RobB Posted January 31 Posted January 31 (edited) Got these today off Craigslist. These are the same as L100s, but with different grilles and crossover controls mounted on the front baffles. They are in great shape and sound great. Now I have to schlep my 80lb Cerwins to Goodwill. And what else does an erstwhile soundman use to ring out a system? Yep, you guessed it: Edited February 1 by RobB 16 Quote
Cboss Posted February 1 Posted February 1 Picture with the baffle off please! What year are they? 1 Quote
HSB0531 Posted February 1 Posted February 1 2 hours ago, Cboss said: Picture with the baffle off please! What year are they? https://www.audiosciencereview.com/forum/index.php?threads/jbl-4312m-ii-3-way-studio-monitor-review.51226/ 1 Quote
Hbom Posted February 1 Posted February 1 Nice catch. Congratulations. But sometimes I wish thread titles were spelled out. My dyslectic ass saw the title and opened the page expecting an invite to another coldest weekend in February jam in a certain well-known hang in the upper Midwest. Damn fine speakers though. Congrats again. Quote
topekatj Posted February 1 Posted February 1 Nice snag, the 12” bass driver in those is hard to beat. I’ve had a pair of 4311Bs forever, they now part of my lofi ‘video audio’ rig. The mid and high attenuators are notorious for failing. If they are not working properly I can offer input on how to access them for replacement. Have fun with those Quote
RobB Posted February 1 Author Posted February 1 (edited) 8 hours ago, Cboss said: Picture with the baffle off please! What year are they? They are mirror image arrays. Left: Right: As far as the year, I didn’t ask the guy. I’m thinking 80’s, due to the relatively primitive, push-button speaker terminals. I listened to about 10 lps/cds yesterday. Everything from Miles to Entombed. The mid/treble knobs work as they should, woofer surrounds are tight and right. They took some getting used to, as the bass response has a different curve than the Cerwin 217r pair. The Vegas are HUGE, with 15” woofers and big, deep cabinets. Alas, time has taken its toll, as the L-pads are shot. I was going to Craigslist them, but I can’t even get local repair techs to take them for spare parts. Off to Goodwill for a $300 donation tax deduction. They make great speaker stands for the JBLs, though. ETA: I met the Craigslist seller in a Starbucks parking lot in Livermore. He pulls up in an older Toyota minivan. Inside, he has a power strip, hooked up to a 12 V system. Plugged in were a Carver power amp, Neumark cd player and the speakers! I isolated each speaker and checked the crossovers. Cranked it up loud to listen to the woofers. It all checked out! Best eight bills I’ve spent in a long time. Edited February 1 by RobB 3 Quote
HSB0531 Posted February 2 Posted February 2 19 hours ago, topekatj said: Nice snag, the 12” bass driver in those is hard to beat. I’ve had a pair of 4311Bs forever, they now part of my lofi ‘video audio’ rig. The mid and high attenuators are notorious for failing. If they are not working properly I can offer input on how to access them for replacement. Have fun with those The good thing is that the components on the crossovers and the attenuators themselves can be swapped out with higher wattage units. Both the 4311 & L100 had woofers with nearly identical T/S specs, but all the speaker components in the L100 where alnico vs ceramic for the 4311. The 4311 woofer was rated at 75 watts vs the L100 at 50. The crossover frequencies were different also. The L100 speaker arrangement was vertically inline, ( better ) while the 4311B was staggered. The L100 speakers ( home consumer ) were brighter where the 4311B units were smoother ( pro recording studio ). The new JBL versions of each have completely new crossover networks and speakers. There's a huge following and demand for both the original L100 and the 4311B speakers. 4311B's were a long time studio reference speaker as well as the Altec Big Red 15" coaxial monitors, and U.R.E.I. 809/811/813/815 series of coaxial monitors. 1 1 Quote
topekatj Posted February 3 Posted February 3 Thanks for the info @HSB0531. Differences between the 11Bs and 12’s include: - the drivers in the 11Bs aren’t a mirrored set as shown in Rob’s photos - I believe the 11Bs were meant to be installed suspended such that the woofers were at the top of the enclosure and the attenuators were at the bottom. Since my speakers are now set up as shown in Rob’s photos (woofers at the bottom, attenuators at the top), the nameplate text is now upside down on my speakers. And the attenuator knobs are located on the (now) ‘top left’. 1 Quote
