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JBL-K140
- Thread starter haujobb
- Start date
I sent the link to the JBL dungeonmaster, he will probably come up for air this weekend. His breath is a bit strong
though, like his opinions, so Ima gonna leave the room.
though, like his opinions, so Ima gonna leave the room.
billfitzmaurice
Commercial User
- Sep 15, 2004
- 16,860
- 278
- 76
- Disclosures
- Owner, Bill Fitzmaurice Loudspeaker Design
I never found them to be competitive with the Altec and EV drivers of that period. Figure 75 watts.
billfitzmaurice
Commercial User
- Sep 15, 2004
- 16,860
- 278
- 76
- Disclosures
- Owner, Bill Fitzmaurice Loudspeaker Design
billfitzmaurice
Commercial User
- Sep 15, 2004
- 16,860
- 278
- 76
- Disclosures
- Owner, Bill Fitzmaurice Loudspeaker Design
Tuned for flat response they like 1.2 cu ft each, but the f3 is only 80 Hz. 2 cu ft apiece is the minimum for decent bass, and 4 cu ft much better. This isn't a peculiarity of the K140. Many commercial cabs put too many drivers into too small a box, gaining power handling but sacrificing extension. A single Beta 10 will work to an f3 of 38Hz, but needs 5.5 cu ft to do it. That would make an 8x10 about 7 feet high, 3 feet wide and two feet deep for best results.
Thor said:I sent the link to the JBL dungeonmaster, he will probably come up for air this weekend. His breath is a bit strong
though, like his opinions, so Ima gonna leave the room.
I must be the Dungeonmaster to whom Thor was referring...
Measure the inside dimensions of your Traynor cabinet and tell me the size and amount of the ports and I'll run those measurements through my software and tell you what is what.
As for top end, the K-140s have pretty decent top end and it is helped out by the aluminum centerdome.
If I remember correctly ....well maybe not, the last Traynor 2x15 I saw was 30 years ago.
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until.tomorrow said:
Holy Smokes
That is the cabinet I remember!!!.I believe it is sealed unit so the porting is a moot point.
If you can pick it up in Maryland then the current price is a steal...
even if it gets to $300.00 it is still a steal because you are not usually gonna find K-140's for $150.00 each unless you are real lucky.
Besides, we can put in the ports to make it efficient any time.
Try to get the seller to measure the inside and I'll watch for your post, run the math real quick and then we will know.
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I checked with the Traynor Web-site and the YT-15 was sold as the YTL-15 when JBL 130's or 140's were installed by the factory.
So there is history for the cabinet as it stands.
I have a Word Doc with all the info I found that I can send.
Just PM me with you email address and I'll get it right out to you.
Dave
So there is history for the cabinet as it stands.
I have a Word Doc with all the info I found that I can send.
Just PM me with you email address and I'll get it right out to you.
Dave
haujobb said:
150 watts RMS each...300 watts for the box.
I push mine harder than that with an SWR 550x.
billfitzmaurice
Commercial User
- Sep 15, 2004
- 16,860
- 278
- 76
- Disclosures
- Owner, Bill Fitzmaurice Loudspeaker Design
If it is a sealed box even 8 cu ft would give an f3 of 130 Hz or so. I'd pop a ducted port in that puppy before ever plugging it in.
The K140-8 has an EBP of 136... putting this driver into a sealed box is a total mismatch, IMO. Like most JBL, this is a high efficiency driver designed for a vented enclosure.
This driver is optimally enclosed in 1.2 to 2 cubic feet. F3 is high, 72 ~ 95 Hz, which is typical of efficient JBL drivers. Power handling is 150w RMS, and unlike most Eminence drivers, the JBL will go full power without exceeding Xmax. You can expect 116 SPL maximum from this driver at 150w. This is only -3dB from the best that Eminence can offer, before they exceed Xmax and begin to distort.
You can extend the bass response somewhat by putting this driver into an EBS3 or EBS6 alignment. These are 4.25 cubic feet at 41 Hz, and 6.0 cubic feet at 30 Hz, respectively. The JBL construction documents reveal JBL favors the EBS alignment for their musical instrument drivers. These extend bass response by reducing the mid-bass. Group delay (mud) peaks sharply at the tuning frequency.
There is a radical difference between SBB4 and EBS3 alignments. Bill Fitzmaurice's measurements show that his bass produces little fundamental compared to the higher harmonics. If your bass performs the same way, having a big bottom at the expense of reduced mid-bass is pointless. If you play with a sub-synth (I do) or otherwise generate strong fundamentals from 31 to 64 Hz, a big bottom cab will be necessary.
This driver is optimally enclosed in 1.2 to 2 cubic feet. F3 is high, 72 ~ 95 Hz, which is typical of efficient JBL drivers. Power handling is 150w RMS, and unlike most Eminence drivers, the JBL will go full power without exceeding Xmax. You can expect 116 SPL maximum from this driver at 150w. This is only -3dB from the best that Eminence can offer, before they exceed Xmax and begin to distort.
You can extend the bass response somewhat by putting this driver into an EBS3 or EBS6 alignment. These are 4.25 cubic feet at 41 Hz, and 6.0 cubic feet at 30 Hz, respectively. The JBL construction documents reveal JBL favors the EBS alignment for their musical instrument drivers. These extend bass response by reducing the mid-bass. Group delay (mud) peaks sharply at the tuning frequency.
There is a radical difference between SBB4 and EBS3 alignments. Bill Fitzmaurice's measurements show that his bass produces little fundamental compared to the higher harmonics. If your bass performs the same way, having a big bottom at the expense of reduced mid-bass is pointless. If you play with a sub-synth (I do) or otherwise generate strong fundamentals from 31 to 64 Hz, a big bottom cab will be necessary.
