There's a difference between frugal and inadequate. Are you familiar with the Matterhorn? Does it seem weak? And I'd use a lot more bracing than the none that Danley used.
The Matterhorn is an interesting sub regardless of the fact that it's a huge marketing gimmick that I doubt was ever built for the reasons stated (military use). The "making of" video is a 10 minute commercial for DSL and tapped horns, even having the audactiy to suggest that no other alignment could produce that type of output in that size. Pure BS - a simple transmission line could do the same thing since I don't recall flat response to a high frequency being a requirement. Even making it a huge ported box would do the same spl, although it would require more power.
But the sub itself is interesting. Watch the video if you haven't seen it already. It's not a weak enclosure.
Unless it was built before 1996 there were plenty of sim tools. They could have used Akabak. I seriously doubt that horn predates 1996.
Yes, I saw it. And I actually read what was said about it, particularly the part where the designer basically stated in detail that he didn't know what he was doing.
And yes, I saw that someone mentioned it was measured. The only thing said about that was that Response was down to below 20hz (measured), though it was theoretically a 30hz horn, which further suggests that he had absolutely no idea what he was doing when he designed it. How do you miss your tuning by over half an octave? Incompetence.
Give that thread a reread. He makes several comments pointing to the fact that he is clueless about horn design, he didn't simulate it, he had no idea what effect porting the rear chamber into the horn flare would have, he thinks a full sized horn with a carefully calculated expansion is almost a little silly if the mouth is resting on the ground. He even said very specifically I just calculated the throat, mouth and length, and hoped for the best. Do I need to go on? Because I could. He had no clue at all.
I could probably have a toddler draw a picture of a horn on a napkin and build from that crayon drawing and get results as good as this guy's horn. Seriously, if he measured it, where are the measurements? Just because he said it was great doesn't mean anything at all, in fact considering his blinding incompetence it actually devalues his opinion.
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The planning for the horn was done on paper.
Dunno the build year, definitely pre 2000, possibly pre 1997.
a) if I recall correctly, the horn was burned after use
b) the festival changed and got more rules in 1997 (e.g. "Burning your own art must be done on an approved burn platform")
...but maybe the horn was built in 1999, and Greg B simply wasn't an early adopter of Akabak.
Nicely put and very funny
However now != the 90's. And the thing worked.
The OP asked (back in post 14):
...and that's exactly what this was, straight and exponential, if not quite a 20Hz horn.
I'd love to see that. However, in a 2001 post, Greg B said:
"yeah, well i was emboldened by ignorance as usual. it started out as just a folded baffle to control directivity, and then we kind of got carried away. mouth is 8ft sq, throat is ~ 16-17 in sq i think. basically it is roughly exponential, or as close as possible given two days of labor and reasonably economical use of standard size plywood. it uses an altec 811 horn for the highs.
sound quality was great. really loud and low distortion. made the ravers' rows of multiple 4 x 15 cabinets sound like mushy overpriced ghettoblasters."
...which is all the dimensional info one needs to duplicate it, and a bit more advanced than a toddler's crayon picture.
Seriously?
Imagine that it is 1996. Imagine you've spent a few thousand on a sweet laptop and measurement mic. Imagine that you are going to Burning Man. Imagine that you expect:
1) The Black Rock Desert to be a "desolate surreal trackless plain"
2) No (or limited) policing
3) You will be living in a tent for a week
4) You will be drinking
5) There will be crazy people, some of them armed
Would you take along and set up your measurement gear, thereby displaying to anyone passing by that you had portable, high value items stowed in your tent?
Based on the descriptions we do have (and which were based on direct comparison to PA stacks that were also right there), it does seem like this horn delivered exactly what the OP was asking for. Which is good, and exactly what you'd expect a big low-compromise front horn to do. And the OP could always add a bit of fudge factor (quadruple the drivers, add wings, scale the whole thing up a bit) to be sure to avoid disappointment.
