Line restrictions in horns & pipes

[Squeak]

New thread split off from here BiB Vs. iBiB

Originally Posted by Scottmoose

Use what?

:-O
Chokes, reflex tubes at the end of horns, just like you were talking about.

Originally Posted by Scottmoose

But you do. It's very common. What do you think the type of box that has become known as an ML-TQWT is? A mass loaded tapped horn, that's what.

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.

[Scottmoose]

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.

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.

[planet10]

Originally Posted by Squeak

EPI Microtowers.

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

[Squeak]

Originally Posted by Scottmoose

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.

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.

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.

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.

[Squeak]

Originally Posted by planet10

are just a straignt end-loaded TL. The modern ode to microTower, uses mass loading to get lower bass from the same height column.

dave

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).

[planet10]

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

[Scottmoose]

Originally Posted by Squeak

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.

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.

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.

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.

[chrisb]

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.

[Squeak]

Originally Posted by Scottmoose

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 this concept never really caught on to the degree of other ideas. I guess for a reason.

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.

You could put a speaker at the bottom of a bucket and call it a horn, but you will still get very little loading.

[Scottmoose]

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.