924Board.org

[crackmonkey]

so you didn't have to cut the metal on the door i guess it just fits into the hole that is already there
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'78 924

[Neil924]

[Joes924Racer]

Im happy with what I got the thumps are pretty
good handle what there rated. Now I need a
bass in a box and some more speakers & a amp.
The 5x7 are good for the doors 6x9s for a rear sides
and a bass in the spare tire hole with a 2 channel amp
to carry the rearsides and the bass. That would work.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[garyj]

Dosen't the window come down on the speakers? Like the speakers are too deep in the door so when you open the window all the way the speaker gets hit inside the door? I took the door panel off of my car for another reason and was thinking of putting speakeres in, but saw when i closed the windowthe glass was right next to that "factory opening", like the speaker would be too fat to put in the door without the window coming down and hitting the speaker when cranked all the way down? Any comments on that? I was really thinking about doing that because the acoustics and speaker placements in the car are horrible, but then i noticed the window would come down on it...
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"Spent my days with a woman unkind smoked my stuff and drank all my wine
Made up my mind to make a new start,
Going to california with an aching in my heart."
-Led Zeppelin

[Finbarr]

If it's of any relevance, my PO had fitted round speakers to the doors but made a complete botch of it. They weren't screwed into the metal of the door, just the soft door panel which was coming loose. I think they'd done this because they didn't want to cut out any metal from the door, but the hole was too small to get the round speakers all the way in so they just sort of flapped around. The sound from them was weak and rattly, and even if I'd cut out the metal for the speaker to fit flush with the door panel I think the window mechanism would have hit the magnets on the back. The door panel had been cut out round so I couldn't have gone back to stock speakers if I'd wanted to.

I got a couple of spacers - just plastic rings - which I bolted really securely through the door panel into the metal of the door. The speakers then screwed on to the front of the ring - again, really solid - you could happily slam the doors shut now using these things as handles. They look a bit odd, because the stick further into the car than they need to at the moment (about 2 inches) but the sound from them is fantastic - good, deep punchy bass because of the combination of the solid mounting and the use of the whole door as a speaker cabinet. I will trim them down to about an inch at some point but there's more important things to do for now.
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1980 931 (with the odd electrical quirk...)

[Joes924Racer]

the windows roll down all the way, I want to place a spacer and use a longer screw to attach the handle for the window it needs to be brought out 1/2. It just grazes the speaker as you turn it.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

Bought some stuff for my stereo today
like a pair of 400 watt 6x9s.



4 175 wat 8" subs.



Looking at amps right now. 4 channel or 2.
I dont know yet.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

one little 2 channel 250 watt amp.


Thimk Ill get a couple more amps or maybe just a
4 channel
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[kye]

I've been enjoying the sounds of (what I assume to be) the factory units for a month or so now with my upgraded head unit, and recently I augmented the system with a 10" sub.

my opinion on sound in the 924 is that the factory speakers are not too bad, and money can be better spent elsewhere if you're on a limited budget.
The best improvement over a factory system is going to be replacing the head unit for a new one. Newer units play mp3s, have nice amps built in, and give a much better sound than you'd expect. a bit of EQ and you've got a good sound overall.

other options:
* get something to do the bottom end (even if you only listen to acoustic folk music). traditionally this would be a subwoofer, but it could be a pair of 6x9s if you're not looking for major volume. the 6x9s you could run off the head unit, but the sub would need a separate amp
* replace the factory speakers with more 4x6 units. with a bit of EQ they'll get their top end back, and they'll give a nice sound
* add on a separate tweeter to the existing rear speakers. the factory speakers will do midrange and midbass nicely even if they're old, so adding in a small tweeter (and filtering off the factor units) will give you a good stereo image and put the sound in front of you.

things to consider when buying car stereo equipment:

don't shop for Watts, shop for sound. the retailers love to sell you speakers that can swallow huge amounts of power, and big amps that can deliver it. what they don't tell you is that these systems (at entry/mid level pricing anyway) won't go louder than lower powered systems. (and may not sound any better either)
the reason this is true is because there's only so much sound a speaker of a physical size can make. so, how do some speakers swallow more power? they're less efficient! i've seen subwoofers that range from 77dB per watt, to 100dB per watt efficiency. to put out music at 115dB (bloody loud) the 100dB speaker needs a 32Watt amp. for the 77dB speaker to give you 115dB of sound, it requires a 6208Watt amp. (yes, more power than your average rock concert. how do the PA guys do it? they have efficient speakers!)
the rule is for every 3dB more efficiency the speaker has, it needs half the power from the amp to make the same volume sound.
and less power requirements from your amp(s) means that you're not putting as much strain on your alternator (or other electrics) and it will go for a lot longer with the car turned off before flattening the battery.

when building a subwoofer, don't just buy a ready-made box from the shop and whack it in there. different speakers require different sized boxes. normally the manufacturer will give a couple of recommended box sizes with the speaker, with various lower frequency numbers attached to them. if you don't look at them, then it's a hit and miss process, and you may never know how good what you bought could have sounded in the right box for it. the size of the box is the volume of the box (in Litres or cubit ft) and the shape doesn't really matter.. having a custom made box means you can fit it into your car neatly)
of course, if you can buy a box from a retailer that's the right size, then go for it!

