Please help impedance

[Remigiusz Olejniczak]

Hi. I'm from Poland, sorry if there's already a thread like this. Unfortunately I don't know the language and that makes it difficult to search the forum. Please help, there's a lack of information in Poland and the car audio zone is practically non-existent.

Will this amplifier handle these speakers?

Soundigital 800.4 EVO-6
Technical data
Power @ 4Ω: 4 x 132 W RMS
Power @ 2Ω: 4 x 200 W RMS
Power @ 4Ω: 2 x 400W
Power @ 2Ω: N/A
Frequency response (-3dB): - 8Hz ~ 20kHz
Low pass filter (12dB/octave): - 80Hz
High pass filter (12dB/octave): - 80Hz
Voltage range: - 9V ~ 16V
S/N ratio: - 93 dB
Input sensitivity (RCA): - 0.2 V ~ 2 V
Current consumption (music): - 39A
Current consumption (max.): - 78.7A
Efficiency: - 80%
Damping factor (@nominal impedance 100Hz): - 200
Power cord: - 10 mm² (7 AWG)
Speaker wire: - 2 x 2.5 mm² (13 AWG)
Recommended fuse (music): - 40A
Recommended battery (minimum): - 40Ah

Front speakers:
Audio system R200EM
Rated power - 2x125W RMS
Efficiency up to 94 dB (2.83 V/1 m)
Coil impedance - 3 Ohm (improved value, ideal and safe for radios with 4 Ohm output)
Mounting hole diameter 178mm
Mounting depth only 68 mm
Bandwidth: 35Hz-24kHz

Rear speakers:
SHX-6C Tour
Woofer diameter: 165 mm (6.5 inches)
RMS power: 90 W
Maximum power: 250 W
Impedance: 3 ohms
Frequency response: 50 - 20,000 Hz
Efficiency (1W/1m): 92 dB
Woofer magnet: 12.5 ounces
Mounting depth: 60 mm

I would like to squeeze 95% of their capabilities out of these speakers.

How is it, 3ohm speakers for a stable amplifier in 2ohm and 4ohm, will it play? There is no information about 3ohm speakers for amplifiers anywhere, at least I haven't found it, and I regularly look for information. I know that the speaker impedance cannot be lower than the stable impedance of the amplifier and can be higher, but then the amplifier has higher resistance and is less effective (it loses power). I am asking for advice from people who have knowledge on this subject. Best regards

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[1aespinoza Premium Member]

I know that the speaker impedance cannot be lower than the stable impedance of the amplifier and can be higher,

Exactly. Lowest impedance is 2 Ohms per channel, so 3 Ohms is ok.

but then the amplifier has higher resistance and is less effective (it loses power).

Yes, power drops as impedance rises but your speaker's impedance is lower. In your case, the RMS output per channel is 132w @4 Ohms, so at 3 Ohms it will be ~35w more (halfway point between 132w @4 Ohms and 200w @2 Ohms).That is plenty for the 125w and 90w RMS of each speaker.

 

[Jimi77 Premium Member]

As @1aespinoza said, 3 ohms will be fine and you'll get ~170wrms per channel.

 

[Remigiusz Olejniczak]

Thank you for clearing up my doubts. Could you recommend an amplifier for these speakers or express your opinion on the amplifier provided?

 

[1aespinoza Premium Member]

Thank you for clearing up my doubts. Could you recommend an amplifier for these speakers or express your opinion on the amplifier provided?

Soundigital is well regarded stateside so I would stick with it.
As for the speakers, I have never heard them. The fact that they are 3 Ohms probably means they are designed to replace OEM speakers. At 3 Ohms they would "extract" more power out of the factory unit without overtaxing it.