Hello,
Reid again. The Xtant amp was sold out from underneath me. Sounds like that may have been a blessing....
I have an Alpine 7892 HU, and I'll be installing 2 pair of MB Quarts speakers, Reference co-axes for the rear of a 2002 Subaru Outback, and Premium component speakers for the front.
At this point I will not be installing an amp. OK. Call me a weany, but I want to hear if it'll sound "good enough" without the expense and hassle of installing an amp.
Question is. I have a spool of 18 ga wire I'd like to use for the speakers. What do you folks reccomend for where and how to connect with the wiring harness. When I bought the HU, the saleman suggested that instead of cutting off the car's factory radio wiring harness that I buy two adapters: one from the factory harness to a universal adapter; and the other, from the uni adapter to the HU. It works fine, but if I need to rewire the factory wires to the the speakers (or can I use it? looks kinda thin...) what's the best thing to do? I was figuring to cut the speaker wires between the HU and the adapter, so I wouldn't damage the stock harness (it's still under warranty), and just soldier the wire from there.
Any other suggestion? I also welcome recommendations for a 4 channel amp, if I decide to install one, that wouldn't be expnesive used (read: $100-$150). If anyone is selling an amp, let me know. It would be much easier if I'm going to install the speakers to do the amp at the same time.
Thanks,
Reid
Replies (3)
Swez on 05/21/2003 17:31:28
You got it... why do the wiring twice! Besides, if the HU us rated 40-50 watts x4, what you are really getting is about 50% of that power RMS... roughly 20 watts RMS @ 4 ohms, is the norm.
As for an amp, a lot of us are now using value priced amps from US Acoustics. Very well made, nice features and plenty of power to make you grin from ear to ear.... GRIN
Look here: http://www.thezeb.com/caraudio/us_acoustics.html
1. USX4065 Amplifier - 65x4 @ 4ohm - 320 watts RMS total $122.99
2. USX4085 Amplifier - 85x4 @ 4ohm - 480 watts RMS total
$172.99!
As for speaker wiring, here's a chart to reference:
12 awg 20.84 amps 172 watts
13 awg 16.54 amps 137 watts
14 awg 13.13 amps 109 watts
15 awg 10.42 amps 86 watts
16 awg 8.27 amps 69 watts
17 awg 6.56 amps 54 watts
18 awg 5.21 amps 43 watts
Depending on the amp you choose and the length of wire to each speaker, #14/16 are your best bets. Most stock wire is 16/18 gage.
If you bridge the rear channels to power a sub, go with #12 wire to be on the safe side and get all the power from the amp. to your sub or #14 for rear channel MBQ's. Depending on the amp you choose, use the right gage speaker wire per chart.
Finally, you may find it best to simply unplug the HU speaker harness connector and then run your speaker wires to the front, hiding them under the carpet trim panels. Just make sure both wires to front/rear speakers are the same length over all. You may have to coil the short line and hide it as best you can.
Swez
PS The #18 you have now is pretty small and I would suggest not using it here. Either take it back to get the proper size or hang on to same for other projects later.
PSS The difference in output SPL between the -4065 and -4085 is only ~ 1.0 dB more SPL... hense, the -4065, is your best value.
Reid on 05/21/2003 19:54:26
So, if I've got your correctly, it looks like I could use the original wiring, since the head unit is only putting out around 20 watts, and assuming the factory wire is 18 gage, if I'm installing without an additional amp.
But if I do get an amp, then I should re-wire with 14/16 awg.
The HU doesn't have a seperate harness for the speakers, it's all together with the power and ground cords that goes to the universal adapter. I guess if I cut the 8 wires for the speakers, the adapter isn't really doing that much, expect for the power, ground, and memory. Maybe I should just wire directly without the adapters.
Why should the wires be the same length? I thought I should keep the as short as possible?
So the 18 awg is too small? For what its worth, I use the wire to run speakers in the kitchen from the living room receiver. I used about 50 ft of the 18 awg, and it sounds fine. What's the problem with the car?
Thanks?
Reid
Swez on 05/22/2003 05:57:46
Asking some good questions Reid...
