L12b speakers

stingray
stingray Posts: 7
edited March 2005 in Troubleshooting
bought a pair off ebay ,, was told there missing the covers for the crossovers and tweeter,, does anyone have pics or can tell me if they actually came with them and if i can buy them ?? got any of these covers ?
Post edited by stingray on
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  • F1nut
    F1nut Posts: 50,561
    edited March 2005
    Those are not L12B's, rather they are RTA12B's. If you do a search for "RTA12" you'll find some pictures.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • stingray
    stingray Posts: 7
    edited March 2005
    thanks for your help,, i'm ganna check that out right now,, maybe i can even find the covers for sale ?
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  • dorokusai
    dorokusai Posts: 25,577
    edited March 2005
    Originally posted by stingray
    thanks for your help,, i'm ganna check that out right now,, maybe i can even find the covers for sale ?

    I seriously doubt it. I have a pair of these, and can measure them if you want, but don't be in a hurry. Perhaps someone else has a pair that is not packed....PM Reeltrouble1.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    Congratulations stingray. These will suck a good bit of power, so the stronger the amp you can use will give better (and deeper) results. A modern day 100 watt audio/video receiver will make these sound weaker than they really are. I have seen different ratings for this speaker but ballpark is 250 watts RMS.

    I have attached only close-up pictures as a search here on the forum for "RTA12" will bring up more full size pictures. The guide pins are 10 1/8" apart measured from their center.

    Here is the manual (may be a slightly different version but it is the same model):
    http://www.polkaudio.com/downloads/manuals/home/12CManual.pdf
    http://www.polkaudio.com/downloads/manuals/home/12CManual.zip
    01.jpg 144.7K
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    side view height & width

    note: the top cover is the same width as the cabinet.
    02.jpg 87.4K
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    The arrow shape points towards the front and the base is black painted MDF with two holes for the metal guide pins. There is a small piece of dampening fiber material located inside the center at the front.

    To clarify, the back to front base (wood) is 12 inches however the sides are acrylic and rest on top of the wood base. The back to front sides measure 11 inches.
    03.jpg 86.6K
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    The sides and top are made from pieces of acrylic screwed together in pre-drilled holes. Nothing is on the front except for grille cloth.
    A few more shots of the front dampening fiber material.
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    guide pin height and width:
    05.jpg 119.9K
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    That circuit board really needs a spring cleaning.
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    Again, the guide pins are 10 1/8" apart measured from their center.
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  • dorokusai
    dorokusai Posts: 25,577
    edited March 2005
    Great post Polk65, you certainly have a rare pair.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • stingray
    stingray Posts: 7
    edited March 2005
    wow,, thanks for all the pics,, dont think its anything i wanna try and build,, but at least now i know what they actually look like,, hopefully i can find some for sale,, i was told it doesn't effect the sound quality with the covers off ? i found that wierd ,i thought all tweeters needed some type of inclosure,, my tweeters are different then yours in the pic,,yours look like 4'' tall by 3'' wide ,, mine are like 3'' tall by 4'' wide,, kinda like if you layed yours sideways,, probobly an older model? thanks for all your help
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    Thanks doro, I love listening to them daily :)

    Stingray, a college wood shop student should be able to make these covers for you. If you decide to do this, ask and someone or myself will provide more detailed measurements.

    I bought my RTA12's about 3 months ago, and I prefer the top covers off. They sound more brighter and wider to me this way. It's all up to your room, and what your ears like.

    There are several versions of the RTA12 each with different configurations. As far as I am aware of, there are the RTA12, RTA12a, RTA12b, and RTA12c. Tweeter configuration, crossovers, and with or without cabinet stands are the most common variations. Early RTA12's had a dark gray circle of thick paper around the 6 1/2" drivers. I suppose your cabinets will say L12b (left) and R12b (right) meaning that you have the RTA12b version.

