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charlieboy

Anyone using Khorns have examples of aligning drivers either physically or with delay etc.....

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Anyone have the tweeter on top at the rear to match the mid driver in alignment? How where the results? I know it all can be done in the digital world with delay but I was just curious what people were doing or what gave the best results. Or if most just enjoy them stock "as is" like I have been lately. I intended to start down the tri-amp direction and DSP about 13 years ago with a set of Khorns I had but sold them and never pursued it after that.. Since then I have recently purchased a pair of Khorns and was wondering if it was worth trying again? They are the tweakers dream and I don't mind starting that process all over again. It's just hard to get motivated lately since I have just been enjoying my Altec 604H II's so much without all the extra tweaking other than tuning the cabinet and really good crossovers.

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1314365747_KhornSEOSrighttopview.thumb.JPG.d2effb3b6477f4782f252ccfdcec14f3.JPGpost-58280-0-56660000-1466716558_thumb.jpgpost-58280-0-71340000-1466716593_thumb.jpgpost-58280-0-75820000-1466733803_thumb.jpg

1 hour ago, charlieboy said:

Anyone have the tweeter on top at the rear to match the mid driver in alignment?

 

Yep, me, with spectacular results.

 

Stock Speaker:  Khorn 1979, Type AA XO.  K-77 tweets, K-55-V mid.

 

New XO:  Crites A/4500 Lowers the XO point of the tweeter from 6000 Hz to 4500 Hz.  The result is that instead of getting squeaks and squawks out of the tweeter now you are getting complete notes and full sounds.

 

External horn:  SEOS 12" Waveguide, by Denovo.  One inch throat.  For comparison my CF-4 horn (2-way) is 12" wide.

 

Compression Driver:  Denovo DNA-360.  The driver has a 1.4" diaphragm.  This mid/tweeter handles 80 watts and goes down to about 1200 Hz.  This combo is gigantic compared to the puny K-77 tweeter.  The output is likewise much more dynamic.

 

Time alignment:  Per previous posts I had read about time alignment I put the SEOS directly above where the throat of the K-55V mid was.  I could not hear any difference between that and OEM in terms of time but there are a lot of variables.

 

Why the new parts:  I just happened to have an extra A/4500 XO ($180 pr used) and the SEOS waveguide ($28 each) w/DNA-360 ($80 ea) from a DIY speaker I had built.  I threw this together not to correct a problem, but just for fun.

 

Look for parts via DIYSoundgroup.  PE used to carry the drivers and SEOS but it looks like they don't any more.  If you do the same mods I did, get the 10" SEOS ($23 ea) instead of the 12".  I think it would make a better HF driver.

 

AVR:  Marantz 6011, 125 wpc tested in Stereo mode.

 

Listening Test:  I like jazz and I test speakers with a horn line, percussion and piano.  also with male and female vocals.  The results stunned me.

 

The Khorns sound fantastic as-is.  The new parts (all installed at the same time) made everything sound better, everywhere in the mid to upper frequencies.  The sound was more articulate, MUCH more dynamic, and MUCH more exciting.

 

I don't have any charts and graphs to back this up, and the WAF forced me to sell them, still my single greatest regret in audio.  The bottom line was these were Khorns on steroids, a Super Khorn.

 

I easily recommend these mods to anyone.

 

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41 minutes ago, charlieboy said:

Anyone have the tweeter on top at the rear to match the mid driver in alignment? How where the results? I know it all can be done in the digital world with delay but I was just curious what people were doing or what gave the best results. Or if most just enjoy them stock "as is" like I have been lately. I started in the tri-amp direction about 13 years ago with a set of Khorns I had but sold them. Since then I have recently purchased a pair of Khorns and was wondering if it was worth trying again? They are the tweakers dream and I don't mind starting that process all over again. It's just hard to get motivated lately since I have just been enjoying my Altec 604H II's so much without all the extra tweaking other than tuning the cabinet and really good crossovers.

 

I made some small baffles to hold some eminence apt50 drivers and horns to replace my LaScala tweeters. I placed them on the back of the cabinets to align them with the k55 mids. Seriously better. While the alignment between the bass and mids would also make a difference, it is more apparent when done with the mid and tweeter.

 

More detail at the crossover point, better imaging, less harsh and fatiguing.

 

Cost is minimal . If you try with new tweeters/horns, you can leave originals in place while you try the new ones.

 

Bruce

post-5045-0-27260000-1398354221.jpg

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I'd opt to do it digitally as soon as I could.  In order to best do it as in the pics you should absorb any and all reflections off the top surface (at least) and especially prevent diffraction off the edges of that surface.  I see that (as shown) as being trading one can of worms for another.

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Yes.... .   I have replaced the top hat of the khorn with an elliptrac midrange horn and a 2404 jbl tweeter.  The tweeter and my midrange drivers are precisely aligned with the tweeter sitting about 6 inches directly above the midrange hardware. I had granite cut to fit the bass bin and the other driver sit on top of the granite.

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Driver time alignment will make a good speaker into a great speaker, worth every penny if you can swing it.

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See the following thread for using a DSP crossover to correct the time alignment and EQ of Khorns:

 

 

Because of the degree of time misalignments in the bass bin--midrange (over 2 wavelengths) and midrange-tweeter (over 8 wavelengths), I don't recommend using analog active crossovers with Khorns, which cannot correct those misalignments.  It is the correction of those time misalignments that I've found is the source of the improvement in sound quality.

