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6,337 Posts
Discussion Starter · #1 · (Edited)
Martysub is a ported subwoofer with a slot port. Its not a new design but it has become very popular for several reasons :

1) easy to cut and good use of a sheet of mdf or Plywood.
2) powered by inuke amp which is dirt cheap
3) using si18d4 allows huge spl from inuke3000dsp .

Lots of other reasons as well. The first post covers from start to finish of the cab. Post two covers hooking up to your system and optimizing. The third post will have pics of various subs. Most of the info here will be for any ported sub. If you want to contribute to the FAQ just pose a question with the answer and if helpful I will add it. It will take a few days to flush out the info.

The whole Marty line of subs were designed by LTD02. His tireless patience helped me when I was a noob and has helped hundreds of others. John took some of the design from NeoDAN. Who is neodan ? Many years ago, there was a forum member, neodan, who created a line of subwoofers that he called the "easy button" subs. they were meant to be large, low-tuned, bang-for-the-buck type subs. when we cooked up the design for the original martysub, I had long forgotten about the "easy button" line. upon rediscovering his subs though and how similar the martysubs were to his, I feel that he should get some sort of mention. here is one of his subs:

Hopefully this thread will be a spot for people either interested in starting a sub or answering those questions to help you finish. Also a general spot for Martytalk ! Who is Marty .......

1) What are the standard sizes with SPL chart

Microcube - green
volume = 3.75 c.f. , tuning = 23hz Dayton 390ho with 1100 watts

Martycube - red
volume = 4.75 c.f. , tuning = 20hz
si 18 1100w

Minimarty - blue
volume = 9.0 c.f. , tuning = 18hz ultimax 18 2000w**

Full Marty - black
volume = 11.0 c.f. , tuning = 17hz uxl18 2200w**

**might want to limit the ultimax to 1200w or so until it gets proven out. uxl iirc suggested amp power is 2000w max.

Here shows the difference in output of drivers in same cab

1a) Why not just build sealed subs. Easier to build ?
They are easier but the large ported subs simply offers the most bass for the money if you have the space for the large enclosures. not everybody does and not everybody cares about bang for the buck. it is all a tradeoff. the martysubs generally trade off larger size for more bass at the lowest possible cost while remaining a relatively simple build. Here is comparison with same driver with 1100 watts in a sealed cabinet (blue) vs. a martysub (red)

If you want to model yourself here is how

Grab a copy of winisd. if using windows 7, go here: https://www.facebook.com/Winisd

Enter thiele small parameters for a driver (aka t/s specs):
make sure all fields are clear, then
enter qes then hit tab, enter qms
hit tab a couple times and let it calculate qts
hit tab a few times to move to mms
enter mms, re, bl, le, sd, xmax, and pe
by using tab after entering each data, it will calculate what it needs to
i no longer get any conflicts
sometimes the specs calculated don't match exactly the manufacturer specs, but its only rounding type errors, so it is not material

2) What are the sizes of the four standard Marty's ? Can they be adjusted to fit my room ?

You can customize the size to fit your room as long as the cuft stay close. Minimarty could be 2' by 30" by 36". The minimarty and full can lay horizontal as well. If the internal volume of the sub is kept the same, and the cross-sectional area of the port is kept the same, and the length of the port is kept the same, then the sub will pretty much perform the same no matter what shape you cook up, which way the port fires, or which face of the sub you mount the driver on. If you choose a full size marty with ~11 cubic and a slot port that is 3" tall and 22.5" wide (24"minus to slot braces at 0.75" each) and 36" long, the cross-sectional area of the port is 3" * 22.5" = 67.5 square inches. so if you want to make the port 18" wide, then it would be 67.5 / 18 = 3.75" tall x 36" long. If the port is an inch or two too long or too short, it won't make a material difference.

