Best Shallow Sub

It would definitely help! Going back to this pic:


With the sub rear firing, you can just make out where I've got it pushed back all the way and it's touching the seat frame part I was measuring to in the last post. Lifting the seats an inch or so and it might just clear that bar, in which case you could maybe do a slight tilt on the sub like I was thinking to make the magnet and box clear the seat. I've got some scrap wood laying around, I'll test the theory on the passenger side even though the jack stuff is there and report back lol.

 

If you were in southeast Tn. I would gladly bring mine by as I have already relocated my jack and brackets. I'm liking where this is going!

 

I threw a piece of 3/4” board under it and used a strap to hold the seat flat, lined up the holes and it gave a little bit of extra clearance but still not enough to clear the frame:



realized after i was done the picture i took from underneath with the sub rear firing i had my finger over the lens, doh!
I think to truly make a difference you’d need to get the seat forward, although I still think it’s damn close to fitting even without a seat lift or moving the seats forward, think rear firing would be the way to go still and in the pic above you can see there’s a decent 1.5” gap and then if the sub’s surround is truly a half inch shorter than my mockup, that would make for 2” of clearance. 1/2” fiberglass for the back of the box, 1/2” gap between sub and box, 5” mounting depth + 1” of surround height would total 7”, by my measurements the total depth of that space appears to be 8” (5” deep mock up, 1.5” surround height, 1.5” wiggle room). Would literally be playing a game of inches and I’m still tempted to try and probably fail. If anyone knows where I can get an Encore to test fit or a burned up one I’d do my damndest haha

 

I bit the bullet today and decided to go with the Wavtech thinPRO 12 2-ohm version. Modeling it in Winisd and it had has very similar output to a JL 13Tw5, but much more power handling potential before reaching xmax, a lower F3 than the JL and Encore 4412, and similar Qtc to my current sub.

SPL graph for anyone curious:


Green is the Encore 4412, black is the thinPRO, blue is the 13TW5, and pink is my current 8w7.
Box volume: Encore 1.25cf, thinPRO 1.0 cf, TW5 1.0 cf, 8w7 .875 cf
Qtc: Encore .734, thinPRO .801, TW5 .839, 8w7 .809
Input power: Encore 1000w, thinpro12 750w, TW5 600w, 8w7 500w

and then excursion on given specs above:



Max sealed box size Wavtech recommends is 1.0 cf. Increasing the box size to 1.5 drops the Qtc to .724 and increases SPL to match the Encore from 20-40 Hz, 1.25 cf nets a .756 Qtc and SPL matches the Encore between 20-30 Hz



I'll probably play around with it to find the sweet spot of box size, and then a mix of sound deadener inside the box as well as polyfill to lower the Qtc some more, but that then lowers output. Excited to get it in hand and I'll be sure to update box specs and probably start a new audio-build thread to capture everything I've done/continue to do in one place.

 

I've kinda looked at the winisd stuff but I don't have the knowledge and havnt took the time to sit down and play with it. I hate to ask someone to do my homework for me but if you get bored or need a break from your stuff and want to look at something different is there any way you could compare any of those to the 2ohm ddaudio sl612's. Also I'm excited to hear what you think of the wavetech!

 

Yeah give me a little bit and I can post a comparison, Winisd is intimidating, at least to me, and I might not be doing everything correctly but I figure if I’m doing everything equally as wrong it’s still a decent comparison lol, it’s really just putting in the specs in a certain order to not break anything as winisd is kinda finicky, and then it’s just playing around with the box size, power, and adding the low/high pass filters. It’s not perfect though cause it models in an anechoic chamber, fancy way of saying a room with no echoes/reverb, so it doesn’t account for cabin gain, but again, still good to get a general idea of box sizes, excursion, spl etc.

 

I do appreciate it, I'm in no hurry just curious how they compare on paper. I have 2 in a sealed box and love them. The box is sealed with about 2 cubes of space I think. It's like building a big block and think this is a beast but until you compare dyno sheets you never know if it's really awesome or if it's really just the norm. Bad analogy I know, but anyway thanks.

