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      08-01-2010, 08:01 PM   #1
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Talking UK E92 Base audio system upgrade - 5.25" Rainbow/Earthquake/Genesis/Audison

I've posted this originally in the UK Technical section but thought I'd copy it here as I think a few of you might be interested in this.

Some of you might know that for the last year or so I've been trying to find the time to do a wholesale upgrade of the basic audio system in the E92. I was tired and frustrated with the low quality (to me) of the standard system and I desperately wanted to get it up to the standards that I needed. The basic system in the UK is the same as the very base system that you guys have in the US in the 2010 model cars - ie. 4 midrange units and 2 underseat subs, but no tweeters.

There's been a huge amount of work done and the work has been undertaken in multiple stages. I had some great info from Technic and VP Electricity that helped me figure a few things out later in the install. I can't go into everything as it would just be too much info, so the shortened (!) version is thus -

The standard system has four midrange drivers and two bass units underneath the front seats. There are no tweeters as most of you will know. The midrange units in the doors are 4" in diameter, but the main problem is the shallow depth of the door cavity. In reality, the maximum depth of a speaker unit can only be 50mm, without requiring some modifications and custom made mounting rings. Tweeters can be installed in the standard locations in the internal mirror cover, or they can be mounted on the A-pillar but that requires some major work.

The underseat subwoofers are a nominal 6" in diameter, although the aperture can fit an 8" subwoofer, with Earthquake making a direct-fit replacement (albeit requiring a 12mm MDF spacer ring to give enough clearance)

To interface into the OEM headunit, which normally only provides speaker-level outputs in the base configuration, I needed a DSP interface unit that would convert the signal to a line-level version suitable for the amplifiers. I also wanted a top quality 4-channel amplifier to power the front speakers and the new subwoofers. At this time I had decided to retain the standard rear speakers.

I had decided on using the following components -

Rainbow CS210 4" components (midrange and tweeters) for the front speakers
Earthquare SWS-8 2ohm subwoofers for the underseat locations
Rockford Fosgate 360.2 DSP
Diamond Audio D700 amplifier

All this lot was installed first time round as a temporary measure, just to see what it sounded like. And, if I'm honest, it was crap Too bright, a bit thin, no integration between the midrange and the underseat woofers. In fact, there was no integration anywhere at all. The setup just didn't work as I was intending and if anything the stock system sounded more complete. Infuriating to be honest!

I took the whole system over to a brilliant guy called Anil Woograsingh, who owns Creative Car Audio in Hornchurch, Essex. He's a one-man band with a small shop, a small area out back to do installations, and an awesome ear with the most spectacular eye for detail and care

He took a listen and agreed with me that the amplifier was probably the prime suspect for the thin and bright sound. He also thought the tweeter position in the OEM location was far too close to the seat and therefore too bright and direct with no sense of space or imagery.

We started playing around changing the amplifier to a Genesis amplifier, which immediately brought major dividends in sound quality. We also concluded that part of the problem was that we were still using the OEM amplifier built in to the iDrive unit. In effect, we were amplifying an already amplified signal, and a crappy one at that too. Consequently I got hold of Autologic and asked them to recode the vehicle order data on my car so that it was configured for the HiFi option (ie one up in the options list from the base hifi). The HiFi spec for the iDrive disables the internal amplifier and changes the speaker-level outputs into a line-level output at 5V, and a balanced differential output at that (which means there's no interference on the signal sent to the amplifier)

The front stage was still not right however so I started investigating how to improve the integration between the subs and the main speakers. I worked out that a bigger set of 5.25" speakers from Rainbow would fit diametrically, but were about 6mm too deep. Anil worked out that he could make a set of angled, shaped speaker rings that would push the midrange drivers into the cabin, keeping them in the standard location, and therefore would allow the drivers enough depth to fit in the door. When I mean fit, I really mean JUST fit - there's enough space on the passenger door to just slide a cigarette paper between the speaker and the dash! Anil also built the tweeters into the A-pillars, with a very neat bit of fibreglassing to make them look like factory

The underseat subs were resealed with a form of epoxy for an airtight seal, the original Rainbow 4" speakers I had bought relocated to the rear doors, and a whole new brace of amplifiers from Genesis installed with a new DSP unit from Audison for greater flexibility in configuration.

All the electronics and amplifiers were relocated to under the boot floor - surprisingly there's just enough space and height to allow for the Genesis amplifiers to be installed, without losing a single cubic centimetre of boot space

Final list of equipment -

Rainbow CS230 5.25" component speakers, front stage
2x Earthquake SWS-8 2Ohm subwoofers
Rainbow CS210 4" component speakers, rear stage
2x Genesis Dual Mono amplifiers (front stage, subwoofers)
1x Genesis Stereo 60 amplifier (rear stage)
Audison Bit One DSP unit

The result?? It sounds AMAZING Utterly detailed, clear and spacious, with a beautiful midrange sound that makes vocals just project out into the car. The bass is really good, not 12" sub deep perhaps, but because they are located under the front seats you can really hear every single bass note as clear as day. Even the rear passengers get a great sound with the 4" components located there.

I've directly compared the system in my car to a car with the top Individual system from BMW, and the sound in my car is just so much fuller and detailed. It's really night and day and being a music lover I'm really satisfied with how it's turned out

Of course, all this comes at an expense, and even if I just cut it down to the final system without the steps inbetween, the whole system is just shy of 3,500 ($5,500) for the components alone. Installation if it were done in one go would probably take three days, including the custom fibreglassing and tuning/setup of the system. I also took the opportunity to retrim the A/B/C pillars and headlining with black Alcantara Previously it was the standard SE grey cloth trim from BMW which I hated, and now it's just beautiful

So, an expensive install but looks OEM to the uninitiated, and sounds like a really top-end home hifi. Anil has done an utterly amazing job, and his eye to detail and the care and attention he lavishes meant that every single screw and clip has been correctly done up and replaced where necessary. There is not a single rattle from any of the panels he has taken out (and it's virtually the entire cabin!). I cannot recommend him highly enough. He can do everything from a cheap Parrot bluetooth installation to a full-blown custom glassfibre competition creation.

I'll be bringing the car to the London/Essex meet at Sytner Harold Wood on Sunday 8th August if anyone wants to come by for a listen

Pics below of the speakers and the retrim of the A-pillars (and steering wheel). You can see just how little space there is for the 5.25" speakers! I'll take a couple of pics of the boot install tomorrow so you can see how it all fits underneath the boot floor.

Links to the equipment as follows -

Anil Woograsingh - http://www.creativecaraudio.co.uk/

Genesis - http://www.genesiscaraudio.co.uk/
Rainbow - http://www.rainbow-car-audio.de/
Earthquake - http://www.earthquakesound.com/
Audison - http://www.audison.com/

B-Trim (retrim) - http://www.b-trim.co.uk

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      08-02-2010, 04:47 AM   #2

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Thanks for that detailed write up.

I've got the HiFi Business stereo (pre '10 US base system/ one upgrade from current base system) which includes a separate amp and the tweeters. If I was going to do an upgrade on that and keep the cost to around GBP500/$800, any suggestions?
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      08-02-2010, 05:05 PM   #3
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Drives: 2002 325i Sedan
Join Date: Aug 2010
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Thank you for the good read. It was cool to read where it started, the intermediate stage that should have been an improvement, and then what the final results were.

Good equipment list - great install - and awesome tuning potential with the Bit One.1. I may purchase one of these models in the future - trying to figure out exactly what I would want to do. Thanks for sharing.
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audio, audison, bit one, components, dsp, earthquake, genesis, rainbow, subwoofer, tweeters

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