25cu/ft dual 15's sub... (1 Viewer)

[Forte_II]

Hi, I need some feed bakc on what WinISD is telling me... Port lenth seems fishy.. Any other observations? Driver : Dayton RSS-390 HF 4 Number of drivers : 2 Box type : Vented Box size : 25.688 ft^3 Tuning frequency : 18.74 Hz Vent : 1 vent(s) 0.75 in length for each 4.00 in round Relative Freq Gain SPL [Hz] [dB] [dB] 10.00 -21.24 68.77 11.00 -17.87 72.14 12.00 -14.76 75.25 13.00 -11.87 78.14 14.00 -9.20 80.81 15.00 -6.75 83.27 16.00 -4.55 85.46 17.00 -2.68 87.33 18.00 -1.19 88.82 19.00 -0.11 89.90 20.00 0.57 90.58 21.00 0.95 90.96 22.00 1.12 91.13 23.00 1.16 91.17 24.00 1.13 91.14 25.00 1.06 91.07 26.00 0.97 90.98 27.00 0.88 90.89 28.00 0.80 90.81 29.00 0.72 90.73 30.00 0.65 90.66 31.00 0.58 90.59 32.00 0.52 90.53 33.00 0.47 90.48 34.00 0.42 90.43 35.00 0.38 90.39 36.00 0.35 90.36 37.00 0.32 90.33 38.00 0.29 90.30 39.00 0.26 90.27 40.00 0.24 90.25 41.00 0.22 90.23 42.00 0.20 90.21 43.00 0.18 90.19 44.00 0.17 90.18 45.00 0.16 90.17 46.00 0.14 90.15 47.00 0.13 90.14 48.00 0.12 90.13 49.00 0.11 90.12 50.00 0.11 90.12 51.00 0.10 90.11 52.00 0.09 90.10 53.00 0.09 90.10 54.00 0.08 90.09 55.00 0.08 90.09 56.00 0.07 90.08 57.00 0.07 90.08 58.00 0.06 90.07 59.00 0.06 90.07 60.00 0.06 90.07 61.00 0.05 90.06 62.00 0.05 90.06 63.00 0.05 90.06 64.00 0.04 90.05 65.00 0.04 90.05 66.00 0.04 90.05 67.00 0.04 90.05 68.00 0.04 90.05 69.00 0.03 90.04 70.00 0.03 90.04 71.00 0.03 90.04 72.00 0.03 90.04 73.00 0.03 90.04 74.00 0.03 90.04 75.00 0.03 90.04 76.00 0.02 90.03 77.00 0.02 90.03 78.00 0.02 90.03 79.00 0.02 90.03 80.00 0.02 90.03 81.00 0.02 90.03 82.00 0.02 90.03 83.00 0.02 90.03 84.00 0.02 90.03 85.00 0.02 90.03 86.00 0.02 90.03 87.00 0.02 90.03 88.00 0.01 90.02 89.00 0.01 90.02 90.00 0.01 90.02 91.00 0.01 90.02 92.00 0.01 90.02 93.00 0.01 90.02 94.00 0.01 90.02 95.00 0.01 90.02 96.00 0.01 90.02 97.00 0.01 90.02 98.00 0.01 90.02 99.00 0.01 90.02 100.00 0.01 90.02 101.00 0.01 90.02 102.00 0.01 90.02 103.00 0.01 90.02 104.00 0.01 90.02 105.00 0.01 90.02 106.00 0.01 90.02 107.00 0.01 90.02 108.00 0.01 90.02 109.00 0.01 90.02 110.00 0.01 90.02 111.00 0.01 90.02 112.00 0.01 90.02 113.00 0.01 90.02 114.00 0.01 90.02 115.00 0.01 90.02 116.00 0.01 90.02 117.00 0.01 90.02 118.00 0.01 90.02 119.00 0.01 90.02 120.00 0.01 90.02

 

[Robert_J]

I get .94 inches. But you will need at least 2 ports. Plus that box is extremely large. Have you looked at the excursion graph to see how much power it takes to reach xmax?

 

[Forte_II]

Well that is a problem for me... I am blind and have to wait for a sighted person to read the graph...