 

So I'll preface this by saying, and this is by no means a dig at DD in particular but rather the car audio market overall, manufacturers often lie, omit, or fudge specs. That goes for subs, amps, speakers, you name it. The DD is missing a few specs but then again JL leaves out specs too so again, not a unique thing to DD. As another example, Wavtech advertises the thinPRO 12 as having 20mm of xmax which seems pretty suspect. Only real way to verify manufacturer claims for subs is to have them independently tested, beyond that we just have to take their word. In modeling, the SL612 looks like a great shallow sub and punches way above its weight as far as modeling goes. Again, I'm no winisd expert so I could have done something wrong for this one (or any of them for that matter), but for SPL:


It's right there alongside the JL 13TW5 (DD is dark blue, JL is light blue). In 1.0 cf on 600w, it nets a .754 Qtc which is fantastic, and for excursion it peaks at about 12/14mm (14mm advertised xmax which is 3mm more than the 13TW5 and 1mm less than the 12TW3 for reference).


I added in the JL12TW3 for comparison, red line on the bottom. The JL12TW3 has 200w less power handling, and you can see it has less xmax, and SPL than everything else. The F3 point of the DD612 is ~40hz, which is about the same as the thinPRO 12.

With all that taken into account, and considering the price point, I think it's a great bang for your buck. I've not modeled one, but in specs/price the DD looks very similar to the Sundown SML12's. All things considered, I think you'd be hard pressed to find a shallow sub with similar SPL at that price point and only real competition would probably be the Sundown. Also I think one of the biggest/most overlooked things in car audio is that it's all subjective, what sounds good to you, I, or anyone else is 100% subjective and as long as it sounds good to you, the person spending your hard earned money on it, that's all that matters. I think a lot of times people get hung up on price, sound quality etc. when in reality 99% of people couldn't care less and they're listening to music to enjoy the music, not the speakers if that makes sense. Anyways, I'll get off my soapbox now haha.

 

I agree, Some people like pineapple on their pizza others look at you like your crazy. Thanks for taking the time do do this for me! One more question, I'm not sure how to read this, which color was the dd?

 

Sorry missed this, the DD is the darker/thicker blue line on all the graphs. In trying to squeeze out as much resolution as possible I cut off the color part, but in Winisd whichever "Project" you have selected under the Projects section, in other words the one highlighted in blue, will be the thickest/bold line on your graphs. When you select on another project it will make that one bold instead and so on.

 

Ok, thank you for clearing that up for me

 

My Wavtech should be here tomorrow, been modeling some box dimensions in a program called Speaker Box Lite. The sub has a 3" mounting depth and with grille a front height of 2-1/8", making for a total height of 5-1/8". I know I could always build a simple wedge box, but 1) to make the sub fit easier/have more clearance and 2) because it looks cooler (even though it'll be behind the seats) I was thinking about building something like this, where the sub sits recessed from the front face.


Obviously not to scale, but you get the idea. Another reason for doing it like this would be so that I could experiment with having the sub front or rear firing since with the sub recessed I wouldn't have to worry about it clearance. Since this design would end up being really wide to get the required air space and I'm trying to keep it to ~35" or less wide, after testing front vs rear firing I'd probably rework the left/right/back and top panels to include a wedge portion, something like this:



Curious if anyone has ever built a similar box and/or experimented with front vs rear firing subs in our trucks? I know the JL stealthbox has the subs rear firing which is what got me thinking about it.

 

Thanks for modeling the DD 612. I’ve got one in my ‘18 CM on 800W and it definitely gets with the program. ~1.75 cf ported enclosure. Can’t remember the exact tuning on it, but it’s right around 30hz. For the price point, I think you’d be hard pressed to do much better with a shallow sub.

