lfh
11-20-2011, 02:40 PM
Hi all,
it's been a while since my last period of frequent visits and posts -- good to see so many familiar names and that this place is cooking as usual with creativity, nice projects and fun!
Anyway, I need some expert help on K140:s. Actually I've never seen one IRL (only D:s and E:s), but I've studied some pics lately, and apparently it came with two different types of surrounds.
First, to check if I have the terminology right, here's a pic of a 2216/LE15B with what I think is called a "triple-roll" (or "accordion") surround, since (as best can be seen about 3 o'clock) there are three peaks in the cloth cross section between the cone edge and the frame rim :
http://www.clipx.co.jp/archives/woofer/LE15B/3.JPG
Is this understanding correct, to begin with?
Now here are two pics of supposedly NOS K140:s, both with what to my eyes appear to be the same fundamental kind of surround as above:
http://johnkvintageguitars.homestead.com/JBL15s/K140E140E130/JBL15s600/K140frontandrear-01.jpg
http://www.talkbass.com/forum/attachment.php?attachmentid=236934&d=1321807089
However, in various factory pics of the K140:s in the library, the surrounds look more like that of the E140 shown below, i.e. a common (large) dual-roll design:
http://johnkvintageguitars.homestead.com/JBLE140front-1.jpg
See e.g. the 1978 Pro Catalog:
http://www.lansingheritage.org/images/jbl/catalogs/1978-pro/page10.jpg
Hence my questions number two and three are:
Was the K140 made in two versions over time?
If so, which version surround was used in the C8RK140 kit (discontinued in the 80:s)?
(If the dual roll version depicted in the catalog is the only proper factory version, the two K:s above are either after all equipped with aftermarket kits or hybrid recones.)
My final question is about the possibility of putting together a K140 cone kit, since the C8RE140 is not equivalent in many aspects (lighter cone, shorter VC and more), and may not cut it for purists.
Looking at TS parameters, it looks like one could get close e.g. by using a 2225 cone and VC, spider from a 2205 or other driver in the group below, and an aluminum dome from a E140.
Mms = 105 // K140, 2205, 2225, 2234
Vas = 297 // K140, D130, K130, E130, E140, 2205, 2220
Xmax = 5.08 // K140, 2225, 2231, (2203)
Re = 5.5 // K140 only!
Le = 1.3 // K140 only!
What are your thoughts on this?
Finally, I'd say (not based on real world observations, though) that a K140 frame with a C8RE140 in essence sounds and behaves like an E140, at least much more so then a K140, since the E140 cone assembly would be the "sonically dominating factor" (by means of the TS parameters of course, but also less easily quantified aspects) rather than the slight difference between the AlNiCo and Ferrite engines. Would you agree (based on testing or theory)?
Optional question (bass players input especially welcomed): Which is your preferred driver (sound wise) of D140F, K140, and E140, and why?
TIA.
it's been a while since my last period of frequent visits and posts -- good to see so many familiar names and that this place is cooking as usual with creativity, nice projects and fun!
Anyway, I need some expert help on K140:s. Actually I've never seen one IRL (only D:s and E:s), but I've studied some pics lately, and apparently it came with two different types of surrounds.
First, to check if I have the terminology right, here's a pic of a 2216/LE15B with what I think is called a "triple-roll" (or "accordion") surround, since (as best can be seen about 3 o'clock) there are three peaks in the cloth cross section between the cone edge and the frame rim :
http://www.clipx.co.jp/archives/woofer/LE15B/3.JPG
Is this understanding correct, to begin with?
Now here are two pics of supposedly NOS K140:s, both with what to my eyes appear to be the same fundamental kind of surround as above:
http://johnkvintageguitars.homestead.com/JBL15s/K140E140E130/JBL15s600/K140frontandrear-01.jpg
http://www.talkbass.com/forum/attachment.php?attachmentid=236934&d=1321807089
However, in various factory pics of the K140:s in the library, the surrounds look more like that of the E140 shown below, i.e. a common (large) dual-roll design:
http://johnkvintageguitars.homestead.com/JBLE140front-1.jpg
See e.g. the 1978 Pro Catalog:
http://www.lansingheritage.org/images/jbl/catalogs/1978-pro/page10.jpg
Hence my questions number two and three are:
Was the K140 made in two versions over time?
If so, which version surround was used in the C8RK140 kit (discontinued in the 80:s)?
(If the dual roll version depicted in the catalog is the only proper factory version, the two K:s above are either after all equipped with aftermarket kits or hybrid recones.)
My final question is about the possibility of putting together a K140 cone kit, since the C8RE140 is not equivalent in many aspects (lighter cone, shorter VC and more), and may not cut it for purists.
Looking at TS parameters, it looks like one could get close e.g. by using a 2225 cone and VC, spider from a 2205 or other driver in the group below, and an aluminum dome from a E140.
Mms = 105 // K140, 2205, 2225, 2234
Vas = 297 // K140, D130, K130, E130, E140, 2205, 2220
Xmax = 5.08 // K140, 2225, 2231, (2203)
Re = 5.5 // K140 only!
Le = 1.3 // K140 only!
What are your thoughts on this?
Finally, I'd say (not based on real world observations, though) that a K140 frame with a C8RE140 in essence sounds and behaves like an E140, at least much more so then a K140, since the E140 cone assembly would be the "sonically dominating factor" (by means of the TS parameters of course, but also less easily quantified aspects) rather than the slight difference between the AlNiCo and Ferrite engines. Would you agree (based on testing or theory)?
Optional question (bass players input especially welcomed): Which is your preferred driver (sound wise) of D140F, K140, and E140, and why?
TIA.