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Chris A

Multiple Entry Horns [MEHs]--the "Why" and their Future

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I think it's instructive to understand what a multiple entry horn (MEH) is and why it works so well.  I'll take some excerpts (with revisions) from a white paper on the subject:

_________________________________________________________________________________________

Horns are beneficial in radiation of acoustic energy across the audible band of frequencies. To make horns useful for loudspeaker design, it's important to:

 

1) provide good loading for the loudspeaker drivers [for higher efficiency], and

2) provide uniform directivity control across as wide a frequency span (bandwidth) as possible

 

Reproducing the frequency spectrum typically requires multiple drivers of varying sizes.  Using traditional design methods, this puts the loudspeaker drivers and/or horn mouths at different physical locations. Using that approach, It's difficult to maintain a uniform radiation pattern throughout the crossover region from one device to the next. For directivity control at low frequencies, size is required.  For instance, to achieve full 50° pattern control from a horn at 500 Hz, a mouth size of approximately 40 inches is required...

 

So there is a size advantage to be able to use one large horn instead of multiple horns. Using one large horn while maintaining reasonable enclosure size is the goal.  Coaxial horn arrangements have been used in the past, i.e., nesting smaller high frequency horns inside a larger mid frequency horn (or driver cone).  Another design is to have the drivers for each frequency region all drive the same horn.  Both of these methods have the advantage of using the entire front area of the loudspeaker enclosure as the horn mouth.  Multiple entry horns [MEHs] couple the radiation from multiple drivers into a single horn to approximate the performance of a single horn/driver system with high efficiency and excellent directivity control.

 

A straight-sided horn can yield very consistent directivity control over a wide frequency range.  The problem with using a straight-sided horn is that it does not provide good low frequency loading to its driver (if the low frequency driver is located at the throat of the horn).  The loading a horn presents to a driver can also be viewed as the expansion rate of the horn.  A 125 Hz exponential horn has an expansion rate that doubles its cross sectional area every 6 inches of horn length while a 500 Hz exponential expansion doubles its area every 1.5 inches...

 

A straight-sided horn expansion has an expansion rate that is very rapid close to its apex (throat)--it doubles its area in a very short distance, but as the distance from the throat is increased toward the mouth, its expansion rate decreases.  For every point along the axis of the straight-sided  horn, there is a different expansion rate and in turn a different low frequency cut-off.

 

                                                Straight-sided Horn Low Frequency Cut-Off

1848906890_striaght-sidedhornoff-axisportloadingcurve.JPG.a3643ce4535c6feced9987b2b281e49c.JPG

 

By using this effect, a straight-sided horn can be driven at the appropriate place along its length to yield good low frequency loading on the woofers.  This is one of the principles governing the driver placement within the MEH: lower frequency drivers are placed closer to mouth where the horn provides better loading within the frequency region (pass band) where these drivers are used.

 

There are several other similar principles that dictate the driver placement for each pass band within the MEH.  When these constraints are observed, the result is that multiple drivers  operating in multiple frequency ranges are very effectively coupled into a single horn.

________________________________________________________________________

 

MEHs are new compared to traditional multiple-horn horn loudspeakers, and they have real advantages over them and few if any disadvantages. From another thread on this subject, here are some advantages over traditional horn loudspeaker designs:

 

  1. They increase measured and subjective clarity over other conventional fully horn-loaded loudspeakers due to their point source capability & undisturbed constant directivity (i.e., no lobing). 
  2. Properly set up, and without requiring FIR filtering, they have almost linear phase behavior as compared to other full-range horn loaded and direct radiating multiway designs.
  3. They can have useful directivity from 110 Hz-17+ kHz (depending on HF driver)--the same as the Khorn and Jubilee, and more effectively take advantage of room corners to further directivity and boundary gain below 110 Hz due to their large mouth size, the absence of bends in the horn path, and small form factor.
  4. They don't require a corner to have -3 dB roll off response down to 32 Hz (albeit without the advantage of its own directivity gain below ~70-90 Hz).
  5. A full-range MEH loudspeaker can have a 1/3 size form factor as compared to a Jubilee.
  6. They can have high efficiency of horn-loading.
  7. They typically have significantly lower costs of production over a typical corner horn loudspeaker.

 

That's a significant set of advantages over a corner horn or other fully horn-loaded loudspeaker, and is something that even the "full range" driver aficionados (e.g., Fostex, etc.) are looking for, but can't really achieve.

