why 2 ohm in front and 4 ohm in rear?
03-03-11, 10:53 AM
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why 2 ohm in front and 4 ohm in rear?
Greetings. I recently replaced the stock front component speakers in my '97 LS400 with Infinity 5030cs (2 ohm). The improvement was noticeable- much less "harsh" sounding than the stock speakers. Working under the assumption that the entire system was 2 ohm, I ordered some Infinity 5032cf two-way speakers (2 ohm) for the rear doors. Popped off the rear door panels to find that the stock speakers back there are 4 ohm. What the hell? I went ahead and put in the new Infinitys- sounds good so far from what I can tell. Should I have put 4-ohm speakers in the rear? Are there any negative implications to what I did? Thanks.
03-03-11, 12:52 PM
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Did your '97 come with Nakamichi stereo?
03-03-11, 01:22 PM
#3
Using the incorrect impedance speakers can damage the amplifier, 2 Ohm speakers will draw twice the current (Amps) of 4 Ohms which can overheat the output devices causing failure.
03-03-11, 04:08 PM
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Just found this on the Infinity website re: the 5032cf:
"True Four Ohms— All Reference speakers feature two ohm voice coils. Original factory-installed speaker wiring in many cars is 18-22 gauge. This wire, and heating in the voice coil when power is applied, increase the impedance “seen” by the amplifier or head unit. The impedance of Reference Speakers has been adjusted to compensate for this increase and can be safely driven by any head unit."
"True Four Ohms— All Reference speakers feature two ohm voice coils. Original factory-installed speaker wiring in many cars is 18-22 gauge. This wire, and heating in the voice coil when power is applied, increase the impedance “seen” by the amplifier or head unit. The impedance of Reference Speakers has been adjusted to compensate for this increase and can be safely driven by any head unit."
Last edited by mathius; 03-03-11 at 04:13 PM.
03-03-11, 06:48 PM
#6
Impedance in any speaker varies with frequency. So the impedance will be lower at lower frequencies and increase with higher frequencies. For instance, the 2 ohm speakers you installed may be 2 ohms at 100 hz but rise to 6 ohms at 5khz. Audio typically varies in the range of 50 hz to 20k hz. The real issue is one of efficiency. When you match the load impedance(speaker) to the source impedance(amplifier), you get the maximum amount of power transfer...ie: sound;
The 2 ohms will work. They just might not be as efficient as the 4 ohm especially at lower frequencies. If you are in the habit of running the volume on the high side with a lot of bass, you may heat the output amplifier a bit more at lower frequencies. However, the amp should have an output limiting circuit which would keep it from burning out. If you run the volume in the < half way level most of the time, you should be fine with the 2 ohm speakers.
The 2 ohms will work. They just might not be as efficient as the 4 ohm especially at lower frequencies. If you are in the habit of running the volume on the high side with a lot of bass, you may heat the output amplifier a bit more at lower frequencies. However, the amp should have an output limiting circuit which would keep it from burning out. If you run the volume in the < half way level most of the time, you should be fine with the 2 ohm speakers.
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BananaGS
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