Building a pair of Polk Monitor 10's

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Comments

  • Toolfan66Toolfan66 Posts: 14,293
    edited March 2016
    I find it funny how it can be posted about Polk speakers that Matt sold to many people, and according to some here are not up to par with other speakers that he designed and sold as well..

    Sometimes I think just having fun with a project gets lost in the "it needs to be this or it's going to s.u.c.k and not be this" "you would be better off just buying this"

    It's sad really..

    Obviously everything Matt, and Polk in general didn't, and don't put out speakers that are up to some of your standards, are you posting or emailing them on how they should build a speaker? I didn't think so.. The funnier thing is there are many people out there enjoying those speakers that don't fit "your standards"..

    Let the guy have fun, give him some pointers, and help him along, you never know they might just sound fantastic, and better yet, makes him happy with what he created...

  • Toolfan66Toolfan66 Posts: 14,293
    With that said, please don't use plywood!! B)
  • DSkipDSkip Posts: 16,288
    It's not sad. It's an opportunity to learn more about audio and why things work the way they do. Everything accounts to the sound you get, so if he expects a Monitor 10 clone and went about it the way he started, it wouldn't have been. He could have stuck with the original design and still have enjoyed them, but they could have been way off as well. With the time investment and expectations he had, I think this has been a very informative and productive thread.

    Keep on rockin' Will. I'm interested to see what direction this takes because you've taken more interest in the hobby and stereo reproduction. It's going to be exciting now no matter what the outcome is.
  • willwillywillwilly Posts: 185
    Toolfan66 wrote: »
    With that said, please don't use plywood!! B)

    MDF it is! How can I argue with that! When I get to that point, I'm sure I'll have more questions!

    Thanks such for your sensibly words! I was getting close to chucking it all and buying some earphones... :#

    But I'm not so easily swayed...


    Will I am
  • willwillywillwilly Posts: 185
    Wow, no pressure here.

    I'm sticking to my guns and building a clone set of 10's with real wood veneer, maybe Cherry, maybe Walnut.

    If I duplicate internal dimensions, Polk components and correct baffling, one should expect very simular results. I'll know when I place them next to my fives.

    Thanks again everyone! Now for a little less talk and more work, with pictures.
    Will I am
  • willwillywillwilly Posts: 185
    DSkip wrote: »
    With the time investment and expectations he had, I think this has been a very informative and productive.

    It has! Look at it this way, I have a whole set of cheap drivers and tweeters for the next project!
    Will I am
  • Toolfan66Toolfan66 Posts: 14,293
    Skip, I agree, but you know as well as I do when someone starts a project like this, they usually get torn down before they get started..

    I mean really, we are talking about Monitor 10's here, not someone that wants to clone some Ushers, or Sonus Faber's..

    We're talking about a set of 30 year old speakers, that apparently Matt designed and are not as good as some of his other designs but sold to the general public anyways...

    I would bet a million dollars that if someone built a set of monitor 10's or even set of 7's cabinets, built them to exact specs, used the same wood, and put the same drivers, x overs, and tweeters, there would be a few here saying they can here a difference, and the originals are better, yet Matt/Polk was known for using up older stock parts as they moved to the new line of speakers they were pushing..

    Again, we are talking about a guy that wants to build a set of his own monitor 10's, it's not like he wants to reinvent the SDA technology...
  • deucekazoodeucekazoo Posts: 146
    Toolfan66 wrote: »
    With that said, please don't use plywood!! B)

    Toolfan, I just need to know, why so against plywood?
    Not the basic hardware store stuff, we are talking Baltic birch here.
    I made a lot of speakers out of Baltic birch, great to work with. The only thing I would use MDF for is table tops and subs. Don't care for the stuff.
    Polk S10, S8, S4
    Polk RT8
    Polk Monitor 7s
    Working on getting SDAs
  • willwillywillwilly Posts: 185
    edited March 2016
    So I'm starting to do preliminary design work on the cabinet. Polk specifications have the exterior dimensions as 28"x16"x11.5" I'm using a 3/4" wall thickness and 1" back and front. I may need to stretch the 11.5" depth to 12.5" since I'm pretty sure Monitor 10's were 3/4" wall thickness all the way around.