 

The downside of MEHs?  No downsides are implicit in their design, but there are some design considerations that must be realized:

 

  1. Their bass performance, like the corner horn, must either make use of the room's boundaries (i.e., quarter space along a wall/floor interface or eighth space corner loading) must be used to supplement their bass extension, or their bass response must follow the same efficiencies as slot-loaded bass bins, i.e., like bass reflex, etc., and this can mean higher modulation distortion and lower bass efficiencies below the horn loading frequencies.
  2. Their crossover designs can be quite challenging.  By this, I mean that if you are thinking about using a passive crossover in a three-way MEH design, be prepared to spend significantly more time tweaking the crossover filters than in a standard direct radiating or multiple-horn loudspeaker.  Fortunately, the advent of very high quality and economical DSP crossovers and bi-/tri-amping makes this trivial.
  3. Their mouth form factors are generally square to golden rectangle (1.618:1) ratios.  This means that they are not "slim and tall", but rather rectangular or square, and they have about 15-25 inches of depth.  If you want full-range operation of the MEH itself, the horizontal and vertical dimensions of the horn mouth will be ~35x21 inches.  If you're willing to give up directivity of the bass below ~500 Hz and use a direct radiating bass bin under or over the MEH itself to complete it's frequency response capability, the mouth size of the MEH can be as small as 13.5 x 7 inches but the real advantage of MEHs is lost when you do this, IMO. 

 

Chris

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The future of MEHs?

 

Currently, there are legal issues that surround their design and production, but in general, the originating patent (US6411718) has expired, "prior art" is the controlling legal principle, and any other later patents will not be able to legally constrain free use of the design. 

 

Other than that, the remaining issues that have limited its more widespread acceptance seem to be:

  1. Few people have seen and/or heard well designed and well set-up MEHs as compared to good horn loaded or direct radiator loudspeakers.  (This problem is not unique to MEHs, but rather all high quality hi-fi loudspeakers nowadays.)
  2. MEHs with a wide horizontal coverage of 90 degrees or greater for home hi-fi use seems to be even rarer. 
  3. The price of existing MEHs has been high to date.
  4. The design of existing MEHs has not been optimized for home hi-fi use, i.e., they have been designed for very high output PA use.  As such, they also have not generally been finished for home use (such as having veneer like the following 50-degree horizontal coverage models):
     
  5. 2064834243_SH-50veneered.thumb.jpg.7d1f62d26ff6bfb6619d2b6026db055a.jpg
     
  6. There seems to be widespread unfamiliarity with the subjective listening advantages of MEHs, i.e., full-range controlled directivity, very wide listening area that is not constrained to a "sweet spot", very low modulation distortion, very low group delay and phase growth.  I believe that this has particularly led to the realization that many audiophiles may have "accommodated" to the sound of direct radiator loudspeakers rather than the sound of live music.  (This is not unique to MEHs, however, as many "audiophiles" also have given the same undeserved bad rep to Klipsch horn-loaded loudspeakers.)
  7. They don't look like other high quality hi-fi loudspeakers--nor are they as large, heavy, and costly as most of those "high end" designs.

 

In short, there currently are some significant obstacles to be overcome, and the current spate of MEHs has not really addressed the home hi-fi demand.  So the future of MEHs is the real focus of this article: how each of the impediments listed above can (and likely will) be overcome, and how MEHs will likely affect the future of high quality home hi-fi loudspeakers, which is a subject of interest to many that frequent this forum.

 

Chris

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If we consider a new product model derived from from Clayton Christensen's work, there are typically only four areas that affect how well a new product is likely to do in the marketplace:

 

1845312079_ChristensenProductHiringModel.jpg.fb1077143b0c600c3275208f9adb5729.jpg

 

In this chart, the four axes of concern are: "lower price", "greater benefits" (i.e., the product performs to the user's needs better), "easy to use", and "easy to buy".  Right now, the greater benefits portion of the puzzle is the focus of much that was written above.  We haven't talked much about "easy to use", "lower price", and "easy to buy".  I hope that the discussions that follow use these areas of concern to focus their discussion, since these have proven to be the main sources of product acceptance and market success.

