[NorCalRP]

Upgradeitis has set in once again. Always wanting more bass brings me to this forum. I currently have a HSU VTF-3 MK4 and an SVS PC2000. I'm takingg a hard look at the Ultimax 18 kit from Parts Express.

Both of my current subs claim to reach down to 18hz, whereas the Ultimax states response down to 19hz. I'm not necessarily concerned about the difference, but am wondering if the Ultimax in the 4ft³ sealed enclosure will have greater output at 19hz than the other two if fed a proper amount of power.

What would the right amount of power be? If I were to get something like the Crown XLS 2502, would that amp be able to drive both subs, or do I need one amp per sub since they have dual voice coils?

A big part of me wanting to do this is my intention to have quads and wanting them to be identical

 

[chiptouz]

Upgradeitis has set in once again. Always wanting more bass brings me to this forum. I currently have a HSU VTF-3 MK4 and an SVS PC2000. I'm takingg a hard look at the Ultimax 18 kit from Parts Express.

Both of my current subs claim to reach down to 18hz, whereas the Ultimax states response down to 19hz. I'm not necessarily concerned about the difference, but am wondering if the Ultimax in the 4ft³ sealed enclosure will have greater output at 19hz than the other two if fed a proper amount of power.

What would the right amount of power be? If I were to get something like the Crown XLS 2502, would that amp be able to drive both subs, or do I need one amp per sub since they have dual voice coils?

A big part of me wanting to do this is my intention to have quads and wanting them to be identical

I am not sure about the svs pc2000 but my @LTD02 designed UM18-22's (I built 2 of them) hit way lower than when I was running one HSU VTF3-MK4. Look up my thread and you can see what I used, how I built them, and some other forum members thoughts. I love them. They are amazing and shake my house.

Chip

 

[LTD02]

in diy, size is one weapon.

ultimax 18 in 4 cubic foot sealed and 12 cubic foot ported tuned to 17hz. max output using 2000 "watts" and 28mm excursion. model is 1 meter, 2 pi.

if you have a smallish room (lots of room gain) and/or are on a bouncy floor, you may like the sealed. if in a largish room and solid floor, the big ported may be the better choice.

 

[Will P]

If you are OK with the 12cu ft box of the ported sub but want more low freq extension you can put x3 18in Ultimax and seal the box. Equalize the subs flat to 19Hz to almost similar output 119dB of the ported single sub and then with the natural roll off you will get 107dB @10Hz and 95dB @ 5Hz. The extra cost is for x2 sub drivers and x2amps.
The enclosure/s total size would remain the same 12 cu ft.
That's another option you have.

 

[Will P]

A big part of me wanting to do this is my intention to have quads and wanting them to be identical

You are absolutely right here - Having identical subs when they work together in the same passband is the way to go

 

[BassThatHz]

One driver per channel is ideal because then you can set delays and EQ independently (and if they aren't the same driver/box different XO's etc etc).

If the amp is dual 2-ohm rated, and the drivers are dual 2-ohms, then you could series the coils and parallel the drivers for a dual 2-ohm load. i.e. 4 drivers on one amp. But then the settings are shared for the 3rd and 4th sub.

Alternatively you could get a DSP FP20k if you need the rack-height and/or need a more powerful amp than the dual 2502's.