Oh, I finally got it.
The orange polygons in the drawing are the tweeters with their lens.
So, how's your room's layout? And is there any acoustic treatment?
The orange polygons in the drawing are the tweeters with their lens.
So, how's your room's layout? And is there any acoustic treatment?
According to Haas, imaging cues are determined by the first millisecond of sound.
So the enclosure shape likely has a greater effect on imaging than the room treatment does.
On top of that, this speaker is listened to in the extreme nearfield. That has pluses and minuses. On the downside, the midrange and the tweeter need to be very very close together. On the upside, the direct sound dominates the room.
On top of all that, I have the speaker about 75cm from a window, so a great deal of the energy that would normally get reflected by the wall just flies out the window.
Effusive praise For You
Patrick, I vote you as the most amazing denizen of DIYaudio. I admire you; you seem to be able to give audio tinkering nearly full time in your life? I will have to compile your biography 🙂 and figure how you manage this.
I don't want to dissuade you from posting here but have you ever considered your own web site a la Ethan Winer (another audio demi-god of mine?). I am not aware you have a commercial product but making DIY knock-offs is an admirable pursuit too
You should count yourself lucky that you live far from me. If I were closer to you I would make a reasonable effort to stalk you, to bribe you or otherwise ingratiate myself into being able to just be an occasional visitor or guest to see the amazing creations in the "Bate cave"*. Just that is a mystery: you have built so many items, where do you keep them all???
*I am a master of puns; I'm surely not the first to have called you "Bate-man" in jest? I vote that you make this your avatar instead of the Clint Eastwood photo ("Was my speaker five-way or six-way? There was so much noise I don't remember. Do you feel lucky, punk?") The possibilities are endless -- all the better if you have a friend (either sex even) named "Robin".
sent from my tablet
Patrick, I vote you as the most amazing denizen of DIYaudio. I admire you; you seem to be able to give audio tinkering nearly full time in your life? I will have to compile your biography 🙂 and figure how you manage this.
I don't want to dissuade you from posting here but have you ever considered your own web site a la Ethan Winer (another audio demi-god of mine?). I am not aware you have a commercial product but making DIY knock-offs is an admirable pursuit too
You should count yourself lucky that you live far from me. If I were closer to you I would make a reasonable effort to stalk you, to bribe you or otherwise ingratiate myself into being able to just be an occasional visitor or guest to see the amazing creations in the "Bate cave"*. Just that is a mystery: you have built so many items, where do you keep them all???
*I am a master of puns; I'm surely not the first to have called you "Bate-man" in jest? I vote that you make this your avatar instead of the Clint Eastwood photo ("Was my speaker five-way or six-way? There was so much noise I don't remember. Do you feel lucky, punk?") The possibilities are endless -- all the better if you have a friend (either sex even) named "Robin".
sent from my tablet
Some ideas relevant to waveguides...
Disclaimer: these are just ideas, free of even the usual lackadasical Soldermizer experimentation 🙂
For one-off construction, here is a maybe super-easy idea: why not try modeling clay? This is sold at Michael's and elsewhere. Available in a choice of colors, shape as needed. I think you can bake it to "fire" it. If you know a potter, WTF, have her fire you a real one.
A variation on layered MDF: you could make a finer curve, albeit with more time and effort, by using thinner board or even Coroplast such as I'm accumulating from harvesting illegally placed advertising signs along the highways. If you know someone who's Rainman type ADHD, have him make you one of layers of newsprint with library paste. No belay that, you would probably get too much HF absorption with paper.
Hmmm...I am well on my way to making some DIY audio a grade school project 🙂
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Disclaimer: these are just ideas, free of even the usual lackadasical Soldermizer experimentation 🙂
For one-off construction, here is a maybe super-easy idea: why not try modeling clay? This is sold at Michael's and elsewhere. Available in a choice of colors, shape as needed. I think you can bake it to "fire" it. If you know a potter, WTF, have her fire you a real one.
