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


Chris A

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You'd be much better off using those 8-ohm woofers wired in parallel (i.e., 4 ohm load). That's probably the only thing that I'd currently change on the K-402-MEH prototype--to go to 8 ohm woofers wired in parallel.

 

I don't have any reservations about woofers unless the T/S parameters of the woofers are far away from the Crites 1526C or K-33 woofers (any model of K-33).  You're looking for 15" woofers that have a free air resonance around 20-35 Hz and Qts of about 0.3-0.7.  If you're inside those limits, the only other thing is the voice coil impedance. The voice coil impedance 8 ohms is better than 4 ohms or 16 ohms, in order to keep the required voltage levels from the amplifiers down, while making use of their increased current capabilities to 4-ohm loads.

 

The JBL 2226H has a free air resonance of 40 Hz, which is a little high, but it will probably be okay.  The Qts is 0.31, which is on the low side, which is probably good.

 

All DSP crossovers that I've worked with have fast voltage limiters, which will save you from everything but an amplifier failure (short circuit--like you sometimes get with tube-type amplifiers, but not really solid state, which typically fail in open circuit fashion). All you have to do is--do the calculations to set them and then set them from the input screen of the DSP crossover app.

 

If you use dual 18" woofers, they would likely need slightly larger ports drilled in order to keep the same woofer cone area to port area ratio (typically under 10:1).  You'd also have to drill the woofer ports at the right spot in the horn in order to control the crossover frequency.  But 18 inch woofers would have 44% more cone area than the 15 inch woofers, which helps to keep down the modulation distortion and facilitate bottom end extension (if you're loading the horns with proper boundary loading, and not trying to use them out of quarter space or eighth space loading.

 

Chris

 

 

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1 hour ago, Chris A said:

So if you're going to the trouble to produce an MEH, my thinking is that it doesn't make any real sense unless its a full-range MEH that can reach down to frequencies well below 60 Hz.

 

That is what I was thinking, and the reason I asked. 

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1 hour ago, Chris A said:

All DSP crossovers that I've worked with have fast voltage limiters, which will save you from everything but an amplifier failure (short circuit--like you sometimes get with tube-type amplifiers, but not really solid state, which typically fail in open circuit fashion).


In my many decades of electronic service Tube Amplifiers with Audio Output Transformer will rarely send a signal during failure that will damage a loudspeaker and when an output tube shorts it’s more likely to take out cathode components and/or power supply components.

 

Solid State amplifiers Output Transistors can and do short and unless the amplifier has built in DC Protection (many don’t and those that do will often list it as an important feature) on the Audio Output will send almost full Power Supply B+ Rail Voltage to the loudspeaker destroying the voice coil of any drivers directly connected to the amplifier.

 

miketn

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Hi Chris

 

Interesting to see some clear T/S-parameters-recommendations, thank you 🙂.

 

 

10 hours ago, Chris A said:

I don't have any reservations about woofers unless the T/S parameters of the woofers are far away from the Crites 1526C or K-33 woofers (any model of K-33).  You're looking for 15" woofers that have a free air resonance around 20-35 Hz and Qts of about 0.3-0.7.  If you're inside those limits, the only other thing is the voice coil impedance. The voice coil impedance 8 ohms is better than 4 ohms or 16 ohms, in order to keep the required voltage levels from the amplifiers down, while making use of their increased current capabilities to 4-ohm loads.

 

With the AXI2050, it will be possible to move the off-axis ports a bit further away from the throat, making space for for example 4 times  10" or12" woofers in stead of 2 times 15" woofers, so that the woofer can be placed concentric (is that a right word for the dust-cab placed right over the woofer-port?) over the woofer-port. I´ve seen that done by  Mark100 on Diyaudio / gnarly here on Klipsch Community who has placed his woofers in that maner with some god results. I think it gives a more balanced load to the woofer-cone!?

