# PPI dcx-730 and Rockford Fosgate 3sixty.2 comparison



## npdang (Jul 29, 2005)

A big thank you to OldOneEye from Sounddomain for providing the RF 3sixty.2. 

I had some time to play with both the PPI dcx-730 and the RF 3sixty.2 processors. After evaluating both units over the weekend, I must say that we should consider ourselves very fortunate to have such affordable, convenient, and high quality processors available today. Anyone who has owned any of the older generation Altomobile, Clarion, Alpine, or Pioneer processors will know what I mean. Especially those who have used the old large and bulky analog processors, or who have converted pro-sound gear for car use.

My quick take on both units; For stereo processing with a clean pre-amp output the PPI is a more flexible processor with an easy to use remote control and noticeably more powerful outputs. I especially like the fully adjustable and independent parametric eq. Parametric eq’s in my opinion offer more flexibility in response shaping than traditional graphic eq’s, albeit they can be a bit more challenging to use. Having an independent bank of bands for each input and output allows you to tweak each driver individually, without affecting the others. This is a huge point, for example allowing you to boost the treble on the driver side tweeter which in most installs sits far off-axis as compared to the tweeter on the passenger side. 

I also especially enjoyed the ability to change crossover types, from butterworth to linkwitz riley. This is an added benefit that you rarely see in a car audio unit. This is important because both filters have significantly different summing and responses at the crossover point. The PPI unit also allows you to reroute the signals from the inputs however you’d like to the outputs. Nice touch, although something I don’t really use. The wired remote control unit was easy to use, but not as nice as could be. For a car audio processor it worked wonderfully, but compared to the pro-sound units I’ve used it was sluggish to make changes.

That’s not to say that the RF unit is a slouch either. The biggest advantage it possesses is that it allows for easy OEM integration. Connecting the speaker outs from my stock headunit directly into the RF unit was simple, and the unit automatically took care of all the summing and frequency response correction. Setup was very easy and hassle free. The resulting output was roughly +/- 2db from 30hz to 18khz. I noticed a rather steep dropoff at both ends and the output phase response is perhaps not as smooth. This was a significant improvement over the stock processing, which had significant levels of bass and treble boost. However, with stock speakers the sound was noticeably worse. Not surprising as the OEM processing was originally meant to compensate for deficiencies in the speakers location and response. While not as good as a quality aftermarket headunit, it’s still good enough and significantly better than a traditional line out converter. 

Control of the unit came from my handy Palm OS phone. It’s cumbersome and not as quick as the PPI unit, and I often got disconnected while in the middle of setting something up. Frustrating, but fortunately rumor has it that a software interface is in the works.

To sum up:

PPI advantages:

Customizable signal routing
Parametric EQ
More filter/crossover selections
Easy to use included remote control
Strong pre-outs 

PPI disadvantages:

Good luck finding one
Limited warranty/support
No oem interface/correction
Parametric EQ can be confusing to use for a beginner

RF advantages:

Oem interface/correction
Wireless control interface
Graphic EQ can be easier to use for beginners
RF support and warranty
Very usable, but lower strength outputs than the PPI

RF disadvantages:

Less crossover options with respect to slopes and filter types 
Less options with response shaping 
No signal routing customization
Remote control interface not included

Both units are extremely small, and easy to hide away. You can also start the car with the stereo playing without suffering any ill effect. Honestly, I wouldn’t hesitate to use either one in my car. In my experience, both units are of much higher quality than anything I’ve used before without any of the small idiosyncrasies that you usually have to put up with. It’s also nice that both units have an extra center channel output and a fully functional sub output, as well as 3 pairs of inputs instead of just one. For the future, it would be nice to see a digital input and room correction, but for now I’m more than satisfied.


----------



## chuyler1 (Apr 10, 2006)

I have only had my DCX for a few days but I wasn't aware that it had center channel processing like the 360. I know you could perform a L+R sum output but I don't think it does any processing. Or maybe the 360 doesn't either???

