LSi15s versus LSi25s

aaharvel

EricT43 wrote:

Remember 200w is only going to be +6dB louder than 100w (correct me if I'm wrong guys).

+3db Eric.

shack

McLoki wrote:

That is +3db louder (3 db every time the power doubles).

The main reason that we recommend 200 wpc amps is not really for the watts. It is just that few amp companies start with 200wpc amps so you are moving up the amp food chain a little nomatter what you purchase. By not buying the cheapest amp in the line, many times, you get better current, slew rate, damping factor, etc.

Michael

It's also about "headroom".

cfrizz

Please explain what headroom is. Thank you!:)

shack wrote:

It's also about "headroom".

Frank Z

http://forum.ecoustics.com/bbs/messages/34579/109459.html

Dennis Gardner

headroom = reserve power.

Depending on how they rate amps (since no real standard exists), a 100wpc amp might have 3db headroom if it could produce a burst of energy = to 200 wpc for that dynamic passage that requires that amount of output. This isn't built into power supply and transistors ability to drive that much power, but more in huge capacitors that store the power an discharge when called upon to do so.

McLoki

Here is a quick rundown of amplifier terminology (also a great amp article that I came accross while researching)

Slew Rate: This is a term used to describe how quickly the output of an amplifier can track its input. Slew Rate is usually measured in V / usec. The higher the value (up to a point), the better the amp is at potentially reproducing the subtle nuances and dynamics associated with music reproduction.

Damping Factor: This is a quantity which defines how quickly the amplifier can stop a reproduced frequency such as a bass note. The higher the damping factor, the better the amp will control the woofer and help reduce overhang distortion (again to a point). The damping factor of an amplifier is mostly dependent on the output impedance of the power amplifier and the ability of the power supply which feeds the power amp.

Dynamic Headroom: The ability of a receiver or amplifier to output power at a significantly higher level than normal for short periods to accommodate musical peaks or extreme sound effects in films. This specification is important in home theater, where extreme changes in volume occur during the course of a film. Dynamic Headroom is measured in Decibels. If a receiver/amplifier has the ability to double is power output for a brief period to accommodate the conditions described above, it would have a Dynamic Headroom of 3db.

Watts and Current: This is a great article that it would be worth cutting and pasting, but you can read it yourself here....

Michael

2+2

Michael, that was a very informative post....thanks...funny that the article used the HP/Torque analogy...which is how I ended up thinking about the watts/current.

AndyGwis

I agree with the quality over quantity regarding watts.

My 75wpc Harman Kardon sounds just as powerful (if not moreso) than the Pioneer vsx-1015 I returned which boasts 120wpc, and my 65 wpc Carver amp seems even more capable than either of them.

Still need to hook them up bridged to my fronts for 200wpc.

Just to make sure, if the amp only can handle 8-ohms bridged and my monitors claim to be 8-ohms nominal impedence, I should be okay, right? I know nominal is an average so it might peak and valley higher and lower than 8-ohms.

Thanks!

Midnite Mick

I had that Pioneer before. It got some very good reviews and I thought that it sounded horrible. It produced the grainiest sound I have ever heard.

Mike

Dennis Gardner

You've got it right Andy, it is an average. Normally, speakers have lower impedance at the lower end of their frequency spectrum and higher at the high end. Some 4 ohm models from Polk dip under 2 ohms at their lowest point.