A variation on layered MDF: you could make a finer curve, albeit with more time and effort, by using thinner board or even Coroplast such as I'm accumulating from harvesting illegally placed advertising signs along the highways. If you know someone who's Rainman type ADHD, have him make you one of layers of newsprint with library paste. No belay that, you would probably get too much HF absorption with paper.
Hmmm...I am well on my way to making some DIY audio a grade school project 🙂
sent from my tablet
J's avatar is Christian Bale, not Clint Eastwood.
"Patrick Bateman" is a pseudonym based on a psychotic character in American Psycho, a sadistic, cannibalistic murderer prone to rape, torture and necrophilia, to whom everything is a commodity, including people.
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But he's also an insane person who's obsessed with audio (Note he owns Kef speakers, some nice stereo equipment, and he can't stop talking and writing about music.)
So except for the parts where he's hacking up people with an axe, I think it's an excellent pseudonym!
Effusive praise For You
Patrick, I vote you as the most amazing denizen of DIYaudio. I admire you; you seem to be able to give audio tinkering nearly full time in your life? I will have to compile your biography 🙂 and figure how you manage this.
I don't want to dissuade you from posting here but have you ever considered your own web site a la Ethan Winer (another audio demi-god of mine?). I am not aware you have a commercial product but making DIY knock-offs is an admirable pursuit too
You should count yourself lucky that you live far from me. If I were closer to you I would make a reasonable effort to stalk you, to bribe you or otherwise ingratiate myself into being able to just be an occasional visitor or guest to see the amazing creations in the "Bate cave"*. Just that is a mystery: you have built so many items, where do you keep them all???
*I am a master of puns; I'm surely not the first to have called you "Bate-man" in jest? I vote that you make this your avatar instead of the Clint Eastwood photo ("Was my speaker five-way or six-way? There was so much noise I don't remember. Do you feel lucky, punk?") The possibilities are endless -- all the better if you have a friend (either sex even) named "Robin".
sent from my tablet
I appreciate the kind words! Hopefully it will work well enough to earn it.
But first, I have some work to do refining this.
Here's a pic of what the midrange taps looked like a few days ago.
When I went from four midrange taps to two, the imaging improved dramatically. I'm not talking about a subtle improvement in focus. I'm talking about a soundstage that went from being about four feet wide, to a soundstage that appears to extend beyond the walls of the room. Night and day.
The reason for the improvement is simple. With four midrange taps, the sound from the far side of the cone is nearly one whole wavelength out-of-phase with the sound from the near side of the cone. Reducing the taps to two makes the taps equidistant.
An externally hosted image should be here but it was not working when we last tested it.
Unfortunately, going from four to two midrange taps creates a new problem. It rolls off the midrange sooner. This is because the tuning frequency of the taps gets lower as the size gets smaller. So the solution is simple; I have to increase the size of the two remaining taps.
Here's a pic of some line arrays from Nexo. They use an 8" B&C driver, and my midrange taps will start to look a lot like the Nexo phase plug once I'm finished enlarging them.
Here's a pic of the Nexo phase plug from the back side, note how it minimizes the volume of air in the coupling chamber. This is by design, it extends the high frequencies. The more air that is in the coupling chamber, the more the highs are rolled off.
The painting on the wall is by Robert Longo. I thought that was a nice choice; not as glaringly "80s" as something by Patrick Nagel, but not really tasteful either. Back when I was an art major I would routinely bite the style of both those artists. Saw Robert Longo's exhibit at the LA County Museum of art in 1989. I was 17.
An externally hosted image should be here but it was not working when we last tested it.
The speaker in the corner is a Kef Reference 3
I've used modeling clay to smooth out the throats of compression drivers. It is definitely better than nothing, but the problem I run into with clay is that it's hard to make it symmetrical. And if it's not symmetrical, the response from the left compression driver will be different than from the right.
But, yes, it will definitely get you 90% of the way to the goal.
