I've also been looking at my next project.
I'm currently running single Seas L26 10" woofers (sealed) and they need the support of a subwoofer to fill out the low end (F3 42Hz - room gain doesn't help).
Like you, I am entertaining large mains speakers that do not need a subwoofer. I was liking the low distortion with the WO24-P (use a pair) but would need to port them to get the low frequency extension. Box size doesn't worry me.
I'm still wondering whether a larger 12" or 15" driver would be better here, assuming I can pair with capable 6.5" midranges.
Again - it comes down to how audible bass distortion is. I know of equal loudness curves for the fundamental, but I don't know how audible 3rd order distortion at bass frequencies to be able to choose drivers.
I'm currently running single Seas L26 10" woofers (sealed) and they need the support of a subwoofer to fill out the low end (F3 42Hz - room gain doesn't help).
Like you, I am entertaining large mains speakers that do not need a subwoofer. I was liking the low distortion with the WO24-P (use a pair) but would need to port them to get the low frequency extension. Box size doesn't worry me.
I'm still wondering whether a larger 12" or 15" driver would be better here, assuming I can pair with capable 6.5" midranges.
Again - it comes down to how audible bass distortion is. I know of equal loudness curves for the fundamental, but I don't know how audible 3rd order distortion at bass frequencies to be able to choose drivers.
I've made my decision. I'm going with the Scan-Speak 28W, with 2 per box. I rebuilt another box that was smaller and played with the tuning. The Scan-Speak, despite pushing a lot more volume need a smaller box and they are very picky about port tuning. With the correct tuning, they smoothed out and still hit lower. I was also able to address much of my chuffing problems through a few minor changes. For the final speaker, the ports will be custom turned from aluminum tubing, and the flares custom made on my mill, so I cam make them an odd size if I want. That being said, if you are at all price conscious, the Satori drivers are a no brainier. I can't say enough about them. I'll sell the Satori drivers off and keep the 13" scan-speak's for a future project.
In other words if the satori could be done with one driver in 2 cubic feet then they might be alright. What kind of conditions would you think they will work?
Sounds nice. Do you think a large amount of wool fill could have reduced the amount of cubic volume. so maybe 4.4 cubic volume could have been reduced to 3.4 will wool. Just wondering how much experimentation you did with the satori woofers. Thanks.
HI mp006ltk,
I am designing my own speakers with 32w 8 ohms.
I am in the same line of thinking for digital filters and dsp.
The first big 3 ways I built was with big 15 inches like alnico, from saba, a real monsters that would play clean bass down 30 and up 800s.
I first built it in MDF and the sound was dead as you experienced.
I was going to throw the whole project in the garbage. Then I purchased furniture grade (not as good as flooring grade, has some gaps and holes) oak 3/4 plywood.
The trick was to load it to make is as heavy as possible and the sound was full, a little coloration but at least it was lively, fulfilling.
Maybe this is what you are experiencing there.
if you look at the 32W4, the THD 3rd rise at 600hz, however it then goes down again and only becomes objectionable in the 1100hz.
According to this data a xo in 455hz 2n order should be ideal and with proper -4db at the XO point, the THD at 600hz is relatively lower than the mid-range and out of the audibility point.
If you are doing a mega super no thd design, then the THD at 600hz becomes objectionable for coloration from 2n order etc, then the xo point (2nd order), can be ideally 260hz...
Did you measured the noise with the microphone, it will show you if you failed at the box and securing the driver, etc.
In the measuring software you look at the THD , they should be as stated in hificompass, but then look at the noise parameter, this could cause a bad sound.
I am designing my own speakers with 32w 8 ohms.
I am in the same line of thinking for digital filters and dsp.
The first big 3 ways I built was with big 15 inches like alnico, from saba, a real monsters that would play clean bass down 30 and up 800s.
I first built it in MDF and the sound was dead as you experienced.
I was going to throw the whole project in the garbage. Then I purchased furniture grade (not as good as flooring grade, has some gaps and holes) oak 3/4 plywood.
The trick was to load it to make is as heavy as possible and the sound was full, a little coloration but at least it was lively, fulfilling.
Maybe this is what you are experiencing there.
if you look at the 32W4, the THD 3rd rise at 600hz, however it then goes down again and only becomes objectionable in the 1100hz.
