Wattage question

N

natpond

Limp Gawd
Joined
Aug 11, 2004
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162
I just ordered an H/K AVR 235 reciever and have just been looking around, and it seems to be a kick ass reciever except most others have much more wattage. now, i dont really know what mattage means per se, but i am led to believe that wattage could equate to volume. i asked a while back if thei reciever would be enough to power the B&W 602s im going to buy and was told a resounding YES. i know this wil be enough to POWER them, but i like loud music... will 50 watts a channel be enough? AHHHH help me, the reciever has already shipped so i cant cancel it.

Nat
 
Have no fears. That should easily be enough to power those speakers to quite loud volumes.
 
Ah, B&W 602, Hope you enjoy them.

To be honest with you, wattage claims are another "shakey" topic. Because there is no "standard" for wattage claims, so they mean very little.

Some do the average power output, while others do the max power output with a time of 0.1 seconds of power...................

Usually with higher end equipment, you start getting into the less gimmiky numbers and more the true power.

When talking about a amp's wattage, it means how much power it can deliver to the speakers. But what the wattage numbers DO NOT tell you, is how the receiver/amp will work for speakers with less then perfect 8ohm resistance, or with quick "bang" music, like a quick bass note.

To break this up even furthur, an ideal amp would provide twice as much "power" to a speaker with a perfect 4 ohm resistance as opposed to a speaker with a perfect 8ohm resistance. The problem is most receivers are not perfect, and some are no where close to the "2 times power for 1/2 the resistance". Because of this, the amp will not be able to supply the "rated" amount of power to speakers with less then 8ohms of resistance (most "8ohm" speakers have dips and peaks at certain frequencies, I know my B&W 601 S3 say they go down as low as 3ohms).

As for the quick music "bang", this is dealing with the storage capacitors in the receiver, which store energy for quick sudden power. If the amp can't store enough energy, then you won't get the true sound out of the speakers.

Also, don't forget (unless you never knew), that for every 3dB change in music, the power required to make that change is doubled.
So, if you have a 500watt amp that produced sound out of the speakers at 100dB, then a 1000watt amp would be able to push that sound to 103dB. Although it seems like there is a big diffrence between 500watts and 1000watts, the noticible diffrence is very small.
Just to give you a sense of what this translates into, most people say that to "double" the perceived sound level, a 10dB increase is necessary. So the diffrence, strictly speaking, between the 500watt amp and 1000watt amp would be very little.

This is where the Sensitivity rattings of your speakers come into play (SPL levels). If you want true loud speakers, your better getting higher sensitivy speakers then a receiver that cliams 70watts as opposed to 35watts.

Just for a quick example:
Speakers A: rated sensitivity at 96dB (@1watt @1meter) with 30watt amp = 111dB SPL max
Speakers B: rated sensitivity at 84dB (@1watt @1meter) with 500watt amp = 111dB SPL max
This is why some speakers will run fine off an amp with 7watts of amplifying power.

Oh, and before I forget, the cheaper receivers/amps start to distort around the mid point for the volume knob. So just because the receiver "says" it can go higher, does'nt mean its going to faithfully reproduce the music.

If you really want to know more, im sure you can find a metric ton of information on the internet, or in a high end audio book.

~Hope this helps
 
wow. i could find a metric ton, but why do that when i just got about 3/4 of a metric ton anyways... hehe. THanks though, that was SUPER helpful, the parts i managed to follow at least. So bottom line is they will get loud with 50 watts of power even though they are rated up to 120.... right?

Nat
 
natpond said:
wow. i could find a metric ton, but why do that when i just got about 3/4 of a metric ton anyways... hehe. THanks though, that was SUPER helpful, the parts i managed to follow at least. So bottom line is they will get loud with 50 watts of power even though they are rated up to 120.... right?

Nat
Click to expand...
:cool:

Yes. The "maximum" (in theory) diffrence between 120watts and 50watts would be about 3.8dB which is'nt too much. Its much more the quality of power comming from the receiver, and how well the receiver/amp holds up to the demends of the music.
Max power output becomes more of an issure with live concert type speakers where very high volumes are needed. (Ide hate to see the energy bill of a live concert).

~Hope this helps
 
yeah, i have an HK avr130 which does 45w, and my front mains are infinity beta 50's that are spec'd at 10-200 watts, and they certainly get loud enough!
 
nice, have my reciever now, its hooked up to my klipsch pro media satellites for the time being as i look for the best price on the 602s. any ideas how to hook the subwoofer up? as this thread has said, i like bass and it really isnt the same without a woofer. thanks for your help by the way all, you rule.

