# DSP and Passive Crossovers



## troutspinner (Nov 8, 2013)

Has anyone ran a DSP to components keeping the components passive crossover in place?

I am in channel hell right now as I "think" I want to keep my rear fill. I either have to buy an additional 2 channel amp or run the components with passive crossovers. I could power the rears off of the HU but those speakers would be missing DSP tuning and TA.

Thoughts?


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## Alrojoca (Oct 5, 2012)

I assume The DSP has 8 channels, if that's the case assuming you use a 2 way front and subs they will be amplified and have full benefit from the DSP, you will need an amp for the rears, to use the DSP with those. Or drive the rears with the HU, if the HU has TA great, if not assuming it has a HP and level output, you can adjust it, assuming the DSp can sum the channels to have 6 out of 4 ch, to use the HU to drive the rears if no extra amp is available 

If you only have 6 channels available for the DSP, you will need to choose between no rears and full active 2 way and sub, or drive the components with the passives, using only the HP at 70- 80hz from the DSP and TA, EQ, level and do all you want with the DSP, TA for the fronts may not give you the best results, it's a choice you will need to make, and you will have rear fill amplified this way and using the DSP since you will be amplifying 6 ch, 2 for the front 2 way passive, 2 for the rear and 2 for the sub or subs


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## troutspinner (Nov 8, 2013)

I do have 8 channels on the DSP, the proper way is adding an amp....I know this.  but I am just wondering if others have tried a similar setup and been happy with the results.


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## Alrojoca (Oct 5, 2012)

If you want rear fill, it's a choice with the 2 options, either get an extra amp, or use passives with the fronts.

It really depends on what you consider more important

1.Better cleaner sound in the front and no rears or get extra amp to get the best of both

2. Have Rears with no amp and sacrifice SQ in the front stage, by not bi amping the fronts


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## troutspinner (Nov 8, 2013)

Good point, I do not want to sacrifice quality which I guess is kind of why I am asking the question. Leaving the rears out or on HU power is not going to be quality so I was thinking the opposite scenario with a passive XO up front....which ultimately would be less quality.

Since I am new to DSP I think I will leave the rears out of the equation until I get past my learning curve. At that point if I want to have rears I'll buy another amp.

Thanks


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## ccapil (Jun 1, 2013)

can you list all the gear you have. Im sure you can bi amp the rear Or run them off the head unit if needed. I would leave the fronts active in any situation. list the gear you have, you have 8 channels on the dsp so how many amplifier channels are available ?


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## troutspinner (Nov 8, 2013)

Thank you for your help. Here is my setup;

2014 Ram 8.4a/RA3 HU (No summing worries, all 4 channels are full signal)
Precision Power DEQ.8 (8 Channels)
Alpine PDR-V75 (5 Channels)
Focal 165AS Mid/Tweeters (Fronts)
Focal 165AC 2-way (Rear)
JL 10W0V3-4 Sub (Single In Ported Fox Enclosure)


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## teldzc1 (Oct 9, 2009)

Can you power the rears with factory power an leave them out of the dsp chain?


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## Alrojoca (Oct 5, 2012)

troutspinner said:


> Has anyone ran a DSP to components keeping the components passive crossover in place?
> 
> I am in channel hell right now as I "think" I want to keep my rear fill. I either have to buy an additional 2 channel amp or run the components with passive crossovers. I could power the rears off of the HU but those speakers would be missing DSP tuning and TA.
> 
> Thoughts?


The OP wants rear fill with TA and processing. It would make sense not to care about processing with rear fill and use the HU to drive them if possible.

From 2 HU ch to 6 channels for the DSP for a 2 way active and sub, is possible and He can drive rears with the HU and no processing or TA, since it is a stock HU.






troutspinner said:


> Good point, I do not want to sacrifice quality which I guess is kind of why I am asking the question. Leaving the rears out or on HU power is not going to be quality so I was thinking the opposite scenario with a passive XO up front....which ultimately would be less quality.
> 
> Since I am new to DSP I think I will leave the rears out of the equation until I get past my learning curve. At that point if I want to have rears I'll buy another amp.
> 
> Thanks


I would do this and concentrate on learning how to tune a front 2 way active and sub system. 

Only connect the rears if 

1 you have passengers in the rear seats all the time or it is a large cabin or van
2 want to use only 2 ch for the DSP to have 6 active channels
3 want to wait until you get your front stage like you want it, then get an extra two ch amp to have full DSP processing for 8 channels including rear speakers. 

My opinion is that you focus on the front stage, once you are happy, you may not even want rear speakers or spend extra on a 2 ch amp or even connect them. You can always connect them without any processing and fade them out or in when needed, but never faded in when tuning the front stage


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## troutspinner (Nov 8, 2013)

Alrojoca, yep. I agree with your opinion and that is what I will do. I can always add later but creating a convoluted way is just going to slow my progress. 

Thanks


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## JVD240 (Sep 7, 2009)

Personally, if this is your first experience with a DSP, I would stick to the 2-way front stage + sub and learn on that. There's a lot of great sound you can extract from just that.

When you are comfortable or get bored add the rear fill.


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## miniSQ (Aug 4, 2009)

I think your over all SQ will be better without using rear fill. But if you already have them, and you are only lacking an amp, you should be able to pick up a 50x2 amp for the rears for under $75 used.


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## bigaudiofanatic (Mar 1, 2009)

My nightmare is as much as I want to go 3 way active with my morels and 3sixty.3, there is absolutely no room in the door grommet in my G37 for new wire. To add insult to injury I'm also stuck with the factory integrated radio. So I have to A run the DSP from the factory signal. B use the 3 way passive crossover. So what am I loosing other then power robing passive crossovers? And am I not seeing another option?


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## rob3980 (Jun 11, 2010)

My escalade currently has a active 3 way in front and passive 2 way in the rear all running through a Helix mk2 Pro dsp.


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## bigaudiofanatic (Mar 1, 2009)

rob3980 said:


> My escalade currently has a active 3 way in front and passive 2 way in the rear all running through a Helix mk2 Pro dsp.


How did you set your crossover for the passive ones? Sense running both stacks crossover curves or did you set your dsp to run full for them?


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## Lee.moore (Jan 8, 2020)

Is there any updates on this I’m about to set me system up this way. 
channel 1/2 front left and right
Channel 3/4 rear left and right 
Channel 5/6 subs 
System 
C2 165 components front and rear
RD900/5
Helix mini


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