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CD-R and Audio Hardware => Audio Hardware => Topic started by: jeff12138 on 2021-01-08 01:56:11

Title: Does my power of receiver match the power of the speaker needed?
Post by: jeff12138 on 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
Title: Re: Does my power of receiver match the power of the speaker needed?
Post by: DVDdoug on 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.
Title: Re: Does my power of receiver match the power of the speaker needed?
Post by: Porcus on 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.
Title: Re: Does my power of receiver match the power of the speaker needed?
Post by: dewdude on 2021-02-15 15:09:45
(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.)

I haven't seen an IEC spec on things since early 80's gear! My Denon for example lists multiple power ratings for different standards. The IEC Power Rating at 4 ohms is half of what the (DIN,UK,U.S.A.) rating is. I'm pretty sure manufacturers use the standard they can get away with that gives them the larger number.  Its like why do antenna manufacturers use dBi (decibels/isotropic), a unit based on theory, rather than dBd (decibels/dipole), a unit based on performance of an actual dipole? Because dBi gives larger numbers.

Anyway...Jamo has been owned by Klipsch since 2005 if that counts for anything. They're not the same company they were but I don't think it hurt them much...other than flipping to Chinese manfacturing.



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