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Chris A

A K-402-Based Full-Range Multiple-Entry Horn

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Hi Chris. 

 

"Glad to hear the extra length of my CD s not a problem."

 

Hmm. It might not affect the right placement of the woofer-ports in regard to hornflare (geometry), but how about the upper usable frequency range of the woofers?

I would have thougt that the 1/4 wavelenght cancelation notch frequency is a reflection dependent on the depth of the compressiondriver!? And that that again will affect the upper usable frequency range of the woofer, and introduce the need for an other crossower-frequency/crossower -layout!? Hope I did manege to explain it right?

 

Steffen

 

Steffen

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10 hours ago, Supersteff said:

I would have thougt that the 1/4 wavelenght cancelation notch frequency is a reflection dependent on the depth of the compressiondriver!?

I recommend trying it out yourself: try TAD TD-4002s and then a K-69-A (or similarly shallow throat 2" compression driver) on a K-402-MEH horn.  Also, read the reference that I provided (Huygen's principle).  Ask yourself: at which point does the backward-traveling wave reflect?  Off the phase plug? (No. Before that point--at the first impedance discontinuity it encounters.) 

 

Then we can discuss the point...much more succinctly.

 

Chris

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On 5/22/2020 at 4:02 PM, rickmcinnis said:

Thanks, Chris A.

 

Glad to hear the extra length of my CD s not a problem.  I had remembered your mentioning you had used your TD 4002s and those would probably have an even longer distance with the adapter required to fit the two inches diameter entrance but I would rather know than "find out" the hard way.

 

Yes I knew I would need to chamfer the ports to have as short a wall as possible.  Do you continue the chamfer to the K402's walls - seems like it would be easy to make a very sharp edge with that plastic.

 

Should one chamfer the side facing the cone with a "quick" chamfer or make it as long a smooth transition as possible?  Should one attempt to fill the area between the mounting plate and the cone?  Seems like this could be a good thing but difficult to balance with the ports requiring a small volume.  This is more of an afterthought.

 

Sounds like you are adamant that a good piece of plywood is sufficient for the woofer mounting.  This is welcome news.  That lexan is expensive.

 

I know you had the benefit of using the KLIPSCH box.  I will have to make one.

 

A few questions concerning the box's construction.

 

1.Are you doing anything unusual to seal the mouth of the horn to the box?  I figure some kind of dense foam gasket will be sufficient?

 

2. I assume you are not hearing any noises from the box.  One wonders if the two woofers tend to eliminate some box problems - kind of like djk's PPSL bass cabinets?

     a.  Did you add any bracing to the box?  Are you hearing any need to worry about adding bracing?

     b.  Did you add any damping to the walls of the box like bituminous felt pads or something like that?

     c.  Are you doing anything to connect the walls of the horn to the box?  Do you see any advantage or disadvantage to attempting this?  Would there be any advantage to                  damping the walls of the horn since the ones I am getting is the lightweight version?  Again thinking of those bituminous felt pads the Brits like to use.

 

I will be using two of these in a music system.  I will not be asking them to go below 100 hertz.,  I am hoping this will minimize many potential box problems by  reducing the pressure on the walls of the box. 

 

When I get ready to cut the ports I am going to send you a picture of where I plan on placing them and asking for your approval.

 

I have a few weeks of box making ahead and getting familiar with the horns AS IS.  I have yet to receive them.  Cannot wait to hear how they compare to the INLOWs.

 

Now to find someone who would like to have a pair of the INLOW horns.

 

Got the CRITES woofers.  Compared to the monstrous GREAT PLAINS 515ghps they look like toys.  Sure like the fact that they do not weigh what those 515s weigh!

 

Anyone know anyone who wants a pair of 515ghp woofers?

 

THANKS, again, Chris A.

 

 

 

Would it  be ok to send you a pm, I have a couple questions for you. Thanks.

 

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On 5/13/2020 at 8:42 AM, Jesal said:

Thanks for the spreadsheet. I can live with 26x40". That's not much bigger than what I have now. I will play around with it more.... Thank you Chris

Just remember that the title of this thread is "A K-402-Based Full-Range Multiple Entry Horn", meaning that if you try to skimp on the mouth size of the horn, you also give up directivity of the resulting loudspeaker at midrange frequencies.  I believe that a major reason why the Danley Synergies sound so good is due to point-source controlled directivity in the 200-1000 Hz band.  Most or all folks on other forums fail to recognize this.

 

Chris

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18 hours ago, Chris A said:
Just remember that the title of this thread is "A K-402-Based Full-Range Multiple Entry Horn", meaning that if you try to skimp on the mouth size of the horn, you also give up directivity of the resulting loudspeaker at midrange frequencies.  I believe that a major reason why the Danley Synergies sound so good is due to point-source controlled directivity in the 200-1000 Hz band.  Most or all folks on other forums fail to recognize this.
 