I think Greg B was being a bit tongue in cheek with his disclaimers. He also wrote (in 2001):
"I have plans somewhere, I'm not quite as subjective as I seem to come across. Unfortunately, I have no idea where they are. This seems to be a hazard of using the old drafting table rather than a computer for drawing."
I hadn't watched it before, so thanks. My headphones don't do it justice, but I'm sure it is a totally boss sub.
There is bracing, I think. At 2:40, they've completely covered the interior with a skin of ply (which would account for 20 of the 53 sheets used), and have attached several long bits of steel to this, running lengthwise. At 2:55 and 3:25 I think you can see a matrix of steel connecting the back of the driver boards to the steel on the container walls.
...and all through the video, they seem to be using power tools in a small space, without any hearing protection. Eek!
...or instead of using a horn that's been folded in half to meet their 20' (portability?) requirement, you could build a straight horn in a full-sized 40' container.
This is no excuse at all. Leach's horn paper that I keep mentioning was published in 1979, and for the most part it's regurgitated formulas that are almost a century old.
I'm infamously bad at math and even I went through the paper and figured out the formulas.
If he was serious he could have done this.
Nicely put and very funny
However now != the 90's. And the thing worked.
Of course it worked. Everything works to some extent. The issue is how well it worked and I doubt it was anywhere near ideal, probably not even good.
OP was specifically asking for personal experiences, the only person that heard that horn was the guy that designed it and based on his design notes he's clueless about how to evaluate a horn. And seriously biased, since he's the designer and builder. Everyone at burning man thinks their system is best. Read a few reviews, every single one will say their system was awesome and everyone else's was terrible. If there was a stack of 8 Labhorns sitting right next to his horn I'm pretty sure he wouldn't have been so glowing in his review of his creation, as his own horn wouldn't be audible over the Labhorns. (The Labs were designed near the turn of the century though, so if his horn predates that the comparison would have been impossible.)
Not much.
Yes, seriously.
Imagine that he measured it at home before taking it to burning man. Imagine that he was proud of his creation so he made some type of record of the measurements.
Instead, back in reality, I imagine that the only "measurement" he did was playing a few test tones and listening to what came out.
The owner's subjective opinion means absolutely nothing at all.
This was absolutely not a "no compromise" horn. The first and foremost compromise is the designer and his complete lack of competence for this task.
I'd like to see the plans if he can dig them up. Then it can be easily simulated and we can see just how bad it really is.
My containers are both full size. The extra length would allow for a lower tuning, but it's not going to happen.
JAG,
Tom Danley simply reproduced his SDL BT7 design from the mid-1980s as the LABhorn, after he had determined one could get a lot more "bang for the buck" using "tapped horns". There are good business reasons he "gave away" the LABhorn design, but has not been quite so generous with revealing the TH designs.
The BT7 was an upgraded version of the BT5, which was a redux of Cerwin Vega's original 1970's Earthquake folded horn, which were based on centuries old horn knowledge.
Although I have fond memories of standing in front of walls of horn cabinets shaking my guts, like most nostalgic trips down memory lane, the memory simply reminds me of a bygone era when horns were the cheapest way to achieve that high impact SPL.
The advent of drivers with displacement equivalent to ten drivers of that era, capable of handling the power needed to push that much air, for far less cost, has pretty much made those memories a historical footnote as far as I'm concerned, but it was a hell of a time!
Art
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....I have a great amount of respect for your input on these matters, you were on the scene as all this was going down and actually had personal communications with Danley over the years. Your own personal experience in the field makes you a historically relevant figure whereas I didn't even have my own dial up internet connection until 2006 when I started to sporadically semi seriously study enclosure design. As such I don't want to insult you and I also don't know how far you want to get into the details of history the science of tapped horn vs other alignments but some of this is wrong and some needs major clarifications.
1. When Danley was creating the Labhorn he wasn't simply reproducing anything. It's true that he recycled concepts that he had used previously and that horn design math was around long before any of us but the Labhorn was a new implementation.
