Stereo layout

[gtkid2]

Any suggestions? I was thinking cut the back deck and fit two 6x9 speakers and fit a single 8" sub into the "back seat" (a.k.a. wood board)

[BQS4]

Originally Posted by gtkid2 Any suggestions? I was thinking cut the back deck and fit two 6x9 speakers and fit a single 8" sub into the "back seat" (a.k.a. wood board)

Sounds like a plan to me. Numerous layouts have been tried, the only thing I suggest is you check the depth of the sub into the back floor.

[Dale .D]

Originally Posted by gtkid2 Any suggestions? I was thinking cut the back deck and fit two 6x9 speakers and fit a single 8" sub into the "back seat" (a.k.a. wood board)

I would replace the quarter inch back board with 3\8ths ply.

[CDN OpelNut]

I fit a 10" sub in the deck with a 3/8" spacer. There's room, but not much air to move around.

[gtkid2]

did you build a box and screw it to the underside of the board? I'm working with a rockford fosgate 8 and it has plenty of room between the board and body... would 3/8 fiberboard be better than plywood?

[CDN OpelNut]

Originally Posted by gtkid2 did you build a box and screw it to the underside of the board? I'm working with a rockford fosgate 8 and it has plenty of room between the board and body... would 3/8 fiberboard be better than plywood?

I mounted the sub from above behind the passenger seat where the cavity is deepest. No box, I just sealed all the gaps underneath. I could do that because I covered the top of the tray in a matt black arborite - no carpet. On the other side, I built a box and put two small amps and a crossover under a plexiglass cover. Looked quite nice.

[SteveGT]

I personally would not recommwnd plywood...if your like me you may crank it up some....vibs will delaminate plywood...I am using 3/4" fiberboard on my install

SteveG

[opelwasp]

I put two 10" in my spare tire area. I just removed the wood back there and built the base of the box using the spare tire tray as a pattern. I also cut holes under the triangle windows to fit 6x9's. I put 6 1/2" in the doors and tweeters on ends of the dash. I cut a recess into the rear package tray and covered it with Plexiglas to house my 1200 watt amp.

Proper speaker boxes are made from MDF particle board. Any other type of wood will soak up too much moisture or as said before de-laminate due to vibration or moisture.

My next set of boxes and speaker enclosures will be made from custom molded fiberglass.

[markandson]

Originally Posted by opelwasp I put two 10" in my spare tire area. I just removed the wood back there and built the base of the box using the spare tire tray as a pattern. I also cut holes under the triangle windows to fit 6x9's. I put 6 1/2" in the doors and tweeters on ends of the dash. I cut a recess into the rear package tray and covered it with Plexiglas to house my 1200 watt amp. Proper speaker boxes are made from MDF particle board. Any other type of wood will soak up too much moisture or as said before de-laminate due to vibration or moisture. My next set of boxes and speaker enclosures will be made from custom molded fiberglass.

No good Keith, fiberglass will move and resonate, stick with the MDF. BTW I don't know if everyone realizes that there is a specific volume that should be behind the driver. It is a number that can be calculated but it is related to the free air resonance of the driver, driver surface area, the frequency you are tuning for, etc. In college I did a whole engineering project on it and built several enclosures for my system back then.

[oldopelguy]

Originally Posted by markandson No good Keith, fiberglass will move and resonate, stick with the MDF.

Not quite, most high-end custom boxes have at least one side of them in fiberglass. Granted, it's usually 3/8-3/4" thick, but still. I've built dozens of custom boxes out of fiberglass and whenever it's a tight fit it's the way to go for sure.

[markandson]

Originally Posted by oldopelguy Not quite, most high-end custom boxes have at least one side of them in fiberglass. Granted, it's usually 3/8-3/4" thick, but still. I've built dozens of custom boxes out of fiberglass and whenever it's a tight fit it's the way to go for sure.

I could see using it at 3/4" thick, but that sure is a lot of material, that was not what I envisioned when Keith mentioned fiberglass.

[opelwasp]

Originally Posted by markandson No good Keith, fiberglass will move and resonate, stick with the MDF. BTW I don't know if everyone realizes that there is a specific volume that should be behind the driver. It is a number that can be calculated but it is related to the free air resonance of the driver, driver surface area, the frequency you are tuning for, etc. In college I did a whole engineering project on it and built several enclosures for my system back then.

I'm not Keith, the name is Chris. Anyways. I used to build custom enclosures for a stereo shop, so I do know what I am talking about. Yes every speaker has specific calculations to get the best sound. Whenever you get a speaker, primarily a woofer, you need the Theil-Small parameters. Once you have these specs you can design a very good sounding box. You will be able to build/tune it to you particular music tastes. Most people don't give a rats ass though and will just buy an over priced box off a shelf. I prefer to build my own. My last box was a 7th order band pass, amazing bass SPL's, but if you use too much power you will invert your woofer cones, heavy as a SOB too. You will need specs like:
Vas [Liters] Equivalent volume
Qts Total Q-factor
Qes Electrical Q-factor
Qms Mechanical Q-factor
Fs [Hz] Resonance Frequency
Sensitivity [dB] SPL dB at 1W, 1m
Max Power [W] Maximum input power
Lower freq [Hz] Lower usable limit
Upper freq [Hz] Upper usable limit
Rec. Filter freq [Hz] Recommended frequency, steepness of filter
xmax [mm] Max excursion from center at normal operation
Moving mass [g] Weight of moving parts
Disp area [m2] SD, Effective piston area of cone
Disp Vol [cm3] Displaced volume = xmax * 2 * SD
Re [ohm] DC resistance
Z [ohm] Impedance of coil
L [mH] Inductance of coil

[West Coast GT]

It seems to me, in the end, to be a moot point.
Between the wind noises with windows down, the whine produced from just about every Opel's scored gear in the rear end, the road noise, and hopefully a lively exhaust note, we can not hear the music clearly anyway.

