Replacing Driver in KSW12 with Vega 12

[toussi1]

I have finally found the perfect driver for the replacement of the KSW woofer with a new one. The only reason i would do such a thing is because i find the KSW really boomy. The Cerwin Vega SERIES 12 (red surround) : QTS : .33 VAS: 80 LITERS and a FS of 23HZ. Xmax is rated at 19mm. According to my box program this seems a pretty good match for the box of the KSW-12 : about 1.1 cubic feet and TUNED port at 38.5 HZ. YOU GUYS help me out an plug that data into your programs and tell me if it is reasonable idea. Thanks.

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[JuneBug]

I was curious after I read this article, and decided to try this out as an experiment, just because I didn't have anything else better to do. I looked around for the specs to the Cerwin-Vega subwoofers, and found that the Thiel/Small parameters would seem to work for the KSW12 enclosure.

I was able to get a Cerwin-Vega 12D4 (Dual voice coil) sub relatively cheaply on Ebay, and proceeded to do the change. This thing has a nominal 4 ohm rating on each coil, so I have decided to wire them in series initially (for an 8 ohm load) to make sure I didn't blow up the sub's plate amp.

I only put the driver in last Friday, so the driver probably still needs more break-in before it sounds its best, but here is what I can say so far:

1. The CV driver is definitely much more efficient than the stock driver (it's efficiency is rated at 96 dB). It can get very LOUD, very quickly, and do it effortessly.

2. I have been tinkering with the crossover setting for it, so it would match up with my Forte's. I initially left it at the original crossover setting that I had for the stock driver, but quickly discovered that I had to dial it way down. The initial setting created severe overlap with the forte's and the result was *extremely* boomy. I had the original driver set to a bit over 60 Hz, but have had to drop it to a bit less than 50Hz. I will probably keep fooling around with it, but the match seems OK at that setting in my living room.

3. This thing goes much deeper than the stock woofer. I was watching the movie Punch Drunk Love the other night, and there is scene in it that involves a very unexpected car crash. I thought I was going to have a heart attack when it happened.

4. When playing music (like jazz), it creates a better sense of the acoustic space than the stock driver. I was playing the 1981 Glenn Gould recording of the Goldberg Variaitions last night, and it really did feel like I was right there in the studio listening to him play. The Forte's have a lot to do with that, but the illusion of the reverberant space was much better than with the stock driver.

I still have a lot more variations that I can try with this driver, such as using only one of the voice coils for a 4 ohm load, or wiring the two coils in parallel to try a 2 ohm load. However, at the volumes I listen at, it is producing more than enough deep,loud bass as is.

Anyone have any thoughts?

[I_hear_the_strings]

You know, I have always wanted to know if it was possabdle to do so. Over the years my poor subs have been played to death and I think that they are about ready to retire. So do you guys think that the 10's would work just as well as it did for the 12's.

[JuneBug]

I would think that, as long as the driver's parameters fit the box, it should work. Given how cheap you can get a high quality driver these days, it really can't hurt to try it out. And for the faint of heart, You can't get much simpler than this. This is a completely reversible experiment, with the only thing required is removing the old driver and replacing it with the new one.

I have continued to tweak the crossover settings on the KSW12, and have dropped it even lower, to just over 40 Hz. It's hard to know exactly because of the way the scale is marked on the KSW12's variable crossover. This lower crossover point makes for a better balance between the Forte's and the sub, at least for music.

I am going to keep it like this for a while, until the CV driver breaks in completely.

[JuneBug]

Just wanted to let people know how this experiment has gone. After a bit more tweaking, I ahve come up with a few more modifications to this beast.

First off, I used WinISD to model changes to the port length. The CV manual suggests tuning the port to 35Hz, but this ends up creating a noticable hump in the frequency response at around 40Hz that throws things off. I eneded up increasing the factory port length by increasing length 1 inch. This yields a box that, with this driver, is ported to ~28 Hz. This eliminates the frequency response hump, and extends the lowest usable bass with this compbination box/driver. (I would also mention that the easiest way to fool around with various port lengths is to use a cardboard mailing tube, which is dirt cheap and actually is a bit sturdier than the port tube that came with the stock KSW-12).

So what has been the final result? This combination gives me all the bass I ever wanted and more. I have deep, fast bass, and I am reaching 20Hz bass without breaking a sweat. With the stock driver, there was little more than port noise at 20 Hz. Now you can actually *feel* those deep bass notes.

Also, a nice side effect I have found is that since the box doesn't produce the peaky bass that it originally had with both the stock driver (and the unmodified port, I have been abe to substantially dial back the volume level of the sub, and still get incredible bass response as well as finally getting the subwoofer to "disappear".