you need 3-way's up front to bring the details from the subwoofer out again.
it doesnt matter if you've got a hatchback or an SUV or if the soundwave goes through the backseat .. they all have muffled bass because of the soundwaves bouncing off the walls and seats and windows.
you also need new cones for the front because there isnt any dust cap.
you cant expect the cone to push on the air with a hole in the middle.. all of the air will escape down the pole holding the tweeter out the magnet in the back.
if i had the money to do it myself..
i would get a 3-way crossover, a woofer that will fit into the hole that says it can play down to 30hz .. up to whatever the crossover frequency is (or higher) .. then try mounting a dome midrange and a dome tweeter anywhere under the speaker grill.
(even if that means getting some wood and putting some holes through the wood that the screw for the speaker can go through and keep it connected to the speaker .. and i would start with cardboard first because it is readily available and see if that is the best spot for the midrange and tweeter or if it sounds better somewhere else .. but if you are using distance delays, you will want to keep them all in the same place)
there isnt anything better to compliment the bass other than helping the bass with the details being heard.
it is like going from a junk muddy subwoofer to an audiophile subwoofer with lots of details and clarity (you know the ones where people hear it and say that type of clarity is hard to find)
you are running into a problem real quick without seeing it ...
if you get a four channel amplifier for those speakers, the only way to connect the subwoofer to it is to bridge the subwoofer on one side of the amplifier between right and left .. and it really helps to note if the amplifier says it can do that because otherwise the amplifier might go into protect mode or simply die much sooner than usual.
so what is the problem?
well 40 watts per channel is probably only going to be 80 watts for the subwoofer.
if you do both sides of the amplifier for a dual coil sub, that is only 80 watts per coil.
it really isnt much power .. satisfaction usually doesnt happen until about 150 watts , unless you find some generic subwoofer with a really high sensitivity that will output the decibels with the lower power.
and i dont think this is an option that should be ruled out.. because some of the generic subwoofers sound much better than the more expensive 'warehouse' list of subwoofers (alpine, rockford fosgate, kicker, kenwood, pioneer, etc).
no, they dont have audiophile quality.. but sometimes they sound better than one of the above brand names and people just laugh into hysteria because of the money they saved.
the trick is to get some more details out of the subwoofer by using the bass from the front speakers.
the audio industry is asking you to do it right, instead of dropping speakers into the holes and pressing play expecting it all to sound better.
(it sounds different, and usually it is louder.. but audio engineers design the stock systems and they usually sound better if they arent turned up to the point of distortion .. but they always leave room for more loud, sometimes it prevents babies from going hard of hearing because their parents were listening to music in the car too loud .. sometimes it is to help all those after-market audio companies)
they are trying to help..
that is why some of the decent subwoofers are generic brand name and they sound better .. because they want you to save money and see if you will use that extra money to make the system even better.
the first place to look at is what do they do after they throw in a subwoofer?
sure, some of those generic subwoofers die easily when they are running at the RMS level .. but for the person that ran the amp lower than RMS .. they go the distance where brains and wanting it bad enough overpowers the next person with too much money and not enough brains to HELP it all happen .. because they think all of that extra money should help make the whole thing sound perfect .. when in reality, it goes towards making the products last longer through cold or lots of exposure to sun or throwing too many watts at it or running the output to distortion for a long time.
(they pay to care less and continue playing .. compared to the other half of the equation that cares more)
there is a lot of people in this world that knows somebody that would be willing to turn up the volume knob until something starts to distort, and then just leave it there because they are obnoxious enough to want it loud and loud only .. not because they want the speaker to last without needing to be replaced.
i like to think those people are careless fools just itching and scratching to literally pay lots of money to learn from their mistakes .. and maybe one day when they are old and wrinkled they will think back about all the money they wasted and wont make those mistakes anymore .. and maybe they teach other people not to make those same mistakes.
so you are going to need a 5 channel amplifier..?
most likely yes, that is the answer.. because one 12 inch subwoofer needs more than 80 watts to really make an impact.
i've got four speakers running on 15 watts each .. and two twelves running on 150 watts total .. and those subwoofers still dont have enough power to tightly control the cone with enough force to bring out the clarity.
but that is because the voice coils want 600 watts and i'm only feeding it 150.
the gap is really large between 600 and 150 so i cant expect the subwoofers to make solid use from the 150.
i made it happen anyways with time alignment and spatial imaging .. but i'm still needing more watts to get the cones to move and get the details out of the cones .. because each cone is only getting 75 watts.
again.. 300 and 75 is a really big gap.
it does happen, but it is like listening with the volume too low to hear.
i am satisfied somewhat because i didnt have any bass at all in the car before.
and for the $50 for the amp and subwoofer that was given to me .. it was worth it to get them in.
