Film-Tech Forum ARCHIVE: 120 W vs. 250 W amp vs. speaker sound?

This is topic 120 W vs. 250 W amp vs. speaker sound? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Paul Vollmers (Member # 927) on 05-15-2013, 05:52 AM:

Would there be any sound quality difference between using a 120 Watt amp vs. a 250 Watt amp behind the screen? using a CP65 processor.

Posted by Gavin Lewarne (Member # 5397) on 05-15-2013, 08:33 AM:

That all depends really on how much power your speakers require to generate the required sound pressures. Generating pink noise to 85db requires less overall power than big bass and lower frequency noises.

If you are nearing clipping generating pink noise to 85db on the channels in question on a 120w amp then you absolutely should go for the bigger option

If the 120w is sufficient and the EQ is re-done they should sound more-or-less the same, but be aware of lower frequencies using more power....if your amp reaches clip it can damage the speaker in a short amount of time

Posted by Jarod Reddig (Member # 6363) on 05-15-2013, 11:20 PM:

What are your screen channel speakers?

Posted by Cameron Glendinning (Member # 3516) on 05-16-2013, 05:28 AM:

It really just depends on the efficiency of the speakers and the size of the room. For instance a classic Altec speaker can fill a large room with only a few watts. In the early 1960's a 60w amp was considered huge. The more headroom or bigger amplifier however tends to be better.

High efficiency speakers can produce over 100db @ 1w @ 1m. Home speakers might only be say 87db @ 1w @ 1m. So an Altec A4 might be louder at 1w than a home speaker at 100w.

Also the further away you are from the speaker the more watts required to maintain the same sound level.

It's also the case that a 250 w amp can't produce twice the output than a 120w model. To get twice as loud as a 120w you might need a 1200w amp if the speaker can take it.

Posted by Mike Blakesley (Member # 26) on 05-16-2013, 09:48 AM:

For what it's worth, one thing I learned from my audio sales days is that it's easier to ruin a speaker by overdriving it with too little power, than it is with too many watts. Use the larger amp if you can.