kangaroo
Member
Posts: 175
Reg: 11-04-06
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05-29-12 08:38 PM - Post#2231340
I have a question for some 6x9's I need to purchase for my truck.
I am using this head unit, CD receiver with built-in MOSFET amplifier (14 watts RMS CEA-2006/50 peak x 4 channels)
http://www.crutchfield.com/S-9SuFi4c...ml#details-...
I am also using these front speakers, RMS Power Handling (Watts): 15, 4 ohm
http://www.newegg.com/Product/Produc...9SIA0ZA08T9...
I do not intend to add any amplifiers but dont know how OHMs plays into my system. Dont know if I should be looking for 2,4,etc ohms speakers. How much watts should I look for with this system also? I usually leave the radio on for about 1 hour with no huge drain on the battery and would like to still do the same.
Thanks
edit: what could I do with a small amp like 50 dollars or less on the amp?
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 CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 700
Loc: Salt Lake City
Reg: 06-20-09
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06-28-12 08:38 PM - Post#2242439
In response to kangaroo
Hey, 'Roo.
Here's the lowdown on power, speaker impedance, and the like.
First, let's get an understanding of your amplifier. It's a 14W amplifier. Ignore what the peak says. You're not going to get intelligible sound at peak unless you're going for stadium class power, which you're not. With that in mind, the power rating is based on a specific load (OHMS). The amplifier maker has to declare what the connected load was to generate the power rating.
The ideal thing is to match the speaker impedance(ohms) to the amplifier's rated RMS power.
Let's say for discussion that the amp was rated at a 4 ohm load. Then, you're going to be fine with the front speakers you have to a point. Do not expect to drive them too hard without getting distortion.
As for the 6x9's, just match them to the amplifier's impedance spec at the listed power and you'll be fine. Next, you'll want to add capactiy in the power handling department. Speakers that are only rated to handle the RMS power of a given amplifier will underperform. Period. A 15W speaker will not handle the intermittent spikes (peak) that naturally occur in musical selections. In order to counteract the distortion monster, you will want to get speakers at least as heavy as the peak output power. Bottom line for you, get some 50W minimum power speakers with the same impedance rating as your head unit.
Now to put closure on the impedance topic for other readers:
If you match your amplifier with speakers the same impedance as the spec, you'll get maximum performance. Going with lower impedance can put your amp at risk of overload under heavy use. Using a higher impedance speaker will leave you wanting more.
Greg
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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justjohn
Silver Supporting Member
Posts: 44
Loc: Piedmont, SC
Reg: 06-23-12
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07-09-12 10:30 AM - Post#2246128
In response to CowboyTrukr
A 4 Ohm speaker is the standard for cars. 8 Ohms is the standard for home speakers.
Almost anything you buy for your car with a built in amp will be rated for a 4 Ohm load. That's what you should be shopping for.
You will see other values out there - most often subwoofers because they are wired in series, which will change the Ohm load at the amp. Only important if you have a high end amp that will not overheat driving a, for instance, 2 Ohm load. This will impact the power output of the amp but is likely not something you are worrying about for your car.
If you add a smaller amp, you will add some complexity but you will be paid back in sound quality.
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 Jim.Biron
"6th Year" Platinum Supporting Member
Posts: 2290
Age: 62
Loc: Saugerties, NY
Reg: 04-10-08
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03-04-13 08:50 AM - Post#2322858
In response to justjohn
A 4 Ohm speaker is the standard for cars. 8 Ohms is the standard for home speakers.
Almost anything you buy for your car with a built in amp will be rated for a 4 Ohm load. That's what you should be shopping for.
You will see other values out there - most often subwoofers because they are wired in series, which will change the Ohm load at the amp. Only important if you have a high end amp that will not overheat driving a, for instance, 2 Ohm load. This will impact the power output of the amp but is likely not something you are worrying about for your car.
If you add a smaller amp, you will add some complexity but you will be paid back in sound quality.
I don't know squat when it comes to this stuff.
Here's a question... Suppose you have an 8 ohm radio and have a 10 ohm speaker. What's the drawback on that? How about a 10 ohm speaker with a 4 ohm radio.
I thought I'd add that the radio in question (vintage 1966 Motorola for my 66 Impala) Says use 8 ohm speaker. I'm just confused as to what to do. AND... are the std AM radios of the 1966 vintage all 4 ohm rated?
All is see is after market speakers with dual coils for the newer stereo radios. I'm looking for something I can use with my 66 mono setup.
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CowboyTrukr
"2nd Year" Silver Supporting Member
Posts: 700
Loc: Salt Lake City
Reg: 06-20-09
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03-18-13 07:36 PM - Post#2327568
In response to Jim.Biron
Jim, for the most part, a 10 ohm speaker is going to limit the power output of any radio. It's a function of resistance to current flow. Your stock radio would have been set up for an 8 ohm load. Now one thing you can do is put in a coaxial or triaxial speaker in place of the stock speaker without risk of harm to your radio. They will have two or three speakers in one frame. It's going to be much better than the stock paper cone speaker. There isn't going to be risk of harm to your unit because it probably only has about a 5 or 7 Watt amplifier circuit. Find a speaker that sounds good to you. Be sure to test it on an AM station in the store to give you a feel for what it's going to sound like.
Greg
'94 Silverado K2500 4X4 5.7 5spd Xcab LB
RV cam, Pace Setter Headers, TBI spacer, Flow Tech air cleaner adapter, Hypertech street chip
"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke |
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