Smaller gage speaker wires deliver less signal power to the speakers. They have more resistance per linear foot and the more resistance in the link between speakers and amp, means a loss of power. Also, as line length get longer and inductive resistance factors increase, loss of high frequency output is the general outcome.
Sure, you can run 50' of #18 gage wire in your Home Theater system if the power is low to the rear channels. But if you ran 16/14, more power to these speakers and better high frequency performance would be noted. Try it and see! I used #12 for my rear channels and all was very good at ~40 feet.
About running the same lengths of line to each stage of speakers give the same load resistance to each amplifier/speaker in that part of your sound stage. Sure you can make up te differences by gain adjustments, or fade/balance on the HU... but quality installers try to level the playing field as much as possible by using same length wires to each matching speaker in that field. But yes, keeping the wires as short as possible, is a good rule to follow.
About using HU power and stock wires... should be fine as you are well under the 40+ watts (RMS) limits of that wire. But... if you add an amplifier, the wire gage needed to carry that extra power should be adequate per the wiring chart. Ever try to plug a high current device (1500 watt hair drier) into a small gage extension wire? What happends???? The wire gets hot! Sure, the hair dryer is only in use for 10 minutes or so, but feel the heat build up in that small gage extension cord. If you ran the hair drier for a few hours, the wire jacket insultion could eventually melt, cause a short or catch on fire.
Don't want that to happen in your car right?
This is mostly true of power wire gage selection when wiring amplifiers... but high power sub systems have caused problems when inadequate wire gage was used. I have read of several situations where a guy use inadequate wiring, his wires shorted, smoked the amp and damaged expensive subs too. Just trying to save you the grief of learning the hard way.
Finally, if you do elect to add an amp later... (And I will bet a large cup of coffee on it, you will) you can just snip the speaker wires off the harness and use crimp connectors from the amp wire feeds to your stock speakers. These wires are pretty short, so #18 gage to each stock speaker location is not a major issue. Just be sure to cap off the remaining HU speaker wires so they do not short out. Butt type crimp connectors will do fine. Just be sure you allow enough pigtail wire off the harness, to make the job easier and not a bunch of bulky connectors to interfere with HU install/uninstall later.
Hope that helps,
Swez
Reid again. The Xtant amp was sold out from underneath me. Sounds like that may have been a blessing....
I have an Alpine 7892 HU, and I'll be installing 2 pair of MB Quarts speakers, Reference co-axes for the rear of a 2002 Subaru Outback, and Premium component speakers for the front.
At this point I will not be installing an amp. OK. Call me a weany, but I want to hear if it'll sound "good enough" without the expense and hassle of installing an amp.
Question is. I have a spool of 18 ga wire I'd like to use for the speakers. What do you folks reccomend for where and how to connect with the wiring harness. When I bought the HU, the saleman suggested that instead of cutting off the car's factory radio wiring harness that I buy two adapters: one from the factory harness to a universal adapter; and the other, from the uni adapter to the HU. It works fine, but if I need to rewire the factory wires to the the speakers (or can I use it? looks kinda thin...) what's the best thing to do? I was figuring to cut the speaker wires between the HU and the adapter, so I wouldn't damage the stock harness (it's still under warranty), and just soldier the wire from there.
Any other suggestion? I also welcome recommendations for a 4 channel amp, if I decide to install one, that wouldn't be expnesive used (read: $100-$150). If anyone is selling an amp, let me know. It would be much easier if I'm going to install the speakers to do the amp at the same time.
Thanks,
Reid
Replies (3)
Swez on 05/21/2003 17:31:28
You got it... why do the wiring twice! Besides, if the HU us rated 40-50 watts x4, what you are really getting is about 50% of that power RMS... roughly 20 watts RMS @ 4 ohms, is the norm.
As for an amp, a lot of us are now using value priced amps from US Acoustics. Very well made, nice features and plenty of power to make you grin from ear to ear.... GRIN
Look here: http://www.thezeb.com/caraudio/us_acoustics.html
1. USX4065 Amplifier - 65x4 @ 4ohm - 320 watts RMS total $122.99
2. USX4085 Amplifier - 85x4 @ 4ohm - 480 watts RMS total
$172.99!
