Need advice for new Polk system - comp spkrs, amp and sub
Hello out there in CP - my request is kind of detailed - but I'm sure one of you out there can help me.
Just bought a 07 Acura MDX (with the Nav package) which comes with a 10 speaker fancy audio system. Sounds great (and plays the DVD-A discs which sound cool) but overall is underpowered IMHO and uses factory lightweight speakers. I want more power overall, more mids and low bass. I'm also spoiled with crisp Polk tweeter highs - which I had in my Honda Accord (about to be sold - more on that later)
Here's what I'm planning for an upgrade --does it make sense?
Head unit: Keep the stock one - it's integrated with the HVAC system for the MDX and would be a PITA to replace. Another complication: It's a data link system where the headunit does not control the volume but instructs the stock amplifier via a data link signal chain. The main system amp powers the interior speakers directly while sending a line level signal to a secondary subwoofer amp, mounted within the stock sub enclosure on the passenger side rear panel.
What this means is that I cannot tap the signal before the stock amp and have to utilize the speaker level signal post-amp for front stage and the line level signal for subwoofer. Happily though, there are no separate signal wires for midbass and tweeter so no summing will be needed.
Front soundstage:MM6501's - woofers in stock locations in doors w/ tweeters either in dash stock location - or finding new location to drill new hole in upper door panel. I did this for my older Accord and they still sound great after 11 years.
Rears fill: Leaving oem speakers (they have 6 1/2 drivers in doors and 3" mid/high drivers pointed forward from C pillars. These are decent -- running off the factory HU/amp - so they run of of juice - but I would just be using them for fill and for making rear seat passengers happy.
Subwoofer: - the MDX comes stock with a sealed 8" DVC sub in the rear quarterpanel -- complete with a .25 cu ft custom enclosure. Powered by a seperate 25w stack-of-playing-cards-sized amp mounted right in the enclosure. This amp is fed from main stock amp by line level signal - but I'm guessing its a lowpass signal so I can't use it to drive the rest of the system (also I would lose my fader if I did this). It's a paper resin woofer and I noticed it only plays normally when the balance control is centered. When it's fed to just right or left channel from the HU balance control, the amp stops playing. My first time with a DVC sub -- so I'm not sure how that works. I'm planning to ditch the factory amp and sub and put in new Polk MM840 in same location -powered by new amp.
Amp: Planning to replace the factory amp with a Polk unit -- probably a 500.4 which I found factory refurb for only $199.
1. I've read about bi amping the comps in front -- how would I go about doing that? Since I don't need the rear channels of the 500.4 I could send them to the woofers and send the amp front channel power to the tweeters? I believe the amp provides the crossover settings to eq the 6501's, correct?
2. On my Accord, I was running a passive crossover network (caps and coils build for me by local audio shop back in the day) which ran my MM5251's (or whatever they were called back then) and a 10" free air sub all off the same Kenwood 40w x 2 amp. As I remember, the highs, mids and mid/bass were fed to the front comps and the lows to the sub in back. It all worked and sounded awesome. (I was actually tempted to rip it out of the Accord and put it in my new MDX -- but MDX doesn't have a trunk for the free air sub and plus I can put 6 1/2" woofers in the doors rather than the 5 1/4's from the Accord. So the new owner will get the best audio system in a 92 Accord in this area!) Could I run the Polk MM840 the same way off the 500.4 (for instance with the tweeters on their channel) since the highs would be going to the tweets and just the lows from those channels to the sub? How would that get wired up so all the ohms and the frequencies are correct? Would the inboard crossover settings in the 500.4 manage that set-up? If they won't, I will just run the 6501's off the front amp channels (with a HP set to cut out the lows below 60 hz or so) and bridge the rear channels to go to the sub.
3. Assuming the above setup ould work, should I get the DVC MM840 or the regular one? What is the difference?
4. Would the MM840 be OK in the smallish (roughly .25 cu ft) enclosure? Pretty sure the depth of the woofer is ok - but I see from the MM840 specs that it would like more cu ft of air in an enclosure. Granted I'm going for sq, not trying to rattle neighbors windows, so wondering if I could just live with it. Another option would be for me to go with another brand of sub -- some make a shallow-mount 8" which is both designed for a smaller enclosure AND because of it's design takes up less airspace in the enclosure. BUT....it's not a Polk and I'm kind of brand loyal.
5. Will I need to clean up the spkr level signal (and get rid of all the HU eq and processing) with a box like the JL Cleansweep? I've read on MDX forums that other have not had to mess with this - but I'm unsure. Thoughts? Any MDX 2nd generation owners out there perchance?
6. What gauge power wire should I run to the 500.4?
Thanks again for the help