German Audio Specialties E34 Passive Crossover Network

[StereoInstaller1]

Time for a whole new idea in how to deal with the sound in your BMW.

As most of you already know, we build a full line of subwoofer enclosures and amp racks for most early BMWs: E21, E28, E30, E34 and E39, with th E46 coming soon. We now have over 30 products, but this post is all about something I have been dreaming of for years and years...a 10 speaker passive crossover network.

What this does is allow the stock BMW speakers to perform at an incredibly high level of sophistication, clarity, detail and dynamics.

This is our prototype:



We will be offering this product as an introductory piece for the next few days. The price on our site will be $350, with more expensive options added later. Expect a more finished look than this, of course, as with all of our early prototype pics.

The crossover uses a blend of different crossover slopes and frequencies to extract just amazing performance form very little power, an inexpensive $100 4 channel amp will make your car sound better than you would ever believe.

More soon, including a first for us, an installation video. Watch for it!

Luke

[StereoInstaller1]

30 views and not one comment?

[raziel310]

Interesting....alot of ppl from BFC prolly would love this!

[StereoInstaller1]

Yessir, lots of people over there talking about it

[raziel310]

Once u get the 1st kit up, I'll bite into it w/ the sub box, right now I got a few stuff goin on so I can spend alot of $$ to upgrade my e34 =p

[StereoInstaller1]

Once u get the 1st kit up, I'll bite into it w/ the sub box, right now I got a few stuff goin on so I can spend alot of $$ to upgrade my e34 =p

Good to hear! I swear, the E34 10" is just brutal, I cannot believe the pressure this thing makes and SO clean!

LMK when you are ready, we have 10" and 12" in stock.

Thanks!

Luke

[Jean]

Nice job Luke! Care to share what crossover points/slopes you ended up with for stock e34 speakers? No l-pad needed for the tweeters? nice!

I won't need this only because I use IDQ stuff in mine, but if it was still stock that would be another story. I hope this takes off and you have lots of buyers though!

[golde30]

i would consider this for my e34, but my e30 luke box already blew out my eardrums and I'm deaf now. kthnxbye

[Van Westervelt]

I will likely buy into this with another custom e34 touring hidden sub box as well once I start working... :)

[StereoInstaller1]

i would consider this for my e34, but my e30 luke box already blew out my eardrums and I'm deaf now. kthnxbye

Drag you ass up here, my E34 will fix your damn ears!

BTW, you gonna be up early enough for us to do some cosmetic tricks on your install?

Thanks for the comments, guys. Curt, when you get closer, we will nail it down.

Nice job Luke! Care to share what crossover points/slopes you ended up with for stock e34 speakers? No l-pad needed for the tweeters? nice!

I won't need this only because I use IDQ stuff in mine, but if it was still stock that would be another story. I hope this takes off and you have lots of buyers though!

Jean, I thought you knew...this is 100% open source...just as soon as I break $10/hr.

Late E34 drivers are 4 ohm tweeters, 8 ohm 2" dash mids (BEEFY!) and 4 ohm midbass. All 4 in the rear are 4 ohm. If you had to pick whatever impedance to have anywhere in this car and what size, these drivers are just about ideal.

4 ohm tweet, so nice and bright, 8 ohm mid so it can be nice and laid back, 4 ohm midbass so it thumps nicely...winner, eh? It really is a sweet setup.

Of course different BMWs are different, so we can change the board to suit pretty much any BMW setup. So, if you happen to find yourself driving an E39, E92, whatever...this can do all of them. Plan to tackle some MBZ, Mini and Audi too...this is German Audio Specialties, right?

Since we know what parts are in your crossover, we can tell you what to change, or you can send it in. Since every bit of everything will be made public, you can do it all on your own, or copy our designs. If stuff changes, everyone should be able to find out what to change, right?

What we have no plans to do is offer a "kit". No thank you. Hopefully Parts Express will offer a parts kit, but the boards themselves will go through many changes and options, including special editions, built in looking "custom trim" kits. Personally, I say this thing is WAY sexier than any amplifier, so I want to show it off. My trunk is M5, I will put it in the left pocket. It will have a plexiglass face and LED illumination. Sort of a "big" look, hopefully.

Other cars will be dealt with shortly: E36, E39, E38, E46, E60, X5, whatever. As you noticed, we have plans. Hopefully we can make some sales so we can pursue our plans, right? I would like to see us have magazine ads and employ maybe a dozen people. This is too niche to ever get "big", but this is a MAJOR hassle saver for install shops and DIY people. We hope to have a dealer network too, along with guys like you...oh by the way...Jean, you DO remember you will be installing one of the first ones, right?

The midbass is lowpassed at 650Hz @12db/oct. The impedance shunt is the only electrolytic cap we used, and it is bypassed with a 400V metalysed poly cap. We ended up preferring the 12db slope to have a bit of a bump, so could cross the midbass as low as possible.