One alternative to 3D printing may be a tree shaped radial burr. I have one of these in my drill bit collection. I bought it from Boeing Surplus in Renton WA. I had no idea how expensive these are - about $50-$100. (I paid about five bucks iirc.) Boeing Surplus is amazing... But that's a different discussion.
Anyways, if the diameter of the tree burr is the size of your tweeter, then the size will basically be correct for a SAW lens.
In the pic above, I've illustrated this using a 1 1/8" burr that's for sale on eBay right now.
Large SGS Carbide Burr Rotary File American Made | eBay
^^ Here's the link. If the auction is expired, just look for "large SGS carbide burr"
Burrs | MSCDirect.com
Here's a smaller one, from the same company.
The size of the burr that you use will really depend on your tweeter. For a 1" compression driver, you're going to want a 1" burr.
An externally hosted image should be here but it was not working when we last tested it.
For a 1" dome tweeter, you'll want one that's a little bit larger, because a 1" tweeter has a surround that makes the exit a little bit larger than 1". 1 1/8" should work fine.
Would this work for a super simple build?
I am fascinated by ... too much! Last week I was going to build an ambiophonics box. I still am building an incipient subwoofer. For the moment, I would like to try my hand at building a full range version of Patrick's "horn." Do you think it would work? i have on hand a few spare generic full rangers (similar to but not Bose 901 drivers). Would some type of diffuser be needed? I do in fact have a few tweeters too but that is too advanced for me right now. I also have in mind an office PC set-up. Currently its audio system is a Bose wave radio which works well ("loud") but lacks that certain panache a DIY creation would have, even if I made it out of Coroplast and glue 🙂
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I am fascinated by ... too much! Last week I was going to build an ambiophonics box. I still am building an incipient subwoofer. For the moment, I would like to try my hand at building a full range version of Patrick's "horn." Do you think it would work? i have on hand a few spare generic full rangers (similar to but not Bose 901 drivers). Would some type of diffuser be needed? I do in fact have a few tweeters too but that is too advanced for me right now. I also have in mind an office PC set-up. Currently its audio system is a Bose wave radio which works well ("loud") but lacks that certain panache a DIY creation would have, even if I made it out of Coroplast and glue 🙂
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The two way that's documented here can go full range if you use an 8" woofer with a lower FS and make it a vented box. Basically I was interested in very high output so I used a prosound 8".
You could also do this as a three way.
In my setup, I am sitting on the subwoofer so the frequencies break down like this:
sub : 20hz - 160
woofer : 160hz - ?
tweeter : ? - 20khz
Here's Soldermizer sound bar rev 0:
This is a beta version of my project. As you can see, the enclosure is a pair of Cat litter boxes. One dimension of each box is very close to 25 cm, about half of the separation that Bateman design uses. If you care, each box is about 20x25x29 cm. The driver is a brand x ordered via AliExpress. I was going to try these as Bose 901 drivers but don't need them after all. The odd white rice looking things on the driver are, in fact, rice. In a separate thread I showed my lazy man's version of Enabl dots 🙂
Each box is stuffed with some old t-shirts. Lacking the specs for the driver (I am dubious it will reach the labeled 50 watts.) I can't do any modeling so why not just use on hand materials, and the most forgiving box (sealed)? "Sealed" remains to be tested once the caulk dries. For now, just caulk will ("may") hold each driver in place. I will play (with) them once dried. Option: glue together to make the 50 cm wide "sound bar".
Today's wis-dumb: For most audio equipment, a double blind test is good. But for my builds, a "double deaf" test might be better
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This is a beta version of my project. As you can see, the enclosure is a pair of Cat litter boxes. One dimension of each box is very close to 25 cm, about half of the separation that Bateman design uses. If you care, each box is about 20x25x29 cm. The driver is a brand x ordered via AliExpress. I was going to try these as Bose 901 drivers but don't need them after all. The odd white rice looking things on the driver are, in fact, rice. In a separate thread I showed my lazy man's version of Enabl dots 🙂
Each box is stuffed with some old t-shirts. Lacking the specs for the driver (I am dubious it will reach the labeled 50 watts.) I can't do any modeling so why not just use on hand materials, and the most forgiving box (sealed)? "Sealed" remains to be tested once the caulk dries. For now, just caulk will ("may") hold each driver in place. I will play (with) them once dried. Option: glue together to make the 50 cm wide "sound bar".
