Refurb'ed and upgraded M5's...now they're going to a new home.

geoff727

Hello all,

I just completed this project for a good friend of mine. He wanted a speaker that was "black", that was an upgrade to his old and small KLH's, but that was done to a fairly tight budget. Everyone knows what a stock Monitor 5B looks like, so I won't post any pictures of them in their original state. I have had these since high school, they were my very first pair of Polk's. Here's the TLC that these got.

1. Crossover upgrade. I replaced all the old electrolytics. I wanted to give my friend something just a bit better than the SOLEN's, but he couldn't quite make the jump to SONICAP's, so I finally decided on the ClarityCap PX's. Resistors were replaced with Mills. Tweeter protection switches were removed. Stock wire was replaced with Monster Cable. And, new Vampire binding posts.

2. Piano gloss black finish. It's really hard to get a good picture of this; I tried to get a couple of the reflections. I partially finished the lip on the back of the speaker. Mostly, I just wanted to make it the same color as the front and sides, and to seal the particle board so it didn't look so cheesy.

3. Installed the mid/bass, crossover cup, and PR using T-nuts and allen-head screws. Installed the tweeters with large-thread brass inserts and allen-head screws. Used more substantial foam rings around the mid/bass and PR. Used Dynamat on the frames of the mid/bass and PR's.

4. Added some cross-bracing dowels inside the enclosures, and some foam to reduce internal reflections.

5. New binding posts.

6. Refurbished the original stands that I had for them with a good sand, rosewood stain, and hand-rubbed lacquer (and felt feet for my friend's hardwood floor).

7. The tweeters are currently wired out-of-phase. No long talk here about second-order crossovers and low-pass/high-pass phase relationships, differences in summing, and driver locations on the baffle (blah, blah, blah). In essence, I'm going to do some listening with the tweeters out-of-phase and in-phase, and see which is better overall for the intended space and application. Might experiment with different amounts of polyfill also.

We agreed to listen for a while and see how things sound to his ears before committing to any other price points, like the RD tweeters. They've been playing all day, and by tonight they were really starting to 'wake up'. Pretty simple upgrade, overall (but the finish is a bit time-comsuming!). After this though, unles another friend wants my Monitor 10's or SDA 2B's with some work done on them, I simply MUST start working on some of my Infinity's. Gee, I still have to finish those Mission 70's too. Almost forgot! :rolleyes:

Hope you all enjoy, I'm off to RMAF in Denver in the morning.

Geoff

Face

Nice job!

Jeff Beaird

geoff727 wrote: »

After this though, unles another friend wants my Monitor 10's or SDA 2B's with some work done on them

Geoff

Can I be your FRIEND..! PPppllleeeaaassseeeeeee!:p

zingo

Those look awesome! I bet they sound killer too.

leroyjr1

Looks nice.

ShinAce

Beautiful finish, mission accomplished.

IrishNiner

Geoff,

Great job on the speakers! I too would like to know how you did the piano gloss finish. I have a set of RTA 15tl's I may like to try that on.

Farrell

cambir

Geoff - those turned out incredible! Nice work!

Can't wait to see how those 2B turn out. :cool:

geoff727

Thanks for the compliments everybody. Cameron, I still hope you can swing by one of these days. Jake, you are always on an open invite as well. I know we talked about getting together once upon a time but never did.

For the finish, this is basically what I did.

1. Stripped the old veneer with a heat gun.

2. Sanded and filled the particle board. This takes LOTS of filling and sanding.

3. Sealed and smoothed the particle board with Deft sanding sealer, about 10 coats, dry- sanding between each one with about 600 grit paper.

4. Painted the enclosures with KRYLON flat black out of a plain rattle can.

5. Lightly wet-sanded the black paint after it dried with about 2000 grit, and thoroughly cleaned it.

6. Applied around 20 coats of Deft gloss lacquer, wet-sanding between each one with about 2000 grit. Although tedious, I found this absolutely necessary to achieve a mirror-flat finish; the particle board is so fluid and develops litle depressions and pores seemingly out of the blue. Each one of them has to be filled in by repetitive spraying and sanding. So, it's a good idea to let several coats of lacquer cure over the course of several weeks to let it completely harden into any pores before applying more coats. That's why these speakers took me several months to do. The crossovers- 1 day, the finish- about 4 months. It would have been much easier applying this finish over something hard, like metal.

To anyone who wants to try it, this particle board ain't easy to do this on. I'm even wondering if these will require a "re-finish overcoat" in a couple years after enduring vibration from playing music and jiggling the particle board. I'm curious to see if the lacquer will sink in spots. Hopefully not.

Heard the Holy Grail of home audio at RMAF this year- the Marten Coltrane Supreme's driven by LAMM ML-3 monoblocks. What an experience. It was very moving, that's all I can say. I spent lots of time in that room.

zingo

That is a lot of you put into those Geoff and they look amazing! And thanks for the invite again. I've been such a work bum lately that my social life has been very limited. I been looking at putting on a Polkfest in the area, so maybe that would get all us Northwest folks together.

John30_30

geoff727 wrote: »

Thanks for the compliments everybody. Cameron, I still hope you can swing by one of these days. Jake, you are always on an open invite as well. I know we talked about getting together once upon a time but never did.

