E network question

[Klipschguy]

Greetings,

 

If one wanted to convert the tweeter leg from a 6db/oct slope to the 18db/oct as found in the AA or the HIE crossovers BUT keep the E network’s T2a tap settings (2 & 3), what capacitor and inductor values would be used?

 

Thank you in advance,

 

Andy

[winglet]

I would think you can just use the same tweeter filter that is used in the HIE or AA if you want the same crossover frequency and slope as those (two 2uF and one .245uH).   It sits between the autoformer and the tweeter and should still only "see" just the k77 impedance.

 

 

 

 

 

[Klipschguy]

Thanks, Winglet.

 

So, the reflected impedance of the T2a tap 3 does not affect the crossover value required in the tweeter leg??

 

I know the tweeter leg of the HIE and the AA bypass the T2a. 
 

 

[winglet]

19 minutes ago, Klipschguy said:

Thanks, Winglet.

 

So, the reflected impedance of the T2a tap 3 does not affect the crossover value required in the tweeter leg??

 

I know the tweeter leg of the HIE and the AA bypass the T2a. 
 

 

There are others here that know WAY more about networks than I do, but that’s the way I understand it since the  tweeter is immediately after the filter.

 

The bandpass (lowpass portion) that is added for ti mid diaphrams for the k53 is similar.  It’s the same componants for all autoformers as it is located just prior to the k53.

Edited January 19 by winglet

[mboxler]

6 hours ago, Klipschguy said:

So, the reflected impedance of the T2a tap 3 does not affect the crossover value required in the tweeter leg??

 

The AA tweeter circuit will change the load, but not significantly.   I think the voltage across the squawker will gradually drop by another 3db or so around 5000hz compared to the stock filter.

 

6 hours ago, Klipschguy said:

I know the tweeter leg of the HIE and the AA bypass the T2a. 

 

Actually, since the tweeter circuit is attached to tap 5, the T2A isn't really bypassed.  In this case, it functions like a 45mh inductor.  Therefore, at very low frequencies, the AA tweeter filter is actually 5th order (30db per octave).  However, because the inductance of the autoformer is so large, it gradually turns into a 3rd order filter at higher frequencies.  Your "Type EE" crossover will behave in a similar way.

 

I always wanted to build  a "Type EE" network.  Go for it!

 

Mike

 

[Klipschguy]

Great info - thanks, Mike!
 

You know, I am always amazed at the level of knowledge on this forum and the willingness to help others; it really is a testimony to the people who listen to Klipsch speakers which in turn pays respect to Mr. Paul Klipsch. BTW, I recently finished rereading his book - a true legend. 

 

Andy

[JohnA]

I did that to my center channel Heresy so it matches my Type AA La Scalas as much as practical.  The Type AA filter EQs the driver a little, but the Type E network compensates for the K-77s response hump well enough and the auto former protects it well enough, too.  You may not notice much difference. 

[Klipschguy]

5 hours ago, JohnA said:

I did that to my center channel Heresy so it matches my Type AA La Scalas as much as practical.  The Type AA filter EQs the driver a little, but the Type E network compensates for the K-77s response hump well enough and the auto former protects it well enough, too.  You may not notice much difference. 

Hi John, 

Did you do anything else to the crossover to match the La Scala?  Just curious. 
Andy

[JohnA]

Yes, I dropped the taps on the T2A, so the response curve is flatter (reduced the rising response by 3 dB).  The result is the woofer at 94 dB/w/m, squawker at 95 dB and the tweeter at 96dB.  My center floats in the air above the TV without much wall reinforcement, so I like the subdued squawker and tweeter better.