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Looking for some "sound" stereo advice
#1

Hi all,



In some ways my queries here should follow-on from Paul W's informative post about his Becker Traffic Pro install. I've learned a lot in the last couple of weeks reading this forum and others - but still have a "couple" of questions I hope you can answer.



Context



1992 coupe

New Becker CDR-220 - purchased from SW stereo - Stefan there is very helpful.

New JL Audio XD 400/4 amp

Speaker upgrades - doors first, rears to follow

Dynamat everywhere - well, not Dynamat, but Stinger Expert Roadkill bulk pack - less expensive.



Questions



Power wiring for the amp - conventional wisdom says run power right and speaker pairs back up on the left, don't ever run them parallel, and if you cross, cross at 90 degrees. So the trick is crossing to get back into the right door, and back to the right rear (which as I think about this in the abstract seems especially difficult.) What wire runs have worked for people in the past?



Oh - one possible wiring topology would be power up the middle next to torque tube - then speaker wire can travel left and right without any bother. BUT - can't see a path through and around the rear seats. Looks like the rear lighting harness comes up about amidships behind the seats but i don't see a way to take advantage of that path either. Anyone done this?



Door speakers - I foolishly thought I could simply retire the rotted-out mid-range speaker, and replace the low and tweeter with speakers of my choice. But my friends at Crutchfield (I'm local - so they're a good resource) say I need to buy a matched component pair with proper crossover circuitry. True? I'm ready to pop in JL Audio C3-525 in the doors, paired with new JL C3-650's in the back. Anyone done the "tweeter mod" that's been posted here with that JL tweeter?



Stock wiring - My car has two 2-channel amps under the seats - see the attached pics. Initially I was hoping to keep and use the existing wiring but now not so much. Check out the wiring diagram - who can explain to me why the right amp drives right door and left rear, and the left amp drives left door and right rear? The wiring diagram labels the amps as "rear" and "front" but those labels don't make sense either. Anyway, it's complicated enough I just want to rip it all out and re-do. Any advice appreciated.



JL XD 400/4 - this amp is small and fits nicely in the right rear cubby. Haven't figured out the mounting yet. It's really no bigger than the Alpine CD changer I just removed. (Ha - the changer is available if anyone wants it.) The amp says I need a test-tone CD and voltmeter to properly set the input sensitivity. I found a couple of links to 1khz and 50hz audio files to make my own CD with. Would this be the recommended path?



Anyone have experience or recommendations regarding the Crutchfield amp install kits? Or should I just assemble what I need separately?



Ha - and yes, Flash, someday a parametric equalizer but I've spent my wad and right now I just need me some radio and music to get me to work in the morning. My standards are high, but I have to decide to self-arrest on this slippery slope at some point! :-)



Thanks very much,



Jeff in VA
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#2

As for the power wire running opposite of the speaker wires, I can atest this is true. Long ago before I knew better I ran both along side eachother in my old 4Runner. I would have this high pitched whine that wasn't always there but often. Since this was long before the internet, I visited a couple stereo shops and one guy mentioned this could be the problem. It was a pain to back everything out but once I did, whine was gone. I'm not sure exact 90 degree crosses are necessary but keeping the two away from one another is a smart idea
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#3

Biosurfer - "keep 'em apart" certainly seems to be the consensus.



But hey! look! In the pic of the stock 2-channel amp, the 12V red power wire, with the 5V fuse, runs right in the same package as the rest of the audio wires. I'm not an electrical engineer so I have no idea why Porsche gets away with breaking the rule here.



I just got off the phone with Stefan @ SW (on a Sunday, no less - he asked me to call him) - he is making it simple to chuck the original wires. He's making two custom adaptors for the head unit - one that will plug right into the existing stock 6-pin power/antenna socket, the other with the RCA pigtails I need for my amp power-on signal and audio feeds to the new amp. Excellent, excellent customer service.



