Home » Public Forums » GMCnet » Stereo rewire...
| Stereo rewire... [message #285344] |
Tue, 18 August 2015 22:21  |
quadracerx1
Messages: 207
Registered: April 2013
Location: Puyallup, Washington
Karma: 1
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Senior Member |
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Hey guys,
Back to work on the GMC, in the planning stages of adding additional 110, 12 Volt and stereo wiring while I have the interior out...
Is it possible to use Bose Acusti-mas home speakers with a car stereo head unit?
I only ask because I don't really want to limit my speaker choices in the stock location and it seems pointless to have two sets of speakers....
Either that or I will put a real Home receiver with the Bose speakers and buy a second set of car speakers to go in the stock locations...
Thanks..
Steve
75 26' GMC Glenbrook
Puyallup, Washington
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| Re: Stereo rewire... [message #285346 is a reply to message #285344] |
Tue, 18 August 2015 22:47  |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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quadracerx1 wrote on Tue, 18 August 2015 20:21Hey guys,
Back to work on the GMC, in the planning stages of adding additional 110, 12 Volt and stereo wiring while I have the interior out...
Is it possible to use Bose Acusti-mas home speakers with a car stereo head unit?
I only ask because I don't really want to limit my speaker choices in the stock location and it seems pointless to have two sets of speakers....
Either that or I will put a real Home receiver with the Bose speakers and buy a second set of car speakers to go in the stock locations...
Thanks..
Steve
Call Jim Bounds at the GMC Co-op. He is an expert on this.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: Stereo rewire... [message #285354 is a reply to message #285344] |
Wed, 19 August 2015 07:31 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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You can use pretty much any speakers you want. You're going to have to run new speaker wires anyway unless you use the original radio which grounded one side of the speakers. Just be sure you mount whatever solidly. Note that if you do use the original radio, you must use GM or equal speakers, they're a weird impedance and necessary for that radio to work properly.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Stereo rewire... [message #285364 is a reply to message #285354] |
Wed, 19 August 2015 08:44 |
Justin Brady
Messages: 769
Registered: April 2015
Location: Bell Buckle, TN
Karma: 11
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The speaker doesn't matter.
The impedance of the speaker does.
Most car stereos are made to run speakers at 4 ohms. Most home speakers are 6 ohm.
As long as the Ohm's are higher than 4 you should be fine. So your 6 ohm speakers will run fine off a car head unit, they may not be as loud as they would be on a home system that is designed for a 6 ohm load.
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455
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| Re: [GMCnet] Stereo rewire... [message #285365 is a reply to message #285364] |
Wed, 19 August 2015 08:47 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Pay attention to the grounding. Modern units don’t like the ground and the negative lead being tied to the chassis.
HTH
Dolph
DE N8JPC
Wheeling, West Virginia
1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010
“The Aluminum and Fiberglass Mistress"
> On Aug 19, 2015, at 9:44 AM, Justin Brady wrote:
>
> The speaker doesn't matter.
> The impedance of the speaker does.
> Most car stereos are made to run speakers at 4 ohms. Most home speakers are 6 ohm.
> As long as the Ohm's are higher than 4 you should be fine. So your 6 ohm speakers will run fine off a car head unit, they may not be as loud as they
> would be on a home system that is designed for a 6 ohm load.
>
>
> --
> Justin Brady
> 1976 Palm Beach 455
>
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| Re: Stereo rewire... [message #285379 is a reply to message #285344] |
Wed, 19 August 2015 11:02 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Actually, the majority of speaker systems for home use are 8 ohm. But as noted, all you'll lose is some power. Also as noted >don't< let either speaker wire become grounded. This will do Bad Things to some amplifiers. The auto stereo manufacturers like 4 ohm speakers because they can build their amplifiers somewhat more cheaply than if they have to match an 8 ohm load.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
[Updated on: Wed, 19 August 2015 11:02] Report message to a moderator |
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| Re: Stereo rewire... [message #285381 is a reply to message #285379] |
Wed, 19 August 2015 11:05 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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You can always drive the speakers with Bluetooth, if your radio supports it. Thinking in terms of the rear speaker set. Disassemble a Bluetooth Speaker Bar for component parts.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] Stereo rewire... [message #285389 is a reply to message #285379] |
Wed, 19 August 2015 11:25 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Where is all this lower power stuff coming from?
