The mouth was approx 3ft across and the overall height was over 65"! And they were quite deep. I heard many variations of these and they were all very musical with (modified) Lowthers and the differences between models of drivers was much as described by Jon above. The horns were built in sections with a thick cork covering throughout.
To get into sound of PM series
Just installed the DX3 in the Azurahorn without front part, the extra middle range going through the long horn is actually enjoyable, more body than my corner loaded all-fun-horn, bigger sound with classical.
Now my question is how to get the most balanced sound from Lowther PM series as the PP horn doesn't have a back chamber.
The option can be (don't think I have the luxury to try each one).
PM5A without front horn,
PM2A with front horn same as what Martin is using now
PM4A with front horn (is this really the ultimate choice other than field coil).
Any recommendations?
Just installed the DX3 in the Azurahorn without front part, the extra middle range going through the long horn is actually enjoyable, more body than my corner loaded all-fun-horn, bigger sound with classical.
Now my question is how to get the most balanced sound from Lowther PM series as the PP horn doesn't have a back chamber.
The option can be (don't think I have the luxury to try each one).
PM5A without front horn,
PM2A with front horn same as what Martin is using now
PM4A with front horn (is this really the ultimate choice other than field coil).
Any recommendations?
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Consider EnABLing your Lowther drivers
I just saw this thread of posts.
I would like to add that one should consider the EnABL treatment of Lowther cones. My experience of the EnABL treatment of DX4s is that it was a larger improvement than going from a backhorn to an open baffle. It probably is a (much?) larger improvement than the differences between the various flavors of Lowther drivers, except, perhaps, the field coils. The one caveat about this treatment is that not everyone who has heard the treatment liked the results. In my system, the EnABLed DX4 drivers were a significant improvement over the nonEnABLed ones, and I did not notice any increased harshness that others reported nor other negative side effects.
Retsel
I just saw this thread of posts.
I would like to add that one should consider the EnABL treatment of Lowther cones. My experience of the EnABL treatment of DX4s is that it was a larger improvement than going from a backhorn to an open baffle. It probably is a (much?) larger improvement than the differences between the various flavors of Lowther drivers, except, perhaps, the field coils. The one caveat about this treatment is that not everyone who has heard the treatment liked the results. In my system, the EnABLed DX4 drivers were a significant improvement over the nonEnABLed ones, and I did not notice any increased harshness that others reported nor other negative side effects.
Retsel
A/C field coil
The whole system of the field coil is designed for DC. Trying to change that to AC, and having an separate amplifier run it, will create all kinds of problems. The coil is a huge inductor, and does not want to respond quickly to any signals, it is actually very good at flattening out any power supply variations because of its nature. Extremely difficult to do, and then not sure if the results would be good or bad. I will let you run this experiment.
Hi There,
It may be a completely nuts idea, but would there be any advantage in modulating the PSU of the Field coil with the signal, even varying the amount of modulation and what effect it has on the sound.
The whole system of the field coil is designed for DC. Trying to change that to AC, and having an separate amplifier run it, will create all kinds of problems. The coil is a huge inductor, and does not want to respond quickly to any signals, it is actually very good at flattening out any power supply variations because of its nature. Extremely difficult to do, and then not sure if the results would be good or bad. I will let you run this experiment.
Recommendations
The minimal risk entry is the PM2A, because Martin has done it, and it works. IMHO, the 5A or the 4A in a front horn with the large "lightbulb" phase plug would work better. Since you are in Canada, I cannot easily loan you anything. Did you ask Martin if he ever tried other drivers?
The minimal risk entry is the PM2A, because Martin has done it, and it works. IMHO, the 5A or the 4A in a front horn with the large "lightbulb" phase plug would work better. Since you are in Canada, I cannot easily loan you anything. Did you ask Martin if he ever tried other drivers?
Yes, but think of the whole; field coil+pole piece+voice coil - that is just like any AC motor, you could even run it with voice coil shorted and applying signal to field coil terminals.
