Re-Coning Allen Speakers

[myorgan]

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Just a quick question about re-coning Allen speakers (in my case, HC-12's).</P>


I just had a fellow do surrounds for a couple HC-12 woofers. When asked if I wanted the single surround or the "accordioned" surround, I chose the single foam surround. In comparing the re-coned speaker (foam) with a replacement new speaker from Allen (accordioned), I've found thefoam surround to yield better results.</P>


Are there any supporting or differing opinions on the matter? Are there any explanations as to why the two types of surroundswould respond so differently to bass frequency response?</P>


Thanks in advance for your input. I have 4 more woofers to re-surround, and wanted to have the Forum weigh in before I took them to be re-done.</P>


Michael</P></DIV>

[Guest]

Re: Re-Coning Allen Speakers



Michael,</p>

My organ is playing through 4 HC-15s, but it came with 4 HC-12s. On the HC-12s, three of the surrounds appear to have been reconditioned with the single foam surround. The fourth one still had its original foam, which was falling apart due to dry rot, so I replaced it with an Allen driver with accordion-style surround. I can't say that I'm overwhelmed the the newer driver in the HC-12, and will probably see about having the old driver reconditioned with a solid surround. </p>

(That said, all of the HC-15s sport the newer surrounds and they sound fantastic...but they're also a whole new generation of design.)</p>

FWIW,</p>

Freddie
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[jbird604]

Re: Re-Coning Allen Speakers



Michael,</P>


The foam allows far greater cone excursion, thus a lowerbass cut-off point. If you recone them all now you'll probably get 15year's use out of them. Yes, the accordion surround will last somewhat longer, but the sound will not be very satisfying on your 505.</P>


The HC-15 speakers, as Freddie mentions, use the accordion surround and they do sound great, though quite different from HC-12's. Allen incorporated a little "bass lift" circuit into their organs when they switched to HC-15's to partially compensate, but the HC-12 still has much more fundamental bass. The HC-15's were in fact never used on channels with 32' stops because Allen knew they couldn't cut it. </P>


All that aside, it is a matter on which there is no unanimity, even among techs. Personally, I'm not crazy about foam surrounds, but I continue to use them in speaker systems that were designed with foam in order to preserve the acoustic balance the designer had in mind.</P>


John</P>
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[myorgan]

Re: Re-Coning Allen Speakers

[quote user="jbird604"] The foam allows far greater cone excursion, thus a lowerbass cut-off point. If you recone them all now you'll probably get 15year's use out of them. Yes, the accordion surround will last somewhat longer, but the sound will not be very satisfying on your 505.


...The HC-15's were in fact never used on channels with 32' stops because Allen knew they couldn't cut it. </P>


All that aside, it is a matter on which there is no unanimity, even among techs. Personally, I'm not crazy about foam surrounds, but I continue to use them in speaker systems that were designed with foam in order to preserve the acoustic balance the designer had in mind.[/quote]</P>


I knew I could find good answers here! Thanks so much. I thought the foam would allow greater movement, therefore greater fundamental frequency response on the 32' stop. What would be helpful is to get a spectrograph of a 32' CCCC playing on both types of speakers to objectively measure the sensitivity/frequency response. Just from listening alone, I'd strongly suspect the foam would win hands-down vs. the accordion-type surround.</P>


On another note (no pun intended), I'm in the process of purchasing an AllenB-20 or B-40 sub-woofer (not sure of the model number). It is 18" and has the accordion surround. I wonder if I should have it changed to foam, or just leave it the way it is. I believe it is the original speaker.</P>


Thanks again for the comments.</P>


Michael</P>

[Guest]

Re: Re-Coning Allen Speakers



Hmmm. I haven't parted with my HC-12s yet. Perhaps I won't. I wonder how my bass would sound on the channel with the 32 stops if hooked up an HC12 and HC15 in parallel and turned the amp WAAAAAY down to balance the other three HC15s. I'll be sure to give a full report!</p>

--Freddie</p>


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