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    4-channel amp produce distortion when bridged???

    Does a 4-channel amp produce have any noticeable distortion or overheating problems when bridged into two channels at 4ohms? I've been looking at the PPI P900.4 or the to drive my JBL C608GTI MKII components. Yes I know that's a little overpowered but from what I've read these JBL's can take some serious wattage. I just need to know if I should get this or find a good 2-channel, as far as SQ, distortion, and overheating go that is.







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    Re: 4-channel amp produce distortion when bridged???

    A good 4 channel amp shouldn't produce a lot of distortion when bridged. Generally you will get more distortion when you bridge 2 channels, but it shouldn't be noticable. If your not pushing it, the amp shouldn't overheat. It will probably produce more heat when its bridged then it normally would.




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    Re: 4-channel amp produce distortion when bridged???

    Have you considered going active?




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    Re: 4-channel amp produce distortion when bridged???

    Whats the difference between active and passive? I have read some about it but didn't quite understand.




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    Re: 4-channel amp produce distortion when bridged???

    active means you power each speaker (each tweeter and each woofer) from dedicated amp channels. so you need 4 amp channels for a 2-way component set. you don't use the passive crossovers with active (by definition it means using active (electronic) crossovers to filter signals to each speaker).

    passive means you use external passive (non-powered) crossovers (using resistors, capacitors, and inductors) to filter the signals. these rob power and produce heat and phase shifts.

    however, i've done much testing with several component sets active (non-bridged) vs. passive (bridged). and more power (bridged and passive) usually won out - especially at higher listening volumes. doubling voltage does wonders for headroom and dynamic range.

    distortion adds (since you have two channels, each with their own THD, driving the speaker), but any distortion common to the amp design can be cancelled at the speaker (if the noise out of phase).

    since bridging doubles voltage which quadruples power - you actually operate at a LOWER THD level when compared to the same output power with non-bridged. this is because bridging takes much less voltage to reach the same power level. (and less voltage = less amplification = less THD)



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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by keep_hope_alive View Post
    active means you power each speaker (each tweeter and each woofer) from dedicated amp channels. so you need 4 amp channels for a 2-way component set. you don't use the passive crossovers with active (by definition it means using active (electronic) crossovers to filter signals to each speaker).

    passive means you use external passive (non-powered) crossovers (using resistors, capacitors, and inductors) to filter the signals. these rob power and produce heat and phase shifts.

    however, i've done much testing with several component sets active (non-bridged) vs. passive (bridged). and more power (bridged and passive) usually won out - especially at higher listening volumes. doubling voltage does wonders for headroom and dynamic range.

    distortion adds (since you have two channels, each with their own THD, driving the speaker), but any distortion common to the amp design can be cancelled at the speaker (if the noise out of phase).

    since bridging doubles voltage which quadruples power - you actually operate at a LOWER THD level when compared to the same output power with non-bridged. this is because bridging takes much less voltage to reach the same power level. (and less voltage = less amplification = less THD)
    i think you may have lost the guy with that last sentence



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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by keep_hope_alive View Post
    active means you power each speaker (each tweeter and each woofer) from dedicated amp channels. so you need 4 amp channels for a 2-way component set. you don't use the passive crossovers with active (by definition it means using active (electronic) crossovers to filter signals to each speaker).

    passive means you use external passive (non-powered) crossovers (using resistors, capacitors, and inductors) to filter the signals. these rob power and produce heat and phase shifts.

    however, i've done much testing with several component sets active (non-bridged) vs. passive (bridged). and more power (bridged and passive) usually won out - especially at higher listening volumes. doubling voltage does wonders for headroom and dynamic range.

    distortion adds (since you have two channels, each with their own THD, driving the speaker), but any distortion common to the amp design can be cancelled at the speaker (if the noise out of phase).

    since bridging doubles voltage which quadruples power - you actually operate at a LOWER THD level when compared to the same output power with non-bridged. this is because bridging takes much less voltage to reach the same power level. (and less voltage = less amplification = less THD)
    Awesome responce.




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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by winkychevelle View Post
    i think you may have lost the guy with that last sentence
    eh, that last sentence just explains the math...

    i've worked out the equations by hand... math checks.



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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by keep_hope_alive View Post
    eh, that last sentence just explains the math...

    i've worked out the equations by hand... math checks.
    For high end components it is a good idea to go active, isn't it? As you said, at higher volume levels passive is generally better, is that universal?




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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by keep_hope_alive View Post
    eh, that last sentence just explains the math...

    i've worked out the equations by hand... math checks.
    ok second to last sentence, not the one in parentheses lol

    i got you but some guys will skim that and mis interpret your explanation



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    Re: 4-channel amp produce distortion when bridged???

    That a great response thanks and it's much simpler than what I tried to read. How bad really does a crossover use up power and create extra heat?




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    Re: 4-channel amp produce distortion when bridged???

    my comparison of active vs. passive is using the same amp for both. so take a 50Wx4 amp and run it active or bridge that amp to 200Wx2 and use the passive crossovers. the latter gives you much more power and dynamic range.

    but passive crossovers are annoying and cause many issues. eliminating them lets the amp drive the speaker directly - giving you full control over it.

    i run active and will always run active. you either live with less power (less volume output) or you buy larger amps.



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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by keep_hope_alive View Post
    my comparison of active vs. passive is using the same amp for both. so take a 50Wx4 amp and run it active or bridge that amp to 200Wx2 and use the passive crossovers. the latter gives you much more power and dynamic range.

    but passive crossovers are annoying and cause many issues. eliminating them lets the amp drive the speaker directly - giving you full control over it.

    i run active and will always run active. you either live with less power (less volume output) or you buy larger amps.

    I MUST HAVE CONTROL!!! lol THANKS!




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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by PrinceCharming View Post
    That a great response thanks and it's much simpler than what I tried to read. How bad really does a crossover use up power and create extra heat?
    the heat is just wasted power and lower amp efficiency since the amp produces signals that the crossovers attempts to block with impedance. amplifiers don't like seeing large swings in impedance - and those swings will affect what you hear.

    the impedance plot of a comp set is not flat...




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    Re: 4-channel amp produce distortion when bridged???

    Quote Originally Posted by keep_hope_alive View Post
    my comparison of active vs. passive is using the same amp for both. so take a 50Wx4 amp and run it active or bridge that amp to 200Wx2 and use the passive crossovers. the latter gives you much more power and dynamic range.

    but passive crossovers are annoying and cause many issues. eliminating them lets the amp drive the speaker directly - giving you full control over it.

    i run active and will always run active. you either live with less power (less volume output) or you buy larger amps.
    i didnt think id ever read you typing that, though to a point i agree, but again a good install can overcome alot of the output problems. which the methods ive used in the past have been learned by studying your installs, so like i said shocker to hear that from you. cant wait to try that fiberglass trick in my new car!! just waiting for the sundown comps to arrive then maybe the mille when the next job starts up



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