Polk RT7 information.

lanchilelanchile Posts: 566
edited October 2013 in Vintage Speakers
Hello, my friend is selling me a pair of Polk RT7 in MINT condition with original box and papers for $150. I would like to know if any member here have or had these speakers. How big is the 7 1/2 driver (outside diameter). all information and pictures of these speakers will be appreciated. I am not so sure ,but I think these speakers use first order crossover. I would like to put a zobel network (impedance compensator) if I buy them, but I do not know the impedance of the woofers. if it is a 8ohm driver I would use a 8ohm resistor with around 15uf cap approximate. But the problem is I do not find any specifications of the drivers to calculate the noble network.
Make it simple...Make it better!
Post edited by lanchile on

Comments

  • TroyDTroyD Posts: 12,321
    edited October 2013
    I'd go out on a limb and say that they are my favorite bookshelf speaker Polk made....don't screw them up!

    BDT
    I plan for the future. - F1Nut
  • lanchilelanchile Posts: 566
    edited October 2013
    TroyD wrote: »
    I'd go out on a limb and say that they are my favorite bookshelf speaker Polk made....don't screw them up!

    BDT

    I will not! But I was thinking putting a zobel network (impedance compensator). I am really into buying these "pristine" speakers, They look like they traveled in time! I have the RTi A1 now, But when I saw these speakers I was shocked the way they look and how much they weigh (25lb each) these speakers are very well made for sure. I know if the drivers get bad it will be difficult to get them, but I can always use the cabinets and put new drivers, crossover etc. I think I will call my friend tomorrow and buy them. for $150 I think is a good deal.
    Make it simple...Make it better!
  • TroyDTroyD Posts: 12,321
    edited October 2013
    I'm just busting your onions....I actually think the price is a little steep, IMO.

    BDT
    I plan for the future. - F1Nut
  • lanchilelanchile Posts: 566
    edited October 2013
    They used to be $450! and these speakers look like they are new! I asked him many times to go down in the price, but He is stock on the price.
    Make it simple...Make it better!
  • nguyendotnguyendot Posts: 3,587
    edited October 2013
    Yes but they are quite old. That price is very very high. You can get RT55s for that much, which in my opinion are better speakers with easier to find components. Not saying they're bad, but that's highway robbery pricing.
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  • HTguru1982HTguru1982 Posts: 1,066
    edited October 2013
    I would pass. They are incredible speakers but like Dskip mentioned, the woofers are very unreliable. I had more than one woofer fail on me in a very short amount of time. "No more", I said. The RT55's are a better option if you're wanting to stay in that price range. They may not be as smooth but they are more dynamic and woofer reliability is much better.
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  • heiney9heiney9 Posts: 24,148
    edited October 2013
    Have you heard the RT7 Lanchile? Why are you dead set on futzing with it? Like everyone else has said that price is very steep no matter what condition and the woofers are an issue.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass

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  • rooftop59rooftop59 Posts: 6,684
    edited October 2013
    I can't speak to the tweaking questions, but I will go a little against the grain here and say that I do not think that the price is highway robbery high, just on the high end. They are one of my favorite polk bookies, but as others say there are a lot of other, more recent options with more easily replaceable components. I have a pair of rt35is with modded crossovers, and I would take them over stock rt7s, and the woofers are easier to source. But I had a pair of rt7s for over a year without any problems, its just that the woofers are rare so if you DO have a problem you are basically SOL.
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  • rooftop59rooftop59 Posts: 6,684
    edited October 2013
    DSkip wrote: »
    The problem with the RT35 and other variants using that weird front baffle is that the tweeters are impossible to source. They don't have the reliability issues of the RT7 woofers, but if you do fry a tweet, you're gonna be looking pretty hard for a replacement.

    Yep that's true, but I have owned numerous speakers over the years (majority polks) and I have NEVER fried a tweeter. Some of you boys must be dead set on losing your hearing. :razz:
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  • HTguru1982HTguru1982 Posts: 1,066
    edited October 2013
    Here are a couple of replacement woofers for the RT7's. http://www.ebay.com/itm/TWO-POLK-AUDIO-RT-16-RT-7-MW8103-MW-8103-MID-RANGE-WOOFER-DRIVERS-BRAND-NEW-/161130060844?pt=Vintage_Electronics_R2&hash=item2584199c2c

