Help the Ijit write Ijit's guide to Danley tech

[Author's revision] I propose to re-name this thread "The Ijit's Guide to Unity and Synergy type speakers". At least until other users give up on me, or I'm banned from DIYAudio, or (most likely) my Synergy Fever runs its course, I propose to annotate my ravings and ramblings in this thread, rather than pollute existing threads as has until now been my modus operandi :)

Those who know me know that I qualify as an Ijit :) Seriously, I am as fascinated by Tom Danley's inventions as I am inept to duplicate them :rolleyes:

I do have writing skills, somewhat, and would like to make a relatively brief summary of Danley's inventions as they apply to his horns (perhaps add the tapped horns later).

I am slowly worming my way through the various Unity, Synergy, Cosmic Energy etc. threads here trying to to comprehend stuff.

I have tried to read some patents -- a challenge in itself -- and even a translation from "Patent-ish" to English would clarify much.

Below is my Rev 0, an outline if you wish:

Danley's "full range" horns (excluding his tapped horn inventions) generally fall into three categories, shown here by their patent numbers and given official or unoffical names:

4845759 1989 Named? = multiple drivers in one horn; coherence is achieved primarily by active electronics EQ-ing individual signals for a desired composite output.

6411718 2002 Unity: this is the one that uses two or more drivers; the type of driver, the chambers, cavities, etc. are a factor in this design. This appears to be the most popular design to attempt to DIY.

8248976 2012 Synergy? (I still don't understand this one.)

8488826 2013 Layered Combiner [?] When complex milling of solid metal is not sufficient, instead use a mind-boggling stack of individually shaped metal plates with individual channels to do the same thing (or more complex manipulations?)
 
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Those who know me know that I qualify as an Ijit :) Seriously, I am as fascinated by Tom Danley's inventions as I am inept to duplicate them :rolleyes:

I do have writing skills, somewhat, and would like to make a relatively brief summary of Danley's inventions as they apply to his horns (perhaps add the tapped horns later).

I am slowly worming my way through the various Unity, Synergy, Cosmic Energy etc. threads here trying to to comprehend stuff.

I have tried to read some patents -- a challenge in itself -- and even a translation from "Patent-ish" to English would clarify much.

Below is my Rev 0, an outline if you wish:

Danley's "full range" horns (excluding his tapped horn inventions) generally fall into three categories, shown here by their patent numbers and given official or unoffical names:

A)4845759 1989 Named? = multiple drivers in one horn; coherence is achieved primarily by active electronics EQ-ing individual signals for a desired composite output.

B)6411718 2002 Unity: this is the one that uses two or more drivers; the type of driver, the chambers, cavities, etc. are a factor in this design. This appears to be the most popular design to attempt to DIY.

C)8248976 2012 Synergy? (I still don't understand this one.)

D)8488826 2013 Layered Combiner [?] When complex milling of solid metal is not sufficient, instead use a mind-boggling stack of individually shaped metal plates with individual channels to do the same thing (or more complex manipulations?)
DSLs white papers explain much of the above in simple terms:
White Papers | Danley Sound Labs | Danley Sound Labs, Inc.

"A", "B" & "C" are various iterations of the same concept, multiple drivers sharing the same horn to achieve the equivalent of a single point source, delivering uniform, constant directivity down to a frequency determined by mouth size- the larger the mouth size, the lower pattern control extends.

"D" is an approach to couple massive quantities of high frequency devices on a single horn while retaining phase coherency and (relatively) low throat SPL. Tom developed the Layered Combiner some time after I pointed out to him that HF air absorption rendered the HF content above 5-10kHz of his stadium devices anemic by comparison to the prodigious LF/MF output they were capable of.

Tom has mentioned the Layered Combiner (AKA "Mosquito Beater") was one of the most challenging devices he ever designed, saying quite a lot for a guy that has made acoustic levitator devices and blower operated subwoofers capable of wall bending response down to a few Hz.

Unfortunately, although the Layered Combiner does achieve tremendous HF output, the variability of thermal gradients render delivery of HF at great distances a "hit or miss" proposition. Thermal gradients are constantly changing, and can redirect the short VHF wavelengths to the point where they completely miss the intended target, which can result in "collateral damage" when they drift on to the playing field or over the fence into the neighborhood.

Fortunately, those problems simply don't exist in typical domestic environments.

Art
 
Thanks for the source material.
I'd also suggest mining Live Audio Board/Pro Sound Web for source material, discussions go back a lot further than here, with lots of info scattered through the LAB days into the Unity to Synergy and Tapped Horn transitional eras.

Art
 

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Why do we low-pass the mid driver?

If anyone would like to clarify this, please do.

