Monitor 5s...different cross overs?

codycatalist · February 2016

Was packing up my monitor 5s to head to a friend's to listen and I noticed they were different weights. Curious I opened the radiators and saw different cross overs. Can anyone tell me some more information?

codycatalist · February 2016

smglbrth · February 2016

All I can tell you is that I am in the process of "rebuilding" my 8t's, including the crossovers and mine look the same as yours, well, more doodads on the boards of course. One is the older style we are all used to seeing and one is the newer, like your top pic in the 2nd post. It's gonna be hell for me to fit any type of capacitors on that board. I am not looking forward to it.

Far as I know Polk changed things as they went along and used what they had leftover. The newer looking one could be a replacement crossover as well, maybe.

So, ya, your not alone...

skrol · February 2016

The top one looks to be newer. They look like they are electrically similar with the same component count and types, though I can't read all the component values. Are you the original owner?

codycatalist · February 2016

Haha just making sure I'm not the only one! Skrol, I am not just picked them up for a cool $30 a couple weeks ago. Been enjoying the sound too much to focus on imperfections but ready to get to making these puppies sound their best. I have a blown tweeter in one of these monitors so I figured I'll replace the clear sl2000 with the 194 head nothing but good things. I also have some rta11tl towers that have some blown components I want to fix as well.

skrol · February 2016

I am the original owner of my RTA11TL's and did the upgrades a few years ago. Since then I got a pair of LSi15's but still can't part with the RTA11TL's. I am glad I have them in my basement system doing HT and music duty.

In your RTA11TL's, check for bad solder connections. On one of my XO's, where the mylar cap is bypassed with an electrolytic on mine, it was not even soldered.

codycatalist · February 2016

Will do, having my friend bring the RTAs down today so I can start working on them. Nothing like good polk audio IMO.

xschop · February 2016

I found that the Early 5Jr didn't have boards and the later ones are supposed to.

I have another question. What is the measurement of the MDF between the Passive Radiator and the driver in your pics? Does the baffle have flex in it?

codycatalist · February 2016

I'll take some measurements in the next couple days and let you know. Currently bed ridden with the flu, can't even enjoy my monitor 5s right now. =(

xschop · February 2016

Ugh, sorry to hear that. Get well. Music heals, crank em up anyways.

codycatalist · February 2016

Finally back! No flex in the baffle and about 1.4 inches from PR mounting to 6.5 driver mounts.

I have some drivers with holes in the rubber. Until I can get the money to replace 4 6510s I was thinking of trying to repair them. Any words of advice or glues that might help?

codycatalist · February 2016

Repairs are for rta11tls not my monitor 5s.

Polkaguy58 · February 2016

Just for jollies tonight, I tried sticking a set of Monitor 5 crossovers into one of my pair of Jr's.
I kind of like it, much more mellow and none of that nasal honk the stock pair has.
Oddly enough, they offset eachother nicely when run in tandem.

xschop · February 2016

To PG58... Doesn't the Monitor 5 crossover cut out 60Hz and below to the MW? That's what I gather from reading here.

And to Cody, I have used a vulcanizing butyl type bicycle tire repair glue on a few butyl surrounds with excellent results.

Polkaguy58 · February 2016

I haven't a clue where the crossover points are on the any of my Polks.
I'd love to see a chart of not only the crossover points, but the frequency roll off of the woofers and tweeters when running straight out.
I also would like to know why Polk used less electronics in the Jr's as opposed to the 5's, seeing they both employ the same drivers.
Hey, I'm no audio engineer by a long shot............but I am curious.
I will say that I do like the Jr's combined with the Monitor 5 x-overs.
They sit back a bit more in the soundstage and are not so in your face like the stock Jr's, however when you combine the two, they work well together.

