MACH 18.2.2 IXL SUBWOOFERS

DUAL MACH 18 IXL SUBWOOFER BUILD
$$ SOLD $$

Some may think owning Dual 18inch subwoofers is close to are crazy in a residential environment. 

Well I say you haven't heard bass until you have experienced the depth, speed and impact of large diameter/piston drivers. Nothing will prepare you for the sheer weight and authority of a large diameter bass driver, especially when compare to today's small and compact subwoofer solutions.

IST Mach 5 UXL-18 18" subwoofer - Click Image to Close
Picture from: affordabledrivers.com.au
The purpose of this blog post is to briefly detail the build of my Dual Mach 5 18.2.2 18inch subwoofers. I hope this information aids other budding DIYers to give it a go. 

Alot has been said on the web about the Mach 5 18ixl drivers, and there's good reason why. 

The Mach 5 18ixl drivers I selected offer incredible value for money, and have only recently been replaced by Mach 5's new IST Mach 5 UXL-18 18" subwoofer, an incredible driver to say the least. 

I built my subwoofers with the following end goals in mind: 
  1. I wanted subwoofers that would dig deep for movies, and have excellent transient response 
  2. They need to be musical when listening to hifi, and exhibit no overhang or obvious group delay.
  3. My subs needed to be powerful and capable of handling 800watt-1200 RMS each for bass impacts during movies and musical transients. 
  4. The cabinets needed to be manageable, and have some WAF. Although these cabinets are not small and still unfinished in raw MDF, they are not HUGE like some other LTE/subwoofer designs.

CABINET DESIGN 

The software I used to help design the cabinet size and tuning was WIN ISD Design. its free & found here:  WIN ISD Linearteam Design 

After settling on the "maximum box size" I could manage in my space, WINISD quickly gave the following parameters for my design. You will notice I give both sealed and ported alignments here. That's because I designed the subs to be ported for movies and sealed for music (via port foam bungs). 

Internal Volume:  Circa 167litres 
Internal Volume Less brace/Ports:  140litres 
Weight:  Lets just say the are bloody heavy
Ported Alignment tuning:   24HZ -3db free space in estimated 140litres (White  Trace) 
Port length: Dual 100mm ports @ Circa 47cm, with end correction 
Sealed Alignment:  0.646 (Yellow Trace) 


Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio



MACH 5 18.2.2 DRIVER FEATURES

Below you will find the driver specifications for the Mach 5 18ixl, taken from the Affordable drivers websiteThis is where I purchased the drivers. 
  • High quality, ultra-low distortion, long-throw 18" subwoofer suitable for home and car audio
  • Heavy 6-spoke cast aluminum basket
  • 3" dual 2 Ohm voice coils (can be wired in series to produce a 4 Ohm load or in parallel for a 1 Ohm load)
  • Thick pulp cone with heavy foam surround
  • Wrap-around rubber gasket
  • Vented pole
  • Triple stacked motor
  • 75mm four layer voice coil
  • 2 layer spiders
  • Suitable with amplifiers of up to 800 watts RMS
  • Plain dust cap (no logo)
  • Twelve months warranty
Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
Mach 5 18.2.2. 18IXL Side View
Cast Basket and massive Magnet Essembly
Picture from: affordabledrivers.com
Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
Mach 5 - 18ixl - 18.2.2 Driver Rear 
Picture from: affordabledrivers.com


PARAMETERS

  • Power handling: 800 watts RMS
  • Sensitivity: 89db (2.83 volts) - coils wired in series (4 Ohm nominal impedance)
  • Impedance: 2 + 2 Ohm (DVC)


DIMENSIONS

  • Outside Diameter: 46.2cm (18 3/16")
  • Mounting diameter: 42.4cm (16 11/16")
  • Depth: 24.8cm (9 3/4")
  • Weight: 16 kg


T/S PARAMETERS

  • Fs: 17.7 hz
  • Re: 3.4 ohms
  • Qes: 0.39
  • Qms: 5.59
  • Qts: 0.37
  • Mms: 434.3 grams
  • Rms: 8.69 kg/s
  • Cms: 0.184 mm/N
  • Vas: 274.1 litres
  • Sd: 1029.2cm2
  • Xmax: 22mm (one way linear). Xmech is limited only to the depth of the spider landing of the basket which exceeds 30mm
  • Cone Diameter: 36.2cm

LISTENING 
Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
Leon appreciates
good bass too!!

First thing is first, how do they sound? well pretty bloody amazing! 

Believe it or not, these DIY subwoofers sound more musical due to their extended frequency capability than my Dual (Yes 2) $4500 Velodyne dd10's. If that is not saying something for DIY Speaker building I don't know what is. 

On movies these subwoofers have jaw dropping performance. They run rings around any brand name subwoofer I have heard upto $6000 in value. They move serious air, and have the ability to compress my large 8x7 meter listening room (which has 2 stairwells with free space) with ease. 

Just the ticket for high impact movies. 

On War of the Worlds, when the alien robot machine comes out of the ground, these subs exhibit serious power handling. Lesser subs including my Velodynes at reference levels digitally compress/bottom out on this scene, due to the huge amount of low end information present and the SPL required to reproduce at reference levels. 

