Hey guys,
I was curious as to what the pros and cons were of esoteric subwoofer designs were, like tapped/folded horns/etc, as opposed to sealed and vented cabinets
Many thanks in advance. Much love
(Did some research on them, yet still came up confused, so some clear cut responses would be appreciated)
I was curious as to what the pros and cons were of esoteric subwoofer designs were, like tapped/folded horns/etc, as opposed to sealed and vented cabinets
Many thanks in advance. Much love
(Did some research on them, yet still came up confused, so some clear cut responses would be appreciated)
Sealed: small, doesn't care much about driver operating characteristics. Often low sensitivity at low frequencies, so lots of power is needed. Least excursion-limited output, since you're only using one side of the cone.
No specific tuning frequency, so can go very low if excursion and power is available.
Vented: more sensitive to shifts in driver characteristics. Bigger than sealed for a flat response, but lower cutoff. Should never be used below tuning. Since the vent contributes around the cutoff frequency, excursion is minimised around there, so maximum output is increased. Since it uses a Helmholtz resonator, group delay is higher than a sealed box (whether this is audible is debated occasionally).
Tapped Horn: usually twice the size of a vented box, but will put out ~6dB more across the same frequency range. Increased distortion when doing the extra SPL, though, since there's a lot of pressure acting on the cone. Quarter-wave resonator, so again, group delay isn't as good as that of a sealed box. Can't be used below tuning. Great when you have limited budget, but lots of space - you can get a lot of noise out of inexpensive drivers.
FLH: acts as an acoustic transformer, effectively making an acoustically small diaphragm drive an acoustically large bit of air, by controlling the expansion rate and length. Lots of pressure at the cone. A conventional FLH uses a sealed back chamber, so heatsinking can be an issue at high power.
A full-sized FLH is usually regarded as the ultimate low-frequency device. They can be huge, but offer lots of output and bandwidth.
HTH
Chris
No specific tuning frequency, so can go very low if excursion and power is available.
Vented: more sensitive to shifts in driver characteristics. Bigger than sealed for a flat response, but lower cutoff. Should never be used below tuning. Since the vent contributes around the cutoff frequency, excursion is minimised around there, so maximum output is increased. Since it uses a Helmholtz resonator, group delay is higher than a sealed box (whether this is audible is debated occasionally).
Tapped Horn: usually twice the size of a vented box, but will put out ~6dB more across the same frequency range. Increased distortion when doing the extra SPL, though, since there's a lot of pressure acting on the cone. Quarter-wave resonator, so again, group delay isn't as good as that of a sealed box. Can't be used below tuning. Great when you have limited budget, but lots of space - you can get a lot of noise out of inexpensive drivers.
FLH: acts as an acoustic transformer, effectively making an acoustically small diaphragm drive an acoustically large bit of air, by controlling the expansion rate and length. Lots of pressure at the cone. A conventional FLH uses a sealed back chamber, so heatsinking can be an issue at high power.
A full-sized FLH is usually regarded as the ultimate low-frequency device. They can be huge, but offer lots of output and bandwidth.
HTH
Chris
I've yet to hear a tapped horn in a well tuned rig situation, but with my experience in bass reflex designs and other designs vs FLH, FLH is more articulate with better transient response and separation between kick and basslines. I'm not sure I've heard a well tuned BR cab OTOH(especially not a DIY one) but my preference is FLH = King when it comes to EDM(In adequate size of the stack). Many here have much more knowledge on the subject than me but take it for what it's worth.
Tapped horns really shine when you need extreme output, like outdoors. In those cases there is no practical substitute for efficiency, and in that domain they are king of the hill. They can achieve output levels that nothing else can, short of perhaps a motor-drive sub or variable-pitch fan type.
I use the opposite, isobaric, which are very compact but low-efficiency. I use 21,600 watts to accomplish what Danley does with 800. I put the amps in another room so you don't hear two dozen fans. Now I don't live in the house I own, so I use headphones for the time being LOL.
I use the opposite, isobaric, which are very compact but low-efficiency. I use 21,600 watts to accomplish what Danley does with 800. I put the amps in another room so you don't hear two dozen fans. Now I don't live in the house I own, so I use headphones for the time being LOL.
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Interesting, what are the benefits of your rig? Low distortion/deep extension/good integration with tops? Makes me curious!
My rig is active 2-way on each side with wide-bandwidth sections that still overlap frequency coverage, and 16 to 32 12" speakers easily fit in the corners of a livingroom but are very heavy. A typical PA using tapped horns uses them for only the bottom octave, is enormous, cabinets are lighter, doesn't go as low, and uses stereo 5-way crossovers.
"Esoteric"? The is soooo Canadian polite!
This thread being a disorganized grab-bag of unrelated thoughts so far, here're mine.
1. Not correct to include folded horns in your question. A horn is the only feasible way (outside of electrostatic designs) to properly engineer a speaker so as to match a heavy piece of cardboard with thin air. Being folded is a minor concession to practicality. Still not feasible, but certainly not esoteric.
