New system December 19, 2012, 06:48:31 PM The Premium Sound System in my 88 Sport has done its job well for 25 years, but it finally gave up. The dash 3.5" speakers are dead, the rear 6x8s are cheap replacements for the originals that blew out while I had an aftermarket CD player pumping through the rear amp. I think the original head unit is OK, but the casette squeaks and who needs cassettes these days. So, I just ordered a pair of Polk Audio 3.5s, a pair of Rockford-Fosgate 6x8s and a Jensen AM/FM/CD/Mpeg/USB head unit that has a SD card slot. I use a similar unit in my RV and it is great... five days of driving music on one chip! So I plan to unplug the rear amp and connect to the alternate connector in the dash that is unused with premium sound. That will feed the speakers direct from the head unit, I won't use the factory amp or equalizer (now I have a hole in the dash to put something else in!). The door speakers are original, but still sound good at full volume, so I will probably not replace them until I listen to the new system. I know, it's not a thumper with a trunk full of speakers and amps, but it should sound good again. Quote Selected
New system Reply #1 – December 20, 2012, 06:25:47 PM I would recommend not using the 22 gauge factory wiring. Get some decent 16 gauge aftermarket speaker wire and run it directly from the head unit to the new speakers. You will want to get new door speakers as the factory ones are garbage with respect to what you have bought and the sound quality will suffer if you have any kind of ear for music.Darren Quote Selected
New system Reply #2 – December 20, 2012, 06:40:12 PM Hi Darrenis there a reason for the 16g wiring? i was curious thanx alot Quote Selected
New system Reply #3 – December 21, 2012, 11:10:24 AM Typically most audio stores carry 16ga wire and up so its relatively easy to get and does not cost alot as it is their entry wire. The 22 ga wire in your car is OLD, which means it is most likey starting to break down an oxidize which hampers its ability to work like it did new. I have rewired I don't know how many car stereos where the owner just used the wiring kit that plugs into the factory harness or they hacked up the factory harness and connected the speaker leads off the head unit directly to the harness. The larger diameter wire will allow the power from the head unit to be fully utilized and the speakers will sound much better.Is it more work? Yes. Is it worth it? Yes in my opinion but do what your wallet will let you and if your ears don't care then no worries. I just figure if I am going to spend the money and time on a head unit and nice speakers the least I can do it put $30 worth of wire in the car and make it sound as good as it can. Kind of like building a motor with 400 rwhp and then keeping the stock Fox brakes...works for some people but not me.Just as an example here is a calculation for the losses between 22 ga and 12 ga over a 20 ft distance (think of it as the runs from the head unit to the rear speakers):16 GaKnowns:Power output per channel = 50 watts (most newer head units are now about 50 watts of mosfet power)Speaker wire length = 20Speaker wire gauge = 16Load impedance = 4 ohmsCalculations:Current flow (amps) = 3.54Speaker wire resistance (ohms) = 0.1599Voltage output at speaker terminals on amp (or in this case head unit) = 14.14Voltage drop at full power (due to resistance in speaker wire) = 0.57Voltage at speaker terminals = 13.6Power delivered to speaker = 46.23 watts[COLOR="blue"]Decibel loss (less than 1 dB is inaudible) = 0.34[/COLOR]22 GaKnowns:Power output per channel = 50 watts (most newer head units are now about 50 watts of mosfet power)Speaker wire length = 20 (rear speakers)Speaker wire gauge = 22Load impedance = 4 ohmsCalculations:Current flow (amps) = 3.54Speaker wire resistance (ohms) = 0.6397Voltage output at speaker terminals on amp (or in this case head unit) = 14.14Voltage drop at full power (due to resistance in speaker wire) = 2.26Voltage at speaker terminals = 12.19Power delivered to speaker = 37.16 watts[COLOR="red"]Decibel loss (less than 1 dB is inaudible) = 1.29[/COLOR]Now you can see that the 22 ga wire versus the 16 ga wire causes a loss in power which causes a loss in sound level and quality. This is with new wire and you are dealing with 20+ year old wire. Hopefully you understand what I am talking about now.Darren Quote Selected
New system Reply #4 – December 23, 2012, 05:37:23 AM One thing to think about is the premium sound system being six speakers and the new head unit only allowing for 4 channels. When you wire your front channels (dash and door speakers) there is a way to wire them in series or parallel. One way is better on the head unit but divides the power between the two speakers in each channel (if I am correct, this would be series) the other way will pull much more from the head unit to power the four speakers into the 2 front channels (parallel).I am just saying this because I ran into this in my 88 XR-7 with the premium sound. I ended up running the dash off the front channel of the head unit, doors off the rear channels and an amplifier to run my Polk 6x9's in the rear deck off the rear channel RCA's and recently added another amp to power a subwoofer from the SUB RCA's.In order for me to bypass ALL the premium sound wiring I ran my own wiring for all the speakers for two reasons. 1. like whats been said, the stock wiring is small and old and 2. the premium sound system sends the signal from the stock head unit to the amplifier in the trunk which then runs the speaker wires from there. Lots of length of excessive wire! I made direct runs from the head unit with heavier speaker wire. Quote Selected