My reasoning is as with motor...Ah forget about it, maybe I'm hallucinating from the lack of sleep.Night all.
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Yes. The reciprocity principle applies.
Jan Didden shared a paper with me from the last AES
convention presenting just such a device. IIRC it was from
the boys at Bohlander Graebner/Wisdom Audio, but I'd
have to search for it to confirm that.
Also IIRC, it was a fixed electromagnet circuit driven by
the audio signal and had a shorted moving voice coil.
There were some surprisingly high claims to efficiency for
it.
Jan Didden shared a paper with me from the last AES
convention presenting just such a device. IIRC it was from
the boys at Bohlander Graebner/Wisdom Audio, but I'd
have to search for it to confirm that.
Also IIRC, it was a fixed electromagnet circuit driven by
the audio signal and had a shorted moving voice coil.
There were some surprisingly high claims to efficiency for
it.
Yes. The reciprocity principle applies.
Jan Didden shared a paper with me from the last AES
convention presenting just such a device. IIRC it was from
the boys at Bohlander Graebner/Wisdom Audio, but I'd
have to search for it to confirm that.
Also IIRC, it was a fixed electromagnet circuit driven by
the audio signal and had a shorted moving voice coil.
There were some surprisingly high claims to efficiency for
it.
T'was not hallucination then.
Jon Ver Halen can also comment on EnABL'd Lowthers. I would caution anyone contemplating this process to be aware of just how explosive the dynamics become. We are speaking of horn loaded compression driver levels of response when the DX4 is treated. The PM6A silver VC 16 ohm is by far my favorite of the 4 that I have personally treated. I understand that a few folks have done Lowthers on their own, but have never heard a peep from any of them. Would like to.
I have attached my own take on the ultimate Lowther speaker. Pm6A nude crossed to an Eminnence Delta 8 and a cardioid loaded U baffle and two Tang Band woofers also in Cardioid. Cross over will be from a reworked Berringer DCX 2496 with op amps replaced with 24 step isolation style transformer attenuators, for level matching out to a triamp set up. Another stepped attenuator for the master volume control.
We will see how this works out by misd summer, work on the DCX begins after Christmas, along with the relatively simple cabinetry work. The drivers are all EnABL'd, of course.
I have to tell you, a nude Lowther is the lovliest sounding, most breathtakingly lifelike speaker I have encountered.
Bud
I have attached my own take on the ultimate Lowther speaker. Pm6A nude crossed to an Eminnence Delta 8 and a cardioid loaded U baffle and two Tang Band woofers also in Cardioid. Cross over will be from a reworked Berringer DCX 2496 with op amps replaced with 24 step isolation style transformer attenuators, for level matching out to a triamp set up. Another stepped attenuator for the master volume control.
We will see how this works out by misd summer, work on the DCX begins after Christmas, along with the relatively simple cabinetry work. The drivers are all EnABL'd, of course.
I have to tell you, a nude Lowther is the lovliest sounding, most breathtakingly lifelike speaker I have encountered.
Bud
Attachments
Lets take it a step further...
Consider using one amplifier to drive both voice and field coils with the same signal. There will be an issue with impedance matching, so one would have to take that into consideration. In classic speaker you have a static magnetic field of the pole piece interacting with alternating field produced by the voice coil. If both of coils (voice and field) were driven you'd get more effective motor system. Thiele and Small parameters ?! Any comments?
Peter.
Consider using one amplifier to drive both voice and field coils with the same signal. There will be an issue with impedance matching, so one would have to take that into consideration. In classic speaker you have a static magnetic field of the pole piece interacting with alternating field produced by the voice coil. If both of coils (voice and field) were driven you'd get more effective motor system. Thiele and Small parameters ?! Any comments?
Peter.
I would recommend using a Lundahl amorphous coil transformer for the field coil and a very high information through put output, with slightly less extreme magnetic performance so you could afford to maximize the data retention through capacitive coupling. This goes for both sold state and tube amp designs. See Gary Pimm's Tabor amplifier for his intial cut on SS with transformers. A very impressive amp, and not slighting Nelsons work here, at all.
Bud
Bud
Retzel,
I'm not Bud, but I think I can answer your question.
The Lowther doesn't have any baffle, it's a "No-Baffle" Open Baffle design that some have been using for awhile. The driver is held in place by a heavy clamp around the magnet structure. I've never heard one, but people for whom I have a lot of respect say it's very good.
Best Regards,
TerryO
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Aha... so a nude Lowther assumes no baffle.
Using a Lowther with a lower strength magnet to enable a no baffle design seems a little like throwing out the baby with the bathwater. It seems to me that the best sound from Lowthers is from those Lowther drivers with stronger magnets. Rather than surrendering the great sound of the big magnet Lowthers over baffle problems, one should work on fixing the baffle problems. I have been collecting ideas about what makes baffles good versus what contributes to their problems and I intend on experimenting on better baffle designs. It could be, though, that there will always be compromises with baffles and the baffleless designs will be a viable alternative.
Retsel
Using a Lowther with a lower strength magnet to enable a no baffle design seems a little like throwing out the baby with the bathwater. It seems to me that the best sound from Lowthers is from those Lowther drivers with stronger magnets. Rather than surrendering the great sound of the big magnet Lowthers over baffle problems, one should work on fixing the baffle problems. I have been collecting ideas about what makes baffles good versus what contributes to their problems and I intend on experimenting on better baffle designs. It could be, though, that there will always be compromises with baffles and the baffleless designs will be a viable alternative.
Retsel
Retsel,
My take on a "nude" Lowther is attached to post #131. There is a baffle, as a connection to the mid bass driver. The LOwther will be floating with respect to that baffle board. Care has been used in developing the shape of the baffles involved, to help eliminate the baffle step problem for both mid bass and bass driver sections. The Karlson vent is actually used in the bass cardioid U baffle to present a range of distances for what is left of the coupling from back to front, after the severe damping of the cotton wall batting material has quelled the back wave. A similar sort of distance averaging was done with the mid bass cardioid U baffle.
The reason for the nude Lowther is because, once EnABL'd, it has a very horn like dynamic quality and is quasi omnidirectional, with the "front side" of the signal painted on the very deep, colorful and detailed "body" of the music. I was fascinated with this aspect as I treated these and, before them, Jon Ver Halen's PM6A drivers and have been thinking about how to implement it since. Just my notion, passed around to cause others to think, literally, beyond the box.
Bud
My take on a "nude" Lowther is attached to post #131. There is a baffle, as a connection to the mid bass driver. The LOwther will be floating with respect to that baffle board. Care has been used in developing the shape of the baffles involved, to help eliminate the baffle step problem for both mid bass and bass driver sections. The Karlson vent is actually used in the bass cardioid U baffle to present a range of distances for what is left of the coupling from back to front, after the severe damping of the cotton wall batting material has quelled the back wave. A similar sort of distance averaging was done with the mid bass cardioid U baffle.
The reason for the nude Lowther is because, once EnABL'd, it has a very horn like dynamic quality and is quasi omnidirectional, with the "front side" of the signal painted on the very deep, colorful and detailed "body" of the music. I was fascinated with this aspect as I treated these and, before them, Jon Ver Halen's PM6A drivers and have been thinking about how to implement it since. Just my notion, passed around to cause others to think, literally, beyond the box.
Bud
Hi There,
It may be a completely nuts idea, but would there be any advantage in modulating the PSU of the Field coil with the signal, even varying the amount of modulation and what effect it has on the sound.
I have a buddy that has been egging me on to try this and have heard rumors of a 36" driver at the 1939 worlds fair that used the field coil motor as a load for a SET and had no voice coil connections.
dave