Crossover for RTA12B

2

Comments

  • pitdogg2pitdogg2 Posts: 12,056
    Yes non directional
  • drumminmandrumminman Posts: 3,362
    edited November 2018
    I have 12C's that came with the SL1000 tweeter. It's pretty much universally reviled around here, but I never heard the harshness so many complain about. I rebuilt the Xovers, built a new wire harness out of OCC copper wire, installed blackhole, epoxied the woofer magnets and replaced the binding posts with Cardas billet copper. Big improvement! Finally decided to replace the SL 1000's with RD-0194's and it took the sound to another level in imaging, smoothness and detail.

    Since the 12B's and C's are supposed to be identical you might want to try 194's.
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
  • CH46ECH46E Posts: 853
    Been a little while, but I'm about to place a order for the 27uf caps and some hardware. Not sure what fasteners to use for the pr and woofers. Will these work? Or do I need a different size? Also while I have them all out I was going to add a little bracing inside. Anything else I should do or order for inside the cabinet? Fiber fill, Black hole? Any kind of sealant? I do have new gasket material for the drivers.

    aeokty7fdpz0.jpg
  • pitdogg2pitdogg2 Posts: 12,056
    no do not use T-nuts Use hurricane nuts. they have no spikes.
  • CH46ECH46E Posts: 853
    edited December 2018
    pitdogg2 wrote: »
    no do not use T-nuts Use hurricane nuts. they have no spikes.

    Would you happen to know what size I need?
    eg0kvuor3rkq.jpg
  • pitdogg2pitdogg2 Posts: 12,056
    edited December 2018
    nope but guessing 8/32
  • #8-32 hurricane nuts. Parts express has those. Parts express doesnt carry the cap screw you need. I used fastenal as suggested by some users on here. I used #8-32 by 1 inch long.
    Monitor 4.6, 5jr, 5, 7, 10, 11. RTA 8TL. RTA 11T. SDA 2B.
  • CH46ECH46E Posts: 853
    Thanks guys!
  • FaustinFaustin Posts: 804
    You may want to consider a piece of BlackHole 5 or equivalent behind the mid woofers.
  • CH46ECH46E Posts: 853
    edited December 2018
    Faustin wrote: »
    You may want to consider a piece of BlackHole 5 or equivalent behind the mid woofers.

    How large of a piece please? I'm guessing enough to cover the back of the upper 1/4 to 1/3 of the cabinet?
  • pitdogg2pitdogg2 Posts: 12,056
    CH46E wrote: »
    Faustin wrote: »
    You may want to consider a piece of BlackHole 5 or equivalent behind the mid woofers.

    How large of a piece please? I'm guessing enough to cover the back of the upper 1/4 to 1/3 of the cabinet?

    Just enough directly behind the woofers only.
    You're going to buy a bigger piece than you need but that's just how it works. Blackhole 5 has changed and ridiculous to find now. Parts express has something similar get the thickest to match up to BH5.
  • CH46ECH46E Posts: 853
    33tj66em533c.jpg
    After a little cleaning. 56yiudg29klq.jpg
  • CH46ECH46E Posts: 853
    Ok so.... the red wire replaced a white wire. I replaced both tweeter leads with some excess AQ wire I had. Now because I'm always confused with these speakers im not 100% sure what goes where. My peerless oem tweeter has a red washer under one terminal. That is positive right? And if so would in this case use my red wire right? Or does this RTA12B do something different?
    I think why I'm always confused is because the tweeters have a small lead soldered to them (was there when I got them from a member here) and the black wire is on the red lead. So its throwing me off.


    gzj0e19rfjs5.jpg

  • CH46ECH46E Posts: 853
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  • CH46ECH46E Posts: 853
    After looking at the schematic for the 12b I see the white wire (red in my case) is in fact the positive lead. So like my 194s is the red tab on the tweeter the positive? Regardless of someone putting a black wire on the red tab.
  • pitdogg2pitdogg2 Posts: 12,056
    F1nut wrote: »
    Black or blue is positive.
    White or green is negative.

    And RTA12 tweeter is wired out of phase because the signal is reversed through the XO. So hooking the positive wire to negetive on the tweeter puts it back into correct phase.
  • CH46ECH46E Posts: 853
    Will do that now as I'm listening to them already. Let's see if I notice a diff.
  • CH46ECH46E Posts: 853
    Listening to "Outside" by the Fixx on DVD-Audio and it sounds pretty good.

    I think..... it does sound more natural wiring them out of phase. Thanks! I'm may try some back and forth before I solder them in place.
  • FaustinFaustin Posts: 804
    "After looking at the schematic for the 12b I see the white wire (red in my case) is in fact the positive lead. So like my 194s is the red tab on the tweeter the positive? Regardless of someone putting a black wire on the red tab."

    You are correct in regards to the schematic. On the 12b and c the white lead is positive. It is confusing because on the monitor series the black lead is positive. You stated that there is a "black lead" on your Peerless tweeter. Was it soldered that way on your RTA 12? When I had my c/o's rebuilt on my 12b's, I hooked the tweeters up with the black lead on positive and the white on negative. They didn't sound right. After looking at the schematic I switched the leads and they opened up. Also, mine where not soldered. They have crimped connector ends. In regards to the Blackhole 5, like Pitdogg stated, just a rectangular piece behind the mid woofers. Something like 8" by 13".
  • CH46ECH46E Posts: 853
    My peerless are not the originals that came with these. They are the right ones, but nor the originals. Who know what they were in before I got them. (The peerless)

    The leads were already soldered to the tweeters in the fashion shown in the photo.

