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Re: i think i've found the subwoofer for my jbl 4655's [message #35461 is a reply to message #35459] |
Tue, 12 March 2002 18:19 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Adam
Messages: 419 Registered: May 2009
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Illuminati (1st Degree) |
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Kappa 18A? If you skimp on the box volume, you will be dissapointed in the deep bass response. However, I have two 18A's, 16 cuft ABC boxes. They play really deep and they sound surprisingly nice. They don't have a lot of mechanical power handling, though. I have bottomed them out on normal music with a 100 watt amplifier. But they do get extremely loud in the process! I can't call them my ideal choice for a home sub... But they're good. I'll give you both in their enclosures (covered of course) for $750 :D Adam
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Re: i think i've found the subwoofer for my jbl 4655's [message #35469 is a reply to message #35459] |
Wed, 13 March 2002 08:59 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Colin Fritzke
Messages: 41 Registered: May 2009
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Baron |
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George, Where are you planning on positioning your sub in relation to your JBL's? Are you planning to put it in the corner, or are you going with multiple subs placed under or beside the 4655's? If you must go with Eminence drivers, here's what I'd recommend: Eminence Kappa 15LFA (Adam is very familiar with these). 5.33 cubic feet tuned to 33 Hz will give a nice gradual roll-off with nice extension and relatively deep bass. Remember, this is a high-efficiency driver, so you can't expect sub-20Hz bass out of it. Eminence Delta 12LFA A 3.2 cubic foot box tuned to 38 Hz will give a pretty decent -3dB point of around 37 Hz. With room gain, you could probably expect good bass down into the low 20's range. Get two or more of these woofers and you'll have some excellent SPL. I seem to remember reading Wayne's comments somewhere saying that Pi-Align is NOT really intended for subwoofer design. I feel the same way. Because a true subwoofer is really only intended to cover the bottom octave or two, the rules for successful design are quite different than for a full-range system. Generally speaking, deep bass SPL is easier to obtain from lower efficiency, low-resonance, high-excursion drivers used in multiples and/or with LOTS of power. The LF and LFA drivers in each Eminence range are a good compromise between high-efficiency and low resonance. I think the Delta's and Kappa's are the most user-friendly. Good Luck! Colin
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kappa 15lf vs kappa 18 [message #35472 is a reply to message #35469] |
Wed, 13 March 2002 13:03 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
replay
Messages: 284 Registered: May 2009
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Grand Master |
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thanks again for your help colin. here's my question. looking at the eminence published charts the kappa15lf has a big dip between 30-50hz. the kappa 18's response is smoother with a gradual rise from 30-20hz. also the useable response is 25-500hz for the kappa 18 versus 35-3khz for the kappa 15lf. i'm green at this but to me it looks as if the kappa 18 is the better choice. if i'm missing something help me out please. i'm planning on placing the jbl 4655's on top of the subwoofers and they will be in corners. on top of all this i just received a sample eminence driver(oem) available at a surplus price. take a look at the spec's and see if this is workable as a sub. 18" subwoofer accordian cloth surround 3" kapton voice coil-4 layer 95oz ceramic magnet Re(ohms) 7.84 Fs(hz) 22.74 Le (mh) 1.88 Mms(g) 145.3 Qm 10.30 Cms(mm/N) .3372 Qe .310 Rms(Ns/m) 2.0156 QT .300 Vas (L) 615.56 Xmax(mm) 4.80 Sd (cm^2) 1140.09 BL (Tm) 22.92 EBP 73.40 EFF(%) 2.25 SPL (db) 95.50 let me guess, these 18" drivers need a huge enclosure? thanks for all your help. cheers, george
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Re: kappa 15lf vs kappa 18 [message #35475 is a reply to message #35472] |
Wed, 13 March 2002 15:35 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Adam
Messages: 419 Registered: May 2009
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Illuminati (1st Degree) |
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Replay, I can't honestly say the Kappa 15LF would be good for subwoofer duty. The Q is fine, but the fs of 39 Hz makes it a difficult task. I have run mine in a variety of enclosures, the best being a 5 cuft one tuned to 40 Hz. The f3 was 37 Hz I believe. Good for PA use, but insufficient as a true subwoofer. The Kappa 18A will operate in even a 5 cuft ported box. You could also run it sealed. However, we're talking limited extension. Mine run in 16 cuft boxes tuned to something I do not remember. The f3 is about 25 Hz, though. You can definitely tell. You could probably get similar results in a 12 cuft ported box. I'll run some simulations for you if you want. Adam
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Re: kappa 15lf vs kappa 18 [message #35477 is a reply to message #35472] |
Wed, 13 March 2002 16:10 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Colin Fritzke
Messages: 41 Registered: May 2009
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Baron |
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George, I wouldn't worry about the dip you see in the published response curve of the Kappa 15LF. Eminence does not typically measure their drivers in an appropriate enclosure under real world conditions as I'm sure Wayne can also attest. I can recall reading in more than one article (I can't remember the sources right now) that one shouldn't take the published response graph of ANY woofer very seriously in the range below 200 Hz. The reason being for this is that under the test conditions, more often than not there are response nulls caused by the measuring room and equipment itself. Its nearly impossible to get a truely accurate picture of a woofer's capability for deep bass response from a manufacturer's published response graph. All these graphs are really good for is to show what happens at the TOP of the woofer's useable range where it will generally start to "break up" and distort. You might remember that for a brief time, I was seriously considering using the Kappa 15LFA instead of a Delta 15 for a modified set of Theatre Four Pi's. I changed my mind when I saw that the Delta 15 has some nasty peaks in the frequency response above 1.6K. It really should be crossed over below 1K, which means it wouldn't mate well with the Eminence PSD2002. So yes, I stand by my recommendation for the Kappa 15LFA for subwoofer duty. Colin
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Re: Delta 15 vs Kappa 15LF [message #35479 is a reply to message #35477] |
Wed, 13 March 2002 17:03 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to previous message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18757 Registered: January 2001
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Illuminati (33rd Degree) |
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Hi Colin! I'm sure it was just a "slip of the tongue," but I felt the need to point this out so the Theater four π and Delta 15 owners don't have a panic attack. I think what you meant to say was the follwing: You might remember that for a brief time, I was seriously considering using the Kappa 15LF instead of a Delta 15 for a modified set of Theatre Four Pi's. I changed my mind when I saw that the Kappa 15LF has some nasty peaks in the frequency response above 1.6K. It really should be crossed over below 1K, which means it wouldn't mate well with the Eminence PSD2002. ![](http://www.pispeakers.com/Delta_2015_20graph.jpg) Response curve of Eminence Delta 15
Just thought I'd point that our, for clarity's sake. Wayne
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