The Labhorn design notes I have don't start from the beginning. Danley even notes that it had been a long road in the first of the notes that I have, he was already folding the horn and the prototype driver had already been built, so the notes I have are from the tail end of the project.
Regardless even with what I have, you can see that the Labhorn was designed from the ground up, not a reproduction. If I had notes that went back to the beginning of the process I can almost guarantee that he used Leach's math to design the driver and the horn, as he has talked about Leach's horn model extensively in the past. Here's what I have though, this is the horn spec after simulation and tweaking of the theoretical ideal.
The horn (2, 12 inch drivers)
St = throat area = 80 sq ins (40 sq inches per driver)
Vb = rear chamber volume = 1530 cu in per driver (separate rear volumes for
each driver)
Vf = front chamber volume = 170 cu in per driver (volume between cone & throat)
Flare = 26.4 Hz, hyperbolic t = .5, path length = 126 inches (inc front volume).
I think you will notice that this is not a reproduction of anything, it's a new design from the ground up.
2. The "more bang for the buck from tapped horns" was the major marketing dogma, and it didn't pan out nearly as definitely as Danley tried to make people believe. Even in the Matterhorn (which is a pure marketing video) Danley is seen saying both sides of the driver are used. This led to the very real perception that both sides of the driver are used as fully summing over the whole bandwidth, even though there was always information available that said otherwise. This perception still lives to this day in some minds.
In the collaborative tapped horn thread Danley and Iand went back and forth for quite awhile with Iand saying that a tapped horn would not outperform an EQUIVALENT ported box. And he was right, if size is held equal a ported box is actually better. A tapped horn is essentially a transmission line with clever driver placing to fill in a natural dip in response. Therefore, all this garbage about the tapped horn being the most powerful solution is a bunch of marketing garbage.
Tapped horns do not outperform front loaded horns. If size is held constant they are ~equivalent, the front loaded horn might even have a small spl advantage but it would require more power than the equivalent tapped horn uses to realize it, and the driver must be able to handle the extra power. I can and have proven this with sims and I'm prepared to do it again if this point is argued.
Besides, look at the actions, not the words. For the few short years that the DSL marketing campaign was successful in persuading the majority of the population that tapped horns were the most powerful alignment available, they only produced tapped horn subwoofers for sale. Now MOST of their new subwoofer products are front loaded horns. And not even full size front loaded horns (modular, meant to be used in stacks) but massively undersized front loaded horns. If tapped horns are so great, why are most of the new subwoofer products from DSL front loaded horns?
While it is true that if size is massively reduced (say to the size of a TH118), it would be hard to design a flh with an 18 inch driver in a package that size, so the tapped horn is the obvious choice. But that's an extreme, if you go Labhorn size with a single 18 inch driver, you can make a tapped horn or a flh and they will have ~ equal performance, because size dictates efficiency, not alignment.
3. I'm sure there are great reasons he gave away the Labhorn design. Even in the Labhorn notes the tension and resentment between him and his boss was tangible. He very likely wanted to get out of his contract and making his boss angry would be a great way to do that.
Also, let's not forget that he hobbled the Labhorn design when he folded it with too small rear chambers. Whether this was an accident that was never corrected or done on purpose to ensure that his own commercial products would remain at the top of the pile is subject to opinion, I suppose.
4. To say that Danley has not been generous with TH designs I would think is an understatement, with the exception of the TH_ Spud "leaked" plans. It's not clear how these plans were released and Danley seemed fine with it, it's entirely possible that the "leak" was an inside job.
Danley has done more to confuse the public as to how tapped horns work than to help them understand. Most of what he says is marketing nonsense, like his direct quotes in the Matterhorn video. He's said that no other alignment with the same size and tuning could beat a tapped horn. False. All the hints he gives are cryptic and misleading. He hasn't given away any more than he absolutely had to in order to secure the patent application and a lot of what he's said in public has been very misleading or outright false marketing hype.
