I have posted my Bailey line impedance and response curves earlier. May I see the result of your Martin King box that also have a single peak impedance, go down to 30 Hz at 6 dB/octave? 😉
Below are some other examples of the Bailey lines. The first figure is Bailey's and the second picture are published by Gary A.Galo in Speaker Builder.
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Nope. Too hard to find a good onefrom the 100s of sims scatteredall over my HD.
We mostly use aperiodic lines for mid tweeters.
dave
We mostly use aperiodic lines for mid tweeters.
dave
You are right. You see that my measurement stopped at 50 Hz because the reading below that were unreliable. I could hear the Bailey TL go much lower than that and estimate the -6 dB point to be around 30 Hz.
I did the response measurement using near field mikes at a large size empty lab, but not an anechic chamber. It was a poor man's version of D.B. Keele's nearfield technique. I was able to do it when I was a graduate student.
I recently bought a calibrated USB microphone and the TrueRTA software from Parts Express. Not sure what I can do in a 15'x25' basement yet. May have to go outdoor.
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Then you don't know at what rate the ultimate toll-off was? You'd need to be down to 10 Hz or so to get any real idea.
dave
Dave,
To be honest with you, I don't believe what you said about the Martin King TL-Modeler is mathematically nor physically possible. Martin King did not properly account for the reactive component of the impedance added by the fiber material. A resistive fiber model may give reasonable curve for polyester filler in a vented resonance tube, but it is completely useless in modeling the long fiber wool filled Bailey tube. The complex number model that Bradbury developed is a minimum requirement for this type of modeling. Ken Kantor, in his blog, show a scientific paper (Specific Acoustic Impedance: A Derivation) by John F. O'Hanlon that showed similar complex number approach worked well for fiber glass filled closed box enclsoure too. They cannot be all wrong!
"Show me" if you want to prove me wrong. I am from Missouri. 🙂
Agree partially. That's why I showed the measurements from Arthur Bailey and Gary Galo.
But the listening effect of a Bailey slow decay TL vs. a fast roll-off vented box is easy to distinguish.
I understand what gpapag is talking about when he said "The bass is tight with weight, very good control". Martin King showed that he could damp out the excessive bass ringing by very heavy stuffing of Dracon. But it hardly has any bass response left when he did that.
The Falcon Acoustics 5aB crossover kit is a good substitute for the Radford crossover if the same KEF drivers are used.
KEF CONCERTO UPGRADE CROSSOVER No.5aB MF and HF Recommended Upgrade
Hi,
I fed up with this self justify denial of reality.
You can find details of stuffed lines on MJK site than completely
suppress the lower impedance peak and the resultant response.
(And various levels of damping of the upper peak too.)
Saying he has never done it is just wrong, and self justifying.
You tell me what is wrong with his maths, and don't say it
is just wrong because you say so, and old school is right.
That is head in the sand stuff, and not trying to understand.
For MJK results pretty much follow predictions, and using
MJK's analysis shows most old school TL's do not follow
the claimed performance and are not really optimised,
e.g. a large chamber behind the driver does not low pass.
What is the best impedance profile and resultant response
is open to debate and for suitable purpose, not pure dogma.
What is the point of ignoring what you can learn with current tools ?
Its just pure pontification on your part the old school stuff is right,
when a lot of it is simply handwaving and not rigorously analysed.
rgds, sreten.
I fed up with this self justify denial of reality.
You can find details of stuffed lines on MJK site than completely
suppress the lower impedance peak and the resultant response.
(And various levels of damping of the upper peak too.)
Saying he has never done it is just wrong, and self justifying.
You tell me what is wrong with his maths, and don't say it
is just wrong because you say so, and old school is right.
That is head in the sand stuff, and not trying to understand.
For MJK results pretty much follow predictions, and using
MJK's analysis shows most old school TL's do not follow
the claimed performance and are not really optimised,
e.g. a large chamber behind the driver does not low pass.
What is the best impedance profile and resultant response
is open to debate and for suitable purpose, not pure dogma.
What is the point of ignoring what you can learn with current tools ?
