RSS390HO-4 vs UM15-22 for sealed sub with Linkwitz Transform

[tonyfg]

Hi guys!

I'm thinking of building a sealed 15" sub mainly for listening to music at home.
This will also be used a couple of times a year for parties where it will be played pretty loud. I know ported would be better for that, but it's more of a secondary goal.
I'd also like to keep the enclosure below 150L of internal volume (before stuffing) but would be willing to get closer to 200L to keep amp demands under control.

I modelled a few volumes on WinISD using both drivers and found that the RSS is quite ok with enclosures as small as ~90L, while the Ultimax likes to be in a bigger enclosure and starts to look reaaaally good when nearing 200L.
Using the midterm 150L I found these tradeoffs:
- RSS uses less power above 50ish Hz and more power below that.
- RSS is supposed to be lower distortion, but I can't find figures.
- Ultimax has higher Xmax (12mm vs 19mm), so will handle higher power on the low frequencies.

As for the linkwitz transform, I would build the sub and measure it in room first, as I'm not sure what the best tuning would be to compensate for room gain (I might even be happy with the sound without EQ!).

Assuming I can get whatever amplifier is best for this application, which driver and enclosure volume would you guys recommend?


Thanks for your insights!

 

[zettairyouiki]

You've pretty much covered all the bases on the merits. You'll just have to pick your compromises now.

It also does depend on exactly how low you're doing a linkwitz eq to. The lower you want to go, the more important that 19mm of xmax is going to become and will tip towards the ultimax.

 

[mayhem13]

Agreed......if sub 20hz content is your goal, the 19mm xmax will become paramount.

 

[tonyfg]

You've pretty much covered all the bases on the merits. You'll just have to pick your compromises now.

It also does depend on exactly how low you're doing a linkwitz eq to. The lower you want to go, the more important that 19mm of xmax is going to become and will tip towards the ultimax.

Yeah that's what I was thinking, but it's always good to get some feedback from the pros before I start cutting wood

I might go with the Ultimax just for the peace of mind in knowing it won't bottom out as easily. I'm also thinking it would give me more flexibility in case I want to do a rebuild in the future. It looks freaky good on a vented enclosure of around 430L (if only I had that kind of space...).

 

[Lunchietey]

A few days late on this topic but I have an ultimax 15 in 5 cubes sealed and it's a great sub. Very clean, very good low frequency extension.

Extremely happy with the sub and no need to build a massive box for stupidly low frequencies unless that's your thing. Just in 5 cubes sealed with no linkwitz transform you will pick up some very low(inaudible but you can feel them) sounds in some movie tracks. Have lots of power available for this driver though if you want loud party music(500wrms and up) as it doesn't sound 'loud' being so clean. By that I mean it's not really 'punchy' but also not exactly slow either. Will thud away happily though just make sure your main speakers have decent bottom end and use a lowish crossover-60hz is where I run mine. It's still clean to 80hz no problem but I find pro drivers are much happier from 60 and up with the Ultimax only doing the really low stuff.

Oh and another thing, seriously low bass goes a looooong way into your neighbours houses haha