I'd also like to build an XKi with the PA130-8 driver, but I'm planning to use 12mm baltic birch. I started with the drawing you did many many pages back, and adjusted the dimensions to account for the thickness of the the wood. Does this look like it'll work (larger image attached)?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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it probably would help to use melamine pads in the front chamber (X can make suggestions) - my Baltic birch PA130 XKi have some coloration that's a bit too noticeable - I fried one driver so they've sat for awhile.
although off topic - one of the clearest K setups I briefly tried was K15 with an Altec 421, a radial horn 30" wide by ~7" tall by SFW rolling in ~700Hz which was almost as large as the Community BRH and a ring radiator - much clearer than any (direct radiator) FR I've ever heard with regards to vocals using a Nick Cave CD as test. (not sure how it sounded on other music - lol)
although off topic - one of the clearest K setups I briefly tried was K15 with an Altec 421, a radial horn 30" wide by ~7" tall by SFW rolling in ~700Hz which was almost as large as the Community BRH and a ring radiator - much clearer than any (direct radiator) FR I've ever heard with regards to vocals using a Nick Cave CD as test. (not sure how it sounded on other music - lol)
Hi xrk,
I have read this thread and seen where you recommend wool felt be installed, but just to be sure I wanted to post a picture and get your feedback - in the picture below there are areas incased in red. Those are the areas I need to install wool felt aren't they?
Also, I have done a slightly different shaped k-aperture than the usual - I read earlier that the wider the hole at the bottom the more high frequencies get through at the expense of dispersion, and the wider the slot at the top the more bass quantity you get at the expense of bass extension, so I changed the curve slightly.
Additionally, in case I want to add a tweeter later ala Xkiclops, I have left enough vertical space between the top of the aperture and the top of the front baffle, so a tweeter can fit. I hope the aperture is still high enough.
Finally, I am planning on rounding over the inside of the aperture curves, like I have done on the outer edges of the front baffle, in my mind, that will aid with dispersion.
Does this all look like a terrible idea to you?
Finally, I have ordered some 10mm accoustic foam to line the cabinets with. You mentioned earlier that it's good to also line the back side of the front baffle with felt. I also have 1mm felt lying around - should I use the 10mm felt or the 1mm felt for the back side of the k-aperture front baffle?
I have read this thread and seen where you recommend wool felt be installed, but just to be sure I wanted to post a picture and get your feedback - in the picture below there are areas incased in red. Those are the areas I need to install wool felt aren't they?
Also, I have done a slightly different shaped k-aperture than the usual - I read earlier that the wider the hole at the bottom the more high frequencies get through at the expense of dispersion, and the wider the slot at the top the more bass quantity you get at the expense of bass extension, so I changed the curve slightly.
Additionally, in case I want to add a tweeter later ala Xkiclops, I have left enough vertical space between the top of the aperture and the top of the front baffle, so a tweeter can fit. I hope the aperture is still high enough.
Finally, I am planning on rounding over the inside of the aperture curves, like I have done on the outer edges of the front baffle, in my mind, that will aid with dispersion.
Does this all look like a terrible idea to you?
Finally, I have ordered some 10mm accoustic foam to line the cabinets with. You mentioned earlier that it's good to also line the back side of the front baffle with felt. I also have 1mm felt lying around - should I use the 10mm felt or the 1mm felt for the back side of the k-aperture front baffle?
Yes, the areas you outlined are are correct. Don’t block the vent opening. You can get use the melamine foam pads - I have had good luck with them. They are same as professional sound abatement foam. Very fine pore size and totally breathable so they dampen sound but take up very little volume.
It’s fine what you did with aperture. Yes, line the inside of the aperture and also the sidewalls if the front chamber. I had good luck just flying a later of paper faced foam core to the inside of the front aperture.
It’s fine what you did with aperture. Yes, line the inside of the aperture and also the sidewalls if the front chamber. I had good luck just flying a later of paper faced foam core to the inside of the front aperture.
I would use the melamine sponges (scrubber pads) over all other materials. It is that good.
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fwiw - here's a K-aperture I used on an 8 inch speaker (shown with a Delta Pro8a but sounded decent with FE206EN on opera recordings) - I don't think this extended the low end at all as the vent was above the driver and not at the top of the cabinet. A tight aperture on a "small" K18 sounded pretty good but had to have the starting gap at 1.2" width or transients sounded "throttled"
Hi xrk,
My set is almost ready. I've been looking forward to doing a post with some photos and explanation of what I think of them for a while now.
