[rs16iandy]

hi im new to all this i have a nht 1259 subwoofer. im planning to use a stuffed 3.5 cu.ft sealed box is this the right way to go about it? my main question is should i design the box down firing or front firing what are the pros and cons?
cheers andy

 

[rs16iandy]

Re: nht 1259 build help

im now thinking a sono tube is the way forward....

 

[Mike P.]

Re: nht 1259 build help

Hi Andy, is this sub for HT?

 

[rs16iandy]

hi mike the main use will be ht thanks for your reply. andy

 

[Mike P.]

The recommended box size for the sub is 3.5 to 5 cubic feet sealed. You can expect to get down to about 30Hz, 25 hz if you boost the low end, according to Madisound.

http://www.madisound.com/catalog/product_info.php?products_id=1402

There won't be any difference in output between front or down firing, the advantage of down firing is it offers protection for the sub, a good thing if you have parties or small children. What amp will you be using with the sub?

 

[rs16iandy]

for the time being i will be using a 130w rms samsung amp we only have a small room and it powers my throw together sub well. i have modeled it on a fully stuffed 3.7cu ft sealed box -ldB at 30Hz and
-6dB at 20Hz the is only a 1dB gain at 20Hz at starting a 5 cu ft is this right.
cheers andy

 

[Mike P.]

Post the parameters for the sub if you don't mind.

 

[rs16iandy]

Fs 20.13 Hz
Nomi nal Im ped ance 4 W
Mmd 104.33 Grams
Cms 565.17 m/n
Vas 195.1 Liters
Re 3.524 W
Leap Krm 4.033 m W
Leap Kxm 11.829 mH
Leap Erm 0.756
Leap Exm 0.727
vcL 1.09 mH at 1K
Bl 8.472 Tm
Qms 4.413
Qes 0.663
Qts 0.576
Voice Coil Height 34 mm
Air Gap Height 8 mm
Xmax 13.0 mm Peak
SD 0.0493 m2
Sur round Rub ber
Frame Cast
Cone Material Poly pro pyl ene
Mag net 59 oz.
Voice Coil 50 mm
Music Power 300 Watts
Sen sitivity 89 dB 2.83V/1m

 

[Mike P.]

A 3.5 cu.ft box stuffed at 1 pound per cu.ft. will give a 10% increase in volume. So the sub would "see" 3.85 cu.ft. Here's the SPL graph with 130 watts input power.

Here's the cone excursion graph. 130 watts puts you a couple of mm over Xmax but the sub should handle that.

 

[rs16iandy]

that isnt quite what i was hoping for is that inclulding room gain.

 

[Mike P.]

No room gain in the graph. There won't be much room gain between 30 and 20 hz. If you're looking for HT low end extention you should consider another sub.

 

[rs16iandy]

i have a pair of old cerwin vega svc15's (hed) that i had in my car but i cant find any specs for them plus i thing the fs is high

 

[Mike P.]

What's the model number of the CV HED's?

 

[rs16iandy]

hed-15
silver cone with red oval in the center.

 

[digital desire]

All that is left after turning my 1259 into an HT sub.......
'Nuff said

 

[Mike P.]

svc 15

Does it look like this?

http://www.sonicelectronix.com/pictures.php?id=274

 

[rs16iandy]

thats the one hed-15 4 ohm svc.

if i was to build a sono sub what distance should be left between the floor and the driver?
cheers andy

 

[rs16iandy]

All that is left after turning my 1259 into an HT sub.......
'Nuff said

i might have to rethink this project. im trying to make the best of what i have. we only have a one bedroom flat so i dont need a realy powerfull sub 100 rms would shake this place apart lol

 

[Mike P.]

Found the Specs. It has a limited Xmax of 8.5 mm. In 10 cu ft. tuned to 16 hz it will reach Xmax with 60 watts. It will produce 103 db at 20 hz, plus room gain. Porting would be one 4 inch port 10.25 inches long.

 

[rs16iandy]

so what is the best option the 1259 or the cv?

i havent realy got room for 10 cu ft lol

I did look at a jbl 1514

REVC (OHMS) 3.80
VOICE COIL [email protected] 1KHZ: LEVC (MH) . 3.05
DRIVER RADIATING AREA: SD (IN2) . . . . . . . . 128.7
SD (M2) . . . . . . . 830.00
MOTOR FORCE FACTOR: BL (TM) . . . . . . . . 17.13
COMPLIANCE VOLUME: VAS (FT3). . . . . . . . . 5.42
VAS (LITERS). . . . . 153.50
SUSPENSION COMPLIANCE: CMS (μM/N) . . . . 156.00
MOVING MASS, AIR LOAD: MMS
MD
(GRAMS) . . . 257.00
MOVING MASS, DIAPHRAGM: M (GRAMS) . . . 243.00
FREE-AIR RESONANCE: FS (HZ) . . . . . . . . 25.10
QMS . . . . . . . . . . . 7.08
QES . . . . . . . . . . . 0.52
QTS . . . . . . . . . . . 0.49
MAGNETIC-GAP HEIGHT: HAG (IN) . . . . . . . . . 0.31
HAG (MM) . . . . . . . . 8.00
VOICE COIL HEIGHT: HVC (IN) . . . . . . . . . 1.45
HVC (MM). . . . . . . . . . 37
MAXIMUM EXCURSION: XMAX (IN). . . . . . . . .0.57
XMAX (MM) . . . . . . 14.50

mounting depth
6-13/16" (172mm)
cutout diameter
13-15/16" (354mm)
outer diameter
15-5/16" (389mm)

cheers andy