Going Active Questions

[cruizer]

Trying to go active with my truck. Getting confused and what not; plan is tweets, front mids, rear mids and subs. Gonna start with the head unit here: most head units have 6 outs, FRONT, REAR and SUBS. Most EQ's seem to have 4 in and 4 out. Most 4-way crossovers seem to have 4 in, 8 out.

Question 1)

Do I look for a head unit with only 4 out, OR do I get one with 6 and ignore the subs, OR use only a 3-way crossover because most aftermarket head unit SUB outs are good enough and don't require a crossover?

Thanks!

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[fasfocus00 5,000+ posts]

get an Audiocontrol 6XS with the freq modules you want and done.

 

[UMWDawg92 10+ year member]

By "rear mids" do you mean rear fill?

 

[Kangaroux 5,000+ posts]

By "rear mids" do you mean rear fill?

derp

 

[UMWDawg92 10+ year member]

derp

I was trying to make sure he didn't mean that he was doing a 3 way front... kinda asked it weird though

 

[keep_hope_alive Premium Member]

your plan sounds good. rear mids for rear fill can work great with time alignment.

i am active with a HU + active crossover currently (H701 pulled out). I have an Alpine CDA-9887. Awesome HU for an active system, and $250 is a used price lately. Pioneer DEH-880PRS or 800PRS are two other great head units for active setups. i have an active 3-way front + sub currently. my HU has 3-way output capability. so the HU bandpasses the midbass and high passes the mid/tweet with an active x-over (or amp x-over) that divide the tweet and mid. my xtant amps let me use 5kHz crossover points.

you can run the tweets and mids off the front outputs, rear mids off the rear outputs, and subs off the sub outputs. to go active between mids and tweets you can use either amp crossovers (if they go to 5kHz) or insert a 2-way active crossover.

you don't want a 6-channel crossover/eq since you lose time alignment front/rear. time alignment is key to a good sound stage, and you need to be able to delay rear speakers if you want a sound stage. bandpass rear mids between 400Hz-4kHz (or thereabouts). try to keep the tweeter crossover point at or above 5kHz so imaging is intensity based (IID) and not time based (ITD). this allows you to simply delay based on mid locations and ignore tweeter time arrival. off-axis tweeters help further by naturally providing attenuation to the nearest passenger.

 

[cruizer]

Thanks for all the replies!

First, I should mention I am on a moderate budget. The head unit I am currently looking at is a DEH-P7200HD.

I do mean rear fill, please excuse my ignorance, not all there sometimes.

 

[vaiboy 10+ year member]

His deck doesn't have time alignment but the AudioControl 6XS will do almost exactly what he needs. It has front highpass, front bandpass, rear highpass, and subwoofer outputs.

 

[UMWDawg92 10+ year member]

your plan sounds good. rear mids for rear fill can work great with time alignment.
i am active with a HU + active crossover currently (H701 pulled out). I have an Alpine CDA-9887. Awesome HU for an active system, and $250 is a used price lately. Pioneer DEH-880PRS or 800PRS are two other great head units for active setups. i have an active 3-way front + sub currently. my HU has 3-way output capability. so the HU bandpasses the midbass and high passes the mid/tweet with an active x-over (or amp x-over) that divide the tweet and mid. my xtant amps let me use 5kHz crossover points.

you can run the tweets and mids off the front outputs, rear mids off the rear outputs, and subs off the sub outputs. to go active between mids and tweets you can use either amp crossovers (if they go to 5kHz) or insert a 2-way active crossover.

you don't want a 6-channel crossover/eq since you lose time alignment front/rear. time alignment is key to a good sound stage, and you need to be able to delay rear speakers if you want a sound stage. bandpass rear mids between 400Hz-4kHz (or thereabouts). try to keep the tweeter crossover point at or above 5kHz so imaging is intensity based (IID) and not time based (ITD). this allows you to simply delay based on mid locations and ignore tweeter time arrival. off-axis tweeters help further by naturally providing attenuation to the nearest passenger.

This^^ would work perfect for you

 

[cruizer]

So basically spending the money on an active head unit, and a 2-way active crossover, and the head unit takes care of the rest. No need for another crossover or EQ?

 

[keep_hope_alive Premium Member]

correct. active-capable HU that has a 3-way output option. i think you want T/A if you're going through the effort. get a nice used deck with T/A. even a CDA-9855 or CDA-9835/33 has 6-channel T/A - and some limited crossover functions. plan your system with diagrams and read owner's manuals so you plan your connections and crossover points ahead of time. you know you need the following:

Front Tweeter: high pass filter around 5kHz

Front Woofer: band pass filter from 80Hz - 5kHz

Rear Mid: band pass filter from 400Hz - 4kHz

Subwoofer: low pass filter from 80Hz.

those are your desired starting points. additionally, you'd like to have level option for each independent of gain setting (if possible). you want to easily adjust level while listening to get adequate balance, while your gains are set to provide rated power without clipping at your desired HU max volume. the midrange speaker could use passive filters to achieve desired ambiance - 6dB/oct would be simple to implement.

