I've been spending a lot of time trying to figure out what to do for a sub for my fiero. Currently I have the factory box with the tang band sub. It worked well for a while but I ended up blowing up the sub. I did like that setup and definitely suggest it, easy and cheap, I was happy with it. But it was lacking a little bit. It is only a 5 1/4 sub after all, you can only expect so much from it.

First I have to say I have no interest in discussing anything to with subs in the glove box/center console. I also don't want to cut into the rear firewall. I have read up a lot on it and I am aware that in reality it is the cleanest looking and has best outcome. But I just don't feel like cutting into the car and making the large modifications to perfectly good interior pieces. Maybe one day I'll get into it but not now.

The only options I am interested in discussing are under dash sub or behind the seat without cutting.

I had "decided" that I would put a 10 or 12 behind the passenger seat. So I built a cardboard model and put it behind the seat to see how exceptable it would be as far as loss of leg room and looks. The biggest box I am willing to make has a volume of 0.594 cu.ft.. That is with 3/4 MDF but not taking into account sub displacement and bracing.

One thing I had learned that you need to find a sub to fix the box volume. Not the other way around. So with 0.594 cu.ft. that ruled out 12" subs, they need way more space.

Couple things I should mention. I am by no means educated in car audio or audio in general. I've just started to learn to make an educated decision on what I should buy and how to get the sound I want. That being said I'm only going to be talking about sealed enclosures. One reason is because they are less complicated. Secondly because from what I have found vented enclosures need more airspace then any location I'm interested in putting a sub

One other thing I need to mention is any sub that can be considered for behind the seat needs to be a shallow mount.

So I looked into 10" subs. From reading and asking around on car audio forums, the kenwood was suggested. It has a suggested sealed box of 0.6 cu.ft. I thought that I was/could get close enough to that to get it to work. I kind of assumed a sub should be 10" or bigger to be able to function well as a sub (get low tones). From what I can tell I was completely wrong. The other thing I came to realize was that if you try to stuff a sub into a box that is too small for it then it will just sound like crap.

So this brings me to 8". They require less volume so are more suited to the application that I'm trying to put them in.

I'll list the prospective subs in a minute.

Now the next part to add to the confusion. How do I know what is the sub I should buy? Well I was directed to plug each sub's T/S parameters into a Qtc Calculator, here. Ok so now that I've done that I get a Qtc # and a Fc #. What does those numbers mean. Truthfully I have no idea. This is all info I found on what the Qtc # means, Fc doesn't seem as important.


Before we get to that, instead of using the above calculator, there is a program called winISD. It is very helpful in finding the optimal box size for a given sub. It can also do a lot more but I'm not well versed in on it. Guide I followed here.

quote Originally posted by Blacktree:It depends on how you want the speaker to sound. When designing an enclosure, the first thing to do is determine what Q factor you want. The Q factor determines overall sound quality. The lower the number, the deeper and tighter the bass will be. The higher the number, the more "punchy" the bass will be. A bigger box will yield a lower Q factor, and vice versa. Here are some sample Q factors: -- 0.9 : general automotive use (very boomy, and weak in the lower frequencies) -- 0.8 : "high-end" automotive use (not as boomy, and a little richer than the above) -- 0.7 : all-around home theater and music (not very boomy, pretty tight, and pretty rich) -- 0.6 : audiophile quality (very tight and rich) If the Q goes above 0.9, the bass will sound boomy and distorted. And if it goes below 0.6, the bass will sound flat and "dry". Since space is usually at a premium in an automobile, speakers are usually put in high-Q enclosures, with electronic gadgetry (equalization, bass boost, etc) to correct the sound quality. So for an automotive speaker, stuffing the enclosure and/or using a slightly larger one will definately improve sound quality. It will also reduce (possibly even negate) the need for bass boost and/or equalization to get the desired frequency response. You should still use a crossover, though. Crossovers are critical to sound quality, no matter what size/style enclosure you use.

quote Posted on diymobileaudio.com:You input the drivers Vas, Qts and Fs then it will tell you the size of a sealed enclosure for a .707 Qtc alignment, which is considered by some to be ideal. You can also put in the size of the enclosure and it will tell you what the Qtc would be. You want the Qtc to be below 1.0 and probably even below .9. Somewhere between .7-.8 should give you decent low end. It will also simulate the enclosures response on a graph. The drivers Vas and Qts are what typically define the size of enclosure the speaker will work in. The higher the Vas, and or Qts, the larger the enclosure it will need.

