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Peter P.

Foam Padding Inside My Heresy's?

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I bought  my Heresy II's used. I opened them up to examine the insides and found a sheet of foam surrounding the woofer half of the cabinet (just a sheet of foam loosely separating the woofer from the midrange and the tweeter).

 

Since it appeared the previous owner may have tinkered with them, I'm wondering whether the foam was an addition or is it OEM?

 

And while we're on the subject, what's the purpose of the foam found in speakers? Are some materials better than others? Did Heresy's always come with foam?

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Heresys did not always come with foam.  I have seen numerous later Heresies with a sheet of grey foam loose inside the cabinet.  A photo of what you found might help determine whether OEM or the result of tinkering.

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3 hours ago, Peter P. said:

what's the purpose of the foam found in speakers?

 

The original foam insert was installed inside the Heresy II cabinets to help control standing waves inside the cabinet.

 

IMG_4017.JPG.38ce419c472a01ec7b5b2e9775dde3e8.JPG

 

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Khornukopia's picture is exactly what I have.

 

Anybody know if the Heresy III or IV have foam? Same foam and same application? From the way it's installed, it sure doesn't seem like it's too important.

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On 9/8/2020 at 4:15 PM, Peter P. said:

Khornukopia's picture is exactly what I have.

 

Anybody know if the Heresy III or IV have foam? Same foam and same application? From the way it's installed, it sure doesn't seem like it's too important.

 

The foam is exactly where it needs to be, and has not fallen down after 30 years, so it appears to have been installed as good as was required.

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Looks like something OEM would have done. Each Klipsch model I have  had had the same type of foam placed in various configurations.

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I’ve read that foam sheeting is used in speaker cabinets to provide “virtual volume”, so the cabinet seems to be a bit bigger than its actual size, acoustically speaking.

 

And yes, my Heresy IIs have foam sheeting in their cabinets.

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10 minutes ago, Islander said:

I’ve read that foam sheeting is used in speaker cabinets to provide “virtual volume”, so the cabinet seems to be a bit bigger than its actual size, acoustically speaking.

 

And yes, my Heresy IIs have foam sheeting in their cabinets.

 

Hmm, I was under the impression that the foam sheets were used to reduce standing waves in the cabinets. Maybe someone could clarify which way it is used.

 

 

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22 hours ago, Alexander said:

 

Hmm, I was under the impression that the foam sheets were used to reduce standing waves in the cabinets. Maybe someone could clarify which way it is used.

 

 

 

It could be there for both reasons.  Any engineers here who could clarify the reason for foam or Fiberglas sheeting inside speaker cabinets?

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On 9/8/2020 at 9:41 AM, DizRotus said:

Heresys did not always come with foam.  I have seen numerous later Heresies with a sheet of grey foam loose inside the cabinet.  A photo of what you found might help determine whether OEM or the result of tinkering.

right on Neil -

 

-klipsch has been stuffing loose foam for years inside  speakers around woofers  ------watch the AL5 build video at

the 2min 53 seconds mark-  and you'll see a plain gray foam piece inserted around the K33 woofer inside the dog-house

 

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The foam is there to suppress some of the sound energy bouncing around in the enclosure. 

 

As sound waves pass through foam, fiberglass or similar, some of that energy is converted to heat from the friction of passing through the fibers/cells.

 

The amount of foam or enclosure stuffing is always a balance in what you are trying to achieve. Here the amount of foam is relatively small and therefore targets mid range frequencies that could set up standing waves. 

 

Using a large amount of stuffing in a sealed enclosure may act in a way that allows the woofer to "see" a larger enclosure. But this also changes the Q of the speaker considerably so some amount of thought should be given in how you are affecting the enclosure and woofer as a system. Personally, I do not care for the sound of highly-stuffed enclosures. Too much constriction in dynamics. I have tried this on limited occasions so experiences may vary. 

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