New system Reply #5 – December 23, 2012, 10:52:07 AM Beast50 brought up some excellent points! I wired up my 3-1/2" dash speakers a little different as I wanted the fade on the head unit to work correctly as I prefer the majority of the sound to come from the front, just personal preference here. IMO the Premium Sound is junk and was just a gimmick to sell people on. The easy thing to do is install a 99 microfarad capacitor on the positive lead at the 3-1/2" dash speakers. This will cap those speakers to a range of 400 Hz and up which will allow you to run the door speakers and the dash speakers in series. By doing this the door speakers will handle all the mid-bass frequencies at full power from the head unit. This is assuming you can set a crossover frequency in the head unit which most new unit do allow so your range would be something like 80Hz to 400Hz. Wired in series the door speakers and the dash speakers would then split the power in the higher frequencies (400 Hz to 20,000 Hz) which for me is fine as the higher frequencies never need as much power as the lower ones. Here is a good site showing the different frequencies with regards to speaker ohm and capacitor - http://www.carstereo.com/help/Articles.cfm?id=1.Your only other option is separates (6-1/2 or 5-1/4" mid with a separate 3/4" or 1" tweeter) in which you can install the mid in the door and the tweeter in the dash. The separates come with a passive crossover system that is idiot proof in wiring up and you can mount them under one of the front seats or find room under the dash if you have power seats. Lots of purists will tell you that you do not want to run the tweeter 90 off axis from the mid but I have done this countless times and it works like a champ. The one thing is separates typically will definitely need an amp if you buy good ones (MB Quart, Diamond Audio, Boston Acoustics, etc).Anyhow, that is how I have wired them for years and it works out pretty good. Darren Quote Selected
New system Reply #6 – December 30, 2012, 12:58:10 AM The component speakers would be the way to go for the best sound, but may require an amplifier for maximum benefit. 6 1/2" speakers will fit in the doors, but depth can be an issue for window clearance. Tweeters in the dash locations will work, but you'll need to fabricate a bracket to fit. You can also abandon the dash speakers completely and do a custom tweeter install in the little triangular plastic covers at the front corners of the windows. This will eliminate refraction/reflection from the dash grills and windshield,. Some tpuppies of metal behind the covers may be needed. Installing amplifier(s), signal (rca) and power wiring will be a good excuse to replace the stock speaker wiring with something like Monster XP or better. A custom subwoofer box with 10 or 12" woofers can be tucked under the rear deck as long as you remember to keep clear of the trunk tension rods. 6X9's in the rear deck will fit but need a spacer and may also have clearance issues with the rods. If keeping the stock dash speakers, some newer head units have built-in crossovers which would eliminate the need for the caps. I did the separates in the door/triangle cover with an amp and subwoofers in my first cougar, and it looked great and sounded better. I have MB Quart 6 1/2" components that I will be installing with the tweeters in the aforementioned door cover plates. I will post pics when it's done. Quote Selected
A work in progress Reply #7 – February 01, 2013, 06:04:26 PM OK, I have been listening to the new system for a while and reading some good comments and advice here. So I will report and post a photo. The blankoff panel in the equalizer hole is temporary. The Jensen head unit is mounted in the rectangular opening of the trim panel using the standard slide-in mount. The old SONY unit sat flush, but this one sticks out way too far. The manual says it has threaded holes for surface brackets, so I plan to use the hardware from the factory radio and set it back where it belongs. That huge plastic surround should just peek out then. Anyway, looks aside it sounds great. The Polk DB351 speakers fit the dash mounts perfectly. The larger magnets required melting and denting the AC duct on the pass. side and sawing a small corner off the instrument panel mount on the driver side. I used the filter capacitors supplied and it works fine. Lots of high-end sound without the midrange and bass distortion. Of course, now the door speakers sound like . Looking at a pair of Rockford-Fosgate 6 1/2s to go there, because the new R-F P1683 Punch 6x8s in the rear deck put out a frightening amount of bass. In the interest of not blowing them, I want to install a mono powered subwoofer and stick the bass level control in that empty spot on the dash. Thinking one of those tubular units from Pyle would fit. Don't need too much power, and surely 8" is big enough. The Jensen is only rated 18W rms / 60W max and I am using all the stock speaker wires so far with no problem. I plan to use the factory twisted pair from the old amp to feed the LFE output to the powered sub. Any advice or warnings? Remember, I only want to enhance the bass, not set off car alarms. Quote Selected