    What I've been able to do my with current RT system is stock up on drivers. For the price that these RT's go for Craigslist, you can easily pick up a couple of pairs for spares. I have four tweeters and six woofers on stand by in case anything goes wrong.
    Display: Sony 42" LCD
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    Panasonic DMP-BDT110 blu ray player
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    Kenwood KM-894(surrounds)
    Fronts: NHT 2.5
    Center: NHT VS-1.2A
    Surrounds: NHT Super One
    Subwoofer: SVS PB10-ISD
  • lanchilelanchile Posts: 566
    edited October 2013
    Wow, a lot of info here. since the woofer is about 7 1/2 plus ring, I think a 8 woofer will fit ok.
    Make it simple...Make it better!
  • lanchilelanchile Posts: 566
    edited October 2013
    CRAP!!!...I guess I am screwed!!! Because I bought them already!. These things are beasts.They sound WONDERFUL.!!!! I will post pictures as soon as I get a new camera.
    Make it simple...Make it better!
  • lanchilelanchile Posts: 566
    edited October 2013
    if I knew, I would looked for the little brother the RT5...But now it is too late.
    Make it simple...Make it better!
  • HTguru1982HTguru1982 Posts: 1,066
    edited October 2013
    Spend the $90 and get those woofers on Ebay. Just in case. They are excellent speakers IMO. The sound is beyond what their cost might suggest. If they didn't have the woofer issue, I would still own them.
    Display: Sony 42" LCD
    Sources: Harman Kardon DVD-27,
    Panasonic DMP-BDT110 blu ray player
    AVR: Sony STR-DA2400ES
    Amps: Sonance Sonamp 260(fronts),
    Kenwood KM-894(surrounds)
    Fronts: NHT 2.5
    Center: NHT VS-1.2A
    Surrounds: NHT Super One
    Subwoofer: SVS PB10-ISD
  • lanchilelanchile Posts: 566
    edited October 2013
    HTguru1982 wrote: »
    Spend the $90 and get those woofers on Ebay. Just in case. They are excellent speakers IMO. The sound is beyond what their cost might suggest. If they didn't have the woofer issue, I would still own them.
    Thanks, I am thinking about it. I saw a thread that a owner did an upgrade and He upgraded the crossovers, painted the cabinets and even "change" the woofers and tweeters!. I guess He just used the cabinets and the rest was changed. I know these are very good speakers, I have them playing right now and they sound fantastic. The cabinets are super strong build and weigh a ton (25 lbs each) The crossover is first order(simple) and I was thinking putting a zobel network on those woofers (15uf capacitor, 7ohm resistor) but I have to check the impedance of woofers. I am stocked with these speakers so I have to enjoy them now and worry later when they brake.
    Make it simple...Make it better!
  • 4xoddic4xoddic Posts: 372
    edited October 2013
    I've owned 5 RT7s since new & ran them in a 5.1 HT until purchasing RTiA9s in 2009. Two now flank my basement TV & sound great. Had I been able to score taller stands that were aesthetically pleasing, I likely would have stayed with the RT7s.

    Never had a problem with a woofer (knock on MDF). Contemplating selling the 5 + a Velodyne FRS-15 for ~ $1K. Seems forum consensus = that would be on the high side.
  • lanchilelanchile Posts: 566
    edited October 2013
    Well, here are the pictures of my Polk RT7 "bookshelf speakers"...They looked like they traveled in a time machine, all the finger prints...all are mine lol.
    Make it simple...Make it better!
  • 4xoddic4xoddic Posts: 372
    edited October 2013
    Great looking pair, envious of the box! Lost the box for two of my 5 to a basement window well flood. ENJOY
  • lanchilelanchile Posts: 566
    edited October 2013
    4xoddic wrote: »
    Great looking pair, envious of the box! Lost the box for two of my 5 to a basement window well flood. ENJOY
    Thanks, I think it is a plus to have the speakers original boxes. The problem is when you do not have the space to put them. Now a friend is offering me $200 for them lol
    Make it simple...Make it better!
  • leftwinger57leftwinger57 Posts: 2,918
    edited October 2013
    They do look pristine and good luck w/ them.Not all that familiar to Polk lines but I would have taken copies of all these guys opinions of the high end cost to your "friend" and say look, over in the Polk universe they all are saying your overcharging me for these old speakers .How bout some wiggle room here.Nice looking book enders and not a scratch on them.
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  • lanchilelanchile Posts: 566
    edited October 2013
    They do look pristine and good luck w/ them.Not all that familiar to Polk lines but I would have taken copies of all these guys opinions of the high end cost to your "friend" and say look, over in the Polk universe they all are saying your overcharging me for these old speakers .How bout some wiggle room here.Nice looking book enders and not a scratch on them.

    I will keep them for sure! But in the future if the drivers go bad...I will use just the cabinets and get new 8 woofers, tweeters and crossovers. They will be new speakers. so for now I will enjoy them. But in the future (not too far) I will build a Zobel network(impedance compensator) for those woofers.
    Make it simple...Make it better!
  • rooftop59rooftop59 Posts: 6,684
    edited October 2013
    Considering the condition., I think that was a very reasonable price. They are great sounding speakers, and really, what great sounding almost full range bookies can you get for 150? AS for the woofers. I know things go bad but like I said I have had at least 25-30 speakers come through my house and the only time a tweeter or woofer was damaged was in shipping; if it gets to my house safe it works for as long as I keep it, so I thin that you will be fine. Enjoy!
    Living Room 2.1: Dynaudio Contour 1.3mkii; Martin Logan Grotto sub; Musical Fidelity A308; Cambridge Azur 851N
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  • lanchilelanchile Posts: 566
    edited October 2013
    rooftop59 wrote: »
    Considering the condition., I think that was a very reasonable price. They are great sounding speakers, and really, what great sounding almost full range bookies can you get for 150? AS for the woofers. I know things go bad but like I said I have had at least 25-30 speakers come through my house and the only time a tweeter or woofer was damaged was in shipping; if it gets to my house safe it works for as long as I keep it, so I thin that you will be fine. Enjoy!

