To perform the Wolf test, I made a separate set of FRD's with the TweeMids flipped 180 degrees. The model is virtually identical, except for a slight peak at 2kHz on the flipped version. I have not ordered parts yet, so I have not listened to see if this makes a difference.
I picked up a carbide tipped 3/8" round nose bit at Menards and cut three 17" long, decorative flutes along the front baffle. This is similar to the three baffle flutes that Dan N. used on his Scimitar speakers, except that his flute spacing distance was much wider than mine (my spacing is 1/2" ctr-to-ctr). I used a plunge router and adjustable guide rail setup to do this.
Of course, Dan's speakers look a lot better than mine, but I am not finished yet. Wait until you see the finished speaker. Next up: Custom base and crossover caddy.
I revised my crossover again using more accurate woofer data using Jeff B's blender program. I talked to Jeff at Indy last year and was able to clear up some of the problems that I was having trying to get the blender to work properly. And this time it actually worked!!
First off, I made sure that I checked the "ALL" mode when making my NF woofer measurement, as John suggested. Then I set up my baffle step model using a 9.625 inch wide baffle instead of the actual 8.625" width to account for the large donut above the tower. Then I merged NF and FF curves over the 500-800Hz range, where both curves are smooth and valid. I included port data in my NF measurement, as the port data affects the response just a little in the 100-200Hz area.
Then I moved the data back into XSim and converted all FRD's over to minimum phase (Hilbert) data. I then re-set the mod delays for the minimum phase files and then re-did the entire crossover. The attached new 3-pane XSim model shows final values using the blended NF/FF woofer data. Quite a bit of difference from my first model, which was based on FF woofer data only. Dropping resistors on the tweeter and mids increased from 5.1 to 8.2 ohms each, a significant increase of baffle step compensation. Good thing that I did not order parts for the first version; it would probably have sounded somewhat "thin" in the mid-bass 100-500Hz region. Thanks again to John and Jeff for the blender tips. I think I "finally" have the blender system figured out!!!
How did you measure and add in the per response to the NF? How far did you measure the NF from?
Ani, The NF woofer cone response was measured with OmniMic tip located about 1/4" from the center of the dust cap. The NF woofer port response was measured with the tip of OmniMic in the center of the port opening, pushed into the port 3/8" In this way, the mic tip was pushed half way into the 3/4" roundover flare of my port.
I added the NF port and NF woofer cone FR data in OmniMic using the "AddedCurves" feature. First, I added the NF woofer cone into OmniMic. Then I used OmniMic's "Sum" function to add the adjusted NF woofer port response to the NF cone response. The NF woofer port response was previous adjusted down 6.8dB and resaved as a new adjusted FRD file. Once the two curves were summed together, I applied a 2.8ms delay to the port response to account for the time it takes for the port output to travel around the cabinet and up to the woofer cone.
Once I had this new merged NF woofer FRD, I loaded it into the Jeff B/Charlie L Blender program and blended it with the FF woofer curve. The result was then saved again with minimum phase data, then loaded into XSim. Once back in XSim, I extracted minimum phase for all FRD's and re-did the xover. It is an exhausting, multi-step process, but it all seems to work out.
EDIT: Forgot to mention, my FF woofer measurement was made at a distance of 1 meter, in the same position that I used for my midrange and tweeter measurements. Mic position and volume control settings were unchanged for these measurements.
Thanks. Always have to make sure I check the "All" mode and not the "Blended" mode in OmniMic when I do my NF curves. That was probably the issue. The slopes and smoothness of the two curves matched up perfectly from 500 to 800Hz this time around.
Made some more progress. This time, Doctor Diffraction gets a new pair of shoes!!
I started with a 6 degree beveled parallelogram:
Then I added two 6 degree angled rails along the two inside sidewalls:
To make the base removable, I bolted it to the bottom with four #8 x 1.5" wood screws:
I gave the base a 0.75 radius roundover all around. This decorative 10.25 x 14.25" base tips the loudspeaker back by 6 degrees. I was not attempting to time align. I simply needed to shift the center of gravity back a bit to compensate for the top heavy donut.
Yes. It's a biggie. I will put it on my bathroom scales to see how hefty (> 1lb of copper, for sure) I was going to go with a cheaper iron core type unit, but wanted to experiment with 15ga air core. DCR is .66 ohms, which is not too bad in the woofer circuit. Not cheap.
