I've just bought a pair of Lowther PM7C but I discovered that they have 2 different cones.
I have lot of doubts about what to do, as having them reconed by Lowther is too pricey:
I can rely on a good technician who can work and fine tune them, but the decision of what to do is mine... 🙂
Thank you in advance for any help!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I have lot of doubts about what to do, as having them reconed by Lowther is too pricey:
try to make them work as a stereo pair would be possible? what are your experience?
change the cone with good aftermarket ones (I've found nice ones on Facebook from hard Lowther modders), any experience?
I can rely on a good technician who can work and fine tune them, but the decision of what to do is mine... 🙂
Thank you in advance for any help!
Other info that can be useful:
Ciao
- I know the cones have different voice coils, one seems silver and one seems enamel aluminium;
- I also know one voics coil is deeper, so I'll have to add spacers for allow good excursion;
Ciao
Try to make it work....
Clearly they are not both C cones, as the different former length suggests that they were fitted to different magnets. I would try using spacers to line up the voice coil in the gap for the cone with the longer former and see how they work.
The different color voice coils may mean nothing. I recently purchased a set of DX65 cones from Lowther made with aluminum voice coils and they were copper colored - I presume that they were copper coated.
A good reason for using these older cones - some of the older Lowther cones were treated just right to make the sound reproduction (midrange in particular) simply glorious. One trick you can try is making a cut in the edge of other whizzer cone and straightening the rolled back whizzer cone. If you don't like it straightened, you can fold it back.
If you have already tried to make them work, let us know how they sound.
Clearly they are not both C cones, as the different former length suggests that they were fitted to different magnets. I would try using spacers to line up the voice coil in the gap for the cone with the longer former and see how they work.
The different color voice coils may mean nothing. I recently purchased a set of DX65 cones from Lowther made with aluminum voice coils and they were copper colored - I presume that they were copper coated.
A good reason for using these older cones - some of the older Lowther cones were treated just right to make the sound reproduction (midrange in particular) simply glorious. One trick you can try is making a cut in the edge of other whizzer cone and straightening the rolled back whizzer cone. If you don't like it straightened, you can fold it back.
If you have already tried to make them work, let us know how they sound.
A quick update about the project:
A spacer was added to make the deeper voicecoil works (one is exactly 5.3mm longer)
The output seems quite good:
C series voice coil:
The longer voice coil:
Tried the usual rough test with mono tracks to check if they can work as a pair:
The result seems fine, I've had to check twice if the sound was coming from the t-amp 🙂
So far so good, now I have to decide which case to build.
Nice going! Those responses look great! (except for the roller coaster effect which is not all that unusual for a Lowther....)
One thing to try, and it can be done pretty quickly, is to put them into an open baffle. A guy named Dick Olsher designed an open baffle speaker for the DX4 Lowthers, including the crossover networks. You can get response down to 150 hz this way (and even lower - you just start running out of x-max) and the sound is really transparent this way - I found the open baffle to sound more transparent than my DX4s mounted in backhorns (Hedlund). If used in an open baffle, you need to high pass them and you would need a woofer to go with them then.
Your drivers are like some other Lowthers which have a peak right at 2 khz - the famous Lowther "shout." Dick Olsher designed a trap to knock that down. I would put them into a speaker first before worrying about any crossover.
I see that the whizzer cones do not have the rolled edge - maybe they are older then, although the foam surrounds seem very good. I suspect that they were reconed and maybe even recently. When I unfurled the rolled back whizzer, the high frequencies sounded better, but mine are mounted in front waveguides which is supposed to be better with the straight edge whizzer.
Anyways, just some comments and some of my experiences.
Retsel
One thing to try, and it can be done pretty quickly, is to put them into an open baffle. A guy named Dick Olsher designed an open baffle speaker for the DX4 Lowthers, including the crossover networks. You can get response down to 150 hz this way (and even lower - you just start running out of x-max) and the sound is really transparent this way - I found the open baffle to sound more transparent than my DX4s mounted in backhorns (Hedlund). If used in an open baffle, you need to high pass them and you would need a woofer to go with them then.
Your drivers are like some other Lowthers which have a peak right at 2 khz - the famous Lowther "shout." Dick Olsher designed a trap to knock that down. I would put them into a speaker first before worrying about any crossover.
I see that the whizzer cones do not have the rolled edge - maybe they are older then, although the foam surrounds seem very good. I suspect that they were reconed and maybe even recently. When I unfurled the rolled back whizzer, the high frequencies sounded better, but mine are mounted in front waveguides which is supposed to be better with the straight edge whizzer.
Anyways, just some comments and some of my experiences.
Retsel
Thank you very much Retsel.
I have an OB idea, but with my Saba Greencones (Endorphin).
For the Lowther I'm searching for good "fullrange" project.
I don't have much space in my living room (only 4mx5m), so I am thinking about MLTL (from Martin King) or Fidelio.
I know phisic is against me, but Big Fun Horn or Side Vivace are way too big for me...
I have an OB idea, but with my Saba Greencones (Endorphin).
For the Lowther I'm searching for good "fullrange" project.
I don't have much space in my living room (only 4mx5m), so I am thinking about MLTL (from Martin King) or Fidelio.
I know phisic is against me, but Big Fun Horn or Side Vivace are way too big for me...
Thank you.
I'm a member already, and I'm really enjoying browsing!
They also helped a lot with the cones problem, and soon I'll be able to try some nev cones (stay tuned...).
I'm a member already, and I'm really enjoying browsing!
They also helped a lot with the cones problem, and soon I'll be able to try some nev cones (stay tuned...).