323Alpine
Oct 23 2002, 03:56 PM
Simple question,
if i've found my peak to be at 45Hz car wise do i tune the port to 35hz or so or do i go 50 Hz or so, and why? cause currently i'm tuned to 50Hz and hitting at 45Hz.
thanx
Dave
mistersparco
Oct 23 2002, 04:24 PM
remember, to find your resonant freq u need to use a sealed box otherwise you will get the tuning freq of the ported box, and to my understanding for max SPL you need to tune to the resonant freq of your car.
my guess is that maybe you are tuned to 45hz afterall, which may be to low for that car.
icebreaker
Oct 23 2002, 04:31 PM
you might find that your not tuned to 50hz.
you might also find that your hitting your speakers peak at 45Hz not your cars.
so it could be a matter of tunning your port differently. remember it can take dozens of port area's and lengths to get it right.
have you got some spec's.
of your subs and your box.
i'm talking port area, port length, box volume before and after displacement of the port and sub/
the amount of power your feeding them, assuming your power source is keeping up with the amps current draw.
for me i've found tuning my box, the peak is about 6hz above it. ie. 46Hz, peaked at 52Hz.
and just because everything resonates, doesn't necessarily mean that's the peak or freq you should be aiming to burp at.
if things were that simple, comps would be seeing 90% of competitors breaking the 150's.
[ October 23, 2002, 14:32: Message edited by: icebreaker ]
Bassaholic
Oct 23 2002, 07:13 PM
I agree with icebreaker..
what box (internal) dimensions, port dimensions, approximate position of the box in the car
and the subs specs
(and I'm hoping you are not talking about the frequency that your car shakes the most at...)
[ October 23, 2002, 17:18: Message edited by: Bassaholic ]
QUOTE
Originally posted by Bassaholic:
(and I'm hoping you are not talking about the frequency that your car shakes the most at...)
my van is around 20hz
323Alpine
Oct 23 2002, 07:30 PM
ok here is the deal, i've taken my car to comps and have tried numerous frequencies and 45Hz comes up tops.
the box specs are
3.7cuft
port area 19.5cm x 9.5 cm
port length 8.5cm approx
the subs are inverted so magnet is outside(should i have them inside???)
subs are boot loaded the the port is rear loaded in a sedan
the sub spec are
alpine 10"ZR x 2
Wrms=300
Wpeak=1000
imp=4ohm
dc resistance=4ohm
Fs=34Hz
Vas=1.31 cuft
Qms=6.10
Qes=0.34
Qts=0.32
Xlin=4mm
xmax=16mm
voice coil diameter=75mm
magnet weight=1.5kg
driver physical volume(top mount)=0.1cuft
driver physical volume(bottom mount)=0.13cuft
that is all i have.
if u can determine what port freq i should use this would be great.
[ October 23, 2002, 17:31: Message edited by: 323Alpine ]
Bassaholic
Oct 24 2002, 01:37 AM
QUOTE
Originally posted by KraSE:
quote:
Originally posted by Bassaholic:
[b]
(and I'm hoping you are not talking about the frequency that your car shakes the most at...)
getting a bit OT, but mine is too
it has that sweet sound of nothing, plus a really bad banging sound coming from the hatch and flexing panel sounds :-)
[ October 23, 2002, 23:37: Message edited by: Bassaholic ]
QUOTE
Originally posted by Bassaholic:
quote:
Originally posted by KraSE:
[b] quote:
Originally posted by Bassaholic:
[b]
(and I'm hoping you are not talking about the frequency that your car shakes the most at...)
getting a bit OT, but mine is too
it has that sweet sound of nothing, plus a really bad banging sound coming from the hatch and flexing panel sounds :-)[/b]
strange i get the same sounds and about 1 cm one way X-max on my dash
Bassaholic
Oct 24 2002, 02:03 AM
does the port use a box wall as a port wall? (if it does, then the tuning is *about* 47hz, if not, then *about* 52hz)
I'd guess that the tuning frequency would be best between 38-40hz, so I'd try 38hz (its better to tune slightly too low, than slightly too high)
[ October 24, 2002, 00:16: Message edited by: Bassaholic ]
ripped
Oct 24 2002, 11:54 AM
na, it's a rect. port in the middle of the box, not slot port.
icebreaker
Oct 24 2002, 12:08 PM
prob getting alot of cancelation.
i would wall off the chambers, and use 2 ports
that is a very tiny port also.
might pay to go bigger surface area, and longer port.
im surprised that no one has said this yet but DONT play sinewaves under the tuned frequency. Anything under this and the subs have almost no power handling (eg very high efficiency) and you run the risk of damaging your subs.
Try to get a sealed box and work out the res frequency of ya car. Then port that box to peak at the freq (you need a speaker design program or a friend to work this out) that the car peaks at. Bigger surface area ports will give you better results as their is less of a peak.
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