I see Madisound has the same value in 14ga with a slightly lower DCR at about the same cost. Too late. Parts already ordered. PE only had the 14ga units up to 2.5mH
Wish I could get my coils to lay that pretty. Might have made up some of the cost using a cheaper npe in that section. What about crossbreeding an npe and poly in that circumstance?
Same. I've tried to hand wind my own, but the wires start to crispy-cross. I also have tried to by-pass npe's with polys in the woofer circuit; but not really sure if this helps. I have not been able to hear a difference in the woofer circuit path. I can only hear cap differences in the tweeter circuit path. You could also try "charge coupling" the npe's in the woofer circuit to see if that helps. I tried this, but could not hear a difference. I could only hear a difference when "charge-coupling" the tweeter caps. Charge-coupling can actually seems to sound worse; it softens the sound quality of the tweeter.
This will be my last update for a while. I'm going to put off the finishing part (sanding, bondo, painting, etc.) until the weather warms up in May. This will involve complete disassembly so that I can spray each speaker part in a variety of contrasting high gloss enamels.
One crossover with measurements is now complete. For mounting the inductors, I'm experimenting with a new wire tie method that uses the "mounting screw" type wire ties. First, I cut a 1/4" thick foam rubber donut to go on the bottom of each inductor:
Then I wrapped two or three wire ties around each inductor to form multiple plastic mounting brackets:
Foam rubber donut goes on next:
And bolts to the 1/2 or 5/8" thick xover board with #8 x 3/4" brass screws:
The finished xover mounts on the back of the speaker behind the tweemid. It is mounted with 4 screws and is removable for parts swapping:
No thread would be complete without a few finished speaker squigglies:
I normalized the horizontal polars to the 0H 0V.frd curve so that I could see the overall consistency. Looks really good:
Here are the verticals. I only did plus (above) or minus (below) 15 degrees. The vertical lobe points down somewhat, which works out well with my 6 degree baffle tilt. No difference in sound between standing or sitting positions:
PE, HD, Menards; Most hardware stores carry those.
I've tried them before as well, but I was unhappy with the mounted coil being off the surface too far. The foam donut Bill employed fixes that problem. I think they'd be better to use if the mounting tab/hole was position upside down from how it is.
Neu's Hardware in Menomonee Falls, WI. They also have these screw mount types, in the 8" length only, at my local Menards. I mount them "backwards" and then the 1/4" foam rubber (available at Michaels or Hobby Lobby) fills in the gap on the bottom. Seems to work quite well. But time will tell. Have not tested them on a 300 mile road trip yet, which will be the true test of durability.
Forgot to mention, the solder tab lugs shown in the pictures are from Mendalson's, downtown Dayton, Ohio. They accept standard push on type connectors or solder. I can mount them in singles to create two solder joints, or use two to make a 4 solder joint. They are non-magnet (I think they are tin plated copper) and very cheap. I picked up 200 of them last year and only put a small dent in Mendalson's supply. Thanks to Eric for the recommendation. Mendalson's is now a regular stop for me on my way to MWAF. Even if I can't find what I am looking for, I always enjoy the ride up and down the huge freight elevator (3rd floor, electronics).
Must be the big 5-5/8" radius. I also measured this same tweemid driver horizontally 1) on a large IEC test baffle, 2) on a standard sized 8 x 13.5" baffle, and 3) on a 17" diameter full 360 degree sphere. I have tons of data that I am currently sifting through and comparing. Very interesting stuff, to say the least.
Finally got around to painting today. Here are a few pics after the 1st coat of primer. I am using an oil based primer, thinned slightly with minerals spirits. Using my "state of the art" HF spray gun with 1.8mm nozzle parts installed. Preparation prior to painting was the new bondo filler recommended by Brad, then block and hand sanding 120, 220, and then 320 grit prior to painting. I will be sanding with 500 or 600 between primer coats. I think 3 primer coats, with 24 hours drying between coats and sanding, should get me ready for the final high gloss enamel top coats. I will be spraying 2 or 3 coats of high gloss enamel on top of the primer and that will be it. I will not be spraying any clear coats on top of the enamel.
Here is the tower cab, ready for primer coat 1:
After 1 coat of primer:
Here is my temporary work bench:
Here is the donut, prior to painting:
Here are a few donut pics, after 1 coat of primer. I snapped these with the primer still wet, which gives them that high gloss look. Starting to look a little bit like focal eggs:
Here is what the donut looks like after the primer is dry:
Here is the crossover box, after 1 coat of primer:
Here is a picture of all the parts, after 1 coat. From left to right:
I was wondering if I could get some color suggestions. It will take me a while to finish the primer coats in prep for the final top coats. Rust-o-leum high gloss enamel is available in the following colors for about $9/quart at my local stores. I was thinking high gloss sunrise red for the donuts (same color as Linehoppers), then high gloss white for the crossovers, then high gloss leather brown for the shoes, and, finally, high gloss black for the towers. What do you think?