While I agree with the general sentiment that modern products are making it harder to justify the use of extremely large efficient enclosures, I'm not fully on board. Danley has made a modern business out of selling large efficient enclosures and there's a reason they sell - they work.
Your own Keystone horn shows that there is an advantage to getting as much efficiency as you can with the space you can afford. And once you need more spl than a single cab can handle, it becomes clear why bigger horns (modular or not) are just the ticket.
It's hard to beat Leach's math with any other type of alignment - assuming you use it intelligently and use an appropriate driver complement - like for example not putting a single 12 inch driver on a full size horn. If you have the space and need the spl, you can do a lot worse than Leach's math, and it's not at all clear that you could do significantly better with any other approach.
Jag,
1.You should be able to see from the reprint I posted that the BT7 is the same physical size as the LABhorn, and it's spiral fold is virtually the same as the LABhorn.
2. It has panned out well for me, and DSL has sold many tons of TH enclosures in a very saturated market.
3. Ian is correct, but it should be noted that "ideal" drivers for a TH and a BR alignment are not the same. It is true that slightly more output per given truck space can be achieved with BR alignments with the same low frequency response, but at double the driver, amplifier, speaker and AC cable and connector cost. Whether doubling cost for a very slight reduction of truck space, which may make the truck exceed it's weight rating is "better" is a matter of opinion. Having used FLH, TH and BR options, I am firmly in the "tapped horn" camp.
4. No argument from me regarding that point.
5. Note how long it has been since the Intersonics BDEAP (Boundary Dependant) horns were released, and how the current DSL BH FLH cabinet designs are simply revisions of that technology. The DSL DBH series are basically bigger versions of the BT7 design, taking advantage of the great B&C transducers available this century.
6. More likely Intersonics folding due to NASA projects no longer coming through the pipeline has a lot more to do with him sharing an old concept than any attempt to make his former boss "angry". Be aware that the pro audio portion of Intersonics was not their primary source of income.
7. I was easily able to reverse engineer most of DSL's TH designs from the exterior photographs of the cabinets in his product literature and the "bread crumbs" Tom has shared all over the internet. Tom also personally shared the TH-115/18 plans with me after some discussions after I had finished testing the Keystone. That said, with as many copycats as there are, he is not going to just give away trade secrets that will create more competition.
A competing McCaully quad 21" isobarik TH (called something else) is an example, fortunately it is a dog by comparison to DSL products, largely because their engineer was not as adept at following "bread crumbs" as he could have been.
8. DSL's primary markets are large houses of worship, whether the client's audience is worshiping their god or their sports team, they pay the bulk of the income stream. To have pattern control essential for even coverage requires large wave-guides, which when loaded with a plethora of drivers are also quite efficient.
Each doubling of cone area and cabinet volume results in an additional 3 dB gain, the line arrays that DSL competes against, and often win in the stadium market are nearly as efficient, but don't have as good pattern control because the enclosures are too small.
9.True, and it's lighter weight than an equivalent BR system makes my trailer exceed it's tire's rating limit by fewer pounds ;^).
10. Only if you can afford the SPL/trailer volume reduction. For Entropic Eric, size is not an issue, for most of us, it is.
11. True again, though I never bothered much with math, far easier to revise and incrementally improve known working designs ;^).
Art
The enclosure dimensions have more to do with truck pack dimensions than anything else. Almost everything produced for live sound strives to have dimensions divisible by 22.5 inches. And a common horn size for designs using 1000 - 1200 sq cm of Sd is a Labhorn size enclosure. Sticking to truck pack dimensions, if you made it smaller (decreased any dimension by 22.5 inches) it would be too small to work well and if you made it bigger it would be hard to physically handle. So it's hardly surprising the dimensions are the same in the Labhorn and BT7, it would be weird if they weren't.
The fold being the same also isn't surprising, based on the required path shape and length the snailshell fold is one of the best options.
And since the physics and math of horn design haven't changed it's not odd that they would have similar physical characteristics and dimensions for the horn flare.
