SDA 2B placement

2

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  • rhythm
    rhythm Posts: 52
    F1nut wrote: »
    ... Nice neat job on the crossovers.

    Courtesy of westmassguy!
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  • rhythm
    rhythm Posts: 52
    Well if the gaskets behind the drivers and binding post cups look good, I guess the next most likely place (for air leaks) would be the joints around the inside of the cabinet?

    Pretty sure I'm hearing an air hiss in the area of the MW's, but if it's from the dust caps I guess there's not much I can do there.


    Greg
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  • Gardenstater
    Gardenstater Posts: 4,459
    What' the deal with this spot? Kind of hard to tell from the photo but something definitely isn't 100% normal. It might not be leaking though. Yes it is probably a very good idea to run a healthy fillet of some adhesive of your choice around all inside cabinet joints. There is usually lots of excessive adhesive that may have cracked loose and may not be bonded to the particle board any more. I haven't done my entire cabinets yet. I'm indecisive on whether to cut away the excess or not. I probably will and then will probably run a healthy fillet of JB-Weld all around with a tongue depressor.

    b5gevmjectmo.jpg
    George / NJ

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  • motorhead43026
    motorhead43026 Posts: 3,897
    edited October 2021
    ^^ that is not the original gasket material, looks suspect.
    The best way to predict the future is to invent it.

    It is imperative that we recognize that an opinion is not a fact.
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  • michaeljhsda2
    michaeljhsda2 Posts: 2,182
    The gasket material definitely looks original IMO.
    SDA SRS 2.3TL's
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  • motorhead43026
    motorhead43026 Posts: 3,897
    Here is original and note the position.


    bfl2o6vba29q.jpeg



    The best way to predict the future is to invent it.

    It is imperative that we recognize that an opinion is not a fact.
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  • F1nut
    F1nut Posts: 50,539
    that is not the original gasket material, looks suspect.
    The gasket in question is original.
    Here is original and note the position.
    You're comparing a driver to the binding post plate.
    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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  • motorhead43026
    motorhead43026 Posts: 3,897
    edited October 2021
    ^^^ I see said the blind man, my mistake.
    The best way to predict the future is to invent it.

    It is imperative that we recognize that an opinion is not a fact.
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  • rhythm
    rhythm Posts: 52
    Well, I was kind of hoping I wouldn't need to seal up all of the joints inside the cabinet, but since the gaskets all seem to be in good shape I probably should do just that. I attached a picture of the inside and I'm wondering whether or not I need to scrape off all of the 'goop' that's already there, or if I can just apply something right over it. You can see they really slathered a lot on there in places.

    And by the way, what's the preferred sealant for doing this?


    Thank you,
    Greg
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  • F1nut
    F1nut Posts: 50,539
    edited October 2021
    With that much glue in there I seriously doubt there are any air leaks.

    Are you pushing and holding the PR in or are you releasing it immediately?
    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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  • rhythm
    rhythm Posts: 52
    I am pushing and holding it in. This weekend I'll try to make a short video of the MW drivers as I do this. Perhaps I'm counting too slowly or something. This way others here can see what I'm seeing and let me know what they think.

    I'll double-check the PR gaskets this weekend also. I thought I remember them looking just fine when I removed the crossovers for the overhaul, but double-checking can't hurt. It's been a while.

    Thanks,
    Greg
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  • boston1450
    boston1450 Posts: 7,636
    Are you testing this by yourself ? If your hearing a leak & you can hear it, you should be able to find this leak with help from extra hands. I see the crossover bolt to mount crossover to cabinet - check that area also. I used LocTite Powergrab on inside of my cabinets just to be positive with great success. You'll find er
    ..
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  • joebass3
    joebass3 Posts: 284
    Since you're in there already, no reason to not seal the inside of the cabinet. Peace of mind.
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  • rhythm
    rhythm Posts: 52
    Am I allowed to attach a short video? Doesn't seem to be working.

    Thanks,
    Greg
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  • VSAT88
    VSAT88 Posts: 1,257
    Do you hear the hissing sound on just one speaker or both ? If its both you are probably good to go. If just one then there is a snake behind the speaker. OR you do have an air leak in that one. :D
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  • rhythm
    rhythm Posts: 52
    I hear the air on both speakers. I'm nearly certain it's coming from the dust cap area. The gaskets everywhere seem fine and it looks like there's plenty of glue all around the joints inside so I'm not sure where they'd be leaking. I made a short video of the MW drivers while doing the leak test, but I haven't been able to attach it to a post. I'll keep working on that.

