efzauner Posted February 14, 2007 Share Posted February 14, 2007 Hi... So I picked the Infinity Perfect 12.1 . It seemd comparable to Dayton titanic 12" and I got a pair cheap in Canada on ebay for under $100 each. (retail list is $400) I also got a Crowne comtech T400 250watts x 2 into 4 ohms for $150... have an electronic cross over or to use the HT receiver. Here are Win ISD Pro alpha results. Green in automatic WinISD result and red is my tweek. to reduce port lenth, increase efficiency... Please comment on the results if this is the right track before I cut MDF... Note PE is 350w but the design is with signal of 200w SPL.pdf Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 14, 2007 Share Posted February 14, 2007 Was this modelled with WinISD Pro??? Did you acount for voice coil heating?? If you did not, I would try to build it to somewhere in the middle of the two.... as the VC temp increases, the output above the bottom "peak" will fill in. The result will be more linear FR at higher SPL's. Quote Link to comment Share on other sites More sharing options...
efzauner Posted February 14, 2007 Author Share Posted February 14, 2007 thanks...but do you see the SPL.pdf? I cant ? I also have cone excursion and port velocity..also added a hp filter to redue excusion under 20 Hz cone ex.pdf Quote Link to comment Share on other sites More sharing options...
efzauner Posted February 14, 2007 Author Share Posted February 14, 2007 and port velocity port vel.pdf Quote Link to comment Share on other sites More sharing options...
efzauner Posted February 14, 2007 Author Share Posted February 14, 2007 Was this modelled with WinISD Pro??? Did you acount for voice coil heating?? If you did not, I would try to build it to somewhere in the middle of the two.... as the VC temp increases, the output above the bottom "peak" will fill in. The result will be more linear FR at higher SPL's. You mean the upper peak will go down because of increased resistance and lower Q? But you think the overall design will work. I am not missing anything here. It seems too easy! Dont know what parameters to use to model the heating.. did not come with the TS parameters. are there some rought figures? Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 14, 2007 Share Posted February 14, 2007 What are the manufacturer suggestions for the cabinet? If you wanted to be real hardcore you could try to simulat the non-linear behavior of the driver to get an idea of how it will behave at the extremes. Right now it looks like a pretty good place to start - the green line is definetly better though. When building the cabinet, try to err on the side of too large for the interior volume. Also, it's a good trick to make the port too long and then trim it down to taste. The physical volume of the cabinet doesn't always equate to its effective volume (since the shape isn't going to be a perfect sphere). Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 14, 2007 Share Posted February 14, 2007 I can't see the spl, but looking at the excursion, you can safely add a little more power input..... and I would tune lower, like the green trace... you see the small peak at the lowe end? As the voice coil warms, the Qes decreases, excursion increases ( near tuning from reduced Qes ) and the woofer "likes" a bigger box. The small peak at the low end will go away, resulting in a flatter FR at higher drive levels. Trying to model for large signals can be vastly different from trying to achieve a ruler flat FR at 1 w power input. With a subwoofer there is not much chance of it operating near 1w, so if you model for higher temps and drive levels, it becomes more linear in the region where it operates most. Make sense?? Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 14, 2007 Share Posted February 14, 2007 Port size is adequate, if you are not in a hurry, I have a male mold almost finished for making my own port flares out of fibreglass. The mold is on the lathe still, need to final sand ( add a smear of filler in 2 spots ), prime and paint. It is made for 6" diameter PVC sewer pipe ( IPEX ring-tite ), starts at 5 7/8" inside and flares out over 11" outer diameter... if you have time to wait, once the mold is complete, I can whip you up a couple of flares, as I need a few myself. The cost would be minimal, pay for the materials and I'll ship you them...PM if interested. Quote Link to comment Share on other sites More sharing options...
efzauner Posted February 15, 2007 Author Share Posted February 15, 2007 Wow...that is a nice offer. Thanks.. This is my first ported sub design and I know it wont be my last. It is for a temporary HT room (actually kids playroom) and it will be some time before I get the real HT room finished... I dont expect to go to such high volumes so I dont expect to need your nice port flares at this time... Maybe in year or so i would be interested....what do you do for port end correction? Is this considered a flanged? Or does it require manual tuning to get it right? I will make the cabinet bigger and make the port lentth adjustable. Will mostlikely have a bend in it. The WAF factor and Kid factor means that I will make a triagular box about 4ft high that fits in the corner behind the sectional sofa. Thus the sub will be protected from feet.. pens... and other things. Once it is made I can dabble with volume and port lenght and even try to model NL performance so the next iteration for the real HT room is better. But the plots as the are are pretty flat... withing a db or so.. I suspect that the room will make the biggest difference. I am not sure what difference chasing 1db flatness will make in the real room... Thanks for all your help...will probably cut MDF this weekend. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 15, 2007 Share Posted February 15, 2007 Building around the non-linear behaviors isn't really about playing the system at peak levels. It's about maintaining the least amount of distortion at all volume levels. Quote Link to comment Share on other sites More sharing options...
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