This thread is fairly lengthy, but I wanted to take the time to explain the decisions that led up to the need for this build. Stay with me as I promise it’s worth the read, or at least I hope it is. I have done my best to document AND link to the parts used for this project, but over time some links may become broken. Please refer to the item numbers and google them to find additional suppliers if needed.
I have tried to break this thread up into sections. The Backstory & Problem, Solution & Project design, and then Build pictures. Jump to the last post if all you care about is the pics.
“Call me Ishmael”. Lets start with a quick introduction about me. I’m a *bit* of an OCD person, who works in IT for a living (go figure right).
*Edit* Ok, I’m let’s be honest, I’m a MASSIVELY OCD guy who overthinks everything to the chagrin and annoyance at times of friends and family. I don’t start a project or buy anything without researching it till I drive myself batty, and then sit indecisive wondering if I am making the right decision. I’m sure reading this thread in its entirety you will come to the same conclusion.
*Back on topic*
I have been slowly acquiring DIY subs with the goal of increasing the ULF in my large room. I’m a basshead at heart and have always appreciated tight musical deep bass.
Problem: Need MOAR ULF!!!!!
Research: How do I get more ULF
In order to increase the ULF in my room I realized that I either need large ported boxes tuned low (10-15 Hz), or sealed boxes and a TON of power. The pro’s and con’s of Ported v Sealed sub were researched ad nauseum and eventually a consensus was reached. Mainly it was based on the fact that my wife isn’t a fan of large ported boxes, I didn’t have a ton of room to build one even if I wanted too, and if I did build one it would have to be smaller than I wanted resulting in a compromise in performance which I couldn’t accept (see there’s that OCD coming out). That left me to look at sealed subs of a large cone size with a ton of power thrown at them.
Sub Build: Determining the right sub and enclosure size
Looking at subs, it was fairly easy to see, given my research, that a lot of cone surface was needed to get where I was hoping to go. 12 and 15 inch subs weren’t going to cut it without 4 or more drivers, which was cost prohibitive. 18, 21 & 24 inch subs were viable options, with 2 likely getting me “close” to what I wanted. 21 & 24 inch subs would require large boxes, even sealed, given their circumference. Additionally the cost for them tends to be somewhat steep for the obvious reason that most are in the “made to order” category.
Another factor is that I lacked the woodworking tools to build a box, so ordering a flatpack, or buying a custom made one was a MUST. The largest kit available at an affordable (to me) price was only available for an 18 inch driver, which made the 21 and 24 inch subs not a viable option IMHO.
That led me to look at 18 inch, and after again a ton of research in WinISD (again there is that OCD) it was determined the best driver option was the Dayton Ultimax 18. It also helped to know that someone like Mark Seaton was using the same stock driver in his builds in a similarly sized box.
At the time of purchase the intent was to buy 2 of these kits total, however for reasons I won’t get into that didn’t happen. I bought a single Dayton Ultimax 18 flatpack kit from parts express and got it built with the help of a friend. A second one of these never materialized, but what did happen is that at a later date an additionally DIY sub box was purchased which consists of 4 x 12 inch Infinity drivers. When these drivers as a single system, wired for 4 ohms were modeled in WinISD, they had simulated performance very similar to the Dayton Ultimax that was already in use.
That left finding the right amp.
Researching the “right” amp FOR ME:
In researching amp options, it was quickly apparent that the most used option was a pro amp as opposed to a plate amp. The benefits of this are that more powerful amps can be purchased in the future without any modifications to the sub itself. So plate amps were out.
In reading up on pro amps in DIY builds, lots of folks were very happy with DIY subs paired with nuke DSP model amps. The issue’s I saw with the iNukes were largely the fact that they are IMHO ugly as heck, and the fans are loud enough to almost necessitate replacing the stock fan. Realizing that there were mainly issues for me, and not ones most people encountered as the iNukes are intended for pro use. In the pro audio realm the super bright LED’s make it easy to see the display at night, and the fan noise is minimal as they are normally placed far away from the people and speakers. There are always problems when you take an item not intended for a consumer HT setting and attempt to make it work in one. For 99% of folks replacing the stock fan, spray painting the front and covering the lights with tint would have solved those problems. But again my OCD kicked in. Not a fan of modifications that void warranties, and not trusting myself to do a decent enough job (for me) on painting it a different color, that left both QSC and Crown amps as possible options. QSC was eliminated due to again high fan noise, leaving just the Crown.
Crown amps had a very good reputation, overall and had a fairly decent aesthetic to them. They also allowed for RCA OR XLR connectors to be used, as well as speakon AND regular speaker wire. To me this was a big plus, giving me lots of options. They had just released the Gen 2 models, and being budget minded, after seeing that the differences were small and IMHO not worth opting for the newer model, the decision was made to go with a XLS Series 1 amp. Additionally, after seeing the XLS2500 bench tested
, its specs were fairly inline with the manufactures published specs. This put to rest the main unknown about Crown amps in a HT setting, which was if they had implemented a 12db per octave filter in the amp starting at 20 Hz. You could read responses online from folks stating one way or the other, and I even contacted Crown myself and was told there was one there. The bench tests proved otherwise.
Problem: no programmable DSP in the Crown XLS
The problem with the Crown XLS series was that it was missing the ONE feature the iNuke DSP line had that I considered of value, and that was a programmable software based DSP. While XT32 in my Denon did a decent job of calibrating subs, The OCD basshead tweaker in me, wanted to install some shelf filters to attempt to lower the F3 of my boxes, or just add some sub 20 Hz boost. Neither of which the Crown had by default.
Solution: Aftermarket DSP, which to choose
That flaw lead me to look at existing options to add DSP to the equation for not a lot of money. The options I saw were the Antimode, SMS-1, MiniDSP and AS-EQ1. The Antimode and AS-EQ1 were removed from the running as they are mainly automatic EQ’s and wouldn’t not allow much customization. The SMS-1 lost out in that it just didn’t have nearly the feature set that the MiniDSP had.
The MiniDSP I needed was the 2x4 balanced. The Mini-DSP is the REAL reason for this thread.