# Cerwin-Vega Stroker 18" box



## P1200VB (Nov 29, 2016)

I have a brand new Cerwin-Vega Stroker 18S that I would like to build a box to and use at home. 

In the following PDF file from Cerwin-Vega, there are three different proposals.

http://www.eastaudio.net/kuvat/bbs/apstkr18.pdf

30 Hz Tuning - Deep Bass
35 Hz Tuning - Loud Bass
40 Hz Tuning - Max SPL

In all cases, it is about a box of 162.8 liters plus the volume of the speaker and ports.

Cerwin-Vega recommend either a 8 inch port, two six inch ports or a rectangular port with appropriate dimensions depending on the resonant frequency.

When I simulate these in WinISD it turns out that there is a pretty strong hump right at the tuning frequency.


























The hump is also in the Cerwin-Vega's own curves so obviously they feel that it's okay. But the question is why they do not make the box smaller and get a smoother curve? The efficiency declines slightly but not very much. The ports will be slightly longer but that is no problem. I will have less cone movement, so I will still be able to play as loud before the element reaches its Xmax. Here is a curve of 100 liter enclosure, and 30 Hz tuning frequency.










I'm also wondering why the hump is so much greater for Stroker 18S compared to the 18D. This is also true of the curves in the PDF file so it's not my simulations that is wrong. Here are the curves for Stroker 18S and 18D in the exact same box tuned to 30Hz. Worth pointing out is that Stroker 18D2 simulates exactly like Stroker 18S so that I have chosen not to include it in the comparison.


















The curve for Stroker 18D has a much better shape. Around 123 dB with reasonably straight character right down to 30 Hz is not so bad. Thoughts and ideas on why this may be? Obviously Stroker 18D voice coil is somewhat differently designed compared to Stroker 18S / D2 but why? Stroker 18S / D2 has slightly lower fs which probably means that they also have a slightly heavier coil.

It is no problem to get the shape of the curve good also for Stroker 18S but then I have to reduce the volume. Do you want me to go on any of the Cerwin-Vega's own proposals or should I use smaller volume?

Here are some pictures of the Stroker itself. Feels fresh and clean despite its age.


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## Onyx1136 (Mar 15, 2009)

None of your pictures or links are working.


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## P1200VB (Nov 29, 2016)

Should work now?


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## Hillbilly SQ (Jan 26, 2007)

Probably one of if not the most legendary subs ever built. Like a sexy ugly duckling, and I mean that in a good way. If you have eq to pull down the hump I'd go with the recommended box at 30hz. This way you can eq the hump back in to really shake the house down when the mood strikes. Otherwise, the flattest response you can get with a 30hz tune would be my choice.


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## P1200VB (Nov 29, 2016)

Ok thanks. The curve looks very smooth and fine with 100 liters net and 30 Hz tuning. But the question is if it is not better to tune at 35 Hz instead. If I do that I will still get a lot of output available down to 30 Hz, but the efficiency and power capability increases further up. About 2 dB additional between 35 Hz - 50 Hz where many of the notes of the music lies. Would rather lose a bit of the output below 30 Hz if it means I get a more tight and controlled bass.


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## Mikesounds (Oct 13, 2016)

This was designed by John Fairchild for commercial use, 18 cu ft tuned to 28 hz. Never ran it in winisd, but I'm guessing that it will be an amazing sub for home theater or hifi.


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