The Harman Kardon Affair

One of the reasons I got a 2.8 instead of a 2.3 was the “premium” Harman Kardon stereo system with “upgraded” speakers. Granted, it wasn’t the ONLY reason, nor was it the PRIMARY reason, but it was A reason. I have to admit that as far as stock sound systems go, I’ve heard worse. But I’ve heard better, as recently as the day I got my Z3, which is when I turned in my 1998 Ford Expedition Eddie Bauer with a Mach 460 stereo system. Without getting too much into an acoustics argument, the Harman Kardon system, well, how can I put it….. SUCKED.

I am not an audiophile. I am not a music hardware nut. However, I do enjoy my music, and I like it loud and I like it distortion free. The first clue that the HK was a POS was the rattling of the subwoofer enclosure. However, through my “investigation”, I found out that the HK amp was “tweaked” to produce 10% harmonic distortion. Now, I am not an audio engineer, but for something that is usually measured in FRACTIONS of ONE PERCENT, 10% cannot be good. Cranking the volume up supported this conclusion. The distortion was there, and life sucked.

The Amp has GOT to GO

In one of those fits I am famous for (hey, the car cost me quite a bundle with all the stuff I put in it, so I WAS frustrated), I took it to the folks at Tampa Bay Audio Sound, and they hooked me up with a couple of brand spanking new Alpine amps — an MRP-F306 and a MRP-F406.

Alpine MRP-F306 4 channel amp

MAX POWER (EIAJ)

75W x 4 (4 Ohm Stereo) 180W x 2 (Bridged 4 Ohm)

FEATURES

RMS Continuous Power (Watt) (at 14.4V, 20-20 kHz): 4 Ohm Stereo (0.08% THD) 30W x 4; 2 Ohm Stereo (0.3% THD) 40W x 4; Bridged 4 Ohm (0.3% THD) 80W x 2

Alpine MRP-F406 2 channel amp

MAX POWER (EIAJ)

90W x 2 (4 Ohm Stereo) 240W x 1 (Bridged 4 Ohm)

FEATURES

RMS Continuous Power (Watt) (at 14.4V, 20-20 kHz): 4 Ohm Stereo (0.08% THD) 40W x 2; 2 Ohm Stereo (0.3% THD) 60W x 2; Bridged 4 Ohm (0.3% THD) 120W x 1

Why two? Trunk space was a prime concern (or lack thereof), so any of the premium solutions that ate up trunk space were unacceptable to me. No 1000 watt amps for me. I wasn’t looking to win a BOOM BOOM competition, just clean, distortion free, loud music. Simple.

The Alpine MRP-F356, a 5 channel amp, would have sufficed, but it was BIG. The F406 fit nicely into the space the HK POS amp fit (marked by the red circle in the middle picture below), and the F306 was fitted vertically neat and tidy on an L board on the other side of the trunk with virtually no loss in trunk space.

The guys at Tampa Bay Audio Sound configured the F306 to supply only highs and mids, and the F406 to supply the bass (using a simple switch on the amps themselves).

Now, with this came some good news and some bad news. The good news was that the highs and mids sounded better, cleaner and crisper at high volumes. The HK amp was clearly very deficient in this regard. The bad news? The subwoofer popped, Bad. Of course you genius!!! A subwoofer rated at 30W was getting juice from the F406 which can pump up to 240W!!! Ok, so of I went into the quest for a new subwoofer.

The Quest for a Subwoofer

Putting a subwoofer in a Z3 is like trying to fit an elephant into a Jetta. Reading some more articles at MZ3.net and the Z3 message board I learned of many options, including custom enclosures and Bazooka tubes. None of these options sounded good to me (literally and figuratively) since the Z3 trunk is sealed and the lack of air put a serious cramp in the boom of the subs. Drilling holes in my brand new Z3 was DEFINITELY not an option for me, so on I went trying to find another solution.

I took apart the subwoofer enclosure (thanks to Robert Leidy and his article on Dissecting the HK Subwoofer) and took it to the folks at Sound Advice. They hooked me up with a couple of Boston Acoustics 5.5 ProSeries woofers (I had to pay for two whole kits which included tweeters and crossovers, which sucked) and installed just the woofers it into the Z3 subwoofer enclosure.

Something tells me that I could have gotten off a LOT cheaper than $400, but at that point all I wanted was a functional subwoofer that would fit in the stock enclosure. Money was not an issue (never is until the bill gets here… 🙂 I plugged the enclosure back into my Z3 and… Voila!

