I have it firing out towards the rear, but would it sound better if i turned it the other way and have it pointing towards the front of the car? Of course I would have to change the phase by swapping the negative and positive of the speaker wire that goes into the sub.

Would this make a big difference or no?

 

Go on an actual car audio forum and search for 'cancellation'. Forward firing is best only in IB/TB applications. Even hatchback platforms are best suited for rear firing; some guys will try up-firing, but won't see much of a difference in output.

Sedan/coupe: rear firing, positioning the sub(s) closest to rear seats as possible.

Venting points (rear deck, ski trap in a sedan; rear seat down in a coupe) are crucial.

 

I have experimented with all 3. Rear firing in the coupe was best, but I had to go with up firing my 2 12"s due to space requirements. It sounds fine to me, still hits and maintains a relatively good level of SQ, at least to my ears and people that hear my system. I removed the rear 6x9"s so they fire up right through the Bose grills (sound damping the rear deck is a must in this application by the way). In the near future I will be making a stealthy trunk box / amp rack and have them rear firing, the way to me it sounded best without getting into all the physics explanations as to why.

 

If you rear fire them you it bounces off the trunk and the rest of the walls within the trunk which will also give the subs a little air space prior the sound getting to your ear. Which sounds better personally. If you fire them straight into the cabin than the subs don't have anything to bounce off of prior to you hearing them and they also don't have the air space needed to move through. In an open car like a hatchback or SUV it doesn't matter because one way or another the subs are using the same space because it is an open vehicle. If you want to eliminate this problem you can get a ported box and you will Notice a HUGE difference in sound.

 

^ What he said. I more or less fall into the open space SUV/Hatchback category as there is very little seperation between my trunk and cabin due to the removal of the 6x9"s. So pretty much there are 2 gaping holes between my cab and trunk. Not quite open air, but not closed off either.

 

for me i had my 2 subs fire on angles facing slightly forward and upward

this i found was the best to feel it withing the car

IMG_0534.jpg?t=1270493998

 

...which is good or bad? If it's an actual sub enclosure placed in the trunk & facing forward, then it'll sound muddy by default because of cancellation created by the rear seats. You'll lose output and SQ. If it's an IB through the factory sub opening (sedan) or dual IB through the 6X9 holes (coupe), it's the best scenario with respect to efficiency. That is, if you own sub(s) who can perform well in an IB environment. Otherwise, if it's a trunk baffle setup through the ski trap (sedan) or through a trunk wall (coupe) using an enclosure that's completely sealed off of the rear seat (sedan) or its opening (coupe), you'll get IB-like output and traditional enclosure driver efficiency. An option you consider when using subs that are not IB-friendly, and that's a boatload of them.

To a certain extent, you can consider an SUV or big hatchback car as a HT room. One of the guiding principles in home audio for sub bass response & overall clarity (eliminating any possible cancellation issues) is corner loading - which the guy who posted a pic of his trunk did. May sound good, may not. There are waaaay more variables to consider in the sub placement thinking process when your environment is an actual trunk. Your car resonating frequency (res freq), the design of your trunk & rear seat and the position of your cabin venting points within the trunk area all have to be factored in your decision.

Essentially, it does matter. You'll hear an audible difference switching between the rear/down/front/up/corner firing setups for a given sub(s) & amp combo.

Yep, by going ported you're inducing a peak in your transient response around the tuning frequency. Gain in output, but your freq response curve is now very far from being flat - not ideal for SQ, unless you have the right driver to tune your enclosure around 28-30 Hz so that this peak is found in the lower lows, allowing a certain smoothness in output after ~45 Hz provided your don't cross the sub(s) too high @ amp.

Why would going ported eliminate the speaker placement problem? Sound will be different in a lot of aspects, but a traditional front firing ported setup will sound like total **** regardless of the trunk or ski-trap being open or not.

Corner loading. So how did you carry out your preliminary testing?

Did you have those subs placed all over the place, at all angles to come to the conclusion that corner loading was the best course of action to take?

Did you record cabin gain & overall output using an RTA?

What are those exact subs you're using?

Nice Audison amp. LRx series, isn't it?

 

^ Personally depending on the ported box will change the placement of the sub. I have had two different ported boxes. One box only sounded good when fired to the rear the other box sound good no matter how you placed it. The second box I had custom built for the sub and the car so that has a lot to do with it.

 

i had the company that was installing it place is in the most common places, facing front, facing rear, and facing up, however i suggested using custom fiber glass enclosures molded to the sides fast angled like i have it now(saw this on a nissan sentra 4 door, was pretty good quality sound) so we gave it a try and got lucky, it sounds very good, the great thing about it was that you hear it very loud inside the car but not so much outside like most setups which is what i did not like, of course it also depends on the set up you have, how much bass you are putting out without baffling the treble, yes that is the audison amp lrx 4 channel for the 4 focal speakers, and a 2 channel audison amp behind the spare tire under where the 4 channel amp lays and an alpine double din screen, the subs themselves are jl w3's 10inch, i went with 10 for more crisp clear quality yet hit all levels of bass, i am very happy with the positioning of the subs, unfortunately i did not take any recordings, just simply using the sound of ones ear

this was all 3 years ago, i paid a fortune for the parts and labor, all the parts were brand new on the market, now they are dirt cheap and to this day it still pounds as loud as it ever did

 

Assuming the sub used in both applications was the same, what model was it?