quote Posted in a guide on the12volt.com: The value of .707 is what you are looking for here and you want to get as close to it as possible

The last two quote's are referring to using winISD. I also may have forgot to mention that I'm going for SQ (sound quality) not SPL (sound pleasure level). So at first after reading blacktree's post and a few other before it I should be aiming for a Qtc of 0.8. But it also looks like the "0.707" is the best Qtc for SQ?

So as to what the best Qtc value is, how much it can vary off of the best value and anything else to do with it, I'm lost.

Now on top of that, I have put all of the subs into winISD and it has provided some good info. Very little of it I actually understand but it does point some things out. So I have this graph that I don't really understand (posted bellow). To me it doesn't look like there is a big enough difference between the subs to actually sound any different. When I say this I mean on paper because from what I have read subs sounds different in person then on paper. What I also had read that difference of 3db or less isn't noticeable.


So the two locations I have/will consider are behind the seat, or under the dash.

Subs suitable for behind the seats, can also be used under dash, all box sizes are based on a Qtc of ~0.707
8" Dayton S210 - 200RMS - 0.211
10" ED SQ10 - 250RMS - 0.341
8" Kenwood -150RMS - 0.5

Subs suitable for under the dash, all box sizes are based on a Qtc of ~0.707
8" JBL GTO 804 - 200RMS - 0.338
8" Dayton DCS205 - 150RMS - 0.33
8" TB W8-740P - 150RMS - 0.178
8" TB W8-1363SB-120RMS - 0.134

8" TB W8-1747A-350RMS - 0.415 - 0.28 (Qtc of 0.8)
8" ED 33.8 - 200RMS - 0.26 (Qtc of 0.8)

8" TC Sounds Epic 8" - 300RMS - 0.095 <-------------- This sub looks like it would be perfect for the fiero, it need NO volume. Very heavy though. (22.9mm Xmax!)

(All other subs either required too much volume or too long mounting depth)


My picks based on the little I know. Behind the seats Dayton or ED. Under dash the JBL looks good but the TC looks bad ass. But the JBL is ~ $65 and the TC is ~ $140.


As far as boxes go. I've see the "tube" that was made by a couple people on here for a 8" under dash. Could not find the volume of it though. Only other indication I could find for how much volume is under the dash is a post made by mister, with his dimensions and assuming he used 1/2in MDF, there is 0.202 cu.ft. of volume in a square box under the dash in a non A/C car. Mine also doesn't have A/C so I am curious to know if anyone has utilized the extra space other then mister.

quote Posted by Mister: #1 stealth 8" - under the dash 11*8*6 inch (No AC unit) (grille installed later)

Comparison of subs in winISD, all ~ 0.707 Qtc


SPL of same subs


Comparison of JBL @ 0.707 Qtc and more realistic box size for under dash, 0.2 cu.ft. Qtc of 0.826

I am using a Rockford Fosgate 8" in a custom built subbox that is .220cf under the dash.
The reason I made my own box (out of 1/2 MDF) is because I shaped it so the angle was on the face. This allows a little bit more room for passengers feet.
You can see pics here:
http://www.polkaudio.com/ca...talls/view.php?id=13

In order to pick a sub you actually need to listen to a few brands first. Many have different sound characteristics. Once you find a brand that you like their sound, Find one that suits your design. Just because the numbers look good, does not always mean the sound is something you like. Find one with decent numbers and decent sound and you will be very happy.

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Happiness isn't around the corner...
Happiness IS the corner.
ZZ4 Powered !!

I was actually referring to the blue under dash sub in the above picture. I don't want anything in the footwell. I want it to be stealth.

Nice set up you have though.

Unfortunately I don't have the ability to listen to any of these subs first hand. Hell I can't even get guys on a local car audio forum to comment on any of them. I would love to be able to get a few different ones and try them in different enclosures and see how they sound. But I can't afford to buy a bunch of speakers that I don't need. So I have to rely on numbers and any experience others have had.

