Very beautiful work! Try a dremel tool to make the rebate wider. This has happened to me before. You did not do a test for before paint? Or the paint made it too tight?
The TL simulations are for the plan as drawn. If you modify it by adding a step change to the terminus and change terminus (vent) cross section - it will not perform as designed. That is the most sensitive spot to change things up too. If you change a cm here or there where it is big at the other end of the TL, no big deal. At the exist is where it is narrowest and here is where geometric effects are magnified. My main concern is the abrupt step down to an oval that’s smaller than cross section of TL up to that point. It’s been gradually tapering down at each corner where the area actually increases. A sudden constriction will be seen by the aero acoustics as the new (shorter) TL length boundary condition. The 1/4wave will anchor to that lip. The oval vent now mass loads the TL. So it’s no longer a gradual taper TL as designed. The vent velocities of the original design are very low, you don’t really need to have large round overs to reduce wind noise. There is none. That is one of the things I design for - vent velocities well below 15 m/s at max SPL. That’s not going to be an issue in this speaker.
Hi Xrk971,
I'm lurking the 1st slope passive XO you made but for a sb23NBAC-8 instead the RS25 and the 10F/8424G (I purchased for the foam horn project sme times ago).
I see the cut-off is around 320 hz. I have a noob question please; Have you tried a higher cut-off, i.e. around 600hz to 700 hz with a BW6 as well ?
many thanks, I'm a bit hesitating between a 12/18 lmost perfect transcient pssive and a first slope... 320 hz 6db on the paper seems to me too close to the low end of the 10F due to the low slope. I have no doubt it sounds good but would like to know if you tried higher cut-off and liked what you heard ? (the bafle step is maybe also easier to rule with something near 700/800 hz, though I'm building the box yet so haven't zrd yet for Xsim
many thanks if an opinion about that (fact is I also hesitate with a tweeter above the 10F but I'm constructing à l Haberth in order to change easily the project...)
cheers.
I'm lurking the 1st slope passive XO you made but for a sb23NBAC-8 instead the RS25 and the 10F/8424G (I purchased for the foam horn project sme times ago).
I see the cut-off is around 320 hz. I have a noob question please; Have you tried a higher cut-off, i.e. around 600hz to 700 hz with a BW6 as well ?
many thanks, I'm a bit hesitating between a 12/18 lmost perfect transcient pssive and a first slope... 320 hz 6db on the paper seems to me too close to the low end of the 10F due to the low slope. I have no doubt it sounds good but would like to know if you tried higher cut-off and liked what you heard ? (the bafle step is maybe also easier to rule with something near 700/800 hz, though I'm building the box yet so haven't zrd yet for Xsim
many thanks if an opinion about that (fact is I also hesitate with a tweeter above the 10F but I'm constructing à l Haberth in order to change easily the project...)
cheers.
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Thanks X
My bad, I believed your 4 mH coil on the dayton and the 82 uF parralel to the 10F gave an electrical 1st order 320 hz cut off. I certainly missed something...Maybe the Dayton is not 8 ohms but 4 ohms unit...or I have not simulated with the acoustic center of the drivers...I just took the values of your passive filtet and fill in the Vcap on line filter simulator...
My bad, I believed your 4 mH coil on the dayton and the 82 uF parralel to the 10F gave an electrical 1st order 320 hz cut off. I certainly missed something...Maybe the Dayton is not 8 ohms but 4 ohms unit...or I have not simulated with the acoustic center of the drivers...I just took the values of your passive filtet and fill in the Vcap on line filter simulator...
Many thanks, yes this one, I did not see the graph, my bad... so a near 850 hz XO ?
That's the 4 mH that was puzzling me as I use on line filter page, they say something 320 hz ! and te 61 uF in serie with the 10F as well ! So I miss something in the understanding of it !
C1 + R3 is flatening the impedance ?
I'm going to try this with the 10F 8424GO but for the 22 cm, it will be a SB23NBAC45-8 instead the Dayton... I will report on howw it sounds. Default of the SB23 is a little high odd order after 500 hz but h3 is still around 35/40 db below the fundumental...
So you like better that filter vs an almost transcient with higher slope ?
