Creating a new speaker is a balancing act that requires compromise at every stage of the design process. Balancing measurements with listening tests, efficiency with power handling, enclosure size with low bass, etc. In fact in the last few years the biggest challenge has become finding a balance between art and engineering. From the perspective of the speaker engineer, this comes down to, "How do I make that drawing of a speaker that marketing just gave me actually sound good."
Inverted dish shape cones are the latest in the current marketing trend in speakers. These cones are becoming popular because they provide a seamless appearance. From the art perspective this is about as good as it gets. Simple, smooth, and lots of room for logos and eye catching color. From the engineer's perspective, this is a nightmare. The shape isn't always as strong as a conventional cone, and in fact to make it work you actually have to attach a small conventional cone to the back side. This means extra weight, manufacturing problems, and potential high frequency and efficiency problems as well.
Still most companies are market driven; that's just the nature of the economic beast. So engineers do their best to find ways to solve these problems and perhaps even to find benefits in the new design. This is what the people at Alpine appear to have done.
The SPR-176A is really beautiful from a marketing perspective and well designed from an engineering perspective. Here are some examples of its balance in terms of art and engineering:
Art: Beautiful dished cone with a vapor deposited aluminum coating.
Engineering: Lightweight paper undercone minimizes mass, large diameter, lightweight santoprene edge reduces mass and minimizes "Edge Hole" frequency response errors.
Art: Simple elegant cast frame with a minimum number of spokes.
Engineering: Three spokes eliminate basket ringing, basket is designed to center the frontplate for faster production speed, and the spider landing diameter is very large allowing for a high excursion and linear suspension.
Mounting the speakers has also been thought through well. Many cast frame speakers have large flanges that make them very difficult to mount in factory holes. The Alpine woofer has an outside diameter of 6.5" and a mounting diameter of 5.75", making it fit standard holes perfectly. Its depth of 2.75" is a bit much for compact cars, but it should drop in to your SUV just fine.
The silk dome tweeter is simple, easy to install and has the smallest possible size for a 25mm dome (i.e., it doesn't look like an afterthought when mounted in your door). There is a provision for both flush and surface mounting via a unique mounting ring that tightens down to the door panel by threading onto the outside of the plastic housing.
The crossover could be seen as just another variation on the rectangular box theme. However its shape is smooth and elegant; it is made of a dark smoked plastic that is nearly completely opaque, giving it a very high quality (price) appearance. Inside the crossover strikes the same balance. Good quality components (mylar caps and air core inductors), and a simple and functional design (12dB highpass with polyswitch protection, 6dB lowpass).
So now the question is, "Do they perform as well as they look"?
With all of the obvious attention to engineering as well as cosmetics, the answer of course is yes.
The testing was done on a MLSSA system using ACO pacific 100kHz. mics., a class A lab amplifier, and ultra high grade cables. The speakers were mounted in an EIC baffle accurate to 200 Hz. and frequencies below 200 were tested by the near field method and spliced to the 1 meter responses. Parameters were also tested using MLSSA using the fixed Mmd method. All of the response graphs were exported to LEAP to make their graphic output higher quality.
The on- and 30 off-axis responses are very respectable. The crossover features a selectable 0, -3 dB and -6 dB tweeter attenuation. Setting this to -6dB gave a very flat response on the test baffle (both on- and off-axis. The variation was +/- 5 dB mostly in the 6-9kHz. region, which is better then most component sets in this price range. Looking at the separate woofer and tweeter responses you can see the primary cause of the response error is caused by a sharp spike at the top end of the woofer's response. This is typical of dish cones speakers, however it is very well controlled here. The efficiency of 86 dB is a little low (probably because of the extra mass from the cone design) but certainly high enough to produce respectable SPL with a medium sized amp. The impedance curve shows a very nice smooth response that won't give your amplifier any problems.
The Thiele/Small/Benson (see sidebar) parameters gave yet another sign of the quality engineering that went into these speakers. Many car audio speakers are designed for efficiency only and the loading of the speaker into the car is not considered. Ideally, a speaker designed for car doors should work just like they were in an ideal enclosure. This means that the Qts of the speaker is much higher then a speaker designed for use in an enclosure. This seems obvious, but it just isn't very common in most of the products in the range. Alpine obviously understands what it takes to make a speaker sound good in a car.
It's pretty obvious that I liked these speakers. They are beautiful, well designed and have really good performance. I would put them in my car, and that's not something I say too often. Nice job by the engineers (and marketing guys) at Alpine.
Listening
For this month's subjective listening test, we tested Alpine's fiendishly good looking, all new Type-R component speakers. For those of you that are not familiar with Alpine Electronics, COME OUT FROM UNDER THE ROCK! Alpine Electronics is one of the world's leading mobile electronics system suppliers. Alpine specializes in an integrated platform concept for mobile multimedia, with research and development facilities in Asia, Europe and the U.S. And if that's not enough, here's more: The company is owned by Alps Electric Co., Ltd., one of the world's premier manufacturers of electronic components for computer, communications and car electronics equipment. So, in other words, Alpine's the Shiznit.