I also don't know a lot about car audio, I been learning as I go. So for example, I don't see why anyone would go through the trouble of building a large box if the TC sounds sub can (on paper) sound good in a 0.095 cu.ft. enclosure?

I'm hoping to find a good combination I can recommend to others so everyone can benefit.

[This message has been edited by bnevets27 (edited 04-28-2011).]

I built a sub enclosure using 8" sonotube capped with 3/4" MDF. It fit perfectly in that same space you identified. Length was roughly 12" and volume was 0.33cuft - perfect for the Polk Momo sub. I hung it from an existing bracket and braced it to the kick plate - so no holes were drilled in my car to complete this install, and nothing is visible from the passenger compartment.

dave

Dave....
Hey man pics or it didn't happen!! haha peace

Pete

Have you considered using a flat subwoofer for behind the seats, you can get some as thin as 3" up to 1500 watts with very good sound quality?

Thanks for the info dave. This is exactly what I have been thinking about, just yesterday actually. I have some 8" sonotube around here some were I was going to try out but I can't find it. I guesstimated I could fit about 10" in length, that was basically by eye.

Just to double check your volume I used a calculator. A 8x12 tube with a wall thickness of 0.1 = 0.3263 cu.ft. Sounds good. Did you reenforce the tube though? I would worry that it would flex a lot. Not a big deal but wondering your experience with it. Wouldn't be a big deal to lay a few layers of fiberglass over it. I would love to see some pictures. Wouldn't mind listening to it ether if I could at some point.

Blue by u, yeah definitely considered it. Built a cardboard box and even bought a slim sub. It was what I was planing to do. But it didn't seem ideal. There were quite a few compromises I had to make that I didn't like.

The cardboard box I made was 19.5H x 29W x D. Fit the angles of the back wall. Physically the thinnest 8" sub I could find has a mounting depth of 2.5" and isn't vented in the back do it can be flat against the back of the box. So with the dimensions above, and a depth of 2.5", using 3/4 MDF , accounting for some bracing and sub displacement I get a volume of 0.017 cu.ft. Which is way too small for any sub to function properly. So the smallest dimensions I can use and still have an acceptable volume in 19.5H x 29W x 3.21D. That gives me a box volume of 0.222 cu.ft, that includes accounting for some bracing and sub displacement. Thats good enough for a couple subs so that would work fine. Just for completeness of info. Same box with a depth of 4.5 (19.5H x 29W x 4.5D) has a volume of 0.564 cu.ft.

The compromises and challenges I was speaking of earlier are as such. Loss of some leg room, though the amount of leg room lost I think is acceptable, there is a lot of leg room on the passenger side of the fiero to begin with. Large heavy box, not sure the weight it would be but it would be a lot of thick MDF (3/4). Not the simplest of boxes to build because of the angled back wall of the fiero and I wanted to match the top angle of the back wall also, to look nice. It would have to be carpeted also, to look good. The selection of subs is somewhat limited. It's not too much of an issue as there are a lot of slim mount subs out there. But a lot of them still need a good amount of air space. Can't really use any larger then a 8" because of the required volume. Only one 10" I found would work ok in that amount of air space.

From what I could find, the 8" subs that have full mounting depth are better subs. There are a few more choices for subs also if your not limited to shallow subs. Also if I can't really use any bigger then a 8" behind the seat and I can fit a 8" under the dash, there's not any real advantage to a box behind the seat.

I knew I had seen a box sculpted to use all the available available space under the dash. Couldn't find it for a while but finally found it last night: https://www.fiero.nl/forum/F...ML/048207-2.html#p65

Estimated volume = 0.33 cu.ft (+?)


Too bad they aren't being produced yet. One small modification I would like, but I'm sure I'm in the minority, is a version for non A/C cars because there is more usable space available.

quote Originally posted by bnevets27: I also don't know a lot about car audio, I been learning as I go. So for example, I don't see why anyone would go through the trouble of building a large box if the TC sounds sub can (on paper) sound good in a 0.095 cu.ft. enclosure?

Answer: SPL ( Sound Pressure Level ). Some people ( me included ) like to feel their music as much as hear it. Sure a 8" under the dash in a .25 cubic foot box will probably give you enough bass to round out the system, but it isn't going to give you the back massage a 10" behind your set will. It's not going to make your hair vibrate, however prolonged exposure could damage your hearing in that situation.

