Deang Posted July 2, 2016 Author Share Posted July 2, 2016 Right, we're not talking DC or AC power distribution stuff here. I've tried several different methods of doing the common connections, and finally just decided to take advantage of what the wire plate under the screw affords. It digs into the buss wire in a way that a simple screw won't - as good as a good crimp. Quote Link to comment Share on other sites More sharing options...
wvu80 Posted July 2, 2016 Share Posted July 2, 2016 (edited) Basically, the order of the tweeter network is increased. This improves tweeter protection. It is also a constant resistance network, which the typical parallel network is not. Don, what do you mean by the "order" of the tweeter network is increased? Edited July 2, 2016 by wvu80 Quote Link to comment Share on other sites More sharing options...
avguytx Posted July 2, 2016 Share Posted July 2, 2016 (edited) 1st order, 2nd order, 3rd order, etc. Meaning 6db, 12db, 18db/octave slope. It's a steeper slope as the order increases so less information below the crossover point gets thru. Edited July 2, 2016 by avguytx Quote Link to comment Share on other sites More sharing options...
wvu80 Posted July 2, 2016 Share Posted July 2, 2016 I need a little more, AV Guy in Texas. I thought a network would be consistent throughout the entire frequency range. Is the point you and Don are making is that the extra resister will create a steeper slope in the tweeter section only? If so, why is this desirable? Quote Link to comment Share on other sites More sharing options...
avguytx Posted July 2, 2016 Share Posted July 2, 2016 (edited) A single cap in a high pass crossover is a 6db/octave slope. Using a cap and coil makes it a 12db/octave slope. A cap, coil, and another cap is 18db/octave and so on. Gets into what some use with the extreme slopes. Different slopes have different phase shifts. Sometimes in a 12db/octave 3-way crossover, one of the drivers has to be wired out of phase to get it back in phase. A 6db slope is 90 degrees, 12 db is 180 degrees, 18 db is 270 degrees, and 24 db is 360 degrees, or back in phase. That may not help much. A steeper slope allows less information above, or below, the crossover point to get to the driver thus keeping it from playing into an unwanted range. Narrow or steep slopes each have their advantages/disadvantage depending on what the designer is wanting to accomplish with the network and will vary depending on the drivers and application. Edited July 2, 2016 by avguytx 2 Quote Link to comment Share on other sites More sharing options...
Deang Posted July 2, 2016 Author Share Posted July 2, 2016 He's fixated on the two different connection types for the tweeter section. He was curious what Don meant. There is no resistor. Without acoustic plots that show one way compared to the other, it's not easy to explain. The rate increases, but nothing near a full 20dB/decade. Also, the electrical filter response bears little resemblance to the final acoustic response. The electrical combines with the acoustic to create steeper slopes than the electrical alone would suggest. 2 Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 2, 2016 Share Posted July 2, 2016 It's nice to see the stainless screw through that air core inductor. For those of you who aren't going to use stainless on the network, make sure you do use stainless on that. Ferrous metal changes the inductance and therefore the filter properties. The original AA networks used a steel screw to hold that down. I think mine have brass screws. Plus, stainless steel is still predominately steel and will change the inductance. Of course, brass will, too, but very little. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 2, 2016 Author Share Posted July 2, 2016 Uh, no it doesn't. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 2, 2016 Author Share Posted July 2, 2016 All stainless is not created equally- and brass is non-ferrous. What are you smoking? 1 Quote Link to comment Share on other sites More sharing options...
Don Richard Posted July 2, 2016 Share Posted July 2, 2016 (edited) I've seen brass used to tune RF circuits and IF circuits. I seem to remember something like the brass tuning slug decreasing inductance instead of increasing inductance, but anyway a brass screw will have no practical effect with inductors in the millihenry range. 300 series stainless is non-magnetic, may not be the case with other alloys. It's easy to check. Edited July 2, 2016 by Don Richard Quote Link to comment Share on other sites More sharing options...