Based on the research I did, the 360 outputs are fixed at front L+R, rear L+R, Sub, and Center. Correct me if I'm wrong about that.

Also, whereas the DCX has identical processing capabilities for all 6 channels, the 360 limits the subwoofer channel and I think the center also.

I'm not trying to pick holes in your review...but I did similar research before buying my DCX so I am just sharing some differences I thought I found when comparing the two.


----------



## cvjoint (Mar 10, 2006)

How did you evaluate the voltage outs of the PPI? In my experience both the h701 and the Eclipse cd7000 units had stronger outs when you have to adjust the volume on the PPI to get rid of some of the background noise (12-15 steps or so IIRC). The usable range of the pre-outs is therefore subpar to most 4v and 5v units, even an analog PPI xover I used before.


----------



## npdang (Jul 29, 2005)

No please do. I only used these for a few days, so obviously I haven't explored every little nook and cranny. I'm also typing this from memory 

What it comes down to I think, is just how much BETTER these 2 units are than any of the old stuff I've used. There's just no quirky behavior, noise, or anything whatsoever. You hook it up, and it works plain as that. The fact that each channel has it's own independent processing is huge compared to the old analog units as well.

The RF sub and center channels I wouldn't really call limited. Although not similar in processing as the other channels, it's still overkill for a sub or center.


----------



## chuyler1 (Apr 10, 2006)

I noticed on my bench that I could get rid of some static by dropping the output volume from 0 to -12db or more. I didn't measure the output voltage afterward though.


----------



## npdang (Jul 29, 2005)

cvjoint said:


> How did you evaluate the voltage outs of the PPI? In my experience both the h701 and the Eclipse cd7000 units had stronger outs when you have to adjust the volume on the PPI to get rid of some of the background noise (12-15 steps or so IIRC). The usable range of the pre-outs is therefore subpar to most 4v and 5v units, even an analog PPI xover I used before.


I didn't have any noise with the output level all the way up. I used the pre-amp outs on my stock headunit. The h701 is much weaker in my experience.


----------



## chuyler1 (Apr 10, 2006)

npdang said:


> The RF sub and center channels I wouldn't really call limited. Although not similar in processing as the other channels, it's still overkill for a sub or center.


My point was, if you wanted to run 4-way you couldn't do so with the 360 due to the limitations. With the DCX, you could run 4-way and split the sub channel for midbass and subwoofer using an amplifier's basic crossover. You would lose time alignment on these two output stages but it could be done while keeping full control of your tweets and mids. Your options are limitless.


----------



## andthelam (Aug 9, 2006)

npdang said:


> I didn't have any noise with the output level all the way up. I used the pre-amp outs on my stock headunit. The h701 is much weaker in my experience.


I too have no noise and my volume is set at 0db subs and -3db tweets and mids.


----------



## npdang (Jul 29, 2005)

chuyler1 said:


> My point was, if you wanted to run 4-way you couldn't do so with the 360 due to the limitations. With the DCX, you could run 4-way and split the sub channel for midbass and subwoofer using an amplifier's basic crossover. You would lose time alignment on these two output stages but it could be done while keeping full control of your tweets and mids. Your options are limitless.


Understood. But is it fair to call it limited if that's not the intended application? I'll have to check again when I get home but I don't see why you couldn't do the same thing with either unit?


----------



## dual700 (Mar 6, 2005)

Bah!
H701 FTW!! 
Can u flip phase with either RF/PPI? Not with ppi IIRC


----------



## ATB (Aug 30, 2005)

The 3sixty.2 is one of the few options for those of us that _can't_ replace our head unit when said head unit has nasty built in processing. For my 05 Legacy, the head unit and auto climate control share a vertical circuit board just behind the integrated face that have the displays and controls for both units mounted to it. Just way too much custom work to even attempt to get an aftermarket unit in there.

My 3sixty.2 should hopefully be going in sometime in the next month.