Also ( while this is only true to an extent ) the phrase "there's no replacement for displacement" comes to mind. The larger the subwoofers cone area the more air it can move. The drawback is the larger the subwoofers cone area the slower it recovers so sound gets less defined the larger you go ( some subs it's less noticeable with as how noticeable it is depends on how well the sub was made ). Now, the reason I say only true to an extent is that is if you are talking a single sub. A single 15" sub is going to move more air then a single 12" ( assuming two subs of equal manufacturer quality ). For ease we will just use the driver size, a 15" would have 176 cubic inches of cone area to move the air while a 12" would only have 113 cubic inches. Now, make it 2 12" versus the 1 15" and we'd have 226 vs 176. So multiple smaller subs could move more air then a single larger sub. The advantage to smaller subs is they usually require less airspace in the enclosure, so where you could fit enough airspace for 1 15" you could fit 2 12" or 4 10" ( roughly 314 cubic inches of cone area to move the air ) or even more 8". Of course the smaller the sub diameter the higher the low end cut off frequency. Just as a hypothetical example the 8" drops down to 35 hz, 10" to 30 hz, 12" to 25 hz and the 15" to 20 hz. Most people can't hear below 30ish hz, it becomes mostly feeling at that point, so most music doesn't go down below 30 hz. Therefore a lower extension to 20 hz really is just a number unless your competeing and the test tracks include frquencies that low ( I've never competed so I'm not sure what's on the test tracks ).

Honestly, I prefer the 10" sub because it's not to big to be to slow, but big enough to give me the kind of SPL and sound I like. I've had 8" and the bass wans't strong enough for me. I've had 12" and I wasn't really impressed anymore then I was with my 10's. I had a freind with 2 18" in the bed of his truck and at roughly 505 cubic inches of cone area to move the air, that was awesome! However, the roughly 32 cubic feet of airspace his enclusure took up in the bed of his truck is just not practicle an any sense. Now consider a 10" taking 1 cubic foot of airspace , he could have had 32 10" in the bed of his truck with about 2500 cubic inches of cone area to move the air... Of course he would have needed alot more amp power to push that mant subs.

Basically it's all a balancing game based on what kind of sound you want/like. For some a 8" to round out the bottom isn't what they want/like, they want/like more. For others a 8" is perfect and for others the 8" is overkill. Really, you need to know what you want/like and see if it's acheivable ( obviously no one is going to put 32 10" subs in a Fiero). If it's not acheivable then you need to sacrafice somewhere. I wanted 10's, so I sacraficed a little seat travel and cut out the second firewall ( I wasn't willing to go with slim subs ). I honestly don't think I would have been happy with a 8" under the dash.

Thanks Khw! That helped out a lot. You explained it very well

I had that basic concept but I wasn't quite sure about it all. I feel I'm a lot closer to picking a sub and enclosure to try out and hopefully keep. Basically as I see it you have two options. More displacement is needed to get higher SPL levels. Higher SPL levels give the you the feeling of the bass. The less displacement you have the less you are going to feel the bass.

So you ether get a loss of interior space and higher SPL. Or less/no loss of interior space and lower SPL. So of course, placing a full sized 10" behind the seat with a cut out firewall is the best set up in a fiero. Good amount of displacement and little to no loss of interior space.

Couple more questions.
Does anyone know the response of the fiero?
I'm asking because of this:

quote If you subtract the in car response from the sub+box response, you can find the transfer function of your vehicle. Applying this transfer function to Winisd's calculated response can give you a much better estimate of how a sub wil sound in your car.

I've boiled my choices down to the JBL and Dayton S210. In the pictures above, the JBL is the blue line, the Dayton is the green line. In the first picture (Transfer function magnitude) the JBL's line is higher then the dayton. In the second picture (SPL) the dayton's line is higher then JBL's. I have no idea what this means.

I've been reading to try to learn how to read the information winISD provides but haven't figured it out yet.

I'm leaning mostly toward the the JBL as it looks to do well in 0.2 cu.ft and gets better in 0.33 cu.ft. and that should be the range of air space that I'm going to get under the dash. But on that SPL graph the dayton is louder. Which I kind of don't understand as the dayton is actually in a smaller box. But like I said I don't understand these charts really.

