Foam 'bungs' - can they make a difference? I think so

Erik Tracy
Erik Tracy Posts: 4,673
edited April 2011 in 2 Channel Audio
So, I've had a **** of a time integrating my sub into my 2-channel setup which uses bookshelves.

Due to room constraints, I have my bookshelf speakers wall mounted with the old BTech mounts. Great for point/angling into the sweet spot, but still - close to the wall, so I get a tad too much bass reinforcement and resulting 'sloppy' bass.

My bookshelves are the B&W CDM 1NTs which are front ported that I picked up used - but the previous owner did not have the original foam 'bungs' (plugs) that fit into the front ports.

I found the USA B&W support center and ordered a set and just recently got them.

They seemingly act as a kind of low cut off device and have allowed me to tighten up the overall bass response with my sub - kinda like an analog equivalent of AVR bass management.

With my integrated amp and directly connected 2-channel sources, I've gotten a slight but noticably better integration of sub & bookshelves, by letting the sub do its job for bass and 'plugging' the bookshelves from trying to reach too deep (and too close to the wall).

Always learning.....

H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
Post edited by Erik Tracy on
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Comments

  • leroyjr1
    leroyjr1 Posts: 8,785
    edited April 2011
    Still got the sealed epik? Are you able to take the speakers off the wall and put them on speakers stands? They'll sound much better.
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited April 2011
    leroyjr1 wrote: »
    Still got the sealed epik? Are you able to take the speakers off the wall and put them on speakers stands? They'll sound much better.

    Still got the Epik Valor - still like it.

    I wish...but there is 'stuff' under the bookshelves since I have a narrow front wall with the HDTV (wall mounted).

    If I had room for stands, I'd probably go towers.

    Life is about constraints, tradeoffs, and compromises....:tongue:

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    Erik Tracy wrote: »
    They seemingly act as a kind of low cut off device..

    ....
    Yes the foam plugs restrict the air flow in the port ,doing so reduces the ports output considerably.Since the ports purpose is to augment the bass below the range that the woofer handles, bass response will be less extended with the plugs.(The speaker will be acting more like a sealed box.)This helps in cases like yours where near wall placement can cause the bass to become too prominate.The resulting higher cut off frequency and shallower roll off slope can sometimes as you found aid in the inegration with a sub.
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited April 2011
    Odd word though...bung.....:tongue:

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • zingo
    zingo Posts: 11,258
    edited April 2011
    I've had the bungs in one of my subs and two of my speakers, and they do work well for restricting and tuning bass.
    Jake
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited April 2011
    bevis.jpg

    huhuhuhuhuhuh....you said bung....huhuhuhuhuhuhuh.....

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • phipiper10
    phipiper10 Posts: 955
    edited April 2011
    Beavis and Butt-head are coming back....seriously dude..

    http://www.comicsalliance.com/2011/02/04/beavis-and-butt-head-return-mtv-this-summer/
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  • madmax
    madmax Posts: 12,434
    edited April 2011
    Covering the ports makes into a sealed box which has a nice 3db per octave rolloff which makes it much easier to mate to a sub. With the port open the response is flat down to some frequency then has no response below that. This is very hard to mate to a sub.
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • Face
    Face Posts: 14,340
    edited April 2011
    A sealed enclosure will have 12/DB roll off per octave and better transient response(depending on Q). Plus blending to a sub will be easier.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited April 2011
    Well - whatever the effects - I'm in a 'happier' spot with speaker-to-sub integration.

    Seems to have tamed a small room peak/reinforcement I was having as well.

    Worth the $ in my book!

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • SCompRacer
    SCompRacer Posts: 8,500
    edited April 2011
    Erik Tracy wrote: »
    Odd word though...bung.....:tongue:

    I've long enjoyed using the term bunghole to describe some folks, in a vulgar slang kind of way.:biggrin:
    Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 *
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  • madmax
    madmax Posts: 12,434
    edited April 2011
    Face wrote: »
    A sealed enclosure will have 12/DB roll off per octave and better transient response(depending on Q). Plus blending to a sub will be easier.

    12db, not 3db. My bad. :wink:
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    madmax wrote: »
    ... the response is flat down to some frequency then has no response below that.
    Well it's not a brickwall.There will still be some output below the ports tuning point but the roll off rate is about twice that of a sealed box at 24db vs 12db.
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  • madmax
    madmax Posts: 12,434
    edited April 2011
    FTGV wrote: »
    Well it's not a brickwall.There will still be some output below the ports tuning point but the roll off rate is about twice that of a sealed box at 24db vs 12db.

    A filter with 24db roll off would pretty much be considered a brick wall filter wouldn't it?
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • Face
    Face Posts: 14,340
    edited April 2011
    madmax wrote: »
    A filter with 24db roll off would pretty much be considered a brick wall filter wouldn't it?

    Not at all.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • madmax
    madmax Posts: 12,434
    edited April 2011
    Hmmm, I do see a writeup considering excess of 50db a brick wall. 24 seems pretty extreme to me for audio.
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D
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  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited April 2011
    I'll admit that I'm a bit slow...so, if other folks are using these - would like to hear about their experiences.

    If others have ported speakers and a sub - you may want to experiment with your own bungs....:biggrin::tongue:

    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
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  • Face
    Face Posts: 14,340
    edited April 2011
    With a typical 24dB(4th order) crossover, there is still plenty over overlap between drivers.

    xovermadfrmodel.jpg

    Joseph Audio's Infinite Slope crossover is the closest you'll find to a brick wall filter in this type of application. You would need to go active to implement this between a woofer and sub, otherwise the parts size and count would be ridiculous.

    josfig03.jpg
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • FTGV
    FTGV Posts: 3,649
    edited April 2011
    That first one is near textbook LR4,I assume it's someones DIY effort?

    Some years back I read the patent for Modafferi's Iinfinite slope .Interesting stuff.
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  • Flash21
    Flash21 Posts: 316
    edited April 2011
    A "bung" is the plug-type thing used to seal up the hole in a wooden barrel...and I didn't even have to look that one up!

    You can always stuff the port with Dacron fill material, as per Mr. Von Schweikert...
    Steve Carlson
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