----------



## t3sn4f2 (Jan 3, 2007)

NPDANG, can you expand on what you ment by they are not as good as a quality after market headunit, did you say that because of the inherent quality limitations of most OEM headunits that feed these devices or is it something more that would not be helped by sending them a clean signal from a quality source straight into the AUX in. I ask because I am interested in keeping the OEM headunit and using the AUX in on either the JBL MS-8 or the Alpine PXE-H650 and thought that the preamp stage in them would be up to par with a good headunit. Thanks


----------



## azngotskills (Feb 24, 2006)

That JBL MS-8 looks really promising and would compensate for the signal out of the OEM headunit...if you didnt know there is a thread on audiogroupforum.com that really explains what the unit does and how its implemented. I honestly has the capability to do more that than either the PPI or 3sixty.2


----------



## t3sn4f2 (Jan 3, 2007)

azngotskills said:


> That JBL MS-8 looks really promising and would compensate for the signal out of the OEM headunit...if you didnt know there is a thread on audiogroupforum.com that really explains what the unit does and how its implemented. I honestly has the capability to do more that than either the PPI or 3sixty.2


Thanks, Yeah I've been keeping up with that thread, asking other things about it too, I assume that the preamp on that unit must be pretty good but wanted to make sure.


----------



## andthelam (Aug 9, 2006)

dual700 said:


> Bah!
> H701 FTW!!
> Can u flip phase with either RF/PPI? Not with ppi IIRC


True, if there was one thing the PPI cannot do it is phase control. This is my only gripe, luckily phase can be switched manually. For the $$, Im not complaining, In my mind its only a $50 option at best.


----------



## chuyler1 (Apr 10, 2006)

Just an FYI, the PPI unit can accept speaker-level inputs and I believe it will sum the inputs too. You just have to lower the sensitivity and then select the right input options. So as far as integrating with factory units, it should be on par with the RF360 except that you have to do everything manually.


----------



## npdang (Jul 29, 2005)

Ok, went home and double checked. Yes, the PPI has 6 channel output and so does the RF 3sixty.2. No, the PPI doesn't have line level inputs. The sub channel on the RF unit is fixed at LP only, with 10 bands of parametric eq. Sub out also includes a subsonic filter. The RF is fine for a 4 way setup if you split the center channel output, similar to the PPI.


----------



## npdang (Jul 29, 2005)

t3sn4f2 said:


> Thanks, Yeah I've been keeping up with that thread, asking other things about it too, I assume that the preamp on that unit must be pretty good but wanted to make sure.


I've been following that thread and still don't understand how it works? It maybe better, or it maybe another Hall/Stadium/Rock type of dsp. Knowing JBL though, I'm betting it's going to be something good... just wish they'd give us a little hint about how it works.


----------



## 02bluesuperroo (Oct 31, 2006)

cvjoint said:


> How did you evaluate the voltage outs of the PPI? In my experience both the h701 and the Eclipse cd7000 units had stronger outs when you have to adjust the volume on the PPI to get rid of some of the background noise (12-15 steps or so IIRC). The usable range of the pre-outs is therefore subpar to most 4v and 5v units, even an analog PPI xover I used before.


I have the voume on the PPI set at 0db for the subs and mids and -4db for the tweets. I have no noise at all and my unit is EASILY putting out double the voltage as my 4v Kenwood deck. (Estimate based on gain setting)



andthelam said:


> I too have no noise and my volume is set at 0db subs and -3db tweets and mids.


Ditto.



npdang said:


> Ok, went home and double checked. Yes, the PPI has 6 channel output and so does the RF 3sixty.2. No, the PPI doesn't have line level inputs. The sub channel on the RF unit is fixed at LP only, with 10 bands of parametric eq. Sub out also includes a subsonic filter. The RF is fine for a 4 way setup if you split the center channel output, similar to the PPI.



The PPI doesn't have line level inputs but since you can attenuate the line level by 12db you can still splice RCA ends onto your speaker wires from a stock head unit and plug it into the DCX.


----------



## DaveRulz (Jun 22, 2006)

02bluesuperroo said:


> The PPI doesn't have line level inputs but since you can attenuate the line level by 12db you can still splice RCA ends onto your speaker wires from a stock head unit and plug it into the DCX.


