Sub build using (4) Dayton Audio DVC310-88s

[kevinm]

Hi guys...looking for some advice!

I have (4) Dayton Audio DVC310-88s that are split between in 7 cubic foot enclosures (see below). I was gearing up to start finishing them when I decided it'd probably be almost the same amount of work to just build new enclosures that needed less prep. Additionally, I think I'd like to make them smaller and with better bracing. Better yet, I won't have to go LFE-less while I build, prep, paint and finish

So, I'm looking at 4.5 cubic feet (probably will bump up to 5 to account for bracing and driver displacement) per pair of drivers. They'll be powered by a Dayton Audio SA1000 amp (about 950w to power all 4).

From what I've seen online, there aren't many HT subwoofer designs using dual drivers that are 12s ( at least that I've found, please feel free to direct me if you know of anything). Most are 15s and 18s in front loaded designs. Does anyone have any recommendation on driver orientation that I should look into? Stick with both front loaded? Opposed drivers? Any others?

Mostly looking to keep the box size below 5 cubic feet per pair have a clean look (when finished) - will probably end up with Piano black. What do you guys think?

[5th element]

One driver on the front, one on the back. Reverse mount the one on the back so that it fires into the cabinet with the magnet pointing outwards. Preferably have the drivers mounted close to the floor to keep the thing more stable, keep the centre of gravity lower and to provide as much boundary gain as you can get.

Place the port and the internal bracing such that the end of the port is as clear from any surfaces as possible.

[kevinm]

Thanks for jumping in 5th! Congrats by the way!

So I assume you are referring to this design, but dual opposed.


From what I've read, this reduces linear distortion. Does the reversed mount increase vas? Is it more beneficial than a more traditional dual opposed design such as these? Maybe to answer my own question, but these designs seem to be all sealed - so would that be part of the reason why these won't be optimal for my particular situation?


Lastly, I have seen a few of these....


Any experience or knowledge of this type of design?

[5th element]

Going push-pull (one driver mounted normally and one mounted with the magnet facing outside of the cabinet) creates a nice cancellation of even order non-linear distortion products. (Linear distortion is simply any deviation from 'flat' in the frequency response.)



You can see an example of this in a measurement I made of some Peerless XLS drivers. The upper trace, the kinda yellowy one, is two drivers mounted in the standard push-push fashion. The bottom, greeny-blue trace, is with one driver flipped with the magnet facing out. You can see there is a significant decrease in distortion. This only shows the 2nd order distortion as the others remained pretty much unchanged. Needless to say, for a sub, reducing the distortion at 20Hz from 8%, in this case, down to 2% is rather significant. And you can see it has a noticeable effect up to just above 100Hz - just the range we want to the sub to realistically cover.

Now those cabinets with drivers mounted push-pull, but with one driver concealed within a hidden chamber, or on the adjacent face compared to the front firing driver, still benefit from the push-pull arrangement, but I would imagine that the decision to mount them like that is more due to how it looks. Having the second driver mounted like in the X12 is certainly fairly unobtrusive and most people probably don't appreciate having magnets sticking outwards.

It's a shame though because putting the magnet side driver on the rear would be the icing on the sub-woofer cake. When configured as such, when the driver on the front moves forwards, the one on the back moves backwards and any force that would encourage the enclosure to shake or move is completely cancelled out.

A ported enclosure benefits from these just as much as a sealed one does, it's just that small sealed cabinets are very much en vogue when it comes to domestic acceptance. I am in agreement with this as I like my small multiple subs, but if I had the space I'd sure go with a large vented cabinet, at least for the main sub.

Reverse mounting by the way is just the same as standard mounting in that you need to double the enclosure volume when using two drivers. There's no special to it, unlike an isobaric arrangement which halves the VAS.

[kevinm]

Oh, wow. Thanks very much for the detailed explanation. I'm assuming one of the advantages of this design is that one can easily switch the direction of the woofer if need be? With the WAF in mind, the only I could pull this idea off is to have the traditionally mounted driver facing forward and the reverse mounted woofer facing the front wall so it's hidden. Any problems with this as long as their is sufficient space between the driver and wall?

[5th element]

Nope that'd be fine.

[JonMarsh]

Nice plan shaping up, and great advice! I saw the thread just as going out to dinner last night, but there's no need for me to contribute at this point, other than to remind you to post pictures when you're putting them together! :W

[kevinm]

Thanks, John and 5th.

Alright, so to explore the push push idea 5th mentioned up above, I am seeing that 21in height x 21in width x 25in depth will give me the needed volume. In order to keep the ports away from any walls, that leaves me with front firing or top firing. Front firing can easily be concealed with a speaker grill, so I think that this is the best bet.