 

Definitely a different design from what I've seen, I wonder if the top would be wide enough to mount you amp on a rack on top and have the total package in 1 place

 

Not on the very top as that’ll only be a couple inches wide, but on the sloped face it could definitely be a possibility. I made an amp rack out of hdpe that bolts to the rear window panel with bolts/rivnuts, and my middle-ish mounting points are at ~35” from the passenger side so I’m trying to keep my box narrower than that because the amp rack sticks out an inch or so. This pic is from wiring everything last summer.

General plan is to 1) cut off that part of the amp rack and 2) rearrange the amp rack/eventually replace my RD900/5 amp with a multi channel dsp amp, at which point I’ll remove the crossovers and go fully active, and then replace the sub channel of the RD900/5 with a mono amp, but that’ll be a little while yet. For now just trying to squeeze in the Wavtech will be enough of a challenge given its total height but luckily it doesn’t need any clearance from the back of the enclosure and I’ll need every last 1/10” to squeeze it back there.

 

After taking a lot of measurements, and mounting the Wavetech with grille to a piece of scrap 3/4” plywood, I was able to figure out the angles/depths etc. for everything to work together. Given my box needs to be ~34” or so wide at most and I’m shooting for around 1cf of airspace or slightly higher to get a Qtc of ~.707, I came up with 34” W x 18” H x 7” D1 (bottom depth) and 3.5” top depth, with the sub mounting baffle/face recessed 2” for a D1 of 5” and 14” of width since with gasket the subs width is a hair over 13”. This comes out to 1.16cf of airspace, probably will add a brace or two and with sub displacement I should be right around 1cf. To put this into perspective:



The foam board I use for mock ups is only 30” wide so the box will be another 4” wide on the right side, and I’ll have to test fit and make sure the recessed portion centers behind the seat and will probably end up needing to tweak it slightly, but overall this would be the front firing shape. To make it rear firing I’d simply carry the angled face across to fill in the recessed portion, and then make a recessed part on the “back” of the box to mount the sub. As I’m writing this, I just realized/remembered I have a JL12W3 in a box I built to JL specs, lo and behold that box is 1.125 cf of airspace which is damn near the same as the box I’ll be building. I’ll pull the JL 12W3 from that box, throw the Wavetech in, and test it front vs rear firing before testing with my mic and deciding if either sounds better. Rear firing should corner load it better but I’m worried about excessive rattling even though I’ve got my rear wall deadened. Front firing more worried about the seat stifling it too much but we’ll see. More to come soon and when I decide on orientation and start building the box I’ll probably start a fresh thread to detail the box build and give exact dimensions etc.

 

This is sounding good, excited to see the results and appreciate your willingness to share your work with us all!

 

I love your efforts!

When I discussed the stealth box design with JL, (as to why rear firing vs down, vs front) they said they tried everything and found the rear firing configuration was what took the cheese for the best output/quality. There's something with the seats that block too much from forward pushing subs and exactly what you said about the corner load was what outperformed other setups. The only thing that rattles in my truck, is sometimes my under seat storage, longbox lids are metal and I can just barely hear it shake itself to certain frequencies.
Also, on a side note. My system's bass is affected by wether or not the bottom of the rear seat is in the raised position.

 

I didn’t get around to testing today, planning to do it tomorrow evening, but that’s exactly what I was thinking/curious about. JL definitely mass produces the only tested/researched enclosures that are vehicle specific that I know of. Obviously if you pay a high end shop for install they’ll test layouts/orientations/enclosures of drivers, but I ain’t rich lol. I had previously done some deadening on the rear wall/window panel but I pulled back the carpet and deadened/added fiber mat underneath the carpet, on the rear wall, and on the back side of the seat belt panels. Need to get some more cld ordered to finish the other plastic trim, but the back is noticeably more solid sounding after 20cf of cld and fiber mat:





Mostly resonix with some leftover NVX from another project.

 

@Snert
I use Cascade Audio Engineering products throughout. It's the best of the best when it comes to environmental enhancement, noise attenuation, and control.




https://www.cascadeaudio.com/




Doors treated inside and out, applied with a single sheet and no seems. All panels completely sprayed and stuffed silent.





