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Slot Ported Nearfield MBM w/ PA460

20K views 100 replies 22 participants last post by  ya9ae 
#1 · (Edited)
Not necessarily sure what I was thinking, but a week or so ago, I came across some PartsExpress.com coupons. Though I'm not generally an impulse buyer, I decided to pull the trigger on two Dayton PA-460s. I'd been eyeing these for use as a nearfield sub. I was initially looking at getting the Behringer B1200D-PRO for placement behind my seats.

I've been following the Nearfield Ported MBM for Increased Mid-Bass Tactile Response Thread, which has some great info on the tactile response from using nearfield ported subs as an MBM. The B1200D is going for around $300. However, I figured that for that price, I could DIY something instead.

Since I don't have the space for the VBSS, I reached out to @mtg90, to see if I could do a shallower version of the VBSS. He suggested that I do a shallower slot ported enclosure, which isn't really the VBSS design (and which wouldn't need EQ adjustments, just a HPF). Nevertheless, I decided to give it a shot. With the help of @mtg90 and @LTD02, below are the dimensions I was planning on using for making two separate enclosures.



Here is a rudimentary mockup from @LTD02:



Since I had leftover wood from my two Modified Cyclops/Skinny Marty build, I had to modify the above dimensions slighly by adding .5" to the height and subtracting .5" from the width. I don't believe there will be an appreciable difference with the slight modification. The dimensions for the modified version are below:



I started building these bad boys over the weekend and hope to have them finished shortly. I'll have a tall order getting these integrated with the rest of the subs in my room, but for the price I couldn't resist.




I plan on powering these two subs with an iNuke 1000DSP wired in parallel.

 
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#3 ·
You have been busy like Brian's saying. I like the box size having the depth at 14.5" inches it makes the placement of these easier to manage in your room. Having these nearfield while Gun shots are going off from movies and explosions are going to sound and feel great in your chairs. It really brings the movie to life.
 
#10 ·
@VicTorious1
Cool! Nice looking project.
I've been reading all the recent MBM, VBSS & PA460 threads. I have something in mind but it will be a little different from a standard VBSS, so I was curious about yours since it's a little different too. Mainly I'm curious about the tune frequencies people are using and what effect it has on output/feel/FR/TR.
I get the impression people are using lower tune frequencies than the PA460 prefers, and if you're at 40Hz, at seems higher than a lot of the other builds I've seen, so i imagine you should be closer to the 460's efficiency range :).
Just looking for some seat-of-the-pants, real world feedback, and thinking ahead about my own goals.
 
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#12 ·
Yeah, I was looking for getting that tactile feel, and more importantly, that chest slam. I was initially going to tune it around 50hz but after playing around with some models and taking to LTD02 and mtg90, I decided to shoot for a little lower tune. Based on the MBM thread, it appears that there is increased tactile energy around port tune. What are your plans for this driver?
 
#17 ·
Nice work @VicTorious1

Your build is looking great! Looking forward to your impressions!

I'm guessing it will probably make sense to place this "upside down" so that the ports are on top, closer to your chest.

Also, for those thinking about optimizing TR, it would be interesting to design something with a slot port that extends vertically; essentially distributing the TR by the height of the sub instead of the width. Pro and cons depending on what frequencies you want to optimize TR, but would be interesting.

-Dom
 
#19 ·
Any thoughts on how I should finish these MBMs? Since they will be nearfield and not behind the AT screen, I was thinking of going with paint or vinyl instead of Duratex. I have some Duratex left over from my Stonehenges, but it might run out after I finish painting the Cyclops subs. @eng-399 - what paint did you use on your HTM-10s?
 
#23 ·
Thanks, Brian. I might have to take you up on that. I'll see how much I have left when I paint each Cyclops.

I used this from Home Depot the finish is really nice and easy to wipe off if you have kids.
I used this primer to.
Thanks. I think I'm going to go this route. I'm not sure I want to try vinyl laminate unless I have the time. Paint seems much easier.

why the pa460 over the 460ho or um-18?
The PA460 is just going into the small cabs which will be used as nearfield MBMs. The 460ho or UM18, don't model well in this small of a cab. The bigger cabs in the back were designed for the UM18, but I'm using the SI DS4 18 for those, not the PA460.
 
#24 ·
I was able to sand these (probably could've sanded them even more, but I didn't have much time) over the weekend. I also put on a coat of primer. @eng-399 - I presume you just use one coat of the latex primer and then one or two coats of the Behr Marquee? I picked that paint up this weekend as well.

 
#25 ·
I was able to sand these (probably could've sanded them even more, but I didn't have much time) over the weekend. I also put on a coat of primer. @eng-399 - I presume you just use one coat of the latex primer and then one or two coats of the Behr Marquee? I picked that paint up this weekend as well.





Pretty much like your saying above I give them one good coat of primer let it dry and look all over the box to make sure it has a good coat on it and if theres any spots that aren't covered completely I give it one more coat. Normally one thick coat covers it with the tinted paint since I normally paint everything black. Then the final 2 coats of Behr Marquee. The paint isn't cheap but either are the kits your building so what's a few more dollars for something that your going to enjoy and show your friends. I can't wait to see how your boxes look once painted!
If you want to go a little crazy with it there's always one side that doesn't get painted which would be the bottom. You can run frog tape on all the edges on it so there isn't any paint build up/ thick paint on the bottom. Doing that will make a perfect finish.
 
