Yes, I find myself aspiring to greater things, at least I don't have those smartphones "sprouting out the ear" listening to music...kinda thought we have long since graduated from pimple-faced 60s' teenagers with AM radios glued to the ear. 20-20Khtz, plus or minus 2.5 Db...anything less is well, less. You can listen to your music on something "less" if you like , bit I like to hear things in their entirety, nothing added, nothing missing.
---------------------------------------------------------------------------------------------------------------------------------------------------Rick...
---------------------------------------------------------------------------------------------------------------------------------------------------Rick...
Which in essence means you are announcing that everybody should adhere to your rather limited personal critiera (apparently 20Hz - 20KHz +/- 2.5dB at some unknown distance on some unspecified axis) without any consideration for anything else whatsoever. I'm not sure it will be universally admitted that is to be elevated to the status of 'blanket requirement'. 😉 Especially since you didn't even notice the difference between an IB driver measurement and a 1m axial in-room system response measurement.
All I'm trying to say, let's not "sugar coat" a lousy response by "smoothing"...Let's use the highest resolution possible & then we can resolve these large peaks & valleys with the tools at our disposal...be it room tuning, a plain 31 band EQ, or a more permanent notch & band approach. With the kaleidoscope of enclosure types, choose one that "fixes" the most glaring of shortcomings & go forward from there.
There are many people in the world with many different ideas.
My friend did a lot of corrections with Trinnov Audio ST2 HiFi.
He says that he has not corrected it now, because "In the end I have much to gain, but much more to lose."
What does the port output from a MLTL or a Pensil look like? Wide bandwidth supporting baffle-step like a TQWT/Voigt pipe or a sharp peak like a regular BR?
Writing from a [temporary] remote location due to a minor problem with both my heart and liver going a bit haywire, but short version is 'it depends on the alignment'. The longer version goes something like 'it depends on the alignment, and also the comparitive basis, but within those major caveats usually somewhere in between.'
Remember, a bass reflex or other form of Helmholtz-based vented box doesn't necessarily have a sharp peak at tuning -that also depends on the alignment [another caveat] & is something I always try to avoid if possible. And an ML-Voigt doesn't necessarily provide a 'wide bandwidth supporting baffle-step' either [next caveat]. It's usually a bit wider than a direct equivalent [and another] untapered QW or Helmholtz vented, but in most cases they're still standing-wave generators, with little or no horn loading in their functional BW, so unless they're getting help from the driver's natural response & the baseline alignment, it's usually insufficient to provide full compensation. With those exceptions [I suppose that makes for another of them hevil caveats 😉 ], you generally need a 'proper' horn or something approaching to do that with most 'modern' relatively narrow baffle designs.
Remember, a bass reflex or other form of Helmholtz-based vented box doesn't necessarily have a sharp peak at tuning -that also depends on the alignment [another caveat] & is something I always try to avoid if possible. And an ML-Voigt doesn't necessarily provide a 'wide bandwidth supporting baffle-step' either [next caveat]. It's usually a bit wider than a direct equivalent [and another] untapered QW or Helmholtz vented, but in most cases they're still standing-wave generators, with little or no horn loading in their functional BW, so unless they're getting help from the driver's natural response & the baseline alignment, it's usually insufficient to provide full compensation. With those exceptions [I suppose that makes for another of them hevil caveats 😉 ], you generally need a 'proper' horn or something approaching to do that with most 'modern' relatively narrow baffle designs.
@nandappe can the duct on the DDVP-12.5-ML ble changed to a round port? Converted to the same port area/size ofc. That would allow me to experiment with different tunings 😃
It seems like a good idea to block the front duct and attach a round duct or a variable duct to the rear.
Could one achieve the same thing by having an open bottom and use adjustable feet/spikes to tune the port? Kind of like what Troels Gravesen did:
My friend uses DIY-Loudspeaker's SBA-761, but he says it is troublesome to adjust the height of the aperture.
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…in most cases they're still standing-wave generators, with little or no horn loading in their functional BW, so unless they're getting help from the driver's natural response & the baseline alignment, it's usually insufficient to provide full compensation. With those exceptions [I suppose that makes for another of them hevil caveats 😉 ], you generally need a 'proper' horn or something approaching to do that with most 'modern' relatively narrow baffle designs.
From my limited understanding, a Voigt pipe/TQWT is a transmission line on one end and a conical horn on the other no? And if a damp duct is employed, it functions as a low pass and helmholtz resonator?
No: it's just a tapped conical (or parabolic if it has any parallel sides) horn that in the majority of cases is not impedance matched over its operating BW, hence the fact that it's just a standing-wave generator. It doesn't have a separate horn on one end & TL on the other -both terms ('horn' & 'TL') are basically the same thing as far as physics go, they're just typically used differently.
A 'damp duct' is just what everybody else has called 'mass loading' for decades now, in reference to the air mass in a vent. It functions in basically the same way as a duct in any other form of vented enclosure. A duct itself is not a Helmholtz resonator as such BTW -that's 'just' anoher term for cavity resonance. It does have an acoustic low pass effect though.
A 'damp duct' is just what everybody else has called 'mass loading' for decades now, in reference to the air mass in a vent. It functions in basically the same way as a duct in any other form of vented enclosure. A duct itself is not a Helmholtz resonator as such BTW -that's 'just' anoher term for cavity resonance. It does have an acoustic low pass effect though.
Maybe in the sense that the term transmission line is often used as a gerneral term to descibe any half or quarter-wave line.
The damp-duct more usually called a restricted terminus or mass-loading. It does function as a low-pass.
dave
The damp-duct more usually called a restricted terminus or mass-loading. It does function as a low-pass.
dave
Thanks for the explanations! I'm leaning towards @nandappe 's DDVP-12.5-ML with an open bottom. Unless there is a reason this won't work as well as the original port? I'll construct a simple method for adjusting height and thus tuning 😀
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Threw together an open end DDVP-12.5-ML test enclosure using the floor as a damp duct with a small 0,5 cm opening and a large 7,5 cm. Pretty good results I'd say! The smaller opening boosts the low end by quite a lot far field (not much difference at 1 meter).
Measurements are ducts, near field (1 meter) and far field respectively. No gate.
Measurements are ducts, near field (1 meter) and far field respectively. No gate.
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