According to this data a xo in 455hz 2n order should be ideal and with proper -4db at the XO point, the THD at 600hz is relatively lower than the mid-range and out of the audibility point.
If you are doing a mega super no thd design, then the THD at 600hz becomes objectionable for coloration from 2n order etc, then the xo point (2nd order), can be ideally 260hz...
Did you measured the noise with the microphone, it will show you if you failed at the box and securing the driver, etc.
In the measuring software you look at the THD , they should be as stated in hificompass, but then look at the noise parameter, this could cause a bad sound.
I wasn't running the 32w that high. I'm sure there was "some"response at that level, but I built a crossover to drop the rising response and roll it off much lower. It's not like it's silent at 400-1000 hz but 2nd order around 200-250 gave me a real world response. I would say crossover should be closer to 100-150 2nd order. I guess you could use a steeper slope, but I havn'e seen many 4th order W/M crossovers.
My final design will likely be corian, phenolic, or aluminum. I have to experiement with the plastics to make sure temp swings doesn't cause them to expand/contract, irregularly and split their glue lines. My VMC can hangle 40"x16" of travel, but my router can handle almost 48"x96", so If I choose aluminum, I'm going to be sending parts out becasue of the 16" Y axis. I'm leaning to corian since it cuts like butter.
My final design will likely be corian, phenolic, or aluminum. I have to experiement with the plastics to make sure temp swings doesn't cause them to expand/contract, irregularly and split their glue lines. My VMC can hangle 40"x16" of travel, but my router can handle almost 48"x96", so If I choose aluminum, I'm going to be sending parts out becasue of the 16" Y axis. I'm leaning to corian since it cuts like butter.
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There is no way I can XO at 120 with passive parts or 3, 4 th order.
the calculated -12db slope (which suits my purpose) requires so far 7.5mh of inductor (iron core i have) and 180uf of caps.
if I double the inductance let say, ill have to drop the mid sensitivity (18m from SS too) and have substantial XO cost, which is out of question.
So I am intrigued and I should do a good listening test...
calculated delay is 22ms at 30hz, port (4'') tuned to 24.5.
at least a 4ft3 enclosure
the calculated -12db slope (which suits my purpose) requires so far 7.5mh of inductor (iron core i have) and 180uf of caps.
if I double the inductance let say, ill have to drop the mid sensitivity (18m from SS too) and have substantial XO cost, which is out of question.
So I am intrigued and I should do a good listening test...
calculated delay is 22ms at 30hz, port (4'') tuned to 24.5.
at least a 4ft3 enclosure
I heard some people who succeed with active xos, multiple amps etc.
It is a sub but not as big as my REL were, and I measured in the whole house almost flat to 22 hz but I will not say what I though about the sound.
if you look there is a new 32w with bigger magnets which are 100% sub.
At the limit the 32w 8 ohm could be crossed higher, the 4 ohm is truly ported etc.
If my experience of drivers with dedicated class AB 500watt + is not as good as with 20 watts, high sensitivity, I will never use any dsp or active filters, to me this destroy everything that I have build my sound system upon.
It is a sub but not as big as my REL were, and I measured in the whole house almost flat to 22 hz but I will not say what I though about the sound.
if you look there is a new 32w with bigger magnets which are 100% sub.
At the limit the 32w 8 ohm could be crossed higher, the 4 ohm is truly ported etc.
If my experience of drivers with dedicated class AB 500watt + is not as good as with 20 watts, high sensitivity, I will never use any dsp or active filters, to me this destroy everything that I have build my sound system upon.
mp006 , I am actually building the box with a second underneath box loaded with sand and resonance of 50 hertz, this is in order to delete standing waves due to the port in the box at 24 hz, it deletes the resonances at 50 and 75 hz. it also stabilize the box which is 44 inches tall,
I will use a lot of cotton towels on the walls over acoustic gum finish, glued with silica compound (very costly but i have a big supply!),
I use a standard plastic port which I will cover with silica compound to make more sturdy and remove any vibrations into heat.
I will support the back of the woofer with pine wood and brace the box with rounded edges pine, and glued again with silica compound.