3) Which Marty for me ?
I get asked this a lot. Everyone's bass needs (yes its a need not a want) are different but here's some general guidelines. For a small room under 1500cuft a pair of the micro and cube are potent. In a medium size 1500-3000cuft a mini and a cube are good. In a large over 3000cuft room a pair of mini/full are really good. Bigger is better so try to convince the rest of your family that you need a fridge in the living room

For tactile feel I recommend having one nearfield . I have a micro a foot away and it rumbles my seat at 90dbs.

4) Which drivers can I use ?
The micro is very small ported box and doesn't have a lot of options. I use this
Could also use Eminence Lab15. Any other 15" driver that will work in 3.75cuft cab.

Cube has lots of options
Here are some
The 18" has single voice coil and dual voice coil. For wiring options the D4 (dual) is better. You can use the 15" model as well. The lose a couple of db's.

The Dayton and Si measure very close. Dayton can handle a little more power.
The uxl18 is a beast. Its pricey but gives you 3-4dbs more then Si/Dayton. Can use there ixl18 as well.

The Minimarty/Full cab can use all of the subs in cube as well as
The ultimax is new and we haven't seen many builds with it yet.

Should I get Stereo Integrity D2 or D4 if there is an option?

It depends on the amp. many folks run the inuke 3000dsp or the 6000dsp. the 3000dsp can handle a 2 ohm load per channel (that's really pushing it, but it can do it) and the 6000 can handle a 4 ohm load per channel (again, that's really pushing it, but it can do it).
With the 3000dsp, the d4 drivers are a good choice. each driver can be wired in parallel for 2 ohms. and then one driver connected to each channel. the amp will supply approx. 1100 watts or so to each driver in this configuration.With the 6000dsp, the d4 drivers are again a good choice because they can be wired in series for 8 ohms per driver. one driver per channel produces about 1100 watts to each driver. HOWEVER, this configuration is much less taxing on the amp. If you are only going to get one driver, and want to run the 3000dsp, grab a D2 and wire it in series for 4 ohms. then run it in bridged mode on the 3000dsp. that will give up to 2200 watts (which you can back down to 1100 with the limiter). HOWEVER, this configuration is much less taxing on the amp than running one driver on each channel at 2 ohms.

5) What is tuning ?
Tuning is where the subwoofer will drop off significant in spl. Music rarely goes below 25hz (pipe organ or bass track being exception ) but movies go much lower. Lots of debate in how low you need to cover but if you only have two subs then 17hz tuning is near bottom of what you need. You will get good output 3-4 hz below tuning usually . Low tuning for a ported box needs space. That's why full Marty is lowest tune.

6) Ok , I know which cab I am going to build , what tools do I need ?
You will need something to cut the wood. A skillsaw works fine with a straight edge. Tracksaw is even better and a tablesaw is the quickest. You will need :
* a jigsaw/router to cut the driver hole
* drill to screw down driver ( could get away with screwdriver but more difficult)
* clamps (3' and 4' depending upon cab)

A Brad nailer/compressor is great to have and really speeds things up. Also I recommend a router to flush trim edges. Also a orbital sander saves your hands wear and tear.

If on a budget its hard to beat
http://m.harborfreight.com/?utm_referrer=direct/not provided
For clamps there awesome. Lots of differing opinions on what brand of tools to buy. My personal opinion is you can go cheap on clamps , jigsaw and palm Sanders. Skillsaw , routers, and nailer its good to at least get medium price level.

You will need glue. Most use Gorilla glue (original expands)or titebond (the different versions have different working times). For filling small cracks or holes this works great

For large cracks/gaps construction adhesive is good.

7) I have the tools..... Just give me the damn cutlist !

Here is a program for layout on sheet to maximize cutting


8) How do I build these babies ?

