Project Quick, Easy & Cheap IXL18.4 LLT - Home Theater Forum and Systems -

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post #1 of 15 Old 08-04-08, 09:03 PM Thread Starter
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Project Quick, Easy & Cheap IXL18.4 LLT

I've had a request to document my build of my LLT IXL18.4 on HTShack.

As such here are the details:

I’d like to start off and thank Neo Dan on his thread “IXL 18 meets the ‘Easy Button’ ". This feed one of my objectives which are mentioned below and was my inspiration for this project.. After talking to SteveCallas further I was convinced this would be a perfect little project with some minor modifications to suit my requirements for the build.

.:My Objectives/Requirements:.

As much as Neo Dan’s design is “simple” I wanted to refine it even further, making it even simpler. Less cutting, etc.

My second objective was cost. I wanted to get into the LLT game without spending a fortune. SteveCallas helped me solidify this decision. Thanks.

My last objective was around mobility of materials for construction. As I don’t have a truck or access to anyone with a minivan I wanted to be able to haul all parts/materials with my car.

.:Core Materials:.

1 18” Mach5Audio IXL18.4: Currently one of the best bang of the buck subs available. This facilitated the cost objective. There are very few drivers that even close to this price tag ($235 shipped) and deliver similar performance with as much displacement.

Leaning on NEO Dan’s design I liked the use of MDF over a SonoTube for 1 reason only. Mobility. Back to objective #3. I can transport planks of MDF easily within my car, putting the seats down. A 24” sonotube unfortunately wouldn’t fit.

.: Design Considerations :.

Back to the whole “make it easier” objective. My local Home Depot sells pre-cut 48x24 (Actually 49.5x24) sheets of ¾” MDF. Although I own a table saw, having the wood precut with precise measurements IMHO is a head start. Less work of me having to cut them precisely myself + no MDF dust cleanup. Bonus..

I'll need 7 49.5x24 sheets:
  1. 4 for the outer sides of the enclosure
  2. 1 for the driver baffle (Have Home Depot cut this 49.5” long plank twice yielding 2 22.5x24”)
  3. 1 for the internal bracing (Have Home Depot cut this 49.5” long plank twice yielding 2 22.5x24”)
  4. 1 for the port baffle and base that this enclosure will rise upon (Have Home Depot cut this 49.5” long plank twice yielding 1 22.5x24" and 1 25.5" x 24")

In and out of Home Depot in 10 mins. Piece of cake, no cutting, no having the wife complain about asking her to “hold the MDF” as I run it through the table saw.. You get the gist..

I'd also like to mention that Mark at Mach5Audio is second to none in customer service. The first IXL I received 8 months ago got wrecked in shipping. I didn't realize this until when I was installing it just a few weeks ago. Mark was quick to remedy the problem sending me another driver express shipping. Unbelievable service to say the least.

Last edited by myn; 08-06-08 at 03:51 PM.
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post #2 of 15 Old 08-05-08, 05:46 PM Thread Starter
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re: Project Quick, Easy & Cheap IXL18.4 LLT

.: Quanative Figures :.
  • Vb 13.34 cu ft
  • Total (excluding items displaced) 15 cu ft
  • Fb 14.48 hz (tuning freq)
  • F3 25.33 hz
  • 3 4" x 34 Ports
  • No damping

.: Box Volume Displaced By :.
  • Port displacement .918 cu ft (internal)
  • Bracing / double baffle .373 cu ft
  • IXL18.4 driver .365 cu ft

.:SketchUp Design:.

Last edited by myn; 08-05-08 at 07:00 PM.
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post #3 of 15 Old 08-05-08, 05:47 PM Thread Starter
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re: Project Quick, Easy & Cheap IXL18.4 LLT

.: Finish :.
  • 1/4 round over on all edges
  • 8 cans of flat dark grey primer then sanded with 220 and applied 15 cans of Duplicolor Truck Bedliner. Just a quick note on this product. It is very temperamental. It really sets/dries differently depending on the temperature and humidity level. I actually had to go back and redo the top of the enclosure because I sprayed it on a different day with a different climate temp/humidity level then rest with of the enclosure giving it a completely different very harsh sandpaper finish. To make a long story short, I did a lot of sanding and bondo resurfacing the top to make it nice and flat so I could try again. A lot of extra time however it was definitely worth it as the finish looks consistent now. Also, this bed liner contains 2 ingredients that promote cancer.. With that said, use a respirator.
  • 5 1/4" black snap on grills from Parts Express were used to cover the 3 4" ports"

.: Construction Notes :.
  • 4" Black PVC Pipe (4.5" total diameter including port walls) From Lowes
  • All joints were glued together using TiteBond II with clamps (no screws)
  • Liquid Nails (Project) to seal interior enclosure and secure port to internal bracing
  • Flush trim router bits are your friends if you are "off" a slight margin in your cuts as they eliminate hours of sanding
  • 4.5" long x 2" Dowel used between driver baffle and base. (Lowes sells 2" Dowel. My HD's largest diameter sold was 1.5")
  • Can the IXL18.4 be oriented in a down firing orientation? Yes.. (see below)

    According to Parts Express, here's the formula to calculate sag: Percentage of Sag = 24,849 / ( Xmax * Fs²)

    Sag% = 24,849 / (22 * 17.7^2)
    Sag% = 24,849 / (22 * 313.29)
    Sag% = 24,849 / 6892.38
    Sag% = 3.61

    Sag is less that 5%. The IXL18.4 is fine for down firing.