7715 High gloss aluminum
7792 High gloss white
7779 High gloss black (used on Linehopper feet)
7747 High gloss sunburst yellow
7765 High gloss regal red
7762 High gloss sunrise red (used on Linehopper speakers)
I think your color choices are solid, but John is correct in that glossy and dark colors ultimately mean more work. By the way the center flutes really add something to the visuals, well done.
Comments
To perform the Wolf test, I made a separate set of FRD's with the TweeMids flipped 180 degrees. The model is virtually identical, except for a slight peak at 2kHz on the flipped version. I have not ordered parts yet, so I have not listened to see if this makes a difference.
I picked up a carbide tipped 3/8" round nose bit at Menards and cut three 17" long, decorative flutes along the front baffle. This is similar to the three baffle flutes that Dan N. used on his Scimitar speakers, except that his flute spacing distance was much wider than mine (my spacing is 1/2" ctr-to-ctr). I used a plunge router and adjustable guide rail setup to do this.
Of course, Dan's speakers look a lot better than mine, but I am not finished yet. Wait until you see the finished speaker.
Next up: Custom base and crossover caddy.
I revised my crossover again using more accurate woofer data using Jeff B's blender program. I talked to Jeff at Indy last year and was able to clear up some of the problems that I was having trying to get the blender to work properly. And this time it actually worked!!
First off, I made sure that I checked the "ALL" mode when making my NF woofer measurement, as John suggested. Then I set up my baffle step model using a 9.625 inch wide baffle instead of the actual 8.625" width to account for the large donut above the tower. Then I merged NF and FF curves over the 500-800Hz range, where both curves are smooth and valid. I included port data in my NF measurement, as the port data affects the response just a little in the 100-200Hz area.
Then I moved the data back into XSim and converted all FRD's over to minimum phase (Hilbert) data. I then re-set the mod delays for the minimum phase files and then re-did the entire crossover. The attached new 3-pane XSim model shows final values using the blended NF/FF woofer data. Quite a bit of difference from my first model, which was based on FF woofer data only. Dropping resistors on the tweeter and mids increased from 5.1 to 8.2 ohms each, a significant increase of baffle step compensation. Good thing that I did not order parts for the first version; it would probably have sounded somewhat "thin" in the mid-bass 100-500Hz region. Thanks again to John and Jeff for the blender tips. I think I "finally" have the blender system figured out!!!
Ani, The NF woofer cone response was measured with OmniMic tip located about 1/4" from the center of the dust cap. The NF woofer port response was measured with the tip of OmniMic in the center of the port opening, pushed into the port 3/8" In this way, the mic tip was pushed half way into the 3/4" roundover flare of my port.
I added the NF port and NF woofer cone FR data in OmniMic using the "AddedCurves" feature. First, I added the
NF woofer cone into OmniMic. Then I used OmniMic's "Sum" function to add the adjusted NF woofer port response to the NF cone response. The NF woofer port response was previous adjusted down 6.8dB and resaved as a new adjusted FRD file. Once the two curves were summed together, I applied a 2.8ms delay to the port response to account for the time it takes for the port output to travel around the cabinet and up to the woofer cone.
Once I had this new merged NF woofer FRD, I loaded it into the Jeff B/Charlie L Blender program and blended it with the FF woofer curve. The result was then saved again with minimum phase data, then loaded into XSim. Once back in XSim, I extracted minimum phase for all FRD's and re-did the xover. It is an exhausting, multi-step process, but it all seems to work out.
EDIT: Forgot to mention, my FF woofer measurement was made at a distance of 1 meter, in the same position that I used for my midrange and tweeter measurements. Mic position and volume control settings were unchanged for these measurements.
Thanks. Always have to make sure I check the "All" mode and not the "Blended" mode in OmniMic when I do my NF curves. That was probably the issue. The slopes and smoothness of the two curves matched up perfectly from 500 to 800Hz this time around.
Made some more progress. This time, Doctor Diffraction gets a new pair of shoes!!
