Upgrading The Crossovers in My Polk Monitor 10B's

Discussion in 'DIY Corner - Tips & Techniques' started by admin, Jul 7, 2013.

  1. admin Audioholics Robot Staff Member

    admin
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  2. haraldo Audioholic Spartan

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    Good on ya mate :p
  3. CJLA Audiophyte

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    Lack Of Performance?

    Hi Stanton,

    I do like that you explained the 'mechanics' of how to change a cross over but I wish that you had gone into more detail of the performance - or should we say the lack of? What I mean is that, why didn't you do a before and after test & measurements? I would have liked to seen how the new sound compared to the old sound. Did the actual cross over sound different? Even though they may have had the same slopes, maybe you could here a difference, etc. Also with a 30 year old speaker, why wouldn't you just upgrade the whole speaker? Or is that the drivers will actually last for 50 years, but the cross overs are only good for half that? Maybe if you still have the original cross overs you could put it back in to one of the speakers and do a comparison test and measurements? Any feedback would be welcome. Keep up the good work! CJLA
    CJLA,
  4. Stanton Audioholics Contributing Writer

    Stanton
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    The honest answer is I don't have access to such frequency sweep/measurement equipment (or I might have). However, I can offer the following anecdotal evidence. Before I did the XO upgrade, my right front speaker had an occasional mid-range buzz usually triggered by an acoustic guitar (I once found a bad tweeter the same way--guitars are good "stress testers"). That is now completely GONE in addition to a "tighter" bass. Once I noticed that, I rebuilt the XO's on my OTHER pair of 10B's that are used as rear-surrounds. It wasn't mentioned in the article, but I actually ended up rebuilding a total of 4 XO's over a period of 2 weekends.

    Good point that requires some additional background info. It just so happens that Polk drivers/woofers (radiators) were made of a material that doesn't degrade like other speakers do (there's no such thing as "re-coning" a vintage Polk)! Even more amazing is that Polk sells "drop-in" replacement tweeters and drivers (although no XO boards!) if you need one; I replaced my original tweets (many months before the XO rebuild) with the "re-engineered" version as they removed a well-known frequency bump in the 10-12kHz spectrum. While I don't regret replacing the tweets, I notice a much bigger improvement with the XO rebuild (believe it or not the tweets cost less than the XO parts)!
  5. BoredSysAdmin Audioholic Warlord

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    any computer plus this microphone:
    Dayton Audio UMM-6 USB Measurement MicrophoneÂ* 390-808

    plus stand
    plus free REW and you have all minimal necessary speaker measuring equipment which will make articles like this will a lot more "meat" vs fluff like "I noticed an immediate improvement in clarity and “tightness""
    Last edited by a moderator: Oct 19, 2014
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  6. Swerd Audioholic Ninja

    Swerd
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    Where do I begin? This article does show, with photos, how to rebuild a crossover. And it does show that new capacitors can be much larger than the original ones. That’s the good part.

    Now come my complaints.

    (1) SoniCap capacitors are hardly inexpensive. Compare prices of a 12 µF cap from SoniCap and two other well-known metalized polypropylene (MPP) types.

    SoniCap 12 µF $22
    Dayton 12 µF $4.81 (Parts Express)
    Bennic 12 µF $4.90 (Madisound)

    SoniCap is guilty, in my opinion, of selling well-made, but over-priced parts. They claim intangible and unverified benefits from using their products in speaker crossovers.

    There is no evidence that expensive crossover parts, such as those caps sold by SoniCap, change crossover performance in any way. In fact there were efforts of several large groups of DIY speaker builders to verify this several years ago. I was one of the over 40 people present, and the unavoidable conclusion was that high-priced or exotic crossover capacitors made absolutely no audible difference when compared to cheaper MPP or non-polar electrolytic caps in properly designed speaker crossovers.

    (2) Small amounts of data – false conclusions
    There is no evidence that these original caps ever drifted. The 12 µF cap that measured at 13.7 µF may have always been that much out of spec. The writer assumed they were originally in spec, and had drifted over time.

    He further assumed he could hear a difference in sound. Because he did not do this in a blind test, his account is unconvincing. He then went on to claim, without any evidence, that the improved sound was due to the rebuilt crossover.

    It is wrong to present articles like this that suggest, but provide no evidence at all, that replacing crossover capacitors with high-priced capacitors produces an audible improvement.

    I expect better from AudioHolics.
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  7. Stanton Audioholics Contributing Writer

    Stanton
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    I'm not going to get into "degrees of opinion" on what is obviously a subjective subject, but I will clarify a couple of things:

    1) I never said that my choice of capacitors were "inexpensive". I think the phrase I used was "middle of the road" (which to me is neither "cheap" nor "expensive"); in fact, you could spend a LOT more in parts (both R's and C's) for the values used if you chose to include some additional examples.
    2) I think it's safe to say that Polk didn't receive (and use) out-of-spec parts when the speaker was manufactured; I know that we had screening procedures in place to catch (and reject) such things back in my days as a hardware design engineer.

