Advanced Discussion

So, what is the cause of "moving air"? There are two possibilities in my mind that I think would create this. #1. Air Displacement from the motion of the moving cone of the subwoofer. #2. Actual pressure (sound waves) moving the air inside of the car. In scenario #1 the key to moving the most air would be to have the most cone area, the most excursion of the subwoofers and to have a sealed box (ports have an opening in them so technically a port would help the equalization of air pressure inside of the car) This would also explain why Randy Kubek pretty much has a mobile wind tunnel because he has always ran sealed boxes. ( for reference) In scenario#2, there is much …

So Im tryin to come up with a design for my 18's and im stuck.. I can either have 122.5 inches of port at 5.5 cubes at 34hz or 70inches of port at 7.4 cubes at 28hz im leaning towards the 1st one or i can have even more space and just use aero ports thoughts?

I have a f150 std cab and im about to do a blow threw .. i only have room top to bottom for 12's but if i ever wanted to go bigger i have a idea how i could make it work. I just have not seen many people or any one ever build a box like this. Now t-lines work off of 1/4 wave and a 6th order is like a ported box with ports on both sides of the sub.. what would happin if i built a box and made it were there was port on the front and back of the sub like a 6th order but the ports were all 1/4 wave like a t-line just front and back.... the box would be huge because of the simple fact that each port would be around 9 feet long lol but hey i got a long bed truck so it dont m…

Hi everyone, I have a dual 2ohm that is 1200 wrms and 2000 peak. Can I run a 800wrms amp or more on each vc? the sub is PG titanium elite (proven power hogs). How common of a practice is this? The reason I ask is because it seems like that application would use the woofer to the fullness of its potential. Later everyone

First off I have two alpine pdx 600.1amps each amp is producing over 700 watts I want to buy 2 fi ssd 12s run 1 off each amp anyway here's the questions when ordering I'm asked about flatwind coil yes or no copper coil yes or no and bo power. Could someone explain this to me and what I should do to answer these questions thanks

Sorry my drawings are a little crude, but I'm taking an auto electrical class and some of our discussions got me thinking. I did a search and found nothing on it, but would like some input. I figured this would be a better place to post it than ca.com With series wiring, once power has passed through a load, there is a voltage drop depending on all 3 factors, Voltage, amperage, and ohms of resistance. With parallel wiring, each leg of the circuit gets the same voltage, only amperage and resistance fluctuate (they SHOULDN'T fluctuate differently in an audio setup, but if all coils are identical, theoretically, they all do the same thing) Remember, these are all theory, …

Hey all , I've got this AA mayhem 15 inch dual 2 ohms wired to 1 ohm , now BBpro6 tells me that the minimum impedance under load will be 2,05 ohms in the box its playing in , is this what the amp will see or will the amp still see the Re of 0,7 ? thanks in advance .

http://www.hotrodders.com/forum/alternative-lizard-skin-103610.html Micro ballons http://www.heatshield-r20.com Anyone had experience with it? It looks interesting.

I need help with design enclosure for BMW trunk, i need to get bass to cabin. Maximum height 16" Maximum width 35,2" Check this topic to see what i have there right now: HERE Subwoofer: JBL GTO 1514, 15 inch.

My buddy recently bought a 94 Cadillac Seville, and the radio wiring was so ghetto rigged so he went to rewire everything. While wiring, something shorted and now his instrument cluster will not work at all. We pulled the dash apart and tested the power leads and the would get power right before the fuse blew and all the accessories worked fine without issues. So we figured theres a short in the factory wiring. We bypassed all the factory wiring and and gave it constant power right off the ignition and fused it the same as the factory fuse size. Still blowin fuses. The problems arose when messing with the factory radio. The radio would cut out at medium volumes. We took a…

I've been toying with the idea of using a horn in a spl application (one note wonder, as efficient as possible) for a few weeks now.. Instead of a regular wall, with the woofers and port on the wall, me and a friend had the idea of using a horn, with the opening as the whole front of the wall. It would be a front loaded horn, exponential, loaded with some sort of efficient pro-audio woofer, not the "horns" that have popped up in the car audio scene. Apart from the difficulty of fitting a horn (around 22ft long for the woofer I'm thinking about, should be shorter for a very narrow bandwidth), any problem with using it in such a small space ? Or any sort of other problem…

Hey guys. I used to have a nifty little excel sheet based off of JL's equation, but my computer died and poof went that. Does ANYONE have this document? The original was removed by the poster. Please help me out here guys. That thing was the key to me making any enclosure. Thanks!