To make up for the lack of being able to feel the bass, due to the low SPL. I going to give some tactile transducers (bass shakers) a try. They sound like they could be really interesting.

It has been many years since I built this, but I would be happy to send some photos. Just PM me your address.

I did not fibreglass it, but that was part of my long-term plan - it just never seemed necessary.

Dave

quote Originally posted by bnevets27: Thanks Khw! That helped out a lot. You explained it very well

Glad I could help .

I was afraid I got a little to long winded and you might skip past reading it /sigh.

That's actually pretty nice software you used in your post. I've got older software, but I like the way it works. I can compare up to 3 woofers in the same box, or 1 woofer in 3 different types of enclosures. The one I use looks like this.



In that picture the red line is a sealed enclosure, the light blue line is a ported and the dark blue is a bandpass with an insane port gain (which would be real hard to actually build LOL ).

[This message has been edited by Khw (edited 04-29-2011).]

hhmmm I like that, being able to compare multiple subs in a single box. I going try that program out. I can do it with winISD but it gets pretty messy pretty quick.

I don't mind reading to learn. That's about all I can do, if I can't buy every sub and try them all out.

I think what it comes down to is that enclosure I posted above (black fiberglass box) made by Black Pegasus is pretty much perfect for this application. It has a good amount of airspace for a bunch of different subs and is stealth/hidden under the dash well. Just unfortunate that it can't be purchased just yet. I did talk to Fred (Black Pegasus) and he is still working on producing them. He just doesn't have a lot of time to work on building them so that is the current bottle neck.

I am contemplating building my own similar to the one Fred has made, but for a non A/C car (which mine is). There is more free space that can be used for the box then an A/C car. But I don't really want to take the dash out of my car to build it as I just got it back on the road as a DD.

I think I'm going to end up with a simple sonotube for now, maybe some additions for more airspace and fiberglass. While I'm working on that I have a sub that hasn't been doing anything, so I'm going to build a box to throw behind the seat for now and just tell the passengers to deal with it, or if I need the space leave it at home.

I would love to compare the TC sounds sub in a ~0.095 cu.ft. (or a slightly larger) enclosure to a sub in a 0.33 cu.ft. enclosure(the volume of the box Fred made). There are a few subs that do well in a 0.33 cu.ft. enclosure, so there is a few options to try them against. Unfortunately the TC sounds sub is the most expensive of the subs I listed.

Here's pictures of Dave's sonotube enclosure:

8" Dia x 12" Length = 0.33 cu.ft



One observation is that his car doesn't have A/C so that may be a factor in it fitting.

ouch the pic of that MOMO with foot prints all over it. thats why i never installed a sub there. i put one in the center, but most importantly i use square subs! many top brands make them now and its the easiest and best way to get the most sound due to no space in the fiero. i had 2 10 inch square subs and it hit really hard.

EDIT: well a dream come true is JL made a thin sub. http://mobile.jlaudio.com/p...ubs.php?series_id=30
here are some higher quality square subwoofers. http://www.mtx.com/caraudio...ers/IndexTSquare.cfm
http://www.kicker.com/Solo-Baric_L7

the kicker L7 has been around for a good number of years and has been one of the top subs ever made. the solo X is one that i am going to go for when i get more $$$ rolling in

[This message has been edited by Ruffy (edited 04-30-2011).]

Hi everyone!

quote Originally posted by bnevets27: From what I could find, the 8" subs that have full mounting depth are better subs. There are a few more choices for subs also if your not limited to shallow subs. Also if I can't really use any bigger then a 8" behind the seat and I can fit a 8" under the dash, there's not any real advantage to a box behind the seat. I knew I had seen a box sculpted to use all the available available space under the dash. Couldn't find it for a while but finally found it last night: https://www.fiero.nl/forum/F...ML/048207-2.html#p65 Estimated volume = 0.33 cu.ft (+?) Too bad they aren't being produced yet. One small modification I would like, but I'm sure I'm in the minority, is a version for non A/C cars because there is more usable space available.