don't get hung up the f3 parameter when you're wanting low bass.
the f3 parameter tells you at what frequency the speakers bass response is starting to trail off, IN FREE AIR. when a speaker is in your car it is not in 'free air' and therefore some interpretation of this number is required. I can't remember the exact formula for it, but if you put in all frequencies into a room (or car) then you get more bass than treble because the room emphasises the bass. the lower the frequency, the more emphasised it becomes. the frequency response will start rising from being flat at a certain frequency, which depends on the room size (volume). the smaller the room, the higher the frequency where the bass boost comes in. a car is very small in comparison to a room, and the 924 is a small car.
the sub in my car has an f3 of about 100Hz (higher than most door speakers) but because the output at the lower frequencies are boosted by the cars small volume, it evens out. I haven't tested it, but I have to turn down the bass because it rattles the hatch sometimes. it does low bass without problems (ie, drum n bass, so real low bass)

knowing about the bass boost in cars, sometimes you've got a choice to make between a sealed box and a ported box. manufacturers often give sizes for both. in a car with the bass boost, you can get away with the sealed option (which will not have as good bass extension as the ported box) and it has many advantages to the ported box.
ported boxes are generally bigger, have less solid transients (ie, slam), and below a certain frequency they don't offer the driver any protection against over-excursion. sealed boxes do offer this protection.
the trade-offs are slightly less efficiency, and the less bass extension, which (of course) doesn't matter much in a car.

when looking for a retailer (or person to get audio advice from) look for someone that is willing to tell you the advantages and disadvantages of everything. audio reproduction is a field where you are constantly trading off some things for other things. if you're comparing anything still done today (ie, not technology that's outdated) then there is always a downside and an upside (even if the upside is that it's cheaper).. any retailer who tells you that something is better than something else without any conditions on the statement does not know the whole story, or is lying to you. go elsewhere!

home speakers drivers can be used in cars.
traditionally, home speaker drivers have an impedance of 8ohms, and car drivers of 4ohms. this is really the only fundamental difference between the two. in reality, home drivers are more like 6ohms, and car drivers are optimised for small boxes and home ones aren't. but the different ones available do vary, and sometimes using home speakers can be fine.
when connecting a speaker to an amp, less impedance (less ohms) will cause the amplifier to supply more power (if it can) so it is often louder to use the 4ohm driver (assuming the two drivers are of the same efficiency)
the rules of putting in multiple speakers with one amp channel is that when you put two identical speakers in parallel, the impedance is half that of a single driver, and when putting them in series, it's double that of a single driver. but, having two drivers putting out sound doubles the volume too.
so, if you put them in parallel, you could double the amps power output (if the amp was up to it) and you will double the speakers output, giving an overall improvement of 4x. if you put them in series, the amp might give half the power, but the speakers would put out double, so it would be the same volume.
when combining speakers in parallel, you have to be careful not to go below an amplifiers minimum impedance. if you do, you can blow up the amp.

the subwoofer I have in my car is a 10" home driver, with about 6.8ohms impedance, in a sealed box, running on a mild powered car amp (50W or so)... the driver cost me AU$150 and was the subwoofer for my home studio monitoring system, which was good enough quality to criticise the way most CDs were recorded. i'm upgrading the home setup, and so the car got the sub driver for free!

that's all I can think of for now, but feel free to ask questions. I may not know that much about cars, but I know a lot about speakers and audio gear!
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it's funny, but when they said "Anything is Possible", that's exactly what they meant....

[Joes924Racer]

Well 2 of the subs will be in sealed boxes and fit in the spare tire
hole I was gonna make boxes for the other 2 subs to fit in the sides
like where the side markers are in those holes on the rear sides Im getting another amp or 2 and a eq somday though i also found a nice fiber glass
laminate that will let me make a nice covering for what ever I build
it comes in silver,black, tan, and white the speakers in the door are gonna be reset and that whole area of the door panel will have a piece of the tan panel screwed in place. The speaker company makes a nice set of
boxes for the 6X9s and they offer a few types of tweeter that is flush mount
type so they go good in the dash if I go that way. the laminate is used
in commercial wall covering in bathrooms and kitchens it has a bumpy
texture I used some of it in patching my center console though it was the white i painted black. I checked a few places and found that it comes in those other color options so Ill get a sheet of the tan for starters. over
here we call it frp board.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

Still waiting for something to arrive
As Im taking a road trip early this evening
like at about 6 pm to the coast for a few days
it would be just perfect if I had all this installed.
The door panel around the speaker there is gonna
get a newlittle panel there cut out of the frp board
or better I think Ill use some nice yellow formica
thats counter top material so Im really gonna modify
the door panals I have Im gonna like cut that part off
of the door panelwhere the speaker is and just tuck
the material under there.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

Still waiting on my amps though I have recieved my
6x9s and subs.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

To tell the truth I cant belive no-ones made a sub box
to fit in the sides in back of the rear wheels..Im maken
a sub box that fits the spare tire hole..

A sealed box with a port, - so you get air movement in front
& in back of the speaker for that whump sound theres gonna of
course be a sub crossover in it. Im still waiting on the amp
though..the 4 way 6x9s produce to much mid-range. I bought
pre-made boxes for those. They dont fit any where really though
so a funky shaped box that fit the sides in back of the rear wheels
is the answer.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

The sub amp is still in the mail hasnt reached me yet...I can
barely
hear the subs with out the amp, the 4x6s are nice in the boxes.
though 4 way 6x9 is a little to much mid range Im sure the amp
pushin the subs will make everthing just fine.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Joes924Racer]

heres the amp this is hopefully gonna be nice sounden.

_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.