the real reason to go active is to gain independent control over the speakers. most people do this for T/A. you can do this to have tweaking ability of frequency response via crossovers and level at amp channels. then use all of this to create a sound stage and increase your volume level.

a 6XS will give you active crossovers, but eliminates control at the HU and eliminates T/A ability - and all tuning is done from the trunk (since that's the only place to put the 6XS). i've had trunk mounted processors/eq's/crossovers, and it's annoying as hell. i much prefer tuning by ear from the driver's seat. like when you have a 3 hour drive, you get to tune the whole time. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[cruizer]

Thanks for the info! It's a lot to go over, I will definately be back with more questions. I am bidding on a DEH-880PRS I managed to find on ebay. If I get it, I'll see where I go from there!

 

[fasfocus00 5,000+ posts]

correct. active-capable HU that has a 3-way output option. i think you want T/A if you're going through the effort. get a nice used deck with T/A. even a CDA-9855 or CDA-9835/33 has 6-channel T/A - and some limited crossover functions. plan your system with diagrams and read owner's manuals so you plan your connections and crossover points ahead of time. you know you need the following:
Front Tweeter: high pass filter around 5kHz

Front Woofer: band pass filter from 80Hz - 5kHz

Rear Mid: band pass filter from 400Hz - 4kHz

Subwoofer: low pass filter from 80Hz.

those are your desired starting points. additionally, you'd like to have level option for each independent of gain setting (if possible). you want to easily adjust level while listening to get adequate balance, while your gains are set to provide rated power without clipping at your desired HU max volume. the midrange speaker could use passive filters to achieve desired ambiance - 6dB/oct would be simple to implement.

the real reason to go active is to gain independent control over the speakers. most people do this for T/A. you can do this to have tweaking ability of frequency response via crossovers and level at amp channels. then use all of this to create a sound stage and increase your volume level.

a 6XS will give you active crossovers, but eliminates control at the HU and eliminates T/A ability - and all tuning is done from the trunk (since that's the only place to put the 6XS). i've had trunk mounted processors/eq's/crossovers, and it's annoying as hell. i much prefer tuning by ear from the driver's seat. like when you have a 3 hour drive, you get to tune the whole time. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

you clearly have never owned or used a 6XS or don't understand where t/a occurs in the signal process. you usually have great information and is on point but this one is clearly just not true. if the headunit has time alignment ability, it delays the signal to a particular channel giving the sound image. it has nothing to do with the 6XS. the 6XS still processes the signal that the headunit sends no matter what. the 6XS just dictates the frequencies as it is just an active crossover. the 6XS just separates the front channel to 4 channels of output. I have a headunit with t/a and have a 6XS installed and I can change my listening position with no issues as these are 2 completely separate things that have no affect on the other.

 

[vaiboy 10+ year member]

you clearly have never owned or used a 6XS or don't understand where t/a occurs in the signal process. you usually have great information and is on point but this one is clearly just not true. if the headunit has time alignment ability, it delays the signal to a particular channel giving the sound image. it has nothing to do with the 6XS. the 6XS still processes the signal that the headunit sends no matter what. the 6XS just dictates the frequencies as it is just an active crossover. the 6XS just separates the front channel to 4 channels of output. I have a headunit with t/a and have a 6XS installed and I can change my listening position with no issues as these are 2 completely separate things that have no affect on the other.

Actually, in a way you are both right it just depends on the situation. In the OP's case a deck with T/A and the 6XS would work because the T/A would still function to align the front and rear mid. The tweeters alignment will be linked to the front mid but it shouldn't matter if it's crossed at ~5k. If you tried to run a 3-way front stage with rear fill using the 6XS you could run into problems. You would have to split the front mid or high output with another crossover, then all 3 front speakers alignment would be linked. So if the alignment between the midbass and mid was off there would be no way to correct it.

In the OP's case he could probably ignore the T/A and use the fader to lose the rear fill when he wasn't carrying passengers if it bothers him.

Personally I would rather focus on path length and aiming, the cheapest T/A available. Plus in my experience the head unit is normally the least reliable part of the install. If your headunit breaks or is stolen you will have to find another with the same features to replace it, it's not always that easy especially if the deck was over 5 years old. Having a separate EQ and crossover means you can swap the deck without too much hassle, all it needs is front and rear outputs.

 

[keep_hope_alive Premium Member]

My bad, I started that post, walked away, then came back to finish and lost my train of thought and forgot about its inputs. The 6XS has six inputs and eight outputs to facilitate running active with a front 2-way and rear speakers and sub Both front outputs share input signal. Rear is high pass only.

Reasons why the 6XS isn't ideal:

The crossover modules are a PITA.

Rears are difficult to bandpass.

Good HU + 2-way can be more flexible.

Thanks for correcting me.