Here is simple build of vertical minimarty

Here is my youtube channel with video in sections

I generally build this path
* attach sides to bottom
* attach back to bottom (put baffle in to square up without glue)
* attach port bottom rails and then port bottom
* attach port back rails and then port back
* install bracing and then foam
* install baffle and then top

9) What about Bracing ?
Good question my young woodworker. There are several ways to do it. Some like a series of dowelling

while I find window bracing the easiest . A window brace is this

A general guideline is to have crossbracing at least every 10". The micro and cube use one crossbrace. The minimarty needs 2-3 and full 3-4.

Will show a completed bracing pic soon

10) What about lining and filling the inside ?

A ported subwoofer does not need filling with pillows but the walls do need lining. A good choice is a foam bed topper

Walmart have them cheap. Cover the walls but don't block the port. I use spray adhesive to attach

11) Is my options for a finish of the cab limited to paint ?
Nope ! There are three main ways you could finish your sub.

You could paint it regular latex paint. (Downfiring cube)

Second is to duratex it.

Lastly you could put a nice veneer and stain it.

6,337 Posts
Discussion Starter · #2 · (Edited)
This second post starts with you now having finished the build process and connecting it to your system.

1) What cables and connectors do I need ?
Because we are using pro amps(discussed more later) we need to use speakon connectors and cables. Lets start at the sub and work our way back from there. You will need 12 or 14 gauge speaker wire to go from sub terminals (wiring coming later) to speakon connector. Wire like this is good http://www.monoprice.com/Product?c_id=102&cp_id=10239&cs_id=1023902&p_id=2748&seq=1&format=2 I get all my wire and cables from monoprice or ebay.

Their are a couple of different speakon connectors that you can get but I prefer this one https://www.parts-express.com/neutrik-nl4mpr-speakon-connector-4-pole-round-chassis-mount--092-054
It allows more leeway when drilling the hole and it has 4 pole which allows bridging. The hole needed to mount this is 7/8". You can mount it anywhere really but most prefer to put it on the back or side. If you put it on the back it doesn't effect the port. Just drill through the back wall and the port back wall as well.

From the connector you need a speakon cable to go to the pro amp. I use monoprice and you just need to get the distance that your sub is from the amp. If you need to cover 8ft then get this one
You can make your own speakon cables but monoprice is so cheap I never bother.

Next you need a cable that goes from the pro amp to your avr receiver or processor. This cable will depend upon what you have in terms of xlr or rca. Both cables are on monoprice. Here is balanced or xlr http://www.monoprice.com/Product?c_id=115&cp_id=11509&cs_id=1150902&p_id=4750&seq=1&format=2 Typically 3' is enough if you have all your av equipment in the same location. If their not you may need longer. If your avr has rca output for subwoofer then you will need one of these http://www.monoprice.com/Product?c_id=115&cp_id=11509&cs_id=1150902&p_id=4776&seq=1&format=2
If you are running dual subs from a single rca output from your avr you will need this to connect this to the last cable

Ebay and other online stores have them.

2) Which amp do I need ?
The amp you need is dictated by the driver mainly and spl you want to hit. Budget conscious people ( that's me :) ) will tend to gravitate to the inuke series of amps by Behringer. They are not the only ones however. Crown, Peavey, and others make a powerful amp. The two most used amps seem to be the inuke3000dsp and the 6000dsp. They both look like this

Not an attractive amp but gives you thousands of watts for the price. The 3000 model will put out around 650 watts in stereo mode 4 ohms and 2200 watts in bridged mode. The 3000 however can be wired for 1100 watts stereo with a dual voice coil sub like the si18d4. The 6000 will put out around 2000 watts in stereo mode. You cant run bridged more with 6000. Both amps have limiters to dial in an exact amount. Ignore the wattage stats on behringer specs. (their inflated). The dsp gives you a hpf (high pass filter) which is needed for a ported sub. (more on that later) It also gives you delay, peq and deq. They sell the amps without dsp but I recommend getting it. Even if its only to make it easier to sell in the future. As for which amp to get , if your not really tight for cash I recommend the 6000. You never know when you will get different subs and its nice to have your power needs covered. You can buy this amp from ebay, amazon, Guitar Center, etc. These are D class amps that are light (10lbs) and easy to use.