Power (watts) = E squared / Z
Therefore, assuming 10 volts of audio (at 1kHz) into and 8 ohm load
Pw = 100 / 8
Pw = 12.5
The same at 4 ohms:
Pw = 100 / 4
Pw = 25 watts
Most amplifier designs will handle either load without a problem, it’s just a matter of it being difficult to design a loudspeaker at much less than 4 ohms. Poor amplifier designs will not maintain linearity from 4 to 8 to 16 ohms. I’m not taking that into account for this example.
Speakers in parallel cut the impedance in half - two four ohm speakers in parallel equals 2 ohms, and some amplifiers won’t like that.
Finally, if you decide to put your VOM on the speaker, you can’t measure it that way - Impedance is an AC measurement at a given frequency, generally 1kHz in the audio world. Resistance is the resistance of the voice coil wire, and the two are different animals.
Before I get called on the carpet, the formula for measuring AC power is Pw = E squared / Z cosine Theta (which is power factor correction). Again, outside of this discussion.
Dolph
DE N8JPC
Wheeling, West Virginia
1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010
“The Aluminum and Fiberglass Mistress"
> On Aug 19, 2015, at 12:02 PM, Johnny Bridges wrote:
>
> Actually, the mmojority of speaker systems for home use are 8 ohm. But as noted, all you'll lose is some power. Also as noted >don't< let either
> speaker wire become grounded. This will do Bad Things to some amplifiers. The auto stereo manufacturers like 4 ohm speakers because they can built
> their amplifiers somewhat more cheaply than if they have to match an 8 ohm load.
>
> --johnny
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
>
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| Re: [GMCnet] Stereo rewire... [message #285391 is a reply to message #285389] |
Wed, 19 August 2015 12:22 |
Jim at the Co-op
Messages: 291
Registered: May 2014
Location: Orlando Florida
Karma: 2
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If you have the interior out I would run all new wires, makes things easy
and simple. New radios today are stupid cheap to what us old Duffers are
used to and the outputs can handle up to almost a dead short. I'm running
into a 2 ohm load on what we wire with really good results. I use new 3.5"
dual cone spks up top, a pair of 2 way 6.5 spks in the kick panels up front
and cross left & right on them. That way you get imaging content top to
bottom, left to right. Wire in 2 more 6.5 2 ways facing down in the
forward overheads and a pair of 4x10's in the bedroom with those 2 ohms on
the rear channels. Works very well. Less than $200 will get you a 7"
motorized screen, blue tooth, remote, hi power, USB, CD and mini phone
inputs. Stupid cheap... And running a 2 ohm load gets it pretty loud...
On Wed, Aug 19, 2015 at 12:25 PM, Dolph Santorine
wrote:
> Where is all this lower power stuff coming from?
>
> Power (watts) = E squared / Z
>
> Therefore, assuming 10 volts of audio (at 1kHz) into and 8 ohm load
>
> Pw = 100 / 8
>
> Pw = 12.5
>
> The same at 4 ohms:
>
> Pw = 100 / 4
>
> Pw = 25 watts
>
> Most amplifier designs will handle either load without a problem, it’s
> just a matter of it being difficult to design a loudspeaker at much less
> than 4 ohms. Poor amplifier designs will not maintain linearity from 4 to 8
> to 16 ohms. I’m not taking that into account for this example.
>
> Speakers in parallel cut the impedance in half - two four ohm speakers in
> parallel equals 2 ohms, and some amplifiers won’t like that.
>
> Finally, if you decide to put your VOM on the speaker, you can’t measure
> it that way - Impedance is an AC measurement at a given frequency,
> generally 1kHz in the audio world. Resistance is the resistance of the
> voice coil wire, and the two are different animals.
>
> Before I get called on the carpet, the formula for measuring AC power is
> Pw = E squared / Z cosine Theta (which is power factor correction). Again,
> outside of this discussion.
