Dual Opposed Mach 5 Audio FTW Build

[fuzz092888]

Powerful amps for a lot less cash, no doubt. But the SP's will get you more actual power (~2dB) if you can't get some additional lines.

Very true, but I'd rather go with the Sanway or A14K, even if it doesn't net me much or anything in the short term since the plan isn't to stay in here more than another year or two max.

If I can get a job back home and if I can talk the GF into it my parents will give us a few acres and we'd be able to build. 220v and 20amp lines galore Especially since I can get my cousin to do all the electrical work on the cheap. Lots of ifs though with an unclear timeline.

 

[Steve81]

I'm going to set a reminder for 5 years down the line to go back to this thread and say "told you so" when you still haven't moved

New question: how much Vb do your LMS's and UXL's currently get?

 

[fuzz092888]

LMS are currently in 4cuft flat packs from diysoundgroup and UXL's are sharing about 4 cubes after bracing and whatnot.

 

[Steve81]

Well the FTWs should make a useful impact by virtue of their added efficiency in a box the size of a washing machine Truth be told, I'm not sure how useful the 18's will be given your wall limitations once the FTWs come online outside of being relegated to helper subs.

 

[fuzz092888]

Well the FTWs should make a useful impact by virtue of their added efficiency in a box the size of a washing machine Truth be told, I'm not sure how useful the 18's will be given your wall limitations once the FTWs come online outside of being relegated to helper subs.

Well, odds are the UXL's are done for when the new sub gets built, either until they get sold or until I move.......which will DEFINITELY be sooner than 5 years

Also, I may run with a new plan. I was fartin' around and had a thought as I was pursuing diysoundgroup. There's a dual opposed 8cuft flat pack on there that would just about fit the FTW drivers for about $160 to my door.

Doesn't look too bad, total Vb is about 7.2 cubes. Roll off starts around 76Hz, F3 is 50.68Hz before boost is applied. With 1000 watts, before the roll off it's modeling at 126db, and at 10Hz it's at 99db.

 

[Steve81]

It's not great considering the numbers are for 1m. A single LMS-U put out 93dB at 10Hz in Josh's long term sweep test with a 73V input, and that's at 2m with 73V representing just a tad over a kW to the load. A pair of FTWs will still have more in the tank, but that box size is going to drive down the low end efficiency.

 

[fuzz092888]

It's not great considering the numbers are for 1m. A single LMS-U put out 93dB at 10Hz in Josh's long term sweep test with a 73V input, and that's at 2m with 73V representing not a lot more than a kW to the load. The FTWs will still have more in the tank, but it looks like that box size is radically reducing low end efficiency.

I dont' know that I agree. According to the models the difference between 7.2cuft vs 15cuft at 10Hz is 4.3db. While that represents a doubling of power and a bit more, weighing that against the size, cost of build and time to build the larger box vs ordering the flat pack isn't insignificant. Plus the F3 of the larger box is 3db higher at 53Hz. While the larger box can certainly deliver a bit more down low and make the roll off a bit shallower, I'm not sure a 3db difference at 20hz and a 4.3db difference at 10hz is radical enough to offset the other factors involved.

Thoughts?

 

[Steve81]

I'm not sure a 3db difference at 20hz and a 4.3db difference at 10hz is radical enough to offset the other factors involved

Think of it this way: given your current circumstances, how big of an upgrade will the FTWs loaded into the 8cf flat pack represent over the UXL DO box it will replace? I'm guessing you aren't making the UXLs beg for mercy, so the main benefit beyond bragging rights is an incremental gain in efficiency. Doesn't exactly seem worth the effort, but that's just MHO. The big box, while a giant PITA, would turn that marginal gain into a reasonably large step up. Still, I'd agree that I'm not sure it's really worth the effort/massive box in my living room.

Given the practical issues that you're facing (space, power, etc.), I'd think hard about simplifying your setup. Putting each FTW into a ~7cf cabinet, and selling or storing the LMS-U's and UXLs until you move seems like the most viable option. You won't sacrifice any output over your current setup and it wouldn't necessarily take up a lot more room. More to the point, with a single 15A/120V line, it's not like you're going to do justice to a pair of FTWs and a pair of LMS-U's anyway.

