"Power hungry" speakers

I am running b+w 801s which are said to be power hungry.I can tell you that I tried a 170 watt bryston amplifier and it drove the speakers to earth shattering levels.You must remember that 99% of the time your speakers are only using a few watts(usually less then 20 to be sure).I think this "POWER" thing has been very much over stated.99.9% of the time a 25 watt amp would do the job.However it is when the large dynamic swings take place that one could use more power...the differnce between a 300 watt amp and a 600 watt amp is only 3 db (for every 3 db increase then double the power is required)...so the difference between a 150 watt amp and a 300 watt amp is miniscule...

Start looking at bass transients into low sensitivity and / or low impedance and / or highly reactive loads and you need hundreds upon hundreds of watts. Combining all of the above will mean that you need a MONSTER sized amp to do the job right. This is part of the reason why high powered "digital" or high effiency amplifier designs have been finding their way into more and more systems. They can work quite effectively as sub amplifiers. There are some simple tricks that can be done to these amps that make them even better for this purpose. Sean
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I am well aware of what distortion represents.I can assure you that I heard very loud spl at low distortion lvls..I am not saying that a bigger amp isn't more desireable.But to get sound pressure lvls it is simple to figure out and NO...A few watts won't give it to you very very high spls as you have suggested..that is unless you speakers are extrememly efficient..ie.a speaker with 88bd efficiency goes as follows
1 watt= 87 db
2 watts=90 db
4 watts=93 db
8 watts=96 db
16 watts=99 db
32 watts=102 db
64 watts=105 db
128 watts=108 db
256 watts=111 db
512 watts=114 db
1024 watts=117 db
So ,I think the person who started this thread can see from the above what power is required to do what.Bottom line is this..Unless you have extremely inefficient speakers or you listen at very high levels then a 600 watt amp is not a must have.I am not saying it isn't better to have the power but if money is an issue etc then don't get too hung up on the wattage ...

El: My main system is actively crossed. No capacitors between amp and speakers other than the speaker cables themselves.

My Brother's system was previously quad-amped using passive networks a while back. He is now actively crossed and the passive networks came out of the system. The difference between active and passive was staggering to say the least. Bare in mind that the passive networks were VERY simple first order designs.

Sean125: The chart that you provided doesn't take into account the speaker going into compression and is also based on 1 meter spl's. Taking measurements at the seated listening position would alter those readings DRASTICALLY.

What others may find interesting and i find to be "coincidental" is that the mains in my HT system are rated at 87 dB's @ 1 w @ 1 meter. I was running these with two amps and passively biamping. I had 400+ wpc up top and 500+ wpc on the bottom end. When running these in two channel mode, even with this much power, i could drive the amps into saturation. Moving to a single amp that is rated at 1200 wpc and clips at slightly over 1450 wpc gave me the headroom that i needed. Not only does the system play louder, it does so in a cleaner fashion.

With that in mind, those interested in being able to sustain high spl's and / or obtain very dynamic peaks might want to print out and save the chart that you provided. They should also consider that they will be running two speakers when in stereo mode, so you effectively double the spl level for the same rated power output. As such, things are looking better in terms of trying to obtain clean dynamic output with lower power. Only problem is that most speakers WILL go into noticeable compression when you start throttling them.

The mains in my HT system are 4 ways with 5 drivers, limiting the power and bandwidth that any given driver has to deal with. If you want to "crank" the system and maintain linearity, you either have to use this type of approach ( multi-way with large surface area ) OR you can go with fewer crossover points, but use more total drivers i.e. two way line arrays, etc... Line arrays tend to maintain spl's better into the distance, so they are well suited to situations where you have a longer rooms and / or further listening positions.

Lots of variables in selecting speakers and there are quite a few different ways that "linearity" comes into play. Sean
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