Rta 12c

reeltrouble1
reeltrouble1 Posts: 9,312
edited October 2006 in Vintage Speakers
Another nice vintage set, a pair of POLK RTA 12C comes into the RT1 family, these are very fine looking, the past care taken with them is obvious, this set is for my older son who has begun his own path to audio nervana.

A big thank you to Doro for holding these till he could pick them up along with treating my boys so well on their visit. They were also very impressed with the SVS demo Mark.

RT1
Post edited by reeltrouble1 on
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited January 2005
    And another of the speaker array:

    Had a quick listen and was impressed right off with the imaging.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    Glad you guys are happy..those have been through a couple "family" members hands, so take care of them. Just passing on some goodwill.

    Here are the spec's per you request:

    RTA12C

    39H x 16W x 11 7/8D
    75 Lbs.
    17Hz - 26,000Khz
    10 - 500 WPC
    4 Ohm
    92dB Efficient
    118dB Max Output

    It's a great speaker, that why I bought another....wink wink.

    I cleaned yours up real good prior to being boxed again, and everything was treated with CAIG products. I also repaired a broken grill mount with a damn near identical replacement part that I sourced from PE. Can you find the odd man out?

    Your boys were very cordial and nice to chat with, sorry they couldn't stay longer, but the road was calling. Thanks so much for the Jackets and T-Shirt.

    I tried to kill them with the SVS.

    I was lax in ordering my stuff for you, so give me a week or so, and it will be at your door.
    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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  • Tour2ma
    Tour2ma Posts: 10,177
    edited January 2005
    Most unusual speaker in the Polk family...
    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
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • TroyD
    TroyD Posts: 13,083
    edited January 2005
    Man, those things have made the rounds up the I-95 corridor....


    Enjoy 'em Ted !

    BDT
    I plan for the future. - F1Nut
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  • George Grand
    George Grand Posts: 12,258
    edited January 2005
    Too bad I never got to meet the original owner.

    George Grand (of the Jersey Grands)
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited January 2005
    Certainly a bit different design than Polk's usual, however, drivers are familiar. What is the idea with the tweeter electronics?

    As far as 95, well, they will be headed back up to New Jersey later this month. Will end up around Toms River.

    RT1
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  • RuSsMaN
    RuSsMaN Posts: 17,986
    edited January 2005
    Time alignment big poppa, time alignment. That, and the crossover is a little over-built (a good thing), compared to the rest of the series.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    Real Time Array. It's the only RTA that really follows that idea IMO.

    It aligns the voicecoils on the drivers so that, in theory, all the frequencies should reach the listener at the same time. High frequencies move faster than low frequencies. It results in better imaging and soundstage.

    Another example....The stands for the Mon10..7 and 5 all have an upward tilt, so as to create in Russmans' words....a poor man's time alignment.

    I have a pair of Mission Argonauts and B&W DM550 that both follow a time alignment idea as well. The Mission is more traditional, while the B&W is electronic(crossover related).
    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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  • RuSsMaN
    RuSsMaN Posts: 17,986
    edited January 2005
    Hit the nail on the head Doro, short of the 'speed' statement.

    The speed of sound, is this speed of sound, regardless of frequency. What is it, 720 mph at sea level, 650 mph at 40,000 ft? Now the size of the wave, that's another story.

    What polk has done in the 12's (and accomplished with the 7's and 10's on stands as you mentioned), is align the voicecoil of the tweeter, with the voicecoil of the woofers.

    Since the VC is the source of the sound, and woofers are typically 'deeper' than tweeters, setting the tweeter BACK to align (on a vertical plane) the voicecoils helps insure that the sound reaches the listener at the same time, from all the active drivers.

    I think in the other RTA speakers, they probably used resistors to 'delay' the tweeter slightly, to compensate for the coils not being aligned. At least thats all I can figure.

    Cheers,
    Russ
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    There is a difference in frequency rates, and the effects of those rates on the conditions around or upon with which it travels.

    Whether you subscribe to the theory that this is audible is another thing, I personally don't care either way, it's just another application to me.

    If we could look at the schematics maybe that would determine the Bimmer effect.

    Trivia question:

    Why is an AM transmission tower warm or even hot to the touch compared to FM?
    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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  • HBombToo
    HBombToo Posts: 5,256
    edited January 2005
    Originally posted by RuSsMaN


    I think in the other RTA speakers, they probably used resistors to 'delay' the tweeter slightly, to compensate for the coils not being aligned. At least thats all I can figure.