Today's wis-dumb: For most audio equipment, a double blind test is good. But for my builds, a "double deaf" test might be better
Sent from Tapatalk app on my Android tablet.
An unexpected benefit of the Tidy Cats box is ...
The speaker is mounted on a "double thick baffle" :there are two layers of cardboard there Whee! Actually, they are a quite sturdy box, having to contain 23 Lb. of product as they do.
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The speaker is mounted on a "double thick baffle" :there are two layers of cardboard there Whee! Actually, they are a quite sturdy box, having to contain 23 Lb. of product as they do.
Sent from Tapatalk app on my Android tablet.
Back to the drawing board...
Having killed 2 of 3 drivers, it occurs to me that I maybe should get a better match between an amp that can put 440 watts into eight ohms, and a cheap fullrange that is rated -- probably delusionally -- for fifty watts. 🙁
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Having killed 2 of 3 drivers, it occurs to me that I maybe should get a better match between an amp that can put 440 watts into eight ohms, and a cheap fullrange that is rated -- probably delusionally -- for fifty watts. 🙁
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Perhaps it should occur to you that when said speakers sound like cat doo doo you should not push them into the kill zone, but as you wrote, "for my builds, a "double deaf" test might be better" so have at it
You speak with wisdom 🙂
I've given up on the cheapo drivers. In fact, tossed out the single unkilled one.
I have on hand from a months-ago project (bipoles? PVC tubing? Hell, I forget, check my posts if you really give a darn) ... a pair of almost-fits 5 1/4 car 3-ways. I've jammed them them into the pre-existing holes and waiting for the caulk to dry. I will try and be gentler with the volume control next time
Sent from Tapatalk app on my Android tablet.
I've given up on the cheapo drivers. In fact, tossed out the single unkilled one.
I have on hand from a months-ago project (bipoles? PVC tubing? Hell, I forget, check my posts if you really give a darn) ... a pair of almost-fits 5 1/4 car 3-ways. I've jammed them them into the pre-existing holes and waiting for the caulk to dry. I will try and be gentler with the volume control next time
Sent from Tapatalk app on my Android tablet.
The enclosures, in addition to being cheap, still have the kitty litter labels. This helps prepare the hapless listener to endure sound that will probably sound like "s--t".
A design feature (yeah, right) is that a trace of gravel remains in each box. This makes maraca and other rattle type percussion sound all the more authentic. Excellent for Latin Jazz and similar.
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A design feature (yeah, right) is that a trace of gravel remains in each box. This makes maraca and other rattle type percussion sound all the more authentic. Excellent for Latin Jazz and similar.
Sent from Tapatalk app on my Android tablet.
In my measurements, I was seeing substantial evidence of diffraction. The measurement above shows the unfiltered response of the woofer, and the filtered response of the compression driver. There are diffraction dips at 1700hz, 3000hz, 9000hz and 15,000hz.
Here's a diffraction measurement that Siegfried Linkwitz did off of a disc, from here: Diffraction from baffle edges
You can see the dips I'm getting are similar to what Linkwitz illustrated.
Here's a measurement I did of my QSC waveguides, using a similar compression driver. The waveguide is substantially smoother.
So here's something about the B&O lens which is worth improving; diffraction is an issue. Go figure, it looks like B&O knows this, and a member of the Diyma forum showed me this article. Unfortunately he showed it to me about a week after I started my project 🙂
B&O Tech: Curves are Better than Corners earfluff and eyecandy
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