Has anyone ever simmed a Lowther Bipole ?
In particular, can a 'cheaper' driver of similar parameters (Fe206/7 say) be used on the back, with or without whizzer-ectomy?
I have DX2 in modded MJK-Voigt style cabs, but would be interested in getting rid of BSC and upping efficiency as amp is only 5 W max, and I do like loud, unclipped, music. And, my woodworking skills are very limited, so I don't think I'll be making horns in the near future.
Thanks.
In particular, can a 'cheaper' driver of similar parameters (Fe206/7 say) be used on the back, with or without whizzer-ectomy?
I have DX2 in modded MJK-Voigt style cabs, but would be interested in getting rid of BSC and upping efficiency as amp is only 5 W max, and I do like loud, unclipped, music. And, my woodworking skills are very limited, so I don't think I'll be making horns in the near future.
Thanks.
Brit,
Before you cut away at your Lowthers, there is another way to gain uncompressed head room and extraordinary clarity. Look at this thread starting about page 13 Post #128
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399&perpage=10&pagenumber=13
Then look here, in post #4 & #9 for pictures of what Ultrakaz did to his Fostex drivers and read his results, treating his set of Fostex drivers, in Post #16, of the thread.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100391&perpage=10&pagenumber=1
I will be actually treating the Lowthers shown in the pics in the EnABL thread. You might want to read the whole thing, it is a compilation of three separate threads.
Bud
Before you cut away at your Lowthers, there is another way to gain uncompressed head room and extraordinary clarity. Look at this thread starting about page 13 Post #128
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399&perpage=10&pagenumber=13
Then look here, in post #4 & #9 for pictures of what Ultrakaz did to his Fostex drivers and read his results, treating his set of Fostex drivers, in Post #16, of the thread.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100391&perpage=10&pagenumber=1
I will be actually treating the Lowthers shown in the pics in the EnABL thread. You might want to read the whole thing, it is a compilation of three separate threads.
Bud
That seems like a very definitive statement. So your conclusion is that under all conditions if you do not have a Lowther mated with a horn it is absolutely not going to work well. I can not agree with that statement.
If you analyze your SAXOPHON speaker, I bet you will find it acts more like a TL then a horn at ow frequencies. Or if you simply measure the electrical impedance, it will more then likely have multiple and predictable peaks indicative of a number of axial standing waves just like a TL. If I am correct, I am not sure I would classify your design as a horn over the low frequency range.
To address the original question. I have simmed a Lowther bipole and if I am not mistaken the default set up in my MathCad worksheet is a pair of DX2 drivers in a dipole configuration. It was a quick sim so I did not optimize the design or look at other driver possibilities. You can look at a pdf of the results on the Upgraded Models page on my site.
Hello britbug,
take it invers than you won´t get HF,
but you can win a better K2.
Hello MJK,
if you look the single simulations you are right,
but membran movement cross setting makes it like that,
look the data:
http://www.hm-moreart.de/86.htm
look a Lowther measurement group by AER:
phase plug yes /no
http://www.aer-original.com/html/hobby_hifi_01_jan_2002.html
take it invers than you won´t get HF,
but you can win a better K2.
Hello MJK,
if you look the single simulations you are right,
but membran movement cross setting makes it like that,
look the data:
http://www.hm-moreart.de/86.htm
look a Lowther measurement group by AER:
phase plug yes /no
http://www.aer-original.com/html/hobby_hifi_01_jan_2002.html
I have to say I'm with Martin and GM on this. Lowthers do not require a horn as a given in order to sound good. They work perfectly well in other enclosures, or run OB, particularly with decent LF support from additional woofers.
Wouldn't Saxophon just make for a combined system of two differentially tuned expanding QWRs with an additional waveguide loading the other side of one driver? Don't get me wrong, I'm not knocking it, I think the design's very creative. But a genuine horn is about the size of the average garage, and anything less is still a hybrid QWR / horn.
Wouldn't Saxophon just make for a combined system of two differentially tuned expanding QWRs with an additional waveguide loading the other side of one driver? Don't get me wrong, I'm not knocking it, I think the design's very creative. But a genuine horn is about the size of the average garage, and anything less is still a hybrid QWR / horn.