HSB0531 Posted February 3 Posted February 3 (edited) 4 hours ago, topekatj said: Thanks for the info @HSB0531. Differences between the 11Bs and 12’s include: - the drivers in the 11Bs aren’t a mirrored set as shown in Rob’s photos - I believe the 11Bs were meant to be installed suspended such that the woofers were at the top of the enclosure and the attenuators were at the bottom. Since my speakers are now set up as shown in Rob’s photos (woofers at the bottom, attenuators at the top), the nameplate text is now upside down on my speakers. And the attenuator knobs are located on the (now) ‘top left’. I believe that the whole 43xx series is supposed to be used in the nearfield monitor position ( 4310/11/11B/12 ). The 4311's as you mentioned, are not mirror image, and have the woofer on top with the port and midrange in the middle and tweeter on the bottom. They're designed to be vertically mounted. The 4312's are mirror image, vertically mounted. The woofer is on the bottom, the tweeter and midrange are in the middle, and the port is on top. The 4310's are the same layout as the 4311's, having the port and midrange on the sides and the tweeter on the bottom. Edited February 3 by HSB0531 1 Quote
topekatj Posted February 3 Posted February 3 (edited) @HSB0531 You got me curious when you described how the drivers and port are aligned in the various models. The drivers and ports in my 4311Bs are aligned just as Rob’s photos show above, but they’re not mirrored. A photo below shows the 4310 alignment, perhaps the 4311’s are similar Edited February 3 by topekatj Quote
Dave Scepter Posted February 3 Posted February 3 Hey Rob, did you get rid of those CV speakers? Quote
RobB Posted February 4 Author Posted February 4 22 hours ago, Dave Scepter said: Hey Rob, did you get rid of those CV speakers? Yep. Some lucky shopper is gonna get a smokin’ deal. 1 Quote
RobB Posted February 4 Author Posted February 4 (edited) Got my turntable serviced (resoldered RCA connectors, 33/45rpm strobe pots cleaned. Vintage hi-fi needs occasional maintenance, but it’s worth it. Edited February 4 by RobB 2 Quote
JGale Posted February 5 Posted February 5 (edited) Looky Here... https://reverb.com/item/86999756-near-mint-jbl-4312a-speakers-incredible-sound-1-year-warranty Edited February 5 by JGale 2 Quote
HSB0531 Posted February 5 Posted February 5 (edited) On 2/3/2025 at 11:29 AM, topekatj said: @HSB0531 You got me curious when you described how the drivers and port are aligned in the various models. The drivers and ports in my 4311Bs are aligned just as Rob’s photos show above, but they’re not mirrored. A photo below shows the 4310 alignment, perhaps the 4311’s are similar Correct. The 4311B's that you have are not mirror image. The 4312's were the model that were mirror image. When talking about the original 4310, 4311. and 4311B series of speakers those models were non-mirror image. Some other differences in the 4310, 4311 / 4311B were where they placed the port midrange and tweeter units around the woofer. The 4311 and 4311B had all components mounted to a single baffle with the port on the bottom. The 4310 had the port, mid and high frequency units mounted on a thin sub baffle that attached to the main baffle. This brought the port, mid/hi units level with the woofer frame with the port on the right and tweeter on the bottom. Edited February 5 by HSB0531 1 Quote
Dave Scepter Posted February 5 Posted February 5 (edited) On 2/2/2025 at 11:21 AM, HSB0531 said: The L100 speaker arrangement was vertically inline, ( better ) I have 2 pairs of L100's that are staggered not inline Edited February 5 by Dave Scepter 2 Quote
HSB0531 Posted February 5 Posted February 5 3 hours ago, JGale said: Looky Here... https://reverb.com/item/86999756-near-mint-jbl-4312a-speakers-incredible-sound-1-year-warranty 2 hours ago, Dave Scepter said: I have 2 pairs of L100's that are staggered not inline Yup, over the years they changed the layout on the baffle. The original L100's had all speaker components vertical inline with the 15" on the bottom. The L100A: staggered mids & highs. The L100 Century ( Ver. 1 ): were vertically aligned. The L100A Century ( Ver. 2 ): staggered mids & highs. The L100A Century ( Ver. 3 ) different drivers and grille hardware. 1 Quote
RobB Posted February 6 Author Posted February 6 10 hours ago, JGale said: Looky Here... https://reverb.com/item/86999756-near-mint-jbl-4312a-speakers-incredible-sound-1-year-warranty There’s some shenanigans going on with this pair. Nothing wrong with restored speakers, but the mid/tweets look like replacements. Buyer beware. Quote
Dave Scepter Posted February 6 Posted February 6 1 hour ago, RobB said: There’s some shenanigans going on with this pair. Nothing wrong with restored speakers, but the mid/tweets look like replacements. Buyer beware. I have a pair of L80t's that have those same Mids & Tweets Quote
RobB Posted February 6 Author Posted February 6 Well, I’ve been wrong before. They look like drivers from much later versions than the 70s models. Quote
HSB0531 Posted February 7 Posted February 7 (edited) On 2/5/2025 at 10:23 PM, RobB said: There’s some shenanigans going on with this pair. Nothing wrong with restored speakers, but the mid/tweets look like replacements. Buyer beware. The 2213H, 104H, and 035Ti are JBL raw frame speakers found in the 1980's and 90's era JBL studio monitors. They are the components for the 4312A. Edited February 7 by HSB0531 Quote
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