    If one of your has a 10 cabinet you can measure interior dimension exactly, I will duplicate volume. I'm not sure if I will have to compensate for the volume lost on filling the corners?

    Your thoughts?
    ly8qqfahq7lk.jpg
    Post edited by willwilly on
    Will I am
  • willwillywillwilly Posts: 185
    edited March 2016
    Here is the complete unit. I'm showing the back side of the front. I plan on rounding the inside ports.

    Again I don't have the exact locations of the PR, driver and Woofers. If someone can measure theirs I can make changes.

    The front and back are MDF 1" construction. Both the front and back exterior will be laminated with matt black poly textured sheets. Walls are 3/4" walnut laminated.

    I'm not sure if I need to consider having the corners between the front face and sides rounded. Still contemplating.

    Any help you can give on actual measurements would be great be great.

    gagxbzyg0db4.jpg
    Will I am
  • voltzvoltz Posts: 5,303
    I built a pair of Full range crossover less speakers using a kit from Madisounds that uses Baltic birch plywood and I think they sound pretty good for what they are...
    vy8wm97gmpqb.jpg

    poc65ix4ig11.jpg
    rfrukkg3vuw9.jpg
    2 ch- Polk CRS+ * Vincent SA-31MK Preamp * Vincent Sp-331 Amp * Marantz SA8005 SACD * Project Xperience Classic TT * Sumiko Blue Point #2 MC cartridge

    HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
  • voltzvoltz Posts: 5,303
    edited March 2016
    So have fun with it!
    and BTW
    here is a pair of Stirling Broadcast LS35a that uses 9mm birch plywood :)
    http://store.acousticsounds.com/d/88073/Stirling_Broadcast-LS35a_V2_Speakers-Speakers
    2 ch- Polk CRS+ * Vincent SA-31MK Preamp * Vincent Sp-331 Amp * Marantz SA8005 SACD * Project Xperience Classic TT * Sumiko Blue Point #2 MC cartridge

    HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
  • willwillywillwilly Posts: 185
    edited March 2016
    Thanks for sharing. I have seen many of these kits and they look like an interesting project.

    The more research I do, the more I discover MDF will produce the best results for the cost. I have seen very pricey solid wood speakers but I'm sure the manufactorer takes that consideration.
    I was originally going to make the cabinets from solid wood but that could have been a disaster
    To put it simply, as someone did for me, wood can be made into an instrument like a note on the marimba. You can't do that with MDF. You can with baltic plywood, it won't sound pretty but it will resonate.
    I'm building a clone vintage Monitor and I'm even now concerned with using MDF rather than the original particleboard. I'm hoping there will be an improvement or at least little difference.

    Post edited by willwilly on
    Will I am
  • DSkipDSkip Posts: 16,288
    The Usher Be-10 I just picked up (trust me, it's not as easy as 'just' picking them up) are made of solid wood, but it's very thick, braced well, and formed with a press.

    I don't think Polk ever used hdf in any designs, but I could be wrong. Hdf is even more inert than mdf. Mdf is a staple in speaker building due to the bang for buck performance it offers.
  • westmassguywestmassguy Posts: 6,457
    Polk used regular particleboard, about as low density as you can get. It has a habit of crumbling.
    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
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
    Cables: Speaker: Furez 10/2 with GLS Locking Banana Plugs
    Interconnect: Furez 10/2 with SpeakONs
    ICs: Custom Furez by Douglas Connections
    Den:
    Bose 901 Series II Continentals Restored, Re-Built Equalizer with Elna Silmic IIs, Sonicaps, and Silver Mica Caps
    Carver CT-3 Pre, Carver C-500

    dhsspeakerservice.com/
    Exclusive Distributor of Gimpod's Custom SDA Circuit Boards

    "And keep her under 70, would you, huh? Betty likes a slow ride"
  • willwillywillwilly Posts: 185
    edited March 2016
    I.e. manufactured wood products,
    Post edited by willwilly on
    Will I am
  • westmassguywestmassguy Posts: 6,457
    Masonite is high density, the stuff Polk used is the exact opposite
    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
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
    Cables: Speaker: Furez 10/2 with GLS Locking Banana Plugs
    Interconnect: Furez 10/2 with SpeakONs
    ICs: Custom Furez by Douglas Connections
    Den:
    Bose 901 Series II Continentals Restored, Re-Built Equalizer with Elna Silmic IIs, Sonicaps, and Silver Mica Caps
    Carver CT-3 Pre, Carver C-500

    dhsspeakerservice.com/
    Exclusive Distributor of Gimpod's Custom SDA Circuit Boards