 

Well the question here actually is: Is it always best to wire woofers in parallel or is it OK to wire 4 drivers in series/parallel. Some professional woofers can be had in 16 Ohm, so four of them could make 4 Ohm coupled in parallel.

 

10 hours ago, Chris A said:

You'd be much better off using those 8-ohm woofers wired in parallel (i.e., 4 ohm load). That's probably the only thing that I'd currently change on the K-402-MEH prototype--to go to 8 ohm woofers wired in parallel.

 

Well, work calls!!!!

 

Steffen

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8 hours ago, Supersteff said:

With the AXI2050, it will be possible to move the off-axis ports a bit further away from the throat, making space for for example 4 times  10" or12" woofers in stead of 2 times 15" woofers, so that the woofer can be placed concentric (is that a right word for the dust-cab placed right over the woofer-port?) over the woofer-port. I´ve seen that done by  Mark100 on Diyaudio / gnarly here on Klipsch Community who has placed his woofers in that maner with some god results. I think it gives a more balanced load to the woofer-cone!?

The problem that arises in placing the (off-axis) woofer ports across the middle of the horn walls is that it degrades the most important loudspeaker capability: consistent polar directivity/coverage.  The reason why Danley places these ports in the creases or corners of the rectangular or square horn is that their placement degrades the polar directivity at the frequencies associated with the crossover region (otherwise called "sound power smoothness" in the pie chart below which is condensed down from Sean Olive's linear decision model for loudspeaker preferences--US 8311232)--which is the most important determinant of loudspeaker preference (i.e., more important than flat on-axis SPL).  Placing the woofer port in the middle of a horn wall is absolutely the worst place you can put them, IMHO:

 

Sean Olive Loudspeaker Preference Factors.gif

 

Apparently the guys over on diyAudio don't let little things like that bother them... :wink:  My woofer ports take after Danley's Synergy and Unity horns, both in their placement and their size. 

 

So the area placement and magnitude of the off-axis (woofer) ports is a tradeoff variable.  This is one reason why I set the 10:1 "compression ratio" of woofer cone area to woofer port area, which is high n terms of horn compression ratios.  The reason for keeping this compression ratio under 10:1 is the preserve the efficiency of the low frequency portion of the horn, which is directly affected by the compression ratio used (i.e., inverse relationship between compression ratio and efficiency). 

 

For a study of a four-woofer MEH, look at the SH-96 (using four 15" woofers):

 

450bcd29_vbattach207516.jpeg

 

sh96_specifications_1_031.png

 

I trust Danley's MEH designs.  Everyone else must bring data... :smile:

 

8 hours ago, Supersteff said:

Is it always best to wire woofers in parallel or is it OK to wire 4 drivers in series/parallel. Some professional woofers can be had in 16 Ohm, so four of them could make 4 Ohm coupled in parallel.

It depends on how many woofers and your design requirements.  In general, I think it's best wire the woofers together to achieve about a 4 ohm net load impedance to the driving amplifier(s).

 

Chris

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19 hours ago, mikld said:

I understand they would be possibly overpowered, but i like that get down to 30hz if i decide t use them in outdoor applications (friends concert at the farm).  I would pair them with the appropriate Crown Amp.  on the point above, what would you think about using dual 18" on the long wall of the horn, to create a full range horn that reaches down to the 20s? 

An MEH to 50 Hz. should be your target, then a Tapped Horn sub below that to get you down to the TEENS if you wish.

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On 11/23/2020 at 12:05 PM, Chris A said:

The answer to that is "no".  If you carefully read US8284976, it only patents the current design if you cross over to the lower frequency drivers (woofers, in this case) below the first notch frequency.  If you neglect to cross over, or you cross over at the notch frequency, there is no patent infringement.  I use PEQs to shape the output and effectively use no crossover filters, just trimming filters for overall SPL (and phase) flatness, so the acoustic crossover is at the notch frequency of the lower frequency drivers, and the electrical crossover of the higher frequency drivers is non-existent.