Nat
 
Are the promedia satelites 4 ohm? How well does that work with the 235?
 
natpond said:
nice, have my reciever now, its hooked up to my klipsch pro media satellites for the time being as i look for the best price on the 602s. any ideas how to hook the subwoofer up? as this thread has said, i like bass and it really isnt the same without a woofer. thanks for your help by the way all, you rule.

Nat
Click to expand...
If your receiver has a "pre output" for a subwoofer, then that's what you would use.
This means the amplifier will not amplify the subwoofer signal, and just send it to the subwoofer. You will then need a subwoofer that has its own power supply. I'm sure your receiver has some subwoofer options you can play around with.

As for the cable, you can get a decent subwoofer cable for cheap enough (10-30$us).
http://www.partsexpress.com/webpage...&&DID=7&CATID=55&ObjectGroup_ID=148&sm=0&so=0

~Enjoy
 
There is a sub-out on the back of the 235. It has preouts for all channels if you ever wanted to go and use a separate amp while using the 235 as a pre/pro.

You had a question regarding the 50+ watts being able to power a 602? Yes it will be able to power it to loud volumes.. this is not the problem.

The problem - to nitpick - lies in the amp's ability to produce high current. It doesnt matter if a cheap Kenwood amp can produce 150 watts per channel if it only produces 10 amperes of current continuously. Current will determine dynamics of your speakers, not the power rating (wattage).

My Rotel RB1070 produces about 50 amperes of continuous current while my previous HK 330 receiver only produces about 15-18 (we measured at the store). Did I hear a difference when I directly compared the two on BW702, Polk LSi9, and Martin Logan Mosaic speakers?

Hell yes. The difference was very apparent... and I'm talking about same volume level - so wattage isnt in question here, it's the current, dampening factors, and the overall build of the amps.

I probably went on a tangent... sorry.
 
Pinipig523 said:
There is a sub-out on the back of the 235. It has preouts for all channels if you ever wanted to go and use a separate amp while using the 235 as a pre/pro.

You had a question regarding the 50+ watts being able to power a 602? Yes it will be able to power it to loud volumes.. this is not the problem.

The problem - to nitpick - lies in the amp's ability to produce high current. It doesnt matter if a cheap Kenwood amp can produce 150 watts per channel if it only produces 10 amperes of current continuously. Current will determine dynamics of your speakers, not the power rating (wattage).

My Rotel RB1070 produces about 50 amperes of continuous current while my previous HK 330 receiver only produces about 15-18 (we measured at the store). Did I hear a difference when I directly compared the two on BW702, Polk LSi9, and Martin Logan Mosaic speakers?

Hell yes. The difference was very apparent... and I'm talking about same volume level - so wattage isnt in question here, it's the current, dampening factors, and the overall build of the amps.

I probably went on a tangent... sorry.
Click to expand...

You are spot on with your take on the current.

The one thing you failed to point out is that the Harman Kardon receivers are much better at delivering current than many of its competitors in their price class :)
 
i wondered how long it would take a "hk defender" to pop up and say "but... but... but... we're better than the rest"... ;)
 
ccotenj said:
it was a tangent, but one well worth going on... :)
Click to expand...

Ah.. always nice to get back-up and reassurance from someone (you) with more knowledge and experience on the subject matter. Lets me know that I'm typing right.

Hehehehe.... :D .
 
ccotenj said:
i wondered how long it would take a "hk defender" to pop up and say "but... but... but... we're better than the rest"... ;)
Click to expand...

Well there are other brands that are good too, like Denon and Onkyo... but HK gets my vote :)
 
firstly, the problem with hooking up the woofer, is its got this wierd plug, that almost resembles a PS/2 plug, but bigger, so i dont know how to plug it into my reciever.
secondly, about this current issue, will the 602s sound bad on my reciever? if so, can you reccommend another pair of speakers at about the same price point?
thirdly, what is a good subwoofer company. im looking for somethign compatable with my reciever, and also something with ALOT of oomph.

Nat
 
True. That 50W/channel on the HK receiver is the true continuous RMS power rating over all or most of the audible frequency range. Most other companies have switched to a Burst RMS rating measured at a single 1kHz frequency; thus the seemingly higher power ratings for the others. And if you look deep in the owners manual of those others, you will find that they deliver barely more wattage than the HK receiver when measured in continuous RMS wattage.
 
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