[svtcontour]

Hi everyone, glad to be posting my first item on this awesome forum

I've got a pair of Vifa 10" PL26WR09 4ohm drivers which were to be used for a floorstanding 3 way speaker which didnt materialize. So now that I have them sitting around, I'd like to use them as subwoofers for my modest home theater if possible.

At the moment I'm using a pair of old 8" Yamaha YST-SW90 which are fine but they just dont go low enough. I'm thinking that these 10" each in a 2.8cf box tuned to about 22Hz might do the trick. I'd keep the crossover around 50Hz or so.

I'm wondering if there would be any reason not to use those drivers in a smaller room if my listening levels and bass requirements are not very excessive? Is the only real difference between my drivers and a proper 10" subwoofer the ability to play louder and take more abuse? At modest sound levels, would they both sound just fine or will a true subwoofer be cleaner and more accurate?

By the way I'm going to be powering it with my old Soundcraftsmen PM860 power amp which is rated for 300w RMS per channel into 4 ohms and as a crossover, I will use my AudioControl Phase Coupled Activator.

I realized that specs for the woofers might be nice too

FS 26Hz
QTS 0.35
QES 0.38
QMS 4.49
VAS 110L
LE 1.7
RE 3.2
Xmax 8mm
BL 8.7
VC diameter 50mm
moving mass 55g

 

[SteveCallas]

Hmm, why would you crossover so low to what is really a woofer? 22hz to a 50hz is just barely an octave. I'd crossover no lower than 80hz.

 

[svtcontour]

Hmm, why would you crossover so low to what is really a woofer? 22hz to a 50hz is just barely an octave. I'd crossover no lower than 80hz.

I was kinda thinking that since my main speakers go down to 50 without much trouble, to let them handle that and then have this handle whatever was left over (basically the lowest frequencies)....or would that maybe be a bad idea?

 

[Mike P.]

Welcome fellow Canadian! In 2.8 cu.ft. tuned to 22 hz with a 4 inch port 22" long, the Vifa 10" would handle about 100 watts due to its limited Xmax. It will also require a hi pass filter at 20 hz. As you can see the low end output drops off rather quickly. Should you wish to upgrade in the future, also shown is the CSS SSX10 in the same box size, tuning, port size, hi pass filter and 300 watt input which your amp can provide. It would be a simple matter to swap out the drivers.

 

[svtcontour]

Thanks Mike That CSS driver definitely dow produce tons of bottom end and extension but its got me thinking. Looking at the graphs, it looks the CSS driver is rated at 85db efficiency while the Vifa is 89db. Does that mean that in reality, given the same wattage (providing its not too much), we can just push the whole curve of the Vifa driver up by 4db? If thats the case, then as long as I dont push the driver that hard, I could possible get a lot of bass without much power - is that what it means or does it not quite work that way when taken from paper to real life ???

BTW that curve of the vifa almost looks like what I'd see from a sealed cabinet

Welcome fellow Canadian! In 2.8 cu.ft. tuned to 22 hz with a 4 inch port 22" long, the Vifa 10" would handle about 100 watts due to its limited Xmax. It will also require a hi pass filter at 20 hz. As you can see the low end output drops off rather quickly. Should you wish to upgrade in the future, also shown is the CSS SSX10 in the same box size, tuning, port size, hi pass filter and 300 watt input which your amp can provide. It would be a simple matter to swap out the drivers.

View attachment 17692

 

[Mike P.]

The SPL you see in the above graph is the most you'll get due to the Vifa's excursion limits and 100 watts that it takes to get there. The modeling was done with the stated parameters of both drivers.