 

Chris

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Chief... It should, probably does make a difference. I sit just below the tops of the cabinets, tried different materials, foam, etc., I couldn't tell the difference.

 

I could definitely hear the difference in alingment, though.

 

I'm going to be going digital and adding delays soon. Whole new ballgame since I got some MWMs from JWC.

 

Your new Heresy and Cornwall models look really good, though. Maybe I should sell what I have to get a pair of those.

 

Bruce

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51 minutes ago, Chief bonehead said:

Question. What about the reflection of the horn off the top of the panel?

I can't believe you're asking the question, and I'm answering!  Since I was trained as a therapist, all I'm qualified to do is ask you how you feel about that.  :rolleyes:

+++

 

From what I've read the reflections of the horn off the top of the speaker is not as much of an issue as it would be for a mid horn or woofer.  The reasoning was that the tweeter has a much shorter wavelength and therefore the effect is not as pronounced.

 

Feel free to correct me, it won't hurt my feelings.  B)

 

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6 hours ago, Chief bonehead said:

Question. What about the reflection of the horn off the top of the panel?

 

rps20191024_125118.jpg

 

 

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13 hours ago, Chief bonehead said:

Question. What about the reflection of the horn off the top of the panel?

 

What about it?  😂

 

 


 

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13 hours ago, Chief bonehead said:

Question. What about the reflection of the horn off the top of the panel?

 

I have been mildly concerned about that. 

 

Long time ago (@ 2000?), I thought it was a good idea to front mount my K-77-Ms.  So, I remove the horn of one and reassembled it through the tweeter hole.  Easy.  The second one fell apart in my hands and I broke out in a cold sweat.  Ain't supposed to do that!!!!  Getting the tweeter in front of that hole sweetened the highs (removed a grittiness) and they have been that way ever since. 

 

So, now I have new tweeters that mount from the rear and are flush with the cabinet front, but I'm too chicken to remove the original K-77-Ms.  😁

The new ones are sitting on a pedestal with a cloth table napkin on top of the cabinet.  No way to know if its enough. 

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4 minutes ago, JohnA said:

The new ones are sitting on a pedestal with a cloth table napkin on top of the cabinet.  No way to know if its enough. 

 

How good are your ears? I tried all kinds of materials on the tops when I moved mine and couldn't hear a difference. I not saying there wasn't a difference. But like I said previously, I can't see the tops from my listening position. Sometimes it pays to be short...

 

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A good acoustic absorption material of about 1/4 inch thickness would probably be close to 100% effective at tweeter frequencies (e.g., 4.5 kHz and above).  If thinner than that, you're probably only attenuating incident light and preventing the rattling of the tweeter body on top of the loudspeaker cabinet with a cloth table napkin...:wink:

 

The one inch thickness absorption material that I use is good down to 1 kHz octave band at 97%, and is 70% effective at 500 Hz octave band.  It really doesn't do a lot below 300-400 Hz.  That's where bass traps come into the picture: they're effective down to 70 Hz (the characteristic resonant frequency of the bass trap with one closed end across a room corner).  Below that frequency, it's the movement of the drywall that damps frequencies below 30 Hz.

 

A plot of the measured reverberation time curves in my listening room is shown below (an acoustic measure that is apropos for this discussion) taken at the center position in the room at 1m from the loudspeaker under test.  All the absorption material in-room is within 3-4 feet of the mouths of the horns, i.e., not spread out down the side walls or floor.  There is a thin carpet on the floor in the listening area.

 

Chris A's Listening Room RT60 - 1 Metre Center.jpg

 

Chris

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14 hours ago, Chief bonehead said:

Question. What about the reflection of the horn off the top of the panel?

I was concerned with that too... my configuration was similar to Marvel's.  I placed a couple of layers of felt on the top in front of the tweeter.  I tried thicker egg crate foam but didn't like the result (don't remember why).   

The way I play with audio setup is like playing darts blindfolded... I throw the dart in the general direction and hope for the best.  Sometimes I'm pleasantly surprised and other times it's like I've impaled a cat.  

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Here's a spectrogram of the impulse response of a La Scala II (i.e., ugly):

 

LSII stock uncorrected spectrogram.jpg

 

...and a corresponding spectrogram of a well dialed-in two-way Jubilee (TAD TD-4002 compression driver crossing at ~525 Hz):

 

Spectrogram View Settings.jpg

 

The issues seen in the La Scala II spectrogram are audible--and which look almost the same as a Khorn spectrogram (the Khorn bass bin is delayed about 3ms further than that of the La Scala bass bin).  Even if you move the tweeter back to the plane of the K-55 driver, you still have midrange--bass bin time alignment issues, which are very audible.  The only way to properly align all the channels in these loudspeakers is by tri-amping using a DSP crossover.  When you time align Khorns, their listening performance improves greatly.

 

Chris

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Great information everyone. Can anyone show me Klipschorns or similar photos and the dsp setup you are using?

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Forgot to add text to my post with the photo up the page a bit.  The "phantom" horn image at the top of the photo's what I intended to call attention to.  'Cept in this case it would be below the real driver.  It will seem to be another tweeter in this case, either in phase, out of phase, or some strange combination.

 

And the hard edges along the front and sides in front and below will also variously act as separate sources, too.

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