No, I look for a household object like a plate or bowl that has the same dia as the required cutout. Then I use an xacto to cut thru.
I used to go to the woodworking shows and the inventer of the Dubby Miter Sled would do a neat demo. He would cut the miters on all pieces and lay them out over masking tape. Then he would just fold them into the rectangle to show that the miters were accurate. It seems that this technique might have some application with holding pieces in alignment for assy of these tiny K-boxes.
EddieT: Back somewhere in the Terry Cain's Bib thread a professional woodworker was talking about that technique for building a set of speakers in under an hour. 45 degree miter, tape the corners, apply glue to the edges, and roll into an almost complete speaker.
GYChang: You inspired me to buy the Bofu's. My plan was to build Woden Half Changs with the PE 3/4" helper tweeter as you did. Yet to be built.....
GYChang: You inspired me to buy the Bofu's. My plan was to build Woden Half Changs with the PE 3/4" helper tweeter as you did. Yet to be built.....
have used the masking tape technique on miters joints many times and it works quite well
That combo is excellent, will look forward to your build. 4.5" Pioneer A11 speakers in several different cabinets are also very good and is under rated but I digress...
Initial measurement of the Beta 8cx XKi shows bass extension is good and distortion is very low. There is a large dip at 1kHz though - I suspect it is the port resonance cancellation. The 1kHz corresponds to approximately the fundamental frequency of a 13.5 in long vent - approximately the acoustical length of this design if you account for losses of a 90deg turn. This means that the vent will have to be reduced in CSA and length shortened to bring the dip above the XO freq. The PRV D280Ti needs to be crossed at about 1.2kHz so this is a problem for now.
However, it shows that the design achieves pretty good bass extension and cone excursion control and fairly uniform response over the effective bandwidth.
Next step is to add CD to the coaxial and see how it sounds, 1KHz dip notwithstanding. Probably will require surgery to go in and reduce port length.
However, it shows that the design achieves pretty good bass extension and cone excursion control and fairly uniform response over the effective bandwidth.
Next step is to add CD to the coaxial and see how it sounds, 1KHz dip notwithstanding. Probably will require surgery to go in and reduce port length.
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I'll probably try ~2K5 crossover - hey, Bob Crites fairly recently did a first order with Selenium D220Ti - his highpass cap was 0.44uF due to autoformer attenuation of the HF driver. https://community.klipsch.com/index.php?/topic/146074-eminence-beta-8-cx-8-inch-coaxial-driver/
it'll be interesting how you tackle the 1KHz vent trap dip and also how much power this little booger can put out without a lot of cone jumping antics.
it'll be interesting how you tackle the 1KHz vent trap dip and also how much power this little booger can put out without a lot of cone jumping antics.
here (if the translate link works) is a more aggressive passive crossover for Beta 8cx with a different HF driver - I skimmed it up to post 88
https://translate.googleusercontent...t=3815&usg=ALkJrhg7Q7v_gmHjccU8Ky1jA42syorH3Q
final result
https://translate.googleusercontent...t=3815&usg=ALkJrhg7Q7v_gmHjccU8Ky1jA42syorH3Q
final result
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XKik Beta 8CX w/ D280Ti Sound Clips
I installed the PRV D280Ti compression driver onto the back of the 8CX. It is a hefty CD, with a magnet almost as big as the woofer. I connected the two drivers with bi-amp (TPA3116D2) and miniDSP for XO and EQ. Here is the Beta 8CX with the D280Ti mounted on it and about to go back into the XKi.
Here is the completed speaker with K-aperture made of same 3-ply CLD sandwich construction. It is screwed straight onto the thick cardboard layers of the main panels using drywall screws. It is quite stiff and doesn't hardly flex, having the CLD gives it a dull thud with a finger rap.
Here is the measured frequency response with the CD installed. I am using a 2kHz 24dB/oct BW XO here. Only a mild +3dB high shelf EQ from 4.5kHz on up was applied to get the HF flatter, and a +3dB low shelf from 80Hz and below was applied (HD was still decent so I don't think it's a big deal). Note the huge hole at 1kHz - trying to figure out how to fix this - if I can this will be an awesome speaker because even with the hole, it sounds very nice as you can hear below.
