Planned to build a pair of Monitor 10 knockoffs, but...

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Starpacer
Starpacer Posts: 2
in Speakers
Over the past year or so, I've slowly purchased Monitor 10 parts, thinking I would try to build my own pair from scratch... I have crossovers, PRs, 6501 drivers, LD0194 tweeters... Then started to notice discussion of comb filtering given the M10 side-by-side woofers, so decided it might be better to build a tower with the woofers on either side of the tweeter, PR at the base. Knowing nothing about tuning a PR, my original plan was to copy the M10 dimensions exactly, but if switching to a tower design, I'm wondering about the interior layout of the M10s - are there any baffles inside? and would baffles help the upper-lower woofers in a tower couple to the PR ?

I do realize that I could just buy a pair of RTA-11t's LOL.
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  • Gardenstater
    Gardenstater Posts: 4,944
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    Baffle? The M10 does have a brace to stiffen the baffle but it doesn't have anything to do with coupling to the PR which is entirely acoustic. Check out this thread where joebass3 did westmassguy's mod to his M10s and got great results. It mitigates the combing and filtering and improved the imaging and freq. response. You can see the original brace from Polk which is colored black and joe's additions are in particle board:

    https://forum.polkaudio.com/discussion/173834/westmassguys-idea-employing-damping-to-mitigate-comb-filtering-and-lobing/p2


    qgkkyb1ec423.png
    George / NJ

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  • Starpacer
    Starpacer Posts: 2
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    Thanks - just what I was looking for! 'Baffle' might not be the correct terminology - picturing interior structure that would potentially direct sound as it bounces around back there..
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  • Gardenstater
    Gardenstater Posts: 4,944
    edited October 9
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    The resonant frequency of the PR is 60 Hz and at that frequency the wavelength is 18 ft, 8 in.. So think more about sPL than "bouncing". Any materials inside the cabinet that would tend to absorb sound at that frequency might dampen the very low frequency response. You would need a lot of fairly thick stuff like that BH5 that joe and westmassguy and Jazzhead used to have much of any effect at that frequency.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • Ryan_Polk
    Ryan_Polk Posts: 71
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    Hey @Starpacer, this sounds like a cool project. I'd love to see some pictures if you are able to take some and share with us. Gardenstater is right on the point, you'd be looking at internal bracing and dampening material.

    I am currently working on a project using DT drivers that I am experimenting with recycled denim batt to help tame the lower freqs just to see what happens. I had a CS9080 sitting around that I gutted for the drivers and decided to work on 3D modeling an enclosure that I will start printing in PTEG and encasing in resin once I move into my new home later this year. I'll try to get pics at some point when I finally can get started on this project.
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