Polk Audio Monitor 7s Restoration Journey

[jrtmouse]

I recently purchased a set of Polk Monitor 7Bs for $40. I realize now I knew nothing about these gems at the time. They've been quite the journey. One of them was complete with what I believe was the original Peerless tweeter (M7, 55141883) fitting perfectly into the tweeter space. The other had some sort of BOSE mid and the SL2000 as the tweeter, which did not physically fit perfectly into the tweeter space. I eventually found an exact matching mid I needed, MW6500, to replace the Bose mid. I originally noticed one of the speakers didn't sound as "loud" as the other, a bit muffled. Through a lot of coaching from ChatGPT, we managed to test all of the parts, reheating every solder point on the crossovers to rule out any cold solders, checking every wire, checking all parts with a volt meter on the crossovers to rule out any issues with capacitors, et al. While they sounded fine enough, I knew I wanted them to sound as good as they could so Chat lead me to believe the RD0-194s would be the tweeter replacements I needed. After waiting nearly two months for them to be back in stock, I ordered them. After further research, I learned the RD0s really weren't the correct replacements. They didn't sound great after installation, so I replaced them with the originally (to me) installed Peerless/SL2000 set. Even though they're not matched, this combo sounds much better than the RD0s. Realizing the crossovers are definitely the original Peerless compatible one, I'm trying to decide how to proceed. I love my audio experience but this speaker journey has been a roller coaster.
Do I overhaul the crossovers to match the RD0s?
Considering Peerless tweeters are few and far between, is there a modern replacement much like the RD0s from Midwest that's close to a good replacement and if there was, I'd buy a set to match.
Is there even the slightest possibility I'd find an old Peerless to match? I'm exhausted and frustrated from these speaker overhauls.

 

[Dswankey]

The 7B's should originally of had either the Peerless or SL-1000 tweeters as seen below



The SL-2000 possibly ended up in your speaker as a replacement by someone else



The Polk Audio RD0-194 tweeter was/is a common direct replacement for the SL-2000

....Is there even the slightest possibility I'd find an old Peerless to match?

Original Peerless show up time to time on sites such as the Bay, so be patient and you should be able to find one.

We like pictures so if you can post pictures of the tweeters and tweeter baffles in their current state I'm sure a lot of folks here can help you out

 

[StimpyWan]

There are several Peerless and Polk SL1000 tweeters on eBay (none mine). I assume they'd help. But it gets expensive piecing speakers back together like this.

Good luck...!

 

[Lavane]

I have a lair of 7's with the Peerless tweeters. They do sound nice.
I did replace the SL-2000's in one of rhe pairs of Monitor 10's I have with the
RDO-194's and it was a deffenet improvement. I can see where they may not have sounded right in the OP's 7's if they originally had the Peerless or
SL-1000's the RDO's would sound a bit off since the crossovers are going to be a bit different. I dought the RDO-194's would sound better than the Peerless tweeters, but probably would over the SL-1000's with a crossover tweek.

 

[jrtmouse]

I paid $40 for the set. There's water damage to the bottom of the one, which lead to some slight swelling at the bottom. However, from the inside, it's sealed very well. It was also missing a wire post but I've replaced them all with new posts.
Speaker A (left) looks and sounds terrific, with what appears to be a Peerless tweeter.
Speaker B (right) had a Bose driver and what appears to be a SL2000, as it sits atop the baffle.
After some patience and searching, I was able to find a matching driver (MW6500) to replace the Bose.
The images towards the bottom are current pics. Like I mentioned before, I tried the RD0-194s and didn't care for how they sounded given the current state of crossovers, built for Peerless. Their current status sounds better than that with the RD0s. Ideally, I'd probably want to find a matching Peerless.

These poor little guys have been through a lot but I feel I'm nearly there if I can find a tweeter.

 

[Dswankey]

So it looks to me that you have a pair of early model 7B's that originally came with a set of Peerless tweeters.

As mentioned you can tell from the pics that the SL-2000 does not fit in the original enclosure.