>
> Dolph
>
> DE N8JPC
>
> Wheeling, West Virginia
>
> 1977 26’ ex-PalmBeach
> 1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010
>
> “The Aluminum and Fiberglass Mistress"
>
>
>
>
>
>
>
>
>
>
>> On Aug 19, 2015, at 12:02 PM, Johnny Bridges
> wrote:
>>
>> Actually, the mmojority of speaker systems for home use are 8 ohm. But
> as noted, all you'll lose is some power. Also as noted >don't< let either
>> speaker wire become grounded. This will do Bad Things to some
> amplifiers. The auto stereo manufacturers like 4 ohm speakers because they
> can built
>> their amplifiers somewhat more cheaply than if they have to match an 8
> ohm load.
>>
>> --johnny
>> --
>> '76 23' transmode Norris upfit
>> Braselton, Ga.
>>
>> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: Stereo rewire... [message #285487 is a reply to message #285344] |
Thu, 20 August 2015 19:15 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Dolph shows why a 12 volt supply for the amp section will produce more power into 4 ohms than 8. Higher power requires an inverter in the amp to up the supply voltage. To make this more fun, the speaker load impedance is normally quotes at 1KHz... or if you're old as I am, a thousand cycles. At other frequencies, it is likely to e anything but 8 ohms.
From a practical point though, remember, it is much easier to destroy a loudspeaker with an underpowered amp than with an overpowered one.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: Stereo rewire... [message #285500 is a reply to message #285344] |
Thu, 20 August 2015 21:02 |
zhagrieb
Messages: 676
Registered: August 2009
Location: Portland Oregon
Karma: 0
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Senior Member |
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Bose systems use a separate low frequency "woofer" in order to get the full spectrum of audio. If you use just the little high frequency units you'll loose a major portion of the sound. You probably could connect the small units to a standard car receiver but to use them with the woofer would require AC power and a crossover network to separate the highs and lows. You'd also need a place for the rather large woofer.
Glenn Giere, Portland OR, K7GAG
'73 "Moby the Motorhome" 26'
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| Re: Stereo rewire... [message #285507 is a reply to message #285344] |
Thu, 20 August 2015 22:43 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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The best approach is to put the high frequency speakers up where they're line of sight, and the big woofers somewhere out of the way (there's no directionality with the bass notes anyway - the wavelength is too long for your ears to work out where the sound is coming from). Luckily, most of us have a couch or a dinette base that can serve as a great subwoofer enclosure. I put small monitor speakers up under my front cabinets, and an amp and a couple 8" subwoofers under my rear-facing dinette seat base. The in-dash unit has enough umph to do a good job with the four monitor speakers (
I also wired the cockpit and bedroom speakers in parallel on the "rear channels" but keep the fader set so they're only getting a little of the power, unless we're listening to a book on CD, then I swing it back up to the cockpit speakers.
The system wasn't big bucks, but is more than adequate for anything but cracking the windows... it can certainly sound good at volumes you really wouldn't want to be dealing with inside the coach. There are a host of similar small monitor speakers that can do a good job filling the inside of a coach with plenty of sound, particularly if you also install subwoofer(s), and the sound will be light years ahead of "car speakers" installed in the cockpit or squirreled away out of sight.
Some photos: 
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: Stereo rewire... [message #285508 is a reply to message #285344] |
Thu, 20 August 2015 22:43 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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Senior Member |
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The best approach is to put the high frequency speakers up where they're line of sight, and the big woofers somewhere out of the way (there's no directionality with the bass notes anyway - the wavelength is too long for your ears to work out where the sound is coming from). Luckily, most of us have a couch or a dinette base that can serve as a great subwoofer enclosure. I put small monitor speakers up under my front cabinets, and an amp and a couple 8" subwoofers under my rear-facing dinette seat base. The in-dash unit has enough umph to do a good job with the four monitor speakers (
I also wired the cockpit and bedroom speakers in parallel on the "rear channels" but keep the fader set so they're only getting a little of the power, unless we're listening to a book on CD, then I swing it back up to the cockpit speakers.
The system wasn't big bucks, but is more than adequate for anything but cracking the windows... it can certainly sound good at volumes you really wouldn't want to be dealing with inside the coach. There are a host of similar small monitor speakers that can do a good job filling the inside of a coach with plenty of sound, particularly if you also install subwoofer(s), and the sound will be light years ahead of "car speakers" installed in the cockpit or squirreled away out of sight.
Some photos: http://www.gmcmhphotos.com/photos/electrical/p46286-stereo-installation-in-my.html
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
[Updated on: Thu, 20 August 2015 22:44] Report message to a moderator |
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