Yes, that sounds about right. I've updated my hornresp.dat file if you want to download it. The current Frankenclosure is #024 (has the 7.5 cm port). It does chuff some. While I understand the concept of keeping velocity below a certain speed, I have yet to find out how to sim this in hornresp. I do see that making the port diameter bigger/longer I can tune for a similar response, but again, how do I know when it's big enough? Can someone point me to a page showing how multiple ports would work? I have lots of 4" PVC and a lot of small holes might be easier than one big one.
Latest hornresp file is here:
Index of /shared/TEMP
The next box will be better thought-out (not necessarily built but we can hope.) In fact, I am slowly assembling suitable materials that will not resonate. It takes a while, because each headstone is pretty heavy and I don't want to throw my back out loading and unloading them. Pity there aren't more of the traditional masoleums in this part of America. Then I could hire a team of ghouls and a big truck and make a night's work of it
Latest hornresp file is here:
Index of /shared/TEMP
The next box will be better thought-out (not necessarily built but we can hope.) In fact, I am slowly assembling suitable materials that will not resonate. It takes a while, because each headstone is pretty heavy and I don't want to throw my back out loading and unloading them. Pity there aren't more of the traditional masoleums in this part of America. Then I could hire a team of ghouls and a big truck and make a night's work of it
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Hi Soldermizer,
First a link that has a wealth of data on box design, construction and ports:
Porting at Subwoofer-Builder.com
Multiple 4" PVC ports will work well, just simulate w/ a single port to get the needed total area, and divide it by the area of the 4" pipe that'll give you the number of ports you need. The length(s) stays the same. Dual 4" ports is just about a minimum for a single 15" driver, so as a starting point you might want to try 4ea. 4" ducts. Calculate the port length in Hornresp (or, e.g.: WinISD...). I often helps to make the ports a little too long that way you can cut them off a little. I like to use an internal flange, e.g.: the circle cutout from an 8" woofer hole (or some piece of scrap), and I round the port edges inside and out w/ at least 3/4".
I'll attach a handy little chart that I use a lot when wondering about circle area v. diameter, and multiple ports. (Spreadsheets are a wonderful thing.) Never know what is sitting in the corner, PVC pipe, shipping tubes.....
Be careful w/ the headstone robbery, some people take that personally. 🙂
Regards,
First a link that has a wealth of data on box design, construction and ports:
Porting at Subwoofer-Builder.com
Multiple 4" PVC ports will work well, just simulate w/ a single port to get the needed total area, and divide it by the area of the 4" pipe that'll give you the number of ports you need. The length(s) stays the same. Dual 4" ports is just about a minimum for a single 15" driver, so as a starting point you might want to try 4ea. 4" ducts. Calculate the port length in Hornresp (or, e.g.: WinISD...). I often helps to make the ports a little too long that way you can cut them off a little. I like to use an internal flange, e.g.: the circle cutout from an 8" woofer hole (or some piece of scrap), and I round the port edges inside and out w/ at least 3/4".
I'll attach a handy little chart that I use a lot when wondering about circle area v. diameter, and multiple ports. (Spreadsheets are a wonderful thing.) Never know what is sitting in the corner, PVC pipe, shipping tubes.....
Be careful w/ the headstone robbery, some people take that personally. 🙂
Regards,
Attachments
Thanks, will look at it, meanwhile...
I finally have discovered Hornresp's secret (how to get the particulate velocity at a port) and ... for the Frankenclosure a 12" diameter port approx 1 meter long will tune it fairly flat. So rather than butcher my 10 1/2 Sonotube I bought a 48" unit at Lowe's and forthwith took jigsaw, enlarged to prior 4" hole to about 12", glued on the new tube and it works ... a few leaks but WTF? It's a perpetration in progress... 🙂
Hey I just figured out: if you're single like me, you don't have to worry about WAF, you have the latitude given by the WTF factor instead
>>Be careful w/ the headstone robbery, some people take that personally. 🙂
Not the clients..."While friends and lovers mourn your silly grave, I have other uses for you darling" -- Alice Cooper
I prefer mine at least at room temperature or higher 🙂
I finally have discovered Hornresp's secret (how to get the particulate velocity at a port) and ... for the Frankenclosure a 12" diameter port approx 1 meter long will tune it fairly flat. So rather than butcher my 10 1/2 Sonotube I bought a 48" unit at Lowe's and forthwith took jigsaw, enlarged to prior 4" hole to about 12", glued on the new tube and it works ... a few leaks but WTF? It's a perpetration in progress... 🙂
Hey I just figured out: if you're single like me, you don't have to worry about WAF, you have the latitude given by the WTF factor instead
>>Be careful w/ the headstone robbery, some people take that personally. 🙂
Not the clients..."While friends and lovers mourn your silly grave, I have other uses for you darling" -- Alice Cooper
I prefer mine at least at room temperature or higher 🙂
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Today's insight: "Dual opposed" as regards my builds is that a pair of members here think it's a bad idea 🙂
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