 

The controlling patent (US6411718) expired over 6 years ago due to non-payment of USPTO update fees.  The invention is free and clear, the way I read it.

 

Chris

We DIY types can copy any design we wish without consequence, methinks. Reason being, we are not trying to make a living from it, but just personal enjoyment, like following a Banana Bread Recipe to make our own dessert! IOW, a handful of us freaks making any type of horn we want means nothing to the Corporations in business to make money (redundant statement, I know).

 

However, the nature of my question was in response to Klipsch Engineering and Sales adoption of the methods and creation of MEH's as a new product offering for PROFIT, which would then cut into the sales of Danley Sound labs, since they have a fair amount of market overlap in the PRO Sound world (Theaters, PA, Churches, etc.).

 

So I guess for Klipsch, as a company, to make such a radical departure from their normal product design methods and principles, would be a hard sell, don't you think?

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52 minutes ago, ClaudeJ1 said:

We DIY types can copy any design we wish without consequence, methinks.

That's not what the law says--the last time I looked (and asked a corporate patent attorney the question to confirm).  That's why all "explorations" of others' patented inventions is always shrouded in secrecy--to camouflage apparent infringements by those not holding the patent to build their own (or buying one to reverse engineer it), in order to test and evaluate, then design something different to circumvent the patent. 

 

If you look more closely at US8284976 (the DSL Synergy patent), it actually has three basic invention conditions, the last two of which really can't be enforced because US6411718 (the SPL Unity patent) is prior art that existed in Sound Physics Labs' existing Unity horns almost 14 years earlier.   What changed is the crossover design to avoid trying to push the lower frequency drivers above the first notch frequency, and the resulting phase growth that accompanies that type of crossover design.  That's what the 8284976 patent is all about.

 

52 minutes ago, ClaudeJ1 said:

However, the nature of my question...

What question was that?  I don't see any questions from you just above. I would instead recommend going back to the other thread to flame on the subject you're trying to bring up here--once again--(i.e., the Hyperion thread) instead of cluttering up this one with those type of (non-legal) arguments.  You can have the entire thread to argue such non-legal positions. I've given up trying to have a reasonable conversation on the other thread (the Hyperion thread). 

 

This particular thread was started by myself over 5 years ago to document my prototype K-402-MEH build and its performance.  It's not really a "flame" thread.  It's meant for those that are building their own full-range MEHs for their own use--mostly using K-402s, but also an addendum using plywood construction dual flare horns, and without infringing on US8284976, which is still in effect (fees paid up to date, etc.).

 

Chris

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On 12/4/2020 at 9:13 AM, Chris A said:

You could try asking Tom Danley himself (whom I'm reasonably sure has done some of these trades), but I'm not sure that he would be willing to divulge the generalizations of what his company has found..."the hard way". 

I met Tom Danley, spoken to him one on one. Prior to that, I had some Email communications. He spoke to his business partner about support for his original MEH horns, the SPL TD-1's, for which I had purchased 20 used units from various PA sources. I sold off 16 but still have 4 of them, in the most versatile configuration, which means they can be Tri-Amped, have a Tweeter Level control, all done with the 8 wire Neutrix connectors, which is an industry standard in the Pro Market.

 

In order to identify Exactly what I had, he asked me to do some measurements and send him the files. What he did, free of charge, is to give me settings to use with a Xilica for the purpose of making the olde SEALED versions work more like the modern TH-50's with passive networks (a work of Art, I might add).

 

Tom is a very quiet man, a prolific inventor, whos a DIY guy at heart, is my impression of him. But he is quite busy doing what he does best!

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On 12/22/2020 at 8:49 PM, NBPK402 said:

If you have not ever heard a pair of [mention=62555]Chris[/mention] A MEHs... I seriously suggest you do! I am very impressed with how mine turned out, and there is no way I could buy anything that would sound as good as these are for anywhere near what I have invested. Look for a used pair of k402s, and save some money too. I went the budget route and got EV DH1As, and then a new pair of Emminence kappa 15Cs...DH1As go for about $100 each used. They are not that hard to build either.

