio Karma has great instructions on how to replace the woofer. It only took 20 minutes to replace the pair.
Optimus PRO LX5 Replacement
Reviewed by Elwood on 06/04/2015
Drop-in replacement for original woofers in a pair of LX-5 MkI.
At $20 ea. only about $10 per speaker more than a kit to replace the foam surrounds on the originals - and these are far superior to the OEM part.
Nicely packaged and included a new gasket for the baffle. More than I expected at this price point. Exceptionally fast shipping by Madisound.
Very pleased with the sound.
At $20 ea. only about $10 per speaker more than a kit to replace the foam surrounds on the originals - and these are far superior to the OEM part.
Nicely packaged and included a new gasket for the baffle. More than I expected at this price point. Exceptionally fast shipping by Madisound.
Very pleased with the sound.
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