As for ports, I am thinking the best option is a an 19.5in width x 2in tall slot is the best option. Minimal velocity and probably the most aesthetically pleasing. OTOH, PVC ports are the easiest to adjust. hmmmm

Below are the options I'm looking at.

[Hdale85]

Can't you mount both baskets internal and reverse the polarity on the rear driver for the same effect? Granted there would be more volume taken up by the extra basket.

[JonMarsh]

Nope. Then the rear driver would be running out of phase acoustically. All kinds of cancelation of main output would occur, not cancellation of differences in even order motor distortion!

[kevinm]

Looks like I'll be getting to make some sawdust this weekend.

I think I mostly finalized the design and have settled on an 20in x 22in x 29 enclosure for net 4.5ft^3 after driver, bracing, and port displacement. The port length should give me a tuning right at about 20hz give or take a hertz. I had a chance to check out Google Sketchup today and learn the basics, so I made a little model. All calculations are for one enclosure with 2 drivers.

Here is modeled SPL



Modeled cone excursion at max power



And here is the sketch up....I didn't add the cutouts to the internal bracing...but there will be plenty of cut outs for air flow

Baffle shot



Side shot



Angle shot



Any red flags? advice?

EDIT - switched images to htguide. They should work now!

[5th element]

Hmm none of your images are working. I tried to edit your post (my first proper mod job!) in the hope of correcting the issue, but it appears that is beyond our capabilities (maybe I missed something). If you could try again? Maybe Jon could chime in.

[kevinm]

I changed the source. They work now

[5th element]

Indeed.

I'm liking the design and the slotted port.

You're going to be getting plenty of output out of those that's for sure!

They remind me of the Wilson WatchDog and are certainly more WAF friendly than what you currently have.

110dB at 20Hz 2pi no doubt, but floor and corner mounted you'll get all that back. I wouldn't be surprised if you can push 120dB+ at 20Hz in room on transients for the pair.

Construction looks fairly simple, I bet you're rather exciting to start making saw dust

[kevinm]

I'm very excited. I've been projectless for about 4 days, so I am more than ready

The GF is going to be very happy with the change...especially since these ones will be painted BEFORE they get installed. I've noticed it is very hard to take everything apart and finish them once you've gotten use to their presence. Who would have thought? :roll:

[5th element]

Haha who would have thought, but the temptation to put everything together is very hard to resist! Especially if you're not sure if you want to keep them, or if this is more of a 'test' scenario etc.

[kevinm]

I'm worried about that.....I'll have to come up with a contingency plan! Most likely the GF will crack the whip. Hehehe

[5th element]

The good news is that you have the old boxes. So you could wire the new ones up, see how they perform. Then swap the drivers out, one box at a time, until you finish them off.

[kevinm]

I doubt ill have the self-control to risk any of that!!

As promised, cut the wood this weekend and received the Fuji spray system yesterday. Now I'm getting excited!!

[JonMarsh]

Piece by piece, you're making progress! At some points it feels like it will be forever before a project gets finished, but a steady measured effort taking your time to do a good job at each step is very satisfying in the end.

[kevinm]

At some points it feels like it will be forever before a project gets finished

Tell me about it! Now we are off to the GF's brother's graduation in New Jersey for a while. If it wasn't for the excellent Filipino food, I might be a little more upset at the delay in construction

[kevinm]

Small update - managed to get the baffles glued together, braces routed, rounded and clamped. Before I routed and rounded, I would never have believed how labor intensive that is. Wow!





This weekend I am hoping to get the boxes glued up. Then it'll be time to start covering in hardboard and prepping for finish. I am excited to try out my Fuji spray system!

[5th element]

Yeah getting all the panels measured and cut and measuring several times as you go does take time. Then there's cutting all the holes and using the round over bit on them. You're making nice progress though. It's going to be interesting seeing the final product and especially hearing what you think of them They should be noticeably cleaner ime.

[kevinm]

I'm really excited. Final product should be 4.15 net cubic ft tuned to about 20hz. Excursion levels are safe in my target range, so these should sound really tight.

Made more progress today - got the ports glued and the bracing on top of that. The port gluing was actually quite the brain teaser - took a little experimentation to get a viable option. Ended up gluing the port brace (2in tall, 3/4in wide) first, then placing 2in "supports" (spare wood) on either side to support the port board. Worked rather well.





Did hit a snag with the bracing though - all in all, it ended up being about 1/8in - 1/4in taller than the side of the outer box. So, I need to shave about 1/8in off the top of brace...i'm thinking sanding is my best bet. Any thoughts? I could also add 1/8in to the top of the side board. Whatchu guys think?

[5th element]

Loadsa clamps, yes!

