Tunning a box (car audio into home audio)
06-23-2003, 12:09 PM
#1
1000 Watt CAFz'r
Thread Starter
Join Date: Apr 2002
Posts: 1,089
My car is ruinned I sold almost everything else and all I really have left besides install stuff is my fronts and rears.
I am going to take my fronts and rear car speakers and turn them into a set of home tower speakers. 1 5/14 and 1 6x9 in each. total resistance 8 ohm.
The plan is this
inside demensions
6x9 chamber
11" wide x 17" deep x 27" high
for a total for 2.92 cubic feet plus port at the bottom
the 5 1/4 chamber
11" wide x 17" deep x 7" high
for a total of .75 cubic feet sealed with the tweet surface mounted.
The question I have is this what should the port length and area be to tune to 50Hz?
The other question I have is why does the port always face the back in home audio speackers?
Project should start today or tomorrow.
I am going to take my fronts and rear car speakers and turn them into a set of home tower speakers. 1 5/14 and 1 6x9 in each. total resistance 8 ohm.
The plan is this
inside demensions
6x9 chamber
11" wide x 17" deep x 27" high
for a total for 2.92 cubic feet plus port at the bottom
the 5 1/4 chamber
11" wide x 17" deep x 7" high
for a total of .75 cubic feet sealed with the tweet surface mounted.
The question I have is this what should the port length and area be to tune to 50Hz?
The other question I have is why does the port always face the back in home audio speackers?
Project should start today or tomorrow.
06-23-2003, 12:34 PM
#2
Guest
Posts: n/a
Using this: http://tools.autoaudio.com/ventcalc/ for 2.9cuft tuned to 50hz using a 4" diameter port you will get a length of 1.73".
Usually the port faces the rear for 2 reasons:
1) If there is any port noise it will be less noticible.
2) The close proximity of the vent to the wall will help boost the bottom end.
Usually the port faces the rear for 2 reasons:
1) If there is any port noise it will be less noticible.
2) The close proximity of the vent to the wall will help boost the bottom end.
06-23-2003, 01:13 PM
#3
50 Watt CAFz'r
Join Date: Mar 2003
Posts: 359
Ported boxes to the rear are good as well because it keeps the kids from throwin there toys in the port.
Nothing worse then trying to fish something out threw the port hole.
Nothing worse then trying to fish something out threw the port hole.
06-23-2003, 02:19 PM
#4
1000 Watt CAFz'r
Thread Starter
Join Date: Apr 2002
Posts: 1,089
is there NE advantage yo using a large or smaller diameter port?
I understand that the length of the port changes with the diameter and obviously it is good to stay with standard sizes to buy the stuff but is it better to have a longer and larger port tuned to 50 hz then a shorter smaller port tuned to 50HZ.
I assume using that program I can just calculate the area of the circular port and make a square port with the same area and same length?
I understand that the length of the port changes with the diameter and obviously it is good to stay with standard sizes to buy the stuff but is it better to have a longer and larger port tuned to 50 hz then a shorter smaller port tuned to 50HZ.
I assume using that program I can just calculate the area of the circular port and make a square port with the same area and same length?
06-24-2003, 12:51 PM
#5
Guest
Posts: n/a
Generally you should try to keep port lengths under 24" and port area around half of the area of the cone or less. Generally the more area the better.
Yes just keep the area of the rectangle the same as the circle and the length will stay the same. close enough.
Yes just keep the area of the rectangle the same as the circle and the length will stay the same. close enough.
06-24-2003, 01:18 PM
#6
0 Watt CAFz'r
Join Date: May 2003
Posts: 30
rectangular vent length
Np = # of ports, W1 and W2 are the two widths of the port ( W1 has to be the same orb igger than W2 or youll have problems!) You'll need a scientific calculator, Ihope this helps the "close enough" thing
Vent Length= (51.26/Fb) ^2 * W1 * W2 / Vb - 1.13 W2 * (Np * W1/W2) ^0.25
Np = # of ports, W1 and W2 are the two widths of the port ( W1 has to be the same orb igger than W2 or youll have problems!) You'll need a scientific calculator, Ihope this helps the "close enough" thing
Vent Length= (51.26/Fb) ^2 * W1 * W2 / Vb - 1.13 W2 * (Np * W1/W2) ^0.25
06-24-2003, 04:34 PM
#7
Guest
Posts: n/a
Is there a problem?
Where's your 4%? Do you even know why you 'technically' should add the 4%? And how about you explain the differences in surface drag between wood and plastic pipe and the effects the differing coefficients of friction make on air speed and the resultant vent lengths.
OR you can call it 'close enough'.
Where's your 4%? Do you even know why you 'technically' should add the 4%? And how about you explain the differences in surface drag between wood and plastic pipe and the effects the differing coefficients of friction make on air speed and the resultant vent lengths.
OR you can call it 'close enough'.
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