Get my HD3C15 today

[TheFiverMan 10+ year member]

3.5cf tuned to 35hz with 3 4" aeros //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Jdizzle 10+ year member]

I know this is prolly noobish, but whatever i gotta learn somehow, how does changing the port area effect anything?
Does it lower/higher tuning of the box?

And what exactly do you mean by the port area, is that like how long the port is or something?

port area = widthx height of the port if you change the port area without changing port length it'll change tuning

 

[Skip01 5,000+ posts]

vids of it without sub shots?

Play Lil John - Throw it up to....i wanna see it on all notes

 

[Jdizzle 10+ year member]

box tuning is decided on the port area and the length of the port..not just one or the other

 

[IgnoreMe 5,000+ posts]

i see Prochobo in here....got any advice?

 

[Skip01 5,000+ posts]

i see Prochobo in here....got any advice?

I still show his vid to people when they say 40hz wont hit the lows.....his vid shall inspire all

So we will watch it again: http://youtube.com/watch?v=ZH05RELAA38

 

[IgnoreMe 5,000+ posts]

I still show his vid to people when they say 40hz wont hit the lows.....his vid shall inspire all

So we will watch it again: http://youtube.com/watch?v=ZH05RELAA38

no doubt lol

 

[Jdizzle 10+ year member]

holy **** hella flex for a single 15

 

[tommyk90 5,000+ posts]

yea i was gonna scale the box down to 3.8-4 cubes @ 36hz ( i just cant bring myself to tune to 40hz even though AQ suggests it) //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif. however i wasnt going to scale down the port area. that will be something i will try on this next box for sure. you know your DD subs, and considering the similarities between the HD series subs and some DD subs, i think i will take your advice. unfortunatly i cant really afford the aeros right now //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

Ok, no aeros is fine, though i still think you should bring down the port area. Less port area will help control cone movement as well and in some cases can actually increase output, especially in the lower frequency range.

 

[IgnoreMe 5,000+ posts]

Ok, no aeros is fine, though i still think you should bring down the port area. Less port area will help control cone movement as well.

i think you might of misunderstood me. i meant i wasnt originally planning to cut the port area down (just decrease box volume and raise tuning), but i will now, based on your recommendation //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[IgnoreMe 5,000+ posts]

hey wattslock187, you still want that mag? sorry bro i was banned for a week, which is why i couldnt get in touch with you or bump my thread.

 

[tommyk90 5,000+ posts]

i think you might of misunderstood me. i meant i wasnt originally planning to cut the port area down (just decrease box volume and raise tuning), but i will now, based on your recommendation //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

A smaller box and higher tuning with that same size port wouldn't be any better, IMO.

 

[bimma85 5,000+ posts]

specs on the site are 4.5 @ 40hz. im sitting at 4.5 @ 33hz. seems my issue would be even worse when trying to play under tuning (especially with such a high tuning) like AQ says the HDC3 is designed to do.

where does it say that? Only thing I see is where they recommend 4.5 cubes gross and no tuning recommendation.

 

[IgnoreMe 5,000+ posts]

A smaller box and higher tuning with that same size port wouldn't be any better, IMO.

i started to think that, but i managed to convince myself that maybe it was a issue internally with this box, rather than the actual size/port area/tuning.

im starting to think other wise.

 

[IgnoreMe 5,000+ posts]

where does it say that? Only thing I see is where they recommend 4.5 cubes gross and no tuning recommendation.

honestly, i got the tuning info from this website based on what other people have done.

this is from the website. as you can see the bolded part says 40hz. im thinking people were like "well they are calculating the box around a 40hz tuning, so they must recommend 40hz". they basically go with you step by step in designing a box for their woofer, and end up with 40hz, so im guessing people just ran with it, and thats how the "recommendation" spread. but i dont know. i thought i read that DJ posted that info, and then i know others have just compared it to the DD subs and due to the similarities, they recommend the 40hz tuning. you know how the forums work lol.

How To Calculate Your Port Size.

The box port can be calculated with a simple formula. Box volume in cubic feet X 16 (the amount of port area in square inches per cubic feet of box volume). For example, 3.4 cuft X 16 sqin= 54.5 square inches of port area. Try to stay within 10% of this number.

The port length should be 16 inches deep. This tunes the boxes to about 40 Hz.

How To Make A Slot Port

The easiest and most effective way to build a port is to use a slot shaped port that uses 3 sides of your enclosure as port walls. If the port is located at one end of the box, only one additional piece of wood is required to complete the port. The additional piece of wood should be spaced off the end of the box.

The port area is in square inches, meaning it takes height times width to calculate total area. A port 4 inches high by 4 inches wide would calculate as 4 X 4= 16 square inches.

In our example box, we have an inside height of 14.5 inches. To calculate the slot width that would make a total area of 54.5 square inches, and we use 14.5 inches as the height: divide 54.5 by 14.5= 3.76. Round that figure to nearest ¼ inch, and you get an offset measurement of 3 ¾ inch wide. The slot port would be 3 ¾ inches wide by 14 ½ inches tall.

You don’t have to get too critical about the box and port volume, a good rule of thumb is that if you stay within 5-10% of calculated volumes, there will be very little if any audible effects.

Port Length Obstructions

Some port lengths do not allow for 16-inch port depths without some sort of modification. The rule of thumb is not to let the end of the port get any closer to the back wall than the width of the port. So back to our example, we have an internal box depth of 12.5 inches. We need a 16-inch deep port. We will have to bend the port along the back wall to get the full port length. To calculate where to make the bend, subtract the port width from the inside box depth. 12.5 – 3.75=8.75. We must bend the port at 8.75 inches, then continue the port parallel to the back wall for an additional 7.25 (8.75+7.25=16).

You now have an L shaped port totaling 16 inches in depth.

 

[IgnoreMe 5,000+ posts]

just got a pm from DJ. says to reduce port area to 15-16" per cube and tune to 38-40hz and to center the sub, instead of having it near the port wall like it is.

hey dj while you're in here, do you still recommend the 4.5^ft volume?

 

[DJL 10+ year member]

I like 4 cubes myself, but that's just me.

 

[tommyk90 5,000+ posts]

just got a pm from DJ. says to reduce port area to 15-16" and tune to 38-40hz and to center the sub, instead of having it near the port wall like it is.
hey dj while you're in here, do you still recommend the 4.5^ft volume?

15 square inches? Thats entirely too small. Thats about equivalent to one 4" aeroport, WAY too little for a 15".

Having the sub off to the side is fine actually, I'm guessing you did that to move the sub farther away from the end of the port (inside the box)? If so, I do the same thing.

 

[Skip01 5,000+ posts]

just got a pm from DJ. says to reduce port area to 15-16" and tune to 38-40hz and to center the sub, instead of having it near the port wall like it is.
hey dj while you're in here, do you still recommend the 4.5^ft volume?

Center the sub?.....i always thought it was best to have it over the port...hence CRX style boxes?

Is this only with sub back port back?

 

[DJL 10+ year member]

Tommy that's 15-16 sq'' per net cubic foot of box volume