Alpine SPG Backstory

Recently reviewed on Talk Audio magazine the Alpine SPG-17CS component loudspeakers turn out to have been the result of a literally epic R&D effort at Alpine in Japan. Adam Rayner caught up with Atsuhiro Takeda of Alpine to find out more.
First of all, I was fascinated to learn more about Atsu himself. He’s Alpine’s Southern Area Manager and is one of four ASMs at Alpine. He is, by his own admission possibly the most geek-struck of them and spends a slice of his time on Talk Audio’s forum. He has a product knowledge that goes deep into the tech zone and regularly speaks with engineer types in Japan as after all, Japanese is his mother tongue.
Atsu came to the UK from a year in Japan after growing up in the USA with his dad who was being a company warrior for the Sansui electronics company as an engineer and sales bloke. When his dad came to the UK, Atsu came with and lived in North London near my folks’ home in Harrow as Sansui was based in Greenford at the time.

And here’s an odd one. Sansui kit was wicked quality and I bought a reconditioned top end cassette deck in the Tottenham Court Road for £300! I then bought three SM-100 amps and a seven band graphic EQ for use with it but couldn’t work out how to hook the third amp up to be used for sub-bass into the woofer I had found in a bin at an audio company and had re-coned at Wembley loudspeakers. I went to Sansui and managed to get the attention of two engineers, one Japanese. I kind of interrupted them and recall with such clarity that they argued briefly while one was half-way up the stairs about the 4k7 resistor I would need in the speaker level feed to cross out the mids and highs in the signal fed to the bass amp.
It has to have been Atsu’s father! Small world huh?
So when Atsu got here he had an American accent but now has a pukka Norf London one, very like mine! Recently returned from a visit back to Japan, he had a whole bunch of stuff to relate about the SPG speakers and how they were developed, as well as why. He met up with an engineer – Mr. Tada – in Tokyo in ‘Electric Town’ an area called Akihabara and legendary world wide. Makes our old vision of the Tottenham Court Road look like a Sunday Market stall!
The Carton
It might seem minor but the product had to look sexier in the shops. So, instead of the old style of packaging, the SPGs are in a new carton. This has extensive instructions and details all printed on the outside and has no need for further printed material to be included. Very Green. If you want a print version to keep, you can always download and print from the website.
Incidentally, I found a simple error on the pre-production carton I had which has now been corrected and checked on the stock versions. It was a detail about connecting the split passives up – an error of illustration. I don’t know how many boxes were destroyed but in true Alpine tradition, this was not allowed to go out in a wrong condition. (And I gather they had spotted this before I did in any case.)
Instead of a sealed box and polystyrene packing, it’s all recyclable now, with card inserts and posh plastic covers that can go to make drinks bottles afterwards. Along with a gate-opening box, the shops can display them in cabinets or upon shelves without unpacking. Merely a shop-display issue but germane to your deciding they look cool enough to invest in. 

Cast Chassis
A specially tooled injection moulding was used, that is so precise it was right up against the limits of what the material can achieve. A very cunning shape that creates little dog-leg shaped air vents to the coil. This makes it less likely for debris to end up in the voice coil over time, especially ferric particles as they have to do a 90 degree bend to get through and if any iron filings or the like get in there, they are held hard sideways by the magnetic flux. This locks them inside the cooling vent shape and means they cannot get into the gap itself. Very elegant, very clever and meant to be durable. (Unlike one brand of speaker that shall go nameless that was tested while they were researching, that was found not to be ‘car audio’ at all and to absorb moisture in its cones until they disintegrate after two years they reckoned!) It sounds tweaky but it’s actually a pat pending item and crucial to the speakers’ designs. Very rigid, very strong and inert and no ringing.
Cones and Their Evolution
There were around a dozen different Polypropylene cones tested, all with different amounts of Mica mineral loading from low percentage to high. Not only does this alter the sheen and visual appeal of the speaker but it also affects sound. In fact a different cone material make up was used for the 17cm speaker versus the 10cm one. They were being really picky at Alpine and I gather got some bleating from their cone makers! It took six months to finalise and even at pre-production it was changed as the engineers were not fully happy with the sound.
The High Frequency Transducer – Tweeter
The ten, thirteen and seventeen centimetre speakers all have a 20mm silk dome tweeter but proving what I have always said about six by nines being a crucially important kind of speaker, (despite their being a variety of driver you almost dare not talk about upon the forum due to ‘purist beliefs’) the big oval set gets a different 25mm driver. Not mad high end, as these are made to sell in big numbers but still a quality Silk dome.
On the grille front, the engineers used a gel CAD/CAM system to prototype shapes for an effective grille for the HFs. The idea was stylish yet able to be put under an OEM tweeter location with great proximity to the baffle above it. This loses less highs as you come out of the panel. Many tweeters that are placed in stock locations are horribly attenuated by their needs-must depth behind the panel. The skinny grilles on the SPG tweeters are both attractive but very close into the dome’s surface. I gather that Alpine bought LOTS of OEM panels of cars to test and check this in particular. Again, one big and famous brand that shall go nameless (different to the other one!) was found to have big tweeters that just didn’t work well in OEM locations.
Passive Crossovers
And here’s the tweakiest bit of ALL.
The humble audio capacitor. The best are arguably made by Elna and their ‘Silmic’ variety is so well made and fabby that Denon have a whole page on their website bragging about their use of Elna Silmic capacitors (called ‘Condensers’ in Japan by the way) inside their well respected beast-grade home audio products.

Alpine engineers tried thirty types and when it says simply ‘custom capacitor’ in the dealer guide when referring to the way the SPG series of speakers were designed, it failed to point out that even then the Alpine guys required Elna to make them a Silmic with a slightly different silk electrolyte inside it. Atsu even showed me a photo-micrograph of fibres of their silk versus what’s normally used. In all the years I have spent as a reviewer, I have never ever heard of a speaker maker specifying the very internals of electronic components and then getting them custom made! Hand matching is as tweaky as I have ever heard of before and this goes WAY past that. I also understand that a degree of closeness of the relationship between supplier and user was instrumental in getting this done.
All in all the story is long and convoluted and deeply tweaky but what it means is that the new series of Alpine SPG speakers is voiced especially for European tastes and is about as far from ‘off the shelf’ as it is possible to get.
I want to extend a big thank you to both Takeda-san and Tada-san for being such stalwarts that both got together in their own time in Tokyo to enable us to find out all about this stuff. It mightn’t grip you as much as my slightly OCD self (it’s been said!) but what it means is a set of speakers that punch way above their weight in both level and quality for the money charged for them.
In English. “Alpine’s SPG speaker series are jolly clever and jolly good!”
Coulda done it in ten words…….
And here’s where to click to see a funky cool slideshow in the newly imported gallery system. We LOVE this! If you go to the gallery itself from the menus above you can get at the fuller size versions of you want to nick any….
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