JBL 4301B / L36 Stack - 125a driver re-foam question

[ahartig]

Have the opportunity to pick up a good looking pair of freshly refoamed JBL 4301Bs. Am thinking about stacking them with a pair of L36 that I recently picked up. Any thoughts?

They would be powered by a Sansui 9090db, Marantz 2245, or Pioneer SA-7800.

Was thinking I could lay the L36 on their side and stack the 4301B on top. L36 would add to midrange and bass.

Sensitivity wise its not apples to apples as the specs I have found from JBL pamphlets indicate the 4301B is as follows:

- 88 dB SPL measured at 3.3 ft with a 1-watt input

L36 is as follows:

- 76 dB SPL measured at 15 ft with a 1-watt input

Using above, I plugged the info into this "Inverse Sqaure Law" web page to estimate 4301B dB level at 15 ft..... it spit out a dB reading of 74 at 15 feet......

http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/isprob2.html

Am i missing something, sensitivity wise they would seem to be good match.

 

[rollcentre]

Well, i'm not entirely sure about stacking them as I've never personally stacked the two, They will have pretty similar voicing so it could work.

What I can tell you is the 4301B is an excellent speaker by itself. I find that they have an impressive bottom end that isn't overly boomy. Don't judge a book by its cover with these! They sound bigger than my 4312B's. If you like the paper cone tweeter monitor sound, it doesn't get much better.

 

[mech986]

Did you ever get the 4301B's?

 

[GD70]

4301b's are shockingly good for their size. Also somewhat collectable as they are fairly rare.
I think stacked could sound good, but only your ears can determine this. Connecting them in series as opposed to parallel will not put as low an ohm load on your amp or receiver.
So yes, did you get them?

 

[ahartig]

Did you ever get the 4301B's?

4301b's are shockingly good for their size. Also somewhat collectable as they are fairly rare.
I think stacked could sound good, but only your ears can determine this. Connecting them in series as opposed to parallel will not put as low an ohm load on your amp or receiver.
So yes, did you get them?

Yes, got these as well as sweet Rega Elicit MK1 amp that I couldn't pass up .

Apparently the seller had just had the woofer and tweeter re-foamed..... never heard of a tweeter needing a re-foam job, but he went to an authorized JBL dealer in the valley to do it. No grills though. Anyone know where I could find a decent pair of grills without paying an arm and a leg on eBay?

I have not had time to perform the re-foam job on my newly acquired 125a woofers for the L36, but when I do I will stack away. I ordered the foam from looneytunes on eBay and it seems to be very thin..... compared to some Mach 2 foam i ordered. I assume this is due to the Mach 2 having a 15" woofer and the Jbl being 8"....

I could power the stack with a newer Marantz 8500 receiver seen in the pics and turn on both A and B speakers (same with the Pioneer SA-7800 seen in pics as well), or I could hook them up in series to the Rega... Or in parallel. The Rega is rated down to 4 ohms..... would parallel possibly be too taxing on the Rega? Rega specs posted below

 

[mech986]

Hmm, look pretty nice. However, normally the original 4301 with black baffle has the JBL 116A alnico magnet woofer and the LE25-2 tweeter with thick neoprene foam damping circle. The later 4301B has the revised ferrite motor 116H woofer and the LE26 tweeter which is the same general LE25 tweeter with a plastic sloping mounting plate. It could be the PO had to replace the tweeter at some point and used an older pair of LE25 like in the JBL L100/4311 or the LE25-2 .
Only way to tell is pull the drivers and check model numbers. The 4301s and similar L19's respond well to recapping the crossovers with better film caps if you're interested.

 

[superdog]

Due to space issues I have had to stack.Try stacking on their sides with both woofers in board.Just a suggestion.

 

[ahartig]

Due to space issues I have had to stack.Try stacking on their sides with both woofers in board.Just a suggestion.

Stack woofers on top of each other?

I'll have to check on the tweeter status.

 

[superdog]

y

Stack woofers on top of each other?

I'll have to check on the tweeter status.

Yes.

 

[ahartig]

Semi on topic question related to the L36 set I have. Was able to pick up the L36s for $80 off clist about a month ago. Owner had inexplicably replaced the 125A woofers with realistic ones back in the day.... needless to say, first order of business was to find a decent set of 125As and get them back in their home. I got a pair off ebay for $80 that needed refoam. Did the refoam job last night and they came out great but t is was close to impossible to get the old surround from under the cone off. I tried my best with the rubbing fingertip method, but anything more intense and I was worried i'd damage the cone or worse the voice coil.

Anyways just making sure that its not a big deal if the remnant of the old surround was left under the cone. I rubbed off all the bits that were able to come off. Here are some pics to illustrate.

The final pic shows close up of the final product.

 

[bolero]

FWIW I am stacking

JBL 4313
JBL L26

and they sound great together. speakers are sideways with the tweeters on the outside. Sansui AU 7700 amp

 

[mech986]

Ahartig, as long as the foam part was removed well, the old adhesive left there is fine, even if it formed a bit of a lip at the cone edge. The refoam looks very nice. If you used a good typical reforming glue and spread it evenly, it will adhere to the old adhesive and new surround. Nice job in reusing the OEM JBL Neoprene front gaskets for that original look!

A tip for future refoams, a 1/2"-1" wide sharp wood chisel used carefully will scrape away the old foam easily, and in some cases can also get the old adhesive off if desired IF one works carefully and with a few passes at the cone. I've also used a plastic or metal putty knife or spreader but I find a sharp chisel works better - just take your time and keep the angle shallow to avoid gouging the paper cone. The chisel works really well for the wide flat frame mounting surface for the OD of the surround - can get that area really clean of old adhesive and flat if desired without resorting to any harsh solvents.

