Daniel,
I have not heard of this before. I think Doug used a very nice big air core coil. Could you enlighten us or provide a link to a description of this?
Well, ordered the coils and resistors for the Fountek 85's. Hope they get here. It seems the parts for the 125's were stolen.
That's bad...really bad (who would steal xo parts?)
So gave up on the huge coils, found a pair of .75mh 14 gauge and just swapped them out; I didn't hear the ghost warble sound (which was very faint in the first place).
They sound great, good bass, very nice midrange; little boxes. I do think I'm dancing around a small problem; like to try the notch filter next.
Might spray thin layer of clear Krylon on them, very thin.............
So gave up on the huge coils, found a pair of .75mh 14 gauge and just swapped them out; I didn't hear the ghost warble sound (which was very faint in the first place).
They sound great, good bass, very nice midrange; little boxes. I do think I'm dancing around a small problem; like to try the notch filter next.
Might spray thin layer of clear Krylon on them, very thin.............
Who would steal XO parts? Ha! You haven't seen some of my more madcap creations (insert Igor surrounded by enormous transformers hauling on huge lever at this point : 'yeth mathder. Shrap it tho a thable and hith it with a bolth of lightning...') The damn things would cost two or three times what the drivers do in terms of quality components. Very tempting for the light-fingered brigade.
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Ringing
This is a bit tardy but the problem of damping speaker baskets is not eliminated by conventional mounting, just reduced. So the tick still has a frequency of its own, which will without fail add and subtract to/from the many other anomalies running around in a speaker system. Hence the latest and greatest bass-mid drivers have struts running from the perimeter to the magnet structure, not zigging here and there to extract maximum strength from the minimum of mild steel. Stiffness and damping? Yeah, not so much. Ironically my old Wolverine drivers, budget EV that they were, are built like the trick new stuff. Undamped flex can be heard. Measurement is something else.
This is a bit tardy but the problem of damping speaker baskets is not eliminated by conventional mounting, just reduced. So the tick still has a frequency of its own, which will without fail add and subtract to/from the many other anomalies running around in a speaker system. Hence the latest and greatest bass-mid drivers have struts running from the perimeter to the magnet structure, not zigging here and there to extract maximum strength from the minimum of mild steel. Stiffness and damping? Yeah, not so much. Ironically my old Wolverine drivers, budget EV that they were, are built like the trick new stuff. Undamped flex can be heard. Measurement is something else.
Well, I've seen tiny value polyester caps parallel with the inductors in many crossover examples, and I have personally tried this inexpensive type of polyester capacitor with useful results. Since I don't have either your inductor or your speaker, I couldn't tell you exactly which cap to use, so consider it an experiment. The effect is mild, but it might be just barely enough to reverse the problem described. I do not know if the cap itself damps the inductor or if it allows the amplifier to better damp the inductor and cables. There's a lot that I don't know.
Okay, try your huge coils with a paralleled resistor and a paralleled RC (accomplishes the notch filter). Actually, the RC should be passing your treble intact more or less. To defeat that warble, you might be using resistors like 2 ohms or smaller parallel with the inductor; however, it will do something. And, what it will do is different depending on if you put it before or after your 0.75mh filter.
In case I wasn't clear, bypass the problem pitches with a cap or RC (or both simultaneously!) to carry them around (bypass) the inductor so that those pitches (that warbled) aren't affected by the inductor.
P.S.
I've actually used such huge coils with less than 1 ohm resistance and a small cap added. It was merely to compensate for a change in amplifier without re-working anything. The chip amp was indeed clear but had a slight shout and the filter stopped it from overdamping the speaker. Well, it sounded more like a parallel amp (small value 0.33R ballast, aka "output mixer" is typical of a parallel amp). It looked like a big crossover expense for doing almost nothing, but that "almost" was more laid back clearer voice band. Oh my! Sure, I could have altered the amplifier's power supply (directly alters speaker support); however, the crossover parts were expedient, specific and convenient. 🙂
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I was having some success with the .75 coils, but I think they are also too large (the highs were lacking) - but that said, without them, there is a bit of "shouting" in some of the songs. So narrowing this down, will try the RC next.
Was listening to them last night; right before a rain storm (low barometric pressure) they sounded like a 12" woofer- 3 way (chuckle).
Was listening to them last night; right before a rain storm (low barometric pressure) they sounded like a 12" woofer- 3 way (chuckle).
Highs lacking is not the coil size, it is the need for the bypass Daniel is talking about. Too small a coil will give a hump at the bottom of the compensation range, in the mid hundreds.
up-date
wow wow wow... game changer: changed player, amp, pre amp.
In short; these are fantastic drivers, what sound!!. Turned my shop into a HyFy store, quite amazing really.
Looking forward to auditioning the coated drivers.
wow wow wow... game changer: changed player, amp, pre amp.
In short; these are fantastic drivers, what sound!!. Turned my shop into a HyFy store, quite amazing really.
Looking forward to auditioning the coated drivers.