New system Reply #8 – February 01, 2013, 07:45:52 PM A factory cubbie should bolt in your empty slot and look like stock. Not sure what the bass controller thingy is you talking about, but it could prob fit in there somewhere with the cubbie. Your setup looks really nice in the pics. Quote Selected
New system Reply #9 – February 02, 2013, 12:19:43 AM I have two flipout stereo's and a flipload cd player. I can't use the surround on any of them, and the cd player got moved to the upper slot, and actually won't open in that one. I use usb's on that radio because it doesn't have an antenna either, and a really stiff suspension that doesn't seem to get along with cd's. Quote Selected
New system Reply #10 – February 02, 2013, 01:51:44 AM Quote from: Aerocoupe;405070Calculations:Current flow (amps) = 3.54Speaker wire resistance (ohms) = 0.6397Voltage output at speaker terminals on amp (or in this case head unit) = 14.14Voltage drop at full power (due to resistance in speaker wire) = 2.26Voltage at speaker terminals = 12.19Power delivered to speaker = 37.16 watts[COLOR="red"]Decibel loss (less than 1 dB is inaudible) = 1.29[/COLOR]The problem with this is that the headunits' 50W rating is about as useful as PMPO ratings of the 90's. A typical heaunit is rated ~20-22W RMS max and you shouldn't expect to get "cleanish power" past 3/4 that. Add to that you would only reach that output if you were playing a test tone since you're running next to nothing when listening to music. Only the bass will use the extra power, but the losses wouldn't be noticeable using the thinner wire with a proper connection at both ends.The human ear is generally claimed to pick up "double volume" at closer to 10dB (9W will be about twice as loud as 1W), so even at 50 Watts with your numbers, it isn't discernible, especially since it'd only impact bass just slightly. Speakers with an efficiency rating of 90dB at 1W (8 ohms at 2.73V, 4 ohm aftermarket car speakers are rated at 2W/2.73V) at a distance of 1 meter (close to car environment) are already approaching ear damage territory. My home speakers are around 100dB at 1W.I'm not saying it isn't a good idea to use new wire though. My setup from the trunk uses 12 gauge pure copper. The weight difference for a front stage was minor vs 14/16/18, as was the price, so why not. The general rule is that speaker wire shouldn't exceed some percentage of the voice coils which puts 18 gauge ideal for cars. With a drop in replacement system where there are already wires that can connect the headunit directly to the speakers, there is no reason to recommend someone upgrade the wiring. Hell, many "audiophiles" use Cat5/6 wiring in home systems with 100+W RMS amps with much of that wire being 24-26awg.As for using 6 speakers, people with stock systems should just wire them up in parallel. The resistance in the stock wiring will make the load at the headunit appear closer to 4 ohms when in use, rather than 2 ohms on upgraded wiring when using two speakers in parallel. Dropin replacements aren't sound quality competition builds, so keep it simple.I think you did good Stealth. Quote Selected
New system Reply #11 – February 06, 2013, 08:27:20 AM Seek, thanks for the vote of confidence. I do plan to hook the door speakers up in parallell with the dash speakers using the stock wiring. I am guessing that I won't need a crossover because I have the filter capacitor on the dash speakers and the 6 1/2" door speakers will naturally respond better to midrange. As to the current for the rear speakers, the LFE signal to the sub is very low power. My main concern is that heavy bass pulses may cause the sub amp to momentarily draw more current than the power supply wire can carry. I think that is why the thumper crowd use welder cable for power and stick a battery in the trunk to handle surges. What level of wattage would it take to require extra heavy power feed? I am hoping the power draw on my more modest system will not require such tricks. And I'm the guy who used to carp and gripe about the " trunk full of speakers" when I had to work on a customer's car! Actually had a dude bring his Cadillac to me to see why the rear tires rubbed when sister sat in back. Wheel wells had been hammered in by the stereo shop to make room in the trunk and sister weighed 300#. Thump, thump, thump! Quote Selected
Topic: New system (Read 2917 times)
previous topic - next topic
