Starting on 5jr rebuild...

dpgaloot

Hey guys,

I'm going to take the dive and do a rebuild. I have had a pair of 5jrs kicking around for a month or two that I essentially got for free with another purchase. I've read several threads here on this, and have put together the following list:

1) Remove vinyl and replace with real wood veneer.
2) Crossover rebuild - get help.
3) Upgrade the speaker posts.
4) Dynamat the drivers (use Dynamat Extreme).
5) Sonic Barrier the interior of the cabinet.
6) Install RDO194s.
7) Install new seals?
8) JB Weld the drivers.
9) Upgrade the wood screws to T-nuts or rings or something.

I'd certainly like to hear if I'm missing anything. Think I'm going to ask around to have someone else do the crossovers, feel free to PM me with any recommendations here. I'm a fairly decent amateur woodworker, so that part I can handle. The electronics are new to me.

Tonight I disassembled the speakers and removed the vinyl. I cleaned the inside of the cabinets, there wasn't much to do. I've seen some posts here with glue hell, mine weren't too bad. I'll order some parts in the next few days, and hopefully get a few evenings next week to start working on the veneer (I usually make my own, 3/16" thick resawn from lumber).

A few pics of the process so far. Wish me luck!

Oldfatdogs

What type wood are you going to use?Good luck with your project.

TNHNDYMAN

dp-
I'm wanting to do some veneering on a older pair of Monitor 10's and would love to see alot of pics of the process and any step by step tips you could provide. (Especially the front beveled edge) I've never done any veneer work and want to learn some pointers from those more expierence before attempting.

dpgaloot

Hey guys,

I'm trying to decide what kind of wood to use. Right now it's down to black walnut or mahogany. I'm going to be re-doing a vintage receiver at the same time and in the same wood, so there is more to consider than just the speakers.

HNDYMAN, funny you should say that. I have a pair of beat Monitor 10s that have been in my shop for years now. I'm thinking that if the 5 jrs turn out well, those are next on the list. I'll re-do them and swap them with the 10s upstairs. I have done traditional veneer in my shop, I do have a vacuum press which makes it a LOT easier. On this project, I'm thinking I'll resaw my own veneer to make it substantially thicker than commercial veneer. I think that it will hold up better than veneer does. I'm also thinking about the bevel on the front, that will be fun. If you haven't seen Boywonder's thread you should check it out:

http://www.polkaudio.com/forums/showthread.php?61901-Veneering-my-Monitor-10-s

I like his solution a lot!

I ordered the dynamat, sonic barrier, mortite, grill fabric and new guides last night. I'm committed now!

Toolfan66

Just put a couple of strips of sonic barrier on the inside of the cabinet "don't fully cover it"

Good luck!!

soundfreak1

Love to hear how they turn out. Just got my order from madisound to do the 5jr+ speakers I found. Clairity caps (Sa) mox1 resistors and gold binding posts,gold terminators,new wire and dynamat. Can't wait to get started. Good luck.

inspiredsports

Nice project!

I mentioned this in another post that escapes me, but wanted to let you know here too.

Most 5jr's had an SL2000 tweeter that used a 12uf capacitor in the crossover. If you were considering both updating the crossover AND replacing SL2000 with the drop in replacement RDO194-1, you might consider replacing the 12uf cap with a 13.8uf cap and upgrading to the RDO198-1 that sounds (in my humble opinion) even better.

It's a better bang-for-the-buck as you are alreading investing the labor, the RDO194-1 and RDO198-1 cost exactly the same, and the 13.8uf cap only costs a few dollars more.

vstarkwell

COOL!!!!, I'm looking forward to seeing this project through to completion. Best of luck!!!

dpgaloot

Hi Inspired and Toolfan,

Thanks for the tips, I appreciate them. I haven't ordered the tweeters yet so the 198s are still a possibility. Soundfreak, I hope you post your progress.

Joe08867

Like Toolfan said, just a couple of strips of sonic barrier and do not place it on the wall behind the passive radiator. Keep it up above that area. It makes them sound all wonky otherwise.

Good luck,

Big Dawg

inspiredsports wrote: »

Nice project!

I mentioned this in another post that escapes me, but wanted to let you know here too.

Most 5jr's had an SL2000 tweeter that used a 12uf capacitor in the crossover. If you were considering both updating the crossover AND replacing SL2000 with the drop in replacement RDO194-1, you might consider replacing the 12uf cap with a 13.8uf cap and upgrading to the RDO198-1 that sounds (in my humble opinion) even better.

It's a better bang-for-the-buck as you are alreading investing the labor, the RDO194-1 and RDO198-1 cost exactly the same, and the 13.8uf cap only costs a few dollars more.