2. A tapped horn originated as a PA speaker which for some reason has been adopted here (and only here) as a quality speaker. Be careful not to criticize it on this forum.
3. In the "in the running" category and not "esoteric" are boxless or box-low mounting like leaky sealed boxes (which often are dipoles) and the tuned pipe system ("transmission line") which is cousin to the resonant box system.
4. Comparisons of resonant boxes and sealed boxes on this forum are mostly basic frequency responses presented in single-variable comparisons. More complicated than that.
5. That leaves a variety of truly esoteric and/or complex designs some of which just might have value like the mysterious Karlson, also taken to heart here and the 6.5-bandpass in deAppolito alignment.
Ben
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Excessive of me to say "only" but that's roughly my impression.
THs seem to have some sales in a few major big-size places, judging from the Danley website. To their credit as suitable PA speakers. So I'm not surprised to learn they are discussed at PA or music festival sites.
Can you provide links to places (other than those with commercial purposes) that promote THs as quality music speakers for homes?
Ben
Another thought. . .
Pretty much ANY speaker is a resonant system. It's how you use the resonance that makes the different alignments.
A sealed box is one kind of resonant system, and it really doesn't use the resonance to reinforce the response, hence the desire for "Q" of .707, which is "optimal damping".
A reflex box attempts to tune the resonance and use it to reinforce the deepest frequencies that the system produces. Unfortunately, that means some delay is required to get the resonance started
Tapped Horns are multi-resonant systems, with the delays implied.
Folded and not-folded horns can be non-resonant, and can provide quality response, but . . . they are inconveniently large, and often include resonances in the cabinet that color the sound.
Pretty much ANY speaker is a resonant system. It's how you use the resonance that makes the different alignments.
A sealed box is one kind of resonant system, and it really doesn't use the resonance to reinforce the response, hence the desire for "Q" of .707, which is "optimal damping".
A reflex box attempts to tune the resonance and use it to reinforce the deepest frequencies that the system produces. Unfortunately, that means some delay is required to get the resonance started
Tapped Horns are multi-resonant systems, with the delays implied.
Folded and not-folded horns can be non-resonant, and can provide quality response, but . . . they are inconveniently large, and often include resonances in the cabinet that color the sound.
I'd hardly call any of them "esoteric". They're all acoustic transforms of different types that have distinct effects on the system at whole. Some quench the back wave (sort of, it becomes an air spring) and work primarily with the front wave, some use both the front and back wave.
And, frankly, short of a sealed box, all require solid engineering to maximize the desired intent (Response, max SPL, group delay, sensitivity, $$, etc). The benefit is that many of the less intuitive designs are opened to us amateurs by the excellent work of several developers (such as David McBean with Hornresp), and users who have helped explain the compromises of different loadings. Hoffman's iron law still governs things.
Alignments, along with driver selection, are design parameters. They're a tool, a means to an end. Choose a goal and work with it.
E.g. I'm reworking a defunct Logitech Z680 system (got the sub+amps for free!), my goals are relatively flat response up to ~200 Hz (not ideal, but I've got to integrate with the satellites!), get an f3 lower than 40 Hz (so looking at around 2.5 octaves, within the reach of many horn/bandpass systems), with as much sensitivity as I can muster, given the wimpy built-in amp I'm working with.
I'm constrained by the driver and not wanting a box larger than about 2.5 cu ft. That said, I know that I won't drive the system any higher than 100 db (on transients, no less), so I went for extension over sensitivity (and overall output). For my design goals and constraints, an (OD)ML-TL alignment seems to be the best compromise. For a different set of goals, a FLH or TH might have worked better, or a quarter-wave alignment of sorts, or a sealed box for that matter.
An honest trip around something like the aforementioned Hornresp will tell you a lot more than this alignment is better than that.
And, frankly, short of a sealed box, all require solid engineering to maximize the desired intent (Response, max SPL, group delay, sensitivity, $$, etc). The benefit is that many of the less intuitive designs are opened to us amateurs by the excellent work of several developers (such as David McBean with Hornresp), and users who have helped explain the compromises of different loadings. Hoffman's iron law still governs things.
Alignments, along with driver selection, are design parameters. They're a tool, a means to an end. Choose a goal and work with it.
E.g. I'm reworking a defunct Logitech Z680 system (got the sub+amps for free!), my goals are relatively flat response up to ~200 Hz (not ideal, but I've got to integrate with the satellites!), get an f3 lower than 40 Hz (so looking at around 2.5 octaves, within the reach of many horn/bandpass systems), with as much sensitivity as I can muster, given the wimpy built-in amp I'm working with.
I'm constrained by the driver and not wanting a box larger than about 2.5 cu ft. That said, I know that I won't drive the system any higher than 100 db (on transients, no less), so I went for extension over sensitivity (and overall output). For my design goals and constraints, an (OD)ML-TL alignment seems to be the best compromise. For a different set of goals, a FLH or TH might have worked better, or a quarter-wave alignment of sorts, or a sealed box for that matter.
An honest trip around something like the aforementioned Hornresp will tell you a lot more than this alignment is better than that.
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