Your sim is looking good, Bill! I never tried pushing L3 that high, but it seems to be effective. If you wind up needing a little more "sparkle", I would consider lowering it a little.
Keep an open mind, but don't let your brain fall out.
Your sim is looking good, Bill! I never tried pushing L3 that high, but it seems to be effective. If you wind up needing a little more "sparkle", I would consider lowering it a little.
Thanks, Scott! I was thinking the same thing about L3, wondering why such a huge increase in value to get a flat response. But then I dug a little deeper and examined the manufacturers' data sheets more closely for the Neo3W verses the Neo3 PDR. Turns out that there is a huge difference between the two in the 5 to 20kHz region. The larger value is actually needed to tame down the much hotter response of the Neo3W. I've attached my on-axis measurement showing the peak. Also attached is a slightly revised 3 pane showing what would happen if I dropped L3 down to 0.1mH.
I only tested one tweeter so far, so this may be an anomaly. My measurement, however, seems consistent with the manufacturers' data sheet. I will let you know how it sounds (and measures) when I get both tweeters connected with the final xover in place. It could also be that the tweeter that I just happen to use for measurements is out of spec in the 5-20k region. Bill
Got up to 62F today, so I sprayed several thin coats of lacquer outside in the garage. The Sealcoat I sprayed last week helped a little, but the cabs still need more. Soft knotty pine soaks up finish like a sponge, especially the knotty areas. Used up an entire quart of lacquer, so I picked up another can for tomorrow. This will give me a change to sand the cabinets down with 220 before hitting them with additional coats. The lacquer I am using is designed for brushing, so I am thinning it out quite a bit with lacquer thinner (about 33% thinner 67% lacquer).
Slowly but surely, my project is nearing completion:
I received my xover parts order a few days ago and started laying out the parts on my removable rear panel. After trying several layouts, it became clear that I simply needed more room. My charge coupling experiment doubled the number and size of all caps, so I needed to come up with some idea to conserve space.
After thinking about it for a while, I decided to glue my caps, two at a time, into "skyscrapers." As long as I had some extra vertical space, why not use it?
So, I silicone glued top & bottom 1/4" masonite "end caps" on each PP cap. Then I drilled several holes for mounting, wires, and terminal strips. I used a dremel tool to cut two "trenches" on the bottom masonite board to keep the wiring flush. Mounting is with 4 small 6-32 screws and the 3 basic connection nodes are easily accessed via a 3 position terminal strip on top.
Thanks, Nicholas! I have to admit, however, that I made several wiring errors and re-starts along the way. The 27V switching made loud pops through the tweeter and mids, so I inserted resistors in series with the switches to eliminate the pops. Didn't blow the tweeters and the impedance curve still looks just like my model, so I think I am good to go. Bill
I was reminded of your multi-toggle switched, triple layer xover cake when I wired this up. I do have a few zip ties along the outside edges, however. If you look closely, they are just behind the solder terminals. So I am somewhat guilty as well.
I set the back panel into a staging area to solder up the driver leads. Then I installed the back with multiple #8 x 2-1/2" pocket screws, recessed below the surface by about 1/8" or so. I used a 1/16" thick by 1" light brown foam gasket to match the wood grain. Small pieces of double stick carpet tape held the gasket in place as I tightened the screws.
The picture shows the screws turned in about 1.5" with another 1" or so to go. I used very long screws because pine is a very soft wood and strips out easily.
Finally done. Here are a few actual measurements and a couple completed speaker pics. I've been listening for a few days now and I am really liking the sound so far. Thanks again to Scott for sharing his design.
As can be seen, horizontal polar response is really smooth, especially the ND140/NEO8 transition. Very detailed overall sound quality and smooth response from top to bottom. Bass blends very well with the NEO8s and is very punchy with low distortion, even at a fairly high 95dB playback level at 1 meter (see HD chart). This measurement was with only 1 speaker playing, so this would be a fairly high listening level for both speakers playing in my listening room.
Vertical polar response shows a sharp dip at 2.4kHz in the standing position at 1 meter. But this dip flattens out substantially as you move back to the typical listening distance of 7 to 9 feet or so. I can hear very little difference in tonal balance from my listening chair.
This past week, I did quite a bit of A/B switching to compare the sound of charged verses non-charged coupling caps. If anyone is interested, I will put together a short description of how this comparison worked out. Thanks.
The difference is a slight softening of the sound in the presence region of the NEO3 tweeter, somewhere in the 4-7kHz region, I would guess. I can detect no difference in deep or mid bass transient response, and no difference in the midrange area. Only in the high frequency presence region. With all caps discharged completely, the sound is a little crisper, a little more detailed, almost as if I boosted the 4-7kHz region by about 1 dB or so. I don't know exactly what is going on, but my guess is that this is some type of high frequency transient response difference that is not showing up in my measurements.