Polkaguy58 · February 2016

Well now, this post might just get me booted out or sent to the hall of shame for heresy, but here goes...................
As I mentioned in the above post, I tried switching a pair of Monitor 5 crossovers into a pair of my 5 Jr's and liked the outcome, which was a lot less midrange honk.
What I didn't do until just now, was to listen to the Monitor 5's with the Jr's crossovers.
It had the exact opposite effect and added mids to the 5's, which I thought were a little on the darker side in their stock form.
The obvious next move was to try them all together.............and it only got better !
I'm a happy camper now and haven't even gotten to sealing up the cabinets and swapping new caps in yet !
Let the stoning begin.

xschop · February 2016

Was going to suggest that. That's after I thought about asking you to switch the tweeter polarity originally.

We need to collaborate on a 1-off frankenpolk.

codycatalist · February 2016

xschop wrote: »

And to Cody, I have used a vulcanizing butyl type bicycle tire repair glue on a few butyl surrounds with excellent results.

Yeah I poked around the forums and found someone who used air mattress adhesive. Picked up a bottle of "Air Stop" applied it, let it cure and got the drivers working again. Bad news was I found 2 blown coils in the drivers. Good news I had enough drivers to test the speakers crossovers.

Polkaguy58 · February 2016

I'll tell you one other crazy idea I've been thinking of lately and that is to score a couple of Monitor 10 crossovers and try running two active woofers in the Jr's..................."Stop him he's gone mad" ! (heh heh)

codycatalist · February 2016

Polkaguy58 wrote: »

I'll tell you one other crazy idea I've been thinking of lately and that is to score a couple of Monitor 10 crossovers and try running two active woofers in the Jr's..................."Stop him he's gone mad" ! (heh heh)

So one 6.5 one 8inch active drivers?

He is crazy but so crazy it just might be genius!

xschop · February 2016

In a 5jr+ the PR can be replaced with an active driver physically..... do it!

I am thinking the old Monitor 5 with dual 6.5" mid drivers facilitated via adapter plate on the PR and SL5000 tweet. Crossover?????

pkquat · February 2016

Polkaguy58 wrote: »

Well now, this post might just get me booted out or sent to the hall of shame for heresy, but here goes...................
As I mentioned in the above post, I tried switching a pair of Monitor 5 crossovers into a pair of my 5 Jr's and liked the outcome, which was a lot less midrange honk.
What I didn't do until just now, was to listen to the Monitor 5's with the Jr's crossovers.
It had the exact opposite effect and added mids to the 5's, which I thought were a little on the darker side in their stock form.
The obvious next move was to try them all together.............and it only got better !
I'm a happy camper now and haven't even gotten to sealing up the cabinets and swapping new caps in yet !
Let the stoning begin.

These are Monitor 5B's or Series 2 and 5jr's that originally had or have the SL2000 or SL2500 tweeter correct? If the cap values are different depending on the tweeter that would change things.

I think the tweeters cross over at around 3K. I had poked around trying to figure out the difference between the two caps for the SL2000 and SL2500 tweeters. I couldn't get the values to line up perfectly without changing the resistance on the basic online calcualtors, but when I did change the resistance, crossover points lined up very close to the same value. Within 200Hz or less if I recall.

I too wondered why they were different, other than possibly lowering the cost of the 5jr's. I think the MW on the 5jr's have a 6db slope crossover, while the 5B's have a 12db slope crossover. My speaker design book is buried away somewhere and I don't remember the specifics. I want to say the crossovers are separate, but I could be wrong, there might be some interaction.

The difference in crossovers is what made me wonder if there were 8ohm and 4ohm versions of the MW6502.