That's what I did, works beautifuly.

Also, +1 on the no noise with the output all the way up.


----------



## cvjoint (Mar 10, 2006)

Hmmm...I guess only some PPI's have this problem  I'm sure your guys' units are dead quiet because if they were like mine you couldn't live with the volume all the way up.

BTW I am not saying anything about the sensitivity adjustment .25v to 3v IIRC. That one had no effect on background static.


----------



## bdubs767 (Apr 4, 2006)

P880PRS + PPI DCX, may be an unbeatable combo


----------



## chuyler1 (Apr 10, 2006)

npdang said:


> Ok, went home and double checked. Yes, the PPI has 6 channel output and so does the RF 3sixty.2. No, the PPI doesn't have line level inputs. The sub channel on the RF unit is fixed at LP only, with 10 bands of parametric eq. Sub out also includes a subsonic filter. The RF is fine for a 4 way setup if you split the center channel output, similar to the PPI.


I just read through the instruction pdf for the RF 360.2. No where does it say that the center/sub channels can be used as anything but center/sub. That means you could not use them for a 4-way system since the center output is only mono (unless you would be fine with mono midbass). The PPI DCX on the other hand poses no limitations on outputs.

The PPI DCX does not have speaker level inputs but the sensitivity can be adjusted to accommodate a high-level input. I believe it mentions this in the crude instruction booklet. It gets a point off for ease of installation though since you would have to place RCA ends on your speaker wires instead of just sticking them into a set-screw.


----------



## npdang (Jul 29, 2005)

I don't understand how you would get a stereo output from the PPI for a 4-way when it has the same number of outputs as the RF unit? Or are you suggesting that you pass 2 channels to a midbass, and then route that to an amp for the sub?


----------



## 02bluesuperroo (Oct 31, 2006)

cvjoint said:


> Hmmm...I guess only some PPI's have this problem  I'm sure your guys' units are dead quiet because if they were like mine you couldn't live with the volume all the way up.
> 
> BTW I am not saying anything about the sensitivity adjustment .25v to 3v IIRC. That one had no effect on background static.


For my subs I am on Sensitivity .250v 0+ db attenuation and for Volume I am on 0 db

For my mids and highs I am using only one input. .780v 0+ db attenuation on that input. For volume my mids are at 0 db and my tweets are at 5.0 db for the left tweet and 4.0 db for the right tweet


----------



## chuyler1 (Apr 10, 2006)

npdang said:


> I don't understand how you would get a stereo output from the PPI for a 4-way when it has the same number of outputs as the RF unit? Or are you suggesting that you pass 2 channels to a midbass, and then route that to an amp for the sub?


Yes, exactly. Set a LP X-over point of 400Hz or something on the subwoofer outputs. Then you can split the outputs with Y-adapters or use an amplifier pass-through. Just about every amp on the market can handle a HP 50Hz crossover and LP 50Hz crossover. So you can easily get 4-way. 

You can't do that with the RF 360 because you don't have 3-sets of stereo outputs. You can't do that with the Pioneer PRS880 because it won't let you LP the sub channels that high. Of course you sacrifice time alignment on your midbasses but it sure beats dishingout 600-1000 for a Clarion DRZ9255 or Pioneer P9.


----------



## npdang (Jul 29, 2005)

But won't your processing on the midbass channels affect the sub as well?


----------



## chuyler1 (Apr 10, 2006)

Yes...but I don't see that as a problem....you just won't get time alignment and you can't play with the crossover points from the driver's seat. But if you need to boost 160Hz it won't affect the sub, if you need to boost 20Hz it shouldn't affect the mids.