 

"Easy to Use"--  The MEHs that I own and have used have been exceptionally easy to use over other horn-loaded  and direct radiator loudspeakers, especially when talking about untreated listening rooms.  The concern in this area is that these are not "small loudspeakers" but rather "high performance".  Additionally, after the crossover parameters are dialed in for the MEH along a wall or in a corner using a DSP crossover, switching their bass bin equalization curves to match the room loading (corner, along a floor-wall junction, or mid-wall elevated) is a simple flick of a on-screen setting using the supplied PC- or Mac-based software. Customization of these EQ and other crossover settings is also merely a function of a $100 calibration microphone and some shareware (i.e., REW, etc.).

 

"Lower price"-- The price of MEH drivers can run from a few 10s of dollars (USD) to thousands for the compression drivers used.  In general, the sweet spot for compression drivers for hi-fi use seems to be in the $200-$500@ range, and the price of a pair of woofers in the $200-$300 range. 

 

The price of the box containing the MEH and forming an infinite baffle for the woofer backwaves is about the same as other mid-to-low price hi-fi loudspeakers. 

 

The price of the DSP crossovers that would have acceptable performance is about $100 (per loudspeaker) or $200 (per stereo pair)--up to $2K-$3K.  The best units for the job seem be gravitating toward the $200/unit (serving two loudspeakers). 

 

Powered loudspeakers (i.e., with DSP crossover and supplied amplifiers) can easily be an option, and a simplification for the end users that do not wish to tinker with amplifiers and their differing relative throughput gains.

 

The price for PA versions of the MEHs that would be tangentially applicable to home hi-fi use (the Danley SH-96) is $8600+ each.  That's a bit high for the home hi-fi market, especially considering their "industrial looks".  The SH-69, which has a coaxial driver and separate woofers, retails for over $4800, and comes in basic black.  I would not consider this to be a "home hi-fi" version because of the listening performance of that coaxial driver.

 

"Easy to Buy"-- Because of the current state of affairs, this is currently the limiting factor--along with the realization that there really are no MEHs being sold for home hi-fi use.  I believe that's going to change over time.  Part of the "easy to buy" category is the ability of potential buyers to hear the loudspeakers in use.  That is also an area that has proven to be slow to change.

 

Chris

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As a guy who has owned 16 of the original Unity Summation Aperture horns, I have retained 4, which will be used as surround channels when I repaint them. One of the things that is worth mentioning is that they are Arrayable. IOW, if you take 2 of the 60x40 horns, they were designed to be butted together when you want greater dispersion angle. This double the mouth size, lowers the bass response, and gives you 80x60 degrees of dispersion, but you need 4 to do 2 channels that way (primarily how they are used in commercial applications). At the apoint the blend together as a single horn with better bass. The older design in the original patent was a sealed horn, whereas, the newer Synergy Horns use Reflex ports. The Passive networks are a work of art on an FR-4 Printed Circuit Board and weigh about 7 lbs. each (with lot of parts).

MEHnetworkWEB.jpg

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Yes, work of art...they are complicated passive networks.  When you see what those networks are doing to the output of the drivers, you might see what the "magic sauce" is...for the SH-50.  It certainly isn't a typical three-way crossover design--by any stretch of the imagination. 

 

For those of you that haven't figured out what the Danley Synergy SH-50 crossover is optimized for--it's designed for minimum phase growth as its first requirement, then flat frequency response as its second requirement.  It's the most interesting design of a crossover that I've personally seen.  It's very surprising--and its principle of design yields the best sounding multiway loudspeaker that I've heard (as applied to Jubilees or K-402-MEH, for instance)...and is completely the opposite approach of what everyone else is apparently doing nowadays with crossover networks--passive or active.

 

Chris

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Here is the SH46 network these are setup to use passive or bi amp . 

 

IMG_4730.jpg

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SH-50 specifications:

Coverage Pattern ....................................... 50° horizontal x 50° vertical
Operating Frequency Range ....................  50 Hz - 18 kHz +/- 3 dB
.................................................................... 37 Hz – 24 kHz -10 dB
Sensitivity @ 1M ......................................100 dBSPL
................................................................... (Measured as 2.83V input, 1M whole space)
Maximum Output ....................................127 dBSPL Cont.,133 dBSPL Peak
Input Power Ratings ......................... 1000W continuous, 4000W Peak
Nominal Impedance .................................. 4 ohms
Minimum Impedance ................................ 3.5 ohms @ 1 kHz
Recommended Processing ................... 40 Hz HP @ 24 dB/Butterworth
Drivers ..................................................... LF 2 x 12”, MF 4 x 5” HF 1 x 1”

Dimensions (in.)......................................28 x 28 x 25.5

Weight...................................................133 lbs

 

SH-46 specifications:

 

