dubai2000 Posted February 1, 2015 Share Posted February 1, 2015 I suppose this has been asked before, but despite having searched for a while I am still at a loss.... . Now that the horn bug has bitten again, I would like to try an alternative crossover to the ALKs I am using. My question: can the Type A network be modified to use an 8 ohm mid driver - and if so, what needs to be done? Thanks in advance for any feedback. Wolfram Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 1, 2015 Share Posted February 1, 2015 k Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted February 1, 2015 Author Share Posted February 1, 2015 (edited) So a tap change is all there is to it? It's going to be an Altec 808-8B which seems to be less efficient (104db). Tweeter will be JBL 2404H (105db) Wolfram Edited February 1, 2015 by dubai2000 Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 1, 2015 Share Posted February 1, 2015 h Quote Link to comment Share on other sites More sharing options...
Guest David H Posted February 1, 2015 Share Posted February 1, 2015 (edited) If the Altec is 104 db@ 8 ohms, you may still need to use tap 4 and double the capacitor value. The Atlas is rated at 110db @ 16 Ohm rated impedance. I would try the tap change first. Dave Edited February 1, 2015 by GotHover Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted February 1, 2015 Author Share Posted February 1, 2015 Yep - horn is the 511B. When doubling the cap value, you refer to the 13uF, right? Wolfram Quote Link to comment Share on other sites More sharing options...
Guest David H Posted February 1, 2015 Share Posted February 1, 2015 (edited) Yep - horn is the 511B. When doubling the cap value, you refer to the 13uF, right? Wolfram Exactly. However without an impedance plot it's just a guess. It's probably closer to parallel a 10uF cap with the 13uF considering the K-55 is closer to 12 ohms. I would stick with the ALK, however I understand the need to tinker all too well. Enjoy Edited February 1, 2015 by GotHover Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 1, 2015 Share Posted February 1, 2015 s Quote Link to comment Share on other sites More sharing options...
OO1 Posted February 1, 2015 Share Posted February 1, 2015 The Altec Yep - horn is the 511B. The Altec mid horn/driver you mention is a two way design ie 500-20,000 cps. The A network is all 1st order. A bandpass midrange crossover section would be needed to stop the 511B output from running on into your tweeter. Now you get 1st, 2nd,1st order. The K55V specs 100-4500 cps. So your new horn/driver will be lacking in the 200-500 cps area. another solution is to swap the A crossover and ALK and use an Altec crossover designed for the 808-8B Yep - horn is the 511B. The Altec mid horn/driver you mention is a two way design ie 500-20,000 cps. The A network is all 1st order. A bandpass midrange crossover section would be needed to stop the 511B output from running on into your tweeter. Now you get 1st, 2nd,1st order. The K55V specs 100-4500 cps. So your new horn/driver will be lacking in the 200-500 cps area. how about the crossover N501-8A vs the ALK or A - Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 1, 2015 Share Posted February 1, 2015 f Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted February 1, 2015 Author Share Posted February 1, 2015 My current JBL2470 does indeed drop pretty steeply below 500Hz, but in the current set-up (ALK/511b) it does sound quite good.....and remeber I use a tweeter as well - and want to continue doing so. I understand that Al's network prevents the squawker from playing above the crossover frequency to the tweeter - which the A-Type network does not. Still, I recall some people around here speaking quite highly of older type of nework and thus I am curious. Of course I could use the JBL (16ohm) on the A-Type and use the K400 which doesn't go up as high as the 511, but once the Altec will be here....we'll see . I just wish my head wasn't so slow in understanding the physics behind those networks (and the function of the various parts.... ). Wolfram Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 1, 2015 Share Posted February 1, 2015 d Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted February 1, 2015 Author Share Posted February 1, 2015 (edited) Bass bin is the Khorn..... . Wolfram Edited February 1, 2015 by dubai2000 Quote Link to comment Share on other sites More sharing options...
OO1 Posted February 1, 2015 Share Posted February 1, 2015 ok Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 1, 2015 Share Posted February 1, 2015 g Quote Link to comment Share on other sites More sharing options...
mboxler Posted February 1, 2015 Share Posted February 1, 2015 This is a great read as well...http://www.pispeakers.com/Speaker_Crossover_Lab.pdf Mike Quote Link to comment Share on other sites More sharing options...
djk Posted February 3, 2015 Share Posted February 3, 2015 The 808-8B is 110dB in the frequency range to be used in the Klipschorn. Try it on tap #3 before doing anything else. You may want a small inductor to roll it off above 6Khz or so. Quote Link to comment Share on other sites More sharing options...
Deang Posted February 3, 2015 Share Posted February 3, 2015 The K-55 is also 110. Then we put it on a K-400, and we lose 3dB, taking us down to 107. Then another 3dB down from Tap 4 of the autoformer, and we hit that magical 104dB. The question I have is which horns cause a reduction in gain and which ones don't (I have a hunch). As most know, many of the old networks simply rely on the mass roll off of the driver to create the crossover point. People read the specs for the Atlas K-55 with the single phasing unit, and see that the upper limit is around 4500Hz. This has resulted in people running around making a lot noise about holes in the response and how we have to drop the crossover point to fill in that supposed massive gap between 4500Hz and 6000Hz. How could PK allow something like this to happen?! The truth is that there is no gap. The K-400 collapses the vertical response, and increases the output between 4500 and 6000. In fact, the same happens with any of the aftermarket horns sold by Dave and Greg. Look at any published plot ever put on this forum, and you will clearly see output out to 5800Hz. PK wanted four octaves out of the midrange. He traded off even off-axis energy to get it. Like Dennis said, If you use a midrange driver that runs past 6kHz, you need to add a coil between the output tap for the midrange and the squawker. The size will be determined by the impedance. For example: a 16 ohm driver will need a .40mH coil. An 8 ohm driver will need a .20mH coil. Since you are on the output side of the autoformer, these coil sizes remain the same regardless of what taps you use. It is not the same for the input side, where the capacitor size will change, and be sized based on the impedance at the given crossover point. If the driver is 8 ohm, and your squawker connection is still coming off of Tap 4 - the capacitor will need to go from 13uF to 26uF. The 2470 has a gorgeous midrange, as does the K-55. You are trading some warmth and natural tone for more detail and some vibrancy. It'll be interesting to see where you end up. 1 Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 3, 2015 Share Posted February 3, 2015 ^ I understood that. Quote Link to comment Share on other sites More sharing options...
Axz Hout Posted February 3, 2015 Share Posted February 3, 2015 f Quote Link to comment Share on other sites More sharing options...
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