Full VB-3 lead plenum coverage from the windshield firewall all floors and transmission tunnel all the way up to the rear window.


https://www.cascadeaudio.com/car_noise_control/vb_3.htm

You can see the lead plenum here...


People say 100% coverage isn't necessary. But if you're like me, and you can hear every last little friggin' noise or rattle, then this is the only way!
I put about $4500 worth of Cascade materials in my truck along with nearly 100 hours of my own time to do full coverage and total control the truck's environment.

My truck is a tomb of silence!!

 

So I for sure got the front firing dimensions figured out, straightforward wedge just had to play around with the top/bottom dimensions and slope to give a gap between the grill and seat support bars:


This would obviously be straightforward to build, I'd add triangles on the front to make full depth like the foam mock up in post #166.

The more difficult option would be rear firing. To mock it up, I pulled the rear passenger seat, laid it down on a table, and was able to shape this mock up of the back of the seat:

Kind of hard to tell from the pic, but due to the seat angle the top and bottom end up being even so that the sub would be mounted 90* to the floor/straight up and down. Similar to the other mockup, the long-ish triangle side portions come out far enough that a butt joint on the outside would leave just enough room for the magnet to clear. Again playing a game of 1/8" increments. Have to decide if the juice is worth the squeeze as far as front vs rear firing as I haven't gotten a chance to test and compare the two orientations yet.

 

Lol it looks like it's hitting but I assure you at the closest spot there's about 1/4-1/2" of clearance, and then the other spot that is somewhat close there's probably an inch or so of clearance. It's tight, but with the grill on the sub it will never go beyond that/no risk of hitting/rubbing. I need to disassemble a raised truck bed plywood box thing I have and use the 3/4" from that to mock up the rear firing enclosure but it's looking like either way will just be able to squeeze in. Not ideal as I know I should be allowing for more room but we're here already and I'm sticking with it for better or worse lol.

 

I was able to mockup/confirm I can indeed get the sub to fit rear firing as well, if not for the grill being 2-1/8” tall and/or with a sub with less excursion/similar mounting depth could definitely fit rear firing better, but regardless I still has ~1/2” or so at its closest point to the rear wall.



The top circled corner is bumped out a bit due to the box sitting on the spare tire/jack tool mounting point, and then the plan would be to have the sub how it’s pictured, but then make the box deeper on both sides of the sub and do some standoffs to keep it from touching the back wall, sort of like the L shapes, and then the triangle piece would essentially fill in the sides by the sub deep enough to the point where I could attach an angled face that matches the slope of the seat backs. Kinda hard to describe it but that’s the gist.

Another pic of the fit/idea:

 

If you get this to work would you be willing to make more or provide you build specs? Also if this was a finished product what kind of air space you looking at. That's some fine work!

 

I’d consider building more but with cost to ship sub boxes it might not be worth it, I’d be willing to share the design for sure though. As far as air space, i’ll have to figure out a way to calculate it but the wedge box I mocked up would be about 1 cf of air space at 34” wide, this should come out to roughly the same because it’ll be about the same dimensions just slightly different due to the recessed sub area. I’ve got the angles of the seat back down so I can play around with the height now and rather than having the top be a flat ~1.5” piece, I may figure out extending this piece up to meet the mounting baffle and eliminate the top part:



which would then make the height more uniform overall.

 

I personally like the idea of a rear fireing sub, by the looks it seem to be safer for the sub if it makes sense, also if you could get a frame mockup and fiberglass it you could possibly gain some sub space.

 

Yeah I considered going the fiberglass route but I’ve never done it. I’ve made a probably 5-10 sub boxes over the years and the last few have been fairly odd shapes with MDF/bondo and they turned out great. Nice thing about this is it could easily be duplicated into a double box like the JL stealth box and if you look at their design it’s very similar just clearly more detailed/molded fiberglass.

 

what state do you live in ?

 

Far north country aka MN lol