Rebuilding Monitor 10a's into Monitor 7 based towers... Thoughts?

jonwb

Hi,

New here. I've stored some 1985 Monitor 10a's (Peerless) for about seven years now in our garage. For some reason our new house just didn't accommodate the speakers with its "smallish" LR and fireplace design. Plus, my wife thought they looked too boxy.. too 80s (whatever that means?)

In an effort to bring music back to our environment, I recently re-veneered an old Pioneer SX750. Now, because of their diminished value, I'm thinking about downsizing the 10s into a Monitor 7 design spec with a built-in raised stand. Smaller, taller, walnut veneered and more modern looking. I have the components and the means. I've always loved the Polk sound.. plus the imaging should be better using the 7's single 6.5" mid/woofer design.

Does this make sense or does this sound like a bad idea?

Mystery

Sell the 10's as it is and buy new slimmer/taller Polk monitor 70's.
That's my advice.

gmjungbluth

It sounds like an interesting project.

From what you write, am I correct that you would like to take the components from a Monitor 10 (2 6.5" drivers, Peerless Tweeter, 10" passive radiator) and fit them into a smaller, more narrow cabinet?

Technically that could work if you use all the components - both 6.5" as well as the tweeter and the radiator. But if you go to a cabinet with a smaller internal volume it will affect the bass response and frequency range you will be able to get.

Also, if you want to only use one of the 6.5" drivers in each cabinet instead of the original two (like the Polk 7 design), you will have to modify the original Monitor 10 crossover - it won't work just to use the same crossover and not hook up one speaker. You'll have to move towards a Monitor 7 or Monitor 5 crossover - the specs and schematics are stickied on this forum.

I think it would easier for you to sell the Monitor 10s and find a pair of Monitor 7s or Monitor 5s, which are already smaller in size and whose crossovers are already set up for a 2-way speaker. If you found some Monitor 5 or 5JRs, it would also be easier to mount those components into a newer and narrower tower cabinet due to the smaller passive radiator. Where I am located in the metro DC area Polk monitor speakers come up pretty regularly on Craigslist and it wouldn't be hard to find a set of 5s or 7s, sell your 10s if you are so inclined and come out a little ahead.

Otherwise if you are able to modify or build crossovers from scratch and are interesting in purposing your existing components there is no reason why your approach would not work.

I hope this is helpful. Good luck and enjoy!

jonwb wrote: »

Hi,

New here. I've stored some 1985 Monitor 10a's (Peerless) for about seven years now in our garage. For some reason our new house just didn't accommodate the speakers with its "smallish" LR and fireplace design. Plus, my wife thought they looked too boxy.. too 80s (whatever that means?)

In an effort to bring music back to our environment, I recently re-veneered an old Pioneer SX750. Now, because of their diminished value, I'm thinking about downsizing the 10s into a Monitor 7 design spec with a built-in raised stand. Smaller, taller, walnut veneered and more modern looking. I have the components and the means. I've always loved the Polk sound.. plus the imaging should be better using the 7's single 6.5" mid/woofer design.

Does this make sense or does this sound like a bad idea?

anton.chigurh

jonwb wrote: »

does this sound like a bad idea?

Yes!!! Cannibalizing your 10As into Frankenpolks sounds like a bad idea. Definitely sell them if they wont work for your application.
Not sure your project will retain that Polk sound you like after cabinet changes and with crossover differences. Depending on room size and boxiness/80s tolerances, I would look for a minty pair of smaller Monitor 7, 5, 5jrs as suggested. Good luck.
















Depending on the size of the room, and boxiness/80s tolerances I would consider the smaller Monitor 7,5, or 5jrs.

boston1450

WELCOME TO POLK. The 7's would sound sweet on that SX750 IMO---- out of all my speakers i have they WILL BE the first to be upgraded. They are the perfect size IMO

jonwb

Well, I appreciate your responses. Yes it would be easier to sell them. Problem is... I don't think I could. I was the original owner and I've had them since I was 25 (I'm 53 now). The cabinets are not in good shape.. and frankly I've never been a big fan of the rosewood vinyl. Even if I re-veneered them they still would look big and bulky. For me, this is a way to keep the components.. the sound.

As far as the cabinet, picture an exact Monitor 7 MDF design (23hx13wx10"d) as the main enclosure raised by about 18" (no separation though along the sides). Concerning the crossover, I did in fact think I could eliminate one 6.5 driver by not hooking it up. I had thought the same crossover frequencies were fed to each 6.5 driver.. thus creating the imaging problems the Monitor 10s are accused of? Will look into that.

Believe me, finding some beat up Monitor 7s here in CA would be easier. I've even looked for raw Monitor 7 cabinets so I could transfer components! (think that's easy?... no). If anyone has some suggestions to finding some other than ebay or craigslist, I'm listening.