    "And keep her under 70, would you, huh? Betty likes a slow ride"
  • willwillywillwilly Posts: 185
    edited March 2016
    Keep in mind, partial board is more dense than wood, (more mass per volume) but not rigid, poor strength, and as you stated, degradates especially in water. Partial board is the least dense of the manufactured wood products according to Wikipedia which makes since.
    Post edited by willwilly on
    Will I am
  • willwillywillwilly Posts: 185
    I like the analogy, if you can make an instrument out of it, you probably don't want to make a speaker out of it.
    Will I am
  • DSkipDSkip Posts: 16,288
    edited March 2016
    willwilly wrote: »
    I like the analogy, if you can make an instrument out of it, you probably don't want to make a speaker out of it.

    Unless you can use the resonance to your benefit. Harbeth is but one example of a speaker-builder that incorporates the natural resonances of a cabinet into the design. 99% of designers try to make the cabinet as inert as possible, which is where costs of a speaker begin to really skyrocket. When you look at a high end staple like Wilson or Magico, the majority of what you are paying for is the design/research put into the cabinet design and materials used. They also use great drivers, but those are a small fraction of the cost in most cases. Other companies still try to remove the cabinet completely, like Martin Logan and Magnepan. Magnepan is always considered a great value for high end sound.... if there is no cabinet, you are saving a boatload of cash in the way of not having to build said cabinet.

    There are many different ways to design a speaker and no one way is the correct way, but there are things that have been discovered that have proven there are some wrong ways to build a speaker, such as the M10 design. I think your design looks pretty good (sticking to the original design), but one thing that stands out to me is that you are curving the back of the holes where drivers will be mounted? I think that is a bad idea simply for securing the woofers well enough to the cabinet.
  • willwillywillwilly Posts: 185
    edited March 2016
    Not going to give it up are you. I will concur, the M10 design has its issues, but I like its strengths as crude as some may think.
    This was suggested by another forum. The rational is a driver moves air. Rounding the inside promotes that movement, especially since I'm increasing the thickness of the front panel. I can't see how it would hurt.
    Will I am
  • DSkipDSkip Posts: 16,288
    I like the rounding of the corners, just not the holes for the driver mount. This is a non-issue and can only be detrimental as you are essentially making the mounting area weaker by having less bulk where it needs it most.
  • willwillywillwilly Posts: 185
    Na, slightly weaker. From an engineering point of view, and I am an engineer, the material removed offers little structural support to the mounting of the driver. It can hurt the space between the drivers but drawing that takes more than a few minutes so I didn't show that. I don't plan on routing out the material between the drivers, just hand rounding,.
    So if that is what you meant, good catch.
    Will I am
  • willwillywillwilly Posts: 185
    I'm more concerned about to total lack of cross sectional area horizontally through the drivers but since the front panel is affixed to the casing, maybe a corner block in that area wouldn't hurt.
    Will I am
  • willwillywillwilly Posts: 185
    Non issue, possibly for these drivers in a sealed cabinet system. It was suggested for "ported" (the proper term escapes now) system where the amplitude of the driver or woofer is much greater. (Once I start using the proper terms, I'll start remember them)
    Will I am
  • willwillywillwilly Posts: 185
    Kind of like a three angle grind on a valve if you know what I mean. (Got to throw in an engine reference)
    Will I am
  • willwillywillwilly Posts: 185
    Remember, I'm using 1" MDF, not 3/4" particle board.
    Will I am
  • willwillywillwilly Posts: 185
    rmpolk wrote: »
    If it helps I took some measurements of my 10a's
    Thank you so very much!
    That is great help!

    I plan on plotting it 1 to 1 and confirming with the actual components.

    Thanks again.
    Will I am
  • F1nutF1nut Posts: 43,117
    DSkip wrote: »
    I like the rounding of the corners, just not the holes for the driver mount. This is a non-issue and can only be detrimental as you are essentially making the mounting area weaker by having less bulk where it needs it most.

    Agreed.

    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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