 

[fuzz092888]

Think of it this way: given your current circumstances, how big of an upgrade will the FTWs loaded into the 8cf flat pack represent over the UXL DO box it will replace? I'm guessing you aren't making the UXLs beg for mercy, so the main benefit beyond bragging rights is an incremental gain in efficiency. Doesn't exactly seem worth the effort, but that's just MHO. The big box, while a giant PITA, would turn that marginal gain into a reasonably large step up. Still, I'd agree that I'm not sure it's really worth the effort/massive box in my living room.

Given the practical issues that you're facing (space, power, etc.), I'd think hard about simplifying your setup. Putting each FTW into a ~7cf cabinet, and selling or storing the LMS-U's and UXLs until you move seems like the most viable option. You won't sacrifice any output over your current setup and it wouldn't necessarily take up a lot more room. More to the point, with a single 15A/120V line, it's not like you're going to do justice to a pair of FTWs and a pair of LMS-U's anyway.

While valid points, I think going back quite a few posts now, you've missed the whole point of this project








Which is to build a new sub. Same reason why the guys over at PETT build more speakers when they already have or have built 30 pairs. Plus, if I save money and time and go with the flat pack I can have the guy at school teach me how to put a professional automotive finish on it. Then when I move I can scrap that cabinet and put them in 12-15 cuft boxes per sub or even go IB if the situation is right for it.

I just want to build stuff. I'm not a set it and forget it type of guy. If I'm not building or rebuilding, then I'm planning a build or a rebuild. Where's the fun in letting this stuff just sit around doing it's thing?

Also, I got the adapters in so I'll be able to have a real test sometime to see what I'm getting from the subs/wall. Should be interesting.

 

[Steve81]

you've missed the whole point of this project

Which is to build a new sub.

I get that, and I'm not saying to nix the whole project or anything. I'm just thinking out loud as to what would net you the best results given that you've invested a fair sum in the FTWs.

Now if you're not married to the idea of a DO, but would still like a flat pack, there is one other potential option... Technically, DIYSG's sealed box offerings top out at 4cf, but their ported offerings go up to 5.4cf (plus volume for the slot port). All you'd really need to make that a go is a blank baffle, which I assume shouldn't be a huge problem for Erich. You'd net 50% more Vb for each driver vs the DO box, and corresponding benefits in efficiency and reduced distortion. Box size isn't outrageous, and if you opt to keep the LMS-U's in the game, you could do two stacks of one FTW and one LMS. Win (flat pack) - win (efficiency) - win (low footprint) - win (busywork for YAA). Drugged up Charlie Sheen would be proud.

 

[fuzz092888]

Now if you're not married to the idea of a DO, but would still like a flat pack, there is one other potential option... Technically, DIYSG's sealed box offerings top out at 4cf, but their ported offerings go up to 5.4cf (plus volume for the slot port). All you'd really need to make that a go is a blank baffle, which I assume shouldn't be a huge problem for Erich. You'd net 50% more Vb for each driver vs the DO box, and corresponding benefits in efficiency and reduced distortion. Box size isn't outrageous, and if you opt to keep the LMS-U's in the game, you could do two stacks of one FTW and one LMS. Win (flat pack) - win (efficiency) - win (low footprint) - win (busywork for YAA). Drugged up Charlie Sheen would be proud.

With the extra work and cost involved I'd be better off just sticking with the original plan and building the big DO. Two of those, minus the substructure would cost $200, plus a 2-4 MDF handy panels from HD for bracing and new baffles and I'd be $50+ over the cost of the 4 sheets of Ply and at least $100 4 sheets of MDF.

I'm more cheap than lazy so that ain't gonna fly

In any case, I've got at least one project to keep me busy through the weekend and that's installing the receiver hitch I just got. $88 vs what the dealer wanted to install one $600+. Now I just need one of those 1up bike racks PDdawg has mentioned.

