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yup, you may as well pour the gasoline on them now and be done with it 😀
Well the Moon Onkens with the BSC sound great. I regret being prejudiced against BSC at the start because of some purist notions and too much first time builders pride. It brings the necessary balance to the speakers and they sound very nice.
I'm using them with my own designed and built amplifier so there are a lot of variables but I'm now a lot happier.
They're a good size, I wouldn't want them that much larger so if I had to do this over I might look for drivers that would perform well in a similar volume.
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A year on and the Moon Onken's are no longer meeting my needs. The issue is they still sound bass shy and curing the 7kHz peak with a coil & resistor is taking the magic out of it.
I came across this: Fostex FE127E Fullrange Loudspeaker Driver
The author measures the T/S parameters of four FE127E drivers and finds them to deviate a fair bit from the manufacturers spec. I tried loading up these into the on-line BR calculator I used when I designed the enclosure and find that the enclosure is unsuitable for these drivers, if the spec. are correct. See attached - no bass extension.
So I am going to take these drivers out of these boxes. This will have the benefit of generating two new projects. One project will be to find new drivers for the existing boxes, which probably can be tweaked in terms of the port dimensions. A good candidate is already in mind for this. The second project will be to build a new enclosure or two to take advantage of the FE127's that I now have available to be re-purposed, candidates include an OB, a larger volume Fonken, or even a dipole.
I came across this: Fostex FE127E Fullrange Loudspeaker Driver
The author measures the T/S parameters of four FE127E drivers and finds them to deviate a fair bit from the manufacturers spec. I tried loading up these into the on-line BR calculator I used when I designed the enclosure and find that the enclosure is unsuitable for these drivers, if the spec. are correct. See attached - no bass extension.
So I am going to take these drivers out of these boxes. This will have the benefit of generating two new projects. One project will be to find new drivers for the existing boxes, which probably can be tweaked in terms of the port dimensions. A good candidate is already in mind for this. The second project will be to build a new enclosure or two to take advantage of the FE127's that I now have available to be re-purposed, candidates include an OB, a larger volume Fonken, or even a dipole.
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The paper cone version looks nice, but it's rated at 4Ohm and that's not what I'm looking for. I'm wondering about the new GenIII CHR-70
Which it seems is more an indication that his measure system does not match that of the manufacturer. Those are similar to what i get with my kit.
One must keep in mind that T/s are not scaler numbers but a curve that is f(V,weather).
Attached are measures of the same FE127eN by myself and by Mark Fenlon using one of the 2 industry standard pieces of kit.
dave
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Preliminary data from the test builds. http://www.diyaudio.com/forums/markaudio/184372-chr-70-generation-3-coming-soon-13.html#post2545820
It should be noted that the typical computer baed measures on Mark's drivers are a lot closer to what he publishes. I can only suggest that this is because with his drvers f-f(V) is much closer to a horizontal line.
dave
Thanks Dave, missed that by one page.🙂
Hope this WinISd plot show enough detail. The two CHR-70 plots are very close. All three plots are the same box, 6L Q3B.
jeff
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you have two sets of numbers here which deviate from the factory, which set of numbers would you suggest I use when considering a box design ?
what I do know, the current driver - box combination is not providing the results that others talk of and I suspect it's because the current box was designed based on factory spec.
I tend to use factory numbers. For the FE127e all my designs used them. But i also am very concious that a design needs to be tolerent of changing T/S with dynamics.
dave
dave
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When I looked at your Fonken I did find all the dimensions to be consistent with a BR calculator using the factor spec but wasn't sure that was the whole story. Still, there is an issue with inadequate bass response for my HT application - they run out of xmax for starters if I allow them to see the full signal and using a high pass filter (built into my HT system - used for 'small' speakers) doesn't move things in the right direction. I'm keeping my eye on them new CHR-70 mk IIIs as potential candidates.
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I've ordered a pair of CSS EL-70's to try in these boxes. It's not ideal because the boxes are already built of course and so it's hard to change the tuning (effective length about 17cm, effective diameter about 4.5cm, box volume about 6 litres). I figure I need to reduce the area of the ports (effective diameter about 3.5cm to 3.8cm), which I'll try by inserting wood into the existing port openings. If this works as per the 'theory' I should see the F3 pushed down from 80Hz to 60Hz (similar gains to F10). Whatever, it will be different. If it's better I may buy more EL-70's.
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I decided to do a rudimentary impedance measurement of the FE127E in the box to see if it was close what was expected.
The expected result was simulated with an on-line calculator: Loudspeaker enclosure calculating with Thiele Small parameter
I used a sine wave generator playing though my TGM3 amplifier, an 8R resistor in line with the ground wire to the speaker and I measured the rms voltage across it using a DMM.
Simulated impedance peaks: 36 Hz, 110 Hz (see red lines in first attached plot)
Measured impedance peaks: 35 Hz, 110 Hz (measured impedance is on a relative, linear scale)
Seems a reasonable match ?
