18" Sub box for Mobile DJ help!!!
Hey Guys,
Newbie here, I want to build a box similar to this:
http://pro-audio.musiciansfriend.com/product/Yamaha-SW118V-Club-Series-V-Subwoofer?sku=601207
I have already purchased all the hardware necessary and the woofers. I have some car audio box building experience. The problem is I only know how to make sealed boxes. I never learned vented or ported. I have all the specs for the woofer. Now I just need direction on planning for the box. Any help would be greatly appreciated. Oh I am building two and using a QSC RMX 1850HD amplifier running at 4 ohms stereo.
Chuck
Peavey 1808-4 BWX 18"
Impedance: 4 Ohms
Power capacity: 2000 W Peak 1000 W Program 500 W Continuous
Sensitivity: 97.5 dB / 1 W 1 m
Usable freq. range: 35 Hz ~ 1 kHz
Cone: Kevlar® impregnated cellulose
Voice coil diameter: 4.0" / 100 mm
Voice coil material: Aluminum ribbon wire Polyimide-impregnated fiberglass former Nomex® stiffener Solderless diffusion welded OFHC copper leads
Net weight lb. / kg: 18 lbs. / 8.2 kg
Znom (ohms) 4
Revc (ohms) 3.47
Sd (Square Meters) 0.1237
BL (T/M) 13.94
Fo (Hz) 38.9
Vas (liters) 311.7
Cms (uM/N) 143.4
Mms (gm) 116.6
Qms 10.215
Qes 0.509
Qts 0.485
Xmax (mm) 2.0
Le (mH) 0.16
SPL (1W 1m) 97.5
No (%) 3.50%
Vd (cu. in. / ml) 29.5 / 483
Pmax (Watts pgm.) 1000
Disp (cu. in. / ml) 228 / 3737
Hey Guys,
Newbie here, I want to build a box similar to this:
http://pro-audio.musiciansfriend.com/product/Yamaha-SW118V-Club-Series-V-Subwoofer?sku=601207
I have already purchased all the hardware necessary and the woofers. I have some car audio box building experience. The problem is I only know how to make sealed boxes. I never learned vented or ported. I have all the specs for the woofer. Now I just need direction on planning for the box. Any help would be greatly appreciated. Oh I am building two and using a QSC RMX 1850HD amplifier running at 4 ohms stereo.
Chuck
Peavey 1808-4 BWX 18"
Impedance: 4 Ohms
Power capacity: 2000 W Peak 1000 W Program 500 W Continuous
Sensitivity: 97.5 dB / 1 W 1 m
Usable freq. range: 35 Hz ~ 1 kHz
Cone: Kevlar® impregnated cellulose
Voice coil diameter: 4.0" / 100 mm
Voice coil material: Aluminum ribbon wire Polyimide-impregnated fiberglass former Nomex® stiffener Solderless diffusion welded OFHC copper leads
Net weight lb. / kg: 18 lbs. / 8.2 kg
Znom (ohms) 4
Revc (ohms) 3.47
Sd (Square Meters) 0.1237
BL (T/M) 13.94
Fo (Hz) 38.9
Vas (liters) 311.7
Cms (uM/N) 143.4
Mms (gm) 116.6
Qms 10.215
Qes 0.509
Qts 0.485
Xmax (mm) 2.0
Le (mH) 0.16
SPL (1W 1m) 97.5
No (%) 3.50%
Vd (cu. in. / ml) 29.5 / 483
Pmax (Watts pgm.) 1000
Disp (cu. in. / ml) 228 / 3737
Re: 18" Sub box for Mobile DJ help!!!
Greets!
OK, then build a 'sealed' box that's ~222.64 L net (i.e. after factoring in the volume loss due to the driver, vent and any bracing) and vent it with a 20.32 cm diameter pipe (or some other duct shape of equivalent area) by 20.32 cm long to get a ~Fs tuning with a ~30 Hz F10 sitting on a solid, non 'floating' floor. Line one side, top and back panel with ~2.54 cm acoustic fiberglass insulation or similar to smooth out its vent induced HF 'hash' (resonances) above ~500 Hz.
BTW, for my records, are these published or measured specs?
GM
Greets!