Thanks

jonwb

boston1450 wrote: »

WELCOME TO POLK. The 7's would sound sweet on that SX750 IMO---- out of all my speakers i have they WILL BE the first to be upgraded. They are the perfect size IMO

Thanks.. and I agree!

westmassguy

jonwb wrote: »

Well, I appreciate your responses. Yes it would be easier to sell them. Problem is... I don't think I could. I was the original owner and I've had them since I was 25 (I'm 53 now). The cabinets are not in good shape.. and frankly I've never been a big fan of the rosewood vinyl. Even if I re-veneered them they still would look big and bulky. For me, this is a way to keep the components.. the sound.

As far as the cabinet, picture an exact Monitor 7 MDF design (23hx13wx10"d) as the main enclosure raised by about 18" (no separation though along the sides). Concerning the crossover, I did in fact think I could eliminate one 6.5 driver by not hooking it up. I had thought the same crossover frequencies were fed to each 6.5 driver.. thus creating the imaging problems the Monitor 10s are accused of? Will look into that.

Believe me, finding some beat up Monitor 7s here in CA would be easier. I've even looked for raw Monitor 7 cabinets so I could transfer components! (think that's easy?... no). If anyone has some suggestions to finding some other than ebay or craigslist, I'm listening.

Thanks

Your theory will not work for several reasons. The Monitor 10s crossover was designed and balanced for two 8ohm woofers in parallel which is 4 ohms. If a single 8 ohm woofer is connected, the lo-pass crossover frequency doubles. For example, if the crossover frequency is 2000 Hz @ 4ohms, it now become 4000 Hz @ 8ohms, and the slope of the cut-off will be very different. Your woofer and tweeter will now overlap a full octave, not good.
The original Monitor 10s 8ohm woofers T/S parameters are very different than the 4ohm woofers used in the Monitor 7s. The VAS, or the amount of air moved by the woofer's cone, is double with the 8ohm driver vs the 4ohm driver.
Lastly, the 10" Passive Radiator is weighted differently between the 7 and the 10. PRs are tuned to a certain frequency and cabinet volume, much like a port.

jonwb

Well there you have it... solid information that discourages the time and effort. Thanks.. you saved the 10's!

Ironically last night I came across some local Polk Monitor 11t's for sale. There similar to my envisioned design and actually not as wide... which is a plus. People here seem to like them. I might make an offer later today. Also found some Monitor 5jrs with the 6.5 passive radiator for less than $75. Both would need new veneer, and the 5's would need stands and most likely a sub.

westmassguy

jonwb wrote: »

Well there you have it... solid information that discourages the time and effort. Thanks.. you saved the 10's!

Ironically last night I came across some local Polk Monitor 11t's for sale. There similar to my envisioned design and actually not as wide... which is a plus. People here seem to like them. I might make an offer later today. Also found some Monitor 5jrs with the 6.5 passive radiator for less than $75. Both would need new veneer, and the 5's would need stands and most likely a sub.

The 11Ts would be an excellent choice, and no sub needed for normal 2 channel listening.

anton.chigurh

westmassguy wrote: »

The 11Ts would be an excellent choice

^^Agreed^^. Check em out. Consider upgrading the tweets or doing the full "TL" mod down the road if they're in good condition.

jonwb

Sounds good. I don't know the age or current values of these. They have some cosmetic issues and would need to be veneered, but the drivers look to be ok. They're branded:

Polk Audio
Monitor Series
11t (followed by the serial #)

Would $160 be a fair price given the needed upgrades (cosmetic and future electronic)

Mystery

jonwb wrote: »

Sounds good. I don't know the age or current values of these. They have some cosmetic issues and would need to be veneered, but the drivers look to be ok. They're branded:

Polk Audio
Monitor Series
11t (followed by the serial #)

Would $160 be a fair price given the needed upgrades (cosmetic and future electronic)

Not sure.
That's a good price if they were in excellent condition.

My suggestion is still Polk Monitor 70.
Polkaudio directly sells via ebay for $375 refurbished and free shipping.
http://www.ebay.com/itm/Monitor-70-BLACK-Tower-Speakers-Polk-Audio-PAIR-/390573844276?pt=Speakers_Subwoofers&hash=item5af003e734

Rakuten has them for $339 but doesn't mention if it's for the pair.
http://www.rakuten.com/prod/polk-audio-70-275-w-rmsspeaker-5-way-black-30-hz-to-25-khz-8-ohm-floor/204087657.html

They are liked by a lot of folks here and no need to fix anything.
I'm not sure how the compare with vintage monitors though.
Others can chime in.
But if you really want vintage and slim, then the only options are RTA-8t, 11t or LS line.