    Thanks, I agree with you, I have had many speakers too and I have NEVER blown a driver. I know when it is too much for the speakers to handle. even though these speakers are old (time only) they will blow away many new speakers in sound and build quality. One of the old but good speakers that I had was Infinity Beta 20, they sounded very nicely. for their price these are very good speakers. I had some Canton Karat series that were very good but the bass was a little shy and treble was too sharp (fatiguing) to my like. There are many good speakers in the $200-$300 range that will compete with others speakers costing three times more. I remember building the BR-1 from Parts express and they are around $160 now...these speakers are excellent and I will recommend them to everyone looking for small bookshelf and be gentle with your wallet. My best bookshelf speakers for the money are the Polk RTi A1 and the Dayton BR-1 from Part express.

    PS: There are many good ones in the used market now!
    Make it simple...Make it better!
  • lanchilelanchile Posts: 566
    edited October 2013
    DSkip wrote: »
    Right, same here, but I liken the RTx generation to the Magnepan speakers - given enough time, they are going to deteriorate and need to be fixed. I think the issue has to do with the voice coil separating? Don't remember.

    Lanchille, JimAckley has a pair of RT5 and has repaired the same issues for his woofers a handful of times. If you need some pointers, you might shoot him a PM as he'd be more than happy to help.

    Thank you for the tip!!!
    Make it simple...Make it better!
  • lanchilelanchile Posts: 566
    edited October 2013
    I measured the impedance and it shows 4 ohms, How come they said these speakers were 8 ohms? The woofers are 4 ohms too!
    Make it simple...Make it better!
  • lanchilelanchile Posts: 566
    edited October 2013
    Now I am not so happy with the 4 ohms! My amp can push just 8 ohms speakers. I had them at very low volume and the amp got hot...I am thinking of selling them or sell the woofers, tweeters, crossovers and use the cabinets for another project. Too bad I did not sell them to my friend when He asked me to. (I did not know they were 4 ohms)

    PS: if you need the parts or speakers, send me an offer. as you can see. the speakers are in mint condition.
    Make it simple...Make it better!
  • rooftop59rooftop59 Posts: 6,684
    edited October 2013
    You're a strange bird...I drove these with yammie RX v1500 and an HK AVR 630 (avrs made for 8 ohm speakers) and I thought they sounded really nice. I never even had a chance to put an amp on them. What amp are you running? They are pretty efficient and easy to drive IMHO...
    Living Room 2.1: Dynaudio Contour 1.3mkii; Martin Logan Grotto sub; Musical Fidelity A308; Cambridge Azur 851N
    Game Room HT: Denon AVR-X4200w; Definitive Technology SM450; Definitive Technology LCR2000; Definitive Technology Procinema 800; Mirage Nanasats; Sub - HSU VTF-2 MK5
    Master Bedroom
    Cambridge Azur 551r; Definitive Technology StudioMonitor350; ACI Titan Subwoofer; Squeezebox Touch
  • lanchilelanchile Posts: 566
    edited October 2013
    rooftop59 wrote: »
    You're a strange bird...I drove these with yammie RX v1500 and an HK AVR 630 (avrs made for 8 ohm speakers) and I thought they sounded really nice. I never even had a chance to put an amp on them. What amp are you running? They are pretty efficient and easy to drive IMHO...

    it is an old Onkyo.
    Make it simple...Make it better!
  • lanchilelanchile Posts: 566
    edited October 2013
    nbrowser wrote: »
    I almost bought a pair of RT7s today at a second hand store...sounded pretty decent...$100 for the pair.
    These speakers are very good! Today you will not find speakers like them at that price...Too bad I have to sell mines!
    Make it simple...Make it better!
  • tony101010tony101010 Posts: 1
    Hello I have a pair of Polk Audio RT7 31850 Speakers. I need to replace one of the woofers but I can't find the impedance for the woofer. The box says compatible with 8 ohm outputs on the back but the replacements woofers that I find for MW8002 (which is the model number of the woofer) are rated at 4 ohms. I am not sure if I should buy 4 ohms or 8 ohms to replace the woofer as I don't know if the tweeter and woofer are connected and I am not very knowledgeable on serial and parallel connections. Anybody know what I can replace it or both them with?
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