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View Full Version : Tuning box freq.



SVTLightning01
05-01-2006, 06:57 PM
Im a newb and had no idea how indepth audio goes. My setup right now is

1 DA D610D4
PA VX900D @ 2ohm load
1 Farad Cap
Kenwood DDX-7017
Pioneer 6x8 - Not amped.

Im pushing about 650W rms

I recently had a custom box made for my lightning. Its a single 10" downfiring box. What is the easiest way to determing the freq the box is tuned for?

SVTLightning01
05-01-2006, 07:56 PM
Using an online calc, i determined the box to be 1.87 cu. ft. Now my question is, after i determine how long/wide the port is, how does it affect internal volume of the box? DO i subtract it from total box volume?

watts
05-01-2006, 08:09 PM
You need to add the the volume that the driver occupies (magnet structure and cone assembly) and volume of the port (You need to include the wall thickness of the port.) to the 1.87 ft^3. This will give you your total box volume.

SVTLightning01
05-01-2006, 08:16 PM
Its looking like my box is way to big for the sub im using. DA recommends 1.25 cu. ft. Doesnt look like im anywhere close. How much of an affect will the extra space have on sound?

watts
05-01-2006, 08:21 PM
You might be able to turn it to your advantage depending on how far off you are. You may be able to extend the port and extend the low frequency response. If you are building something you want hit super low and hard for around town you may be able to make what is called a extended bass shelf alignment but I am not entirely sure you have gone wrong. where can I find the specs for your drivers. who makes them and what model are they.

Where did the 1.87 ft^3 come from? The total volume shold be Total Box Volume=1.25ft^3+(Cone & Magnet Structure)ft^3+(Port Volume)ft^3

You should use 1.25ft^3 for the volume in your port calcs.

Check with the manufacture for the cone and magnet structure volume.

SVTLightning01
05-01-2006, 08:38 PM
www.diamondaudio.com i have a d610d4 (10" DVC 4 ohm)

Edited for wrong url.

SVTLightning01
05-01-2006, 08:47 PM
i have been reading up on making a fiber box. It looks **** near impossible to calculate volume on those. I might take on a custom project. Going of your earlier post.....why would you add the driver displacement to the box volume? It seems like it would make more sense to subtract it because of mass of the woofer frame/magnet. Thanks for your help.

watts
05-01-2006, 09:34 PM
Off the top of my head. To calculate a complex box volume you usualy have a expensive audio measurement system like LEAP or CLIO. You can measure the impedance function of the enclosure with the ports sealed of and then measure it again with the ports open then calculate the box compliance and use the volume to air compliance of sub and calculate the box volume. This is the most acurate way to do it. If you realy want to get technical about it and shell out some bucks get you a bag of packing penuts and a half a cubic foot box and measure out how many penuts fit into you enclosure.

You need to add to the box volume to expand for the space ocupied by the drivers magnet and cone structure and you do the opposite if you invert the driver (account for cone and dust cap).

Be careful about using the term driver displacement. Typical driver displacement (represented by Vd) is the effective cross sectional area (Sd) of the cone multiplied by the maximum displacement of the woofer (Xmax).

What I am referring to is if you submerge the driver in water to the top of the rim magnet down and measure the volume of water displaced.

etc.

Vd=Sd*Xmax

SVTLightning01
05-02-2006, 05:18 PM
After doing alot of research on my issues....i dont think my .4 cubes will make much of a difference. I did however, adjust my gain/voltage with the sticky. I noticed a switch that i can switch my input voltage from 5-8v or xxx-2v. This switch was on the low setting. I do know my deck has a higher output than that. So i switched it over, and i did the gain setting with the voltmeter. It doesnt sound as it should, so i think i will set it by ear. The settings were way more than the other setting. So hopefully my sound will improve. It definately sounds better than before. Before it sounded as if my sub was maxing out, or amp was clipping. Ill update more when i can get away from the house and crank it.