| Top octave compensation on non Eminence comp drivers [message #36108] |
Fri, 26 April 2002 12:56  |
RyanH
Messages: 20
Registered: May 2009
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Chancellor |
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Very soon I will be building a pair of speakers for PA use with Eminence Kappa 15LFA woofers (already have) and a yet-undecided, but almost definitely the Selenium D205TI compression driver. The D205TI is on sale right now for $35 and I just don't know if I could swing the extra for the PSD2002. Also, for the horn lens I was thinking about going with one of the inexpensive or on sale ones for around $10, would this work? If it is too thin I can coat the back with fiberglass resin or something. I'm basically looking to cut costs the most. Since I will have to build a crossover for this, I was wondering if the top octave compensation used in Pi speakers could be used for this, since I've seen mentioned that its a general compensation for all compression drivers. Thanks for all help in this area, and I will be using Speaker Workshop to model the xovers. I've also got a nasty peak in the 15LFA's response to take care of, so I'll definitely have a challenge ahead of me. Thanks for any help!!
--Ryan
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| yeah [message #36110 is a reply to message #36108] |
Fri, 26 April 2002 14:46  |
dbeardsl
Messages: 127
Registered: May 2009
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Master |
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Yeah. I'm pretty sure you can use it, of course the amount of upper octave compensation is going to depend on how much the main compensation is. Whatever the case, it should work fine. heh though, wait for Waynes answer. Danny. "if it's not you, then do it for the sake of fashion
your friends like a certain you, that's who you've got to be" -Pedro the lion
From "It's Hard to Find a Friend - When they really get to know you they will run"
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| Re: Top octave compensation on non Eminence comp drivers [message #36111 is a reply to message #36108] |
Fri, 26 April 2002 15:00 |
Adam
Messages: 419
Registered: May 2009
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Illuminati (1st Degree) |
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Depending on the horn lense you'll be using, you will likely still need compensation. Bi-radial lenses like the CH-3 will attenuate the top end of the compression driver's response, so compensation wouldn't hurt. However, I don't think you will need as much with that compression driver. Wayne's compensation circuit takes into account the natural rolloff of the PSD2002's as well as flare modification. If I remember correctly, the Selenium compression drivers all go down to 1,000 Hz or so (agian, if I remember right) I would urge you to try taking it that low. If not, a 2nd order LP at 1.5 kHz with impedance compensation will handle the peaking adequately, coming from a guy who has owned a total of eight K15lfa's. Adam
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| Re: yeah [message #36117 is a reply to message #36110] |
Fri, 26 April 2002 21:52 |
RyanH
Messages: 20
Registered: May 2009
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Chancellor |
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Pedro at the Showbox on may 25, I'm there!! Thanks for posting that link, I knew they had a show in Seattle soon, but I wasn't exactly sure when. I think "Its Hard to Find a Friend" is the best CD of theirs I've heard, but I haven't heard all of "Whole" and still need to hear their new stuff. My favorite Pedro song is probably "Bad Diary Days" however, theres just something about it. For Death Cab, I love listening to the entire "We have the facts" CD. Also, check out Ben Gibbard's side project "All time quarterback" if you like Death Cab a lot. I'm excited now for that show, woohoo!
Later,
Ryan
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| Re: Top octave compensation on non Eminence comp drivers [message #36125 is a reply to message #36116] |
Sat, 27 April 2002 08:26 |
Adam
Messages: 419
Registered: May 2009
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Illuminati (1st Degree) |
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No problem. I'm not sure about the power handling issues. The PDF on that unit has the power handling at 1.2 kHz, 12db/octave at 100 watts musical, so maybe 50wrms. That's probably what I would recommend, except 18db/octave crossover instead. With that, you should be fine. I would also recommend impedance compensation on the compression driver. The impedance plot shows two distinct spikes right in the xover point region, which will probably change the function of the crossover. Impedance compensation should flatten these peaks. Adam
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| Re: what did you think about the dip near 6K?(nt) [message #36133 is a reply to message #36130] |
Sat, 27 April 2002 10:45 |
Adam
Messages: 419
Registered: May 2009
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Illuminati (1st Degree) |
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It's a very signifigant dip, around 10 decibels if I read the graph correctly. I'm not sure how to go about fixing this with a passive crossover, but you could at least equalize it out. However, it will be noticable. My other concern is the 15+ decible peak at around 19 kHz. It might be noticable after you use compensation circuitry because it will translate to 15 db above reference. I wouldn't worry about it too much, though. Ryan, after checking out the response graph, it seems to be similar to the PSD2002, except more ragged. You could probably use identical compensation circuits (perhaps use a slightly smaller capacitor value) and still get decent results. Adam
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