So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Topic: So you want 6x9 speakers in the rear deck? Yeah it'll work fine. (Read 14881 times) previous topic - next topic

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #15 – August 25, 2015, 02:21:10 PM

Quote from: thunderjet302;450816

The new speakers are a huge improvement over stock. I am planning on adding a subwoofer at some point. First I need to do the 3G conversion so I've got enough amps to handle the woofer.

Not necessarily - with my sealed 18" subs at home, playing a sine wave in a 800cuft room, I hit 105dB at 8-Watts per channel at 2-meters (2 channels) according to a Dayton UMM-6 microphone and REW. Infinite baffle would get even louder at 8W. I find 105dB about the upper limit of "comfortable", but loud listening, and it is technically well into ear-damage territory. I normally listen in the 80-90dB range.

At 8W (16W total for two coupled drivers), 15Hz is down to 98dB and 10Hz is down around 95dB. 6Hz drops to 83dB, and 3Hz dips down to just above my current noise floor (loud amp fans that I need to replace) at 67dB. My room's noise floor hovers at 58dB right now with the sub amp running, 32dB with it off. There is a lot of room/cabin gain to be found down low.

Most music, you will need well under 100W (under 10A from the alternator) for anything but peaks. Peaks will pull mostly from the battery, not the alternator. Don't be surprised if power draws are in the 10-30W range at higher volume levels. At 12V, that's 1-3 Amps. 100W will generally sound twice as loud as 10W. 1000W will sound about 4x as loud as 10W. Unless playing <20Hz (generally for movies), one doesn't need more than 100W for subs outside of competition. Rotary woofers work much better for <20Hz reproduction for movies, and take a fraction of the power (but cost a lot more up-front at the moment)

Car cabins are even smaller than a 10x10 room. With a proper install (prevent peaks and nulls, which make sound systems turn into one-note bass wonders - the "boomy" that some like, and most hate) and you don't need much power. Cancellation is your enemy.

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #16 – August 25, 2015, 04:23:12 PM

So basically a 3G alternator upgrade isn't a necessity to run a subwoofer? I'm actually surprised by that.

Any suggestion on a decent powered subwoofer that works well in our cars? The head unit I'm running has RCA outputs for a subwoofer. I'd really like to mount a subwoofer behind the factory trunk insulation so it's not visible when the trunk is opened.

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #17 – August 25, 2015, 06:53:53 PM

Quote from: thunderjet302;450830

So basically a 3G alternator upgrade isn't a necessity to run a subwoofer? I'm actually surprised by that.

Any suggestion on a decent powered subwoofer that works well in our cars? The head unit I'm running has RCA outputs for a subwoofer. I'd really like to mount a subwoofer behind the factory trunk insulation so it's not visible when the trunk is opened.

If you want to keep the cargo room, your options are small (10") sealed subs under the rear deck, or infinite baffle. Ported needs a large box. For a cabinet taking up a small amount of room, a 10" will perform similarly to a 12" - bass needs a large cabinet size and without going larger, a 12" won't help you anymore than a 10". For a "powered" sub that comes as a package with built-in plate amplifier, you'll be very limited in choices. Products like the Infinity Basslink fill the requirement, but they're not remarkably powerful in terms of extension and output. Small sealed cabinets need a lot more power to get to lower frequencies, but you may not need that range - natural music won't play much below 50Hz, ever, with only synthetic sounds dipping down further, pipe organs, or explosions from movie soundtracks.

Back before I had any tools, I installed my subs infinite-baffle by cutting some MDF, mounting subs to them, mounting it all to the cross-braces behind the rear seat, and filling the gaps. It took a jigsaw, drill, and some bolts/washers/nuts. Two 10" subs infinite-baffle had good output down to 20Hz. Amplifier was stuck in the rear seat armrest area, behind the plastic panels. The setup took up next to no room and was very efficient. Sounded great. I still have these subs in the car, but would like to try fitting a couple 15" subs back there instead just for the hell of it. With infinite-baffle, the cabin acts like an oversized subwoofer box, instead of a puny little box tossed into the trunk - nice, smooth response, down into the subsonic ranges (high pass crossover/subsonic filter needed to protect the drivers - most amps come with them).

Just a couple cheap Infinity 1260w or 1262w subwoofer drivers mounted in a sealed, ported, or infinite-baffle install will create plenty of bass. Throw on a cheap, small 300-350W rms amp to power them and you have enough power for every listening, or enough power to make highschoolers think you're pushing 1000W+ into big ported 15's. The 1260 is a well-reviewed sub driver that people go to for value, even when running them in a larger home theater environment. Two of these in a trunk, running 300W shared between the pair (not 300W each, but 300W shared or 150W each), will have output numbers like a single subwoofer running 600W - acoustic coupling makes for more output than what you'd expect for the energy you put in.

