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Beam Blocker vs Foam cutout?

Discussion in 'Amp Central Station' started by scrapyardblue, Jan 27, 2010.

  1. scrapyardblue

    scrapyardblue Friend of Leo's Silver Supporter

    Feb 6, 2007
    central illinois
    Haven't seen any discussion lately about the best way to eliminate the popping or ice pickiness you sometimes get with an amp, more specifically a DRRI. Also seems to be worse with a little delay and compression going.

    Lots of folks like the Weber Beam Blocker as the best solution, but others swear by the Mitchell Doughnut method, a foam cutout between the grill and speaker, leaving the center open. Still others slap a piece of duct tape over the center cone on the grill.

    I'd be happy to hear any thoughts on the subject, especially from someone who's heard both.
     

  2. LaExpatriot

    LaExpatriot Tele-Meister

    455
    Sep 23, 2009
    Central OH
    I am also intereste dto ehar opiions out there. I ahve a DRRI that is painful at times on the highs. Been thinking of the Beam Blocker too but not sure.
     

  3. jwayne

    jwayne Tele-Holic

    597
    Jan 28, 2009
    littleton Colorado
    bump. My AC4TV seems a little ice picky and I was thinking a weber beam blocker but have not researched enough yet to form an opinion of what I think might work.
     

  4. OSdave

    OSdave Tele-Meister

    363
    Mar 13, 2006
    Romeoville, IL
    The "fizzy lifters" on eBay worked really well for me - and they are cheaper and less intrustive than the beam blockers...
     

  5. Will Chen

    Will Chen Tele-Holic

    Age:
    43
    702
    Jan 9, 2009
    Plano, TX
    I'm a fan of the Mitchell Doughnut(Donut?) myself and after reading his explanation a few times actually understand how it works and it is a very different concept than the beam block (which I haven't tried).

    The Mitchell idea is that a speaker radiates sound from every portion of the speaker evenly and by diffusing a large portion of the speaker you get less cancellation of the sound coming out allowing you to use less treble on your amp to achieve the same brightness while throwing the sound around the room much more evenly.

    Weber's concept is to actually reflect back the signal coming directly off the dust cap to increase the comb filtering happening which (presumable) phase cancels some of the high end and throws the sound around the room more evenly due to reflecting the waves in directions the speaker doesn't directly radiate.

    I imagine both work but after employing the Mitchell Doughnut, I have no need to even try out the Beam Blocker as I completely and totally love it.
     
    Salsg likes this.

  6. jwayne

    jwayne Tele-Holic

    597
    Jan 28, 2009
    littleton Colorado

  7. Will Chen

    Will Chen Tele-Holic

    Age:
    43
    702
    Jan 9, 2009
    Plano, TX
    Yep, that's a great explanation but it still went over my head at first. I installed it into my Peavey Bandit and it was a night and day difference. Here's my write up of the experience.
     

  8. jwayne

    jwayne Tele-Holic

    597
    Jan 28, 2009
    littleton Colorado
    I like your article and glad it helped out so much. I ordered the 1/2 and 3/4. I thought maybe 3/4 would be too much for a 10" speaker? With my little vox it has a sweet spot to listen to it...I hope this allows that sweet spot to be in multiple locations and not just one. When you get out of the sweet spot the high frequencies are ice picky...hopefully this does the trick. I'll try to post back what I think...I guess they arrive tomorrow so by Friday I should have an idea on how they worked for me. Thanks will - jw
     

  9. Will Chen

    Will Chen Tele-Holic

    Age:
    43
    702
    Jan 9, 2009
    Plano, TX
    Thanks. I think the 3/4" is what should be used but if I'm not mistaken (think I saw it in this TGP discussion) a 2" inner circle should be cut out for a 10" speaker instead of the 3" recommended for 12" speakers. Good luck and let us know how it works out for you.
     

  10. scrapyardblue

    scrapyardblue Friend of Leo's Silver Supporter

    Feb 6, 2007
    central illinois
    Any types of local stores carry the foam? The Radio Shacks of the world or some other?
     

  11. Ted M

    Ted M Tele-Afflicted

    Mar 27, 2003
    I have a BFDR that I've just installed a beam blocker in. The speaker is an Altec 417 8C, which sounds great, but can be a little bright, especially since I play on the bridge pickup most of the time using a Tele or a 335. I'll be gigging with it this weekend, and I'll post a report. Haven't heard of the doughnut until today.
     

  12. ce24

    ce24 Friend of Leo's

    Jan 26, 2008
    Idahoastan
    on my 5E3 I put a foam front with the hole in the middle and it made it sound mid scooped..at first I liked it but then is started to sound limited..tho no ice pick at all and the sound was the same off axis as well as on axis..interesting

    Cheers
    ce24
     

  13. jwayne

    jwayne Tele-Holic

    597
    Jan 28, 2009
    littleton Colorado
    Teleglide...do you think the beam blocker makes a difference...I know you have not gigged it yet but I have heard people who have installed say that they can notice a little bit of difference but nothing to wright home about. What do you think?
     

  14. Will Chen

    Will Chen Tele-Holic

    Age:
    43
    702
    Jan 9, 2009
    Plano, TX
    You need some type of acoustical foam which is a pretty specialized product. You might be able to find it at some high end stereo store but more than likely you'll have to order it from somewhere.
     

  15. Will Chen

    Will Chen Tele-Holic

    Age:
    43
    702
    Jan 9, 2009
    Plano, TX
    Strange. The foam supposedly is transparent from around 1K and down (same reason why open pore foam products can't sound proof a room). I certainly didn't hear any mid range cut.
     

  16. doublee

    doublee Tele-Meister

    339
    Mar 15, 2007
    The Hudson Valley
    I have used the foam in a DR and 1/2" worked better for me in that it cut down the beam but wasnt as muffled as the 3/4. !0's are less prone to 'beam' to begin with and I didnt like the foam in a 10 (Princeton), too muffled.

    I ended up taking out all foam because I play alone mainly and beam isnt much of an issue, you just need to move your listening spot over a little.

    It does work though for 12's.
     

  17. Shiro

    Shiro Tele-Meister

    394
    Feb 24, 2009
    Sonoma, CA.
    I'm curious about this "simple but effective" Mod. What I'm wondering, is this directional issue specific to certain amps, or will any amp benifit from this mod. It looks like it would be a cheap deal for any manufacturer to install at the time of putting an Amp together. It seems to me the Boutique guys would be all over this, if it improved their sound. I guess what I'm asking is, will this make a good sounding amp sound better?
     

  18. Tele-phone man

    Tele-phone man Tele-Afflicted

    Sep 11, 2006
    Asheville, NC
    You say you actually use LESS treble on the amp after installing the foam? When I read Mitchell's article, I thought he said that if you normally EQ your amp from directly in front, you will likely need to use MORE treble after the foam install to find a similar tone. I was reluctant to try this technique because I usually have my amp facing directly at me, and then EQing accordingly. Since I usually use a Red Box to feed the mains, this would mean a brighter sound than I normally feed the house, which may be a problem since I already advise soundmen to reduce my treble by about 3dB.
     

  19. robt57

    robt57 Telefied Ad Free Member

    Feb 29, 2004
    Portland, OR
    The Mitchell idea

    I have 2 cabs I stuck in a bigger speaker with out enlarging the hole, I will do it later if I keep the speaker in there....


    A 15" in a 12 opeing and a 12" in a 10 opening. I can say I will do the foam in there before I would bother cutting or making a new baffle with the right size hole for the speaker. But more likely I will leave them just as they are, they both sound excellent.

    Jus saying...
     

  20. Joey

    Joey Tele-Holic

    580
    Dec 24, 2009
    New York
    I "road tested" the DRRI's in GC and agree with the "Ice Pic" high similar to what I experienced in my BJ- NOS with the Jensen speaker. I simulated a beam blocker with 4" round piece of cardboard taped over the grill cloth. It tamed the highs a bit, but I was not wild about the overall tone. I ultimately changed the speaker and put in a C-Rex which solved the "ice pick highs as well as improving the overall tone and bottom of the amp.
     

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