J
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#4

Regarding test tones, yes its the best way to do it but only really necessary if you are trying to get max volume out of your system. If you do use test tones bear in mnd that most music is recorded quieter than a 0dB test tone, so you probabaly wont get max volume anyway. Most advice using a -3 or -6db test tone.

Most of all though, just use common sense!
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#5

regarding the front speakers, you can just use the separate tweeter and 5.25 of the JL setup. i just did it in a cab. it does mean you have to cut the OEM tweeter out of its tweeter housing, and glue in the JL. also, there will be some minimal modification to the woofer housing to manage the JL, as well as some tweaking of the grill to have it clear the rubber surround during full excursion.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#6

re: input sensitivity



LOL - no I don't plan on volumes that will endanger my health! But regarding this test tone/input sensitivity business I'd still like to dial it in correctly - could I just take my car into a local installer and have them tune the system and set the input levels?



re: JL component set



Flash - thanks - that's exactly what I plan on doing - use the component crossover and replace the tweeter.



jg968 posted a nice diagram of the 5.25 speaker dimensions - I haven't checked the horizontal dimensions but as for depth, both the JL Audio C3 and C5 5.25" speaker are 60mm or less (dimension "G" in the pic). One worry is that both of these speakers the "Frontal Coaxial Tweeter Protrusion" (dimension D) is 5/8in or 18mm - but this won't be a coaxial install.



Flash could you expand on what mods will be required to get this speaker to fit our stock plastic housings? I have read about and am prepared to trim the perforated metal grill back so the edges don't cut the cone - but what else?



As for the rears: The C5 6.5" rear speaker coax tweeter sticks out 1/2" and that speaker is 66mm deep. The C3 650 needs 3/4" for its tweeter. Any problems there?
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#7

The front midbass speakers in a 968 are mounted very close to the underside of the armrest and point downwards. It means that speaker fitment depends both on depth (G) AND also the basket/magnet diameter ©.

I had some Alpines which touched the bottom of the armrest when fitted due to the size of the magnets. Eventually replaced with some Morels which were slightly deeper but with a much smaller magnet.

Bottom line, the only way you will know is to try and install or buy something that is already proven.



Regarding gains, start with the amp gain on minimum and your headunit turned up to 75% of its max volume. Then slowly turn the gains up until you hit the highest volume you will ever play. Then never turn your headunit above the 75% volume mark.

You are aiming to keep your amp gain as low as possible.



Regarding mods required to make the speaker fit, once again you wont know until you try for your speakers. For both my Alpines and Morels the 968 mount opening was slightly too small so I had to use a file to remove a little plastic.

You are trying to get a solid mount which won't resonate whilst creating an airtight seal between the front and the back of the speaker. I made a foam gasket which helped with this.
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#8

dry664, Which type of morels did you use? I'm thinking about upgrading my door speakers too.
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#9

i did not have to cut the grills at all. they only needed some bending at the tabs. there is not enough air volume in the front enclosure, so an airtight seal there is not a good idea. don't expect to get a lot of bottom end out of a 5.25" speaker though.



the grill needs to be massaged a bit at the rear too, but not much. the rear speaker enclosure mod will help a lot back there with bottom end.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#10

[quote name='Ernie' timestamp='1407169096' post='160849']

dry664, Which type of morels did you use? I'm thinking about upgrading my door speakers too.

[/quote]



Tempo's.
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#11

[quote name='flash' timestamp='1407169361' post='160850']

there is not enough air volume in the front enclosure, so an airtight seal there is not a good idea.

[/quote]



So open up the waterproof membrane so the speaker can breathe into the door? Surely not a good idea to have speaker backwaves leaking into the cabin, especially around the woofer? Will just make any speaker sound wheezy.
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#12

it's a crappy spot for a speaker to be sure. i'm going to be playing with it a bit when it gets back here next month. i think there is enough room behind the magnet to open it up, but still provide a weather seal. it's either going to be that, or really seal it up and port it.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#13

dry664 thanks for walking me through the basics of setting the amp inputs.