A couple plate-amp'd subs like the basslinks would also benefit from running a pair, and acoustic coupling giving you 4x more output for 2 instead of only twice the output. As long as the subs are physically close to one another and not directly cancelling each other out , frequencies with longer sound waves will be acoustically coupled.

http://www.masejoer.com/Images/Thunderbird/ibsubs1.jpg
http://www.masejoer.com/Images/Thunderbird/ibsubs2.jpg

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #18 – August 25, 2015, 07:39:46 PM

Quote from: thunderjet302;450830

So basically a 3G alternator upgrade isn't a necessity to run a subwoofer? I'm actually surprised by that.

Any suggestion on a decent powered subwoofer that works well in our cars? The head unit I'm running has RCA outputs for a subwoofer. I'd really like to mount a subwoofer behind the factory trunk insulation so it's not visible when the trunk is opened.

If you want to keep the cargo room, your options are small (10" sealed subs) under the rear deck, or infinite baffle. For something taking up a small amount of room, a 10" will perform similarly to a 12" - bass needs a large cabinet size and without going larger, a 12" won't help you anymore than a 10". For a "powered" sub that comes as a package with built-in plate amplifier, you'll be very limited in choices. Products like the Infinity Basslink fill the requirement, but they're not remarkably powerful in terms of extension and output.

Back before I had any tools, I installed my subs infinite-baffle by cutting some MDF, mounting subs to them, mounting to the cross-braces behind the rear seat, and filling the gaps. It took a jigsaw, drill, and some bolts. Two 10" subs infinite-baffle had decent volume down to 20Hz. Amplifier was stuck in the rear seat armrest area, behind the plastic panels. Took up next to no room and was very efficient. Sounded great. I still have these subs in the car, but would like to try fitting a couple 15" subs back there instead just for the hell of it. With infinite-baffle, the cabin acts like an oversized subwoofer box, instead of a puny little box tossed into the trunk - nice, smooth response, down into the subsonic ranges (high pass crossover/subsonic filter needed to protect the drivers - most amps come with them).

Just a couple cheap Infinity 1260w or 1262w subwoofer drivers mounted in a sealed, ported, or infinite-baffle install will create plenty of bass. Throw on a cheap, small 300-350W rms amp to power them and you have enough power for every listening, or enough power to make highschoolers think you're pushing 1000W+ into big ported 15's. The 1260 is a well-reviewed sub driver that people go to for value, even when running them in a larger home theater environment. Two of these in a trunk, running 300W shared between the pair (not 300W each, but 300W shared or 150W each), will have output numbers like a single subwoofer running 600W - acoustic coupling makes for more output than what you'd expect for the energy you put in.

A couple plate-amp'd subs like the basslinks would also benefit from running a pair, and acoustic coupling giving you 4x more output for 2 instead of only twice the output. As long as the subs are physically close to one another and not directly cancelling each other out , frequencies with longer sound waves will be acoustically coupled.

Infinite Baffle Subs Front
Infinite Baffle Subs Rear

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #19 – August 25, 2015, 11:30:38 PM

Just found a parts Mark VII in my area. I'll be doing this soon (my back speakers have been blown for a while now)

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #20 – August 26, 2015, 03:26:25 PM

I've been thinking of adding this particular woofer: http://www.amazon.com/Infinity-Basslink-200-Watt-10-Inch-Subwoofer/dp/B000063TJY

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #21 – August 27, 2015, 01:41:47 PM

Quote from: thunderjet302;450847

I've been thinking of adding this particular woofer: http://www.amazon.com/Infinity-Basslink-200-Watt-10-Inch-Subwoofer/dp/B000063TJY

They'll improve the midbass, but thrown into the trunk, it may sound boomy. Better than no sub, and if you EQ it right, the sub should blend in fine. If you can put a 24db/octave 63Hz high pass crossover on the 6x9's from a headunit, you should be able to prevent them from bottoming out. If 12db highpass, I'd set the 6x9's at 120Hz. I have no idea what protection the speakers may have built-in - they could have a capacitor already.

Stock stereo, you can build your own passive crossover. http://www.the12volt.com/caraudio/crosscalc.asp . If you want the simplest filter with one capacitor per speaker, you'd probably want a 1st-order (3db/octave) crossover. With your speakers, 200uF would be down 3dB at 200Hz, 6dB at 100Hz, and 12dB at 50Hz.

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #22 – August 28, 2015, 11:58:35 AM

I may give it a whirl and see what happens. Right now the system is the stock EQ and amp with a JVC headunit (wired in with RCA preouts so it works like the stock radio) wired in place of the stock head unit and the Polk speakers.

So you want 6x9 speakers in the rear deck? Yeah it'll work fine.

Reply #23 – August 28, 2015, 02:18:32 PM

Quote from: thunderjet302;450903

I may give it a whirl and see what happens. Right now the system is the stock EQ and amp with a JVC headunit (wired in with RCA preouts so it works like the stock radio) wired in place of the stock head unit and the Polk speakers.

Ah, yeah give it a try. You may be EQ-limited in your setup. Two of those subs would give you far deeper extension, but you would probably need to pull back the 50-125hz range by almost 10dB, if you want to get rid of boominess. With one sub, you should only need to pull 3dB from the 63-125hz range. If you like strong midbass, then just wire it in and go!

EQing can help bass a lot, even with poor subwoofer placement: