EAS subwoofer controller broblem

[romulo_rosil]

EAS subwoofer controller broblem

Hi! This is my EAS subwoofer controller project will not work; I gut this schematic from ESP.
My problem is:

Sound’s very poor and distorted.
How will this schematic work when all cascade op-amp are inverting, 180 degrees out of phase input of amplifier?
Is it possible that the inverting op-amp can operate the input of amplifier even out of phase?
Even in my experience assembling any circuits when inverting designs does not work, up to the point using theoretical ways to change components, with no effect.
Am I right saying that if the first op-amp is inverting and the next op-amp is non-inverting can work to phasing the input of amplifier?
Is there possibility that my project will work?
What pre-amp can I use to series from EAS before to power amp?
Am I right that EAS subwoofer controller is out of phase when input to the Power Amplifier?
Is this schematic diagram the original EAS?
Thus this circuit is really working?
Sorry for asking so many question, for I’m just a technician but really want to learn

[pinkmouse]

Hi Romulo, and welcome to diyAudio, but please next time put the content in the post rather than attaching it as a text file. I've sorted it this time, but don't do it again!

[infinia]

Hi Romulo,
welcome to DIY
All ESP designs are tried and proven designs according to their website.

Inverting opamp are OK trust me. If you have 2 cascaded inverting stages the output is now non-inverting correct?

Maybe you can double check your parts are installed correctly first. I know when my project is almost complete I hurry to get the result and sometimes make a little mistake.

Be patient and double-check everything slowly.
That is my advice for now.
good luck and come back soon

[clem_o]

Originally posted by romulo_rosil

How will this schematic work when all cascade op-amp are inverting, 180 degrees out of phase input of amplifier?

Is it possible that the inverting op-amp can operate the input of amplifier even out of phase?

Am I right saying that if the first op-amp is inverting and the next op-amp is non-inverting can work to phasing the input of amplifier?

Is there possibility that my project will work?

Am I right that EAS subwoofer controller is out of phase when input to the Power Amplifier?

Is this schematic diagram the original EAS?

Thus this circuit is really working?

Whoa! Whole lot of questions there!!

First, understand that the phase of a signal doesn't have anything to do with its acceptability to drive an amplifier! The signal can be inverted or not (and, note - you can only say that a signal is "inverted" or "out of phase" when it is referenced to some "other" signal!), and it will be fine to use that signal to drive an amplifier (you may also want to take note that an amplifier CAN be inverting or non-inverting). Ultimately, if you are one of those guys who believes in 'Absolute Phase', you can always invert the loudspeaker + and - connections to the amplifier to flip the signal around...

So: is it possible for the circuit to work if all op-amps are configured as inverting? Absolutely. There is nothing wrong with having them set as inverting. The first stage is a summing amplifier - it puts together the left and right channel signals, and to "work" as a true summing amp, the inverting configuration is needed.

The second and third stages are integrator stages to provide the dropping 6dB/octave required to drive the loudspeaker below its Fr. Integrator stages need to be inverting as well (i.e. its not possible to do a non-inverting integrator, or at least its not easy and simple).

The last stage is an optional phase inverter.

Now - count the number of inversions, and recall your math: a negative number multiplied by another negative number becomes positive right? So:

(-1) * (-1) * (-1) * (-1)

The result of an even number of inversions is equivalent to a non-inversion. The "reverse" and "normal" switch on Rod's schematic allows you to choose 'inverted' or non-inverted' phasing. Choose the setting that gives you less bass cancellation in the crossover region between your subwoofer and your main drivers.

Finally - "is there a possibility my project will work" - sure, just backtrack and ensure all your connections and components are 'right'. How are you powering up the op-amps by the way?

Cheers