I am sure you noticed we used all Air Core "Perfect Lay" coils clearly designed to eliminate any chance of stray EMI or crosstalk. I hate stray noise, this should fight off anything. If you notice in the pic, there are two crappy coils. They will be replaced, we just could not get the correct value in time, so we had these made. They are not in the signal path.

By the way, we will be offering a 6.5" mounting kit soon, possibly with our own woofer. I want an old school beefy midbass like the old Fosgate Audiophile and no one seems to make one anymore. The crossover point could be changed if needed, and can also be run active, or just bi-amped, as all speakers have separate inputs. As it is, the stock drivers using the stock mounts do have a bit of "thwunk" if you listen carefully. Clearly, it is because they are mounted to the plastic kickpanel...not what you wanna call ideal, but the rest of it totally eclipses this little weirdity. The midbass is absolutely stellar. Kick drum is just insane, bass guitar has incredible detail...all the sudden, you hear the bass guitar frets. Kick drum pedal muting is absolutely clear, and doublets/triplets/quads are just so clearly defined...it is nice, it really is.

The midrange is where we spent most of our effort. We tried just about every slope, every point, all kinds of different alignments, all by ear. We will be finalizing the last tweaks in the next couple of days with the RTA.

Honestly, the RTA was nice, but pointless. Every single piece did exactly as suspected. Take a close look at the drivers, it is pretty obvious they are pure function instead of pretty packages...but they are all very nicely made.

Back to the little midrange, we have 850Hz highpass, 12db/oct, Bessel alignment. The little bump at the crossover point seemed to be smoother integration. The "bounce" from the glass was audible with 500hz test tones, but not so much a 900Hz, so there is some weird phase issue I just did not want to hear. The output was not even remotely linear. So, even though the driver will do it, the logical solution was to raise the crossover point.

Hopefully my goal here is obvious: a nice musical balance first, getting a nice fat midbass, punchy midrange with great power handling yet nice and smooth, along with sweet, elegant highs...oh lord, the detail this thing makes is unreal. I was aiming for as little overlap as possible. I listened to the little 8 ohm mids for a bit, ran some sweeps...the things could easily do 300Hz.

I chose the higher crossover point and the little bump based on what I heard. I want just enough heft to be able to hear excellent sound at 75MPH with the windows down and sunroof popped open...but not thick and murky when listening in town or parked, so the balance between the 4 ohm midbass and the 8 ohm midrange has to be taken into account with the phase change between the kick panel and the dash...oh, and wait, now we have yet ANOTHER phase angle between the mid and the tweeter!

Blending the tweeter and the midrange is like herding cats.

So, what ended up was a blend. We did 7Khz high pass, 12db/oct with an 11 watt 22e as protection. If you are careful to not allow ANY signs of clipping, it is very listenable (if a bit bright) with no protection or Lpad. That 4/8/4 setup is awesome! We added the protection and raised the crossover point several times over the course of several tweaking sessions. We are thinking it may yet need to be a bit calmer...but when I added a 2db LPad, I hated it. The little mid is low passed (Again, you noticed the caps, right? 400V Metalised Poly! Who does that?) at 6500, 12db/oct with a traditional Linkwitz/Riley alignment. We thought that being our "focal point" sonically, it needed the most time. It is a very strong front stage. The detail and clarity are far superior to pretty much any set of components out there, you basically have to do full active with serious drivers to do as well! I mean, this really does kill most anything I have ever installed short of that level of insanity.

The rears got a basic 5Khz 12db/oct Linkwitz/Riley. Did you look at the tweeter angle? Dear god, you could not ask for a better location or a nicer driver! Rear stage in this car is critical. I am gonna poke a stick in all of the audiophile eyeballs here, but I say that it is better to listen to . I say the overall ability to sink into the music and really enjoy the sound is enhanced by having such a lovely rear stage...electronica? LOL..absolutely mesmerizing, stunning, brilliant. Rap? Holy CRAP, how did that little woofer do THAT? Jazz, blues, classical, whatever...musically, this is phenomenal by any standards. Absolute accuracy...well, we shall see. I say having this level of sonic balance is very much worth it not being absolutely smooth, but I bet a proper EQ will nail it down nicely while preserving the "energy" of the sound.

[Jean]

Luke - that is way too much to read ! lol j/k. Good work man!

[StereoInstaller1]

Cliffs: 650Hz, 12db/oct low pass for midbass

750 to 6.5Khz, 12db/oct bandpass

7Khz and up for tweeters. Again, 12db/oct.


Rears are a simpler 6Khz 12db/oct 2 way

Various slopes are used to achieve balance.

Light bulbs (AKA calibrated variable mechanical thermistors) protect the tweeters from DC offset, they simply light up to blow off voltage to save the tweets.

[StereoInstaller1]

Guys, the final version:

[Gregs///M]

Fantastic idea Luke, the vintage BMW world needs this!

[AndrewBird]

Can't wait to get mine!