You are absolutely right, there is MUCH more choices in normal 8" Subwoofer than the 8" shallows. Therefore there is more options available that will suits your needs the best. It could be from the price range, to sound quality, to the type of sound you are looking for. Like said earlier, different brands has different sound properties one to an other therefore the type of music you listen to WILL affect the speakers you will chose. To give you a Fiero applicable example:

-The dash speakers (4"x10"): Those dimensions are very hard to find. The one that I know of, and that I've tried are the Pioneer TS-A4103, the Kenwood KFC-415C and the Audiobahn ACS2041N. (Click on them to see a picture) I've concluded by testing them that the pioneer focused more on the high notes, the Kenwood was more on the "bass" side and finally the Audiobahn was in between. I chose the Kenwood since the Fiero needed more low frequencies than highs.
-The custom made subwoofer enclosure that we are developing is versatile. I'm sure that a lot of subwoofer will be able to fit. (Shallows or not) We have curently have 3 subwoofer options that we can guarantee fitment; the Pioneer TS-SW841D, the JL Audio 8W3-V3 and the Alpine SWR-843D. The Pioneer has more sound range (from mid/low to low frequencies) and the JL Audio has lower frequencies, more punch, more bass. (We haven't tried the Alpine subwoofer yet, but we have it on hand and can confirm to the mechanical fit)

Now it all comes down to what your music style is. If you prefer techno, rap or hip/hop, the more bass there is, the better it will sound. Though if you like classical, operas or blues, then you should search for better quality for the higher frequencies. If your like me and you have a vast interest in every type of music, then its trickier. You try to balance out as much as you can so that you will be able to hear clearly the maracas of Hotel California - Eagles, but you will still enjoy the bass drops from techno/dubstep music without compromising the tight "thumping" bass of a bass drum.

As for the enclosure specifications, his volume contain an average of 0.35 cu ft (There could be a slight variation from one to an other because of the fiberglassing process). The bracket design is almost done, I only need final verifications.

quote Originally posted by Khw: Basically it's all a balancing game based on what kind of sound you want/like. For some a 8" to round out the bottom isn't what they want/like, they want/like more. For others a 8" is perfect and for others the 8" is overkill. Really, you need to know what you want/like and see if it's acheivable ( obviously no one is going to put 32 10" subs in a Fiero). If it's not acheivable then you need to sacrafice somewhere. I wanted 10's, so I sacraficed a little seat travel and cut out the second firewall ( I wasn't willing to go with slim subs ). I honestly don't think I would have been happy with a 8" under the dash.

Khw,

You are absolutely right. My preferences are similar to you since I would rather want a 10" subwoofer in a car than anything else, for me it's the ultimate dimension (low frequencies vs responsiveness). Though let me add a point: The passenger compartement.

A lot of people want subwoofers in their sedans, so they put a 12" subwoofer or even 15" subwoofer in the trunk. It is known that bigger the speaker is, the more air is needed in the enclosure but that principle is the same for the other side of the speaker (The passenger compartement). For a small passenger compartment like the fiero, having a 12" subwoofer wouldn't sounds as better as a good high end 8" subwoofer simply because there is not enough space for the 12" to work properly. The subwoofer would be strangled by the lack of space and the frequencies wouldn't have the space/air required to be precise/optimum. Think of it as a ratio between the air displacement that the subwoofer makes vs the air available in the room (or car). Sometimes going bigger (Ex: having 2-15" subwoofers in a fiero... if it could be done) would just be an overkill and wouldnt sound as good as a smaller subwoofer.

I have the JL Audio 8w3-v3 in my car (8" subwoofer in a prototype of the subwoofer box above). It is astonishing what comes out of that subwoofer because it is precise, bassy and can even give you a back massage while your in the drivers seat. It doesn't have the huge bass drops of a 12" subwoofer (Even if there was a 12" in the Fiero, I don't even know if it would be able to reproduce the correct sound), but it has that snappy bass drum kick, the precision and the responsiveness that I was looking for especially because I had such a huge range of music taste.

Now,

The reason why I did my design in an A/C car is to have the biggest possible solution that can fit all the Fieros regardless of the options/years. There is more space if you don't have the A/C but I didn't bother making a 2nd design since I was already into the optimum air volume of my subwoofer choices.