----------



## jearhart (Jul 28, 2006)

you could just do what i am doing and xover the sub with the head unit. unless of corse you are trying to do a 4way with an oem HU which would be hard to pull off with any processor.

the only things i would change on the PPI would be phase shift, 4way active ability i.e. 8ch of output, and digital input(VERY optional) but when you look at the $165 i spent on it i really cant complain about anything


----------



## cvjoint (Mar 10, 2006)

chuyler1 said:


> Yes...but I don't see that as a problem....you just won't get time alignment and you can't play with the crossover points from the driver's seat. But if you need to boost 160Hz it won't affect the sub, if you need to boost 20Hz it shouldn't affect the mids.


yeah but what if you need to boost the mids at 100hz with a fairly wide q?

I used the ppi 4 way but I used the sub out on the head to run the subs, 4 way only makes sense this way.


----------



## boarder124 (Mar 16, 2006)

I belive that if you add a external crossover like a audiocontrol eqx you can keep the use of the time alignment, because i will be using the eqx for my mid-midbass crossover, The distances they are apart from my head a minimal, so that leaves me with the abbility to still use the ta on my tweets and subs and not to mention I will have 13 more bands of eq to play with on each side.


----------



## Thoraudio (Aug 9, 2005)

bdubs767 said:


> P880PRS + PPI DCX, may be an unbeatable combo


actually, I was thinking the 8250 + the DCX would be an unbeatable combo.... if the DCX had been available at the time, I wouldn't have gotten rid of my 8250 for an 860.... 

but I just *had* to have h/u control...


----------



## quality_sound (Dec 25, 2005)

chuyler1 said:


> Yes, exactly. Set a LP X-over point of 400Hz or something on the subwoofer outputs. Then you can split the outputs with Y-adapters or use an amplifier pass-through. Just about every amp on the market can handle a HP 50Hz crossover and LP 50Hz crossover. So you can easily get 4-way.
> 
> You can't do that with the RF 360 because you don't have 3-sets of stereo outputs. You can't do that with the Pioneer PRS880 because it won't let you LP the sub channels that high. Of course you sacrifice time alignment on your midbasses but it sure beats dishingout 600-1000 for a Clarion DRZ9255 or Pioneer P9.



I could swear when I read the manual it said you can turn the center in a second sub out for stereo sub output. I'll look again.

Also, someone said you couldn't run all the outputs with a single pair of inputs but you can, with either the high or low level inputs.


----------



## chuyler1 (Apr 10, 2006)

*MY COMPARISON AFTER WORKING WITH BOTH*
I have the PPI DCX-730 in my car and have been tinkering with it for over a month now. I haven't had any buttons break like some have complained about but every time it boots up one or two vertical lines on the display do not render. Which lines is different each time but it is usually one that makes it hard to read the difference between L and R on the display at a quick glance. The DCX has no limitations when it comes to having 6 output channels. You can choose any configuration you want. The problem is setting up that configuration, and identifying it quickly. 

As others had mentioned, making adjustments on the high frequency spectrum is tedious. It allows you to make changes in 1Hz increments and if you hold the button down it gets progressively faster. When you release the button it continues for a while before stopping. To go from 3000Hz to 5000Hz usually takes about a minute and you can't do it while driving unless you want it to take about 5 minutes. Furthermore, each time the frequency changes the unit hicuups and cuts the sound for a split second. It sounds really weird when you are running quickly through frequencies. A better approach would be to just wait until the user releases the button to apply the change. If you wanted to compare 3000Hz to 5000Hz you would have to save each one in a pre-set and switch between them. There will still be a slight hiccup when you select one but at least the change will be instantaneous.

Another problem with the DCX-730 is poor documentation, especially in the area of input sensitivity and output volume. After much trial and error I have figured out that you need to set your input sensitivity slightly above the output of your head unit. For example, if you have 2v pre-outs you should set it for 2.1v. If you set it below your pre-out voltage the unit will clip when you approach full volume. I also noticed that only the front inputs have a wide sensitivity range, most likely for speaker-level inputs while the rear and sub inputs only go to something like 2.5-4v (I don't remember the exact number but I was surprised when I couldn't go farther). Now for the output volume there is another limitation. Anything close to 0db will cause clipping at full volume and severe hiss. I have found -12db for midbass/bass and -18db for highs is required for decent response without a noise floor. The problem of course is that this results in about 1-2v of output for your amps instead of the typical 4v or desirable 8v. I have my gains set much higher than I have ever needed to set them which again doesn't help the noise floor one bit.