    Just to clarify please. The red tab on the peerless is the positive lead???
  • FaustinFaustin Posts: 804
    The red tab is the positive on the Peerless. My guess is that yours came out of a monitor 7, 10, or ? You can solder the leads or use the crimp connectors. And for what it's worth, my 12's sounded dramatically different at around 225 hours. A lot of people pooh pooh the idea of "burn in time", but the change was dramatic. In fact, probably the most dramatic change I had ever heard of a speaker "burning in".
    I was initially disappointed with them. I had them hooked up to a Yamaha receiver at the time to give them burn in time. I also had my 10's hooked up and could A - B them to compare. Initially the 10's kicked their butt. I even had a friend ask me what I had done to the 12'2 to get them to sound better. He had heard them initially and then again after 225 hours or so.

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  • pitdogg2pitdogg2 Posts: 12,056
    edited December 2018
    CH46E wrote: »
    Listening to "Outside" by the Fixx on DVD-Audio and it sounds pretty good.

    I think..... it does sound more natural wiring them out of phase. Thanks! I'm may try some back and forth before I solder them in place.

    personally I'd use quick connects instead
  • CH46ECH46E Posts: 853
    Any suggestions?

    I'm about to place an order with Parts Express for a few things. I have the rest of the caps and have that Black Hole 5 "like" stuff in their thickest option for behind the drivers and or upper 1/3 of the cabinet. I have the hurricane nuts and screws. I have new speaker gasket. Is there anything else I should be doing to the internal cabinet? (I will be adding 2 small braces while i have the PR out) Is there anything else I should be ordering? Would like to make 1 order for the discounts and free shipping.

    Should i bother with replacing the internal wiring?

    Should I buy and replace the polyfill/fiberglass stuffing?

    Should I go ahead and find a sealant to make sure all the internal joints are sealed?


    I want new binding posts but have no idea how to install them on the oem cup. I dont want to crack the cup and want to make sure I have a great airtight seal.

    I will be using the quick disconnects for the tweeters for sure.

    One more question please. Would mass loading the PR help? Would it help with bass response? Maybe increase power handling on the drivers and or provide more control of the drivers?

    Thanks everyone for all the feedback thus far!
    Chris
  • FestYboyFestYboy Posts: 3,105
    Don't touch the back of the PRs, if the need for experimentation arises, Polk made a few 12" PRs in different tunings that your can try first, some of which are set up for tuning with extra washers. Another non permanent option is clay, but that will likely ony work well with the plastic faced PRs.
  • CH46ECH46E Posts: 853
    edited December 2018
    FestYboy wrote: »
    Don't touch the back of the PRs, if the need for experimentation arises, Polk made a few 12" PRs in different tunings that your can try first, some of which are set up for tuning with extra washers. Another non permanent option is clay, but that will likely ony work well with the plastic faced PRs.

    Ok, good to in know. Thanks!
  • pitdogg2pitdogg2 Posts: 12,056
    Dude you are WAY over thinking a lot of this. Yes seal the cabinets with powergrab if needed. Too much dacron or blackhole will SUCK the life right out of those speakers.
    Armacell pipe wrap you can cut to fit the binding post cup and it will be air tight without over tighting to the point of breaking the cup.
  • FaustinFaustin Posts: 804
    Leave/use the dampning material that is already there. Like I indicated before just put a rectangular piece of BH5 behind the mid woofers. I think if you cover the upper third of the cabinet you will kill/diminish the bass. If you want to upgrade the internal wiring, go for it. Easy to do. Binding posts are easy to do as well. Look for some gold plated copper posts on the bay. The originals are more than likely "sealed" with hot glue. I have had good success removing the glue by just carefully prying it up a little at a time. Use a small screw driver, small wood chisel etc. Some people heat it, use solvent etc to remove it, but I never had to do that on the Polks I have redone. Once the glue is removed the wires should be screwed to the posts. See pictures. Once the new ones are installed you can cover them with Power Grab (the same thing used to seal the cabinet joints) or hot glue to seal things up.
  • pitdogg2pitdogg2 Posts: 12,056
    Do not cover the new binding post with powergrab. Use hot melt just like Polk did.

    Just pulling it up with needle nosed pliers will work. I have never had problems myself either, but if you do 91% alcohol will get it to release and wipes away and evaporates.
    Hot melt glue seals it air tight and if you ever need to remove it for any reason it will be a ton easier than chipping away that powergrab construction adhesive. In the long run powergrab adhesive may have a bad reaction with the wire or binding post. One thing we all know for sure is that the hot melt glue is very safe in that regard.

    Sonic craft sells Cardas binding posts cheaper than anyone else and have a great selection.
  • westmassguywestmassguy Posts: 6,217
    Faustin wrote: »
    The red tab is the positive on the Peerless. My guess is that yours came out of a monitor 7, 10, or ? You can solder the leads or use the crimp connectors. And for what it's worth, my 12's sounded dramatically different at around 225 hours. A lot of people pooh pooh the idea of "burn in time", but the change was dramatic. In fact, probably the most dramatic change I had ever heard of a speaker "burning in".
    I was initially disappointed with them. I had them hooked up to a Yamaha receiver at the time to give them burn in time. I also had my 10's hooked up and could A - B them to compare. Initially the 10's kicked their butt. I even had a friend ask me what I had done to the 12'2 to get them to sound better. He had heard them initially and then again after 225 hours or so.

    7u17hms3wi4j.jpg
    bi9unyf4ctfk.jpg
    npayjt9mpwmf.jpg

    Wow, just realized I did your crossovers forever ago Bruce.

    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
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    Den:
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    dhsspeakerservice.com/
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