Ahhhhh, nice, neat tidy bass. Cool. I cranked up the volume all the way and it was now the tweeters and midranges distorting — the sub was cool as a cucumber. It was a good thing I padded all the contact points as specified in the Z3Bimmer.com Subwoofer Rattle article, since the extra bass would have certainly worsened the rattle problem. Once the proper insulation was installed, the rattling disappeared.

I cranked down the gain on the F306 a notch (to NOM setting) since I don’t listen to music that loud anyway (it was really hurting my ears at that point) and I reached a happy compromise — $1,000 later. 🙁

Upgrading the Front Speakers

With new amps and a new sub, the remaining speakers started to get on my nerves. Having seen the poor quality of the speakers I removed, I wanted the rest of those POS speakers out of my Z3 pronto!!! After reading several messages in the Z3 Message Board, I learned that to remove the tweeters on the doors, I had to remove the door panels. All of a sudden, the tweeters started to sound good to me. Nahhh, I didn’t need to replace THEM (wimp).

So I turned my attention to the kick panels in the front. An article in MZ3.net showed how easy it was to do, so I did the logical thing… took it to the folks at Tampa Bay Autosound to do it for me. 🙂

They replaced the front speakers with a couple of Rockford Fosgate 5.25″ coaxial 2-way speakers. Yes, I know, the stock speakers were component speakers and had no tweeter. However, I am the guy who turns the treble all the way up anyway, so a pair of extra tweeters didn’t bother me. And since I am not an audiophile, I had no clue what this would do to the sound balance in my car (ignorance is bliss…)

Actually, they sound pretty good to me. I can crank the sound up more, but the tweeters in the doors pop a little bit at the highest volume. Darn. I guess I’ll have to remove those door panels after all. Maybe some other day, but not today… 🙂

Upgrading the Rear Speakers

Turning my attention to some easy-to-replace items, I focused on the rear speakers. Removing the covers revealed a couple of 4″ component speakers (again, no tweeters here). Removing the covers was relatively easy. On the Y2K 2.8, the speaker grills and covers are held by five plastic tabs. You can pop a little door on the base of the roll hoops and you will see the top tab holding the cover to the plastic wall of the car. With a long screwdriver you can push down on that tab and pop the cover off.

WARNING: Do this at your own risk. I broke the little tab on one of my covers, although it didn’t seem to mind too much when I put it back. Don’t blame me if you brake your precious little Z3…. 🙂

I took my car over the folks at Tampa Bay Autosound and they hooked me up with a pair of Sony Xplode XS-F1020 4″ two-way speakers. We tried some SAS and some Alpines, but the tweeters wouldn’t allow the grills to be put back on. The Sony’s were a good choice since they had recessed tweeters which did not add anything to the size of the speakers themselves. No drilling or cutting of any kind was a goal of mine, not to mention a depleting budget made the Sony’s a good choice at $85 for the pair, installed. WOW!

Leave the Door Panels Alone

Which brings me back to the “popping tweeters” in the door panels. The folks at Tampa Bay Autosound put in some other kind of crossover that filtered out more of the mids and lows, sending more of the highs to the door panel speaker to address the popping sound. Seem like it took care of most of it. Only when I crank it ALLLLL the way up (and my ears start to bleed) do I hear some popping, but even at the loudest level I use it (which is doing 90Mph with the top down) they sound great. Besides, leaving those door panels alone is worth a lot to me… 🙂

Upgrade Summary

BMW’s “premium” sound system is, in my humble opinion, disappointing. They could have done better.

However, this is the ONLY thing that I can find fault with in an otherwise very, very, very cool car.

In summary, this is what I did:

Replaced Harman Kardon amplifier with a pair of Alpine amps

Replaced stock subwoofer speakers with a pair of Boston Acoustic Pro Series 5.5 woofers

Replaced front footpanel speakers with a pair of Rockford Fosgate 5.25 two-way speakers

Replaced the rear speakers with a pair of Sony Xplode XSF1020 two-way speakers

Filtered out all mids and bass going to the doorpanel speakers

The choices in speaker brands were mostly driven by price and fit into the car. The Rockford Fosgate speakers cost me $85 for the pair plus $20 install fee, and the Sony Xplode cost me $85 for the pair, installation included. For that price, you can’t go wrong! The Boston Acoustics Pro 5.5, on the other hand, cost me $400. Too pricey.

The system as a whole sounds good to me. No, I will not be competing in any auto shows, but it sounds a heck of a lot better than the stock system, virtually no modifications to the car at all, and 99% of my trunk space is still available.