None of this negates the fact that the Labhorn was designed with theory and math from the ground up to be a unique design. The fact that it resembles his own prior work just proves that form follows function and horn math and theory didn't change in the short period between the design of those two subs.
If by reproduction you simply mean that they are both horns and that they have the same physical dimensions and snailshell fold, then this is valid. But I would consider a reproduction to be more like sticking different drivers in the same old horn - that's not what happened.
No arguments here, but none of that was what Danley was saying for years. It's even documented in video. Danley clearly said that for an equal volume and tuning, no other alignment could beat a tapped horn. He said it over and over, he said it on all the forums, he said it in the video, and he argued at length with people that this was a truth, and it's not.
Clearly tapped horns fill a niche. They are somewhat more efficient than ported, since they are invariably larger. They can also be made quite small, small enough that with a given Sd it would be tough to design a flh with similar low knee and decent response because the compression ratio can get out of hand and you need uncommon flare shapes. But at the Labhorn level (low knee, Sd, cab dimensions) things start to even out and tapped horn and flh are close to neck and neck in performance - each has pros and cons but neither is a clear winner across the board.
Sure, but the point is that if tapped horns truly did beat all other alignments Danley would have no use for flh designs. Period. Full stop.
Anyone with a working copy of Hornresp or Akabak and a picture of a cab and a reasonable idea of what driver was used can reverse engineer Danley's designs. His design routine is pretty static - just by looking at his designs it's clear that he likes horns and he likes hyp/ex flares with low T, he likes to keep compression ratio at around 2:1 (with the notable exception of the TH118) and occasionally he likes to use stubs at the beginning of the flare in some of his tapped horns.
What else do you really need to know? What are these bread crumbs you speak of? I've never seen Danley say anything at all that would help anyone design a tapped horn.
As far as these "trade secrets" - if anyone isn't bright enough to figure out how Danley designs I guess they don't really need to know.
GM is (or at least used to be a few years ago) pretty infamous for saying "you aren't doing it right, I know how to do it but I'm not telling because Danley has two teenage girls to feed". When I reverse engineered GM's design routine (which incidentally is pretty close to how Danley designs) it turned out to be dead simple and common sense. I won't tell how he does it, as he clearly doesn't want anyone to know, but it isn't any kind of trade secret - it's just common sense good design. And you can get just as good results by playing with the sliders in Hornresp as long as you know what you are doing and realize what is required to design high performance systems.
This withholding of information out of a desire to protect "trade secrets" (in Danley's case) or out of respect for Danley (as is the case with several people on this forum) is not helping anyone, as far as I'm concerned.
Tapped horns are patented, so it's impossible to harm DSL by sharing "trade secrets". If the company has the wherewithal to defend their IP none of this matters - diy'ers are inconsequential to their company. And I've seen posts from the DSL camp aggressively indicating they do have lawyers ready and willing to fight.
Besides, Danley is just an employee, he's going to get paid regardless of what happens unless the company fails. So the only person that's really got something to lose is the bible thumping weirdo owner of the company.
Rant over, I guess. I just really dislike people withholding information for reasons that don't benefit anyone, it makes more work for me, as I am always going to find out the design "secrets" on my own anyway.
Bad design is bad design. He tried to stuff way more Sd in the cab than it could feasibly accommodate - that much is clear. But I haven't seen the internals so it's hard to say what else he might have done wrong.
Are you talking about Unity/Synergy horns or tapped horns here? Because most of the tapped horns DSL sells are way to small to have any significant pattern control in the passband.
I'm not sure which products they sell more of, but they sell a lot of little stuff. I was under the impression that their occasional "big" job was done more for the stature and marketing, not to keep the company afloat. The bread and butter is almost always the smaller item sales in large quantities.
I find it a lot easier to sim twice and build once. YMMV.
JAG,
I generally don't mind your rants
.1) The truck integers are divisions of what used to be a standard truck box width of 90 inches- 45, 30, 22.5, 15, and 11.25 inches.