[michaedo]

ain't that the truth. These are noisy little cars.
The only time I can hear anything at all from
the radio is when I'm at a standstill.

[74Opel1900]

Originally Posted by michaedo ain't that the truth. These are noisy little cars. The only time I can hear anything at all from the radio is when I'm at a standstill.

All the more need for a good sound system. I'm also currently deciding what to do about a system for my 2 door Ascona. It never had a radio so the dash is uncut.

[gtkid2]

Thanks for the ideas... I plan on installing a pioneer deh3800 face (have one in my civic and it works great) and 6x9s in the sides under the corner windows...
maybe tweeters up front? anyways thanks

[markandson]

Originally Posted by opelwasp I'm not Keith, the name is Chris. Anyways. I used to build custom enclosures for a stereo shop, so I do know what I am talking about

Sounds like you were insulted that I got your name wrong...sorry....too many guys with handles that start with Opel. Glad to hear you know about boxes, not many people do.

[RallyBob]

Originally Posted by 74Opel1900 All the more need for a good sound system. I'm also currently deciding what to do about a system for my 2 door Ascona. It never had a radio so the dash is uncut.

My '72 wagon has an uncracked and uncut stereo-delete dashboard. The receiver is in the glovebox.

[opelwasp]

Originally Posted by markandson Sounds like you were insulted that I got your name wrong...sorry....too many guys with handles that start with Opel. Glad to hear you know about boxes, not many people do.

Insulted? No. Now if you called me Dave Grant or Nobody I would have been insulted.

The biggest problem I found with building boxes was finding out how big they had to be. If you go by the numbers sometimes they have to be monstrous, which sucks for a small car. Speaker choice is very important.

Also if you are going thru all this work to build a box, an electronic crossover is best to isolate the hi/med/low frequencies. At one time I was running 8 channels. Two 4 channel amps.

Oh, by the way with 1200 watts in a GT, you're gonna hear the music just fine. So is everybody 50' from you.

[74Opel1900]

Originally Posted by RallyBob My '72 wagon has an uncracked and uncut stereo-delete dashboard. The receiver is in the glovebox.

I was seriously considering NOT cutting the dash but then I thought to myself "Isn't that what that empty spot is for?" I'm not going to leave the dash uncut just for the sake of having an uncut dash. I'd rather have the room in the glove box also. I've made the decision to cut the dash. I don't want to mess with a remote and batteries. Also the glove box would need to be cut on the inside for the head unit I want. The head unit illuminates a nice blue to match my car too. I did decide to only put speakers in the rear deck for now. I was considering getting custom kick panels made but decided I can always do that later if I want to improve the sound. In the future I may put a sub woofer in the trunk in a custom panel opposite the spare tire. I am also considering putting two 3.5" speakers where the single stock speaker goes. They make an adapter for this application.

[blancojp]

Originally Posted by RallyBob My '72 wagon has an uncracked and uncut stereo-delete dashboard. The receiver is in the glovebox.

My '72 Ascona has a massive stereo system. It has a single working speaker and plays a single AM station on both AM and Fm. The rear speakers are the air suspension type, they have no magnets and no bolts holding them in place.

No matter what anyone says, no two equal cars will sound the same even with the same equipment. It takes power to move a voice coil and most stereo systems in the market do not have enough base output to move the coils effectively. So you go into amplification then equalization and then a sub-woofer.

After all, if its too loud you are too old!

Inside my '69 Chevelle I have a Pioneer Am/FM receiver and the CD changer is in the trunk. The receiver is just a pre-amp and can't be connected directly to a speaker without an amp. Sound power comes from 4 Sankio 60W Mono class A amps driving 4 5x7 Yamaha 3-way speakers. The sound is unreal and rivals the big dollar systems any day of the week.

Plan your system and don't overpower just to compensate for lousy acoustics.

[opelwasp]

Originally Posted by blancojp Plan your system and don't overpower just to compensate for lousy acoustics.

Oh, my system was planned. I just like heart stopping bass. Or at least I did when I was in my 20's.

[74Opel1900]

Here's what I'm getting installed along with the price of the equipment. I shopped around and Dealercostcaraudio has the absolute cheapest prices along with free shipping on orders over $99.

5.25" Speakers: JL Audio VR525-CXi $89
Head Unit: Kenwood KDC-MP538U $126
3.5" Speakers: Boston Acoustics S35 $39.99

Total cost of equipment: $254.99
I'll need to get an antenna but those are cheap. Professional installation shouldn't cost more than $200 (might seem high but they need to make a wiring harness too). So for around $450 I think I'll have a fairly decent setup.

[RallyBob]

Originally Posted by opelwasp Oh, my system was planned. I just like heart stopping bass. Or at least I did when I was in my 20's.

You mean back when you were a 'yute'?

Funny though, I had a decent stereo in my '73 Ascona back during my mid 20's-early 30's, and I seldom turned it on. I preferred hearing the engine on that car whenever I drove it. I was constantly looking for tunnels just for the acoustic effect when I drove through them @ 7500 rpms....

[opelwasp]

Originally Posted by RallyBob You mean back when you were a 'yute'? Funny though, I had a decent stereo in my '73 Ascona back during my mid 20's-early 30's, and I seldom turned it on. I preferred hearing the engine on that car whenever I drove it. I was constantly looking for tunnels just for the acoustic effect when I drove through them @ 7500 rpms....

Tunnels I love tunnels. Heck I get a little rush just driving under an overpass.