    Cheers,
    Russ

    This does not read right to me... true resistors should not change the timing of a circuit unless there are of course inductive or capacitive effects from a non perfect resistor(but now we are talking phase). I'm not even certain if I understand the relation between phase and coherence.... maybe someone can take charge here?

    HBomb
    ***WAREMTAE***
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  • HBombToo
    HBombToo Posts: 5,256
    edited January 2005
    Originally posted by dorokusai

    Why is an AM transmission tower warm or even hot to the touch compared to FM?

    because it is the tower that radiates not an antenna on a mast that radiates. That is the reason for all the ceramic isolation on the guy wires....

    again when there is conduction there is resistance and the loss in power is dissapated as heat. "conservation of energy and mass ;) "

    HBomb
    ***WAREMTAE***
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  • George Grand
    George Grand Posts: 12,258
    edited January 2005
    Ending up near Toms River is close to where the journey started. I found that pair at the McGuire AFB Thrift Shop!

    George Grand (of the Jersey Grands)
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited January 2005
    Damm, I love learning about this sheeet. I had figured some of the crossover on the top of the cabinet although as said its over built compared to most things I have seen/taken apart. I thought I might try to launch something with it, yes just kidding. The setting back of the tweeter for alignment is most interesting, I did not catch that and yea, it would seem to be a better method than delaying through resistors or some other info. I will relay the lesson to junior. Thanks for the help guys.

    GG--Guess they have come just about full circle then. Jr. has been known to pawn a few things in his life, if you see them again well now that would be something, however, he has been advised of pawning consequences, he did though buy these, hell should have, he only 30 friggen years old.

    I have spent a bit of time at FT. Dix myself.

    RT1
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  • RuSsMaN
    RuSsMaN Posts: 17,986
    edited January 2005
    Originally posted by HBombToo
    This does not read right to me... true resistors should not change the timing of a circuit unless there are of course inductive or capacitive effects from a non perfect resistor(but now we are talking phase).

    I only mention it because I have seen it in some high-end designs. For example, if you have a front firing AND rear firing driver, placing a resistor across the pos/neg terminals of the rear driver can cause a slight delay, thus keeping 'timing' more correct with when the sound from both drivers reaches the listener (and still maintain absolute phase).

    I haven't seen it on tweeters, but certainly on woofers. Now as to the values of the resistors, I have no idea where to start.

    Cheers,
    Russ
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    Is this what DefTech could be doing? or is doing?
    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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  • Tour2ma
    Tour2ma Posts: 10,177
    edited January 2005
    It is important to note that the sound speed in air is determined by the air itself. It is not dependent upon the sound amplitude, frequency or wavelength.

    Also interesting read on cross-over design impact on time alignment. Bottom line appears to be that higher order cross-overs induce time delays...
    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
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • RuSsMaN
    RuSsMaN Posts: 17,986
    edited January 2005
    Geocities? Thanks Tour, that's a reputable, noteworthy source. I'd put em right up there with the New York Times.

    ;)

    That's interesting that the speed of sound has to do with the atmospheric condition, the air itself. I always though it was 'pressure' related, hence the altitude comment. So does this mean after a few bongs hits, and the air in my room is filled with smoke, my speakers will sound different?

    Cheers,
    Russ
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • hoosier21
    hoosier21 Posts: 4,413
    edited January 2005
    Originally posted by RuSsMaN
    So does this mean after a few bongs hits, and the air in my room is filled with smoke, my speakers will sound different?

    Cheers,
    Russ

    yes they will,

    but with the sound of a 1lb bag of fried pork skins being destroyed by a munchie fit, will mask any improvements offered by the smoke
    Dodd - Battery Preamp
    Monarchy Audio SE100 Delux - mono power amps
    Sony DVP-NS999ES - SACD player
    ADS 1230 - Polk SDA 2B
    DIY Stereo Subwoofer towers w/(4) 12 drivers each
    Crown K1 - Subwoofer amp
    Outlaw ICBM - crossover
    Beringher BFD - sub eq

    Where is the remote? Where is the $%#$% remote!

    "I've always been mad, I know I've been mad, like the most of us have...very hard to explain why you're mad, even if you're not mad..."
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  • VR3
    VR3 Posts: 28,774
    edited January 2005
    Originally posted by dorokusai
    Is this what DefTech could be doing? or is doing?