    Thank you,
    Greg
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  • Gardenstater
    Gardenstater Posts: 4,459
    edited November 2021
    A few things come to my mind. First, you must have superhuman hearing :) 2nd you may have a cracked spider and/or dust cap, but to have it on both speakers seems unlikely. More likely to be a cracked spider. The spiders are definitely somewhat porous anyway as are the dust caps but it could just allow more air to escape faster.

    Do you have any other MW drivers you could swap in for leakdown testing?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
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    Logitech Squeezebox Touch Streamer w/EDO applet
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    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • rhythm
    rhythm Posts: 52
    edited November 2021
    I definitely don't have superhuman hearing :) So maybe I'm not hearing air like I think I am. I definitely hear some kind of hiss where the MW's are, but maybe it's just the sound of the drivers pushing outward? Unfortunately I don't have any other drivers around to swap out.

    Here is a link to a quick video I made. Hopefully this is useful. Just wondering if any of you also feel that there's a leak based on the time to recede. The 'clanking' noise as the drivers are pushed out is not the speakers, it's other background noise.

    Thanks,
    Greg

    https://youtu.be/-jyOZFRSrFk
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  • F1nut
    F1nut Posts: 50,539
    The drivers are receding too quickly. It should take 3 to 5 seconds, yours take about 1.
    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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  • Gardenstater
    Gardenstater Posts: 4,459
    edited November 2021
    About the excess glue squeeze out, it could still be brittle and cracked in places. I say this because I had my 7B's on the *operating table* many times and the last time I worked on them to put the Rob's Rings in, I leaned a bit too much on the baffle down by the passive hole and heard a definite crack sound (Doofus!). Sure enough there were now cracks in the excess squeeze out visible. I think the adhesive gets very brittle over time. That's when I pulled out the JB Weld and did an emergency repair where I put the stuff right on over the excess and did a fillet all around the lower part of the baffle until I ran out of epoxy. I'll have to do it right some time.

    I think you need to seal your cabinet joints as previously suggested.

    I watched your vid and my 7B's definitely do not do what yours do, where they initially move back in part way too fast and then seem to hold that position or move very slowly from there until you release the passive at which point the fully retract. Mine are slow and even retraction.
    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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  • rhythm
    rhythm Posts: 52
    Thank you very much for the feedback! I'll go ahead and seal up the cabinet joints. I figured I was failing the leak test but I appreciate the confirmation after viewing the video.

    I've seen various things suggested for sealing the inside joints: Loctite Power Grab, JB Weld Epoxy, wood glue, etc.


    Greg
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  • F1nut
    F1nut Posts: 50,539
    You want a silicone free caulk type product. Wood glue and epoxy are not good choices.
    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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  • TennMan
    TennMan Posts: 1,266
    What is the clicking noise when you push the passive in and release it? My 2Bs don't make that noise.
    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
    • Crossover upgrades by westmassguy
    • Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    • Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
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  • boston1450
    boston1450 Posts: 7,636
    ^^^^^ vqmfhe7r15lc.png
    ..
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  • boston1450
    boston1450 Posts: 7,636
    I thought the same. Like a bracket inside the cabinet.... I had a loose something on my 2b's years back. Getting old sucks. CRS
    ..
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  • michaeljhsda2
    michaeljhsda2 Posts: 2,182
    That noise in the background sounds like someone's doing the dishes.
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  • TennMan
    TennMan Posts: 1,266
    It sure is odd the the clicking sound coincides perfectly with the passive going in and out.
    • SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat
    • Crossover upgrades by westmassguy
    • Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
    • Adcom GFA-555 amp · Upgrades & speaker protection added by OldmanSRS
    • Pioneer DV-610AV DVD/CD player
    • SDA CRS+ · Hidden away in the closet
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  • rhythm
    rhythm Posts: 52
    edited November 2021
    I know, that's why I made the comment about the noise not being the speakers - because the timing is so suspect. I didn't even realize there was something going on in the background until I uploaded the video to YouTube. :)
    I will probably pick up some of this for the inner joints.
    https://www.homedepot.com/p/Loctite-Power-Grab-Express-6-fl-oz-All-Purpose-Construction-Adhesive-Squeeze-Tube-2029846/206432100

    And I guess while I'm in there I could make some other easy improvements also, such as Dynamat on the baskets and BH5/Sonic Barrier behind the woofers.


    Greg

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  • Gardenstater
    Gardenstater Posts: 4,459
    Check the spiders for cracks while you are at it. It may only open up and be visible when the cone is displaced close to the extreme travel limits.
    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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  • muncybob
    muncybob Posts: 3,042
    F1nut wrote: »
    You want a silicone free caulk type product. Wood glue and epoxy are not good choices.

    Why? Will it damage the cabinet over time?
    Yep, my name really is Bob.
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