As for speaker wiring, here's a chart to reference:
12 awg 20.84 amps 172 watts
13 awg 16.54 amps 137 watts
14 awg 13.13 amps 109 watts
15 awg 10.42 amps 86 watts
16 awg 8.27 amps 69 watts
17 awg 6.56 amps 54 watts
18 awg 5.21 amps 43 watts
Depending on the amp you choose and the length of wire to each speaker, #14/16 are your best bets. Most stock wire is 16/18 gage.
If you bridge the rear channels to power a sub, go with #12 wire to be on the safe side and get all the power from the amp. to your sub or #14 for rear channel MBQ's. Depending on the amp you choose, use the right gage speaker wire per chart.
Finally, you may find it best to simply unplug the HU speaker harness connector and then run your speaker wires to the front, hiding them under the carpet trim panels. Just make sure both wires to front/rear speakers are the same length over all. You may have to coil the short line and hide it as best you can.
Swez
PS The #18 you have now is pretty small and I would suggest not using it here. Either take it back to get the proper size or hang on to same for other projects later.
PSS The difference in output SPL between the -4065 and -4085 is only ~ 1.0 dB more SPL... hense, the -4065, is your best value.
Reid on 05/21/2003 19:54:26
So, if I've got your correctly, it looks like I could use the original wiring, since the head unit is only putting out around 20 watts, and assuming the factory wire is 18 gage, if I'm installing without an additional amp.
But if I do get an amp, then I should re-wire with 14/16 awg.
The HU doesn't have a seperate harness for the speakers, it's all together with the power and ground cords that goes to the universal adapter. I guess if I cut the 8 wires for the speakers, the adapter isn't really doing that much, expect for the power, ground, and memory. Maybe I should just wire directly without the adapters.
Why should the wires be the same length? I thought I should keep the as short as possible?
So the 18 awg is too small? For what its worth, I use the wire to run speakers in the kitchen from the living room receiver. I used about 50 ft of the 18 awg, and it sounds fine. What's the problem with the car?
Thanks?
Reid
Swez on 05/22/2003 05:57:46
Asking some good questions Reid...
Smaller gage speaker wires deliver less signal power to the speakers. They have more resistance per linear foot and the more resistance in the link between speakers and amp, means a loss of power. Also, as line length get longer and inductive resistance factors increase, loss of high frequency output is the general outcome.
Sure, you can run 50' of #18 gage wire in your Home Theater system if the power is low to the rear channels. But if you ran 16/14, more power to these speakers and better high frequency performance would be noted. Try it and see! I used #12 for my rear channels and all was very good at ~40 feet.
About running the same lengths of line to each stage of speakers give the same load resistance to each amplifier/speaker in that part of your sound stage. Sure you can make up te differences by gain adjustments, or fade/balance on the HU... but quality installers try to level the playing field as much as possible by using same length wires to each matching speaker in that field. But yes, keeping the wires as short as possible, is a good rule to follow.
About using HU power and stock wires... should be fine as you are well under the 40+ watts (RMS) limits of that wire. But... if you add an amplifier, the wire gage needed to carry that extra power should be adequate per the wiring chart. Ever try to plug a high current device (1500 watt hair drier) into a small gage extension wire? What happends???? The wire gets hot! Sure, the hair dryer is only in use for 10 minutes or so, but feel the heat build up in that small gage extension cord. If you ran the hair drier for a few hours, the wire jacket insultion could eventually melt, cause a short or catch on fire.
Don't want that to happen in your car right?
This is mostly true of power wire gage selection when wiring amplifiers... but high power sub systems have caused problems when inadequate wire gage was used. I have read of several situations where a guy use inadequate wiring, his wires shorted, smoked the amp and damaged expensive subs too. Just trying to save you the grief of learning the hard way.
Finally, if you do elect to add an amp later... (And I will bet a large cup of coffee on it, you will) you can just snip the speaker wires off the harness and use crimp connectors from the amp wire feeds to your stock speakers. These wires are pretty short, so #18 gage to each stock speaker location is not a major issue. Just be sure to cap off the remaining HU speaker wires so they do not short out. Butt type crimp connectors will do fine. Just be sure you allow enough pigtail wire off the harness, to make the job easier and not a bunch of bulky connectors to interfere with HU install/uninstall later.
Hope that helps,
Swez
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