boston1450

Attachment not found.This little 16wpc Sansui hooked to the Monitor 5jr+'s would surprise you''to say the least. Small receiver perfect match up to ME and i dont need any sub--those are Monitor 10stands..dont let 5jr+ monitor size fool ya..pick them up for 50-125.00 which is a great deal

westmassguy

DSkip wrote: »

Have you considered rebuilding them as M10's in a new, slimmer tower, with the passive radiator on the side like the LSi15/25? I'm not sure if MTM or TMM would work best, but if you're set on a project and want to keep the bulk of the speaker for sentimental reasons, this might be worth looking into

That's an Idea. Find a knockdown, narrow enclosure, with the same internal volume. It would actually look similar to the 8T or 11T

jonwb

Thanks for the links. These would be for 2 channel audio only. No plans for a theater setup. I assume the 70's bass response would be similar to the 11t but the 4x6.5 driver setup scares me a bit? Fullness in sound is what I'm used to with my vintage 10s. Could anyone compare the two?

jonwb

Oh wow... a lot of replies now... thanks. Have probably given up on rebuilding anything at this point. Too many variables involved... but some good ideas. The 5jrs are still a contender.. thanks! Re-veneering the 11ts would be fun. The newer PSA veneers are easy to cut, apply and stain. If everyone agrees the "cosmetically challenged" 11ts are too high at $160, I could offer lower. (seller wants $200)

StantonZ

I have had my 10B's about as long as you've had your 10A's (bought my first pair in 1985), and would much rather see you sell them than "tear them down". They really are great speakers (especially if you have peerless tweeters).

boston1450

Even a banged up pair working 10's is a wanted speaker. Looks dont effect sound. And repairs can be made from a crafty person. All the choices you mentioned above are great ones. Your call. Your budget.

jonwb

Have decided NOT to "tear them down". There in perfect working order. I'll re-veneer them one day and give them to one of my sons (the one with the most cash!)

I "know" and like the vintage Polk sound. That's why the 11ts (at only 10.5" wide) have my interest. These are the original ones, built from '90 to '92. I now have a vintage receiver (the SX750) and I'd like to keep the look of all the components from the early era. Here they are.. you can see the tops are scratched up pretty well.

westmassguy

What's the white crusty stuff on the top and front? Were they in a barn or something? Better make sure it cleans off, otherwise you'll be laminating the front baffle too.

jonwb

westmassguy wrote: »

What's the white crusty stuff on the top and front? Were they in a barn or something? Better make sure it cleans off, otherwise you'll be laminating the front baffle too.

LOL.. you might be onto something? I could sand and respray that. HOWEVER... check the other pic. Is that water damage on the back? Don't tell me it's mold!

jonwb

DSkip wrote: »

I don't see $160 as unreasonable for those, again thinking in terms of driver cost. Figure each driver in working condition sells for $30-35 easy, you're playing it safe around $150.

I agree, the drivers look ok. Cabinet though?

westmassguy

jonwb wrote: »

LOL.. you might be onto something? I could sand and respray that. HOWEVER... check the other pic. Is that water damage on the back? Don't tell me it's mold!

Water damage for sure. The particle board is expanded. I've Refinished worse than that, but that's up to you.

westmassguy

In either case, water or moisture damage, close inspection is required, and your nose will tell you right away. Can't hide that nasty, musty smell.

jonwb

Yeah as long as I'm not dealing with mold, I could handle that. My 10s have some raised vinyl on the back from the year we left the Halloween pumpkin on top of it too long. Didn't know those things eventually leak. I was not amused...

I think they're worth $160 based on the outrageous prices I see on eBay. There about an hours drive from here. Should I go for it?

westmassguy

That's your call. They are what you're looking for, the narrow fronts.
It amazes me that people post photos like that. They don't have Fantastic and a few rags to clean them up before selling them?

Mystery

Sound wise, I'm not sure if they'll beat 10's.
I had RTA-8TL and didn't like that much but 11T may be better.
Someone here may have had both and compared.

westmassguy

Mystery wrote: »

Sound wise, I'm not sure if they'll beat 10's.
I had RTA-8TL and didn't like that much but 11T may be better.
Someone here may have had both and compared.

The 8ts are ported right? They won't perform like the 11s

TennMan

I have to agree with westmass. Looks like water damage on particle board to me.

LOL.. you might be onto something? I could sand and respray that. HOWEVER... check the other pic. Is that water damage on the back? Don't tell me it's mold!

I may be wrong but I think the front baffle is probably particle board with black vinyl over it. I wouldn't count on sanding and respraying that if you want it to look good. I would pass on those and look for some with better cabinets. I think you could do better at that price.

westmassguy

It's all academic, it's his call, and he has to see them with his own eyes, and nose