 

Sent from my SM-T830 using Tapatalk

 

 

 

 

 

 

I'm glad to see you are still using the drivers I sold you so long ago, which I think are some of the best drivers of their Era, and can be had so inexpensively because they were replaced with NEO magnet versions. The roadies hated the weight of speaker boxes with "mud magnets" but for permanent home installs they are amazing performers, even with a single watt.

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On 11/26/2020 at 12:55 PM, Chris A said:

Yes--on the bass reflex explanation.

 

If you've got two 15" woofers that the K-402-MEH has, you have a bit more "trade off" region than is the case normally with a closed box "acoustic suspension" bass bin (like my K-402-MEH is).  That's one reason why I decided two 15" woofers was the better option. 

 

The Danley SH-96 uses four 15" woofers in its design, which I decided was a more than a little excessive, especially since my loudspeakers are in room boundary coupling below ~50 Hz. 

 

Most people (including some otherwise smart guys in the horn world) typically forget about that boundary loading, and in fact I see many trying to move their loudspeakers away from the room's walls.  It's a much better trade to use the boundary loading and to cover the little area that you need to cover for early midrange reflections due to the closer walls.  That's a much better trade acoustically.

 

Chris

The original SH-96's, were designed, built, and installed in 6 weeks flat for an IMAX Theater in Chicago, along with installing 4 TH-50 subs, butted together to produce a measured output down to 10 Hz. in that install. I used to have 3 in my HT back when my HT room was in a loft inside a Historic Packard Dealership building. With Crown K2's, I'm sure the concrete floors moved a little with the right Blue Ray Movie!! The single one I have now (soon to be 2) scared one of the forum members here more than just a little with the Phoenix plane crash!

 

Even though it was created quickly, it was the pre-cursor to the Jericho line, and certainly a step in the right direction for "big pro sound."

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On 12/31/2020 at 3:07 PM, Edgar said:

Why are you making it personal? I'm thinking like an engineer, and an engineer knows that the Laws of Physics aren't repealed just because you happen to be operating inside a horn. There are near-field effects and there are far-field effects, but since we generally listen in the far field, that would seem to be the place that we should focus our attention.

Isn't home listening ALL Nearfield? With a difficult environment below about 250 hz? Relevance you say?

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On 12/31/2020 at 3:13 PM, Chris A said:

I looked at the SH-50 more closely to understand what Tom was saying (and believe me, I understand a LOT more than I did initially).  I was trying to improve upon the design of the K-402-MEH design so that it could be an improved five-channel MEH surround system in my listening room--that I can't buy, so I have to make them.  I shared what I found in my design with the world, because I'm not making a living off of the design. 

 

Chris

Sure you can buy them from Danley, in smaller and wider dispersion versions than the SH-50. But it's MUCH more educational to be DIY, and much cheaper, money wise (not time wise). Such is the price of education.

 

I do want to say that I appreciate your honesty and integrity when it comes to not revealing all of Tom's "secrets." You get both thumbs up from me on that one!

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On 12/31/2020 at 4:19 PM, Chris A said:

I hope that Tom (and/or Roy, et al.) strays over to this thread from time to time and reads some of the posts here, and that maybe some of them are of interest--which is part of why I posted them. Because I'm basically just a lazy engineer that's retired from his day job--who wants to collect good music recordings and listen to them. 🎶

 

Chris

Ditto

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On 3/29/2021 at 3:07 PM, Chris A said:

The tweeter's horn is integral to the driver, so both the K-77 (or whichever tweeter model is actually used in the Cornwall you own) must be replaced with a tweeter that can extend its crossover frequency down to about 1 to 1.5 kHz.

