Adire Kit 281 Tweeter polarity issue:

Discussion in 'Home Theater Projects' started by Eric Ha, Feb 1, 2005.

  1. Eric Ha

    Eric Ha Stunt Coordinator

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    For those in the future making Adire 281's, be aware that there is a discrepancy in the manual concerning crossover wiring of the tweeter. The tweeter polarity on the schematic is correct. The tweeter polarity on the crossover layout is incorrect. I do not know why Adire won't fix this on their instructions.

    These tweeters are known to be harsh from the outset, and this fact makes people believe that the crappy sound they are hearing from the mis-wired tweeter is the normal pre break-in sound. I switched the polarity on my tweets last night and wow, what a relief. The speakers sound great now.

    It's difficult enough for newbies such as myself to enter the world of speaker building, let alone build them with incorrect instructions. Just an FYI to help those in the future.
     
  2. Aaron Howell

    Aaron Howell Stunt Coordinator

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    Wasn't this issue addressed in the audioexpress review?
     
  3. Eric Ha

    Eric Ha Stunt Coordinator

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  4. Allen Ross

    Allen Ross Supporting Actor

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    wow, this is the first time i have heard of this. I have the LLC, is there also this error?
     
  5. Eric Ha

    Eric Ha Stunt Coordinator

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    No, the LCC schematics note that the midrange polarity is supposed to be reversed. It is not an error.

    If you wired your midrange without reversing the polarity, you may want to experiment with reversing it .
     
  6. Michael R Price

    Michael R Price Screenwriter

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    Whoops, I saw the question at HTT first. [​IMG]

    It's a good thing the Kit281 uses steep crossovers because the polarity issue would make a much bigger difference otherwise.
     
  7. Eric Ha

    Eric Ha Stunt Coordinator

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  8. Michael R Price

    Michael R Price Screenwriter

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    Use whichever sounds better! The tweeters themselves could even be inconsistent.
     
  9. Eric Ha

    Eric Ha Stunt Coordinator

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    Michael, you may want to switch your polarity and see how it sounds. It's a distinct improvement I think.
     
  10. Michael R Price

    Michael R Price Screenwriter

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    I did try both ways when I was using Adire's crossover. And I have also tried both ways using the Kit281 active crossover. The main benefit of that was to make sure the drivers are acoustically in phase at the crossover point...if you get a lot of cancellation when they're wired backwards, then the alignment is good. Also kind of neat to learn what various frequency response problems sound like. It's a learning experience, to be sure. [​IMG]
     
  11. Eric Ha

    Eric Ha Stunt Coordinator

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    Yes, it is. I'm learning a lot. The speakers sound great now, and they're sounding better all the time.

    I found out today that I didn't have my drivers torqued down tight enough, and was losing a fair amount of mids and lows. I torqued them down tight this morning, and heard a significant improvement, much more than I would imagine. I am now able to run all tone controls flat for the first time in my 40 years! It only took a good bit of work, and a good bit of money!
     
  12. SteveWhitlow

    SteveWhitlow Auditioning

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    I finished up my 281's last night, i plugged them in and turned the volume up very slowly. I let them run for a few hours, varying the volume between low and pretty low. This morning I let them sing quietly for an hour or so and then I started exploring. My initial impression is that they aren't that great! If I have indeed gotten the polarity wrong, what range is affected? Just the highs? (Obviously, tweeters) or mids and highs? The bass seems vitually non-existant (transmission line cabinet). I can hear the 'appropriate' frequencies from each driver and tweeter, but all together, I cannot push them too hard before I hear an audible chirp from one of the cabinets (and believe me, it's at a volume that my previous 6" cheapo speakers could handle in their sleep.) Do they need more break in time or have a crossed the polarity? I was very careful, but I wired them according to the template, not the diagram. Which end of the tweeters do I reverse? The amp end or the speaker end?
     
  13. Michael R Price

    Michael R Price Screenwriter

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    Steve, if the tweeter polarity is reversed on both speakers you will hear hollow sounding midrange. If the tweeter polarity is reversed on only one speaker, you will hear a very strange diffuse sound. I'm afraid there is nothing you can do but play music and wait; the AV8 woofers do take a long time to break in, but your time and effort will be rewarded as the speakers improve. It does sound like a weird problem, though. What does the "audible chirp" sound like?

    I must say I think the Kit281s are pretty good as far as normal speakers go, but I actually haven't listened to the kits in a long time; I disconnected the orignal crossovers after having them for 3 years, and I am now bi-amping using an active crossover. It might be something to consider if you want to use the 281s in a primary music system... but just wait until they're completely broken in before imagining any more improvements. [​IMG]
     
  14. Eric Ha

    Eric Ha Stunt Coordinator

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    Hi Steve,

    I gained midrange after reversing the polarity, but the bass is something else. I felt like you did after a few hours, not enough bass, but I'm very happy now. Here are a few things that I did (and realized) to satisfy my bass needs:

    I had my ports too long, which dropped the tuning frequency and I lost mid-bass. However, the TL set-up like you made is an unknown to me.

    Check your driver screws for tightness. They need to be good and tight, not just o.k. tight.

    As Michael stated, the drivers will continue to loosen up and give a little more bass.

    I would check to make sure that you have ALL of the AV8 drivers wired with the correct polarity. If some are out of phase, there opposing sound waves will cancel each other out, losing mid-bass.

    A VERY important thing to consider is that not all bass is the same. My Polk RTi70's have more mid-bass, but do not go as low, and are not as balanced as the Adires. They sound boomy in comparison. The first day I thought they were better, but as the Adires loosened up, and I performed the other adjustements, I realized that the 281's have a deeper, balanced low-end. The bass is so good that I now turn my SVS sub off when listening to music.

    The only unknown for me is the transmission line cabinet. Try to find feedback on whether it yields good bass. Almost everyone builds the ported version. I did build a sealed center that sounds great. Less bass, but punchier.

    Good luck, and let us know how it works out.
     
  15. Eric Ha

    Eric Ha Stunt Coordinator

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    Here's the response that I just got from Adire:


    Eric,

    Well, just went and camped at the desk of the engineer who did the drawing – the schematic is right, the layout was wrong – it’s now been changed.

    Thanks,

    Adire Tech Support


    If you know someone with Adire 281's, the tweeter polarity is indeed reversed, let 'em know.
     
  16. Andrew Testa

    Andrew Testa Second Unit

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    Arrgh! Not this again!

    So, if one has the Adire-built crossovers, does this mean that the +/- layout on the board is incorrect, or is just the paper layout for those building the crossover themselves incorrect. If the schematic is correct, I suppose I could trace the board to see if it matches, but the crossover is currently buried under a lot of stuffing and wire wrap. I remember when I put mine together (~ 1 year ago) the discussion was that the Audax tweeters had the polarity marked incorrectly on SOME tweeters, and they needed to be tested to make sure they matched the +/- label. Someone help me out here...

    Andy
     

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