New thread split off from here http://www.diyaudio.com/forums/full-range/182145-bib-vs-ibib-3.html#post2452926 
Chokes, reflex tubes at the end of horns, just like you were talking about.
:-O
Chokes, reflex tubes at the end of horns, just like you were talking about.
Yeah, but that's quite a recent "invention" or development. The Metronomes taper for example is, I have a strong inkling, only really good for keeping standing waves/resonance from going, not for horn loading. The exact same thing can be done with just a fiber plug, like in the Altec Aquarius 5 or the EPI Microtowers.
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Er, I think you'll find that it's more than a 'recent "invention" or development.' Unless you call the 1940s -'50s recent in terms of home audio? I suspect the boxes GM refered to above were ones he built back in the 1960s. And Olson was employing a slightly different variation back in the late 1930s. There really was just about nothing the pioneers of audio didn't do or explore, digital-era developments in Eq, delay etc. aside.
The Metronomes are technically tapped, mass loaded horns. If a pipe has a degree of positive taper present, then by definition it possesses some 1/2 wave characteristics, ergo, it's a horn.
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are just a straight end-loaded TL. The modern ode to microTower, uses mass loading to get lower bass from the same height column.
dave
Hey, I didn't say anything about the idea being bad as such, I was implying the 1. The idea is far from commonly used, even though it was once used and has seen a recent resurgence. 2. So there must be some drawbacks. Free lunches are very scarce in audio.
Yeah by definition, but how about in reality? How much horn action is really going on inside the box? Some sure, but not anything near enough to account for the bass coming out.
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The EPIs use port loading too. Though more a cross between aperiodic and BR (basically just a round hole in the bottom with some fiber stuffing).
I owned a pair of the original EPI microTowers, built a set of clones in 1974 (which i still have), and have had at least a couple more thru here since. No ports in any of them. A base plate with as large a circular hole in at as possible, as much to ensure that the bat of fiberglass (the whole length of the line) didn't slip out.
dave
dave
No free lunches in audio, but it never did depart, it's always been lurking around in the background in one form or another. Things move in & out of popularity, but you will recall that until the 1970s, some degree of DIY was considered more the norm than otherwise in high-end audio (or at least a worthy equal). It dropped out of favour for a while, but thanks to the 'net, DIY is now seeing an upsurge in interest once again.
What exactly do you mean by the term 'horn action?'
The degree is immaterial. If a pipe expands toward the terminus, it possess some 1/2 wave characteristics & will therefore be longer for a given Fp than an untapered, or reverse taper horn.
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IIRC, the fibreglass wall damping in the original EPI microtower was held in place by several spring steel strips, and the hole in the bottom plate was as large as possible while still retaining room for the spring loaded wire terminals and provide some structural bracing for the open end.
At the most, acoustical "end load" would be that of 3/4" deep port only slightly less than pipe CSA - which is rather different from the mass load of the Planet 10 designs.
At the most, acoustical "end load" would be that of 3/4" deep port only slightly less than pipe CSA - which is rather different from the mass load of the Planet 10 designs.
But this concept never really caught on to the degree of other ideas. I guess for a reason.
You could put a speaker at the bottom of a bucket and call it a horn, but you will still get very little loading.
Didn't catch on compared to what? As far as I know, variations have been quite popular for decades.
Indeed you could, assuming the bucket was tapered.
Indeed you could, assuming the bucket was tapered.
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But not at all to the degree of regular horns with various flares or standard BR.
But not with any bass worth speaking of. The Metronome is simply not long enough.
I'm afraid this is taking up too much of what little time I have, so this is my last on the matter.
-Certainly not as much as BR cabinets, but then, BR boxes are the dominant type because they're cheap & simple to calculate & make, largely thanks to Small. Compared to more complex horns? Much of a muchness, possibly slightly ahead if you care to investigate.