If this is the only requirement, then I highly recommend the new Eminence N314X driver with the Carbon Fiber Diaphragm (Textreme). I've measured it in a Faital Pro LTH Tractrix horn and it's as smooth as can be down to 750 Hz. From all indications of people who have heard it, it has all the delicate "tinkles" of an unobtanium Beryllium diaphragm without the exorbitant price.

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1 hour ago, Chris A said:

I would instead recommend going back to the other thread to flame on the subject you're trying to bring up here--once again--(i.e., the Hyperion thread) instead of cluttering up this one with those type of (non-legal) arguments.

In keeping within the window of singular post, I assure you that nothing I said was meant to be considered "flaming."

 

Here's what my question was before you perceived a flame: " I guess for Klipsch, as a company, to make such a radical departure from their normal product design methods and principles, would be a hard sell, don't you think?"

 

The reality of LEGAL procedures (I have a family full of Lawyers), it simply would not be worth their time or effort, money wise,  to pursue a Lawsuit with a single DIY guy. This was my main point which you misconstrue as flaming, unfortunately. We are all human, after all. This includes me, you, everyone at Klipsch, Danley, and everyone on this forum.

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2 hours ago, Chris A said:

You can have the entire thread to argue such non-legal positions. I've given up trying to have a reasonable conversation on the other thread (the Hyperion thread). 

OK, you got me curious, so I went back a reread the Hyperion thread. It reminds me of all the posts from people who never heard a Jublilee, passing judgment on it, but even worse, passing judgment on a speaker that doesn't even EXIST.

 

My particular post was a simple reaction to your posting a large image that featured a BULLSHIT button concerning the Hype of a speaker named Hyperion (funny coincidence) that does not yet exist. So yes I thought your picture of a Bullshit button was a bit harsher than required, which sort made your post the "flame," not mine.

My first sentence merely pointed out the FACTS of what you have actually been doing and evolving (MEH) over the last 5 years, in summary fashion. Where's the "flame" you speak of? After all, we all seek better music reproduction wherever we find it, and you have certainly contributed to the science of better understanding in 99% of your posts.

 

If there was any flaming, it most certainly was NOT from me!

 

I stand by all I have posted without need for apology on either side.

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1 hour ago, ClaudeJ1 said:

Isn't home listening ALL Nearfield? With a difficult environment below about 250 hz? Relevance you say?

 

Depends upon the horn(s).

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Hi Chris.

 

5 hours ago, Chris A said:

The problem that arises in placing the (off-axis) woofer ports across the middle of the horn walls is that it degrades the most important loudspeaker capability: consistent polar directivity/coverage.

 

From your answer I can see, that you are familiar with the synergy-builds done by mark100/gnarly over on diyaudio. I do NOT want to place a woofer-port on axis in the middle of the horn wall!

 

My thinking is, that by moving the woofers/off-axis-ports further away from the throat (due to a lover "crossover"-requirement, i.e. 225Hz or something), the off-axis-ports (on the same horn-wall) will move away from each other in vertical distance (if the woofers are mounted on the sides of the horn) when you keep them in the corners!

 

I´m worried to have the off-axis-ports located over the surround of the woofers, as can be seen on several Danley Synergy-speakers. It might not be an issue in PA, but is it an issue in HiFi? Is it a source of distortion, that can be eliminated? Mark100 writes, that he made experiments with the location of the ports relative to the woofers, stating that it sounded best when the ports where located centrally over the dust-cab of the woofer!? 

 

So when the off-axis-ports move apart from each other, say 10-12" , as they move away from the throat (as you have mentioned in your other thread on the AXI2050 in a K402) it could make sense to replace one 15" woofer with two 12" woofers side by side!? 

 

A lot of words!!! I just try to be as precise as possible in stating my point.

 

And again someone might just have to do a somewhat controlled and well planed experiment to sea weather there is an issue or not!?

 

Best regards

 

Steffen

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