From time to time I like to divulge information that helps people understand subwoofer performance. For this particular post I'm going to copy an article from Adire Audio on subwoofer speed. "There's a common misconception out there that heavy woofers must be "slow", and light woofers must be "fast". If a woofer A's moving mass is higher than woofer B's, then woofer A is probably going to be sloppy, or slow and inaccurate. Can't keep up with the bass line. Woofer A simply can't respond as fast as woofer B. There's also this concept that the "acceleration factor" (BL/Mms) is an indicator of woofer speed/transient response. High BL, combined with a low Mms, should give…

so many of you get that you need a pretty big amp for a pretty big woofer, but intuitively this makes little sense right? a big motor should in fact be more efficient! bob explains this pretty well why this is not true... http://www.sunfire.com/pdf/woofwhiteall.pdf

Hey guys, just wondering what your input was about passive radiator boxes used in car set-ups??? I used to have a set-up of 2 12" VMax(the red older surround version) with 2 AE speaker 1050g PR's and its lows were pretty amazing. However, I had to have a pretty large box to utilize them like I did. Are there any advantages to me trying to use these PR's in say a SQ set-up or are there better alternatives out there? Let me know what your thoughts are! thanks

i've been trying to figure this out for a while now.. in a ported enclosure, how would you determine the phase of the sound emanating from the port at any given time? e.g. you have a 4cu.ft box tuned 40Hz.. and you play 3 tones, 35Hz, 40Hz and 45Hz.. will the phase of the port ever be in-phase with the sub? or will the tuning of the box and tone being played determine the phase of sound coming from the port? or would the distance between the back of the woofer and the port determine it?? i know the phase of the sound coming directly off the woofer's cone is 0 deg.. what i want to get is the phase of the sound coming from the port to match that coming from the sub at the d…

I had some kick panels made for my car a few months ago to house my 8" midbass. I had some issues fitting them into the door so I went this route. Even with only a 3/4" spacer, the door panel would not fit back on. Anyhow, the kicks look great, but I think are a bit too small, causing a peak in certain frequency bands. This problem is most noticable with male vocals. I tried filling the kick panels with polyfill...it helped a bit...but did not totally fix the problem. Other than that the system sounds awesome. Staging is fairly high and centered in the driver seat. So I'm opted to try once again to put the midbass back into the doors, and the 3" dome midranges back into …

I'd like to start a topic regarding the technical aspects of sound absorption and how it relates to improving the quality of sound in our vehicles. First, I think we need to hammer out the technicalities of the term "absorption" as there seems to be a ton of misinformation floating around on the forums. What does it really mean to "absorb" sound? How is it accomplished? Second, we should transition from theory to practice and discuss the merits of using this acoustical phenomenon in a vehicle. When should we use sound absorption in our cars? Where should we use it? And perhaps the most valuable question of all: Why should we even try to absorb sound in the first place??…

can someone please explain these concepts of on axis and off axis to me.

Both 12V batteries. but is mixing them going to cause a conflict at all?

Ok I was wondering what is the typical impeadence rise of voice coils? this is why I ask. I have a TC sounds 3000 15 dvc 2 in a 3ft^3 sealed enclosure. I currently am running it in series to get a 4 ohm load on my Phoenix Gold Tantrum 1200.1, This amp is 2 ohm stable. now I have read that at rest most coils are under their rating (please correct me if I am wrong) so does this mean when power is put to them that thay rise to their stated ohm? maybe totally dependent on manufacture? enclosure size? sealed? vented? my main question is is there a better way I should be wiring my sub to my amp? (or is this the best way) if I wired in parallel would I get a 1 ohm load or …

Just looking around and thought this video might be interesting to some.. http://blog.edesignaudio.com/?p=244

ok, see if you can follow me, to create a sonic boom an object has to travel 720mph rite? A driver displaces air to make sound rite, so if I had a sub that would displace air at 720mph could I create a sonic boom in my car? Or would it create an ungodly amount of db's? Also, how loud is a sonic boom? Or is speed and sound not relative to pressure? Or would the sub make no sound at all since it would be traveling faster than the speed of sound or would it just be delayed? would the car explode? just trying to keep those good minds working. lol

I see all these vids of people playing 10 or even 5 hz test tones, and i dont really understand how. If you have it tuned to 35, you set the SS at 30 give or take. Then how is it that the sub can play a 10hz tone. Doesn't the box constrict it, and wouldnt it be unable to control the sub below 30 hz or so if tuned to 35? This may sound noob as hell, i dont care lol. Thanks for reading, Mitch

If i build my wall do i have to deadedn the whole car, or can i just deaden the doors and half the cabin and spray the back half with sealer or specdrum