These subs handle 800-1000 watt RMS loads with ease in ported mode, producing the most amazing and clean low end extension I have heard from a subwoofer solution to date. They cruise through high energy action scenes, with immense power, impact and pose. 

Truly exceptional subwoofers!! 

Their transients and impact delivery is flawless, due to their massive motor travel and rigid surround. On music in sealed mode they are "VERY" fast and hit with pose and speed. I have run them up to a crossover point of 60-80hz and they deliver sound quality on par with my Velodynes. 

Considering these drivers cost me $320inc gst, plus time and MDF, its a non brainer for the DIYer looking to achieve top tier subwoofer results. Just remember to include the cost of an amplifier into your mix. 

Commercial PA amplifiers such as the Behringer EP2500, Crown XT, etc offer the best value for money here. Preferably look for amplifiers with DSP capability for room equalisation and tuning, if your digital processor doesn't offer this functionality via Audessey XT32 or similar, room acoustics can be difficult to overcome otherwise.    

Key selection criteria should be: 
  • Power Output @ correct impedance load
  • Current delivery capability 
  • Dampening Factor - The higher the better, over 1500 is preferable for tight bass & good piston control
  • Quite Operation / Fanless if possible 
I wont elaborate any further on this, there is ALOT of information of the web about amplifiers solutions, from far more technical people than I. 



BUILD PICTURES 

This was my first Hifi DIY speaker build of any kind. 
I have previous experience with 3-4 automotive subwoofer and speaker solutions.   

Construction of the cabinets was completed with very basic tools. The main tools utilised were: 
  • Square
  • Circular saw - But not really utilised 
  • Hand saw 
  • Router & Router bit set 
  • Clamps 
  • Electric Drill & Drill Bits 
All wood was cut with a hand saw, as I found it more accurate than my Ozito circular saw. I used a router to finish and square the edges, to cut the driver opening and flare the port holes. I recommend a good router for any DIY speaker build, such a versatile tool. 

Photos in a circa timeline order.... 



Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Here you are looking through the box, from a side view. The 4 sides form the front/rear, top/bottom of the box. I inserted a temporary piece of timber to help keep the box square during glue curing...  I leave the sides last.... Allows me to insert all timber framing and port work... 

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Timber ribbing/framing inserted to effectively create an enclosure with 40mm sides... The ribbing gaps are approxmiately 150-200mm apart... 
Ribbing is glued with PVA and screwed in place from the outside of the box. 

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
Driver hole is cut with a router... 
Port cutouts are marked and next to be cut with a 100mm holesaw


Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
ALL MDF ribbing runs front to rear of enclosure. 
This method of reinforcement creates a very stiff front baffle and an inert enclosure. 

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

100mm PVC duct was used to create the speaker ports.... 
Tuned to approx 25hz -3db....  The end sections of the ports are removable for tuning alteration/customisation. 

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Tuning ports were simply glued in at multiple points.
Once the PVC and liquid nails cured, they were rock solid.... I could lift the cabinets holding the ports!!
Some builds I have seen on the web go to overboard.

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
A good photo detailing the cabinetary ribbing/bracing. 
Additional bracing was inserted to brace the side walls to each other and the rear wall. 

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Once the ports were installed, I ran the router around the 100mm hole against the  PVC diameter to provide a perfect flared opening.  Quick and Easy!

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Drivers installed.

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
Notice the foam port bungs on the right subwoofer
These allow for a sealed alignment as required
I run the woofers in ported mode for movies, and sealed for most music...
Even in ported mode these subs never sound boomy, they are quick and extremely dynamic.

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio

Compact 18inch enclosures...

Mach 5 ixl 18.2.2 18 inch subwoofer 2channelaudio
Ready for a paint & amplifier connection.

2 comments:

  1. I see you've sold the subs. Do you miss them or does your new speakers pump enough bass?
    I'm thinking about buildning a pair of subs I have deep clean TL bass now, woul just want some input from you on what you think?

    ReplyDelete
  2. Hi there Fx,

    I have only just fired my speakers up in the last week.
    The drivers are currently running in and I am only just beginning their tuning process, so its too early to make any assumptions or comments,

    Obviously nothing beats a great subwoofer for bass, so no my speakers don't have the bass output of two large 18inch drivers, but they do have ample extension "thus far" for music listening in my room. (The woofers are still very tight and its too early to make any board comments about the builds bass performance at this stage.)

    I will say that I miss the fantastic and effortless bass extension the 18inch woofers and/or my dual velodyne subs bring to the table. But for now I am happy to use my speakers as is with their 12inch drivers and implemented BSC equalise curve.

    If I happen to opt for more bass extension later down the track, I can easily equalise the 12.5.1 setup for a little more extension (as my drivers have 10mm one way xmax) or build a complementary subwoofer or replacement 15inch bass cabinet.....

    Time will tell !

    Fx, my advice is try and get your hands on a friends subwoofer and try it in your system.
    See if you like what it offers........ Best to try first.

    But I think most HiFi subwoofer owners would agree, a well designed sub or 2 should provide welcomed extension and musical gains for any floor standing or bookshelf system.

    Let me know how you go.... What TL?s do you run?
    2CA

    ReplyDelete