All vintage:
*Luxman M-117, only used it for 8Ohm BR DIY subwoofers in the HT so never pushed it hard. (one of the "full range guys" thought that this would probably would be the best of the transistor amps).
*Rotel RC-870 pre amp which is entry level, except my buddy that works on fighter jet radios replace the Op amps. (this fellow is one that got me going with box sizes and tuning - square boxes/PCV ports)
*Kyocera DA710 CX.
I haven't heard anything sound this good in a long time. I played with the BSC with clip leads (on/off) it sounded great both ways. The mid-range is stunning, getting nice bass extension. When I look to the wall, my mind is thinking 3' tower speakers, not 14-1/4" tall speakers.
*Luxman M-117, only used it for 8Ohm BR DIY subwoofers in the HT so never pushed it hard. (one of the "full range guys" thought that this would probably would be the best of the transistor amps).
*Rotel RC-870 pre amp which is entry level, except my buddy that works on fighter jet radios replace the Op amps. (this fellow is one that got me going with box sizes and tuning - square boxes/PCV ports)
*Kyocera DA710 CX.
I haven't heard anything sound this good in a long time. I played with the BSC with clip leads (on/off) it sounded great both ways. The mid-range is stunning, getting nice bass extension. When I look to the wall, my mind is thinking 3' tower speakers, not 14-1/4" tall speakers.
Yes good point - sorry
Pics #28 - #33 (only 11 pieces of wood, not counting the dowel)
http://www.diyaudio.com/forums/full-range/217121-please-recommend-desktop-fullranger-3.html
Started a 19" x 19" x 17" deep, mini 3 shelf rack today.
Pics #28 - #33 (only 11 pieces of wood, not counting the dowel)
http://www.diyaudio.com/forums/full-range/217121-please-recommend-desktop-fullranger-3.html
Started a 19" x 19" x 17" deep, mini 3 shelf rack today.
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For my next trick....
I wonder how well I can apply what I have learned about cone breakup to the venerable Dayton RS-150. This is a very nice driver but requires a very low crossover or a couple of notches. Can it be tamed mechanically?
I wonder how well I can apply what I have learned about cone breakup to the venerable Dayton RS-150. This is a very nice driver but requires a very low crossover or a couple of notches. Can it be tamed mechanically?
Aluminium cone ? Not likely, at least not with foam strips, as the required amount of added damping would need to be huge due to lack of internal damping and stiffness of the material.
With paper cones we're just tweaking the already fairly well damped breakup, and because the paper is so soft (compared to aluminium) it doesn't take much damping to control it.
Feel free to experiment and report back though. 🙂
I have an extra, so that was the intention. Foam is just for testing. My actual material is artist gesso. Being "just a woofer" I don't mind if I add a tad of mass. My goal is to get it to behave reasonably with a 2 to 2.5K second order crossover. My current 1600 third does OK, but not great. A 4th plots better, and many published designs use sub 1K and big notches. A bit too tough on real tweeters. ( The Vifa's I used for sure!). So can I get a handle on the first 6K mode, maybe I can deal with the 10K by just being far enough out. We shall see.
Quick test with foam, 4 and 6 dB improvements at 6200 and 9300 respectably. So I am doping the back side of the cone. This will take some time due to drying times. Of course, what it does to the T/S parameters will be of interest too. Adding a couple grams I expect.
Yes, it works. Several things. As is logical, it moved the peaks down in frequency, which is not a good thing, but it also cut them down by 8 to 10 dB. It also decreased the top end output overall. If this were a fullrange, that would not be good. When you tap on the cone, it sounds more like a paper cone.
I also did very careful measurements to see if the Mortite trick on the edge of the magnet worked. Yes. It took out a lot of little wiggles in the 1 to 2K range. All less than a dB, but it did smooth things just a tad. It sure did not hurt. It might have damped the shield cup over the magnet just a tad. Tapping it suggests so. I do not like the space left under the cup.
I put two coats on front and back and a third on the first 5 mm around the surround front and back. It is ugly. When I treat the other pair, I will do all the work on the back.
So, doping worked on the paper cones of the Fostex 125's. It worked taking a ring out of the dustcaps in the Fountek 85's, and now on the RS150's. I would have to conclude this is a reasonable process. Total disclosure would say it did nothing for the Sony drivers, but these 69 cent drivers have such other problems, I don't think the cone breakup is significant.
I also did very careful measurements to see if the Mortite trick on the edge of the magnet worked. Yes. It took out a lot of little wiggles in the 1 to 2K range. All less than a dB, but it did smooth things just a tad. It sure did not hurt. It might have damped the shield cup over the magnet just a tad. Tapping it suggests so. I do not like the space left under the cup.
I put two coats on front and back and a third on the first 5 mm around the surround front and back. It is ugly. When I treat the other pair, I will do all the work on the back.
So, doping worked on the paper cones of the Fostex 125's. It worked taking a ring out of the dustcaps in the Fountek 85's, and now on the RS150's. I would have to conclude this is a reasonable process. Total disclosure would say it did nothing for the Sony drivers, but these 69 cent drivers have such other problems, I don't think the cone breakup is significant.
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