| Pi 3 Theater Question [message #47111] |
Tue, 14 June 2005 05:17  |
FredT
Messages: 704
Registered: May 2009
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Illuminati (1st Degree) |
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I'm starting construction of a pair of Pi 3 Theater speakers and was wondering if it would be feasible to convert them to three-ways at a later date by modifying the crossover and adding the midhorn. If I build them with this upgrade in mind I will place the tweeter on top of the woofer enclosure instead of placing it internally. Two questions: 1) Is it feasible to convert the Pi 3 Theater ported enclosure to a three way?, and 2) Is it ok to place the woofer higher in the enclosure instead of at the near-center position in the cabinet plans so it will have the same proximity to the top-mounted tweeter?
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| Re: Pi 3 Theater Question [message #47118 is a reply to message #47111] |
Tue, 14 June 2005 09:24  |
GarMan
Messages: 960
Registered: May 2009
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Illuminati (2nd Degree) |
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Fred, I think that putting the tweeter on top will put it closer to ear-level in a sitting position, and it can be a good thing. Have you consider building the Theater-3 for conversion into a Theater-6 at a later time? I think cabinet volume for the woofer is the same. Gar
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| Upgradability of PI [message #47122 is a reply to message #47121] |
Wed, 15 June 2005 08:36 |
GarMan
Messages: 960
Registered: May 2009
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Illuminati (2nd Degree) |
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Wayne, For me, one of the appeals of your designs is its upgradability, and its too bad there hasn't been much discussions on it. The 3PI to 6PI conversion is a good example. Build a "base" system that performs well as it, but allows you to upgrade for higher performance as needs and funding allows. I had a wonderful experience with the morphing of my original 2PI Towers. Built it on spec at first, then upgraded it to a "Thermionic 2PI". If I had the foresight from the start, I could have built the cabinet to allow conversion to a set of Theater3, which then would have allowed me to upgrade to Theater6. I think this ability for a user to grow with their system can be very appealling. Wayne, any thoughts on putting together an upgrade path for PI systems? gar.
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| Three Pi to Six Pi Upgrade [message #47125 is a reply to message #47121] |
Wed, 15 June 2005 14:34 |
FredT
Messages: 704
Registered: May 2009
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Illuminati (1st Degree) |
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I was thinking of upgrading to a three-way using the bass reflex woofer enclosure because there's a shortage of corners in my house and I can't take advantage of a corner horn. This might require padding the midrange, but I would still get the benefit of the midrange and woofer operating within more appropriate frequency bands. But first things first - I cut out the panels for the woofer enclosures yesterday. The heat index outside is over 100 today, so I'll wait till tomorrow morning to cut the driver and port holes. I plan to install the tweeters in separate boxes that will sit on top of the woofer cabinets. On a different topic, I'm exposing my ignorance here, but I was wondering what's the rationale for using a relatively small port that appears to be tuned to a very low frequency. I would have expected two 3" ports or a single 4" in a br enclosure with a 12" driver. Is this a result of trial and error, or do the Pi enclosures use an alignment other than the standard bass reflex?
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| Re: Three Pi to Six Pi Upgrade [message #47128 is a reply to message #47125] |
Wed, 15 June 2005 17:49 |
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Wayne Parham
Messages: 18835
Registered: January 2001
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Illuminati (33rd Degree) |
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The Theater three π cabinet is a Helmholtz resonator, just like any other bass-reflex cabinet. The alignment is specified by PiAlign, and the values it specifies are not unlike other common alignments.The Delta 12LF is best used in cabinets from 2.0ft3 to 6.0ft3, tuned between 30Hz and 40Hz. EBS cabinets can be a little larger, tuned lower for the bass shelf. But in general, there are a continuum of good alignments in this range. A PiAlign'ed Delta 12LF has a slightly overdamped response, with useable response down to 30Hz. Like the PiAlign'ed Delta 15, this gives bass with gradual rolloff slope and slightly rising response. That makes them perfect for use in corners or as floorstanders against the wall, where room gain might make some speakers tend to sound boomy.
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