Installation Feature: The Rug Doctor’s Retro 1974 Porsche 914

The Car
Rod, known as Rug Doctor on the Talk Audio forum boards is one of our top stalwarts on Talk Audio. His moderator’s moniker is ‘Legend’ and he has made over 18,000 posts since August 2005. The car in question is his lovely powder blue Porsche 914, manufactured in 1974.
The car’s install has evolved over time and has had Infinity EMIT tweeters as well as exponential compression-driven horn loudspeakers in the past. Now, Rod, upon being congratulated, that his system seems simpler than it has ever been in the past, said, ‘Thank you. It might look simple, but this is the most complicated this system has ever been! Five separate amp channels, analogue active processors, each speaker on a different amp and a separate battery bank…. I have soldered no less than twenty-six silver RCA plugs for this system!’
So, it’s sexy ordnance, well put together so let’s learn more&;
Rodders, with the Porker at the Car Audio & Security first round EMMA SQ Sound Off, 2013.

Source
With innards made by Clarion for McIntosh, the MX5000 Audio Control Center is even more deliciously retro-looking now than when it was made, anachronistic as anything back in the day. It is a full CD-era digital unit and even decodes HDCD, making it rare as my Sony SACD in car player! But a lot sexier-looking.
The simply beautiful meters next to the classic head unit install are the MPM4000 analogue power meters and are really about showing signal level in dB as a general indicator as to signal cleanliness and health. It’s one thing to use a peak clip lamp or even an oscilloscope, but like a recording or live sound engineer, Rod knows that nothing is quite as useful a tool as a decent VU meter for looking as music changes from recording to recording. Incidentally, they do look cool as a cool thing, in Iceland. In winter.
Lovely culty McIntosh goodness.

Processing
Now, Rod was a bit sardonically amused when I revealed that the USD signal processors, three of them in classic 19 inch studio/road case rack mounting width for professional audio use, were nevertheless considered a bit cheap and semi-professional in studio circles, despite their legendary status in car audio as conversion items. Then he revealed that none other than ‘Amp Doctor’ (and thus in fact general circuit-board consultant) Mr. Gordon Taylor had been through them, replacing op amps and some other components. As a result, items that were chosen for using converted for 12V use because of their terribly useful internal voltages, as well as a good 108dB signal to noise ratio in the first place, have now been turned into very serious processors for in-car use, indeed.
He has two USD Audio SW-30b 30-band equalisers, with short throw faders as they are ‘One Rack Unit’ or 1U high and between them an active USD Audio SW-3x Stereo/Mono crossover with mighty power for the wee job it is doing with the Velodyne subwoofer. Here is the heart of tuning for the system of course.
USD Crossovers and equalisation.

The Velodyne subwoofer system has two accelerometers, one on the cone, one on the chassis and its own DSP:

Cabling
With much silver solder, as described above, the RCA cords were all custom cut and hand soldered. A neat job for a craftsman and a royal pain if you are not. But our Rod certainly is, and he took pleasure in creating just what he needed.
Front Stage Only
With the car’s layout, there really isn’t much cabin space, nor boot cubic to mess about with, so the concept of any rear speaker was just not happening. Besides, as a true SQ aficionado, Rod wanted the full front-stage-including-bass thing that only a very few sound off heroes have achieved in the past. He didn’t want any rear sound. Mark Turner is one such notable, from Enjoy The Drive, but very few non-professionals have ever done this.
Yes, we know that bass is supposed to be omnidirectional but you can feel sound pressure gradients with you hair follicles as well as your ears and you CAN tell the bass is normally coming from the rear. Yes, on occasions, I have heard a car where the bass is just allowed out a brief scant before the rest, by clever use of time alignment systems and thus allows the real psychoacoustic effect to kick in, making you really believe it is all one. Sonic Frontiers’ Lee Tomas is a genius at that stuff.
But our Rod is a damn talented man in many directions and did all this himself.

You can see that it is all on-axis&;

Apart from the beautifully custom-built bass enclosure, there are two very neatly fabricated speaker pods, made to fit the car and drivers exactly and to offer the KEF Uni-Q loudspeaker drivers a perfectly on-axis delivery to the driver’s ears. The idea was to reduce reflections and create as HiFi an experience as possible.
Sub-bass provision
Velodyne make some bonkeracious home woofers like the DD18+ and I have been lucky enough to test most of the UK available ones for Home Cinema Choice magazine. But the single-woofer-only intended Velodyne driver-plus-included DSP unit in Rod’s car was a cult item and is no longer made. It needed a minimum of 300 watts of clean amplification and back when it was made, that was very much before we HAD clean-class-D amps and was considered a bit of a tall order. As a result, they were discontinued and now there is a small community who buy and sell these. And Rod’s was second hand!
With the use of an accelerometer on both cone and chassis, the idea was that the DSP could remove any extraneous vibration or cone movement from the subwoofer, caused by it being in a moving car! Sounds amazingly impossible but the cult was born through sound-off success. And Rod loves his one.
Amplification
What were once McIntosh amps are now a trio of Soundstream amps, from their big shiny Rubicon range, imported these days by PPA (who you can call on 020 7993 8889 and who also import HiFonics, PPI and a slew of other fine kit) Despite a definite recent return to form, these also retro models were very carefully chosen by Rod for the job and all are pretty much over-sized for what they need to do, thus offering a great slice of headroom, or power reserves left for peaks, even in loud passages of music. This all adds to the fidelity of the sound.

Sound
The complex nature of Rod’s system means he was in the Advanced Unlimited Class at the SQ sound off and as his car was built solely for pleasure and the competitions were entirely a secondary thing, he did incredibly well for a car not built as aimed at an EMMA sound off.
He came away with a trophy and some degree of glory. I was there to award him the cup and he was chuffed as anything! I personally love the work he has done and the whole evolution of the system if you go through the thread is both edifying and educational. Some lovely things have been said to him and quite right so. It’s a lovely retro car and a lovely system.
Just goes to show that a Talk Audio Moderator walks the walk as well as talking the talk!
LINKS:
Rod’s excellent build thread, (running at 46 pages long at time of writing) and starting with the previous incarnation of ordnance he installed in the Porsche&;
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A slideshow of the pictures of Rod and his car at CAS in Spring 2013
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