That's the 4 mH that was puzzling me as I use on line filter page, they say something 320 hz ! and te 61 uF in serie with the 10F as well ! So I miss something in the understanding of it !
C1 + R3 is flatening the impedance ?
I'm going to try this with the 10F 8424GO but for the 22 cm, it will be a SB23NBAC45-8 instead the Dayton... I will report on howw it sounds. Default of the SB23 is a little high odd order after 500 hz but h3 is still around 35/40 db below the fundumental...
So you like better that filter vs an almost transcient with higher slope ?
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In this particular case, the very shallow XO and nice behavior of both drivers works very well. Yes, C1+R3 flattens impedance.
If you want to try a higher order XO but still keep transient perfect, there is a way to do a Harsch passive XO that uses 4th on woofer (2nd order electrical combined with natural roll off at woofer top end) and 2nd order on tweeter. Circa 3.5kHz yields an almost transient perfect response plus steeper filter. I did this with Purifi PTT6.5 and dome tweeter in a waveguide. It sounds exceptional.
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
Specifically, this post:
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
XO:
Here is frequency response:
Here is step response:
If you want to try a higher order XO but still keep transient perfect, there is a way to do a Harsch passive XO that uses 4th on woofer (2nd order electrical combined with natural roll off at woofer top end) and 2nd order on tweeter. Circa 3.5kHz yields an almost transient perfect response plus steeper filter. I did this with Purifi PTT6.5 and dome tweeter in a waveguide. It sounds exceptional.
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
Specifically, this post:
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
XO:
Here is frequency response:
Here is step response:
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Thanks for the tip X, if I go 3 ways I will try it, though I have no active set-up, so staying passive can cost me a little monney...
Ok, so I understood correctly, the passive above is a circa 320 hz passive first order elecrical XO, but the shallow overlap works well here with the Dayton... I will try it with the SB23NBAC if I sucseed to deal with the baffle step as my cabinet will be not the same size.
Thanks again for the tips and input... ah I just need to find a compass router jig here in Europe, have the drivers and chosed a ply cabinet cause of the wood looking whilr still have some foam I keeped from your horn project with the 10F ! Great little driver, I love it, neutral my ears says
cheers...
Ok, so I understood correctly, the passive above is a circa 320 hz passive first order elecrical XO, but the shallow overlap works well here with the Dayton... I will try it with the SB23NBAC if I sucseed to deal with the baffle step as my cabinet will be not the same size.
Thanks again for the tips and input... ah I just need to find a compass router jig here in Europe, have the drivers and chosed a ply cabinet cause of the wood looking whilr still have some foam I keeped from your horn project with the 10F ! Great little driver, I love it, neutral my ears says
cheers...
This is the jig I recently purchased. Generic Chinese job comes under various brands. Buy the cheapest one. I had to drill and tap my router as the holes weren't designed for my router. Works very well and cheap.
A B C Mini Ellipse and Circle Cutting Jig Set for Trimming Machines Woodworking Milling for Hand Trimmer Wood Router(B Set): Amazon.co.uk: DIY & Tools
A B C Mini Ellipse and Circle Cutting Jig Set for Trimming Machines Woodworking Milling for Hand Trimmer Wood Router(B Set): Amazon.co.uk: DIY & Tools
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And some more progress on my build. Have wasted a lot of time on paint finishes which is annoying. I have also made some additional rear panels which will be sort of cld as I will stick them on with butyl. These enclosures like many 1970s and 80s speakers have a recess in the back which will take a layer of butyl and 6mm MDf quite nicely. And so will stiffen up the rear panel without loosing me any interior volume.
Traffic cone is mounted and sealed....I think.! Will test with the woofer cone press test.
I'm hoping my gasket for baffle sealing won't fully compress before sealing the air to allow a degree of isolation from the baffle into the box.
Other than trying to find room for the crossover in there I am working my way through. Would like them done for Christmas but it isnlooking doubtful!
Traffic cone is mounted and sealed....I think.! Will test with the woofer cone press test.
I'm hoping my gasket for baffle sealing won't fully compress before sealing the air to allow a degree of isolation from the baffle into the box.
Other than trying to find room for the crossover in there I am working my way through. Would like them done for Christmas but it isnlooking doubtful!