Coverage Pattern ................................... 40° horizontal x 60° vertical
Operating Frequency Range .................. 71 Hz – 14.5 kHz +/- 3 dB
................................................................. 58 Hz – 16 kHz -10 dB
Sensitivity @ 1M .................................. 106 dBSPL (Measured as 2.83V input, 1M whole space)
Maximum Output ..................................135 dBSPL Cont., 141 dBSPL Peak
Input Power Ratings ........................... 1400W continuous, 5600W Peak
Nominal Impedance .................................4 ohms
Minimum Impedance ........................... 3.4 ohms @ 810 Hz
Recommended Processing ................... 60 Hz HP @ 24 dB/Butterworth
Drivers .................................................... LF 2 x 12”, MF 4 x 4”, HF 1 x 1.4”
Dimensions (in.)...................................... 29 x 22.3 x 22.7

Weight..................................................... 118 lbs

 

As you can see, the output levels of the two MEHs by Danley are very high (127 dB, 135 dB music power), and as a consequence are three-way designs using seven separate drivers.  They are both designed for "arrayability", i.e., stacking two or more units together to cover more angular arcs.  In the case of the SH-50--it's 50 degrees each axes (hor, ver), and the SH-46 is 40 degrees horizontally and 60 degrees vertically.  These are probably not the requirements that I would design to for home hi-fi use (but I'm sure that the two models sound very good nevertheless). 

_____________________________________________________________________________________

 

Notional Design Requirements for Home Hi-Fi MEHs

 

  1. In my view, the design requirements should include wide horizontal coverage of at least 80-90 degrees, and at least 60 degrees vertically (in order to avoid pattern flip of the polars below some operating frequency).  FYI, the K-400 series midrange horns (including the K-500. 600, etc.) from the Klipsch Heritage series begin to experience pattern flip below about 2-->2.2 kHz due to limited vertical mouth dimensions.
     
  2. Additionally, I'd recommend minimizing the number of crossovers and drivers--to two woofers and one 2" compression driver in a two-way operation.  This will simplify the crossover by 50% or more, and offer even better smoothness and inherent time alignment than a three-way design.  If necessary to use three-way, using a dual-diaphragm compression driver (like the BMS 4592ND) bi-amped is definitely the way to avoid breaking up the MEH into two or more horn apertures (i.e., separate tweeters are not desirable), or employing midrange drivers to bridge any woofer-tweeter frequency response gap, which also adds significant physical complexity in terms of mechanical clearances, disruptions in polar coverage at 1-2 kHz, and having to add more PEQs to compensate for the 1-2 kHz crossover frequency on the multiple-entry horn.  The two-way requirement (or using dual-diaphragm 2" compression driver)  dovetails nicely with the maximum SPL output requirement, discussed next.
     
  3. The output levels required by home high-fidelity loudspeakers is more like 120 dB operating (for Klipsch horn-loaded users) and probably 110-115 dB by others that have imprinted on direct-radiating two channel operation.  I think 120 dB is a good design point.
     
  4. There is no requirement to array MEHs for home hi-fi operation.  This releases the requirement for arrayability, which affects the design parameters for the horn itself, and the phase/frequency curve characteristic, and an implied requirement for passive crossovers for outdoor PA use in remote installation locations.  [The DSL Synergies have been designed for arrayability (and SPL) as perhaps the highest priority/precedence requirements.]  Realizing that arrayability is not needed opens up the MEH design approach to other less intensive design and fabrication approaches for the crossover networks, and really opens the door to using DSP crossovers instead of passives. 

    This increases the MEH design space fairly dramatically, allowing for optimization of polar coverage and minimizing impedance bounces in the horn/driver assembly for home hi-fi use.  It also reduces to the design complexity by probably an order of magnitude, and permits even flatter phase and group delay plots, and almost perfect step response (using FIR filters available in something like a single miniDSP 2x4HD crossover [$200 for two stereo loudspeakers] which support FIR filtering to completely flatten the phase and group delay plots above 200-300 Hz...or perhaps lower frequencies).