Here is the corresponding impulse response - a clean pulse with a little low level oscillation that is coming through a bit sibilant. I should note that this is my very first real compression driver! Up to now, I have only used cones, domes, and pleats. It sounds quite good actually considering this is a budget priced driver at $40. One way to fix this is to use a CD that has a lower XO capability but those are pricey. Another option is to build a custom coax with a homemade coax using a 3FE22 mounted onto the internal horn (use the horn as the rear mounting tube and serving as rear driver chamber with driver protruding out front of woofer). Then I can use it with a XO at say, 600Hz.
The dynamics are very clean and quite punchy. I was standing in front of it and could feel the kick on chest at moderate volumes. The cone doesn't appear to move much, at max volume with the TPA3116D2 putting out about 17 volts, the cone moved maybe 3mm on kick drums. It was very loud, but sounded clean still. Here is the RTA of a 70Hz sine wave to check for HD levels and absolute SPL levels at 1m and 2.8v. I am getting about 0.5% THD at 95dB at 70Hz.
Overall, not a bad start for prototype number 2. Remarkable is the lack of the Karlson "W", but now I have a big hole at 1kHz... if you look carefully at the dip, it has an up blip making it a very small aspect ratio "W" still.
I installed the PRV D280Ti compression driver onto the back of the 8CX. It is a hefty CD, with a magnet almost as big as the woofer. I connected the two drivers with bi-amp (TPA3116D2) and miniDSP for XO and EQ. Here is the Beta 8CX with the D280Ti mounted on it and about to go back into the XKi.
Here is the completed speaker with K-aperture made of same 3-ply CLD sandwich construction. It is screwed straight onto the thick cardboard layers of the main panels using drywall screws. It is quite stiff and doesn't hardly flex, having the CLD gives it a dull thud with a finger rap.
Here is the measured frequency response with the CD installed. I am using a 2kHz 24dB/oct BW XO here. Only a mild +3dB high shelf EQ from 4.5kHz on up was applied to get the HF flatter, and a +3dB low shelf from 80Hz and below was applied (HD was still decent so I don't think it's a big deal). Note the huge hole at 1kHz - trying to figure out how to fix this - if I can this will be an awesome speaker because even with the hole, it sounds very nice as you can hear below.
Here is the corresponding impulse response - a clean pulse with a little low level oscillation that is coming through a bit sibilant. I should note that this is my very first real compression driver! Up to now, I have only used cones, domes, and pleats. It sounds quite good actually considering this is a budget priced driver at $40. One way to fix this is to use a CD that has a lower XO capability but those are pricey. Another option is to build a custom coax with a homemade coax using a 3FE22 mounted onto the internal horn (use the horn as the rear mounting tube and serving as rear driver chamber with driver protruding out front of woofer). Then I can use it with a XO at say, 600Hz.
The dynamics are very clean and quite punchy. I was standing in front of it and could feel the kick on chest at moderate volumes. The cone doesn't appear to move much, at max volume with the TPA3116D2 putting out about 17 volts, the cone moved maybe 3mm on kick drums. It was very loud, but sounded clean still. Here is the RTA of a 70Hz sine wave to check for HD levels and absolute SPL levels at 1m and 2.8v. I am getting about 0.5% THD at 95dB at 70Hz.
Overall, not a bad start for prototype number 2. Remarkable is the lack of the Karlson "W", but now I have a big hole at 1kHz... if you look carefully at the dip, it has an up blip making it a very small aspect ratio "W" still.
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Overall, not a bad start for prototype number 2. Remarkable is the lack of the Karlson "W", but now I have a big hole at 1kHz...
