I picked up a pair of Rhino Mk IV speakers from an estate sale last month in Houston. They were cosmetically in great shape but the foams around the 10.5in woofers were completely decomposed and one of the 4in drivers was dead. After a little testing, the second 4in driver stopped working. I decided to restore them based on what I saw in this thread and a couple others.
ChatGPT identified the tweeter as the Phillips AD 0160/T8 (8ohm, 90-92 db sensitivity, 1500 Hz to 22000 Hz frequency response. It was not able to identify the woofer or midrange driver.
I removed all the staples at the bottom of the cabinet and pulled the speaker cover all the way up over the top to expose the drivers. I found a refoam kit (Part # 260-968 on Parts Express) for the 10.5in woofer that was meant for a Cerwin Vega speaker, but it fit this one pretty well.
I ordered four different midrange drivers to compare and test out. Most of them didn't quite fill the original cutout so I also ordered a couple of MDF adapters to ensure a proper seal. Here are the speakers along with my impressions of them.
FaitalPRO 4FE32: Very revealing and an outstanding speaker, but it was a touch shouty. This speaker's sensitivity was probably a little too high because it overpowered the tweeter and woofer.
LaVoce FSF041.00: So similar to the FaitalPRO that I never even put it in the cabinet.
Beyma 4FR40: All the revealing nature of the FaitalPRO with a touch more smoothness. On stand-alone performance, this one was my favorite. The only reason I didn't choose it was because the next speaker just integrated so beautifully with the tweeter and woofer.
GRS 4FR-8: This one took me by surprise. It doesn't have anywhere near the frequency response of the other speakers in this list, which all top out at 17khz or higher. The GRS tops out at 10khz, but that's probably what made it integrate so nicely with the rest of the cabinet. Oddly enough this was the cheapest speaker by a fair margin ($14/each compared to $30-50/each for the rest).
There were two capacitors in each cabinet, one (Temple 203, 100uf, 50VNP) attached to the woofer and a second (Mallory, 2mf, 50VNP) attached to the crossover. There was also an inductor mounted inside the cabinet, but I couldn't get a clear look at it. I replaced the two capacitors with Dayton Audio PMPC capacitors (10uf 250V and 2uf 250V). The crossover was a little challenging to access because it was mounted inside the cabinet between the tweeter and midrange driver with all of the incoming wire stapled to the cabinet walls. I stuck my phone and a flashlight in the case and use it to look up toward the speaker cutouts. I then used a small flathead screwdriver to remove the stables. Then I unscrewed the crossover and was able to feed it out the cutout for the midrange driver. The wiring and soldering looked pretty shoddy but I could only do marginally better with my skill level. Even so, I desoldered all connections and remounted everything.
I'm VERY pleased with the final result. The sounds is outstanding. I only have my Ohm Walsh 2 as a point of comparison and some Tannoy Stirling III Special Editions I heard at a local audio store. These are more revealing and fun sounding than my Ohm Walsh 2s. Where my Ohms excel at jazz, acoustic and vocals; these are able to cover more genres and can really jam. I still love my Ohms but the Rhinos make me realize I desperately need to add a couple of subwoofers to that setup. The Rhino is close in character to the Tannoy but not as refined. Even so, those are $12k speakers so that's impressive in my book.
I have the speakers setup in my bedroom, driven by an NAD C326BEE integrated amp and a WiiM mini streamer. I hooked them up in my main listening space to my McIntosh MC2150 and a DIY tube preamp I built. They sounded great there too but I didn't feel like they benefitted from the higher end amp as much as my Ohm Walsh 2s do.
When I get around to it I'll record a sound test video and add to the thread.