Schu Posted July 2, 2016 Share Posted July 2, 2016 (edited) ... Edited July 3, 2016 by Schu Quote Link to comment Share on other sites More sharing options...
Deang Posted July 2, 2016 Author Share Posted July 2, 2016 What do you mean Michael? Quote Link to comment Share on other sites More sharing options...
Schu Posted July 3, 2016 Share Posted July 3, 2016 (edited) ... Edited July 3, 2016 by Schu Quote Link to comment Share on other sites More sharing options...
wvu80 Posted July 3, 2016 Share Posted July 3, 2016 Without acoustic plots that show one way compared to the other, it's not easy to explain. The rate increases, but nothing near a full 20dB/decade. I'm somewhat knowledgeable in that I do my homework and read about these things, but I don't always understand. Your explanations as to how XO changes translate into how the sound comes out is the most helpful to me. As usual I think if we sat down together and listened to the same thing at the same time we would probably agree on what the sound is like. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 3, 2016 Author Share Posted July 3, 2016 Maybe. It is interesting that in spite of different hearing curves and subjective preferences - people often agree on what "sounds good. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 3, 2016 Author Share Posted July 3, 2016 Michael, there are only two inductors on the AA. The low pass coil I had UT upgrade for me is a beast. Compared to the stock unit, it's built on a larger frame with heavier gauge wire. The DCR is vanishing low, and my LaScalas absolutely pound. The only downside might be if you plan on pushing 500 wpc through your speakers - at which point the core would saturate. The other coil is in the tweeter filter - and it is an air core. The part is identical to what PWK spec'd out, down to the nasty wax. Quote Link to comment Share on other sites More sharing options...
Schu Posted July 3, 2016 Share Posted July 3, 2016 (edited) :Thumbsup: They look quite Lovely! I love the simplicity despite the giant Capacitors... Edited July 3, 2016 by Schu Quote Link to comment Share on other sites More sharing options...
mustang guy Posted July 3, 2016 Share Posted July 3, 2016 ... Different slopes have different phase shifts. Sometimes in a 12db/octave 3-way crossover, one of the drivers has to be wired out of phase to get it back in phase. A 6db slope is 90 degrees, 12 db is 180 degrees, 18 db is 270 degrees, and 24 db is 360 degrees, or back in phase. That may not help much. ... Thank you, I did not know about the 90 deg phase shift per order of passive crossover. This has me thinking about all of the implications of that. Quote Link to comment Share on other sites More sharing options...
mboxler Posted July 3, 2016 Share Posted July 3, 2016 I may be wrong, but... Each component of the crossover results in a 45 deg phase shift. The inductor to the woofer...-45 deg. The cap to the mid...+45 deg. This results in a +90 deg phase shift between the two drivers. The third order filter to the tweeter is +135 deg (I think) so it is shifted +90 deg from the mid. Please corrent me if I am wrong. Quote Link to comment Share on other sites More sharing options...
djk Posted July 6, 2016 Share Posted July 6, 2016 Posted by djk on December 28, 2000 at 22:56:21 In Reply to: what is driver phasing and how is it affected by crossovers? posted by fullspectrum on December 28, 2000 at 15:44:58: A pole is 6dB/oct and has 90* phase shift.12dB has 180* and when in phase cancels at the crossover point leaving a hole.If you hook one of the drivers out of phase the hole goes away but it doesn't sound right.18dB either leads by 90* or lags by 270* at the crossover point.While flat connected either way it doesn't sound right.24dB has 360* and is flat and sounds right.It is possible to correct for the phase funnies in 12 and 18dB crossovers by using a filler driver.A 12dB with filler is the best I have heard.See the patent for details. https://www.google.ca/patents/US4031321?dq=4,031,321&hl=en&sa=X&ved=0ahUKEwiZw7a6y93NAhULwYMKHU-iDKIQ6AEIGzAA (this is the patent PWK referenced in the LB-76 network patent) Quote Link to comment Share on other sites More sharing options...
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