Other than the dip at 1.5k this response looks great! Low distortion is a bonus! This design has lots of potential XRK... Keep up the GREAT WORK
way KooL ! - - when you get this one sorted, you need to go to a larger coax or larger woofer plus K-tube. due to lack of affordable strong coaxial woofers, Beta10cx is about the only game in town and should work well. That must be a pretty good cabinet to do well on the amp's max with kickdrum.
how's it sound on good older blues stuff? - it sounds fine on Rebecca - here's one of my favorite cuts but the bass sounds heavy on my gaming cans plus its from an era
where things were panned a lot to one side or another (I've got a tube mic mixer like that)
https://www.youtube.com/watch?v=rw2ZIjYBjoM
a good drum solo would be cool - Beta8cx in a "K10 size" (about 1 cubic foot rear/0.5 cubic foot front) had more excursion than I like - I think the rear chamber was a bit too big for best power handling - Beta10cx in a stock K12 was more suitable - as Qts moved up,
BetsyK had good cone control in K12 - good enough for the tinsel leads to rattle out of their eyelets
besides p-p and SE tube amps plus pp class A solid state, I've a 1KW cheap Crown to whomp new K-variants - lol
what do you think of it vs the other K's ?
how's it sound on good older blues stuff? - it sounds fine on Rebecca - here's one of my favorite cuts but the bass sounds heavy on my gaming cans plus its from an era
where things were panned a lot to one side or another (I've got a tube mic mixer like that)
https://www.youtube.com/watch?v=rw2ZIjYBjoM
a good drum solo would be cool - Beta8cx in a "K10 size" (about 1 cubic foot rear/0.5 cubic foot front) had more excursion than I like - I think the rear chamber was a bit too big for best power handling - Beta10cx in a stock K12 was more suitable - as Qts moved up,
BetsyK had good cone control in K12 - good enough for the tinsel leads to rattle out of their eyelets
besides p-p and SE tube amps plus pp class A solid state, I've a 1KW cheap Crown to whomp new K-variants - lol
what do you think of it vs the other K's ?
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Other than the dip at 1.5k this response looks great! Low distortion is a bonus! This design has lots of potential XRK... Keep up the GREAT WORK
Thanks! Credit goes to Freddi for the inspiration and for providing me the drivers to test this out.
some coaxial can be converted to "koaxial" with a K-tube instead of a flared expansion piece - it might be scary and destructive to see if an Eminence cx piece would remove - be a good idea to as Tony Lucas. With the screen removed, a tube beveled to fit into the horn would work - there would need to be some sort of putty used to smooth the haphazard transition.
a diy coax using a mini Faital pro would be interesting.
does your Beta8cx based XKi seem to play loud enough for a medium room without the cone moving "too much"?
a diy coax using a mini Faital pro would be interesting.
does your Beta8cx based XKi seem to play loud enough for a medium room without the cone moving "too much"?
I have Buddy Guy on the second clip, but will listen to your Muddy Waters clip - I like Blues.
I think compared to the small Karlsonators I have this one certainly packs a real punch, also being made of CLD tri-ply really cleaned up the HD so it sounds cleaner than any of my small K's down at 60Hz. I think the aperture may be a bit small for this 8in. I may open it up a bit to let more HF out. The polar response sounds quote uniform with my ear walking around - and the sound is all around big. If you put it next to a wall, the bass is really something - not lacking a sub. Even though the cabinet weighs maybe 3 lbs the drivers weigh maybe 12lbs so itbis still a hefty speaker. Can't imagine whatnot would weigh made of BB ply though.
I like blues a lot (but not Clapton) - - Carlos Montoya's old Crystal Clear cd on Laserlight should sound good for guitar of a different genre - open her up a bit it would be cool to have a relatively small speaker which could do decent drum reproduction - I wish the solo below had been recorded with better fidelity - its still pretty dynamic https://www.youtube.com/watch?v=aRVjmlO6S5A
it would be cool to have a relatively small speaker which could do decent drum reproduction - I wish the solo below had been recorded with better fidelity - its still pretty dynamic https://www.youtube.com/watch?v=aRVjmlO6S5A
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Xrk971 at Jennygirl thread you changed some peaks and valleys by a PVC pipe system is that technic doable in this little box for the 1 kHz valley or even further can the technic fight the Karlson "W" in general. http://www.diyaudio.com/forums/subw...060-vs-3015lf-tapped-horn-44.html#post4080473.
Sound clips have a hint of as one or more high Q PEQ is set and they too aggressive, rings and bites a little in high midrange to low treble area, that said know its still in development and guess also drivers brand new and then could benefit some burn in time massage.
Sound clips have a hint of as one or more high Q PEQ is set and they too aggressive, rings and bites a little in high midrange to low treble area, that said know its still in development and guess also drivers brand new and then could benefit some burn in time massage.