Chris

Understood. I'm a bit challenged horizontally with the screen. I can maintain the K-402 dimensions but will have to turn it sideways. Just trying to decide which is more important and have more advantages, smaller 90 degree horizontal horn or keeping a bigger mouth size but with 60 Horizontal coverage?

Sent from my SM-G955W using Tapatalk
 

Edited by Jesal
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Thanks, AGAIN, Chris A.

 

I have a bass system that works well. I will give it a try in the corners.  I would love to get rid of my modified Seismics - giant monsters using a 18 inches midrange woofer.

 

I have my mouths facing the listening chair and a greatly reduced back chamber and they sound very good in the very limited range I use them in.  Below that are Four RYTHMIC woofers which just cannot get to 50 hz in my room without without excessive downward EQ on the lowest frequencies.  They blend very well with the SEISMICS but there is no question this is a gigantic waste of space for a little over one octave.  I have to say there is no comparison in the sound of a SEISMIC as intended and this bastardized thing I am using.  The bass down to 40 is quick, has good tone and that inimitable characteristic of horns to fill the room without the thumpiness all other systems have.

 

It is as if the SEISMICs get the initial transient going and the RYTHMIKs can then follow - I worry that without these monstrous things the RYTHMIKs would then sound like they are lagging.  I know you will say that I need to use tapped horns and must admit I have always thought of tapped horns as some kind of trick to shake the house!  I havew never heard any and my bias is based on ignorance.  Plus I already have the RYTHMIKs ...

 

I will be using a First Watt J2 for the two CRITES woofers and I am not sure how much bass EQ can be tolerated by the amplifier.  I will be wiring the speakers in series since these amps don't much care for low impedance.  I do not see any effect in HORNRESP either way - the doubled inductance does not make a difference in the sim.

 

I am concerned about the thin walls of the current K402 - I do not see, though they have yet to be delivered - how one can use fasteners at all from your description so instead I am thinking about making the two piece of plywood that will be the woofer baffles about as tall as the side of my cabinet and then using threaded rod to hold them to the walls of the horn and offer some compression damping.  I see these pieces intersecting the top and bottom of the box and affixing them somehow ...

 

I am thinking I should go ahead and do it just like you did - using the sides - I am worried bout messing with something that has been tried by someone who knows what they are doing and has proved this works. Plus the more I thought about it turning the enclosure over occasionally would get old.

 

Still obsessing over how to stiffen/dampen the top and bottom.  Do you think simply cutting plywood to match the shape and gluing it to the horn would do any good?  I would like to something similar as to what I described above but there would not be space!  Should one use a glue that hardens or a glue that remains pliable?  Any thoughts?

 

Can't wait for them to show up so i can get to work.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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32 minutes ago, rickmcinnis said:

I do not see, though they have yet to be delivered - how one can use fasteners at all from your description

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Understood. I'm a bit challenged horizontally with the screen. I can maintain the K-402 dimensions but will have to turn it sideways. Just trying to decide which is more important and have more advantages, smaller 90 degree horizontal horn or keeping a bigger mouth size but with 60 Horizontal coverage?

 

Sent from my SM-G955W using Tapatalk

 

Mine are being setup to where they are vertical due to the floor space they would take up. If you go this way either make your cabinet taller, or make some stands to get them at the proper height. Mine are 4' tall, and pretty close to my ear height for the driver....could go maybe a few more I chest but then I would have to raise my FP.

 

Sent from my SM-T830 using Tapatalk

 

 

 

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20 hours ago, Chris A said:

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1676789273_Boxfront-empty300pix.png.529fbb5403517de425f36f8149f43407.png


Sorry Chris what are you showing with these pictures?  I also was wondering how to deal with fasteners through the thin walls of the horn.  I’m currently leaning towards Ron’s method of gluing stiffening boards to the other 2 surfaces then screwing the woofer mounting boards to those.  This is appealing as a potentially much stiffer surrounding “box” arrangement and doesn’t require fasteners/cutting the horn except of course for the ports.  Thoughts?

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Thanks Chris A.

 

I am am very grateful to you for your inspiration and help.

 

My horns will be thinner and lighter than yours - based upon what you have written.

 

(Mine are (supposed) to be delivered today.)

 

I was meaning, and I realize not as clear as I should have been, about fastening the woofer baffle to the walls of the 402.  I am under the impression that the wall thickness is such that countersinking a machine screw would be impossible to do without a great sacrifice in the integrity of the hole holding the fastener.  I know I will use my tall baffles with the threaded rods to hold the baffles to the horn And the cabinet-  unless reality gets in the way!

