Dual Maelstom-X Ported Sono Build Thread

My house hates me..............

Well, I couldn't wait any longer. I wired up and installed one of the Mals today and hooked it up on one channel of the EP2500 and laid it on its side (feet not on yet). I played it easy for about 15 minutes doing a quick ear tune. Then I decided I wanted to play some test tones. Started at 15Hz and then went up in 1Hz increments after that. I was playing with the level to see what kind of crying my house was going to do.

Now mind you, I am testing these out in my finished basement "bass cave" where I currently test all of the subs I build (not the final location for the subs). In the basement I have a Harman Kardon AVR510 receiver hooked to two Electrovoice ZX1 commercial speakers, a JVC dvd player, an MCM unbalanced to balanced converter, an Elemental Designs EQ.2, and an EP2500.

The house was built in 2005 and is pretty sturdy. I heard it making noises I never thought were possible. I was easing the levels up on 15-20Hz and the drop ceiling tiles in the basement bathroom were levitating! My poor laundry room shelves have emptied themselves of all of the detergent and folded clothes. The basement windows are flexing in and out and sqeaking like they want to burst.:yikes: I went upstairs and the floor was shaking so bad that if you stand flatfoot, your eyes go blurry. Needless to say the output is intense, and this is one of the two! I was able to reach the limits of the EP2500 in stereo. It clipped a few times.

The only concern I have is a slight chuffing from the port on some frequencies:scratch:. Not sure what is going on there. It is slight, and maybe I wont hear it when I eventually stand them upright. Any ideas?

I can say that I am very impressed with the output of these Mals in this configuration!:hsd:

I will keep updating as I finish the other and put it all together and EQ it.

Sounds like you have enough output. :flex: Just imaging what the 21" will do with another 40-50% more cone area. The port chuffing will probably not be an issue once you are in the room listening to program material. It is always bad with test tones. Much less of an issue with actual movies/music.

Yea... be careful with test tones. Most of the heat dissipated from a coil is done via convective heat loss. That means that air has to be moving over it. When you get near the port tuning frequency, you will notice the driver's motion drops significantly. That is the danger zone because you may be pushing large amounts of power into the coil and the driver is no longer pumping air across it for cooling.

The Maelstroms have held up very well. I've not seen a thermal failure yet but you don't want to be the first.

Kevin Haskins
Exodus Audio

thebuckaman said:

I am able to clip the EP2500 on music fairly easily. I am wondering if my wall AC is getting taxed too much? I am going to EQ the subs soon after I get them upstairs into the living room. I am thinking of another EP2500 too. Will I have to run a dedicated outlet to them? If so, it will be very difficult.

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Here's how I would check that out. Pick a test tone in the lower range which tends to take alot of power to produce. Establish the max volume you dare play, without letting the sub play more than a few seconds at a time. Next, measure line voltage (meter plugged into the same circuit as the sub amp) with the sub off as a reference. Leave the volt meter set up where you can read it. Then, play the test tone at a level which is as loud as you dare. AS mentioned earlier, you must be careful with this but if you just let it run for a few seconds then take your reading, then turn the test tone source off you should have a fair reading. All you are trying to do is get the amp's power supply to a point where it's at equalibrium, not just a quick hit supported by the caps (if it is going to sag you want to see the sag). This is the procedure, what you are looking for is a drop in voltage, I've used this for car audio as well. So your question is going to be, what is acceptable? Maybe others here can help with that. But do know, that sag in the voltage equates to heat in the wiring.

With good wiring and proper breakers, it's tough to get it to sag much without tripping a breaker, at least without extended playing (the breaker will heat).