    There are also different styles of top covers for the RTA12's but since yours have the metal guide pins (like mine) the cover in my pictures will probably be like the ones that came on yours.

    Search the Polk Audio forum with these different words and you will find some previous discussions related to your new speakers: "rta12" "rta12's" "rta12a" "rta12b" "rta12c".

    What kind of amplifier or receiver are you going to use with these?
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  • stingray
    stingray Posts: 7
    edited March 2005
    right now all i have for power is a 3 year old onkyo surround reciever,,rated at 110 watts,, before i bought the polks i had a 15'' audiosource powered sub and pinnacle bookshelf speakers on stands,,,,,hopefully the onkyo will be enough, i also drove a pair of floor standing klipsch, with dual 10'' mid/bass /horn loaded tweeters,,but those were efficient speakers,, 93 i think they were,anyway ,i'll do that search,,thanks for your help !!!
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    The temptation may exist to raise your surround receiver's volume with these. They have a non-powered 12" passive radiator driven by two 6 1/2" mid-woofers so to get these sounding loud, you will need a high current amp. Be careful going above 3/4 level of volume on your surround receiver as damage can occur to your speakers if the receiver's amp is driven too hard. Same goes for the bass/treble/loudness controls, if you choose to use these be careful. I believe these are rated at 92, 4 ohms, 250 watts per channel.

    I'm new to this forum and my advice is from reading what more seasoned members here have said in other messages and my experience with the RTA12. If someone sees something wrong with my advice, they will chime in with a comment.

    When are your speakers due for delivery?
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  • stingray
    stingray Posts: 7
    edited March 2005
    delivery ? thats a good question,its been a week and i bought these from a stereo store that sells used items on ebay,,he said he's still looking for appropriate boxes to pack them,,,jeez,,if i was selling something on ebay as big as these speakers are ,i think i would have had boxes before putting them on ebay and then making the buyer wait a week and still not have boxes yet,,,hehe,,i'm glad i'm patient,,,haha,, the pic's you posted are excellent and should be good enough to build the covers myself,,last i knew radio shack sold grill cloth,,hopefully matches or i could dye to match,,any other suggestions on that grill cloth ?
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    If the seller has still not shipped yet, you might give them a call or email to let them know that the top crossover and tweeter assemblies can be easily removed from the cabinets. There are thumbscrews on each side, and a quick connect socket for the wires at the rear. With no top covers, this would make it easier for them to ship since the tops would be flat.

    Considering the amount of speakers and boxes they have in their store behind your speakers, they suck.

    For grille cloth, check out item #4 in the list of materials used in the first message of the thread "Improvements to the SDA SRS": http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=19053

    or http://www.PartsExpress.com
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  • stingray
    stingray Posts: 7
    edited March 2005
    wow,,thanks again,i saved both in my favorites,, i think i'm going to look for a used adcom amp ,like 200 watts per channel,, that should be plenty to drive my polks,,,,lol
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited March 2005
    Originally posted by Polk65
    the top crossover and tweeter assemblies can be easily removed from the cabinets.
    Not only can, but should be removed and packed separately...

    P65,
    Are your caps original, or home made?

    Wondering 'cause while mine are dimensionally similar, that's about it... no acrylic panels... just a frame and fabric.
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner
    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
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  • Polk65
    Polk65 Posts: 1,405
    edited March 2005
    Good point. The top covers actually shipped in a seperate box and assembly instructions are in the manual. I saw a photo somewhere of a pair of RTA12 cabinet boxes and the top cover boxes next to them but cannot find it.

    Are these oem covers? I'm not sure but the bonus is that they will never sag. My question about if they are original remains unanswered in another RTA12 thread a few weeks ago: http://clubpolk.polkaudio.com/forum/showthread.php?threadid=26720#post272643

    They image very well and if they are home made, I have no access to another pair (such as the type with rails) to compare them to. Perhaps someone can ask Ken the next time they call, I currently have no other questions to bother him with.
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