If it were me I would put them to the side until you can find an original Peerless also the current Peerless is installed upside down

 

[knotscott]

What to do with the crossovers is always a judgement call based on whether you want them to be as close to original as possible, or whether you want to upgrade any of the parts. Not trying to belittle the speakers in any way, but I'd view them as a fairly decent, but pedestrian speaker of the era that was built to a strict price point....not a ground breaking or elite speaker. In situations like these, I've tended to upgrade caps, wires, connectors, sometimes resistors and chokes, and address cabinet resonance where possible. It can definitely change the sound a bit, but is not radical modification, and is usually an upgrade IMO while still maintaining most of the character of the speaker. My 2 cents.

Keep us posted!

 

[Lavane]

So it looks to me that you have a pair of early model 7B's that originally came with a set of Peerless tweeters.

As mentioned you can tell from the pics that the SL-2000 does not fit in the original enclosure.

If it were me I would put them to the side until you can find an original Peerless also the current Peerless is installed upside down

And two screws missing. You don't want any air leaks in this type of speaker with passive radiators. If you gently press down on each side of the midbass driver it should come back up kind slowly. Also in the picture posted by the OP I don't see a hole in the center of the Peerless tweeter. Maybe I just canteen it in that picture.
Posting a WTB add in bartertown looking for a Peerless tweeter might be helpful too.

 

[onanysunday]

I'd hold out for a match on the original Peerless tweeter (for the mismatched right side) according to your photos. Also, even if you tested caps somehow with ChatGPT, it's likely you didn't test them fully which could indicate reduced performance even if you thought they were fine, eg. leakage, ESR, ESL. Recapping them would bring them back closer to original performance with the original Peerless tweeters and would be the best move in my opinion. Or, if you prefer, it appears Midwest Speaker sells a drop-in, direct replacement for it. I'd probably order two so they match.

MW Audio MT-4115: 1″ Dome Tweeter | Midwest Speaker Repair

 

[Lavane]

I'd hold out for a match on the original Peerless tweeter (for the mismatched right side) according to your photos. Also, even if you tested caps somehow with ChatGPT, it's likely you didn't test them fully which could indicate reduced performance even if you thought they were fine, eg. leakage, ESR, ESL. Recapping them would bring them back closer to original performance with the original Peerless tweeters and would be the best move in my opinion. Or, if you prefer, it appears Midwest Speaker sells a drop-in, direct replacement for it. I'd probably order two so they match.

MW Audio MT-4115: 1″ Dome Tweeter | Midwest Speaker Repair

View attachment 3852494

Nice. I hadn't seen those at Midwast when I was looking at replacing the SL-2000's for my 10's. I agree, if finding an original isn't panning out, just buy two those these. Midwest is producing the Polk labled drivers licensed my Polk if I remember right, so I would expect these replacements for the Peerless tweeters would be a good choise for replacement.

 

[onanysunday]

I was very happy with the RD0198's I purchased from them for my Polk SDA-2B. I "TL modded" them with recapped/ upgraded crossovers and improved tweeters.

 

[jrtmouse]

So it looks to me that you have a pair of early model 7B's that originally came with a set of Peerless tweeters.

As mentioned you can tell from the pics that the SL-2000 does not fit in the original enclosure.

If it were me I would put them to the side until you can find an original Peerless also the current Peerless is installed upside down

Yes, I realize it's upside down, LOL. It was late the night I was frustrated and stressed about my $135 RD0s and ripped them out to replace the original back in temporarily until I figure out how to move forward. The speakers are in an awkward location and I just wanted to put them back into a state of pleasant listening state. Once I have a complete set of tweeters, I'll reset it as appropriate.

 

[Lavane]

Yes, I realize it's upside down, LOL. It was late the night I was frustrated and stressed about my $135 RD0s and ripped them out to replace the original back in temporarily until I figure out how to move forward. The speakers are in an awkward location and I just wanted to put them back into a state of pleasant listening state. Once I have a complete set of tweeters, I'll reset it as appropriate.

Oh well. Now you have a set of RDO-194's for when you find a pair of Monitor 10's.