I've got a pair and am doing exactly that!

soundfreak1

I hope I didn't get the wrong caps? I got the clairity (sa) 12uf and a 1.5 uf to make a 13.5 uf total for the 198 tweets I haven't seen anything that would get me too 13.8 uf I though it was 13.5 for the rdo198's. Please let me know if this is wrong before I install them. Thanks.

dpgaloot

Thanks for all the good ideas. I'm going to do some work on the cabinets to day, I'll get some pics on later. I do have a couple of questions though...

I ordered new fabric from parts express for the grills. I got the vintage black stuff, it looked great online but I hate it. It is all plastic feeling like cheap astroturf. Any recommendation on fabric to redo the grills?

Also, I like the concept of rings to reinforce the cabinets where the drivers are secured. I can't fabricate metal ones, but what about making some out of 1/4" or 1/2" birch plywood? This would reinforce the front baffle, and should give the drivers a much more secure footing. Asking for trouble here?

thanks...

dpgaloot

Well, had a few good hours in the shop. Got the Dynamat and JBWeld installed on the drivers. I've had magnets slip loose and ruin drivers, so I was glad to learn the JBWeld trick. I sealed the cabinets and painted the interiors. Got a little overspray on the front bevel, that's okay because it's coming off and going to be replaced with real wood.

I'm excited to get these done and listen to them. I have a pair of stock 5's, I'm looking forward to hooking those and the modded 5 jr's up to the same amp and doing A/B testing. Other than the grill cloth I've got everything ordered and on the way to finish this project.

Thanks to all who have shared their experience here.

vcwatkins

Good work. Nice shop too. I've never delaminated anything. How long did that take you and did you use only heat?

vcwatkins

Lasareath wrote: »

Good Luck with your project!

You don't want to get some exotic wood?

This is the place I bought the wood for my 1.2tl's

http://www.cookwoods.com/lumber-site/shop/category/veneer/

But the wood I used was one piece 15" by 165" by 1" thick

Sal

Pretty stuff there. Love the burl. Getting ready to do some 5b's and think I might try your source. Thx.

dpgaloot

Thanks for the comments all. I'm having fun on the project.

Sal, I've looked at exotic woods and worked with them as well. These 5 jr's are going to one of my kids, and I expect they will be traveling around a lot over the next 10 years. I'd feel better with homemade veneer which I might make as thick as 1/4", it will take the bumps and jolts much better than thin exotic veneer. I have enough macassar ebony veneer from another project to do a set of speakers though, maybe for myself.

VC I just used a heat gun and my fingernails to strip the vinyl. Took about 45 minutes, but they are 5 jr's after all. The vinyl came off in almost a whole sheet per side, I just took my time and let the heat do its thing. The shop is still kind of a wreck, one of those things where I need to get a few projects done and out of there before I can put it right.

I'm refinishing the cabinets on a set of JBL L220s right now, it is interesting to compare the cabinets of the Polks and JBLs from similar vintage. Very similar construction, but the JBLs did include T-Nuts and real wood veneer. I'm surprised such a big cabinet is still made out of 3/4" particle board. I'm going to use some of what I've learned here when I put the JBLs back together, at least to seal the drivers to the cabinet.

Next week I'm planning to install the sonic barrier and start veneering the cabinets.

soundfreak1

Very nice work.

geoff727

dpgaloot wrote: »

I have enough macassar ebony veneer from another project to do a set of speakers though....

Perfect!!

Beautiful stuff!

geoff727

dpgaloot wrote: »

....I got the vintage black stuff, it looked great online but I hate it. It is all plastic feeling like cheap astroturf. Any recommendation on fabric to redo the grills?

Personally, I like the black speaker grill cloth from JoAnn fabric stores. That's the stuff I always use; it's a tighter weave than the original grill cloth and I think it looks quite professional and clean. Should be several in your area.

G~

downhiller2010

Real clean work!, hope mine look this good when I'm done with them

dpgaloot

Hey all,

I got a few hours in the shop today and made some progress on my rebuild. I was able to resaw some walnut and plane it down to just under 1/4" for veneer. I left the pieces long enough that I should be able to wrap the grain up one side, across the top, and down the other side. That should withstand the bumps pretty well and may even reinforce the cabinets a hair.

I also ran the cabinets through the tablesaw to make the back flush (I'm going to veneer the backs) and take off the bevel on the front. I'm going to make a solid walnut bevel rather than trying to veneer the bevel. It came off easier than I suspected it would. I was worried about loosening the front of the cabinet, but Polk didn't have any glue there anyway. I'm basically copying what Boywonder did on his veneering thread here:

http://www.polkaudio.com/forums/showthread.php?61901-Veneering-my-Monitor-10-s

I have already received the new tweeters, and the crossovers have been rebuilt and are on their way back to me (thanks Geoff727). Next week I'll work on installing the sonic barrier and veneering the cabinets.

Thanks again to everyone here for your encouragement and input. I'd have never have had the courage to tear apart my polks without the benefit of your experience.

vstarkwell

This is great!!!, looking forward to more updates.