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regards

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Agree but then, what you usually feed the speakers, ie, what power amp do you use with JBL speakers ? example: a 4670D has an IEC of 600w and a continuous program capacity of 1200 w so you connect a 2x600watts (for 2 4670D) or a 2x1200 or the former bridged ?
what sound category is cinema sound ? studio, live concert etc ? seems JBL stresses deeply these categories in its FAQ. I'd say cinema sound is much closer to studio sound than live concerts where clipping is so common, as almost constant. As for subwoofers, JBL recommends adding subs rather than increasing the watts ( they recommend usually 800-1000 watts per 4645C/4645B). there's clear gain in adding subs. Talked to a net friend who is deep into live sounding, concerts etc and he almost always screams 1500-2000watts for this kind of subs.... I also agree that such powers would be EXCESSIVE in a home theater configuration... totally.

thanks a lot for your comments. appreciate.
PS: I realize I forgot you almost already answered me on this issue on a previous post...
maybe I should stop torturing myself and get those DCA amps ( 1222 for 3677 and 3422 for the subs , should be PLENTY enough with AWG 8..... ).

thanks again. but this gets more confusing! ( note: the 600w was related to the 4670D, which I don't have. I only have models 3677 and 4645C, and probably 8340 for surrounds later on).
what you then say is minimum IEC rating ( continuous pink noise or AES, as JBL states) thus if a speaker has an IEC of 250w, power it with an amp of minimum 250w per channel, right ?
But then you say cinema sound is considered as studio sound, thus , you should feed the speaker... hold on.... 4 times its IEC rating (and adjust level with volume on the processor)! That's what JBL says in its FAQ.
So, based on the few posts here and on other threads, there seem to be 2 schools among film handlers: some say go with the log curve and feed the necessary watts to reach 105dB as per the 2/3 distance of the room ( and all the SPL meters and tools used to measure SPL in-rooms levels), and another school might go with JBL's recommendations, which says 2 or 4 times the IEC ratings, no matter what the room size, and adjust the level via the volume on the processor. I hope this is clear
The second "school" would rule out the cost factor since this means beefier amps, many bridged btw. What strikes me still is the fact that most of these JBLs are very sensitive, some as high 107db/1W/1m and thus start producing high SPL level even with small amount of watts... so why going so sky high with their recommendations (2x the IEC is ok, but 4times!!)? is this solely due to headroom requirements and lowest possible THD ? peak transients capacity ?

here's what they say: (www.jblpro.com FAQ):
"How do I choose the right amplifier power for my speaker system?

Ideally you should pick an amplifier that can deliver power equal to twice the speaker's continuous IEC power rating. This means that a speaker with a "nominal impedance" of 8 ohms and a continuous IEC power rating of 350 watts will require an amplifier that can produce 700 watts into an 8 ohm load. For a stereo pair of speakers, the amplifier should be rated at 700 watts per channel into 8 ohms.
A quality professional loudspeaker can handle transient peaks in excess of its rated power if the amplifier can deliver those peaks without distortion. Using an amp with some extra "headroom" will help assure that only clean, undistorted power gets to your speakers. Some professional amplifiers are designed so they have additional headroom. These amps can cleanly reproduce transient peaks that exceed the amplifier's rated power. In this case select a model with an output power rating equal to the continuous IEC power rating of the speaker. Consult the amplifier manufacturer or owner's manual to learn more.
In some applications, such as critical listening in a studio environment, it is important to maintain peak transient capability. For these applications, use an amplifier that can deliver 6db (or four times as much) more power than the continuous IEC power rating.
If budget restraints or legacy equipment force you to use an amplifier with less power, extreme care should be taken to see that the amplifier is not driven into clipping. It may surprise you to learn that low power can result in damage to your speaker or system. Download our Danger: Low Power (Adobe Acrobat, 204kB) tech note for more information. "

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