 

Chris

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So the bottom line on MEHs designed and built for horn hi-fi duty is that they will:

  1. look different than Danley designs (i.e., they will probably incorporate nicer finishes and perhaps incorporate horn veneer, be less deep, and have a wider mouth)
  2. have significantly more operating flexibility with their inherent room EQ/boundary gain (even including excellent corner-horn performance if that's desired),
  3. cost significantly less than Danley products,
  4. have more hi-fi sound, perhaps that rivals any loudspeaker that the user/owner has ever heard,
  5. be significantly smaller than a Khorn or Jubilee--at about La Scala II size or slightly wider/taller, but form-factored to fit into room corners much better
  6. also perform very well as studio monitors due to their outstanding impulse response, frequency response flatness, almost perfect step response, controlled coverage (horizontally, vertically), and much wider frequency response, especially low frequency response down to sub-30 Hz.

Chris

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@Chris A 

I thought now would be a good time to Thank You for the information you regularly provide.

I never comment because it's better to let them think I'm stupid than to open my mouth and prove it.

Truly Do want to say thanks  because even when a subject goes over my current understanding you try to make it easier for people like myself to understand. Even when I don't completely grasp the info provided , I am thinking and thus growing. There a several others here that also do this and really what a great benefit to us all !

                                                                                                                         Thanks

                                                                                                                                       Gary

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2 minutes ago, Gnote said:

@Chris A 

I thought now would be a good time to Thank You for the information you regularly provide.

I never comment because it's better to let them think I'm stupid than to open my mouth and prove it.

Truly Do want to say thanks  because even when a subject goes over my current understanding you try to make it easier for people like myself to understand. Even when I don't completely grasp the info provided , I am thinking and thus growing. There a several others here that also do this and really what a great benefit to us all !

                                                                                                                         Thanks

                                                                                                                                       Gary

 

Yup!

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49 minutes ago, Gnote said:

@Chris A 

I thought now would be a good time to Thank You for the information you regularly provide.

I never comment because it's better to let them think I'm stupid than to open my mouth and prove it.

Truly Do want to say thanks  because even when a subject goes over my current understanding you try to make it easier for people like myself to understand. Even when I don't completely grasp the info provided , I am thinking and thus growing. There a several others here that also do this and really what a great benefit to us all !

                                                                                                                         Thanks

                                                                                                                                       Gary

Indeed,

 

Every time I contemplate a new speaker project I return to these threads here and on diya that Chris has started. I do not have the knowledge to implement a MEH project on my own, but I believe the MEH will be the ultimate speaker. I just can’t justify any other speaker to replace my diy la scalas. I really hope the MEH project develops into something within reach. 

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Thanks guys.  It's not always clear to me that threads like this one are effective in conveying the ideas of (in this particular case) new loudspeaker design approaches.   Your comments let me know that there's an audience that's reading and has interest.

 

I should take just a little break to explain why Klipsch doesn't presently produce MEHs: it's all about the legal uncertainties of the basic ideas, and perhaps a little having to do with "not invented here" (NIH):

 

When you look at the development of of the first electrically-driven loudspeakers around the time of the "talkies"--motion pictures with sound which occurred ~1930-1931, there were similar issues of patent protections and "NIH"--not invented here.  Western Electric--the engineering arm of the Bell Telephone system at that time--first produced the now-famous WE horns having very large dimensions, very high fabrication costs (welded steel horns of folded and/or curved horn construction), extremely high weight, very limited polar (audience) coverage and similarly limited low and high frequency response capabilities. 

 

WE_Horns.JPG

 

Later on, there were innovations by MGM led by two men: Shearer and Hilliard (of Shearer Horn fame)...

 

shearer5.jpg

 

...which directly led to the Altec Voice of the Theater (VOTT) series of loudspeakers with greatly improved cinema coverage and frequency response performance, much lower fabrication costs and weight, and lower demands on the driving electronics (amplifiers, preamps, etc.).  This led to the "golden age of cinema":

 

1975-vott.jpg

 

While all this doesn't appear to apply to home audio, I think that many horn aficionados today see the connection to real hi-fi beginnings.  For many years, the home hi-fi scene has been dominated by Ed Villchur's small "acoustic suspension" (closed box, infinite baffle) direct radiator systems (Acoustic Research Corporation and others) as the costs of power electronics began to fall, and later on, the rise of ported-box bass bin loudspeakers.  These loudspeakers made home hi-fi affordable and economically realizable for the small room sizes that were typical of the new "suburban" homes and small high-rise city apartments of that time. 