6. Applied around 20 coats of Deft gloss lacquer, wet-sanding between each one with about 2000 grit. Although tedious, I found this absolutely necessary to achieve a mirror-flat finish; the particle board is so fluid and develops litle depressions and pores seemingly out of the blue. Each one of them has to be filled in by repetitive spraying and sanding. So, it's a good idea to let several coats of lacquer cure over the course of several weeks to let it completely harden into any pores before applying more coats. That's why these speakers took me several months to do. The crossovers- 1 day, the finish- about 4 months. It would have been much easier applying this finish over something hard, like metal.

To anyone who wants to try it, this particle board ain't easy to do this on. I'm even wondering if these will require a "re-finish overcoat" in a couple years after enduring vibration from playing music and jiggling the particle board. I'm curious to see if the lacquer will sink in spots. Hopefully not.

Those pores and depressions are most likely 'orange-peeling'. It can be from high humidity when you spray, imperfections in the material, etc.
Sorry you had to go thru such grief, but it looks like a really sweet job.

danger boy

nice and very unique pair of vintage Polks redone.. great looking pair and you did a killer job on them.

geoff727

John30_30 wrote: »

It can be from.... imperfections in the material, etc.
Sorry you had to go thru such grief, but it looks like a really sweet job.

Yes, the material is definitely imperfect. However, I knew that when I started- I knew that this wood would be especially porous. This finish on these speakers was a "proof that I can do it" on this enclosure material as well. It wasn't really any grief, just time-consuming. However, I'm pleased to say the finish looks better than many of the gloss finishes I saw on speakers at RMAF over the past few days. And, not quite as good as some others. The finish on the Coltrane's was a bit nicer! :rolleyes:

Thanks again for the compliments.

Geoff

halo71

Sorry to resurect an old thread. And this may be a dumb question. But if one was to leave the original vinyl finish on the cabinet and do the piano finish as described above. What would be the outcome, bubbling in the finish perhaps? If not, seems like leaving the original finish on would give a better smoother finish. And not have the issues with the porous partical board.

BTW.....AWESOME refinish job Geoff!

Litz

Can you describe a little the changes I can expect from the upgrades? IE: is there simply a clarity or resolution improvement or more?

geoff727

halo71 wrote: »

Sorry to resurect an old thread. And this may be a dumb question. But if one was to leave the original vinyl finish on the cabinet and do the piano finish as described above. What would be the outcome, bubbling in the finish perhaps? If not, seems like leaving the original finish on would give a better smoother finish. And not have the issues with the porous partical board.

BTW.....AWESOME refinish job Geoff!

I'm no expert at any of this, but....I don't think there's a way to fill in the faux wood grain imprinted in the vinyl. At least not reliably. And that would make things REALLY difficult!! In fact, it might just be easier all around to build up the sides/tops/bottoms of the speakers with 1/4" MDF (a more stable substrate, making the speaker a bit larger in the process, and do the finish over that (removing the vinyl). In fact, I've been thinking about that for my pair of 15tl's. It would have to be done properly, but would have the added advantage of making the enclosure a bit less resonant (presumably).
G~

geoff727

Litz wrote: »

...is there simply a clarity or resolution improvement or more?

Yes and yes, without a doubt. The speakers (to me) become much more listenable and musically involving over longer periods.

sbolt

Hi Geoff, I have been looking at your restoration posts and I have a couple of questions since I want to do restore my used boxes I just got.

1) Dynomat on the baskets - what does this do? I am assuming it may prevent reflections from the metal? Do you Dynomat the interior of the box as well?

2) Could you please briefly describe the cross bracing and the type of wood you used?

Thanks for your help and great work!

geoff727

sbolt wrote: »

1) Dynomat on the baskets - what does this do? I am assuming it may prevent reflections from the metal? Do you Dynomat the interior of the box as well?

Dynamat (actually, Dynamat Extreme is the stuff you want to get) simply helps dampen vibrations of the basket. If you flick the edge of the basket with your finger, it will ring perceptibly for a couple of seconds, just like a bell. Once the Dynamat goes on, this ringing is transformed into a quickly-decaying THUD.

Sound waves impinging on the driver baskets also cause some microscopic movement, and therefore ringing, of the driver baskets. If you were to observe this on a microscopic level, you would see this motion of the basket; that motion gets transferred into the entire magnet structure of the driver. This, in turn, causes relative motion between the magnet and the voice coil that's not supposed to be there....distortion. Dynamat helps to cut out the prolonged ringing of the basket. It may or may not be perceptible, depending on you and your system, but as they say, "It can't hoit!" You can Dynamat almost any surface you feel like...driver baskets, inside of the enclosure, capacitors, a crossover board, HVAC systems, noisy air vents, your computer case, dishwasher, refrigerator, car interior, etc.

sbolt wrote: »

2) Could you please briefly describe the cross bracing and the type of wood you used?

Thanks for your help and great work!

Im' trying to remember back a while here, but I believe I just used some pine or oak dowels to 'firm up' some of the larger unbraced panel sections. This may be dubious with something the small size of a 3/4 inch dowel. Basically, the point is to reduce the unsupported panel areas, so they become smaller in size. This will result in them naturally resonating at higer frequencies, which are easier to damp and control than lower frequency resonations. But, you have to be cautious about changing the internal volume of speakers. Reducing the internal volume changes the performance parameters of the bass response.

Post pics and the process of your upgrade.

G~