So, the Neo3's sound just a little "dull" when I charge the caps. This slight softness actually sounds better to my ears, creating a little more air and sense of depth.
I noticed the same thing when doing comparisons on my Kowaxial speakers. When I get them to the competition at MWAF next month, I think that I am going to completely discharge the CX150's tweeter caps. On these speakers, the tweeters sound a bit dull and lifeless when I charge them up.
Hope this is helpful. This is not what I was expecting.
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Sehlin Sound Solutions
Thanks, Scott! I was thinking the same thing about L3, wondering why such a huge increase in value to get a flat response. But then I dug a little deeper and examined the manufacturers' data sheets more closely for the Neo3W verses the Neo3 PDR. Turns out that there is a huge difference between the two in the 5 to 20kHz region. The larger value is actually needed to tame down the much hotter response of the Neo3W. I've attached my on-axis measurement showing the peak. Also attached is a slightly revised 3 pane showing what would happen if I dropped L3 down to 0.1mH.
I only tested one tweeter so far, so this may be an anomaly. My measurement, however, seems consistent with the manufacturers' data sheet. I will let you know how it sounds (and measures) when I get both tweeters connected with the final xover in place. It could also be that the tweeter that I just happen to use for measurements is out of spec in the 5-20k region. Bill
Slowly but surely, my project is nearing completion:
I received my xover parts order a few days ago and started laying out the parts on my removable rear panel. After trying several layouts, it became clear that I simply needed more room. My charge coupling experiment doubled the number and size of all caps, so I needed to come up with some idea to conserve space.
After thinking about it for a while, I decided to glue my caps, two at a time, into "skyscrapers." As long as I had some extra vertical space, why not use it?
So, I silicone glued top & bottom 1/4" masonite "end caps" on each PP cap. Then I drilled several holes for mounting, wires, and terminal strips. I used a dremel tool to cut two "trenches" on the bottom masonite board to keep the wiring flush. Mounting is with 4 small 6-32 screws and the 3 basic connection nodes are easily accessed via a 3 position terminal strip on top.
InDIYana Event Website
InDIYana Event Website
I was reminded of your multi-toggle switched, triple layer xover cake when I wired this up. I do have a few zip ties along the outside edges, however. If you look closely, they are just behind the solder terminals. So I am somewhat guilty as well.
I set the back panel into a staging area to solder up the driver leads. Then I installed the back with multiple #8 x 2-1/2" pocket screws, recessed below the surface by about 1/8" or so. I used a 1/16" thick by 1" light brown foam gasket to match the wood grain. Small pieces of double stick carpet tape held the gasket in place as I tightened the screws.
The picture shows the screws turned in about 1.5" with another 1" or so to go. I used very long screws because pine is a very soft wood and strips out easily.
Finally done. Here are a few actual measurements and a couple completed speaker pics. I've been listening for a few days now and I am really liking the sound so far. Thanks again to Scott for sharing his design.
As can be seen, horizontal polar response is really smooth, especially the ND140/NEO8 transition. Very detailed overall sound quality and smooth response from top to bottom. Bass blends very well with the NEO8s and is very punchy with low distortion, even at a fairly high 95dB playback level at 1 meter (see HD chart). This measurement was with only 1 speaker playing, so this would be a fairly high listening level for both speakers playing in my listening room.
Vertical polar response shows a sharp dip at 2.4kHz in the standing position at 1 meter. But this dip flattens out substantially as you move back to the typical listening distance of 7 to 9 feet or so. I can hear very little difference in tonal balance from my listening chair.
This past week, I did quite a bit of A/B switching to compare the sound of charged verses non-charged coupling caps. If anyone is interested, I will put together a short description of how this comparison worked out. Thanks.
Bill
The difference is a slight softening of the sound in the presence region of the NEO3 tweeter, somewhere in the 4-7kHz region, I would guess. I can detect no difference in deep or mid bass transient response, and no difference in the midrange area. Only in the high frequency presence region. With all caps discharged completely, the sound is a little crisper, a little more detailed, almost as if I boosted the 4-7kHz region by about 1 dB or so. I don't know exactly what is going on, but my guess is that this is some type of high frequency transient response difference that is not showing up in my measurements.
So, the Neo3's sound just a little "dull" when I charge the caps. This slight softness actually sounds better to my ears, creating a little more air and sense of depth.
I noticed the same thing when doing comparisons on my Kowaxial speakers. When I get them to the competition at MWAF next month, I think that I am going to completely discharge the CX150's tweeter caps. On these speakers, the tweeters sound a bit dull and lifeless when I charge them up.
Hope this is helpful. This is not what I was expecting.
Bill