Last edited by myn; 08-05-08 at 07:46 PM.
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post #4 of 15 Old 08-05-08, 05:47 PM Thread Starter
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re: Project Quick, Easy & Cheap IXL18.4 LLT

.:Power/Signal Processing:.
  • Summary: Panasonic XR55 --> BFD --> EP2500 --> IXL18.4 LLT
  • Behringer EP2500 running Bridged Mono
  • Behringer BFD
  • CleanBox (Used prior to BFD arriving. When I introduced the BFD, the CleanBox was no longer required)
  • RCA Line out to RCA Jack To 1/4" Mono Plug Adapter -->

.: Hardware :.
  • 1/4-20 Hurricane Nuts (from PartsExpress) attached to the rear of the baffle and reinforced with gorilla glue.
  • 1/4-20 2" Socket Cap bolts from Micro Fasteners [great prices, cheap shipping] (Lowes and HD only sell short socket cap's <= 1.5")
  • Assorted length course threaded drywall screws to secure 2" x 4.5" dowels to baffle and base

.: Equipment :.
  • Skil 1825 Router (WilllyD's recommendation) This thing had no problems going through 1.5" MDF (dual ply .75") doing the baffle cut out. using a 1/2 x 1.5" straight router bit
  • Black and Decker Jigsaw
  • Cordless Screwdriver
  • Assorted smaller spring clamps, Pipe Clamps, Square Clamps, The more the better... Of the local shops, Harbor Freight was consistently the cheapest for clamps
  • DIY Circle Jig [1/4" MDF]

Last edited by myn; 08-06-08 at 03:58 PM.
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post #5 of 15 Old 08-05-08, 05:48 PM Thread Starter
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re: Project Quick, Easy & Cheap IXL18.4 LLT

.: Photos :.

Driver arrived

Finite Dimensions

Hurricane nuts secured by gorilla glue (a must)

I <3 Liquid Nails. It really provides a great seal and has no problems binding PVC to MDF in a secure fashion

Having to redo the top after having sprayed the bedliner on the rest of the enclosure Lotsa Bondo and sanding!

My Dip switch settings

The center tabs on the Behringer EP2500's speaker terminal plugs are removable allowing banana plugs. I am running mine in bridged mono.

Last edited by myn; 08-05-08 at 07:53 PM.
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post #6 of 15 Old 08-05-08, 05:49 PM Thread Starter
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Re: Project Quick, Easy & Cheap IXL18.4 LLT

.: Videos :.

Here's a video of my 3300 sq foot house vibrating/rattling while playing a 20hz tone at a conservative level. Note this was taken outside of my master bedroom in a completely different room from where the HT is located:

Mach5Audio IXL18.4 20hz - rattling the house

Mach5Audio IXL18.4 20hz - close up

Mach5Audio IXL18.4 20hz - More Rattling

Last edited by myn; 08-05-08 at 07:01 PM.
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post #7 of 15 Old 08-05-08, 07:45 PM
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Re: Project Quick, Easy & Cheap IXL18.4 LLT

Thanks for posting your build, myn. The box plans make it easy for anyone to duplicate your build. Great job!
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post #8 of 15 Old 08-06-08, 12:18 AM
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Re: Project Quick, Easy & Cheap IXL18.4 LLT

Got any REW results yet? Looks good!
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post #9 of 15 Old 08-06-08, 01:58 PM
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Re: Project Quick, Easy & Cheap IXL18.4 LLT

Nice build. What do you think of the sound so far?
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post #10 of 15 Old 08-06-08, 03:45 PM Thread Starter
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Re: Project Quick, Easy & Cheap IXL18.4 LLT

Coming from the car audio scene I always wished I could get a low end monster this size (14 cu feet) into the trunk. With this being the lowest tuned ported subwoofer I have built I can honestly say I'll never go back to tuning higher using a smaller enclosure in any application. Anything less would be a compromise.

This IXL LLT effortlessly cranks out the low frequencies without any audible stress on the driver however the walls and foundation are definitely feeling stressed let me tell you. (see videos above) I used to think my Bass Mekanik Bass CD's got low. This was the case until I poped in WOTW and Transformers and discovered there is an entire lower layer of bass that my previous subs were unable to reproduce. Much more tactile than audible but definitely necessary . I have a new found craving for subsonics.

So to answer your question, Yes I am very happy with both the SPL and SQ. It's a very nice balance. SQL at it's finest .

I haven't taken any measurements yet. Infact I still need to find a cheap external sound card so I can get going with REW. Got any suggestions?

So far I've used the BFD more as a crossover. I created a filter set in 1/6 oct increments that negated (-48 db) all frequencies above 67hz emulating a steep lowpass crossover. My Panny XR-55 LFE crossover only dips down to 80hz (12db slope) which IMHO is way to high. I could still hear voice in the sub so this fit the bill perfectly. It also opened up some more bandwidth down low as the sub no longer needs to produce the upper-low bass (67-80hz). I also added a couple of medium wide filters in the 30 - 50hz range adding a tiny bit of boost that I thought was missing due to the room acoustics. Again, this is all by ear.

Once I get a soundcard I'm going to take some measurements and completely set the sub up with a nice little house curve but for now with no measurements it sounds really nice.
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