When reading about transmission line or back horn type designs the literature says they're very complex designs but then I read on forums people using designs like the frugal horn and people swapping and changing different drivers into the cabinets which to me seems like they're not so finely tuned to a driver and complex as I thought. What am I missing?
Nothing as such. It mostly depends on the design. The FH series I / we deliberately designed from the outset to have some flexibility / leeway in terms of driver characteristics. That's 'within reason' -it's not wide open, and of course it can't do much about the behaviour above the mass corner so like any LF load we can only affect that end of the spectrum to any significant extent.* But there's some room available for variations, accepting that the details of the alignment will change a little in the process. Other designs which are designed to be more tightly locked to a given drive unit have much less in the way of flexibility.
*there are exceptions like reactance-annulled LF horns, but you can count the number of those from the last 9 decades on the fingers of one hand.
*there are exceptions like reactance-annulled LF horns, but you can count the number of those from the last 9 decades on the fingers of one hand.
I suspect you're looking at the page for 3/4in, or other Imperial sheet material thickness. There are separate pages for the metric plans. Dave's Vectorworks software automatically adds an exact metric conversion when Imperial dimensions are used, which sometimes causes confusion as it's usually completely impractical and the equivalent metric / Imperial plans (depending on which measurement system was used as the original design base -for e.g., I tend to think in Imperial so that's the basis of many of my designs) are then rationalised & mildly revised as required in independent drawings. Personally, I prefer to only show values in a single measurement system on individual drawings, but I gather that generation of Vectorworks has a few idiosyncracies on those lines.
Scott, the metric plans are very helpful for people who doesn't handle the imperial system on a daily basis. Please keep it! 🙂
Don't worry, nobody's getting rid of anything. As I said, there are separate pages in the pdf files for the Imperial and metric plans. Personally, I'd be happier if the individual Imperial plans simply showed the relevant Imperial, and the individual metric plans simply showed the relevant metric, which would avoid confusion, but Dave's generation of Vectorworks doesn't usually allow that & automatically adds a sometimes rather useless conversion value for the other system in the same drawing.
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Lots of people do. The frugel-horns are not modelled in it -as I've said elsewhere before, nothing at all against it and I sometimes use it myself, but since they are not purely based around the 1d wave equation & other input limits, Hornresp isn't able to cover everything. Per my previous post, they're done in a combination of MathCAD, Akabak / ABEC, Ansys (Comsol in one case), and an early basis in Ron's own industrial wave-modelling software, which I later substituted the FEM & my own parabolic software for.
Yeah, over time HR has become quite powerful, but miss using MJK's for some things.
I hope not 😉 -he's a person, not a company or product. Martin created a number of worksheets for [then] Mathsoft's MathCAD mathematics software, but largely discontinued them for various reasons, including (if fallible memory serves) a major software revision which would have required a total rewrite. Since Hornresp & a couple of other packages were rapidly gaining new capabilities around that time, & it's a fairly specialist interest field anyway, those who hadn't already adopted them mostly did so -there aren't many things they can't handle.
Typically i push dimensions to the nearest mm. But in the case of somr designs, a piece is not quite thagt and i will show the tenth so that the builkder knows that his 788mm pirce might need a tiny bit of sanding to fit well.
There are few loudspeakers that are as versatile as the Frugel-Horns. TABAQ is another that seems fairly flexible. Quarte-wave designs where the box dominants end to ne most flexible, things like my miniOnkens are not versatile at all. Each driver needs its own tuning.
dave
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Yes, a bit of a pain, it is easiest to maintain separate files for metric and imperial set to single dimensions, and i have to adjust the 2nd drawing, ie not quite having to draw it twice, but an additional drawing. Given how far behind i am at keeping up with Scott’s very prolific output, i just cn’t get ton the second drawing. A few do, but most are drawn to the nearest mm and the imperial is the closest 1/32”.
I am currently going thru this process with a new widish compact bipole/monopole ML-TL for A11ms.
dave
Of course not -you've seen enough of my posts when I'm talking about test builds, test baffles, test pipes &c. 😉 And there's the old nine-key and ninety years of research, alignments, formulas and data to use. Software is a tool that helps shorten some processes, reduce the amount of work you need to do with the old precision mechanical instruments (saw & hammer...) and refine things. It's a very powerful tool, but it's a tool, no more.
As they say -ars longa, vita brevis. 😉
Dave can't do everything or he'd never get away from his computer -especially since it needs fighting some weird Vectorworks configurations too. Better in some cases to leave well alone with the 'near as' than watch the tide come over your (his!) head! Besides, most of our major designs have the independent drawings for different sheet materials in place -it's usually the 'smaller' releases where we have to keep things a bit more limited. It probably helps the old sanity too.
They are a very specific alignement that uses long, hgh aspect ratio, high resistance vents to push the design towards aperiodic.
Characteristics are that they are tend to have very articulate/elegant bass but they don’t push the extention only going as low as they go. They also tend towards the smallish size for a reflex.
dave
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