On a Synergy type horn, two of the driver selection challenges are:

Finding a HF ("tweeter") that goes low enough, apparently needs to be useable down to 1000 Hz or even lower. This is a challenge expecially for a compression horn, less so for a full range as done in some not-strictly-Danley-ripoff horns :)

I can understand the above; you don't want the HF operating at the bottom of its range due to increased distortion produced. But I is more confused about...

Why do we want to keep the midrange (usu. a pair or more of cone drivers) low-passed? Most midranges can go well above the 500 or 1000 Hz that people seem to be specifying for the crossover to the HF. Wouldn't raising the x-over to 2K, 3K make life a lot easier on the tweeter?
 
In a way, you've answered your own Qs, i.e. the tweeter's and mid-range's pass-band is not 'writ in stone', just for making a particular DSL 'clone'.

For instance, if I ever get around to making a 'serious' Synergy concept, it will be designed around Altec compression drivers, which requires a considerably different set of design parameters, consequently couldn't be successfully used on DSL's or similar/same concept clones even with considerable digital EQ, I'm guessing.

GM
 
GM, thanks. There are so many "synergy" threads going, that I can't remember what I've posted where. Perhaps I can use this one as my "isolation ward" until my current fancy fades. What next? Hmmmm, I've never tried a plasma tweeter (Joking!) :clown:

Xrk971 seems to be the "go-to guy" when it comes to synergy clones here. Since others have [had success?] cloning different scales of his design, my latest whim is simply to make a 2x of his "standard" Trynergy. I am going to price large (4x8') sheets of bendy stuff at Lowe's Depot :) this afternoon; if I'm going to build, why not big? Basically I want to see how big a box I can make, hopefully with just the ubiquitous straight-edge and razor knife :) Yes it will be weak, need CLD etc. but in this hobby the whole goal is to build ever-evolving prototypes :rolleyes:

A more practical aspect of a 2x Trynergy is a cutoff more compatible with existing subwoofer.

Sent from my NV570P using Tapatalk
 
On my Synergy version, I used a tweeter CD that is only really usable down to 2kHz, and the crossover I use is around 2600Hz if I remember correctly. I used that tweeter because of its throat angle of 30 degrees to be closer match for the horn and extended response. So, LF capable tweeter CDs aren't an absolute necessity (but crossing higher forces you to push the midrange ports closer to the throat, which pushes toward using smaller midrange drivers -- I use 2 inchers)
 
I am pricing possible source material at a noted big box home improvement store that has free Wi-Fi. I think even X's beloved foam board is too expensive at about twelve to $20 for a 4 by 8 sheet. advantage: you can get it in silver or pink if that's what you want. [emoji41] I have seen hardboard or very thin veneer tight board for eight or $10 a sheet flexible which probably need for making the panels and of course more more stronger thicker things cost a bit more but that's cheap cheap cheap so I need to get the plans and scale up and start cutting. Probably, even a cheap driver cost more than the paneling materials for one of the speakers!

Sent from my SPH-L300 using Tapatalk
 
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For instance, if I ever get around to making a 'serious' Synergy concept, it will be designed around Altec compression drivers, which requires a considerably different set of design parameters, consequently couldn't be successfully used on DSL's or similar/same concept clones even with considerable digital EQ, I'm guessing.

GM
GM,

There is nothing in the concept of using HF compression drivers and offset mid(or low) drivers on a shared horn that would preclude using Altec compression drivers, even using passive crossovers (as DSL does).

Using passive crossovers does require more attention to design details than using DSP, which can easily accomplish smoother frequency response in a fraction of the time required for passive crossovers, and eliminates power wasting resisters, for a more "green" friendly build ;).

There are at least two DIY members using 2" exit drivers crossing to 15" cones on the same horn.
I have used 3" diaphragm 1.4" exit drivers crossing to 10" cones.
DSL uses 1" exit drivers with 8" cones in some of his designs, although more typically small mid cones and additional woofers are used to reduce the excursion of the HF driver so it can reach the SPL required for PA use.

For home use, where SPL typically doesn't exceed 110 dB at one meter, driver requirements are considerably relaxed.

Art
 
Agreed and have posted similar elsewhere, but you miss my point in that the system requires designing from scratch and not be tempted to use/copy any of the DSL's as a 'close enough' choice; and yes, I plan to use DSP, though not in the 'ham fisted'/brute force way some have done.

Not that I'm 'trashing' those who do as it's ~ what I did to cobble together a POC way back when Tom told me about the Unity; just want to make it as technically correct as I know how to and 'it is what it is' to adapt as required in new alignments if I pursue it further. The way 'things' has been going since 2000 though, it's probably not going to happen :(.

GM
 
If you say so :)

On a slightly more serious note, since the only software tool I know at all is Hornresp, I want to model an example of a successful horn before I make mutants.