The downside of these amps are appearance (they can be painted ... http://www.avsforum.com/forum/155-diy-speakers-subs/1527053-painting-your-inuke-aka-black-berry.html) and noisy fan in behringer amps. Fan mods can be done but depending upon how you do it , can void your warranty. Here's the fan mod

3) Wiring is soooooooo confusing... sometimes I feel like this

I'm going to show some of the common setups. A great website for help is http://www.the12volt.com/caraudio/woofer_configurations.asp

A) single sub in various setups
1) Can run in stereo. Stereo is red (1+) black (1-). Ignore 2+ and 2-. With 3000 dsp this gives you 650 watts. 6000dsp gives you 1800 watts. Use input A on amp.

2) Bridge mode is red (1+) and black (2+). Ignore 1- and 2-. This is only for 3000 inuke and gives you 2200 watts. 6000 inuke can't be used in bridge mode. Use input A on amp.

3) Bridge mode for si18d4.
Same 1+ and 2+ as above but also run a jumper from pos to neg of second voice coils. This gives you 1100 watts which is perfect. Use input A on amp.

B) two subs in various setups
1) two single coil 4ohm subs in stereo. 3000 is 650 watts and 6000 is 1800 watts. Same wiring as A1 with both input A&B used on amp.
2) two si18d4 subs .

This is for 3000 amp and will give you 1100 watts to both drivers.

4) How does speakon connect in stereo and bridge mode and how do I change it ?

When running one driver on each channel in NON-BRIDGED MODE, 1+ and 1- will be used. 1+ gets connected to the positive/red on the sub and 1- gets connected to the negative/black on the sub. in NON-BRIDGED MODE 2+ and 2- are NOT used.

When running the amp in BRIDGED MODE, 1+ and 2+ will be used and the cable will go in Channel A. the amp must be set to "bridged mode" (this effectively reverses the polarity of the 2+ terminal into a negative but instead of 0/ground voltage it produces the 'negative version' of what is going to the positive terminal thus doubling the overall voltage output, which increases power by a factor of 4). 1+ goes to the positive/red on the driver and 2+ goes to the negative/black on the driver.

***** This applies to the connector and the cables *****

Here's a video of how to change speakon cable

5) I have sub built, wired up, can I fire it up ??????
Nope. your almost their but not quite. You don't want to damage your new baby so lets use the DSP of the inuke. You need to set the hpf for your ported subwoofer. The high pass filter job is to filter out the frequencies BELOW the filter point and allows the frequencies ABOVE the filter to PASS. that is why it is called a HIGH PASS. In a ported cab, below the tuning frequency, the cone motion is acting more or less as though the driver is in 'free air'. there is very little resistive force on the driver and it will flop around all over the place creating massive distortion and potentially damaging itself. This is cone motion of the subs shown above. Note below about 16hz cone motion shoots through the roof, goes way past xmax, and could be damaging.

Here are the same drivers with a 16hz high pass in place:

With the protective high pass filter in place, the cone motion no longer explodes and the system remains well behaved even at extreme output.

The HPF setting should be the tuning setting for the cab you pick. For the minimarty and full marty that means around 17hz. The behringer lowest stock setting for hpf is 20hz. The best starting slope is 12db butterworth. You can try the other settings like 6db but , or 18db but as well. To go lower then 20hz, there is a workaround right here

The hpf and all inuke settings can be done on the front panel or by using the software that came with the amp.

6) I'm dying let me turn it on ???

Yes you can now turn it on after you set the gains on the inuke to 3pm on a clockface (can be fine tuned later). Start up the system and ....... Did it work ???? If not skip down to question 9 for help

7) How do I fine tune my sub for best sound ?

It starts with subwoofer placement. If you can place the sub in several locations (not always an option) then doing the subwoofer crawl is best. You need a spl meter or measurement mic to do this. Spl meter can be bought at radio shack or on ebay for 25-50$.

