the helix p-dsp is a great unit. i have not had any problems with it during its operation for the past year i have had it installed besides misunderstanding that when you install a new version of the software on your computer, the next time you connect to the DSP to change anything it will push the firmware to the DSP and all the output channels will have this crazy super loud noise that will blow your speakers up (i popped $40 worth of tweeter). all you need to do is make sure your amplifiers are off during this update, and no problems.
there are only a few drawbacks - the EQ could have a better resolution (like .25db steps). the eq could have spots to manually change the frequency rather than just having it set 1\3 octave (the c-dsp does both of these things i think). the menus are easy enough to get around, i wish there was a way to set independant left\right EQ and crossover, then link the channels and do small tweaks to both channels without messing up the left\right information.
for example, if you set 1000hz to +1 for right, and -3 for left, then link the channels and decide you would like it set to 0 for right, and -4 for left, so you are looking at the left midrange page (after you linked channel 3 (left midrange) to channel 4 (right midrange) and move the slider on 1000hz down 1db so it should now read -4 and this is good. when you click on channel 4 and look at 1000hz, it will also read -4 instead of 0 where you wanted it! its a pain because you cant change two channels at once or link all the channels and adjust the eq overall if you have already done left\right independant EQ. but that is a VERY nit-picky issue.
the ONLY other thing that bugs me - and this is a software thing - is that the resolution of the software window is stuck at 800x600 and can not be re-scaled at all.
if you have a netbook with LESS than 800x600 resolution, you may as well not even turn it on because you will get all the EQ cut off at the bottom of the screen. most people will not have this problem - but i feel compelled to mention it. i will also mention - that EVERY piece of software that i have used with EVERY DSP has this same problem - so its nothing that helix is doing different.
but the DSP is strong, small, simple, and fairly inexpensive solution to DSP with all the bells and whistles (besides a remote).
all im waiting on is to swap the helix into my wifes golf, and put my arc audio PS8 into my gti. luckily, there is a harness you can buy for the helix products that integrate with german cars (like the golf) and it has a harness that plugs right into the back of the head unit and the DSP will work perfect
very cool.
i ended up putting my image dyanmics IDQ6 in her doors because the paper foam gasket keeps the cone from touching the door card if they get moving a lot. i also trimmed off all the extra ribs and such from inside the door card to give me a smidge more clearance.
so for all the people wondering - the plastic speaker baffles have one tragic flaw. they are exactly the same depth as the OEM speaker... but the oem speaker is not mounted to the surface like an aftermarket speaker. so the speaker flange is +1\4 inch, the surround is +1\4 inch, and the excursion is on top of that. so in reality, the height of this aftermarket speaker baffle should be a half inch more shallow so that the cone can not touch the door panel!!
i wish manufacturers would use foresight in speaker mounting provisions... *sigh*