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87 Pontiac Fiero GT

quote Originally posted by Black Pegasus: Khw, You are absolutely right. My preferences are similar to you since I would rather want a 10" subwoofer in a car than anything else, for me it's the ultimate dimension (low frequencies vs responsiveness). Though let me add a point: The passenger compartement. A lot of people want subwoofers in their sedans, so they put a 12" subwoofer or even 15" subwoofer in the trunk. It is known that bigger the speaker is, the more air is needed in the enclosure but that principle is the same for the other side of the speaker (The passenger compartement). For a small passenger compartment like the fiero, having a 12" subwoofer wouldn't sounds as better as a good high end 8" subwoofer simply because there is not enough space for the 12" to work properly. The subwoofer would be strangled by the lack of space and the frequencies wouldn't have the space/air required to be precise/optimum. Think of it as a ratio between the air displacement that the subwoofer makes vs the air available in the room (or car). Sometimes going bigger (Ex: having 2-15" subwoofers in a fiero... if it could be done) would just be an overkill and wouldnt sound as good as a smaller subwoofer. I have the JL Audio 8w3-v3 in my car (8" subwoofer in a prototype of the subwoofer box above). It is astonishing what comes out of that subwoofer because it is precise, bassy and can even give you a back massage while your in the drivers seat. It doesn't have the huge bass drops of a 12" subwoofer (Even if there was a 12" in the Fiero, I don't even know if it would be able to reproduce the correct sound), but it has that snappy bass drum kick, the precision and the responsiveness that I was looking for especially because I had such a huge range of music taste.

Is that your under dash sub box? If so, AWESOME WORK!

You are right, a small cabin with two 15" woofers in it just isn't going to sound as good as smaller drivers. Reminds me of the days when you saw thin wedge boxes with two 15's stuffed behind the seats of a mini truck. The Fiero cabin would be similar, and I've heard anything from a box using two 6.5" woofers and a 10" passive radiator to the skinny wedge boxes witht he 15's in mini trucks. 8's or 10's were always my favorite in that cabin size, leaning to the 10's because back then I listened to mostly rap music. I still listen to alot of rap music, but I also love me some Depeche Mode, Tears for Fears, Pet Shop Boys and Duran Duran type of music. I think it gets on my wifes nerves sometimes, lol. My mini truck was a kingcab so at one time I had two 10' and two 12's in it. Honestly, I liked the sound better when it was just the two 10's. With just the 12's it was nice also, but they just didn't have the punch the 10's did. 8's are a good option especially for a under dash enclosure and the limited space for enclosures in a Fiero without serious modification or sacrafice.

[This message has been edited by Khw (edited 03-03-2013).]

This is what is in my car 10" pioneer sub with a 1000 watt Kenwood amp. It sounds amazing! But I need to redo the power cord. It started acting up lately.

Just get a JL 6w0 or an 8" sub of similar quality, and shove it under the dash in an appropriate enclosure for it, with an appropriate amp for it. 80-100W RMS into a JL 6w0 in a proper enclosure will probably more than satisfy your wants in a Fiero.

I have a bazooka bass tube in the passenger leg area. Adds a nice decent oomph. Has the amplifier built in. 8". Fits exactly in the width of the foot well. Doesn't move at all. I will be selling it soon if you are interested. It is in a tan enclosure. I am going to put either 2 10" or 12" subs in the firewall. I like the idea of a nice JL in the center, but don't need any more attention drawn to the car then I already have. That and the behind the seats will provide the most power.

https://www.fiero.nl/forum/Forum2/HTML/126757.html

[This message has been edited by mitchjl22 (edited 03-05-2013).]

quote Originally posted by Khw: Is that your under dash sub box? If so, AWESOME WORK!

Yes it is. I currently have 3 prototypes working in cars:

-Mark 1 - In my car, JL Audio 8W3-V3 mounted under the dash
-Mark 2 - In my brother's car, Pioneer TS-SW841D waiting to be mounted
-Mark 3 - In my father's car, JL Audio 8W3-V3 mounted under the dash

I have a small batch started. The big hold up is the bracket design (I'm at the 5th design right now). Its a nightmare because of the weight, the space, the movement you don’t want (You want the enclosure to be static), keeping the vibrations to a minimum... etc. I explain everything in my thread.

quote Originally posted by Khw: ...leaning to the 10's because back then I listened to mostly rap music. I still listen to alot of rap music, but I also love me some Depeche Mode, Tears for Fears, Pet Shop Boys and Duran Duran type of music.