2) Sticking different drivers in the same old horn is pretty much what happened, but required some minor changes since the LABhorn uses 12" and the BT7 15". By the way, I have replaced SDL drivers with standard drivers, the cabinets worked fine, no more call backs from the disco.
3) In the case of the Keystone, 6 dB more efficient than ported with an increase of only about 35% volume,
4) Obviously, since DSL produces BR, TH, BH, and FLH, Tom uses what is appropriate for the desired application or target audience.
5) I don't think I saved all the "bread crumbs" Tom has left behind over the past 26 years or so that I have followed his work.
6) Right.
7) I don't recall the patent being effective in keeping other companies from doing anything but direct copies, but I don't follow law suits.
8) Tom certainly has a vested interest in the company, and as well as the "bible thumping weirdo owner", there are a number of other employees directly affected by DSL's market share.
9) Yes, the large Synergy designs with Biblical names, other than the BH series none of the DSL LF designs have much more pattern control than BR cabinets.
10) My impression is the opposite, the big installations which use a spread of cabinets from the entire product line are the bread and butter, relatively small sales volume from touring or club sales, as is obvious by how few of their product you see anywhere but HOW and sports stadiums.
11) I don't find sims all that easy, but I usually do a lot more than two iterations, then several adjustments to the cabinets after the initial build.
Art
I realize that's how it ended up, I'm just saying this is different than a kid that forgets to do his homework so he hands in a paper from the previous year. The math and physics and practical considerations made them end up very similar but he did do the design work for the unique project that is the Labhorn. And it was very competently done, except for the botched folding producing rear chambers much smaller than the design called for.
Yes, and while efficiency is cool and all (I am a huge fan) it isn't the end of the story. The 35 percent larger tapped horn uses considerably more excursion for the same power input - therefore if excursion is a limiting factor for the tapped horn, the 35 percent smaller ported box can take more power than the tapped horn and the max spl results won't be much different, assuming power and port compression are not an issue for the smaller ported box.
Here's a quick 5 minute example, I chose a random TH from my records (I don't even know whose design this is, but it has a clearly defined low knee which is important for this) and then took the same driver and put it in a ported box that turned out 1/3 the size of the tapped horn. The TH takes 32V to reach xmax, the ported box takes 38. Assuming power and port compression are not an issue for the ported box, what do you get from the 2/3 larger tapped horn? A couple of db at the low knee, which is the only place it really matters. The tapped horn is clearly more efficient but it doesn't matter much at the excursion limits.
An externally hosted image should be here but it was not working when we last tested it.
I admit the port should have been a bit larger in this sim but I didn't want to take too much time on this - velocity peaked at 27 m/s, it wouldn't take more than a few liters of extra port to bring that right down to acceptable levels.
Regardless of whether the general public is bright enough to figure out Danley's designs I'm not too concerned what is considered trade secrets or not - if I went to the trouble to find stuff out I'm going to discuss it. How far would discussions like this get if we didn't talk about anything because somebody makes a living off of it? We all learn from each other, otherwise what's the point? (Oops, am I ranting again? I guess this is a sore spot for me, for good reason.)
I never do anything twice (not loudspeaker builds anyway, unless it's a stereo pair). I'm lucky enough to get my lazy butt up for long enough to build it once, and I definitely don't enjoy the construction process. My finished projects have always performed as the sims indicated they would so I've never needed to iterate physical projects (although I've not always made the best design decisions - but that's not the fault of the simulator), all the design work gets done on the computer.
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In other words, the TH would require less power to achieve a similar or greater SPL level than the vented box.
That's a hell of a big assumption. Real-world vented boxes suffer from those two effects significantly more than THs. And once you start trying to make that vent large enough to reduce the impact of port compression effects on that vented box to as low as that experienced with the TH, that size difference diminishes significantly.
That's 128W vs 180W into an 8 ohm load.