    From what I know, that is what they do...
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited January 2005
    Originally posted by RuSsMaN
    Geocities? Thanks Tour, that's a reputable, noteworthy source. I'd put em right up there with the New York Times.
    Just one of many hits on "speaker time alignment".... and this one had pretty graphs... :)
    At least you didn't put them at CBS Evening News level...

    And since when do you smoke in the house???

    ummmmmm... pork rinds....
    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
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • George Grand
    George Grand Posts: 12,258
    edited January 2005
    The speed of sound varies as to the density of air molecules. Higher up, less molecules, higher speed of sound. Lower down, more molecules, lower speed of sound.

    The density of the molecules at lower altitudes is more resistant to sound waves as well as aircraft movement.

    You guys really can't just enjoy the sound of a freakin' pair of speakers can you?

    George Grand (of the Jersey Grands)
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  • Strong Bad
    Strong Bad Posts: 4,278
    edited January 2005
    No sh** George!

    These guys are frying my brain with all this time alignment and speed of sound chatter!

    Just listen and hush. :D


    John
    No excuses!
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    It was originally, simply an basic explanation of Polk's application in regards to the RTA12....the rest is just for information purposes.

    I do enjoy them, and alot of other things...not all of us are SDA slaves.
    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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  • Toxis
    Toxis Posts: 5,116
    edited January 2005
    So how would you describe the sound on the RTA12's? Would you say they'd be better for a certain style of music? What are you running them with? I'm only asking because a local guy has a set for sale, but he wants WAY to much for them ($470/pr.). If they're really that good, I might make an offer.
    Never kick a fresh **** on a hot day.

    Home Setup: Sony VPL-VW85 Projo, 92" Stewart Firehawk, Pioneer Elite SC-65, PS3, RTi12 fronts, CSi5, FXi6 rears, RTi6 surround backs, RTi4 height, MFW-15 Subwoofer.

    Car Setup: OEM Radio, RF 360.2v2, Polk SR6500 quad amped off 4 Xtant 1.1 100w mono amps, Xtant 6.1 to run an eD 13av.2, all Stinger wiring and Raammat deadener.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    They aren't $470/pr. good.
    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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  • Toxis
    Toxis Posts: 5,116
    edited January 2005
    that's fine, but again, how would you describe the sound. I'll probably offer him like $250-275...
    Never kick a fresh **** on a hot day.

    Home Setup: Sony VPL-VW85 Projo, 92" Stewart Firehawk, Pioneer Elite SC-65, PS3, RTi12 fronts, CSi5, FXi6 rears, RTi6 surround backs, RTi4 height, MFW-15 Subwoofer.

    Car Setup: OEM Radio, RF 360.2v2, Polk SR6500 quad amped off 4 Xtant 1.1 100w mono amps, Xtant 6.1 to run an eD 13av.2, all Stinger wiring and Raammat deadener.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    I think they have a very open soundstage, beyond the physical design.

    It simply feels larger to me....like it is more than a box radiating sound. The bass extension is better than a Mon10, easily, and the high end follows with the imaging....it's not box like anymore. I keep thinking "open"....but that's just my opinion, and on my junk.

    It's the only RTA, I would even think about owning, and I do. It's the only one that is true to the definition IMO. The other RTA's are nothing special.....just speakers.
    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 January 2005
    Q: So how would you describe the sound on the RTA12's?....
    A: Pointed towards a 45 degree listening angle, the stage seems to me to be painted across the wall both between and behind them, almost as good as my old 2.3TL's. I count the hours until I can press my power button ON. The sound is very open, almost like a laboratory test speaker for the SDA series.

    Q: Would you say they'd be better for a certain style of music? What are you running them with?
    A: Euro 2+ hour Goa/Techno/Schranz mixes, Blues, some Classical.

    Q: I'm only asking because a local guy has a set for sale, but he wants WAY to much for them ($470/pr.). If they're really that good, I might make an offer.
    A: Listen to them, if you like make an offer of $200 or less. If he wants more walk away (but leave your telephone number). $200 or less is the average selling price.

    GOOD LUCK!

    P.S. Bass response is a little weak imho. You may 'feel' the need to add a sub-woofer. Even with my Polk psw550, I don't 'feel' as much bass as that from my old sda 2.3TL's.
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  • dorokusai
    dorokusai Posts: 25,577
    edited January 2005
    Bass response "weak"? I love the 2.3TL comparison....that makes alot of sense.
    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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