Does my power of receiver match the power of the speaker needed?

2021-01-08 01:56:11

On the jamo website, I see S809 has Power Handling 120w/240w with impedance 8 ohm. Is that the power needed per channel? If so, I see most receivers under $1000 will have RMA output below 120w per channel. Like "Pioneer VSX-LX304" and "Yamaha RX-A2A" both have a price tag of around $800, but both receivers only rated output power of 100 W (8 ohms, 0.06% THD) (20Hz-20kHz, 2-ch driven) what is smaller than 120W what this S809 need. Does that mean even an $800 receiver will not be powerful enough to push a $350 speaker? That doesn't make sense to me.


Here are the products and spec I mentioned above:
https://www.jamo.com/products/s-809#manuals
https://www.adorama.com/pivsxlx304.html
https://www.adorama.com/yhrxa2abl.html
https://amzn.to/356tnK5

Re: Does my power of receiver match the power of the speaker needed?

Reply #1 – 2021-01-08 03:57:56

The power rating of a speaker isn't what it "needs".   It's the recommended maximum amplifier power.    A speaker rated for 120W is supposed to be "safe" with an amplifier playing normal program material and hitting 120W on the peaks.     The specs are a little fuzzy because the peak-to-average ratio isn't nailed down.     (There was an IEC spec but I don't know if it's used anymore and I never see it referenced in consumer speaker specs.)

There is also a sensitivity spec which for your speaker says 90dB @ 2.83V and 1 meter.    2.83V into 8 Ohms is 1 Watt so you can get pretty loud with only 1W.    Double the power is +3dB and 10 times the power is +10dB so you can get 100dB with 10W or 110dB with 100W.     With 120W you'd be less than 111dB, so not significantly louder than 100W.

I ASSUME "120W/240W" means 240W per pair...     Amplifiers are rated per channel so you can ignore the 240W spec.

Re: Does my power of receiver match the power of the speaker needed?

Reply #2 – 2021-01-08 10:30:54

Important thing first: if Jamo is what Jamo was back in the day, these can play loud enough music for a typical living room with a typical receiver.

* As DVDdoug writes, speaker rating indicates the maximum power handling capacity. Conventional wisdom says that if you want to use a 150 W amp on 120 W rated speakers, it means you cannot turn the knob all the way up.
* That is highly misleading though: without knowing the input signal, you cannot really infer output wattage from looking at the volume knob. And indeed if you use a smaller amp but drive it into clipping, it is easier to damage the speakers.

* As for the "240", I suspect that Jamo still rates their speakers to mean it is fitting for an amplifier up to 120 W RMS / 240 W peak.