Ah! That explains it!

When I'm setting up a car sound system, there is always some important questions to ask yourself or the client:

-What is the budget?
As this one will guide you throughout your shopping deciding if it’s not good enough or if it is unrealistic. It's a bargain between the money you have available and the best quality there is. You could make the perfect sound system setup possible in a car, if it costs 500 000$, it doesn't mean the client will pay for it.

-What kind of music will it play?
A different type of music uses different frequency range. If you listen to classic music, you will need to focus more into the tweeters (High frequency notes) since it will allow a clear imaging of the instruments playing giving it clarity and a crisp sound. If it's rap, techno or dubstep that you listen to, you will need to focus more into the subwoofers.

-What are your earing preferences?
Everyone hears differently. You could set up your sound system to a perfect balance and someone else will think it has too much bass, or that the high notes are too aggressive. It could be because of his preferences, but it could also be because he simply doesn't hear the same thing as you. I remember telling a friend about a certain song which was only a girl signing along a piano. When we first listen to it, I told him to look for the voice reverberation (echo) after each line the signer sang but he couldn't hear it. (It was with high quality headphones) It took him a stereo sound system setup of 7 000$ for home, and a relatively high volume for him to be able to hear what I was talking about. When I'm talking about earing preference though, I'm talking about if you prefer a song while it's played flat (Without any sound enhancement) or you prefer the same song with more bass or more treble. If so, it is better for the designer to take it into consideration when making the setup.

-What kind of sound quality is he searching for?
This is simple; I will use stereotypes to describe this question. A teenager will want a car sound system that will impress his friends and that will be loud. I have seen teenagers put thousands of dollars into subwoofers and amplifiers while he left his speakers stock. I can guarantee you that the system was loud and punchy but there was no quality whatsoever. As soon as he was driving his speakers a little loud, his stock 4x6 speakers were making so much distortion that it made it impossible for me to enjoy the music I was listening to.
In the other hand, there is a certain limit of quality that you will be able to reach into car audio. Most of the time, it is limited by the budget or simply it's not what the customer wants. (He just wants a big "boom box") If it's not limited by the budget, it is limited by the technology. Nothing beats a home stereo for the same price since it is near impossible to have audiophile quality in a car. A car has so much more variables into counts like humidity, temperature, speaker placement vs position of listener, space, road noise, engine noise... etc. Therefore the customer should be informed that no matter how much money he will put in the car sound system, it will probably never reach his audiophile home stereo.

-What are the sacrifices he is ready to make?
In every car there is a sacrifice to make since as soon as you put a subwoofer in, you lose some space. (Most of the time it is trunk space) At what point is he able to give in his car's practicality for a better sound. Also can he sacrifice the aesthetics by changing the speaker placement elsewhere for optimum performance, or simply fit bigger speakers in the same holes. As soon as you add something, something else will be removed.


Now there is one thing to remember, you need to make a combination, it’s not as simple as slapping some parts together and hoping for a good result. For instance: the first thing/most important thing to change and have great quality is the receiver/head unit. You can put the best speakers possible in your car, if the head unit is sending poor quality music, the music will sound poorly. Therefore everything is a balance between price and quality. You probably don’t want to invest your full 2000$ budget into the subwoofers and leave the rest stock unless the only thing you want is bass. It’s a matter of dividing your budget so that you get similar quality throughout the system so that the quality isn’t strangles by one component that is from poor quality.

Therefore the key is balance within the budget and optimize the setup for the taste and the music style of its owner.

quote Originally posted by Khw: I think it gets on my wifes nerves sometimes, lol.

lol it could be worst though! Your type of "music" could of been:

-Nature Soundtracks
-Whale Chants
-Or even worst: Engine Revving Soundtracks (I don't know why, but girls seams irritated when they hear that in videogames) lol

Fred

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87 Pontiac Fiero GT

quote Originally posted by bnevets27: Here's pictures of Dave's sonotube enclosure: 8" Dia x 12" Length = 0.33 cu.ft One observation is that his car doesn't have A/C so that may be a factor in it fitting.

That definitely needs a screen... looks like someone has been kicking it.