Ultimax vs Reference HO

[DIY Audio Guy]

I am getting ready to upgrade the subwoofers in my truck. I plan to go with a pair of 10's in an under-seat enclosure. The Ultimax and the Reference HO both do well in small enclosures, my current box has .65 cuft per side before woofer displacement.


Links for your convenience:
https://www.parts-express.com/dayton...oofer--295-463
https://www.parts-express.com/dayton...-coil--295-510


The Reference HO is dual 4 OHM, so I can wire 4 voice coils in parallel to get a one-ohm load. The Ultimax is dual 2 OHM. I wonder if I would be better off to use a single ultimax in a ported enclosure.


Which one would you pick? I am also willing to entertain suggestions in the same price range and would love any advice you all may have.

[Grinder]

If I had enough power, I'd probably go with the dual HOs sealed - primarily due to the considerable vent length and displacement of such a small cabinet for the vented UM. But then, so much depends on your vehicle, sub placement, processing, preferences/tastes/expectations, etc.

Hopefully this will help you decide:

Green: 1x UM in 1.55 ft^3 at 26 Hz (500 watts) 22 Hz F3 (4" tube vent x 29.5" at 34.4 m/s peak velocity).

Blue: 2x HO in 1.3 ft^3 combined (1,200 watts) 44.4 Hz F3.

[Smitty]

I need start by saying I have not worked with or heard an Ultimax sub. I would go with the HO's mainly for same reasons stated above. I could be biased since I listened to an HO in a car last year and that is what is going in my newest build. Ive also recently been doing sealed and IB setups after years of exclusively ported so that could a factor as well. I know the HO can sound very good in a sealed enclosure.
While we are on the subject of HO vs Ultimax, does anyone have any feedback based solely on SQ?

[DIY Audio Guy]

Thanks so much for modeling that for me in WINisd. I have WINisd and have not had a chance to model the drivers. I am seriously thinking about giving a passive radiator a try.

[Grinder]

Thanks so much for modeling that for me in WINisd. I have WINisd and have not had a chance to model the drivers. I am seriously thinking about giving a passive radiator a try.

Yeah, a PR could be just the thing for the UM in limited space.

[DIY Audio Guy]

Yeah, a PR could be just the thing for the UM in limited space.

We don't see a lot of PR's in car audio. But it is a viable solution for the tight confines of an under seat enclosure.

[Grinder]

We don't see a lot of PR's in car audio. But it is a viable solution for the tight confines of an under seat enclosure.

It might bear mentioning that, due to their considerable added cone weight, PRs should only be mounted vertically.

[Oscar]

I need start by saying I have not worked with or heard an Ultimax sub. I would go with the HO's mainly for same reasons stated above. I could be biased since I listened to an HO in a car last year and that is what is going in my newest build. Ive also recently been doing sealed and IB setups after years of exclusively ported so that could a factor as well. I know the HO can sound very good in a sealed enclosure.
While we are on the subject of HO vs Ultimax, does anyone have any feedback based solely on SQ?

While the HO's can definitely hold their own (haven't heard my 10" HO yet, but based on what I've read), the UM series is no slouch either in the SQ department. The 8" Ultimax is used by Legacy Audio, in my Calibre speakers that I bought back in summer of '17. Suckers set me back $6,300 and they are worth every penny! The HNIC at Legacy Audio doesn't waste his time with anything that isn't truly SQ oriented with low-distortion. And neither do I.








That's an 8" UM with dual 8" PR's with a s&#-ton of power behind them. Bass is awesomely clear, but it's the whole system that makes the bass sound great (with regards to music with bass-guitars and real bass-drums). It's funny because the heart of SQ-bass reproduction as I've come to find out, is in the midrange and lower-treble. The cleaner those are, the better real bass instruments are reproduced.

[BigAl205]

I love my little Ultimax

[NoDestiny]

15" Ultimax with 4.5 cubes, 1lb stuffing per cube, sealed in my little Insight (2-seater hatchback) and it does SQ with authority.