I will also use some rolled paper with cotton towels to make bass traps, 2 inside each box, and 3 pounds of 3oz wool, that should do it!
I used 2 pounds of this wool to get better sound from my grand piano with closed cover, it worked very very well, so I can imagine 3 pounds in a 4ft3 box can do wonders for higher frequencies, it is going to be great and 'natural'
I will use a lot of cotton towels on the walls over acoustic gum finish, glued with silica compound (very costly but i have a big supply!),
I use a standard plastic port which I will cover with silica compound to make more sturdy and remove any vibrations into heat.
I will support the back of the woofer with pine wood and brace the box with rounded edges pine, and glued again with silica compound.
I will also use some rolled paper with cotton towels to make bass traps, 2 inside each box, and 3 pounds of 3oz wool, that should do it!
I used 2 pounds of this wool to get better sound from my grand piano with closed cover, it worked very very well, so I can imagine 3 pounds in a 4ft3 box can do wonders for higher frequencies, it is going to be great and 'natural'
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Quote: you can hear audible distortion over 150hz. Scan-Speak never marketed this as a woofer, so this application is off label, but don’t think that this is functional in a 3 way with passive crossovers.
This will be certainly interesting as I test my 8 ohm version, I chose especially for the ability to play over 500hz without distortion with a 2nd order filter.
So far it will be in a separate box, approximatively 4ft3 reflex 4 inch tuned to 24.5, this is all speculative so far.
I plan to have 4 corner holes with cotton damping in them connecting the 4ft3 to an under box with the bottom filled with sand.
The under box would be tuned with the holes to be a 50hz resonator to dissipate the 2nd harmonics and some 3rd too caused by the port and bass delay of 26 ms at 25hz.
other than that I plan on using (per box) 3 pounds of wool, 2 pounds of cotton and 0.3 pounds of thick paper fibers to make inside diffusers traps.
This will be certainly interesting as I test my 8 ohm version, I chose especially for the ability to play over 500hz without distortion with a 2nd order filter.
So far it will be in a separate box, approximatively 4ft3 reflex 4 inch tuned to 24.5, this is all speculative so far.
I plan to have 4 corner holes with cotton damping in them connecting the 4ft3 to an under box with the bottom filled with sand.
The under box would be tuned with the holes to be a 50hz resonator to dissipate the 2nd harmonics and some 3rd too caused by the port and bass delay of 26 ms at 25hz.
other than that I plan on using (per box) 3 pounds of wool, 2 pounds of cotton and 0.3 pounds of thick paper fibers to make inside diffusers traps.
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sorry for the images sideways
BTW, The material is 18mm baltic birch with a layer of thick dynamat on the inside. There are not mechanical fasteners in the wood and it's held together with normal wood glue and some polyurethane adhesive. The internals are reasonably well braced. The bass section extends into the top part of the cabinet for additional volume. The finish is polyester primer, followed by House of Kolor white DTS primer, followed by a custom shade of white basecoat, and 3 coats of House of Kolor Sno White pearl mixed at 33%. Then 4 coats of clear. The aluminum wash machined on my Haas VMC with Pierson vacuum chucks. and the port was sent out to a friend with a VERY expensive DMG Mori turning center. All the wood was cut on a heavy 4x8 router with centroid control and yaskawa servos.
BTW, The material is 18mm baltic birch with a layer of thick dynamat on the inside. There are not mechanical fasteners in the wood and it's held together with normal wood glue and some polyurethane adhesive. The internals are reasonably well braced. The bass section extends into the top part of the cabinet for additional volume. The finish is polyester primer, followed by House of Kolor white DTS primer, followed by a custom shade of white basecoat, and 3 coats of House of Kolor Sno White pearl mixed at 33%. Then 4 coats of clear. The aluminum wash machined on my Haas VMC with Pierson vacuum chucks. and the port was sent out to a friend with a VERY expensive DMG Mori turning center. All the wood was cut on a heavy 4x8 router with centroid control and yaskawa servos.
The rear photo shows two ports, one small diameter near the top and one large diameter near the bottom.
Is the top port used for the midrange and the bottom port used for the woofers.... i.e. a ported midrange? Most 3-way designs use a sealed midrange as one of the main benefits.
Does the top "hole" serve a different use?
Excellent selection of drivers.