Okay, been a while but I managed to find a bit of time over the xmas break to complete(*) my audio install.
*Audio installs are never truly complete.
Quick recap and report.
I was very unhappy with the combination of the Focal 200mm component speaker system and Focal miniature classD amplifier that I had bought and installed. The main issue was the boomy and uncontrolled bass at ~120Hz and the lack of significant bass output below ~80Hz.
Steps taken since then:
1. First job I did was to install a Match 5 mdsp mkii amplifier in place of the Focal amplifier. The main aim here was to use the DSP capabilities of the Match amplifier to EQ the bass. The results were interesting. I'd say the Match amplifier is generally superior to the Focal even without the DSP enabled. It provided tighter bass response and really clear mid-range from the same Focal 200mm speakers. That said, things were improved further by adding a notch filter at 120Hz with a 4-5dB cut and Q of ~1.5.
I also experimented with adding a bass boost from ~150Hz and then a high pass filter to remove the lower bass content. What found was that the 200mm Focal speakers in the door produce very little output below 80Hz. In fact, if you just set a HPF to remove all the content below 80Hz, they sound much better. This is consistent with the frequency response plots that I posted earlier in this thread.
While I was at it I EQ'd the rear speakers (cheap JBL ones) to get their character to better match the front speakers. Honestly, I'm sold on DSP. You can fix all manner of issues once you have a decent multichannel EQ.
At this point I had a better sounding setup but it was obviously light on any real bass. I'd say this reinforces the idea that the 200mm Focals are not buying you much over the 160mm ones (or indeed 160mm ones from Alpine or whoever). In short, if you want clarity, get a 160mm set of component speakers. The extra 40mm of cone diameter from the 200mm Focals is not going to buy you more bass in the door. Probably also explains why neither Alpine or Focal really push their 200mm speakers for the T6.
2. Anyway, next job was to install the sub. For this I bought a prebuilt under seat enclosure and fitted an Audison 10D speaker. The reason I went for the 10D was that I could then use the Focal amp's two bridged outputs to drive the separate coils on the Audison speaker (the 10D is a dual voice coil model). If you're not limited to a Focal amp or similar, go for any 10" speaker you like.
Obviously question would be to ask why I didn't just use the sub amplifier in the Match amp? Basically I had the Focal amp and it will deliver 320W dual bridged vs 160W from the Match amp. To get the best from the Match while using the sub amp I'd also have needed to run a dedicated power supply from the battery. Using it only for four channels with no signal below ~80Hz meant I could use the existing supply from the Quadlock loom without worrying about over-current.
Fitting was, frankly, a pain. Inexperience on my part combined with the fact that it involves a fair bit of interior removal and cable routing meant it took me three 2 hour stints in the van to get it done correctly.
Key learnings:
a. The Focal amp will not auto-enable when using the line output of the Match amplifier to drive its inputs. You need to run a 'remote' cable from the Match amp to the Focal amp. I did not do this on the first attempt and was pretty despondent when I realised I had to strip a load of interior back out to run the addition cable.
b. I did have a the 50A feed from the battery under my passenger seat so found that a really convenient supply for the amp.
c. If you have heated seats, you might need to cut a notch in the pre-fabbed sub enclosure 'top' in order to get enough slack in the seat cable (so you can run the seat all the way forward and back).
After all that was done, and I'd enabled/configured the line out on my Match as a sub output to drive the Focal amp, I finally got a chance to test.
In short, it sounds great. Real bass. Minimal (or at least much reduced boom/bloom) in the bas notes which means it's far less fatiguing to listen to. The lack of bass through the front and rear speakers means they sound far better than was previously the case.
Summary of kit used below: It has to be said though that this is a real 'round the houses' install. The choices I made were based around trying to make best use of the parts I'd already bought.
1. Focal 200mm component speakers in the front - Needless to say, I'd not recommend these.
2. JBL coax-ial 160mm speakers in the rear - These sound fairly dreadful without EQ (really mid range shouty sort of sound). They are okay once EQ'd. I'd be okay using them again provided I have EQ. To be fair, I have them mounted in the roof so there's very little volume behind the speaker which will do nasty things to it's performance. Probably most speakers would be challenged in this location.
3. Match 5 mdsp mkii amp - I really rate this amp. It's smaller than the Focal amp and includes ~same output power with 5 channels and two line outs all with comprehensive DSP. If you were happy to have a bit less bass and were happy to route direct power from the battery (not really that hard a job) then I reckon it'd probably be fine to drive the sub too. Sure, list price is way above the Focal but I got mine second hand on eBay for only a little more than a new Focal amp. So, not the end of the world.
4. Sub enclosure and Audison 10D from Absolute5 - Install of the box was pretty easy aside from the slight trimming to accommodate the seat heater wiring. Speaker dropped into the box no issues at all. I'd say the speaker is pretty good but I'd guess most mid priced 10" subs would work just as well. Like I said, only reason to choose the Audison was to get that dual voice coil. Only complaint with the sub is that, due to under seat mounting, you do get a bit of haptic kick through the seat. This is actually pretty cool with dance/pop but feels a bit weird with more complex rock or acoustic music. This isn't really a gripe about the sub/enclosure though, just something to be aware of in any under seat install.
5. The Focal amp (4.320). It's fine. Probably a bit overpriced for the job I have it doing now but, like I said, I already owned it so wanted to use it. If I were to do the job again I'd buy any old amp off-of eBay and stash it under the passenger seat (there's loads of space).
What would I do differently next time:
1. 160/165mm door speakers. Probably take a punt on the Alpines.
2. Go straight for the Match amp.
3. Single voice coil 10" sub to allow it to be driven by the sub amp in the Match amp. When running the speaker cable from the Match to the sub though I'd also run a line level cable from the Match line output. This would make for an easy later upgrade if you wanted a bigger sub amp.
And that's about it. Hope this was useful to someone.
Ohhh, forgot to add, I set the xover for the sub/doors at 100Hz. I played around with anything from 60Hz up to 200Hz. 60Hz doesn't integrate well as the doors have started to roll off before the sub kicks in. 200Hz and you can hear where the bass is coming from. So, ultimately plumped for 100Hz though I think you can play around a bit more to find your own preferred sweet spot.
I didn't do a lot of EQing on the Sub itself. It works pretty well as is. All I did was add a HPF at ~40Hz since content below that is inaudible in the van so why stress the speaker/amp. As per the doors, reducing the content below the freq where the sub works best served to clean up it's overall sound quality too (and reduced rattles at high volume).
