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Mass 2012 results (1 Viewer)

Adam Butler

Jan 25, 2002
The Mass is in a 181.5L enclosure with a tuning freq. of 18hz and dual 4" ports. It is not exactly finished yet; I just had to hear what it would sound like. :D I was wondering if it was possible to have a perfectly flat Radio Shack meter? The reason I ask is because using the meter, the frequency response in room at the listening position was pretty much flat. Here are my uncorrected measurements:
Hz/ Db
16 89
20 88
24 89
28 89
32 89
36 88
40 86
44 85
48 84
52 86
56 87
60 87
64 87
68 85
72 86
76 88
80 91
84 88.5
88 88
92 89
96 88
100 85
Well, I think this is pretty darn flat response since measurements were taken at the listening position and with no eq. As I said before these are uncorrected values. So do I really get 105 db at 16 hz? 95.5 db at 20 hz? Is it possible my radio shack meter has a flat frequency response? Please note these measurements were taken in a dorm room at 10:00 pm, or I would have turned it up a little more. ;)
I will try to post some pics of it when it is completely finished. Aside from one of the ports resonating at 32hz (which I will fix soon) I am very happy with the performance. There is no comparing my old JBL PB12 to it.

Jack Gilvey

Senior HTF Member
Mar 13, 1999
Very nice, Adam, that Mass is an amazing driver. Good idea to go with the dual ports.

No, I don't suppose you got a RS meter with correct response. If you've got a typical modern dorm room (cinderblock walls, small), that's probably the best place to get prodigious amounts of room gain. Looks like you've got a good spot nailed.

Dustin B

Senior HTF Member
Mar 10, 2001
Corrected still looks pretty good with some solid room gain down around 20hz:

hz Orig Corrected

16 89 100.5

20 88 95.5

24 89 95

28 89 93

32 89 92

36 88 91

40 86 88.5

44 85 87

48 84 86.5

52 86 87.5

56 87 88.5

60 87 88.5

64 87 88.5

68 85 86.5

72 86 87.5

76 88 89.5

80 91 93

84 88.5 90

88 88 89.5

92 89 90.5

96 88 90

100 85 87

Adam Butler

Jan 25, 2002
Jack, I suppose you are correct. I didn't even think about room gain in my brick walled 15 by 20 foot dorm room. I work in a sheetmetal shop, so what I was thinking about doing was grabbing a steel plate and cutting it to match the size of the top of the sonotube and flaring the steel to match my port holes. Then I will buff the top of the steel to get a chrome-like finish. The rest of the speaker will be covered with black speaker grill cloth. If it turns out well, I may make a base plate of MDF and cover that with a steel plate as well.
The steel will serve a double purpose, too, as it will also add some more weight to my sub. The way it is now, when a quick, hard bass tone hits the sub actually lifts off the floor. There is about a 3.5" gap of air between the Mass and the floor and it still lifts up. Keep in mind that the Mass 2012 alone is 31 lbs! I cant beleive how much pressure this thing creates.
Like I said, I will try to post some pics when I have finally finished it. Thanks for the support guys. I think a new DIY junkie is born. :D

jeff lam

Jun 4, 2001
San Jose, CA
Real Name
Jeff Lam
WOW! How the heck do you get 100dB at 16Hz from a single sub? That's amazing! I like that FR, If I have to have any modes, I would rather they be down low like that rather than in the middle. Congrats!

Adam Butler

Jan 25, 2002
Well, as Jack said that kind of output is defiantely helped by corner loading it in a brick lined room. No connecting hallways or adjoining rooms helps, too. It is a completely enclosed 2400 cubic foot room. Also, the Mass 2012 is no joke of a driver. Here is a link to Audiomobile's specs for the Mass 2012: http://www.audiomobileinc.com/massspecs.htm I've got the 2012 S24. I had to pay a little more for it (okay maybe a lot) but like I said it is in a 181.5L (5.75 ft^3) enclosure made of 4 feet of 18" dia. sonotube and tuned to 18hz with dual 4" ports that are 28.5" long. I will try to burn another test tone CD that goes below 16hz and post the numbers, heck it might still put out major bass at even lower frequencies. I just never needed any tones lower than that because my PB12 would start to cry if given anything that low. Well, actually it was more like a mumble. :D When I played the 16 hz and 20 hz tones on my sonotube, it seemed like everything in my room was shaking. I think I can honestly say that I was scared.
BTW, Jack I would like to compliment you on the PR sub you posted a couple days ago. That finish is awesome!! I hope mine looks at least half as good when it gets finished.

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