# Should I Bi Amp or use a separate amp??

kliewerville
Posts:

**7**
Hey Guys.....so i recently bought a new receiver pioneer vsx934 but it pushes about half the power my old yamaha pushed.....ive never needed an amp but am looking into 1. Now my towers are 8ohm and bookshelfs are 6 ohm in which this reciever pushes twice as much on 6 ohm so all i need ampd is my towers. Can i run the amp to one set of plugs on my Signature S55's and the other set just to my reciever? Trying to figure out exactly what i need to get to make this thing atleast get 150w p front channel. Thanks.

## Answers

25,3371) 'half the power' = 3 dB less.

2)

'twice as much on 6 ohm'? Really? It's not impossible (i.e., if the amplifier is 'downrated' in terms of its power output into an 8 ohm load vs a 6 ohm load) but it's not likely.3) 'pushes'?

If you want 'at least 150 watts* p front channel' -- I think you're gonna want a 150 watt per channel amplifier.

More to the point, I suppose -- what are you trying to achieve and why do you think "150 watts" per channel is what you need to achieve it?

____________________

* Speaking of

watts-- do you understand the interrelationship between voltage, current, power, and impedance? If you don't, do a little reading on Ohm's Law.This is really important because it helps explain why, when it comes to transducing electrical watts of power into acoustic watts of power (or dB of sound pressure level, which is a related

but not identicalquantity of "loudness"), a basic knowledge of Ohm's Law in its permutations (as shown on the 'wheel' above) illustrates that there's no such thing as a free lunch.For example 2.83 volts into a nominal 8 ohm load is one watt of electrical power. 2.83 volts into a nominal 4 ohm load is

two wattsof electrical power. The difference?Twice as much currenthas to flow through a four-ohm load compared to an eight-ohm load. If a given amplifier cannot deliver the amount of current needed into alow impedanceload compared to a higher impedance load, itcannotdeliver the expected amount ofpowerinto the lower impedance load.25,337What does this mean?

2.83 volts into 8 ohms is 1 watt.

If you feed a signal at 1 watt of power into one of these speakers and measure the sound pressure level

1 meterfrom the speaker, the SPL is supposed to be 90 dB. That ispretty darned loud.OSHA permissible exposure limit to 90 dB SPL is 8 hours.https://www.etymotic.com/downloads/dl/file/id/47/product/307/noise_exposure_explanation_of_osha_and_niosh_safe_exposure_limits_and_the_importance_of_noise_dosimetry.pdf

Move to two meters away, and the SPL drops to 87 dB; four meters, 83 dB, etc.

If you feed 150 watts of signal into the speaker, and measure SPL 1 meter away, it "should" be (nominally) 111.8 dB. This is dangerously loud, with an OSHA permissible exposure limit of less than 15 minutes per day. More than that will, sooner or later, cause irreversible hearing damage.

As an aside: If you have two speakers (stereo), the SPL will increase by 3 dB, because there are 2 total watts going into the 2 speakers and being transduced into sound. 93 dB 1 meter away.

So... it's not really all quite this simple (because the signal of music waveforms isn't at all simple, and amplifiers aren't at all perfect, nor are loudspeakers... and the room environment 'counts', too), but these are sort of the stakes in the sand when it comes to power, impedance, and SPL for these speakers.

72,142There you go. Clear as mud

One foot on audio nirvana and the other in the poor house.7,742Office Rig- Marantz 2252B, Denon 2910, Kenwood KD2070 TT, Polk RTA 12B's/ RTA8t

25,33713,268I agree. Ohm’s law is only relevant for DC circuits.

Lumin X1

Sony XA-5400ES SACD

Pass XP-22 pre, X600.5 amps

Magico S5 MKII Mcast Rose speakers, SPOD spikes

Shunyata Triton v3/Typhon QR on preamp, Denali 2000 (2) on amps

Shunyata Sigma XLR analog ICs, Sigma speaker cables

Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers

Three 20 amp circuits.

725,337That is not correct.

Ohm's law applies to AC as well; resistance is replaced by impedance.

If 'we' treat impedance as a constant, all of the above is true as written. .. but of course impedance

ain'tconstant, so it ain't (as I said).Now, impedance is a complex quantity since it consists of resitance, capacitive reactance and inductive reactance... and that stuff is all really important, too -- and

part of why Amplifier A and Amplifier B may -- ahem --

pushthe same number of watts, but not perform identically into the same load.5,23813,268Thanks for proving my point.

Lumin X1

Sony XA-5400ES SACD

Pass XP-22 pre, X600.5 amps

Magico S5 MKII Mcast Rose speakers, SPOD spikes

Shunyata Triton v3/Typhon QR on preamp, Denali 2000 (2) on amps

Shunyata Sigma XLR analog ICs, Sigma speaker cables

Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers

Three 20 amp circuits.

1,851What's the current, the current, the current, I want the current.

25,337Any time -- it's still all 100% true, complete and correct, for any given value of "Z". I mean, that's how amplifier designers... design.