I'm still planning to make a version of xrk971's Trynergy, the 1x scale if the following is not easily answered:

Since the dimensions for this tractix horn have been established, I am assuming that the design can scale down (he has a smaller version) or up (he did mention a 2x version), within reason. I am also assuming that the driver(s) would change and that is where it gets cloudy :) I will hunt up the "2x" threads and see what drivers were used. Aw, what the heck? xrk971 is such a good guy that he seems to run a sim for anyone who asks him :)
 
Random thought #1

Since this thread is my "isolation ward" I will try & post my musings here. Your replies, if any, will be as "stream of consciousness" as my wandering thoughts. In other words, just like any major thread here at diyAudio :rolleyes:

Premise: best to avoid crossovers in the mid-range, but unfortunately that is where they usually must be. Granted that the ideal crossover-less range would be something like 300 to 3000 Hz; even though many mids can do that, is this so for a horn? Yes I am sure, but I get that many designs cross at 1000 Hz or less, because this reduces harmonic or other distortion that otherwise arises from a mid going too high or the poor tweeter going too low.

Everyone knows that a crossover in the mid-range is the Work of Satan :darkside: and thus something to avoid...?

In shopping for drivers, how available are plots of harmonic distortion against frequency?

If the "avoid x-over in this range" idea is valid, then a goal should be to find the highest x-over frequency vs. acceptable low distortion.
 
Premise: best to avoid crossovers in the mid-range, but unfortunately that is where they usually must be.
1)Granted that the ideal crossover-less range would be something like 300 to 3000 Hz; even though many mids can do that, is this so for a horn?
2)Everyone knows that a crossover in the mid-range is the Work of Satan :darkside: and thus something to avoid...?
3)In shopping for drivers, how available are plots of harmonic distortion against frequency?
4)If the "avoid x-over in this range" idea is valid, then a goal should be to find the highest x-over frequency vs. acceptable low distortion.
1)Well designed horns can cover a decade or more. As you have seen, a 3.5" Tymphony TC9FD-18-08 "full range driver" on the Maltese horn covers well over a decade from 250Hz to 20,000 Hz with low distortion at domestic listening levels, though the 25x25 degree high frequency pattern would require more than one per side to cover a couch width seating area at typical domestic distances.
2)Crossovers are used to divide components into the frequency range they work well in for the intended SPL output, nothing "Satanic" about the pursuit of good sound. Well executed crossover transitions are seamless, and impossible to detect, regardless of frequency of transition.
As a "guide to Danley tech", most of DSL's product line contains crossovers in the 300 to 3000 Hz range.
3)Seldom available, and the HD plots won't tell you how that driver will perform directly driving a horn, or when used as an offset driver in a horn. Xmax x Sd will give you a good idea of output potential, distortion will generally be acceptable if the driver does not exceed Xmax. The TC series driver you recently selected has a bit more than half the Xmax as the TC9FD-18-08, so you can expect about 5 dB less output, or conversely about an octave higher crossover point for the same distortion.
4)The "avoid x-over in this range" idea is valid if the crossover will not be designed properly, though your goals then would be to find the widest mid-high bandwidth with acceptable low distortion, and one of the primary purpose for a horn- pattern control to cover the intended listening area without covering unintended areas.

Art
 
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A conspiracy?

Weltersys, thanks for some good points and my comments, which only give the impression that I can type 60 words a minute but think only about twenty :)

(1) I will look at the Maltese again. For those of us considering a horn smaller than a typical suburban house's garage, or the Armageddon or whatever Danley's top model is :) , the consensus seems to be that reaching 200 Hz or so is achievable, and makes crossover to the sub (preferably of course a Danley TH!) Also the fact that the Maltese can serve as a picnic table is a recycling plus :)

(2) and (4) Allusion to devil is only allegorical (except when you are looking in the details.) The crossover should be a non-issue today, for those like me who would stoop to the easy way out of DSP (MiniDSP et al). :) I've never tweaked a home-built speaker, outside EQ-ing my sub. Even the lowly MiniDSP can probably do a lot, and it's pretty basic compared to the more advanced tools out there (convolver, etc.)

In the thread I reference below, they discuss the x-over issues. It occurs to me (probably not original and I read it here...?) that having DSP allows much experimentation and maybe to correct for, ahem, sloppy construction that certain hacks such as myself might be guilty of :)

(3) I will go with the recommandations of those who actually build and test stuff here. It's unlikely I'd ever push even a small horn hard enough to distort, even if I used one of those horrible floor-sweeings drivers I tend to purchase from MCM cause they're cheap :)




Ran-dumb thought: Danley has provided so much support to diy over the years, that it'd be a pity if we did not invent him a Synergy horn suitable for the home market, that he could market under his patents :)

Here is the excellentest thread I've found in a few days:

http://www.diyaudio.com/forums/multi-way/241976-synergy-horns-no-drawbacks-no-issues.html

Speaking for myself, I have plenty of "issues" but none relating to speaker design :clown:
 
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