Jbl - 8340 + 2226 diy

Nice.

This is what I think of as 'ye generic HE 3 way', a good 15 and a 6.5-10" mid with a CD+WG. JBL drivers were a long standing fave (and add a stack of 18's below and you had my PA) but they now split the role with AE's in the same format for surrounds, and a JBL/B&C combo coming for the bedroom.

Do yourself a favour and get the xover up to 250-300Hz or so, plug the ports on the 8340 and enjoy.

neat...are you running subwoofers with this setup?

if run sealed, you might want to apply some boost to give you a -3db point of around 60hz, then cross them to some subs, doesn't really matter what type. the suggestion to run them up to 250-300hz is a good one...minimum of 175hz for sure.

while heresy around here, since you have so many of those drivers, you could use three of them in three ported enclosures (~6 cubic feet ea.) tuned to around 22hz for your subs. that would give you >120db from ~20hz up, which is a lot. and since you don't appear to need a ton of spl, you could probably get away with running the three off a 500 watt amp (3x16ohms in parallel is ~5.3 ohms).

I believe Jesse has the sub thing handled by running 4 Avalanche 18's in an IB.

roger.

SSwwweeettt!

Watch any movies yet with these? I bet this combo would be pretty potent.

Hhhheeeeellllllll yyyeeaahhhh!!!

"2 more pairs of 8340's for sale."

buy them.

the e-145 units in those subs are going to be worth more than gold soon.

e145 > 2226h.

just in case you want to question their potential, they were used in the '85 everest:

http://www.audioheritage.org/html/pr...bl/everest.htm

yes. my bad.

I am using JBL 8340's for my front L,C,R and just love the sound from them, but one of my horns has lost output. It still plays, but the sensitivity went way down, about 6 db. I checked all the usuall things first, even all the x-over components because I have never seen a driver go down so much in level without distortion from rubbing or cracks. But as it turns out, I swapped the horns and the problem followed the horn. So if anyone on here has an extra 8340 horn they would like to sell I am interested.

This driver does not look like mine. My driver is not threaded onto the horn, it has I think 3 screws around the flange into the magnet assembly with the v.c. / diaphram assy. sandwiche between the magnet and horn. From some of the info I found on the web, it seems this horn/driver assy used in early 8340 speaker was made by Pyle for JBL. I am striking out on a replacement so far.

I pulled the part number from the JBL service manual. If it's different, I'd suggest you contact JBL and give them your unit serial number and see what they say. They may have spares.

jammin jersey may one for much less than new.

edit: i see the link above has them for $80 new. i'd just go with that.

My system is currently on the budget side with just the 8340's for the mains and a single LFE + bass redirect 18" ported sub with a bridged 600 watt JBL 6260 amplifier. I am currently crossing out of the 8340's at 60 hz to the common sub. I have drawn up plans for a custom speaker cabinet / baffle wall to house all the LCR and sub components and also be a screen frame, but that is a future project. For now I need to get this HF horn issue figured out.

I have a JBL technical manual for the speakers that is dated April 04 and it does match my speakers perfectly. The horn is marked as part number 336812-001 3/4 inch voice coil horn assembly. Here is the PDF tech manual...

http://www.jblproservice.com/pdf/The...eries/8340.pdf

The JBL driver replacement recomendation still lists this as a "current model" and no recomended substitute, so I guess I can try ordering it from JBL and see what they will hit me for it. It is not marked, but on another web page it did say made by Pyle for JBL.

Thanks for trying to help, and keep an eye out if one does show up.

Just hunting for small horns with similar spec, I found this.

http://www.mcmelectronics.com/produc...m_term=53-1260

It is a little smaller, so I will need to make a mounting ring, it loses about 2 db of sensitivity, but gains a lot more power handling. I really wonder how it compares on distortion?? Going from a 0.75 inch aluminum dome to a 1.35 inch titanium dome should help. Magnet also goes from 15 to 20 OZ, but I know gauss in gap means a lot more than plain weight. The price is hard to beat, I can buy 1 to just beat it up and see how it sounds before I commit to 2 or 3. I could just use the new one for Center and use my remaining good pair on Left/Right. My center is playing through a cloth screen, so I already have a little different tamber which I correct with EQ.

Email JBL and ask, the CS is usually very good. Also email any of the authorised resellers, like the one I linked earlier with the JBL part number, and what it's out of.


It is extremely unlikely to work with the original passive xover. Just buy the JBL part as you can't randomly substitute other drivers into xovers not designed for them.

I have done a bit of hunting so far and since this particular version of the 8340 has been discontinued since about 2005 I may be out of luck on a new replacement. The 8340A with the plastic cabinet and screw on driver came out before 2001, and I think the wood cabinet version changed over to the newer driver in the same time frame before they stopped making it alltogether. If one does turn up, I will use it.

Until I can find one though, for $12 each, I think this one might get me in the ball park.

http://www.mcmelectronics.com/product/53-1270

I have been a cinema sound installer for many years, and I know the different driver specs, even though small in this case will result in a different slope and balance especially around the x-over frequency. If I was trying to match other speakers, it could be a problem, but since it is just my 3 single speakers, and I have Eq for each one, I do not think the issue will be a problem at all. Worst case, I might have to adjust the impeadance matching section of the x-over. And since I have the full schematic of the x-over, I should be able to work that out once I sweep the new driver. At this point I think I am going to try the new horns in left and right, keep the JBL one in center and see how they compare. This will also give me a good spare for the center channel.

I just did a frequency sweep on the left and right horns, the level out of them is over 6 db different at the same drive voltage, and the current is almost identical. It appears the magnet has just lost it's strength. Just sticking a hunk of metal on the back and pulling it off, it sure does feel a lot weaker. I have never had a speaker demagnatize on me before.

Looks like I caught a lucky break. I located a single new old stock 8340 horn. It is on it's way to me. According to JBL it is no longer going to be made, so I hope this one holds up.

In case your curious... I used a tone generator set to 2,000 hz, at about one volt out. Connecte the good horn from the left speaker and measure just over 93 db at a little over a foot away. I swapped to the bad horn and the level was 79 db, or 14 db less at the cross over frequency. OUCH!! As I went up in frequency, the level difference did shrink a little, but even up at 10,000 it was almost a 10 db difference. No Eq is going to make that driver useable. The Audessey DSX XT sure tried though, cranking every band above 3 K right to the top.

My new horn is in, and it sounds great.

Jesse...
Any idea what your friend wants for the 2 pair of old 8340's??

Sorry, i was stuck working a week straight..

$50 a pair is a steal, any idea of the age or condition of them? I might take a chance on them at that price just to have spare parts in the garage.

I know what you mean, noone with meak sound systems really understands what 100 db really sounds and feels like, especially when it is clean with no distortion or rattles. In some cases it just does not seem loud, until you turn it down again. I routinely find myself listening to music well over 95 db on this system. With 96 db / watt @ 1 meter, I am able to maintain about 105 db of clean music at my main seating position.