npdang
03-02-2007, 01:39 AM
A big thanks to Breezyjr who donated both the Alpine z18w and the Rainbow Platinum 7" mids! :D
Please excuse the poor quality photos:
http://diymobileaudio.com/pics/7pics1.JPG
http://diymobileaudio.com/pics/7pics2.JPG
Nearfield frequency response comparison:
http://diymobileaudio.com/pics/7comp.JPG
Yellow - Rainbow platinum
Red - Alpine z18w
Teal - Peerless 830883
The Scan-Speak revelator based Alpines clearly have the best low end extension. A smooth 2nd order rolloff at 80hz should mate perfectly to a subwoofer. With cabin gain you could expect flat response down to 20hz. Very nice! Ignoring the artificats of nearfield measurement, on the top end we can see smooth extended response out to 8khz.
The Rainbow plat tends to be a bit droopy on the low end, and you can see it begins it's rolloff much earlier at about 200hz. We can also see 2 strong breakup nodes from the aluminum cone at 6khz and 9khz.
The Peerless is a bit droopy as well, although it's rollof doesn't start for another half octave below the Rainbow plats. There's also a bit of a peak at 3khz, and then a relatively smooth drop down.
Peerless 830833:
A well designed and executed driver, as evidenced by the Klippel tests. I especially like the open cast basket, dual copper shorting rings above and below the pole piece, solid metal phase plug, and the open flat spider. All the true markings of a modern, high end driver. And even better, it's so readily affordable.
Looking at the Klippel analsysis, the bl curve is fairly good. Relatively flat plateau, with good centering but somewhat assymetrical. Cms curve has a noticeable forward offset. Le curve is quite good and distortion analysis shows it to be significantly low. Perhaps not the best example in the Exclusive lineup however, especially when compared to the 4" driver. Also the cone material is uninspiring, appearing to be an untreated paper/nomex blend with a poly dustcap. The peak on the top end lends an aggressive, raspy coloration to the sound if not filtered. Still, great midrange clarity just short of the best hard cone drivers and the best in this roundup with the Alpines right on it's heels.
xmag: ~6mm
xsus: ~7.5mm
http://diymobileaudio.com/pics/peerless830883/ts.JPG
http://diymobileaudio.com/pics/peerless830883/klippel.JPG
http://diymobileaudio.com/pics/peerless830883/dist.JPG
Rainbow Platinum:
A gorgeous looking driver with an aluminum cone and polished chrome phaseplug. The motor is especially appealing to look at, although it's a bit of a guess as to what's inside. The driver gives the appearance of a rear vent, however there is none. There are also some small holes under the spider for venting. Not as open as I'd like to see but understandable for a driver designed for use in a car. No shorting ring as evidenced by the Le curve below, and the use of a tall cupped spider is somewhat of a rarity these days and a small surprise in a driver this expensive.
Looking at the Klippel analysis, the BL curve is excellent and by far the best in this roundoup. Textbook parabola shape, perfect centering and symmetry. Cms curve looks to have excellent centering, but with very poor symmetry. Le curve is unremarkable.
One thing to note is the Rainbow plat had exceptionally low mechanical noise. Better than even than Peerless Exclusive which is quite good already. Lowest xmax of the group however (not taking into consideration coil offset), and poor low end anechoic sensitivity. When used in a car door I could see the bass being a bit lean, but perhaps cleaner due to the early rolloff and the fact that most doors tend to have significant resonance issues in the 200hz region. I found the midrange clarity to be similar to the Seas L18RNX/P, which is to say very good, and close in performance to the Scans.
http://diymobileaudio.com/pics/plat7/ts.JPG
http://diymobileaudio.com/pics/plat7/klippel.JPG
http://diymobileaudio.com/pics/plat7/dist.JPG
Xmag: ~5.5mm
Xsus: >10mm
Alpine z18w:
Based on the Scan-Speak revelator, albeit with a remarkable markup. The worst Klippel performance in this group, although excellent Le curve. Bl curve is your textbook parabola, although severely offset in the forward direction and slightly assymetrical. Same with the Cms curve. Could possibly just be a poor sample, or not. Basket does not use the same "grasshopper" style as the Revelator, and is far more obstructive. Again, understandable for a car driver. Nice terminals though, and the only driver to feature a pole vent. Another interesting thing is the driver is coated on both sides, unlike the oem unit which is either untreated or treated only on the top side. I can't hear any audible difference, but then again I didn't have both drivers side by side to compare. Still the most unique, and advanced cone material of the bunch.
