Printer Friendly Forum Posts - Which direction to point subs?

Hey guys,

I am in the process of making a custom sub enclosure in my trunk for my 2 kicker 10" subs. I will be creating 2 enclosures which I will be mounting in the rear of trunk, sort of like this:

https://web.njit.edu/~cas1383/proj/Glassing2/index.htm

The only difference is that I will be putting 1 sub on each side.

My only question is, does it make a difference which direction I point the subs?

Thanks.

Yeah, if you face them at angles towards each other you will get cancellation...and that is bad. There is a certain point (where the sound waves intersect to be specific) in which sound is virtually in-audible. Basically saying that if you have two speakers playing, at a concert for example, one on each side of you; you can literally walk into a spot and not hear any music at all. What happens is that sound waves are forced away from each other by pressure and the person standing on that line (which is impossible because you are talking about such a thin line) that the worst you would hear is mono. As for subwoofers, the same law of physics apply, it won't be much but if faced at too great of angles you will notice you system sounds a little muffled.

What would be the best way to angle them? Should I point them towards my back seats?

mi_what wrote:

Yeah, if you face them at angles towards each other you will get cancellation...and that is bad. There is a certain point (where the sound waves intersect to be specific) in which sound is virtually in-audible. Basically saying that if you have two speakers playing, at a concert for example, one on each side of you; you can literally walk into a spot and not hear any music at all. What happens is that sound waves are forced away from each other by pressure and the person standing on that line (which is impossible because you are talking about such a thin line) that the worst you would hear is mono. As for subwoofers, the same law of physics apply, it won't be much but if faced at too great of angles you will notice you system sounds a little muffled.

That's a little extreme, but you got the point across.

How far apart will the two subs be, and what frequency will you cross them over at? If it's at 80hz or below and they are 4ft or less apart then very little cancellation will occur.

-------------

Exactly. The wave-lengths below a certain frequency will only be slightly out of phase. Most likely it won't even be audible.

Well, he said they were going to be two boxes across from each other (roughly about three to four feet in a normal size car) and any normal setup should be tuned below 80Hz. I wouldn't go as far to say my view is extreme...it is simple physics and musical acoustics. He merely asked if mounting them a certain way would affect the way they sound and yes it does; will it adversly affect it? the answer is no, it won't. If you read my last sentence in that post it says that it wouldn't be much at all if any...it really only matters if he plans on doing comp.

They will be about 3 feet apart from each other. I did some searching and I found out that if the subs are facing with the magnet pointing towards the back seats that they sound better. Feel free to correct me if I'm wrong.

I snapped some pics of my project tonight so when I get home I will post pictures of what I've done so far.

I myself like the way of the subs pounding away from the inner of the car. They get more bass reflection when it hits the rear of your car's trunk and gives a better effect of sound. I hope you go with the subs driver facing the rear end of the car's trunk. You could always try them both ways and decide on your own preference as well. THats the true test. Waiting for the pics.

-------------
Alpine 7830 HU-4X100 W McIntosh -2X110 W McIntosh-MB Quart Q's Mid Tweets-4X10" Phoenix Gold Subs-Phoenix Gold EQ215ix-AC Epi-PG Line Driver-Phoenix Gold 1 Farad Cap -Clifford Avantguard 4-2 Ear Plugs

for each car it's different i know a guy were it sounds the loudest with the sub at the back of the trunk ponting to the rear of the car

-------------
HU Alpine CDA-9855 Amp MA Audio 802sx 4,400 RMS 1 ohm Sub 18" MA Audio RMS 5,000 @ 1.5 ohm Ported Box Car 99 civic Si

Here is the pic:

https://img.photobucket.com/albums/v632/96LudeSR/sub.jpg

The cone of the sub will be facing the rear of the car.

Let me know what you guys think.

OK.... I sincerely hope that all of you people asking questions on here are also searching the internet for the REAL answers. after reading some of the posts in this thread, im almost ready to loose my dinner. you guys are ALL spitting out information that you heard somewhere else about phase cancellation, time allignment, and bass reflections. seriously, i am ashamed that i even replied to this thread, but as a "live audio technician" and sound re-inforcment desginer, it truly makes me sad to hear such non-sense being written on a site as good as this one. the REAL answer to your question can easily be found on this website, please take the time, and double check your resources.

BTW.... there will hardly be any audible cancellation. so i wouldnt worry about it, and if you think there is some cancellation, scratch the idea and start all over again!!! thats half the fun :)

Okay, I'll ignore the fact that you are an ignorant jackass by assuming all people on here are teenagers throwing together their first system. For a "Live Audio Technician" you sure are in the dark on ALOT of key points when dealing with acoustics. Here I did some research for you:

Click here to learn the real deal about soundwave properties

This will explain EVERYTHING you want to know about how wave travel affects its surroundings.