 

Certainly attaching the horn to the box at the front should be simple.

 

I am giving very serious thought to getting rid of my Seismic monsters to get the most benefit from the K402 - you are very persuasive.  I like the idea of the 402 MEH being in the corners.  Are you suggesting TIGHT into the corners or just generally?  NOW I see your cabinet is tapered towards the rear.    I am hoping the corner mounting will make EQ for the low frequencies minimal.

 

When you put yours in the corner are they TIGHT into the corners?  If that is the case so much for my rectangular box!

 

So, when you listen to the one MEH with just your tapped horns augmenting them there is not a hole in the response?  Seems from everything I have seen that a tapped horn is a one octave horn, which is fine.  But I wonder about 40 to 80 being filled in properly.  I do not doubt that all is fine with your whole system playing since your JUBILEE cabinets take care of that area with the greatest of ease ...  I know I need to go back and take another look at the measurements.

 

But I am on the trail you have made for us.  Sometimes it takes TIME to see the wisdom of a pioneer.  Thanks for your patience. 

 

Now to hear what K402s sound like tonight if FEDEX brings the boxes!

 

 

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1 hour ago, Delicious2 said:

Sorry Chris what are you showing with these pictures?

How the mouth of the horn is fastened/clamped to the box. 

 

Here is the way that Danley Sound Labs attaches to the interior horn walls--through bolts with countersunk heads...and T-nuts to the long stiffening bolts/rods that attach to the outside box perimeter:

 

31b50c51_vbattach209352.jpeg

 

Chris

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They have arrived.

 

The walls are thicker than I had imagined though i still feel a bit nervous about expecting them to hold a woofer and its baffle without stressing the horn.  I am assuming that Chris A's K402s are made from a thicker material.

 

As far as I know DANLEY is using (at least) 0.5 inch plywood for the horn walls so his using countersunk fasteners is not exactly analogous to the plastic horn.

 

You tap the walls and there is lots of tympanic sound!  Might sound good to MAGNEPLANAR enthusiasts.  No question, unless these resonances are part of Mr. Delgado's intention, they need to be quelled.  Seems like it should be easy to do.

 

 

 

Edited by rickmcinnis

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36 minutes ago, rickmcinnis said:

I am assuming that Chris A's K402s are made from a thicker material.

Yes, they are.  The horns that you have probably weigh 15 pounds.  My K-402-MEH prototype horn weighs 25 pounds.  The K-402s apparently used to be made via compression molding, but were re-sourced from another supplier as an apparent injection molded horn about 3-to-4 years ago, and the overall weight dropped when that occurred.

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what is that countersunk screw holding onto?  Yes, the older horns are heavier/thicker, I have both but wouldn't feel good about countersinking screws in either case - too thin/brittle.

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If one wanted to make a cabinet in the shape of a triangle (would make it a little easier) would it be OK to make the area on either side of a K402 cabinet wider than your cabinet?  It would have to be to clear the back of the horn and the CD.

 

Do you think that width dimension is important?  Would wider mess things up?

 

I can see from your photographs that having something between the K402 enclosure and the floor is needed and obviously not a problem.

 

Sorry for all of the questions.  Ordering baltic birch plywood tomorrow.

 

Thanks, Chris A.

 

 

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2 hours ago, rickmcinnis said:

As far as I know DANLEY is using (at least) 0.5 inch plywood for the horn walls so his using countersunk fasteners is not exactly analogous to the plastic horn.

How so?  The horn material in the third generation horns that you've apparently received recently (and I don't call them "plastic", but rather ABS--because the word "plastic" connotes negatively with most people) is not as tough as the second generation compression molded horns--the ones that weigh 25 pounds, but iin my experience, it's still thick/tough enough to anchor t-nuts and countersunk head bolts-like Danley does in its Synergy series.  I used self-tapping screws in the second generation horn for attaching the woofer mounting pads--made of 3/4" MDF, but I could have also made it with countersunk bolts. The key is expanding the contact area of the head or nut to grab enough material to make the connection.

 

You could also use epoxy to bond to the horn material on the reverse side of the horn (epoxy is really the reference standard for bonding to dissimilar materials), but remember that epoxy is NOT polyester resin--so don't try to use polyester resin to bond to the horn--it probably won't form a strong bond like epoxy will. 

 

Chris

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Well, I apparently listened to the K402 last night.  (My thanks to Kornucopia for bringing my error in typing 401 to my attention)

 

Was taken by surprise by how tight the fit is around the horn mouth for the fasteners of the CD. Had never dealt with studs before.  My previous Edgar salad bowl and the INLOW used bolts that were simple to access.