 

edgar-villchur-300w.jpg?w=474

 

Since that time (late 1940s-early 1950s), there has been the realization by some consumers that direct radiating boxes didn't have the same feel and experience of "being there" that fully horn-loaded loudspeakers provided in commercial cinemas.  This was the cue for Paul Klipsch's corner horn to arrive on the scene: the Klipschorn.  During those days of mono, a single Klipschorn in one corner of the room brought that "excitement" potential to those hi-fi enthusiasts that could tell the difference between direct-radiating small loudspeaker sound and fully horn loaded "live sound":

 

3007764323_d16bb26a10_b.jpg

 

Ever since that time (late 1940s-1960) there has been a tension between the "small loudspeaker" buying public and the horn-loaded enthusiasts.  The year 1960 brought with it the innovation of stereo records and stereo loudspeakers.  Instead of one loudspeaker, you buy two and set them up in identical twin pairs.  The increase in realism of the performance was undeniable.  Thus, the real birth of home hi-fi that rivaled commercial cinema sound systems began in earnest:

 

khorn2.jpg

 

One of the most important advantages of the MEH design discussed here is that it brings the fully horn loaded sound back to the technical/subjective listening forefront of high fidelity--and in an even smaller package than corner horns.  The rest of the story about the "why" of MEHs is now put into better perspective, above.

 

New Center profile 500px.jpg

 

Chris

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Thank you Chris.  I posted somewhere else that, were I to replace my DIY "Super Hereseys," supplemented by 4 DIY Anarchy Exodus TH subs, DIY MEH would be my choice.  I've listened to Claude's @ClaudeJ1 MEH system.  All that you say is accurate.

 

Due to being 70, with limited space, I doubt that I'll grow dissatisfied enough with what I have to build new speakers, but if I do. It'll be a MEH based system.  

 

Please keep educating us about MEHs and mastering issues.  Thanks.

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7 hours ago, DizRotus said:

Thank you Chris.  I posted somewhere else that, were I to replace my DIY "Super Hereseys," supplemented by 4 DIY Anarchy Exodus TH subs, DIY MEH would be my choice.  I've listened to Claude's @ClaudeJ1 MEH system.  All that you say is accurate.

 

Due to being 70, with limited space, I doubt the I'll grow dissatisfied enough with what I have to build new speakers, but if I do. It'll be a MEH based system.  

 

Please keep educating us about MEHs and mastering issues.  Thanks.

You'll like the latest setup even more. Chris is really on to something here!

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I'll toss in a thank you as well. I spent a lot of time a year or so ago reading and re-reading Bill Waslo's pages on his synergy horns. Chris recommended them again and some things are starting to make sense. Chris makes it easier to understand... and I've shared some of my own thoughts with him. I have a long way to go, but I'm in for the concept no matter what.

 

Bruce

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On 2/14/2019 at 8:04 AM, Chris A said:

Currently, there are legal issues that surround their design and production, but in general, the originating patent (US6411718) has expired, "prior art" is the controlling legal principle, and any other later patents will not be able to legally constrain free use of the design. 

The application has expired TODAY, but officially not expired until April 28, in about 6 weeks and 3 days. This is for the sealed woofer version, not the ported, modern ones.

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1 hour ago, ClaudeJ1 said:

The application has expired TODAY, but officially not expired until April 28, in about 6 weeks and 3 days. This is for the sealed woofer version, not the ported, modern ones.

It actually expired on August 12 2014 due to non-payment of fees (back dated to 6/25/2014).  The Google patents date at the top of the patent page is actually in error (in terms of interpreting what it's saying) and also referring to the 20 years expiration date based on application date and time: 28 April 1999--which occurs in about 6 weeks (...a moot point). 

 

Chris

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I have some old Unity prototypes (old enough to see where there was experimentation on placement of the mid driver ports) - extremely "coherent". (moreso subjectively than my FR stuff)   With constant directivity characteristics over 60x60 angle with DE25,, I'd guess its sensitivity ~100dB.  For the low end - how much horn action are we getting in Synergy cabinet that's a manageable size and weight?  What do hornresp sims say for some Synergy in that regard?  (I'm/beat - be happy to catch up with Saul White and Abe Cohen with their "Classic")

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Add my thanks for your work on MEH loudspeakers and for explaining clearly the "hows" and "whys" of the design. You have a gift for explaining highly technical things in a way that is easy to understand. Keep up the good work!

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1 hour ago, Don Richard said:

You have a gift for explaining highly technical things in a way that is easy to understand.

Thanks.  I got to practice over 35+ years of an engineering career (including ~7 years adjunct teaching graduate students), so perhaps it's more about elbow grease than talent.

 

Doing audio for the past 5-10 years has definitely sharpened the skills.  :wink:

 

Chris

 

 

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