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2Addicts | BMW 2-Series forum Technical Topics Navigation, iDrive, Audio, Video, Bluetooth, Phone, Cameras, Electronics 8 Channel DSP, Run Fronts Active or Passive?

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      08-22-2019, 05:35 PM   #1
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8 Channel DSP, Run Fronts Active or Passive?

As most DSPís seem to be 8 channel, thinking Match Up7, PDP-E800DSP or MS8, just wondering if it is better to run front Mid and Tweeter Active or Passive?

I guess Passive allows use of Centre Speaker and Active would not if using 6 channels for each of the front speakers and 2 rear.
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      09-01-2019, 05:18 PM   #2
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So here's the deal:

when you have your tweets and mids (the ones in the door not the mids under the seat) they will have distinct capabilities about how well they play the upper and lower frequencies. The tweets can only play so low, the mids can only play so high, and when they overlap it changes how that sound is perceived.

The crossovers provided by the manufacturer of a component set (either separates or coaxials) are their 'best guess' in terms of how the tweeter starts to lose power and the mid takes over as frequencies go down (and vice versa as frequencies go up.)
There is a point where the frequencies are played by both speakers and 'cross' over each other (hence the name) and the crossover filters out low frequencies from the tweet and higher frequencies from the mid allowing for a smooth transition as the upper frequencies transition to the lower and the tweeter 'hands off' playing to the mid.

The speakers capabilities are universal, and those crossovers as provided by the manufacturer are not adjustable. When you put them in a car, the interior of the car changes how those frequencies 'gain' power based off reflections etc. inside as well as your proximity to the speakers and the position of your head. The crossover can either help or hurt as audio is subjective. No way to know until you try.
(this is why some person will say speaker X has muddy midbass and the other says they are awesome. The answer is they are both: it depends on the way they are installed, where they are installed, and the listeners ears).

If you run active, you eliminate the guessing altogether and specifically adjust how the speakers will play in your vehicle to your liking. The crossover is 'infinite' and you can tweak how the frequencies roll off. This can improve the sound by enhancing the parts you like and mitigating the parts you don't.
Understand this last part is black magic. Some people don't have the time or patience to do this, or don't want to pay an audio shop to do it for them. It of course must be done after the speakers are broken in which means quite a bit after the initial install, so there's a delayed satisfaction and many people aren't patient, they just want to put passive crossovers and be done.

So sounds like active is the way to go right? You've already spent the money on speakers why not have them play as best as they can?
Here's the catch: so for example you have 4 channels in your amp, each channel goes to each corner of the car for the group of speakers mounted there.
That works with passive as the crossover passively sits on that single amp channel filtering and sending the filtered audio to each tweet/mid.
With active, you need a dedicated amp channel per each tweet or mid or sub.

That means if you have 4 channels in your amp, you can only run the tweet and mid in your front sound stage. No rears, no sub. They need their own amps.

Of course you have 8 channels. Which is awesome. You can then run to a tweet and mid in both front and back and leave a pair for the subs - or bridge the last two 'spare' channels for mono and leave for the "subs" under the seat so they get more power.

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