 

The supplied driver used studs much smaller than the 1/4 inch used by the JBL 2441 - (or the TAD TD4001s and TD-2001s I once had many years ago).  I have ordered some studs but for the moment I was able to use some short screws - could only get two of them in.  Not ideal but I should be able to do it properly Friday afternoon.

 

The supplied stand puts a flange between the CD and the horn.  I was in a hurry to hear something so I left that as is.  When I install the studs i will eliminate that intermediary layer which causes a discontinuity in the throat of the horn.  I will use the flange piece as a support for the compression driver while I am listening to horns pre-.box.

 

Using the top and the bottom for woofer mounting would require some very precise forming of the baffle since there is a curve in the wall.  The sides are flat as can be so that settles that.

 

In case anyone is wondering - these things are incredible - even in a hasty contrived install their vast superiority over the Inlow horns is laughable.  If only I had known of their existence when I bought the Inlows but must admit I had a dim view of KLIPSCH.  I had heard what looked like a perfect KLIPSCHORN installation forty years ago and thought it was the most excruciating thing I had ever heard.  An especially generous room and the speakers set tightly into corners and all I can remember was SCREECH.   It did not turn me off of horns since I have been using my basic Edgar architecture for close to thirty years which had been inspired by a local fellow in the Atlanta area who had made a horn, in the vein of the Klipsch.  His name was John Fusilier.  He had made a set of horns that once I heard those I knew I would have horns one day.  Could not afford them and he was not interested in building another set of them.  He had a little speaker notoriety in the '80's with some conventional speakers he designed and got a good review from The Absolute Sound.

 

I am sorry to digress but this fellow was extraordinary.  I brought over a pair of ROGERS LS3/5a to his house - he wanted to hear them.  He could hear exactly what was being done with the quite complicated crossover.  This was a man with no high frequency hearing in the conventional sense.  He had been a fighter pilot in Korea and was a commercial airline pilot - gas turbine whine had removed most of the high frequencies yet he could still detect with great accuracy.  Remains one of the most extraordinary fellow I have ever met.

 

SO, Mr. Delgado is in my pantheon of audio now.  Chris A. even though you did not think I had really got a pair of these horns, you are in there, also.

 

Back to the K402 - they do lose about 5 db of level compared to the INLOW.  Surprisingly in the low ranges.  They have a major peak in the 3 k area which I left to REW to solve since I did not have time to do it myself.  I like to see what REW suggests but end up doing my own EQ - REW tends to have filters argue with each other.

 

Another surprise is once EQed the high frequencies are far more extended than on the Inlow and they sound GOOD - I am getting plenty of response to 20 khz.  No need for the ribbons at all.  It sounds as if the horn gets out of the way and lets the high frequencies pass through unmolested.  (before the high frequencies sounded like what Greg Monfort properly described them as clever manipulations of surround resonance.  These sound like EXTREMELY clever manipulations that actually sound like overtones.

 

I put on Beatles Revolver since it is one of the few mono recordings I own - and begin to listen to one channel and then the other.  This did not last long.  The K402 was vastly superior - not slightly superior.  I had figured these would be better but my main motivation for getting them was to be able to have an MEH setup.  Even if one does not want to go that route THIS is the horn.  Relaxed yet missing no details - I heard a few things I had never noticed before - even though I do believe as John Broskie says when one is listening intently one WILL hear things they had not heard before and once heard they will always be there.  But the basic timbre and tonality of the horns is so completely different.  It is amazing how different horns can sound.

 

Now to get some plywood and start making boxes.

 

In closing - thanks Chris A for your continued sincere and enthusiastic reports about the good qualities of this horn.  You have not exaggerated in the slightest.  I suspect as I move along I will find you have been circumspect in your praise in fear of being misleading.  I am very grateful for discovering your posts and your work

Edited by rickmcinnis
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On 5/27/2020 at 2:26 PM, Chris A said:

The key is expanding the contact area of the head or nut to grab enough material to make the connection.

 

I use this type of cabinet bolt for attaching the K-402 flange to the mounting brackets. The low profile, wide head design might work good for other applications too.

 

IMG_6879.JPG.a4bb05762697df596e235089ef7fe581.JPG

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23 hours ago, rickmcinnis said:

surprise by how tight the fit is around the horn mouth for the fasteners of the CD. Had never dealt with studs before.

 

In my experience, compression driver mounting studs are common. The K-402 throat does create a tight tolerance, so it is helpful to remove (or install) all four nuts using an even pattern, not just completely removing (or installing) one fastener at a time. After doing it a couple times and learning the technique, it becomes fairly easy.

 

IMG_6894.JPG.e190a011cb1ad4f0bcce8ed4b02600c2.JPG

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