Slot, aero or flared ports on the two boxes? Tuning frequency? Net volume?

That whole para is a lot of wind if you don't mention any enclosure specs.

...and so, did they use an RTA? What's the point in trying all this if you can't record what your freq response is like?!? That's not much of a preliminary test if you don't strive to find your car res freq.

Not true. It depends on the extent of your sound dampening install. Rattles and air leaks from the body are car dependent; with the same car, you fix all this using sound dampening material (SecondSkin/Raamat/CLD tiles/eDead/Hushmat or Dynamat if you're a mainstream boy), not a different setup.

...I'm sorry, what? Are you saying that "too much bass" will affect the treble portion of your freq range? I wonder how that's possible when your tweets are up front with the sub(s) in the trunk. Lows will cancel other lows in applications prone to cancellation, but lows will never cancel highs. Holy hell.

What are your amps crossed at? What slope? Any x-over setting @ HU?

You can't "baffle" the highs with lows. If your x-over settings don't call for an insane overlap between your subs & mids, no portion of the freq range whatsoever will get "baffled" by bass.

4 Focal speakers? Please tell me you didn't just put 2 pairs of Focal coaxials in that car, hooked up to an LRx amp.

How do you have it setup, are you bridging the amp for your front stage or are you running all 4 different channels and throwing all staging + imaging considerations out the window? What's the component set model up front?

Again, not true. I could make an Adire Brahma15 sound "more crisp, more clear, and hit all levels of bass" than your mid-line W3s.

Transient response is dependent on driver efficiency, suspension + spider design, thermal AND mechanical power handling VS enclosure & amp, the DF of your amp, etc etc etc.

That statement you just made confirms that the "My 10's will sound tighter than your 12's just cause they're 10's" popular misconception is still out there. Saddens me, but at the same time.. this is an actual performance forum, not a mecca for car audio enthusiasts.

 

^ok, most of what you said i have no idea what they are haha, as for the whole 10vs12 i apologize for that, as for the 4 channel with 4 speakers, its 4 speakers with 4 tweeters, 2 of the speakers are at the far rear with tweeters hidden and 2 speakers are at the far front with the tweeters up far most where the door is above the dash, 1 channel for each speaker i guess, as for which model of focal speakers are they, i really do not remember, if it helps they are the ones with the black cone, not the yellow ones(high end model) or the one with the silver middle, all i know is that it sounds amazing, better then what i had expected when running 4 speakers compared to stock 6 speakers, i have a few friends with G's and Z's and custom subs and speakers, most run stock speakers and head unit, i still prefer mine, there's is just about pumping the bass up as loud as possible so everyone can hear it


all i know is i love it, except for my rear view mirror vibrating haha

 

What does that Audison put out @ 4 ohm? 4 X 50, 60w rms? Which one of the two Audison LRx 4-chan's is it?

Sounds like you a have component sets up front and.. at the back. But why? A better set up front to accept the most out of that amp would have been even more 'amazing' in all SQ aspects. Especially if your Alpine HU has time alignment. Music is recorded in stereo... you're not supposed to hear instruments or voice coming from the back, unless you turn your back to artists at concerts.

Polyglass or Access? Pretty big difference between the two.

http://www.woofersetc.com/p1165/165V...-Component.htm

http://www.woofersetc.com/p3372/165A...t-Speakers.htm - silver middle?

K2Ps, I'm assuming. Polykevlar series.

http://www.woofersetc.com/p3411/165K...Components.htm

http://carphotos.cardomain.com/ride_...0011_large.jpg

http://carphotos.cardomain.com/ride_...0014_large.jpg

http://carphotos.cardomain.com/ride_...0049_large.jpg

http://carphotos.cardomain.com/ride_...0012_large.jpg

And that's all that matters. If it sounds great to you, all the better. I'm still convinced that you'd be wowed by a nicely tuned front stage, SQ oriented component set with (silk/alum/titanium tweets, whatever your ear likes most) powered by your Audison amp - super clean btw, but I'm not sure you know exactly why in terms of specs lol.

A stock head unit feeding low quality processing, all-around dirty signal to a high current design class-D amplifier that's used to drive power-hungry subs is a strange idea. That dirty signal gets boosted up insanely before reaching the sub's voice coils, hence the wet -but extremely loud- farts you hear coming from their setup. High amount of unwanted noise in the signal (think of many, many dents in the sine waves the voice coil has to reproduce) would be the cause of it. Would sound even worse if in a large ported, tight on power application.

You didn't let your system's weakest link be the HU.

 

helpful info., thanks yall

 

Rear facing is generally the most desired setup, but I went with the corner facing angled in simply to save space. Our trunks are so small that saving any space I could was more important to me than the small difference in sound.

 

biggz, you do that yourself? that setup looks super clean.