    It's hard to objectively quantify the performance of analog (as opposed to digital) audio components like speakers and some amplifiers, but then again that's what makes this hobby so fun. All I can say is it's good to see folks are reading (and thinking) about what was to me a very enjoyable and rewarding project!
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  8. jinjuku Moderator

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    Be interesting to do another set of X-Overs with Erse Pulse X for about $25 in parts per cabinet and A/B them. Although my experience would tell me the level of the technology that are the transducers would probably be limiting.
  9. Stanton Audioholics Contributing Writer

    Stanton
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    Here's an interesting website comparing many different (audio grade) capacitors: Humble Homemade Hifi
    He rates the SoniCap Gen-I (what I used) much higher than the Erse Pulse X. Good luck figuring out his rating scale, but he's spent much more money and time than I ever will on the subject. Again, a very subjective subject with very subjective results.
  10. jinjuku Moderator

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    I've seen that persons write up before. Without knowing any testing methodology it's just conjecture at best. I give that no more credence than someone that just spent $2K on a power cable and doesn't at least perform a SBT to properly evaluate it.
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  11. Swerd Audioholic Ninja

    Swerd
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    I’ve also seen that web site where some guy has way too much to say about way too many capacitors, all without any credible evidence (other than personal testimony) that different capacitors provide audible differences when used in speaker crossovers. In my opinion, it’s a good example of the kind of misinformation that can rapidly proliferate on the internet.

    Yes, it’s no different than the unfounded claims about audible differences due to power cables or speaker cables.

    I really have no problem if someone installs new crossover capacitors in his speakers, shows photos, and says how happy he is with the results on a public forum like this one. But I do get kind of whiny if someone claims, on a public forum, that the new capacitors caused audible benefits without showing credible evidence to back up that conclusion.
    Last edited: Jul 9, 2013
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  12. gene Audioholics Master Chief Administrator

    gene
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    You can measure the frequency response change in the system, or dissipation factor, ESR, dielectric absorption, etc, in the capacitors, but none of these metrics will determine subjective audibility.

    I think you guys need to just accept that it's an article written by a fellow Audioholic that was looking to improve the sonics of his beloved vintage Polk speakers and offered a way to do that based on a plan that has been validated by other Polk users too. We don't need to measure the hair on a gnats a55 for something like this. Just accept it for what it is or move on. Nothing declarative. It's a tweak and honestly, I enjoy a good audio tweak from time to time without having to analyze every detail of its validity.
    gene,
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  13. GranteedEV Audioholic Ninja

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    If Stanton's speakers sound better after the mod than before then all the better. Having some more controls in place would have improved the writeup though. A long whike ago i mentioned how i was considering doing a cabinet mod to my EMP e55ti speakers to furthrr tighten up their lower mids but one of my reservations was figuring out "how" i could hear -or not hear - the difference without a harman switch machine. Controls aren't easy to come across for DIYers... That's for sure.

    I woukd definitely love one of Frank Van Alstine's switch machines though.
  14. Jose Padron Audiophyte

    Jose Padron
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    Hi, wow this was a great post. I learned a lot! I here have a question... I have a small home theater dvd set, model Sony DAV HDZ273, it came with and it used to have a cheap conventional 3 ohm speakers, very small, but then I bought newest and really bigger speakers for it, the result was great, the new sounds were extremely amazing but, I noticed that the speakers were not working at full frequencies that they can work, I test them in another audio system and they all sounded with great highs and deep clearly basses, so I have been these days looking for information about the crossovers, in the Sony model I cannot change the frequencies digitally then I thought I cloud change them manually by electrical parts, I wanted to ask you if that could be possibly? I thought that if I can set more low frequencies to the new speakers and less highs for the new bass subwoofer that would just give it the touch. Thank you a lot for this post.
  15. ARES24 Full Audioholic

    ARES24
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    Sorry Jose, what you are trying to achieve isn't going to work. Assuming the new speakers are somewhat standard monitors (please provide make and model for more specific info) The Sony unit is not capable of driving the speakers you are trying to hook up. It is possible that driving these speakers with the Sony will ruin the Sony. You are likely to need an AVR to power the speakers properly. If the speakers are decent you will likely not miss out on much anyway. You can then purchase more channels (a sub, rears, etc) as money allows.
  16. Jose Padron Audiophyte

    Jose Padron
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    Hello thanks for your assistance, well the speakers model are in front two Sony ss-d201, center speaker is a LG mds713c. The amplifier within the Sony hdc hdz273 is the 1-875-158-13.
  17. ARES24 Full Audioholic

    ARES24
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    I am sticking with my original suggestion, that system isn't going to support those speakers.
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  18. Walter S Audiophyte

    Walter S
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    I just purchase some Polk Monitor 10B speaker but my crossovers look very different than in the original article. I only have one 12f and one 34f capacitor in my crossover. Anyone run into this before?
  19. TLS Guy Audioholic Overlord

    TLS Guy
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    This is the original crossover.

    [​IMG]

    This is the upgraded DIY crossover.

    [​IMG]
    I think you have the miserable original first order crossovers.

    If you don't want those, then you need to get building.

    I personally doubt those speakers are worth the trouble.
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  20. Stanton Audioholics Contributing Writer

    Stanton
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    I personally have never seen that version of the XO, but if you are absolutely sure it came out of a 10B, then you can build/upgrade to the new version and you will mostly likely hear a big improvement.

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