OK, then build a 'sealed' box that's ~222.64 L net (i.e. after factoring in the volume loss due to the driver, vent and any bracing) and vent it with a 20.32 cm diameter pipe (or some other duct shape of equivalent area) by 20.32 cm long to get a ~Fs tuning with a ~30 Hz F10 sitting on a solid, non 'floating' floor. Line one side, top and back panel with ~2.54 cm acoustic fiberglass insulation or similar to smooth out its vent induced HF 'hash' (resonances) above ~500 Hz.
BTW, for my records, are these published or measured specs?
GM
Attachments
Sheesh! That's too loud for banquet, etc. rooms, school auditoriums, etc.. Back when I helped with such apps, the SPL was based on the drum kit regardless of room size, so 115-120 dB was plenty for the <100 Hz BW. Big outdoor events requires more of course, but these aren't 'mobile DJ' events.
And to think I use to take a lot of verbal abuse for waste of money/space 'overkill' designs that I did to keep distortion low and now it seems they would be drowned out with SPLs high enough to permanently damage/distort the ears. Oh well, I know how to do 'loud' for a given driver and the BMX in a band-pass should peak on the far side of 130 dB in the ~50-100 Hz BW even with some thermal power compression.
GM
And to think I use to take a lot of verbal abuse for waste of money/space 'overkill' designs that I did to keep distortion low and now it seems they would be drowned out with SPLs high enough to permanently damage/distort the ears. Oh well, I know how to do 'loud' for a given driver and the BMX in a band-pass should peak on the far side of 130 dB in the ~50-100 Hz BW even with some thermal power compression.
GM
So am I screwed or what? From the posts I read, I either chose the wrong woofers or when i put 500w RMS to these puppies they are going to go bye-bye. I have my outer box measurements as
H=28in
W=24in
D=25-1 for grill placement so really 24in
3/4 inch wood
With a vent on the very bottom that is 4in high by 17in deep.
I am calculating 7.75 cu ft and tuned at 36 hz.
Please advise as I just got the woofers in today!
H=28in
W=24in
D=25-1 for grill placement so really 24in
3/4 inch wood
With a vent on the very bottom that is 4in high by 17in deep.
I am calculating 7.75 cu ft and tuned at 36 hz.
Please advise as I just got the woofers in today!
Based upon the parameters the Peavey Lowriders look like a far better choice. A little less efficient but better suited for basreflex in PA-aplications and 4 times the Xmax.
If you're using a sufficient high pass (30 Hz or up) you could use the loudspeakers in parallel at 4 ohm bridged, as supposably the QSC is 2 ohms stable. But even using them at 8 ohms stereo, personally I would prefer the low riders.
Best regards Johan
If you're using a sufficient high pass (30 Hz or up) you could use the loudspeakers in parallel at 4 ohm bridged, as supposably the QSC is 2 ohms stable. But even using them at 8 ohms stereo, personally I would prefer the low riders.
Best regards Johan
ChuxAudio said:
At 500 W with this box alignment, oh yeah!
Put the LoRider in this alignment though and based on published specs, then with a 'rumble' filter to protect it below Fb you're good to go all the way up to its 1600 W rating which with thermal power compression should still yield a ~125 dB/m dynamic range.
GM
Thank you everyone for saving my butt. I called the company and arranged to have them replaced with the Low Riders.
GM-
I have a DBX 223XL crossover and a BBE 882i sound maximizer that I will be using in my rig. Do you still think I need a rumble filter and if so, what freq. should it be cut off at? I did some research into it because I never heard of one before. Thanks again.
Chuck
GM-
I have a DBX 223XL crossover and a BBE 882i sound maximizer that I will be using in my rig. Do you still think I need a rumble filter and if so, what freq. should it be cut off at? I did some research into it because I never heard of one before. Thanks again.
Chuck
You're welcome!
Yeah, I'm dating myself mentioning a filter to protect speakers from TT 'rumble'.
I'm not current with all the latest electronics, especially prosound, but as long as there's an EQ or adjustable high pass XO to cut the <30-35 Hz BW at least 12 dB it should be enough as I doubt your source material has much dynamic range below 40 Hz.
GM
Yeah, I'm dating myself mentioning a filter to protect speakers from TT 'rumble'.
I'm not current with all the latest electronics, especially prosound, but as long as there's an EQ or adjustable high pass XO to cut the <30-35 Hz BW at least 12 dB it should be enough as I doubt your source material has much dynamic range below 40 Hz.
GM
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