With only one sub you are likely to have a serious null(bass goes down a lot in a frequency range) or peak(bass goes up a lot in a frequncy range)

This is why 2 to 4 subs help smooth room modes(peaks and nulls) They give you additional bass but equally important is they give you even bass throughout the range from 18hz to 90hz. Its not pleasant to watch a movie and have a 50hz peak booming frequently .

To really see what's going on with your subs you need to take measurements. I created a very basic guide for this.

Here is another guide as well that's more detailed

You can take measurements with your spl or a more detailed way us with a calibrated mic. Minidsp offers this one
And cross spectrum as well

8) What are the flashing lights on the inuke amp for ?

Their are four lights for each channel. First three are orange (power lights) and top one is red (clipping light). During heavy bass scenes its common for three power lights to flash or stay on. The red clipping light should only flash maybe a couple times a movie for a brief time. If the clipping light is coming on for two seconds straight the amp is in serious distortion. Here is a simple guide to setting the amps gains to avoid clipping your amp.

1,234 Posts
Great idea. I had a lot of cross post reading to keep my questions fairly minimal.
This is great to keep it in a single spot and maybe link it to the DIY FAQ sticky. Along with setting the inuke gains and proper speakon wiring for bridged vs stereo, setting the xover in Inuke to go below 20hz, and some settings within there etc which seemed to be very common questions with all the new DIY builds.
I found alot of the stuff I needed by accident that I would not have known otherwise I would have needed.

1,234 Posts
Nice post Donny. 2014 MVP material, all the way: )
Agreed! Donny has helped me quite a bit between PM's and cross posts in other threads. Much appreciated!

342 Posts
I built a mini and will be finishing a cube in the next day or 2. My understanding was the mini can go lower and the cube has a little more output from 30hz to 100hz. So to get the best of both, I built both.
I have a little more leeway with my room layout then others so of course that helped. And for WAF, I went the "ask for forgiveness" route instead of the "permission" route. Lol

Sent from my HTCONE using Tapatalk 4

6,337 Posts
Discussion Starter · #18 ·
I built a mini and will be finishing a cube in the next day or 2. My understanding was the mini can go lower and the cube has a little more output from 30hz to 100hz. So to get the best of both, I built both.
I have a little more leeway with my room layout then others so of course that helped. And for WAF, I went the "ask for forgiveness" route instead of the "permission" route. Lol

Sent from my HTCONE using Tapatalk 4
Cube a bit better from 50 to 100. Its a killer combo. Show some pics when done.

2,166 Posts
Awesome stuff, Donny. I'd love to see the SPL graphs have the SI18, UXL, and Ultimax for all three box sizes. In fact, "which driver" and "which box" are equally important yet somewhat separate decisions to make. A "which amp for which driver" blurb would help as well. And linking back to things like the related tutorial threads, like how to set the below-20 LPF, your REW tutorial. And I remember something about recommended Speakon connectors that are airtight.

6,337 Posts
Discussion Starter · #20 ·
Awesome stuff, Donny. I'd love to see the SPL graphs have the SI18, UXL, and Ultimax for all three box sizes. In fact, "which driver" and "which box" are equally important yet somewhat separate decisions to make. A "which amp for which driver" blurb would help as well. And linking back to things like the related tutorial threads, like how to set the below-20 LPF, your REW tutorial. And I remember something about recommended Speakon connectors that are airtight.
Anyone who wants to create a marty graph is welcome. I have never figured out how to use winisd . If someone does a good graph I will post it at top. Will have lots of links. Going to be one mother of FAQ . Glad i reserved first three posts.

Can I get some people to repost there awesome martypics here. Then I can easily put them in post 3. Once there are a couple of hundred posts its nice to have a bunch in one post. I don't want to have to go through a bunch of build threads.

Need some from kevings , martycool , mhutchins , and anyone else. Even you jbrown even though its not a marty

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