(thinking i could go up from 150 to 250 and probably be happy)
there are a bunch of 5 channel amplifiers.
some of them have 120 or 150 watts per channel.
here are some dome midranges that you could screw into a piece of cardboard or however you want to get it setup next to the midbass:
maybe you can might need to sand the speaker hole a little bit bigger for these:
i dont know how good those sound because i havent heard them .. but they are an example for the principle.
the woofer 'wants to move' at about 30hz .. and that is good for helping bring up the details down to 30hz (maybe less because of the speaker box size inside the door .. but still a valid 'loose' frequency)
the crossover point between woofer and midrange should be 1,000hz .. the other crossover point between 5khz - 7khz
the woofer is 50watts 4 ohms
the midrange is 80 watts 5 ohms
that means you could stay with the same 40 watt speakers in the back and run it off the same amplifier.
if you dont care and just want amplifier suggestions (maybe somebody else will) ..
i seen one from boss, one from power acoustik, one from kenwood
price range was anywhere from $150 - $250
some of them had higher distortion numbers than others.
some of them had higher power values than others.
some of them had a class A/B amplifier for the 4 channel .. and a seperate class D for the subwoofer (the other ones were all class A/B)
some of them had higher signal to noise ratio's than other ones.
simply put ..
if your radio doesnt put out much for voltage from the RCA outputs then you dont want an amplifier with low signal to noise ratio because you wont be amplifying much of the details loudly without a line driver that boosts the RCA voltage.
my amp has a signal to noise ratio in the 70's and when i turn down the subwoofer level, the details disappear.
that tells me the details are getting lost in the lower voltage from the RCA output and the amplifier isnt helping any.
dont waste your time with high distortion amplifiers .. they will be loud, but the details arent any better .. it doesnt matter if you are listening to electronica or classical because the details will be missing/distorted in both.
you should be able to get lots of extra oomph from those front 6.5 inch speakers playing bass.
i had two 6.5 inch speakers in bass reflex boxes in the trunk of my moms car and it would shake the rear view mirror .. and they were at 55 watts each (the woofers are about 100 watts RMS).
it is really beautiful to hear the large bass filling up the vehicle from a subwoofer with some enveloping bass fill from the front speakers.
i just cant emphasize it enough about the extra details heard.
if i had to give a comparison .. it would probably be this..
imagine you are in the bathroom taking a shower or bath in the tub .. and you've got the music blasting in the other room to hear it in the bathroom.
that is like bass coming from the trunk.
then you wire up a speaker with a cord going all the way to the amplifier and you set the speaker inside the bathroom.
that is like listening to the bass from the front speakers.
the space inside the vehicle is small and tight .. those little 6.5 inch cones arent going to fill up the tight space with enough satisfaction compared to a subwoofer added.
the easiest way to put it is this..
the space in the vehicle is tight like a spring that doesnt want to move.
those little 6.5 inch woofers are only going to make that tight spring move so much.
that is why you get the bigger cone from a 12 inch woofer to help (and that is why people buy two 10's or two 12's for more bass) because the bigger cone will force the tight spring to move.
it is the movement of the tight spring that you hear as audio .. and if there is some pressure with the audio, it can make listening more fun too because it is like the audio has more 3D depth.
this boss amplifier has really good specifications on paper .. and 13 people gave it good reviews (one person said the amp broke after a year, but they didnt say what they were doing with the amp)
there is more power than you need for the speakers.
and that means running 60hz through the amplifier with a multimeter to set the voltage to the number of watts you need (so you dont burn up the voice coil)
instructions for that is here:
200 watts for one 12 is enough to get the tight spring moving .. but maybe one twelve isnt enough.
it really helps if you got a speaker box that is designed to help you instead of set at the same standard 30hz - 40hz boosted tune.
(it should be 20hz - 30hz)
you dont want loud and muddy.
it is better to be less loud and more clear.
i havent heard a large list of subwoofers to tell you exactly what to get.
this subwoofer is getting really good reviews:
i've owned some peerless midranges and i thought they were 'ahead of their time' because they sounded really good.
might as well say they are from a toy chest labled 'audiophile' .. because they were absolutely an improvement over anything i heard in the stores.
the reviewer said the box was tuned for 18hz .. the same as the FS specification.
that that much of a loose wiggle, there should be enough details inbetween to satisfy.
....and for what it is worth,
nobody knows what the speaker sounds like until they've heard it themselves or had an accurate detailed description from somebody that has heard it.
only thing else is the name brand on the speaker and if you've ever heard something else that they've made.. and then assume the quality cant go down too much without ruining the reputation.
the bad thing about mixing bass from rear speakers with the subwoofer ...
well there is the phase difference, that is always one thing.
but then there is also the timing from the speaker .. when they are different, you can clearly here there is the same bass coming from two different speakers.
it is annoying and it is all supposed to blend together.
you could still use the sony's and set the crossover to stop sending bass to the speaker, and that will stop the problem dead in its tracks.
classical is easier to work with without an equalizer than electronica music.. because electronica music demands a flat frequency response more than classical.
funny though, because once the frequency response has been made flat, the classical music will gladly take advantage of it.
but electronica music just doesnt have the same energy when the frequency response has dips and peaks.
sad for some people..
because one person thinks audio is a toy, another person thinks audio is serious.
but even the serious one will get out a calibrated microphone and fix some problems .. and still see the results (although a huge improvement) are still somewhere between toy .. teenager .. and 20 year old.
and if you think throwing in some after-market speakers and amplifiers to make it all louder and sound different than the stock radio is 20 year old (not teenager or toy) .. then you will certainly feel like 60 or 70 years old with the calibrated system.
it is like rolling around with a fresh new college degree that makes you better than thousands of other people .. AND you know you've still got 40-60 years to go back and get another one or two or three.