The expected result was simulated with an on-line calculator: Loudspeaker enclosure calculating with Thiele Small parameter
I used a sine wave generator playing though my TGM3 amplifier, an 8R resistor in line with the ground wire to the speaker and I measured the rms voltage across it using a DMM.
Simulated impedance peaks: 36 Hz, 110 Hz (see red lines in first attached plot)
Measured impedance peaks: 35 Hz, 110 Hz (measured impedance is on a relative, linear scale)
Seems a reasonable match ?
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I've now swapped out the old drivers for the EL-70 and it's looking like a very worthwhile change. After 3 hours of driver burn-in I can already tell that these are going to be the final drivers for this box design.
http://www.diyaudio.com/forums/full-range/192394-mmar-kel70-vs-mar-kel70.html
http://www.diyaudio.com/forums/full-range/192394-mmar-kel70-vs-mar-kel70.html
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EL-70 is NOT passing my long term listening test ?
Well I have to report now, after many listening sessions that I am not quite so happy with the EL-70. Still using my single ended triode amplifier.
I'm very surprised myself.
The issue is something irritating me in the treble. It's very difficult to hear it, but after 3 to 4 hours of listening there is something fatiguing that I can hear. I had this with the FE127 in spades - fatigue set in within a minute or so with that driver. I never had fatigue with the Fountek FR88EX (using triode amp or my TGM1)
The nearest explanation I have for this is here: http://www.diyaudio.com/forums/full-range/208826-el70-frequency-response-measurements.html
Evidence of a cone break-up mode around 6kHz - 7kHz. This is just where the FE127 has a noticeable break-up mode.
It's not something I think you'd notice easily by listening, but it appears I am very sensitive to this kind of thing. I'm not saying I don't recommend the driver, it's really something special, the bass is really good and CSS has the best service I ever encountered, but I seem to have some kind of super-sensitivity despite getting older....
Well I have to report now, after many listening sessions that I am not quite so happy with the EL-70. Still using my single ended triode amplifier.
I'm very surprised myself.
The issue is something irritating me in the treble. It's very difficult to hear it, but after 3 to 4 hours of listening there is something fatiguing that I can hear. I had this with the FE127 in spades - fatigue set in within a minute or so with that driver. I never had fatigue with the Fountek FR88EX (using triode amp or my TGM1)
The nearest explanation I have for this is here: http://www.diyaudio.com/forums/full-range/208826-el70-frequency-response-measurements.html
Evidence of a cone break-up mode around 6kHz - 7kHz. This is just where the FE127 has a noticeable break-up mode.
It's not something I think you'd notice easily by listening, but it appears I am very sensitive to this kind of thing. I'm not saying I don't recommend the driver, it's really something special, the bass is really good and CSS has the best service I ever encountered, but I seem to have some kind of super-sensitivity despite getting older....
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Yes, me and others have noted on other threads that peaks up in the voice sibilance BW can be fatiguing to downright irritating if you have tinnitus.
GM
GM
You might want to try the FX120. I went to these from the FE127, and all the nasty bits that you described went away.
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The FX120 looks very nice and if it sounds good then it's worth the cost to me.
I noticed an even sexier looking F120A is also available - it's twice the price, I wonder if it's twice as nice.
Both drivers appear to have been around for awhile, should I be nervous about Fostex pulling the plug or updating them anytime soon ?
I noticed an even sexier looking F120A is also available - it's twice the price, I wonder if it's twice as nice.
Both drivers appear to have been around for awhile, should I be nervous about Fostex pulling the plug or updating them anytime soon ?
the 120A is AlNiCo, so that's why the hefty price increase. If you think in terms of amplifier power where doubling it only has a minor audible affect, then yes, it's worth the price, though to my ears this only applies if driving it with a SET amp.
GM
GM
I can whole heartedly recommend the FX120, and I am not a big believer in fullrange speakers. For certain types of music (jazz, female vocals) they are stunning. So long as you don't expect high volume levels, I think that you will enjoy these for all genres of music. They have a much more "invisible" sound than they FE127. Delicate, yet smooth and full. Mine were enabled by Dave at Planet10.
I sold mine before I had the chance to put them in your moon-onken cabs, as I did not have the need for them in the house. I had planned stereo subs also. I did not want too many boxes in the living room, as standmount speakers and babies and toddlers do not mix. Maybe one day... Might be ideal in the office.
I have heard that the F120A is nice, but not a significant improvement on the FX120 to be worthwhile. I have not heard them myself.
I have no idea whether they will be superceded by Fostex anytime soon. If you buy them and love them, just buy a spare set if it worries you.
I sold mine before I had the chance to put them in your moon-onken cabs, as I did not have the need for them in the house. I had planned stereo subs also. I did not want too many boxes in the living room, as standmount speakers and babies and toddlers do not mix. Maybe one day... Might be ideal in the office.
I have heard that the F120A is nice, but not a significant improvement on the FX120 to be worthwhile. I have not heard them myself.
I have no idea whether they will be superceded by Fostex anytime soon. If you buy them and love them, just buy a spare set if it worries you.
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