 

[Forte_II]

What about this?

 

[Robert_J]

That graph is way to small for me to read. Do you want a single cabinet or dual cabs? What amp are you using to power this sub? Have you considered sealed instead of ported? What sized room is this going in? Do you know how big a 25 cubic foot cabinet it? It's a large refrigerator. Normally I would make you jump through all of the hoops to learn to use the software. Since you can't fully utilize it, I will definitely help out and the questions above will narrow down the options considerably.

 

[Forte_II]

That graph is way to small for me to read. Do you want a single cabinet or dual cabs?: Single What amp are you using to power this sub?: Samson Class A/B 600w x2 4ohm 1200w x 1 4ohms Have you considered sealed instead of ported?:A good argument may change my mind but I want the most DB between 18hz and 40hz. What sized room is this going in?: 18'x24'x8' open to a Dining/Kitchen and a hallway. Do you know how big a 25 cubic foot cabinet it?: just over 2'x2'x6' internal dim. Normally I would make you jump through all of the hoops to learn to use the software. Since you can't fully utilize it, I will definitely help out and the questions above will narrow down the options considerably: Thanks. I have some experience but the software part is frustrating!

The Drivers are 2 Dayton RSS-390 HF 4's. PRODUCT SPECIFICATIONS Power Handling (RMS) 500 Watts Power Handling (max) 1,000 Watts Impedance 4 ohms Frequency Response 18 to 800 Hz Sensitivity 87 dB 1W/1m Voice Coil Diameter 2.5" Magnet Weight 150 oz. THIELE-SMALL PARAMETERS Resonant Frequency (Fs) 18 Hz DC Resistance (Re) 3.3 ohms Voice Coil Inductance (Le) 1.00 mH Mechanical Q (Qms) 3.10 Electromagnetic Q (Qes) 0.49 Total Q (Qts) 0.42 Compliance Equivalent Volume (Vas) 9.95 ft.³ Mechanical Compliance of Suspension (Cms) 0.28 mm/N BL Product (BL) 14.67 Tm Diaphragm Mass Inc. Airload (Mms) 282.6g Maximum Linear Excursion (Xmax) 14 mm Surface Area of Cone (Sd) 829.6 cm² Thanks for the help.

 

[Robert_J]

I've already helped a guy with this same driver - http://www.hometheaterforum.com/t/297229/dayton-rss390hf-4-15-reference-hf-build With your pro amp that has no subsonic filter, I really recommend going sealed. 4.5 cubic feet net per driver or 9cf if you are building a single box for 2 drivers. Make them opposed like the Epik Subs.

 

[Forte_II]

I have a mini DSP on its way for Bass management. So that is covered... I want every DB of bass I can get out of this driver! So with the miniDSP Do you still think sealed is the way to go? Size is not a issue at all... Thanks.

 

[Robert_J]

The DSP will help flatten the response but this is a sound quality driver not an SPL driver. I have dual, sealed 15's in my home theater and I have never pushed them to their limits. Also, I only have a few hundred more watts than you so the max output of my subs should be very similar to what you have planned. I usually lose my nerve when giving a demo and turn it down before something breaks or my wife throws something at me. Unless you are trying to fill an entire house with bass, you shouldn't need any more output. And if you do, you can upgrade to 18's.

 

[Forte_II]

Thanks Robert I think I will go with the 5.5cu. ft. vented design from the thread you linked above. Thanks agai n. BTW: I have these two subs in a large non optimized enclosure (a Brick fireplace that has been sealed off) and they are loud and hit hard but they just dont reach down far enough...

 

[Robert_J]

That might require some tweaking with the DSP. Since you are willing to go that route, have you looked at REW (Room EQ Wizard)? Home Theater Shack is the place for information on that software and the necessary hardware for it. My sub had no low bass after I first built it. Then I flattened the response with my Feedback Destroyer and now I'm + or - 3db down to 15hz. By going vented, you will probably limit yourself via enclosure tuning to about 20hz as the lowest notes.

 

[Forte_II]

I downloaded UniBox and it is useable for me, well except the graphs. Thanks for the help.