T/S parameters are much better suited to use in a car door, at the expense of overall driver efficiency. Clearly, the easiest driver of the bunch to throw in a door and get good results out of the box. Highest mechanical noise of the group by a large margin. For the money, I find it hard to recommend over the oem unit.
http://diymobileaudio.com/pics/alpinew18z/ts.JPG
http://diymobileaudio.com/pics/alpinew18z/klippel.JPG
http://diymobileaudio.com/pics/alpinew18z/dist.JPG
Xmag: ~5mm
Xsus: ~10mm
Please excuse the poor quality photos:
http://diymobileaudio.com/pics/7pics1.JPG
http://diymobileaudio.com/pics/7pics2.JPG
Nearfield frequency response comparison:
http://diymobileaudio.com/pics/7comp.JPG
Yellow - Rainbow platinum
Red - Alpine z18w
Teal - Peerless 830883
The Scan-Speak revelator based Alpines clearly have the best low end extension. A smooth 2nd order rolloff at 80hz should mate perfectly to a subwoofer. With cabin gain you could expect flat response down to 20hz. Very nice! Ignoring the artificats of nearfield measurement, on the top end we can see smooth extended response out to 8khz.
The Rainbow plat tends to be a bit droopy on the low end, and you can see it begins it's rolloff much earlier at about 200hz. We can also see 2 strong breakup nodes from the aluminum cone at 6khz and 9khz.
The Peerless is a bit droopy as well, although it's rollof doesn't start for another half octave below the Rainbow plats. There's also a bit of a peak at 3khz, and then a relatively smooth drop down.
Peerless 830833:
A well designed and executed driver, as evidenced by the Klippel tests. I especially like the open cast basket, dual copper shorting rings above and below the pole piece, solid metal phase plug, and the open flat spider. All the true markings of a modern, high end driver. And even better, it's so readily affordable.
Looking at the Klippel analsysis, the bl curve is fairly good. Relatively flat plateau, with good centering but somewhat assymetrical. Cms curve has a noticeable forward offset. Le curve is quite good and distortion analysis shows it to be significantly low. Perhaps not the best example in the Exclusive lineup however, especially when compared to the 4" driver. Also the cone material is uninspiring, appearing to be an untreated paper/nomex blend with a poly dustcap. The peak on the top end lends an aggressive, raspy coloration to the sound if not filtered. Still, great midrange clarity just short of the best hard cone drivers and the best in this roundup with the Alpines right on it's heels.
xmag: ~6mm
xsus: ~7.5mm
http://diymobileaudio.com/pics/peerless830883/ts.JPG
http://diymobileaudio.com/pics/peerless830883/klippel.JPG
http://diymobileaudio.com/pics/peerless830883/dist.JPG
Rainbow Platinum:
A gorgeous looking driver with an aluminum cone and polished chrome phaseplug. The motor is especially appealing to look at, although it's a bit of a guess as to what's inside. The driver gives the appearance of a rear vent, however there is none. There are also some small holes under the spider for venting. Not as open as I'd like to see but understandable for a driver designed for use in a car. No shorting ring as evidenced by the Le curve below, and the use of a tall cupped spider is somewhat of a rarity these days and a small surprise in a driver this expensive.
Looking at the Klippel analysis, the BL curve is excellent and by far the best in this roundoup. Textbook parabola shape, perfect centering and symmetry. Cms curve looks to have excellent centering, but with very poor symmetry. Le curve is unremarkable.
One thing to note is the Rainbow plat had exceptionally low mechanical noise. Better than even than Peerless Exclusive which is quite good already. Lowest xmax of the group however (not taking into consideration coil offset), and poor low end anechoic sensitivity. When used in a car door I could see the bass being a bit lean, but perhaps cleaner due to the early rolloff and the fact that most doors tend to have significant resonance issues in the 200hz region. I found the midrange clarity to be similar to the Seas L18RNX/P, which is to say very good, and close in performance to the Scans.
http://diymobileaudio.com/pics/plat7/ts.JPG
http://diymobileaudio.com/pics/plat7/klippel.JPG
http://diymobileaudio.com/pics/plat7/dist.JPG
Xmag: ~5.5mm
Xsus: >10mm
Alpine z18w:
Based on the Scan-Speak revelator, albeit with a remarkable markup. The worst Klippel performance in this group, although excellent Le curve. Bl curve is your textbook parabola, although severely offset in the forward direction and slightly assymetrical. Same with the Cms curve. Could possibly just be a poor sample, or not. Basket does not use the same "grasshopper" style as the Revelator, and is far more obstructive. Again, understandable for a car driver. Nice terminals though, and the only driver to feature a pole vent. Another interesting thing is the driver is coated on both sides, unlike the oem unit which is either untreated or treated only on the top side. I can't hear any audible difference, but then again I didn't have both drivers side by side to compare. Still the most unique, and advanced cone material of the bunch.
T/S parameters are much better suited to use in a car door, at the expense of overall driver efficiency. Clearly, the easiest driver of the bunch to throw in a door and get good results out of the box. Highest mechanical noise of the group by a large margin. For the money, I find it hard to recommend over the oem unit.
http://diymobileaudio.com/pics/alpinew18z/ts.JPG
http://diymobileaudio.com/pics/alpinew18z/klippel.JPG
http://diymobileaudio.com/pics/alpinew18z/dist.JPG
Xmag: ~5mm
Xsus: ~10mm