400W speakers at 8 ohm or 700W at 4 ohm ?

Question

For an amplifier CS2675:

(EIA 1Khz ; 0.1% THD) : 2 X 378 W / 8 ohmi; 2 x 675 W / 4 ohmi; 1 x 1250 W bridege / 8 ohmi
Sensibilitate intrare : 1 V RMS ( pt sarcina de 8 ohmi)
Damping factor : >300 / 8 ohmi
Raspuns in frecventa : 5Hz - 70 Khz ( -3dB)
Impedanta intrare : Balansat 20 Kohmi , Nebalansat 10 Kohmi
Conectori : Intrare : XLR si Jack 6.3 mm
Iesire : SpeakON (neutrik) , Jack 6.3 mm (recomandat numai pt 8 ohmi ) si Conectori surub

what speakers should i use and why? What is the diference between the two sets because the power is allmost bouble, SO IS THE POWER OF THE SOUND (LOUDNESS), which sound louder, which sounds better?
Tell me all i need to know please.
What do you think of the amplifier because i'm about to buy it right away.

Answer 1

Comparing the available watts between 8 ohms and 4 ohms helps evaluate the quality of construction and power supply.

Those are good specifications’ indicating the amplifier has a large power supply. The BEST amplifiers “double down” meaning the available watts into 8 ohms doubles into 4 ohms. The VERY BEST doubles again into 2 ohms.

Typical inexpensive receivers with inadequate power supplies will be rated 80 watts into 8 ohms and 105 into 4 ohms – not even close to doubling.

You could use any speaker you wanted with that amplifier.

Have you listened to Martin Logan or Magnepan panels speakers? I think they are the ‘best’. They are inefficient 4 ohms speakers - that make beautiful music.
That amplifier would be perfect for them.

Martin Logan and Magnepan speakers are based on different technologies but both sound very different to paper cone speakers

Martin Logan electrostatic speakers are easier to find. They can be found at independent audio solons and Magnolia stores. If used speakers are acceptable my favorite speaker under $2500 is the discontinued Aerius.

Magnepan’s are available only at independent audio solons and much harder to find. Magnepan has a web only special on their least expensive speaker – a 60 day money back guarantee and 100% credit toward better models for one year. Personally, I would travel to the closest store and listen prior to purchasing.

Once you’ve heard these speakers you’ll never be satisfied with box speakers and paper cones again.

Good Luck and Have Fun.

Answer 2

Yes, the 4 ohm 'speakers will be a little louder, but not very much.

(It takes a 10 times increase in power to give a doubling of perceived volume.)

The only difference which you might notice, if you are a critical listener, is that peaks will be reproduced a little more cleanly. But this depends on the type of music you listen to and whether or not you listen at a realistic volume in the first place. If you listen at unnaturally high volumes then you will be blissfully unaware of the subtle difference.