-I thought you were talking about buckets. Staying with those, of course not. But the basic principle remains. A Hawker Hurricane doesn't have the performance of a an F-22 Raptor, but that doesn't mean it isn't an aeroplane. Lemon juice isn't particularly strong compared to hydrochloric acid, but it's still an acid. That is the point I'm making.
-Certainly not as much as BR cabinets, but then, BR boxes are the dominant type because they're cheap & simple to calculate & make, largely thanks to Small. Compared to more complex horns? Much of a muchness, possibly slightly ahead if you care to investigate.
-I thought you were talking about buckets. Staying with those, of course not. But the basic principle remains. A Hawker Hurricane doesn't have the performance of a an F-22 Raptor, but that doesn't mean it isn't an aeroplane. Lemon juice isn't particularly strong compared to hydrochloric acid, but it's still an acid. That is the point I'm making.
I guess I get the last say then. I don't have the time to post either. I do it out of a sense of duty and I'm also procrastinating. 😉
1: I have cared to investigate and I didn't find more than a handful of examples that could be classified as "line restrictions in horns & pipes". Whereas there are literally thousands if not millions of horn types to be readily found on the web.
2. My point was simply that the hornaction in cabinets such as the Metronome is negligible in the bass region. That's not to say that the taper is useless, it just doesn't do much of the loading. It's more a way to avoid standing waves.
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Many, if not most, of the BLH really being more akin to a TL than a "true horn"
It is all seamntics. The modelers that have become available in the last decade have opened up huge swaths of quarter-wave space for exploration. Where one historical :type" ends and another starts is a blurry line. Just sit back and enjoy the creation.
dave
Surely you are not saying that the difference between BR and horn loading is semantics? One is a wideband resonator the other an impedance converter. Huge difference.
The quarterwave thing is in its most simple incarnation "just" a theory to find the optimal place for the driver in a given (mostly longish) box.
And I know many horns work like TLs but only at lower volumes and for certain frequencies, all gradually. And that's not a bad thing it should be added.
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RCA held its patent through the '60s, using it in a couple of products for its 15" LC-1A 'full-range' driver, but by then the race was on for ever more powerful amps and driver power ratings to shrink box size, so fell by the wayside.
Not all that much unless tuned quite low as I've suggested for both a tweaking option and for some corner loading apps. Mostly, it's for 'pumping up' the mid-bass efficiency where small drivers have already run out of linear power handling.
GM
Guess my previous response would have been more appropriate here. WRT DIY, without a relatively easy way to design something other than a simple box, most folks won't take the time to do 'due diligence' researching the physics of the situation or do the amount of experimenting me and a relatively few others did to empirically arrive at a workable solution.
Factor in that there was a lot of misinformation being published long before the internet became widely available, the relatively few folks who did gamble the $$$/effort were often disappointed with the results, so got a bad enough reputation to strongly discourage folks from experimenting.
Having gone my way ~ in a vacuum and paying virtually no attention to mass marketing consumer offerings, I was oblivious to all this until I got on-line and joined the late basslist where misinformation was more the rule than the exception. The internet had already become a 'dumping ground' for every half baked idea ever published it seemed and the depressing part was that some of it was being peddled by well known pros, presumably to protect their hard won knowledge they used to put food on the table, etc..
Right, a driver in a bucket is a low gain horn over some portion of its BW, but between marketers and designers wanting to separate their products/inventions from the masses, it would just as likely be called a waveguide today.
GM
True, though misleading to my way of thinking since a BR assumes that its particle density is ~uniform which requires a cab with a ~uniform shape whereas a ML-TL or ML-horn must have a high enough aspect ratio for its 1/4 WL action to impact the vent's tuning, i.e. make it shorter than a BR's with the same net Vb, Fb.
Your 'simple incarnation' only applies in the region between these two where the BR is morphing into a usable 1/4 WL resonator.
??? Until a horn is a 1/2 WL long, it's a 1/4 WL resonator, so ignoring the effect the taper ratio has on its effective acoustic length, a horn must be twice as long as a TL for a given gain BW.
GM
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