doityourself Posted January 2, 2007 Share Posted January 2, 2007 I have some homemade khorns with an Audax PR17 6.5inch midrange and EV35 tweeter. I would like some more output from the midrange. Currently running it without any antenuation. I was told by djk that the T2A autoformer could be used to increase the output. How does one hook one up to increase output? Run it backwards? The Audax is rated at 100db efficiency but not in the 400-2k range where's it's slightly less. Where does one buy one and at what cost? Thanks. Maybe it would just be easier to put an L-pad on the woofer section to decrease the bass output in relation to midrange? Quote Link to comment Share on other sites More sharing options...
ZAKO Posted January 2, 2007 Share Posted January 2, 2007 Who wants to hose this one down with the obvious.? Quote Link to comment Share on other sites More sharing options...
doityourself Posted January 2, 2007 Author Share Posted January 2, 2007 Maron (is that your real name or a nickname someone gave you), if you don't have anything constructive to say.... Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 2, 2007 Share Posted January 2, 2007 I have some homemade khorns with an Audax PR17 6.5inch midrange and EV35 tweeter. I would like some more output from the midrange. Currently running it without any antenuation. I was told by djk that the T2A autoformer could be used to increase the output. How does one hook one up to increase output? Run it backwards? The Audax is rated at 100db efficiency but not in the 400-2k range where's it's slightly less. Where does one buy one and at what cost? Thanks. Maybe it would just be easier to put an L-pad on the woofer section to decrease the bass output in relation to midrange? Have you checked the mid-range polairty. In some case, the mid ranges goes out of phase and you loose lower midrange, try reversing the polairty of the midrange drivers and see if you get better midrange. As far as reversing the autoformer question you asked.....Well almost. You might have to also change the capacitor values. But be advised, reversing the autoformer can put some very low impedance loads on your amp. Normally, assuming your 6.5 midrange is an 8 ohm driver, your tap 4=2x=16ohms, your tap 3=4x=32ohms, your tap 2=8x=64ohms. In this example you actually would not have a correct crossover point unless you were on tap3, since the capacitor value was determined using a 16 ohm driver initally. Moving from tap 4, to tap 5, would result on a zero X multiplication factor and an impedance of 8 ohms. This coul doulble your present sound level. However, you would have to change the capacitor based on the new impedance of 8 ohms. Now to take it a step furthur, if you wanted impedance reduction, rather than impedance multiplication, you could wire the autoformer backwards. This has some issues, which I will explain at the end. The new ratios for a backwards wired autoformer would be, tap 4=.5X=4ohms, tap3=.25x=2ohms. Of course you would have to adjust the capacitor values based on the new impedance. Also, keep in mind, if you reverse the autoformer, you increase distortion, reduce dampening factor, but your output will increase. Putting an L-pad on the woofer would require a large L-pad due to the power handling requirements for a woofer. You could use a large autoformer like the atlas af-140 to increase the impedance of the woofer which will have the same net effect of level reduction of the woofer resulting in more midrange presence. If the mid range is an exotic driver, It might be best to have a custom xover mod put together for you after doing an inventroy of your present xover and all your drivers. If the mid range is run of the mil....why not just get some k-55's? Quote Link to comment Share on other sites More sharing options...
TBrennan Posted January 2, 2007 Share Posted January 2, 2007 DIY----Maron is a horny of long and vast experience. I think he's implying you should can the direct-radiator and get a proper horn midrange. Then you'd have no output problem. Quote Link to comment Share on other sites More sharing options...
djk Posted January 3, 2007 Share Posted January 3, 2007 The Audax is only 100dB above 2Khz. To step the level up with a T2: Input cap to terminals 4, 0 Audax to terminals 5, 0 3dB boost, looks like a 4 ohm load to the crossover cap. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted January 3, 2007 Share Posted January 3, 2007 The proper horn K401 is only $50. There are alot of K55 mid drivers showing up at a good price. OR you can double up on the 6" mid speakers to increase output, But in doing that suffer comb filtering. Quote Link to comment Share on other sites More sharing options...
