I decided to do my audio install in 3 steps. The first reason was to acknowledge my time constraints. The second was to get a more accurate impression of the improvement brought on by each step. So my steps were:
- Install my new JL 600/6 amp with the OEM speaker system
2. Install the new Morel Ovation II speakers and crossovers in the front doors
3. Install new Jehnert 200 mm speakers in the underseat enclosures
So I will try to document my issues and results on a step-by step basis.
1. Amp install. I purchased a JL 600/6 amplifier new on ebay for approximately $380. I also purchased a wiring harness kit for $75 plus shipping. The install was easy with the only issue being why the harness did not have an additional foot of grounding cable so I could ground to the same point as the battery. Finally I accepted grounding onto the point on the LR fender. Not the ideal solution. In my experience, multiple grounding points only raise the probability of hum later on. The additional cost to be able to ground the power at the same location as the battery could not have exceeded $1.00.
Results in comparison to stock: Not much difference at all despite the higher quality amplification quality. The JL amp did afford the possibility to increase the gain to the underseat woofers, with some sonic improvement.
2. Install of Morel Hybrid Ovation II mids ,tweeters, and crossovers in the front doors. Price on Ebay was $449. $25 additional spent on wires/connectors to avoid cutting/splicing the BMW wiring. Install was a bit of a PITA finding a suitable location in the door panels for the crossovers. I had to solder a splice in the wiring to the mids and the tweeters, which surprised and disappointed me. Why not just make the lead wires a few inches longer? One issue was mounting adaptors for the 4 bolt Morel speakers on the factory 3 bolt mounts. After considering alternatives I spent $55 plus shipping to obtain machined aluminum adapters, and I am glad I did this. The results undoubtedly saved me a lot of time.
Results were great. Replacing the OEM speakers with the Hybrid Ovation II snapped the soundstage into focus and eliminated the fuzz. I was pretty happy with this for several weeks, and more-or-less forgot about the mid-bass.
3. A lot of work has been done with Kaigoss and others on the mid-bass support that can be expected from various speakers in the underseat enclosures. After a lot of review it appears that the Jehnert 8" mid-woofers are as good as it gets. What can I say, these speakers are pretty pricey for an 8" woofer, especially when you consider that you are not getting a cast frame construction in the deal. Reality is that the Jehnert looks fairly inexpensive to make, and it only has a 1 inch voice coil to boot.
I thought these speakers were pretty pricey in the US, but I would be able to get around this by purchasing them in Germany (where they are manufactured) or India. What I finally found out was that the purchase price in the US was as good as it gets, so I bought them here for $459 for the pair plus the spacers, delivered to my door. Cost of this step also includes $25 for wiring/plug adapters for the underseat woofers, to preclude cutting the BMW wiring harness. This makes step 3 marginally more expensive than step 1 or step 2. Results of Step 3 were less dramatic than step 2, to be truthful.
So TIC approaches $1500 with lots of my labor. Luckily, I work very cheap. The best bang for the buck was Step 2, but I do not have sufficient data to show how this would work using the stock amplifier in lieu of the JL 600/6.
I hope my observations are helpful to others trying to decide what must be done to improve the BMW Hi Fi system for acceptable listening. It is too bad that the improved components that I have installed are not BMW standard equipment.