"Invisible" audio for the Porsche 914 Options

[horizontally-opposed]

Plans to go for a drive in my 914 this weekend were dashed by yesterday's stay-at-home alert, so I finally dug into a minor project I've been putting off: Rebuilding the car's 28-year-old audio system. While it performed well for 15-20 years, a mixture of age, heat, moisture, etc eventually caught up to it.

System goals: 1) Install a system powerful enough to be enjoyed with the top on or off; 2) maintain/improve "period correct" appearance with no head unit and, if possible, no visible speakers; 3) minimize weight; 4) avoid or minimize additional holes/etc.

I'm going into this with the understanding that it's entirely possible the exercise will be futile with a 2.2-liter flat six, but I have been collecting the parts over time and figure it's worth a shot. Some of this stuff has been sitting for years and thus may not be available anymore—but plenty of alternatives are.

Old system components:
Tape cassette head unit Smartphone flopping around on seat > EQ
Pyle graphic EQ turned on/off by factory rear defrost switch
Pioneer fan-cooled amplifier (~1991)
Boston Acoustics four-speaker set in doors (~1991)
Pioneer ducted bass wedge in passenger footwell

New system components:
Smartphone with a proper mount > EQ
Blaupunkt five-channel parametric EQ
JL five-channel amplifier
JL six-speaker set for factory speaker enclosures and door
?? subwoofer in passenger footwell (prepare for now, add later)

Fair warning: This thread may proceed at a glacial pace, as midlife plus a small business means my days in the garage are fairly rare in this chapter. I'm also figuring this out as I go, and will use this thread as a journal and a place to share ideas.

[IronHillRestorations]

Put some surface mount tweeters on either side on the top of the dash, firing at the windshield, you'll get all the highs you need

[horizontally-opposed]

Put some surface mount tweeters on either side on the top of the dash, firing at the windshield, you'll get all the highs you need

Violates goal of "invisible," and maintaining a period interior. (IMG:style_emoticons/default/shades.gif)

Also, was surprised to see JL not only recommend against the high-mount tweeters used by most OEMs, but to specifically recommend locating the tweeters and mids exactly where Porsche chose to mount speakers in the 914.

WOW! What a meticulous installation.

Then all I could think of was my step father, who was a "Hi-Fi" audiophile all the way back from the early 60's; and how he thought everyone should just speak up and quit mumbling (IMG:style_emoticons/default/biggrin.gif) "Whaaat???"

Yeah, that one is "a little" over the top. (IMG:style_emoticons/default/wacko.gif)

Then again, let's be honest: None of us with a flat six behind our heads are doing our ears any favors... (IMG:style_emoticons/default/wink.gif)

[914forme]

Also, was surprised to see JL not only recommend against the high-mount tweeters used by most OEMs, but to specifically recommend locating the tweeters and mids exactly where Porsche chose to mount speakers in the 914.

Not surprised at all with out a proper dsp you can not get sound staging correct. So placing the speakers down low put the two traditional sound locations as close to the same distance to the drivers ears as can be in a car interior. Simple math, gets the sounds waves to your ears as close to possible, minus all the reflection found in the cabin.

Higher end builds in competition world you use DSP and movable tweeters to get the tweeters pointed right to the judges or your ears. I have even seen tweeters with a laser "sights" on it to get them right on target.

As of today I would just go with an amp with a dsp and build the system how ever you can, then get a good set of ears to help you setup the sound stage how you want it to sound. Sony has one, but you can go crazy and spend $1000s on a DSP AMP or A separate DSP, and separate amps to drive what you need driving.