I started with a 6 degree beveled parallelogram:
Then I added two 6 degree angled rails along the two inside sidewalls:
To make the base removable, I bolted it to the bottom with four #8 x 1.5" wood screws:
I gave the base a 0.75 radius roundover all around. This decorative 10.25 x 14.25" base tips the loudspeaker back by 6 degrees. I was not attempting to time align. I simply needed to shift the center of gravity back a bit to compensate for the top heavy donut.
Next up: Crossover layout & assembly:
https://www.parts-express.com/jantzen-audio-30mh-15-awg-air-core-inductor-crossover-coil--255-436
Yes. It's a biggie.
I will put it on my bathroom scales to see how hefty (> 1lb of copper, for sure) I was going to go with a cheaper iron core type unit, but wanted to experiment with 15ga air core. DCR is .66 ohms, which is not too bad in the woofer circuit. Not cheap.
I see Madisound has the same value in 14ga with a slightly lower DCR at about the same cost. Too late. Parts already ordered. PE only had the 14ga units up to 2.5mH
https://www.madisoundspeakerstore.com/solen-14-awg-perfect-lay/solen-3.0-mh-perfect-lay-inductors-14-awg/
Two pounds of copper on my un-calibrated bathroom scales:
This will be my last update for a while. I'm going to put off the finishing part (sanding, bondo, painting, etc.) until the weather warms up in May. This will involve complete disassembly so that I can spray each speaker part in a variety of contrasting high gloss enamels.
One crossover with measurements is now complete. For mounting the inductors, I'm experimenting with a new wire tie method that uses the "mounting screw" type wire ties. First, I cut a 1/4" thick foam rubber donut to go on the bottom of each inductor:
Then I wrapped two or three wire ties around each inductor to form multiple plastic mounting brackets:
Foam rubber donut goes on next:
And bolts to the 1/2 or 5/8" thick xover board with #8 x 3/4" brass screws:
The finished xover mounts on the back of the speaker behind the tweemid. It is mounted with 4 screws and is removable for parts swapping:
No thread would be complete without a few finished speaker squigglies:
I normalized the horizontal polars to the 0H 0V.frd curve so that I could see the overall consistency. Looks really good:
Here are the verticals. I only did plus (above) or minus (below) 15 degrees. The vertical lobe points down somewhat, which works out well with my 6 degree baffle tilt. No difference in sound between standing or sitting positions:
Final, revised xover (version 12):
I've tried them before as well, but I was unhappy with the mounted coil being off the surface too far. The foam donut Bill employed fixes that problem. I think they'd be better to use if the mounting tab/hole was position upside down from how it is.
InDIYana Event Website
Finally got around to painting today. Here are a few pics after the 1st coat of primer. I am using an oil based primer, thinned slightly with minerals spirits. Using my "state of the art" HF spray gun with 1.8mm nozzle parts installed. Preparation prior to painting was the new bondo filler recommended by Brad, then block and hand sanding 120, 220, and then 320 grit prior to painting. I will be sanding with 500 or 600 between primer coats. I think 3 primer coats, with 24 hours drying between coats and sanding, should get me ready for the final high gloss enamel top coats. I will be spraying 2 or 3 coats of high gloss enamel on top of the primer and that will be it. I will not be spraying any clear coats on top of the enamel.
Here is the tower cab, ready for primer coat 1:
After 1 coat of primer:
Here is my temporary work bench:
Here is the donut, prior to painting:
Here are a few donut pics, after 1 coat of primer. I snapped these with the primer still wet, which gives them that high gloss look. Starting to look a little bit like focal eggs:
Here is what the donut looks like after the primer is dry:
Here is the crossover box, after 1 coat of primer:
Here is a picture of all the parts, after 1 coat. From left to right:
Tower shoe, Tower cab, donut, xover, donut, xover, tower cab, shoe.
I was wondering if I could get some color suggestions. It will take me a while to finish the primer coats in prep for the final top coats. Rust-o-leum high gloss enamel is available in the following colors for about $9/quart at my local stores. I was thinking high gloss sunrise red for the donuts (same color as Linehoppers), then high gloss white for the crossovers, then high gloss leather brown for the shoes, and, finally, high gloss black for the towers. What do you think?
7715 High gloss aluminum
7792 High gloss white
7779 High gloss black (used on Linehopper feet)
7747 High gloss sunburst yellow
7765 High gloss regal red
7762 High gloss sunrise red (used on Linehopper speakers)
7727 High gloss royal blue
7775 High gloss leather brown
7770 High gloss almond
7771 High gloss sand