But it's been a bit of a saga really - I had the boxes constructed, filled, primed, painted and clear coated ready to a decent standard two months ago. They had a nick here and there and they weren't perfect, but I was happy enough with them.
To finish them I went to my parents place to polish them, as my dad has a good setup, but we polished through the clear coat into the paint.
My Dad then offered to finish them for me, and it's been two months since then. He's a perfectionist - he rubbed back all of the paint and has repainted them several times since I gave them to him. Every time he painted or clear coated them something has gong wrong! Either it bubbles, or it's too thin, or the paint won't cure even after a week, or something else weird and inextricable happens.
I have faith he will finish them in the next two weeks. After that I'll do a bit of a write up. The short of it is when I had them test fitted together I was very happy with them, so I will be even happier with them once they are complete!
My set is almost ready. I've been looking forward to doing a post with some photos and explanation of what I think of them for a while now.
But it's been a bit of a saga really - I had the boxes constructed, filled, primed, painted and clear coated ready to a decent standard two months ago. They had a nick here and there and they weren't perfect, but I was happy enough with them.
To finish them I went to my parents place to polish them, as my dad has a good setup, but we polished through the clear coat into the paint.
My Dad then offered to finish them for me, and it's been two months since then. He's a perfectionist - he rubbed back all of the paint and has repainted them several times since I gave them to him. Every time he painted or clear coated them something has gong wrong! Either it bubbles, or it's too thin, or the paint won't cure even after a week, or something else weird and inextricable happens.
I have faith he will finish them in the next two weeks. After that I'll do a bit of a write up. The short of it is when I had them test fitted together I was very happy with them, so I will be even happier with them once they are complete!
Hi Thermcul,
Ok, hope you have some wood left once it’s been refinished 24 times!
Glad that the test listen you had sounded good. Sanded and hand rubbed boiled linseed oil works very well. That’s how I did my last speakers and really like that.
Clear satin finish lacquer on mainbody and black Duratex on K aperture is also very nice.
Ok, hope you have some wood left once it’s been refinished 24 times!
Glad that the test listen you had sounded good. Sanded and hand rubbed boiled linseed oil works very well. That’s how I did my last speakers and really like that.
Clear satin finish lacquer on mainbody and black Duratex on K aperture is also very nice.
I'm not at a woodworking skill enough to do clear finishes on these boxes - I've done simple butt joints, and used copious amounts of filler!
From the beginning I planned on painting them white, off-white or cream.
I initially painted them cream, but Dad gave up on the paint I had used and has painted them plain white now.
Plain white is far more boring, but at least it will suit my computer desk better.
Painting the boxes will cover a multitude of sins! They will look much nicer as a result.
From the beginning I planned on painting them white, off-white or cream.
I initially painted them cream, but Dad gave up on the paint I had used and has painted them plain white now.
Plain white is far more boring, but at least it will suit my computer desk better.
Painting the boxes will cover a multitude of sins! They will look much nicer as a result.
r:tweeter = good question - probably a K-tube and DE250 or cheap knockoff - dunno if the inexpensive PRV is comfortable low enough to deal with Delta10a (?)
- can't remember which 2nd order values I tried for Delta10a's lowpass- do you think 1K8 is doable ? - I'm hoping to get
a powerful K which can play pretty loud and nice with slapped acoustic bass and drums
- can't remember which 2nd order values I tried for Delta10a's lowpass- do you think 1K8 is doable ? - I'm hoping to get
a powerful K which can play pretty loud and nice with slapped acoustic bass and drums
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If you think 5m450 would play with minimal "artifacts" and dips/peaks then I might give one a try as want to know what it does on a horn. Delta 10a played in the open with pink noise and no crossover sounds "awful" - but its cheap, good thermal ability and reasonably strong. I've seen one of its cousins used in Econowave builds.
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I have not put a 5MR450NDY in a K as a top yet - been meaning to try it out and could be a pretty fun 2 hour foam core project. The simplest thing to do is put it in a rear sealed chamber and open face for zero artifacts as it is quite neutral. I have it on Hypercube rear chamber and it sounds quite nice. I will have to dig up my miniDSP gear to play with the XO's though.
