That is not a pretty alignment.
You want a slow monotonic roll-off, then the room will bring it back up.
And why 1x18 instead of 2x15 push-push.
dave
You want a slow monotonic roll-off, then the room will bring it back up.
And why 1x18 instead of 2x15 push-push.
dave
I would not tune it that low, more like to 30Hz with 150L cabinet and a big slot port (like 50cmx10cm and 93cm long). crossover at 125Hz (or lower) for this result. You loose 2dB sensivity but got a more or less flat response in this alignment to 30Hz.
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Greets!
Depends on your performance goals, so for now just pointing out that this is a pioneer's spec woofer design, so Vb = Vas/1.44, Fb = Fs will get you the best trade-off between net box size [Vb] Vs efficiency [eff] Vs bandwidth [BW].
...until you add the effect of the room 🙂
The OP didn't indicate where he was planning to use this design, but if it's for a HT subwoofer, I'd tune at Fb and aim for a response that dips slowly down from 100 Hz to Fb. Room gain will bring that right back up.
The OP didn't indicate where he was planning to use this design, but if it's for a HT subwoofer, I'd tune at Fb and aim for a response that dips slowly down from 100 Hz to Fb. Room gain will bring that right back up.
+1 for this case to the point of considering using an EBS alignment tuned to the lowest room mode [~344 ms/longest room dimension/2], so if really long, then consider multiple sealed.
Thanks for good answers!
I will use the sub for HT and music, but I will prioritize music.
My room is 8mx5m, so the lowest mode will be 21,5.
But I will probably move in a year.
I will change the design and use 2 big ports in the front close to the floor, and the ports will be 3D printed (so I can test different shapes).
Maybe use Vb=vas/1.44, Fb=Fs and try different shapes of the ports and see if the dip at 50hz can be reduced?
I will use the sub for HT and music, but I will prioritize music.
My room is 8mx5m, so the lowest mode will be 21,5.
But I will probably move in a year.
I will change the design and use 2 big ports in the front close to the floor, and the ports will be 3D printed (so I can test different shapes).
Maybe use Vb=vas/1.44, Fb=Fs and try different shapes of the ports and see if the dip at 50hz can be reduced?
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It looks like you may have modelled Vas*1.44, not Vas/1.44, so you might try looking at that first 😉
Using 2 15s push-push (ie active reaction force cancelation) dramatically reduces box load, making for a much easier to build, and rasier to lift, box.
dave
I thought the simplest and best performance-price ratio sub one could build was a 18” 60x60x60 as most commercial types?