Its just pure pontification on your part the old school stuff is right,
when a lot of it is simply handwaving and not rigorously analysed.
rgds, sreten.
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Argue against all the impirical evidence of hundreds & hundreds of TL builds where MJK's model agreed with what was built.
dave
I too know about that. The reason i like TLs. King's software gives us a huge space to play in.
dave
Martin King never analyzed or tested a long fiber wool filled tube. If you can find it at his site, show me the link. You can read the details of my exchange with Martin directly at AudioKarma.
Transmision Line ? - AudioKarma.org Home Audio Stereo Discussion Forums
The problem in Martin King's model is that he does not properly account for the fiber effect. See my reply to Planet10 for more detail on this point. I already PM you the mistake he made reading the Bradbury paper. You obviously do not understand the point.
Martin King created a new enclosure using tapered resonance tube. Some like its sound. Nothing wrong with that. It is ridiculous to argue that he could model the Bailey TL when no one ever showed any analysis.
I always suspect that you do not read the posts of the thread before you write, either responding to you or to others by me.
One of many new tools that Martin's model brought to the table. His model showed us how little of TL "space" we were exploring.
dave
I have posted my Bailey line impedance and response curves earlier. I also show that from Bailey and Galo. And George also showed his using the Radford kit from Greece. May I see the result of a single Martin King box that also have a single peak impedance, go down to 30 Hz at 6 dB/octave? You must remember something among the "hundreds & hundreds" of Martin King boxes built.
"Argue against all the empirical evidence"? Sorry, I have not seen a single one yet and am waiting.
I never said that the Martin King TL-Modeler did not match his measured results. Nor that they do not sound good. I commented that they look like a resonance tube and very different from the Bailey transmission line results. Can we agree on this point?
I have seen lots of sims with a totally suppressed secondary peak, and there have been many posted -- i am not going to look for them for you. The 6dB/octave is a supposition on your part… you have admitted that you did not produce a real measurement for that.
BTW: what Geotge posted was for Bailey's triangular line…
The Radford S90 was the 1st TL i heard and left a lasting impression on me. The fellow that built many of the examples of these was one of my early gurus. He went on to do leading edge work on aperiodic enclosures having grooked the essense of the Bailey-style TL.
dave
So was mine, also the 1972 Bailey triangular line.
Another good thread on fiber stuffing material for speaker enclosures over at AudioKarma.
Best place for Polyfill? - AudioKarma.org Home Audio Stereo Discussion Forums
Even for the very simple case of a closed box enclosure, there is no fast answer because different made of polyester reacts with sound differently. Pete Basel made this summary in the last post at the AK thread.
Hi,
I see in your exchange with MJK you are are as mindnumbingly tedious
as you are being in this thread. No you don't have the keys to the
castle or understand things that others don't. MJK spelt it out
for you but you choose to disagree. Very tedious and very boring.
I suspect you haven't read your way through MJK's articles,
and FWIW whilst MJK is a model of clarity, you obfuscate
to meaningless details, like MJK has never tried LFW, so
he can't know anything about it, which is just so wrong.
Its clear you prefer mindnumbing repetition of the way
you see things than any sort of dialogue, very tedious
attitude in a forum, and understanding things in general.
Quite typically you can't describe what you disagree
with accurately and keep making tedious simple
assumptions about them, which is just boring.
Or accurately describe what you think is right.
rgds, sreten.
I am sorry if my posts are causing you headache. Using technical terms in mathematics, fluid dynamics and thermodynamics are unavoidable at times when discussing speaker building.
The solution for you is very simple. Just stop reading any post with my name on it.
Keilau, you must just speak your truth and ignore the rudeness. Anyone who spends a lot of time here must be some sort of social misfit in my opinion. 😀
But, TBH, I have yet to hear a transmission line that excites me. The IMF TLS-80 with a KEF B139 was one of the dullest speakers I have ever heard.
No dynamics or presence whatsoever. It always sounded like it was playing in the next room.
But, TBH, I have yet to hear a transmission line that excites me. The IMF TLS-80 with a KEF B139 was one of the dullest speakers I have ever heard.
No dynamics or presence whatsoever. It always sounded like it was playing in the next room.
