Hey all,
New to the speaker game. I have this Precision Power PC8 8" driver in one of the recommended size sealed enclosures (0.75 cu ft) but it doesnt sound very good; this is for a car stereo application. I did some basic research and d/l winISD to see what this driver was doing. T/S parameters are:
from: http://www.precisionpower.com/ppipdfs/subs/pc81011.pdf
Nominal Power Handling = 200W
Resonant Frequency = 35Hz
Qts = 0.25
Qms = 1.28
Qes = 0.32
Vas = 17.91L = 0.632 cuft
DC Resistance = 3.4 Ohm
Sensitivity 1W/1m = 85.7dB
Linear excursion = +/- 7.98mm
Mms - Total Mass = 59.98g
Sd - Piston Area = 0.0191 sq.m
Bi-Magnet Product = 11.83 TM
Mounting Dia. = 7.125"
Aiming for a Qtc of 0.707 winISD calculates a Vb=0.09 cu ft! Quite a bit different than the recommended sizes of 0.5, 0.75, and 1.0 cu ft.
So I read that lower Qts drivers are better suited to vented enclosures. For vented winISD calculates Vb=0.13 cu ft, tuning freq=57 Hz, but the port lengths are rediculously long (eg. 1.9m for a single 10cm diameter port).
So any suggestions what can be done with this driver for a more 'correct' enclosure or is best for a paper weight? Thanks in advance.
New to the speaker game. I have this Precision Power PC8 8" driver in one of the recommended size sealed enclosures (0.75 cu ft) but it doesnt sound very good; this is for a car stereo application. I did some basic research and d/l winISD to see what this driver was doing. T/S parameters are:
from: http://www.precisionpower.com/ppipdfs/subs/pc81011.pdf
Nominal Power Handling = 200W
Resonant Frequency = 35Hz
Qts = 0.25
Qms = 1.28
Qes = 0.32
Vas = 17.91L = 0.632 cuft
DC Resistance = 3.4 Ohm
Sensitivity 1W/1m = 85.7dB
Linear excursion = +/- 7.98mm
Mms - Total Mass = 59.98g
Sd - Piston Area = 0.0191 sq.m
Bi-Magnet Product = 11.83 TM
Mounting Dia. = 7.125"
Aiming for a Qtc of 0.707 winISD calculates a Vb=0.09 cu ft! Quite a bit different than the recommended sizes of 0.5, 0.75, and 1.0 cu ft.
So I read that lower Qts drivers are better suited to vented enclosures. For vented winISD calculates Vb=0.13 cu ft, tuning freq=57 Hz, but the port lengths are rediculously long (eg. 1.9m for a single 10cm diameter port).
So any suggestions what can be done with this driver for a more 'correct' enclosure or is best for a paper weight? Thanks in advance.
remember cabin gain?
car subs take advantage of the impact that a small cabin has to offer. So with car subs You ought to run a design program to see what size box to use. If you don't have or want to run a simulation then use the largest volume recommended cabinet and then if you find you need a little more umph you can either fire the sub into a corner or just place the cabinet in the corner of your room with the longest diagonal dimension. Regards Moray James.
car subs take advantage of the impact that a small cabin has to offer. So with car subs You ought to run a design program to see what size box to use. If you don't have or want to run a simulation then use the largest volume recommended cabinet and then if you find you need a little more umph you can either fire the sub into a corner or just place the cabinet in the corner of your room with the longest diagonal dimension. Regards Moray James.
Another option would be a Transmission line, I've been using TL's in cars for some time, your's I would put in a tube 8'' in dia by 45'' long, lightly stuffed along the whole length with polyester fill, you'll need to put mesh or a grille on the open end to stop the fill from coming out.
Position the tube at the far back of the car/trunk for best results.
Position the tube at the far back of the car/trunk for best results.
If those parameters are right, a sealed box is useless and I find it hard how any manufacturer could even think about suggesting to use a sealed box. It's power handling will be poor and it will quite severely lack bass and punch. I would go vented, but with Qts that low it's never going to be a stormer.
Re: remember cabin gain?
Looks interesting but beyond my construction resources.
Any details or links on how to go about running a simulation? Is it a strictly virtual exercise or does it involve measuring interior acoustics? Is there shareware software available?
This looks like a doable project. What do you use for tube construction? Can you get away with ABS/PVC piping?
Thanks,
Ron
footstony said:
Looks interesting but beyond my construction resources.
moray james said:
Any details or links on how to go about running a simulation? Is it a strictly virtual exercise or does it involve measuring interior acoustics? Is there shareware software available?
Volenti said:
This looks like a doable project. What do you use for tube construction? Can you get away with ABS/PVC piping?
Thanks,
Ron
/sreten.Re: Re: remember cabin gain?
Yea most of the TL's I've done with 8'' drivers have used pvc pipe, sono tube (used in construction as moulds to make pillars out of concrete) works well too if you can get it, it's like a thick walled cardboard tube.
You don't need to use a tube though, I've made folded lines out of wood that work just as well.
Ron101 said:
Yea most of the TL's I've done with 8'' drivers have used pvc pipe, sono tube (used in construction as moulds to make pillars out of concrete) works well too if you can get it, it's like a thick walled cardboard tube.
You don't need to use a tube though, I've made folded lines out of wood that work just as well.
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Sub resonance box...
just had a look at the Australian site ESP where they run the driver in a very small box to force resonance way up then use a simple EQ to set things staight adjusting for the 12 db per octave roll off. Might be worth looking into for this driver as you loose the big vent pipe and keep it all small.
just had a look at the Australian site ESP where they run the driver in a very small box to force resonance way up then use a simple EQ to set things staight adjusting for the 12 db per octave roll off. Might be worth looking into for this driver as you loose the big vent pipe and keep it all small.
I kind of doubt it...
these drivers get stuck in car trunks in black cars in the summer sun and have the you know what beat out of them and they have to survive all that. I also doubt that you would have to put more tha a couple of hundred watts into one for peaks. I really don't think that overheating would be a problem. If you really had concerns you could always build in a heat sink but that sounds a bit extreem to me.
these drivers get stuck in car trunks in black cars in the summer sun and have the you know what beat out of them and they have to survive all that. I also doubt that you would have to put more tha a couple of hundred watts into one for peaks. I really don't think that overheating would be a problem. If you really had concerns you could always build in a heat sink but that sounds a bit extreem to me.
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