Another small detail is to use a 1-2" wide rough metal file on the front frame lip of JBL frames to brighten them up - be sure though to round off the inner and out frame lip edges afterwards as they can have some sharp burrs that are sure to catch your finger. Really gives that nice finished look and many times visible even under the grille cloth. Some have even polished the frame edge which also stands out given the thick edge of the JBL cast aluminum frame.

 

[ahartig]

A tip for future refoams, a 1/2"-1" wide sharp wood chisel used carefully will scrape away the old foam easily, and in some cases can also get the old adhesive off if desired IF one works carefully and with a few passes at the cone. I've also used a plastic or metal putty knife or spreader but I find a sharp chisel works better - just take your time and keep the angle shallow to avoid gouging the paper cone. The chisel works really well for the wide flat frame mounting surface for the OD of the surround - can get that area really clean of old adhesive and flat if desired without resorting to any harsh solvents.

Another small detail is to use a 1-2" wide rough metal file on the front frame lip of JBL frames to brighten them up - be sure though to round off the inner and out frame lip edges afterwards as they can have some sharp burrs that are sure to catch your finger. Really gives that nice finished look and many times visible even under the grille cloth. Some have even polished the frame edge which also stands out given the thick edge of the JBL cast aluminum frame.

Thanks for the feedback, I definitely need to invest in some better tools. Getting the old glue off was a pain as I was using a flathead screwdriver and relatively rigid putty knife..... It was a good workout...lol. Scraper is a must.

That remnant foam underneath the cone was on their tight. I don't see how a chisel would remove it without damaging the cone to some extent. Ill have to try very carefully next time.

Finally was able to listen to the L36 as they were intended last night and was comparing to a set of RSL 3600 monitors. The JBLs were much crisper and separation of instruments was more prominent. I could see the L36 being a tad more fatiguing then the 3600s though. Overall very different sounding but each unique and enjoyable. The L36 seemed to shine more with rock music. The 3600s will stay in the garage workshops and I plan on stacking the L36 and 4301Bs today in the office. I wont use the Rega to power as i think it would be too stressful, the unit gets pretty hot just powering one set of speakers. Trying to decide whether to use a Marantz 8500 a/v receiver or a Pioner sa 7800, both have A and B speaker outputs.

 

[mech986]

Many JBL speakers with the LE5 midrange and LE25 type paper cone tweeter will sound a bit forward and hot although the tweeter actually rolls off above 15khz. This is because they have a somewhat peaky response. Many prefer the sound with the presence and brilliance controls dialed down quite a bit, and a few have resorted to the old AR / Advent tissue paper filter over tweeter tweak. OTOH, you might also consider recapping the crossover with smoother polypropylene caps that are not known to be bright ( e.g. don't use Solens or Daytons) or consider a crossover mod similar to the JBL L100 Murphy or Troels Gravesen mod. The Murphy mod is well known and the L100 mid and tweeter are very similar to the L36 components.

 

[ahartig]

Stacks loaded. Had to stack vertically due to space constraints, ill try to fix to horizontal later this week. Is this the best config for vertical stack? Or should i invert so tweeters/mids are in middle?

Other random questions, currently streaming off Tidal HiFi setting with a fiio DAC. What should be the default volume out from my computer and Tidal player?

Currently I have my system volume at 50%, receiver relatively high, and adjust listening volume via tidal in chrome browser. Any right or wrong way to do this?

 

[Zonker92]

Pretty cool. So you have a choice between analog attenuation (receiver volume control) and digital (Tidal). Depending upon how it's done, one of them may be better than the other, but I don't know enough about the Tidal to say. You might compare them to see which you like better in terms of sound quality, signal to noise, channel balance, etc. It probably depends a lot upon the DAC in your PC.

More here:

http://www.soundstageultra.com/inde...311-what-s-wrong-with-digital-volume-controls

You might also consider bypassing the receiver's preamp section, if it has separate amplifier input jacks, and using Tidal as your volume control. And if appropriate, you might want to shop for a nice PC sound card; there are tons of them out there, including used ones on eBay.

 

[ahartig]

Pretty cool. So you have a choice between analog attenuation (receiver volume control) and digital (Tidal). Depending upon how it's done, one of them may be better than the other, but I don't know enough about the Tidal to say. You might compare them to see which you like better in terms of sound quality, signal to noise, channel balance, etc. It probably depends a lot upon the DAC in your PC.

More here:

http://www.soundstageultra.com/inde...311-what-s-wrong-with-digital-volume-controls

You might also consider bypassing the receiver's preamp section, if it has separate amplifier input jacks, and using Tidal as your volume control. And if appropriate, you might want to shop for a nice PC sound card; there are tons of them out there, including used ones on eBay.

I'm using USB out from pc and connected directly to a Fiio Q1 Dac. The Fiio is straight line in to line out, no volume control. I have the two digital controls on the PC though, system volume and Tidal volume. Then analog at the receiver.

 

[Zonker92]

OK; I'm out of my depth on that issue. Maybe someone here will chime in, or you could start a new thread in the digital section.

 

[ahartig]

Wow. So after a few hours of listening I can confirm the L36/4301b stack is not my cup of tea. Having them both play at the same time seemed to double down on the brightness/hotness, made it almost a chore to listen to. Each individual set of speakers playing on their own, sound great. I may play around with stacking horizontally, but I doubt that will help.

 

[ZOOM]

Stacking speakers can never sound good, and works against each speaker. It's a teenager thing to do, more noise and less hifi. It's not very clever.