xschop · February 2016

MW6501 was 8 ohm

Polkaguy58 · February 2016

They say if you lock a monkey in a room with a typewriter long enough, eventually he'll type Shakespear...................and so it goes with old men and their speakers.
I think I really hit on something with this Monitor 5/5Jr crossover swap.
The cool thing is that if you happen to own a pair of each, nothing is hurt by trying the swap.
Both crossovers have the same mounts and the speakers all connect with simple spade terminals.
I just finished listening to Fleetwood Mac's Rumours CD and heard things I don't think I've ever quite noticed before.
One thing that stood out was how I could actually hear Mick Fleetwoods drum heads like I was right next to them !
I'm not running any special gear, just a Yamaha Natural Sound 100 watt x 2 receiver.
My speakers leak air and that will be my next mod.
I've already impregnated all screw holes with superglue, by putting a drop in each hole, then working the glue inside with a toothpick.
This trick toughens up the side walls and keeps the threads from stripping.
For gaskets, I'm going to stick to my tried and true method of using clay rope caulking.
It not only makes a great seal, but isolates the frame from the wood to help keep vibrations from the cabs and is easily removed with your fingers.
The trick is to tighten your screws like you do your cars lug nuts.......a little pressure on each in a cross pattern, so not to bend the frame of the speakers.
I'll be ordering up some caps also.
If things sound this good now, that can only make it better.

xschop · February 2016

I like the simplicity of these 5JR crossovers.
I would like to use this spare set in my MTM or TMM that I'll be building shortly.

Maybe more of a question for Polkaguy58 or WMG... Since they are designed for an 8 ohm tweeter and 4 ohm woofer, would it be OK to use 2ea 8ohm MW's in parallel with same 5JR crossover?

codycatalist · February 2016

@Polkaguy58 I'm missing gaskets on my 5s you prefer clay rope chaulking to make a good seal?

Polkaguy58 · February 2016

I would imagine a 4 ohm load is a 4 ohm load, but I'm far from an expert.
I use Mortite clay caulking rope and always have.
The only trick to it, is don't torque down one screw at a time.
Tighten them in a criss cross patern a little at a time, so you don't warp the speaker frame.

ken brydson · February 2016

Most prefer Armacel over mortite these days.

Polkaguy58 · March 2016

xschop wrote: »

I like the simplicity of these 5JR crossovers.
I would like to use this spare set in my MTM or TMM that I'll be building shortly.

Maybe more of a question for Polkaguy58 or WMG... Since they are designed for an 8 ohm tweeter and 4 ohm woofer, would it be OK to use 2ea 8ohm MW's in parallel with same 5JR crossover?

I don't know Polk crossovers well enough yet, but am curious as to what Ohmage the Monitor 10 woofers are.
I was surprised to see only four leads coming off of the crossovers, just jumper leads from one woofer to the next.
I would guess that the 10's are running two four Ohms to make 8.
The model numbers are different from my 5 Jr's, so I'm hesitant to try my two active woofer trick on my spare Jr.s

codycatalist · March 2016

I was surprised to see only four leads coming off of the crossovers, just jumper leads from one woofer to the next.

That's how my rta11tls are too.

Polkaguy58 · March 2016

Well, I tore down all six Monitor 5/5Jr's, put the locktite powergrab on the magnets, used Mortite for my gaskets.
I reverted the nicer set of Jr's back to the stock crossovers, but kept the 5 Jr crossovers in my Monitor 5's, as they really do sound better to me that way.
I'll rebuild the Monitor 5 crossovers and see which sounds best when their done.
I now have a pair of Jr's (the shabbier pair) to putter around with.
One thought is to just plug up the tweeter hole (I still have some fiberglass tray material) and find a nice coaxial speaker to go with the passive, for a Point reference style speaker.
I'd do this by turning them upside down, putting the passives in the center and the new coaxial driver up top (or former bottom)
Most good quality coaxial's have their own crossover built in, so I'd just make a blank cover for the back and install some binding posts.
My other option is to run the woofer's unfettered (no crossover) and just put an inline mylar cap and L-Pad on the tweeter.
This is how my favorite T-100's were wired and they sounded awesome !
My only problem, is that I haven't been able to find out what the Polk 6.5 woofer's drop off frequency is, so I can pick the right cap to blend into the slope.
If I had to guess, I'd say around 6000 Hz or so.
Anyone here know by chance ?

Monitor 5s...different cross overs?

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