So in conclusion, the PPI DCX-730 gets an A for configurability but a C for S/N ratio and output voltage. Sound quality is still great as long as you can put up with a little hiss.

Astral on this board has the RF 360 and I helped him with some tuning the other night. We used his laptop to connect to the 360. Obviously you need a laptop or palm pilot to do ANY configuration so making changes while driving isn't exactly possible. However, you can make changes so quickly if you had a palm pilot you could easily make an adjustment in the 30-60 seconds you spend at a traffic light. Through the GUI interface you can quickly disable/enable channels and adjust volume. You can set crossover frequencies pretty quickly also but you are limited to 12db OR 24db for each channel. So if you want a 24db HP crossover on your mids you will have to use a 24db LP crossover on it also...there is no mixing and matching and you can't choose 6db/18db butterworth/linkwitz like you can on the PPI. The sliders used for the volume and EQ are nice for a visual representation of the current tuning setup but they were very difficult to change by 1db increments. You cannot drag them so I would click what I thought was a 1db increase and it would boost it 3-6db instead. I'd have to go back and forth until I got it right and by that point I lost my reference of what I was changing. The good thing is that the sound isn't interrupted when you make a change. It smoothly transitions allowing you to hear your change in realtime. The bad news is that there is not back button or way to quickly switch between two different configurations. You can save your configuration but it takes upwards of 30 seconds to reload it and during that time you don't have any sound.

I didn't help Oleg hook it up but I did notice you can set the volumes of channels at full output w/o clipping and there wasn't any noticible hiss or noise floor. The sound quality was about the same as far as I could tell. Both units were connected to factory radios so neither were going to blow us away with 24-bit DAC quality sound.

In conclusion, had the PPI DCX not been available or been more expensive, I would not hesitate to purchase a RF 360. It has enough features for one to set up a 3-way (tweet/mid/sub) system and dial things in from the driver's seat. It falls short in crossover options and the GUI could use a little work but the whole package is very appealing. However, I am still happy with my DCX. I have learned to deal with the quirks of using buttons to make changes and having the additional crossover options as well as a parametric EQ has already come in handy. I have dropped the noise floor to a reasonable level by lowering the output volume of it and thankfully my amps don't mind playing with high gains. I also like having the option to make changes whenever and whereever I am through the attached display. Perhaps if I had a CarPuter with bluetooth in my dash the 360 would be more appealing in that light. But anyway, both are capable units once you get past their quirks. Neither are the end-all solution to tuning but they will get your system to a point where it sounds great and hopefully at that point you won't need to touch either interface again!


----------



## Need-sq (May 26, 2007)

Would it make any sense/difference if you placed a high quality line driver (don't know, maybe AC matrix?) in the chain after the DCX? This way you couold boost up your pre-amp voltage to whatever you wanted? or would this just be adding unneccesary components into the mix?


----------



## Mless5 (Aug 21, 2006)

chuyler1 said:


> I also noticed that only the front inputs have a wide sensitivity range, most likely for speaker-level inputs while the rear and sub inputs only go to something like 2.5-4v (I don't remember the exact number but I was surprised when I couldn't go farther).



I have to disagree. I have 3way set around 9.4v.


----------



## chuyler1 (Apr 10, 2006)

Ok...I stand corrected. Perhaps only one of them goes to 24v then. I'll check it out on my way home.

I don't think adding a line driver will really help much. It will give your amps a higher voltage input but it can add noise just as easily as the PPI does. If I had one lying around I'd give it a shot but I wouldn't buy one specifically for this purpose.


----------



## 02bluesuperroo (Oct 31, 2006)

The input voltage range is different depending on whether or not you have the input attenuated by 12db. Maybe this is the difference you're experiencing?


----------



## chuyler1 (Apr 10, 2006)

That's probably it....hmm, I wonder if I have that set or not...I haven't checked recently.


----------