Hello Scottmoose,
if you look the single simulations,
you will see no bass below ~70 Hz !!
and a rise at 150-200 Hz of ten dB,
worse as can be, but you see the measurement,
I am most astonished.
The amp "see" only one horn imp.
movement cross setting makes one oktave
deeper than expected, mouth distance
cancle the rising.
look the free plan TROMBONE, two driver with 120 Hz reso
going down to 38 Hz !!
Test it for lowest costs than you might believe me.
if you look the single simulations,
you will see no bass below ~70 Hz !!
and a rise at 150-200 Hz of ten dB,
worse as can be, but you see the measurement,
I am most astonished.
The amp "see" only one horn imp.
movement cross setting makes one oktave
deeper than expected, mouth distance
cancle the rising.
look the free plan TROMBONE, two driver with 120 Hz reso
going down to 38 Hz !!
Test it for lowest costs than you might believe me.
Can't say I'm particularly astonished. You've got in Trombone & Saxophon two differentially tuned expanding QWRs, one balancing out the response of the other. There aren't many designs of that type around currently, probably because of the additional complexity involved, but the idea's been mooted in the past -Voigt patented a version in his 1934 application for example. It's a good idea IMO if the aforementioned additional complexity is accepted.
However, we're getting a bit off-topic.
Britbug, yes: you could use an FE206E or similar on the back of an MLTL witht he Lowther front-mounted easily enough. Brace the magnets together and you'll get even more benefit as it'll dramatically reduce panel vibration.
However, we're getting a bit off-topic.
Britbug, yes: you could use an FE206E or similar on the back of an MLTL witht he Lowther front-mounted easily enough. Brace the magnets together and you'll get even more benefit as it'll dramatically reduce panel vibration.
I beg to differ. As you know, to use the exponential flare as an example, a genuine horn's cross sectional area formula should be definded by S(x)=So e^(m x).
If you prefer, one could also describe this as flare being proportional to throat CSA * e^4*pi*X inches / lambda. Path length should be a minimum of 1/4 wavelength of Fc, preferably 1/2 wave or more, with a mouth circumference ideally = wavelength of Fc (assuming free-space). That's a real horn. I don't think your cabinets, good though they likely are, quite qualify, even factoring half, quarter or corner-space into the equation. Not many do, with the exception of some move-theatre horns, and Nelson Pass's Kleinhorns as mouth CSAs of, say, 200 ft^2 (each) are not very practical for most living rooms.
Everything else is a hybrid, using some form of QW loading at the low end and shifting to horn loading higher up as the impedence-matching improves.
Lowther have never built a cabinet exactly like yours AFAIK -I don't remember anyone suggesting they have. Their twin driver pseudo horn cabinet (the Academy, I believe you're refering to?) isn't up to much IMO.
Using differential tuning of QW tubes, which is what you've effectively got a version of here, using two separate tubes & drivers to create a summed system, is hardly a new idea though. Figures 6 & 7 in the attached show just two examples of this, using only one driver, taken from Voigt's 1934 patent application. There have been plenty of others, using single or multiple drivers since then. One place where the idea of differential pipe-tuning was very heavily discussed was the old Full Range Forum -run a search.
Another place where differential tuning is mentioned: http://yu-ra.tripod.com/tqwta.htm -again, can be one driver exciting different lines, or multiple divers exciting their own lines, to form a combined system.
It was even mentioned in a TNT Audio review of Bert Doppenberg's TQWT: http://www.tnt-audio.com/casse/tqwp_e.html -look at the bottom. There really is almost nothing new under the sun, and this is a very old idea. Yours looks like a good implementation.
Best
Scott
If you prefer, one could also describe this as flare being proportional to throat CSA * e^4*pi*X inches / lambda. Path length should be a minimum of 1/4 wavelength of Fc, preferably 1/2 wave or more, with a mouth circumference ideally = wavelength of Fc (assuming free-space). That's a real horn. I don't think your cabinets, good though they likely are, quite qualify, even factoring half, quarter or corner-space into the equation. Not many do, with the exception of some move-theatre horns, and Nelson Pass's Kleinhorns as mouth CSAs of, say, 200 ft^2 (each) are not very practical for most living rooms.