Now that we have a little background on Alpine the company, let's look at the SPR-176A, 6-1/2" component 2-way speaker system. The tweeters are a 1" soft-silk dome that can be mounted either flush or on the surface of a panel -- and the tweeters will swivel up to 15 degrees to allow aiming.
Todd Van Zandt, chief cook, bottle washer and sometime Product Promotion Manager for Alpine, told me that the woofers for the SPR-176A were modeled to be "mini" subwoofers. They have a rugged cast aluminum frame with a large magnet structure and a vented pole piece. The cones are of a unique construction. They feature aluminum coated polypropylene co-molding to improve rigidity and damping.
The 2-way crossover is asymmetrical in design with a 12dB high pass for the bottom of the tweeter roll-on and 6dB for the woofer roll-off, including tweeter protection and level adjustment. I suspect the woofer has a natural roll-off at the crossover frequency, allowing Alpine to use just the first order crossover slope to achieve a proper match.
The test vehicle I am using is a 2000 Ford F-350 Super-Duty Crewcab. The Ford has 6 x 8" holes in the doors, so I planned on using the Metra 82-5600 speaker adapter to fit the 6.5" round Alpine speakers into that space. But no, the SPR-176A's woofer is a cast framed 6.5" that can make real bass. So I had to go ask Bigfoot (a.k.a. Pat Holdaway, head installation guru at Speaker Works and my brother, who will probably kill me for calling him "Bigfoot") to cobble up some speaker mounts that would hold these behemoths.
Once we got the speakers into the doors, I was nicely surprised to find that the tweeters are fairly consistent and have a smooth off-axis response. This made it rather easy to get solid imaging with a minimum amount of time spent "aiming" the tweeters. I played with the built-in crossover attenuation, but found that -0dB was the best sounding.
I used eight different albums and nine songs to fill in my opinion on these speakers: Lenny Kravitz, 5, "I Belong to You"; 10,000 Maniac's, In My Tribe, "Peace Train"; Ramsey Lewis, "People make the World Go'Round"; Jennifer Warnes, Famous Blue Raincoat, title track; Schubert, Symphony #9, "The Great"; Shoanna Z's album Racism Exposed, "NBC, ABC, CBS, CNN, AKA Left Wing Trickery" and "Quotable Quotes"; Rage Against the Machines, "Know your Enemy"; and Metallica's, "Ride the Lighting."
I started out with the 10,000 Maniac's "Peace Train." This track opens with a deep repeating 30Hz bass drum kick. While the SPR-176A's did not reproduce the fundamental note, you could hear a nicely defined mallet strike on the "skin" of the bass drum. The female lead vocal is round, smooth and enjoyable. The upper treble is smooth too, but lacks shimmer. Which is a theme that runs throughout all of the listening. The midbass toms and bongos have excellent detail and tightness.
So I had to get to some male vocal to compare with. Listening to Lenny Kravitz, "I Belong to You," I find the male vocal has the slightest bit of sibilance (sibilance: spitty or over emphasized "s" sounds in words.) As is my practice to track down sibilance, I jump to get my Jennifer Warnes "Famous Blue Raincoat" (FBR) recording. "FBR" is a great recording with which to listen and test, because Ms. Warnes voice is completely exposed in this recording and she hangs on every "S" in each word. If you want to know whether a speaker has a bump in its response curve in the 4 or 5kHz range, this is the track that will show it because of the "S"'s. Jennifer Warnes is mic'd very closely and you can hear all kinds of little noises in her singing and breathing.
The SPR-176A's did not show-up to be overly sibilant in the reproduction of the singing voice. In fact, I find that the high frequency detail and high frequency extention are the main weakness of these speakers. The bass, midbass and midrange are really excellent on the Alpine SPR-176A's. The toms and other percussion are nice and fat tonally; and skinny time wise. A good mix of what you want in this frequency range.
On Shoanna Z's breakout rap album the deep bass extension is quite remarkable through the SPR-176A when I play "NBC, ABC, CBS, CNN..." which opens with a powerful 40Hz bass line. The vocal layering and clarity are excellent. I also listened to "Quotable Quotes" from this album to test the spoken male voice. The Alpine SPR-176A's were very rewarding with three-dimensional placement of the person speaking and separation and depth of the musical background track.
Next, I plugged in some classical music from Telarc's 20-bit recording of Schubert's Symphony #9, "The Great." This speaker has smooth and realistic midrange, bass and midbass responses. The string bass has good authority and definition. The violins, violas and cellos were great! The brass section is good and solid, but lacking in the upper frequency overtones, leaving the brass a little too "brassy" sounding.
On jazz, I found the SPR-176A's had good ambience on percussion and the drum kit. On most of the tracks I found the piano reproduction to be a little "boxy," and small sounding. Yet the room ambience was always well above average with all of the musical tracks that I selected.
From smooth easy listening to METAL! Rage against the Machine's "Know your Enemy" is fun and energetic on the reproduction. The male lead vocal is a little thin sounding and could use more chest. Metallica's "Ride the Lighting" is reproduced with fast and detailed double bass and excellent guitar playback.
The Alpine SPR-176A component speakers do so many things good in the bass all the way to the midrange, that it is hard to complain about the high frequency deficit. I enjoyed my time listening to the Alpine SPR-176A's and with a retail of only $280.00 a pair, they are a deal.