"Oh and just for your information I am a 98C (Electronic Warfare Signals Intelligence Analyst) in the United States Army...it is MY PROFESSIONAL job to know and understand frequency and wavelength."

Ok guys, lets not get into a "mine is bigger then your's" arguement, because we all kknow I'd win posted_image

LOL

Seriously though. Read this article, it contains REAL measurements of in car bass response with the only variable being the placement/aiming of the sub:
Properly aiming your subwoofer

-------------

That's a great site. I wasn't comparing sizes...merely comparing who's has more experience posted_image

.

No really, I just couldn't believe the audacity of that fellow telling us that we don't know anything because he made a title up for himself.

*Chump* seriously though, the wave cancellation that we are talking about isn't much at all. You wouldn't even be able to notice with the human ear (unless you've been raised around car audio all your life) I was just giving you something to think about when actually doing the aiming.

i was not out to insult poeple, and i definiately did not say that you guys dont know what you are talkin about. im ust tired of hearing mis-applied information being shared on forums. ....not just this one, there are others too. and im not doiubting your experience or anything about you.

sorry if you guys were offended, or insulted, my point was ust to tell you that not all info you hear on here is correct. you all can believe what you want to, but the best kind of information is information, either in a book that is credited, or information you see for your eyes. please, ust take the extra 5 minutes, take some readings and crunch the numbers. the info is there to do it.

I appreciate all of your help guys. I know you all love pics, so here is what my project looks like so far:

posted_image

I have also stretched the fleece over it, but this pic was to give you an idea of how the subs will be pointing.

Looks like you had fun so far. They really don't look angled; did you just decide to face them towards each other? I would sand that resin off of the rings first though. It'll help your subs mount flush on them which will limit air escaping. Looking good so far.

Kinda tough to visualize those in a car or even answer the question w/o knowing what kind of car we're talking about...

Regardless, I don't believe you'll see any noticeable cancellation or propogation based on placement unless you've got a damn good ear & spend time analyzing these sort of things. You will see certain parts of your car rattle more tho, and other spots may be significantly louder outside the vehicle. that's what I'd pay attn to.

I agree that the first answer you got here about the "dead spot" between concert speakers is a little silly. There may be some theoretical value there, but you could do an experiment in your car by putting your ears in the middle of the cabin between the two door speakers. You won't find any real dead spot.

That looks awesome. Click on MY LINK at the bottom and check out the angle I did my sub in. I have one 10 in a glass box and it hits harder than I could ever have imagined.

-------------
Why do you ask if I ate paint chips when I was younger?

mi_what: I agree that they are not angled that much which is sort of what I wanted to do. Regarding what you mentioned about sanding the resin, the sub will be mounted onto the inner mdf ring, the outer mdf ring was just so the sub would be mounted flush and not stick out.

Purple crushed velvet - you goin' to the pimp's & ho's ball?

The bronze paint looks good, creative. If it were me I'd mount the amps to the underside of the rear deck, upside down, or even mounted at 45 deg right-side up. Tricky install tho. good luck.

abovestock: I visited your webpage. Your enclosure looks good. I also like the brake calipers, they look awesome. What kind of paint did you use, and how are they holding up? Is there a particular reason you used an airbrush?

I used standard brake caliper paint that I thinnned down with lacor thinner and loaded into my brush. I opted for the brush because of the glass smooth finish and I could also stretch the material further without getting too thin of a coat. I have no clue how they will hold up yet because I have not installed them. I still need to buy crass drilled slotted rotors to put up with my driving style.

-------------
Why do you ask if I ate paint chips when I was younger?

Purple crushed velvet - you goin' to the pimp's & ho's ball?

The bronze paint looks good, creative. If it were me I'd mount the amps to the underside of the rear deck, upside down, or even mounted at 45 deg right-side up. Tricky install tho. good luck.

Thanks, actually it is no longer in the car. The headliner is getting glassed and having the turbo and fuel controlls mounted in it and then painted. As for the amps that sounds cool. I wanted to mount them upside down to the rear deck and flip them out with a linear actuator. Or something along thoes lines.

-------------
Why do you ask if I ate paint chips when I was younger?

Abovestock: I'm just wondering, what made you decide to glass the headliner?

Question: Do you realize that having a non-absorbtion material as a headliner is going to cause some serious reverb?

-------------