GOOD POINT about dimension "C". I'll be thinking about that.
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#14

[quote name='apex' timestamp='1407201147' post='160866']

dry664 thanks for walking me through the basics of setting the amp inputs.



GOOD POINT about dimension "C". I'll be thinking about that.

[/quote]



No problem. Just ask if you want anything more in depth. Better to ask a stupid question that blow up your speakers!
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#15

Thanks for the offer, dry! I may have to take you up on that. BTW the Becker head arrived to day and I love it. With wiring harnesses all ready to plug and play. I'll post pics soon.
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#16

OK I'm so excited may I just share? <img src="/forum/images/smilies/968/biggrin.png" class="smilie" alt="" />



Love the look of the Becker. Simply effin' perfect for the car. Ha. Can't quite get it all the way in yet - one step at a time. There is a stock "cage" that needs to come out of the slot - this allows the Becker to slip in nicely, up until the point it hits the springy tabs in the back.



My man Stefan at SW Stereo has been a terrific help. Check out one of the harnesses he made for me. Plug-n-play RCA out. Another one lets me connect directly to the stock flat six-pin din connector. Yet another gives me a iPhone 5 charge/play cable. Said "no" to bluetooth for now. Convenient charging is more important to me.



Ryan here confirms and has shared pics of this install of JLAudio c3-525 speakers in the doors - they fit directly no problem. Awesome. Thanks again, Ryan.



Next step - figure out mounting for the amp in the right cubby, and - fingers crossed - find a way to run power down the center of the car.
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#17

Use best practice Apex, power and remote down one side, speaker cable and RCA's down the other. Use the largest power and ground cable the amp will take and keep your ground as short as possible.

Do it properly so you only have to do it once.
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#18

looking good
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#19

Jeff, you meant Ryker, not Ryan! Lol



This is what I emailed directly to Jeff. I have been meaning to do a write-up of the whole process. My entire system was installed in Flash's Garage MaHaul. This is regarding the front speakers but we also installed an amp, equalizer, rear speakers with rear speaker enclosure mod, and an 8" sub in the rear cubby that sounds absolutely amazing. I included a photo of the sub and the rear C3-625 as well.





Hey Jeff,



The C3-525's work great in the stock location. I used one screw hole in the crossover, and screwed it into a hole that is already in the plastic. I tried a couple of locations but the one pictured here allows the plastic to go back into place without a problem. The speakers fit perfectly and screwed right in. Once I got it all together though, it sounded like I blew one of them. I pulled it apart, and as you can see in the bottom photo, they were up against the grill. I used a grinder, and carefully ground down the metal. I say carefully because you do not want to damage the felt. It was pretty easy, I took the metal down from the 90 degree bend to make it flat from screw to screw, and the speaker no longer touches anything. It eventually went back to its original shape.



As for the tweeter, I pulled out the stock tweeter, and siliconed in the JL. Later, I installed different speakers into my other car (no Davebert's car), and I realized I could pull out all of the guts, leaving just the grill. I don't have a photo but I think you will see what I mean. You can pull out the stock tweeter, and it leaves a plastic piece inside the grill, so pull that out as well. I used lineman's pliers.
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#20

lol - you forgot the part where i used a couple of strips of double sticky back tape on the backs of the crossovers. it took a little playing around to find the right angle for the crossovers, and i had to dig up the right screws to hold both those and the speakers, but in the end, the subassemblies worked out well.



as for the tweeters, they popped out of there fairly easily. a quick shot with the dremel and there was a good landing pad for the new tweeter. a bead of silicone glue and a night of curing, and everything was ready.



the sub was fun. which reminds me, i need to get back to that and create the baffle plate template drawing so i can post it. the results were really good, and really filled in the bottom end.
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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