Everything else is a hybrid, using some form of QW loading at the low end and shifting to horn loading higher up as the impedence-matching improves.
Lowther have never built a cabinet exactly like yours AFAIK -I don't remember anyone suggesting they have. Their twin driver pseudo horn cabinet (the Academy, I believe you're refering to?) isn't up to much IMO.
Using differential tuning of QW tubes, which is what you've effectively got a version of here, using two separate tubes & drivers to create a summed system, is hardly a new idea though. Figures 6 & 7 in the attached show just two examples of this, using only one driver, taken from Voigt's 1934 patent application. There have been plenty of others, using single or multiple drivers since then. One place where the idea of differential pipe-tuning was very heavily discussed was the old Full Range Forum -run a search.
Another place where differential tuning is mentioned: http://yu-ra.tripod.com/tqwta.htm -again, can be one driver exciting different lines, or multiple divers exciting their own lines, to form a combined system.
It was even mentioned in a TNT Audio review of Bert Doppenberg's TQWT: http://www.tnt-audio.com/casse/tqwp_e.html -look at the bottom. There really is almost nothing new under the sun, and this is a very old idea. Yours looks like a good implementation.
Best
Scott
Attachments
Hello,
what would you tell us,
your explanation has nothing to do with my
solutions, if you don´t know how the academy
works don´t compair it.
You describe physics optimum, for a new Woodstock concert
needed but not for living rooms,
the length and the funnel constante is more important than
the horn mouth.
You don´t understand my construction,
that´s all i can read, sorry.
If you need a 3 or 4 explanation of the Saxophon,
I will repeat it again for you.
what would you tell us,
your explanation has nothing to do with my
solutions, if you don´t know how the academy
works don´t compair it.
You describe physics optimum, for a new Woodstock concert
needed but not for living rooms,
the length and the funnel constante is more important than
the horn mouth.
You don´t understand my construction,
that´s all i can read, sorry.
If you need a 3 or 4 explanation of the Saxophon,
I will repeat it again for you.
I understand how the Academy works. Please tell me where I compared it to your speakers? Because you'll find that I didn't. They have nothing to do with each other, aside from the fact that both use two drivers. I went out of my way to stress that: you obviously missed the bit where I said 'Lowther have never built a cabinet exactly like yours.'
I understand the basic idea behind your solutions / construction (which are not actually new, given that variations on these themes have been around for over 70 years), so you don't need to explain it. What I'm pointing out is that by any physics I know of, they are not horns. That's all. You're the one who claimed they were, and all I did was illustrate that they in fact are not, as they do not meet the necessary criteria to be so classified. They're simply not big enough. If either line uses QW action (and they clearly do), then it's a hybrid. Summing the responses of the two separate lines doesn't change that. Nothing wrong with this approach (quite the oppositite) & no-one's suggesting there is, but by definition, it's not the same thing.
I understand the basic idea
understand the basic idea behind your solutions / construction (which are not actually new, given that variations on these themes have been around for over 70 years), so you don't need to explain it. What I'm pointing out is that by any physics I know of, they are not horns
Very true, even my designs are based on concepts that have been around a long time, and i knew Moby Dick when he was a minnow. All i ever did was to refine the applications. Without running any sims it appears to be primarly a dual TL action. To achieve true horn action to even 50 Hz requires a very very large mouth.
Every day i try to defeat physics, i can bend them, i can fool them but in the end i havent ever beat them.
ron
Very true, even my designs are based on concepts that have been around a long time, and i knew Moby Dick when he was a minnow. All i ever did was to refine the applications. Without running any sims it appears to be primarly a dual TL action. To achieve true horn action to even 50 Hz requires a very very large mouth.
Every day i try to defeat physics, i can bend them, i can fool them but in the end i havent ever beat them.
ron
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