 

[Steve81]

With the extra work and cost involved I'd be better off just sticking with the original plan and building the big DO. Two of those, minus the substructure would cost $200, plus a 2-4 MDF handy panels from HD for bracing and new baffles and I'd be $50+ over the cost of the 4 sheets of Ply and at least $100 4 sheets of MDF.

I'm more cheap than lazy so that ain't gonna fly

Not necessarily. You don't need new baffles, just have DIYSG send you blanks in lieu of ones with cutouts for an 18" driver and a port. As I see it, you're going to basically be in the same spot with the 8cf DO box, as they don't do cutouts for 21" drivers. If they're nice, they may even be able to cut you a discount as its less work for them. Same thing with the substructure. You don't need the port, just the brace, so you can see if they'll cut a deal there as well. Doesn't hurt to ask. If you can get the revised flat packs for ~300, it'd be worthwhile IMHO. Sell off a UXL, and you've got the cabinet funded.

 

[fuzz092888]

Not necessarily. You don't need new baffles, just have DIYSG send you blanks in lieu of ones with cutouts for an 18" driver and a port. As I see it, you're going to basically be in the same spot with the 8cf DO box, as they don't do cutouts for 21" drivers. If they're nice, they may even be able to cut you a discount as its less work for them. Same thing with the substructure. You don't need the port, just the brace, so you can see if they'll cut a deal there as well. Doesn't hurt to ask. If you can get the revised flat packs for ~300, it'd be worthwhile IMHO. Sell off a UXL, and you've got the cabinet funded.

Already asked awhile back. They stopped doing blanks and custom work awhile ago.

 

[Steve81]

Well they suck in that case

 

[fuzz092888]

Well they suck in that case

Yea, I asked Erich and I guess the place he orders from will only cut in bulk with no variations or he has to specify a certain number of blanks when he orders and since he doesn't get that request enough it ain't gonna happen.

 

[fuzz092888]

Well thanks to Steve's badgering p) I redesigned the box. Now I'm sitting at 14.6-15 cubes not counting bracing and driver volume. As best as I can remember, this is the new box vs what the UXL's have right now. Still fits on 4 sheets.

Also to be noted is the this is with 500W, which should keep me well within what the wall can deliver.

 

[fuzz092888]

3 pages of sh!t and nothing's even been built yet One trip to HD and a grouchy employee later.....

 

[Alex2507]

I looked to the light switch for scale. The panels are 4 foot. Then I looked at the lamp base. That sub is f^%&ing big. I'd be pissed about having to cut all that MDF too. The HD guy was probably wishing that you would embrace DIY more fully.

Really looking forward to that raw MDF look that is all the rage this subwoofer building season. Why do we not seal MDF with the same Minwax Natural Stain that we use on real wood?

 

[fuzz092888]

I looked to the light switch for scale. The panels are 4 foot. Then I looked at the lamp base. That sub is f^%&ing big. I'd be pissed about having to cut all that MDF too. The HD guy was probably wishing that you would embrace DIY more fully.

Really looking forward to that raw MDF look that is all the rage this subwoofer building season. Why do we not seal MDF with the same Minwax Natural Stain that we use on real wood?

Eh, he barely had to do anything. He was just being a cranky pants and it's a good thing I had him cut it oversized because there are some banged up edges from him dropping the sheets onto the rollers. I'd be more than happy to embrace more DIY if I had my table saw and a bigger vehicle, but I just couldn't swing the Tacoma.

Oh, new sub dimensions are 29.5" X 34.5" X 34" external.

 

[Alex2507]

Tacomas look funny with 4x8 sheets. Even my 6.5' F150 bed is sh!t for that.

I suppose it would depend on my mood but in your place I might have found myself making the HD dude keep cutting pieces until he handed me undamaged material ... but that was me with good knees. Bullying is way more fun than bluffing.

Near as I can tell this is the grandest sub build around here ever. I wasn't kidding about running a 30 amp line. Rick will know how. Invite him down when it's done. Now I'm thinking about how I would do that here. Clean electricity is 80, no, 90 percent of the sound.