#26 ·
This is brilliant! I bought 4 of these PA460 last year and a couple of Yung 300W plate amps, because I've always loved the way pro sound subs sound/feel. I never got around to building them because I knew they wouldn't have enough extension to make great subs. But to use them as mid-bass modules in conjunction with real subwoofers might just give me the best of both worlds. I'm excited now!


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#56 ·
those drivers in a cab that is tuned toward the lower side of things may surprise. in a 22hz tuned cab, output in 2pi space is north of 123db at 20hz. for most folks that would be "sufficient". :) most cabs that such drivers come in are not designed to be used low, having tunings from anywhere from about 40-50hz or so, which maximizes music output, but misses too much of the action for movies.
 
#27 ·
So, I finished these MBMs (but still need to paint the ports). I'm having some issues with hooking these up to the inuke 1000DSP. First I hooked a 12AWG wire up to the inuke using an NL4 Speakon connector (positive wire to the +1 and negative wire to the +2). I'm running the amp in bridged mode. I next used a 12AWG wire to connect the positive binding post/terminal on the first sub to the positive binding post/terminal on the second sub. I then did the same with the negative connection.

I've played with the inuke settings and initially set the max voltage to 50 volts and then bumped them up to 60 votes. When I play a clip, I'm barely getting any sound through the MBMs. Even when I turn the gain almost all the way up, the inuke isn't sending much to the MBMs. The signal gauge on the inuke settings is barely showing any input unless I turn the gain dial almost all the way up.

I tried using two separate 12AWG speaker wires and connected the red wires to the +1 and the black wires to the +2. Still not much luck. Any suggestions? Thanks.
 
#30 ·
While I'm still trying to work through connecting/setting up these up, here are some near final pics. Still have to paint the ports. I'll be picking up a long brush tomorrow. I probably should've wiped these down prior to taking pics. Thanks to @eng-399 - for the paint suggestion.




 
#32 ·
Looks like everything is correct, so it's not likely a problem with the amp. Possibly the wiring to the sub or a setting in the AVR.

How do the input and output levels look in the DSP? Do the input and output both go up at least half way? Do they both go up the same amount?

You could check the speakon unhooked from the amp to see how many ohms you've got.
 
#34 ·
The input and output levels are barely making a blip. They show nothing unless I have the physical gain dial turned almost all the way up. They are definitely not going up even halfway. I believe the input and output levels are going up the same amount as each other, however small that amount is. Do I have the correct voltage? If the inuke can do 750w RMS bridged info a 4 ohm load, should I increase the voltage to 73 or so?

Start by turning the front panel amp knobs fully clockwise, otherwise your AVR signal is being attenuated.
I'll try turning them fully clockwise. When I did this before, the input/output levels still didn't go up over halfway.

What's the best way to wire two speakers in parallel to a bridged amp? Is the first way I described previously okay? Which is to say, is it okay to wire one sub to the amp using a Speakon and then daisy-chaining the other sub by connecting it to the terminals of the first sub? This is how i first connected it. Afterwards, I tried fitting two sets of 12awg speaker wire by squeezing them into the Speakon head and tightening the little screw as much as I could. Clearly, the head of the Speakon connector is not meant to take that sized wire.

You guys' help is appreciated. Thanks.
 
#33 ·
Start by turning the front panel amp knobs fully clockwise, otherwise your AVR signal is being attenuated.
 
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#35 ·
Daisy chaining the subs is correct. Less wire is better. Just make sure you have a parallel connection and not a series connection. Your ohm load should be around 5 or 6, not 17 or 18. You can check that at your speakon with a multimeter.

Since your input levels are low you might have a setting in the AVR wrong. Speakers should be small and crossover in the 80hz range. You can try the sub level at 0 to test things out. If those don't work it gets tough to troubleshoot from there via the internet.
 
#36 ·
When I played around with it this morning the level lights were showing up higher. I decided to rewire it daisy chained and they're running right. Not sure what the issue was. Last night the fan on the inuke 1000 was running super hard compared to my two inuke 6000s. I pusher my chair up against the MBMs and the tactile feel is real nice. Thanks @Samps and @FriscoDTM. I suspect the gain dials weren't completely turned all the way up.
 
#41 ·
Great looking build Vic, now you've got me contemplating grabbing a few of those PA460's for a nearfield mbm setup myself.

I'm curious though, what adapter are you referring to? I've got a nasty hum coming from my Inuke 3k that's feeding the 4 CS1214 subs and it goes away (attenuates) if I turn the amp gain down. Will your adapter help with this?


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#40 ·
sweet looking set up man....congrats.
 
#43 · (Edited)
So, I was able to tinker with these a little bit this morning as I haven't been too happy with the output from these MBMs. I had the external gain dial on the iNuke turned all the way up and all of my other six subs turned off. The MBMs didn't seem to have much output. I went ahead and unplugged my mains, raised the HPF from 35hz to 40hz, added +4db gain in the Filter/Crossover tab of iNuke and turned up the volume on the AVR. Man, do these things thump. It looks like I need to re-run Audyssey. I have a minidsp coming today for my two SVS subs and I hope to run REW and re-run Audyssey this weekend. These MBMs get quite loud and the tactile response coming from the port is quite nice. Can't wait to get it all dialed in.
 
#46 ·
Audyssey may be part of your problem. Its cutting frequencies to your MBM's just like the other subs but since they are nearfield, the effect can be negative especially if its cutting frequencies where you want the MBM's operating. After running Audssey, try getting a closed mic reading from your MBM's. You may have to tweak the iNuke DSP to get them back to normal.
 
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