doityourself Posted January 3, 2007 Author Share Posted January 3, 2007 Thanks for the input. I'll try and post some RTA graphs in a couple of days and see what you think. Perhaps the dip from 400-1K is to my liking anyway. The Cornwall certainly has a dip in the midbass. I've heard of putting the PR17's in a smaller encloser to raise the Q to boost the lower range. I'd try some K401's and K55's but one is going to spend over $200 bucks at least and I'm not sure I'd like the midrange horn compared to the PR17. Where can a guy pick up some T2's and at what cost? Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 3, 2007 Share Posted January 3, 2007 "Where can a guy pick up some T2's and at what cost? " BEC on this forum used to sell them. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 3, 2007 Share Posted January 3, 2007 You can reach Bob at bobcrites@centurytel.net Ask for his UT 3636. Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 4, 2007 Share Posted January 4, 2007 If needed you have a second knob to turn. The factory bass horn is attenuated using a notch filter centered near 200Hz (AK-4 network). A discussion about this is in the "Klipschorn Bass Response" thread. More voltage to your mid (djk suggestion) and the notch filter might do the trick. Quote Link to comment Share on other sites More sharing options...
doityourself Posted January 4, 2007 Author Share Posted January 4, 2007 One more thing, in the Speakerlab K plans I used (which had the PR17 in the design) there was a mention of a bass adjustment knob. I didn't have any crossover schematic but from what I can tell it was simply an Lpad on the woofer. Can anyone confirm or deny this? Quote Link to comment Share on other sites More sharing options...
ZAKO Posted January 4, 2007 Share Posted January 4, 2007 Well i guess $200. is too mutch to spend for the mids....So a buck for an L pad to drop overall effeciency is more desirable? Quote Link to comment Share on other sites More sharing options...
Klewless Posted January 4, 2007 Share Posted January 4, 2007 I believe the SpeakerLab crossover had two L-pads. One for the midrange and one for the tweeter. Seems to me that the soulution is a midrange speaker with higher sensitivity. Quote Link to comment Share on other sites More sharing options...
JohnA Posted January 4, 2007 Share Posted January 4, 2007 Maron (is that your real name or a nickname someone gave you), if you don't have anything constructive to say.... This seems like, "Ask a stupid question, ......." Quote Link to comment Share on other sites More sharing options...
ZAKO Posted January 4, 2007 Share Posted January 4, 2007 Klewless & Albright.... Your both right....Constructive suggestions if not done on the cheap are not wanted. A Bose would cost you more. Quality of sound would be the same. Quote Link to comment Share on other sites More sharing options...
doityourself Posted January 4, 2007 Author Share Posted January 4, 2007 I emailed Speakerlab to see if they know anything about the bass adjustment knob. I don't see why one has to spend big bucks for good sound. This thread went from criticism to helpful suggestions back to criticism that is simply not needed. Maron, have you heard the PR17 driver? I didn't think so. Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 4, 2007 Share Posted January 4, 2007 diy-According to the paperwork I have here on the Speakerlab K, the crossover (the "XK") supplied with the kit contained two pads, one for the mid horn and one for the tweeter horn. The mid shown is horn loaded however. jw ps. and don't get too upset with Maron, he's actually a great guy. He just needs to drink the prune juice with the pulp in it next time Quote Link to comment Share on other sites More sharing options...
doityourself Posted January 4, 2007 Author Share Posted January 4, 2007 The Khorn plans I have talk about a bass contour knob. These are the later plans that house the PR17 midrange driver in front of the bass bin. I ran a freq. response of the speaker with the subwoofer running. The bass bin has and Eminence driver with 6.4mn choke. This bass driver is similar to the K33E except is 8ohm with more power handling capability at least according to Eminence. The topend drop is because of using a Radio Shack sound meter turned 90degrees from speaker to make it more accurate in the 8-10khz range. Maybe I don't need more midrange. The meter was positioned about a meter in front of the mid and high freq. box. Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 4, 2007 Share Posted January 4, 2007 diy- the spl meter cannot be used to for measuring amplitude response. A spl meter is simply the wrong tool for the job (also, the RS meter is not even a "marginal" spl meter, it's a toy). If you want to know how to do these measurements Google ClioWin 7. jw Quote Link to comment Share on other sites More sharing options...
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