It's difficult to know what to recommend. Personally I'd try and clamp a straight edge in and remove the excess with a router, but if that's not possible, both sanding and gluing will work. If you've got material of a suitable thickness, ie like adding in a few of layers of veneer, then that would work well. Sanding can be very hard work and 1/8" is quite a lot to sand away.

[knowledgebass]

Could you cut a dado on the capping piece? For me, I'd probably use a hand plane if it had to be trimmed.

[kevinm]

I thought about doing that too. Ended up with 5th recommendation on using a router. Worked pretty well. I just added scrap on each side of the piece that needed to be reduced to use as a guide. Just did a little sanding after that and was good to go. I have the first one gluing up now - sans the baffles!

[5th element]

You've really done a good job with those. I like the plywood look too.

[kevinm]

Thanks 5th. I am liking them too. These guys along with the rest of the theater stuff are going to be painted black, but these plus the ardents builds are making me want to play with some veneer and a natural wood finish.


I actually have pieces of Owk Ply cut to make a equipment/media console for under the tv that I want to finish in a really nice ebony stain. That'll be my first venture. After that, I need figure a use for the RS180-8s I have.

[knowledgebass]

Looking great! My media console became a toy box for my kid (soon to be plural) and I was hoping to "upgrade" it with a sub sort of like this.

[dar47]

Very nice Kev. :T

If it wasn't sitting on the end of that sheet on your horses I would think it was as big as a bus, haha. Your bracing work out well and going to make some big sound.

[kevinm]

Thanks guys!

Knowledgebass, you're looking to make a sub that looks like a media console? Have you browsed the finished sub thread? Some very cool furniture themed subs!

Dar, I was actually think how small they seemed heheheh. Compared to the current cabinets, they seem very small.

I am planning the painting stage, anyone have any idea how I could hang them while I paint them? I could put a 2x4 across the driver opening and attach a string to it, but I need something to hang that off of. Anyone have any ideas?

[kevinm]

Quick update....

Finished routing the driver recesses and cut outs with 1/2in chamfer on inside



Gluing the first box together



Both glued together and flush trimmed.



Now onto cutting out the port opening cover the remaining 4 sides in hardboard.

[JonMarsh]

A lot of solid progress here, Kevin! :T You're getting pretty close- that's a good feeling. :W

[5th element]

A lot of solid progress here, Kevin! :T You're getting pretty close- that's a good feeling. :W

8)

I only wanted to leave the smiley as my reply, to which the forum informed me that the post was too short! :B

[kevinm]

Small, non-glamorous and furry update

Well I had to delay because of a new furry member of the family. The GF and I picked this little girl up about a week and a half ago and have had our hands VERY full.



I have been able to make some progress though. Ports have been opened and routed, 1/8in hardboard slapped on all the sides, edges rounded over, seams bondo'd, and re-sanded. Last night I was able to finish the sanding sealer. Next step is setting up the spray station and starting the primer coats. Hoping to get started on those within the next day or so.

[5th element]

Aww that puppy is adorable I wouldn't say you haven't done much, what you've done is a pretty thankless task and can take a lot longer than you'd anticipate. It isn't unusual for people to procrastinate significantly when they get to this point.

[PassingInterest]

Cute little pooch! Congrats.
The cabs are looking very nice. Fine job.

[kevinm]

Thanks, guys! She sure is adorable! Especially when she is sleeping....when she is awake, it's quite the raucous. I feel like it's what it would be like having Stitch from Lilo and Stitch as a pet would be like.

And you're not joking, that stage took longer than the rest so far!

[5th element]

What breed is she?

[kevinm]

German shepherd!

[kevinm]

Update!

I managed to get my "paint booth" setup. Seriously half-baked looking when compared to the one I found on Pinterest, but it works! Even has positive pressure inside. The cabinets are hanging from the rafters through the access panel to the attic in the garage (benefit of having an engineer for a father when you need ideas!). I just ran a 4x4 across the opening, then two ratchet straps to another board that I could use to space out the cabinets. Then hung two more ratchet straps off that board (one on each end) and to a 2x4 stuck in the driver hole. Overall, I think it works pretty out pretty good as none of the surfaces are touching anything and I can spin them if I need to.




Shot my first coat of primer using my Fuji spray system. Took quite a while to learn the whole acetone/enamel ratio for the gun and then another 45 minutes or so to dial in the gun. After about 1.5 hours of tinkering, I think I got it to work pretty well. The cabinet picture below has a really even coat on it - even though the color is really strange.



Tomorrow will be another coat of primer or 2 and then starting some wet sanding!

[5th element]

That looks fantastic

[ligonk]

+1 for keeping it "WAF-Orange".

[kevinm]

I showed her my progress and the look of horror on her face before she learned that was just the primer coat was priceless. I think a nice polished orange would look pretty good