Given a 4 ohm load, that's 256W vs 361W
To achieve the same SPL, the vented box will run hotter, and because THs are usually better ventilated (a by-product of their implementation), the heat buildup will also be faster in a vented box. If you're running them to the max, the vented box will start suffering from performance-robbing power compression effects long before the TH. The proof of the pudding is really in the eating here - there have been many times I've run my POC3 TH at pretty good volume for get-togethers and the driver's magnet was only slightly warm by the end of the night.
Having built both, I probably won't do a vented box again, unless space constraints are an issue. It's THs or offset TLs for me.
JAG,
1) In the case of the B&C18SW115-4 loaded Keystone Sub, the excursion of the TH is less than the BR with the same driver and low corner for a given voltage at most frequencies. Distortion is higher for a given excursion in the TH, but a bit less for a given SPL.
2) Power compression was not an issue for either the BR or TH, the BR had it's speaker mounted vent out both for cooling and to maximize the internal volume of the test box used, a very solid box using 1" MDF with extensive bracing. Port compression was an issue on the ported box. As well as the Keystone being on average 6 dB more sensitive, it had no LF compression at full power/Xmax, while the ported box had a few dB LF compression, in spite of a rather large port with an extended interior "top hat" made from a 15" speaker cut out. Of interest, the BR had no compression in the upper range of the pass-band at full rated power, but the Keystone does show a bit in the sine wave testing. At clip, neither cabinet showed any compression using pink noise IIRC.
The OP in the Keystone thread details where to find the data supporting the observations above.
Art
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Brian, all of that is true. But assuming size is the limiting factor and max spl is the main goal, 3 of those simulated ported boxes would beat the tapped horn and take up almost exactly the same cab volume (especially if you put 3 drivers in 1 box). Even with a bit of power and port compression thrown into the mix for the 3x ported box, it still wins.
This requires 3x more drivers and more than 3x the amp power of course.
There are pros and cons to each approach.
This requires 3x more drivers and more than 3x the amp power of course.
There are pros and cons to each approach.
The only frequency that matters is the frequency where max excursion occurs inside the passband, that's your limiting excursion frequency. And the tapped horn will always have more excursion for a given power level if it's bigger than a ported box and has the same low knee.
With respect to all the rest, at some point I'll dig up the Keystone Hornresp inputs and do the same type of comparison with an equal size ported box. I've already done this in the past but I can't find my Keystone sim. As in the past, the results will be the same - just like the sims I just did, given an equal amount of space the ported box will win, even with some hefty power compression factored in. It takes more drivers and more amps to get there - more than double the cost - but the ported boxes will win.
I can design some very small flared ports that will have little or no port compression but we can even throw a fixed assumption power compression loss into the mix anyway and the ported box will still win.
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I thought that a bit curious when I first heard that. I didn't notice a similar compression at upper frequencies in the passband for my POC3 or the POC4 (though testing with the latter was VERY limited, and I was driving both at lower (in the POC3 considerably lower
) power levels. FR graphs at different power levels were essentially identical. Could it be possible that you were running into the limits of your recording equipment at higher frequencies? the Keystone does seem to be a bit more sensitive near the top of its passband, and the baffle step likely helps as well.The horns must hold up to wind, snow, rain, lots of vibration, and the occasional earthquake. I want the horns to last for at least 20 years. Reinforced concrete is the best material. With adequate rebar placement, the horn will hold its shape, and take years of abuse, with very little maintenance. As far as being a waste - if the horns sound great and last for 20 years, then the time & money were well spent.
I haven’t really talked about the midhorns. I plan on building a few different prototypes – to see what sounds best. These forums (and the internet in general) have a wealth of information on how to build good midrange horns - with dozens of real-world examples. Full size bass horns however – not so much. . . .
I would never run aluminum wire for anything audio. But copper welding leads however – don’t knock it until you try it. Copper welding leads are big bundles of very thin wire strands – similar to quality audio cable. The fine wire practically eliminates the skin-effect in the upper audio spectrum. Running 4/0 was an extreme example, however 4 gauge copper welding leads are almost superconductors compared to 14 gauge speaker wire - and a spool is not as expensive as one might think. . .
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