Home Forums DIY Speakers and Subwoofers Dayton Reference HO vs Dayton Ultimax

  • Dayton Reference HO vs Dayton Ultimax

  • elliottdesigns

    November 4, 2019 at 11:31 am

    All I know is that the reference has better power handling and works better in small spaces, generally is said to be better than the Ultimax series for car audio subs. My personal taste is a sealed enclosure as I can get smaller enclosures with a nice smooth roll off (6db), so I can really dig into those subsonic frequencies. I also generally prefer the transients of a sealed sub as the bass seems more controlled. If you want any decent output of your port with a dual ultimax setup you are going to need a massive enclosure. My preference would be to use the Reference HO, especially as if you get the dirac live it will make the phase of the output easier to control as the port will introduce group delays that can’t easily be countered, even with frequency band phase correction. If you head back over to the car audio build page I have put more information on dirac live and even found that they recently released DIY audio versions of their processors!

  • 123toid

    November 4, 2019 at 3:25 pm
    Posted by: @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: 



    The Reference HO is dual 4 OHM, so I can wire 4 voice coils in parallel to get a one-ohm load.  In the car audio world power at 1 OHM is very cheap.  A decent 1200 watt amp can be had for well under $300.  So I am leaning in that direction.  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.

    This is a great question and honestly harder to discern then when you first look at it.  I already had both of these in winISD, so I did a quick simulation.  For this simulation, I put both drivers in a .55 cubic foot box.  Now the HO says it has an RMS of 600w and max of 1200w, but it hits excursion (everywhere below 48hz) if you go past 500w in that sized enclosure.  So you really don’t want to feed it more than 500w.  The Ulitmax on the other hand can take up to 900w easily before touching excursion.  So at this point, everyone would think the Ultimax is the clear winner.  However, what we haven’t considered is spl.  The HO is far more efficient.  Believe it or not, due to that efficiency the HO plays louder using 500w (about 1db) than the Ultimax does at 900w.  The Ultimax does tune a little lower 41 compared to 46, but in a truck that really isn’t going to make a big difference. So for me, you would go with the Ultimax of want to run a lot of wattage and don’t want to be concerned of mechanical damage.  Or if you decide you want to try it free air, which it could do as well.  And you would go with the HO if you want to use less power. 

  • diy-audio-guy

    November 4, 2019 at 3:59 pm

    Thanks for doing that!  After modeling a few things in WINisd I have learned that the power handling listed in the specifications it’s just a rule of thumb.  A convenient shorthand for pairing drivers with amplifiers.

    Another option is to go with a single sub and a passive radiator.  The inexpensive 12 that you posted about here on the forums should do the trick. I like that the weight is on the front of the cone. No need to take the driver out to make adjustments.  It really seems like the perfect application for a passive radiator:  no room for a port and no good place to put it.  

    I’m also looking for an excuse to make my own fiberglass box.  I’ve never used fiberglass before and I want to give it a try.  I would have to relocate my amps two under the front seat, but I bet I could use some of the dead space under the back seat, raise the seat up a bit and get almost two cubic feet to work with.  


    I asked for recommendations for alternatives to Dayton Audio subwoofers.  Honestly that’s more of a challenge than a request for advice. I doubt that anybody could find a woofer with better specs than those two drivers at that price point.

  • diy-audio-guy

    November 14, 2019 at 1:43 pm

    I decided to go with an Ultimax, going to do some experimenting.  I can always swap out an HO later if I want to.



  • 123toid

    November 15, 2019 at 7:57 am


    Loving your channel.  I cant wait to see this.  I think you are going to be very happy with the Ultimax.  Funny, I was just designing an ultimax box for Doublsmm’s car.