| 2 pi tower [message #39225] |
Tue, 26 November 2002 06:36  |
Colin
Messages: 18
Registered: May 2009
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Chancellor |
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Wayne,
Many thanks for the plans. i have located a pair of Alpha 10 drivers, and following Vladimir's advice I hope to find the KSN 1036 at a Monacor dealers, they do not have them in stock but will order them for me.
Now a couple of questions,
What are the advantages and disadvantages from having a front facing port and a rear facing one?
Are there alternatives to the glassfiber insulation? I have lined the loft space of my house with this type of material, not a nice experience, and the idea of all those fine particals being pushed out into the room through the port is not one I like.
Is the only reason that you use such thin board to make use of the sheving material? Would thicker be better?
Please don't take offence at my question's but I am a newbie at speaker buiding.
Colin
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| One answer & one question. [message #39226 is a reply to message #39225] |
Tue, 26 November 2002 07:15  |
mollecon
Messages: 203
Registered: May 2009
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Master |
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Hi Colin! Answer first - to my experience, damping material coming out of the reflex opening isn't a problem in practice. I've used rock/stone-woll for open boxes without any troubles. You can, however, spray the damping material with a hairspray(!) in order to tie lose particles up. Question: Where did you find the Alpha 10's? Thx in advance.
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| Re: 2 pi tower [message #39236 is a reply to message #39225] |
Tue, 26 November 2002 12:04 |
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Wayne Parham
Messages: 18789
Registered: January 2001
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Illuminati (33rd Degree) |
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In most cases, there is no difference between front-facing and rear-facing ports. Bass-reflex speakers are simply Helmholtz resonators with low frequency of resonance. The exception to this is if the speaker is large enough to develop internal standing waves in the passsband. In this case, it is not an issue of whether the port is on back or in front but whether or not the port location is near a standing wave node. This is the case in the two π tower, and for this reason, the locations of the port and the midwoofer are important. About acoustic insulation, there are lots of materials that could work but I always find myself coming back to R11/R13. It works very well. This is also germane to the discussion about standing wave modes. The reason we want insulation spanning the cross-section is it tends to damp the standing wave modes better than just having it on the sides of the cabinet. This is important in the two π tower. As for panel thickness, one school of thought is the thicker the better. I wouldn't object to that but it does get heavy. I would prefer a well braced cabinet to one having thicker panels but no bracing. If a cabinet is small enough, braces become less important but larger cabinets really need them. In the case of the two π tower, the braces 1/3 up from the bottom and 1/3 the way down from the top also serve as attachment points for sheets of insulaton that span the cross-section. So in this case, the braces serve a double purpose.
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| Re: One answer & one question. [message #39238 is a reply to message #39228] |
Tue, 26 November 2002 12:52 |
mollecon
Messages: 203
Registered: May 2009
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Master |
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Hi! No, I'm in Denmark - but maybe an address would come in handy anyway. I could order it from the UK without having to worry about duty/taxes since we're both members of EU. I'm far from sure I can find any Eminence dealers here - maybe Germany could be an option, have to do a bit of searching on that. Btw., what's the price on the Alpha's? I'm sorry, I do not know if the CTS 150 is the same as KSN 1038 - the latter can be found in the Monacor CD-ROM catalogue, & since we have a local dealer here, I think I can get or order it through them. I'll check up upon the CTS 150 thingie the next time I'm looking at the CD-ROM though.
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| Re: One answer & one question. [message #39241 is a reply to message #39238] |
Tue, 26 November 2002 16:51 |
grb
Messages: 5
Registered: May 2009
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Esquire |
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Eminence distributors for Europe may be found here http://editweb.iglou.com/eminence/eminence/pages/support/inquiry/eur.htm I have no association - I was looking for them in Australia. Graeme
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| Thx grb - CTS 150 [message #39252 is a reply to message #39238] |
Wed, 27 November 2002 13:26 |
mollecon
Messages: 203
Registered: May 2009
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Master |
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Thx GRB - I already checked that out. It seems they don't sell Alpha 10's online from the German distributer, so I'm still interested in an address on a British one. & Colin, I checked my Monacor CD-ROM - no such animal as a CTS 150 on that one.
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