Home Forums DIY Speakers and Subwoofers Max-X High Excursion 15" Subwoofer for only $200 – Build Ideas Reply To: RE: Max-X High Excursion 15" Subwoofer for only $200 – Build Ideas

  • mistersota

    April 25, 2021 at 1:05 am

    So I was about to get a pair of sql15s when these dropped onto parts express. I decided that the high inductance and steel basket weren’t bad enough for me to spend another $120 per sub. I built two 24x20x22″ (LxWxH) boxes for them with 1.5×17.5″ (with bracing) 42-45′ long slot ports. They were originally tuned to 19hz’with ~4 cubic ft volume, but after adding r15 insulation to all the walls (with a thin cloth over it) the tuning was 16-17hz. I still need to finish them, but I’m waiting for a warmer day.

     The results were just about what I expected. The simulated and response graphs are very close. The only difference is that there is either more inductance than specified, or, more likely, my slot port which has both an extreme aspect ratio and a sharp turn at the back of the box, lost me 2dB. Oh well! I expected that. BTW the response was measured in half space ground plane in my yard. The nearest building was about 100 feet away, but some trees could have contributed to the wavy response above 60hz. I would bring the sub into the field across the street, but its obviously over 100lbs and this is an adequate measurement for my purposes.

    I designed these to be EQed and with 6dB of eq and a little taming to the inductance hump. I have a response flat to 16hz with an f3 of 14.6. Honestly, I wasn’t expecting to get so much extra volume from the insulation so this is well below what I expected, but the model for 16hz tuning agrees.

    I don’t have a way to measure max spl but my house does certainly shake with both of these running off a crown xls 2502. I’m yet to actually clip the amp because the burst tones were cracking my house and I was worried for my windows.

    The cone excursion is under xmax at full power down to 14hz. Dayton states a 70%bl of 24mm so I am running a 13hz 4th order high pass. 

     The port velocity is higher than 17m/s like @123Toid mentioned with his no dsp version, but that only happens around 19hz with a peak of 25.5m/s at 14.5 with the HP filter applied. I heard it when pushing high-power bursts, but it will be inaudible during actual listening.

     Overall, counting wood (2 sheets of 3/4″ particle board because MDF prices are crazy high here), subs, minidsp, and amp (Crown 2502 used), I’m almost exactly $1000 into this pair of subs (Excluding the table saw, jigsaw, and router I used). If you get something like a Behringer nx3000 which I’ve seen for $260 on sweetwater, you could have them for even less. For $1000 there is really nothing else out there that can put out these numbers in cabinets this small. It seems that Dayton has engineered this sub to fit an enclosure that is the perfect size. Small(relative), but not so small that the port won’t fit.

    I have a friend with dual pb3000s and I don’t think they hold up to these, especially at sub 20hz frequencies. Pb4000s seem like a better match. Maybe you guys with more experience with those subs can provide input. If you’re looking for performance like that without a few bells and whistles minus $2800, these are great subs for the money.

    If you guys are interested in the performance of a sealed version, let me know. I’ll need to make a pair for my college apartment when I move back next fall anyway.