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JBL e140 cab

#3
I also find this, for a smaller box than a 4625b

jbl.jpg
 
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#4
That's part of the math, but knowing and understanding the results is how to insure the best possible performance. Since the E-140 has a very limited low frequency power handling, optimizing is pretty important imo.
 
#7
You'll be happy enough if you build the cab described in that JBL Enclosure Guide. 4 cu. ft., tuned to 40 Hz...I'm not sure how you'd improve on that.

Edit: Just for the record, the 4625 cab is also 4.0 cu. ft., tuned to 40 Hz.
 
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#8
I'm using an E series in a Fender Rumble cab that has 2- 3" ports on the front. Dimension wise, compared to the chart, mine is about 2" higher than the 23" on the chart and 2" shorter than the 16" on the chart. POssibly they wash each other out?
If so would I have to increase to a 4" port, like the chart calls for? Or A longer or shorter port for the 3" dimension?
Thanks for any insight
 
#12
Pbman said:
I just used an online calculator and it's coming up with 3.9 cf.

But my ports are 3" dia x 5"

Would you go shorter or longer to make the speaker feel like a 4" port? Or cut the 4 " hole?
Click to expand...
Shorted, and with the limited power handling you will probably be ok as is. It won't hurt for the tuning to be a little bit higher either.
 
#13
eddiemac said:
You'll get premium tone with the 4.0 cu.ft. box mentioned above,
Click to expand...
With such a big volume like 4.0 cu.ft. the (HPF alignment) may become quite narrow to a Tschebycheff alignment.
Are you really sure that an alignment like this was wanted? Especially if the OP want's to power the cab with a tube head?

eddiemac said:
I'm currently experimenting with a K140 into a 3.2 cu.ft. box tuned to 40Hz.
Click to expand...

To my taste 40Hz of tuning was way to low and, I woudn't suggest it for 3.2 cu.ft. of net volume.
 
#14
Pbman said:
I just used an online calculator and it's coming up with 3.9 cf.

But my ports are 3" dia x 5"

Would you go shorter or longer to make the speaker feel like a 4" port? Or cut the 4 " hole?
Click to expand...

Before you cut 4" holes (ideal), try shortening your 3" diameter vents to 2 3/4", which should give about 40 Hz tuning. (The minimum recommended diameter is 3.172" according to BASSBOX). Chuffing is the term used to describe unwanted sounds coming from ports that are too small, especially evident at high volume levels.
Now you say 3.4 cu ft, so two 3" ports, 3 3/4" long.
 
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#16
That's based on one set of parameters, every solution is a compromise and I agree with ThisBass that a higher tuning might be an improvement.

The port velocity is dependent on power, and since the E-140 is good for about 150 watts RMS at low frequencies (maybe 200 with an aggressive HPF), that information needs to be added in.
 
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#17
eddiemac said:
Before you cut 4" holes (ideal), try shortening your 3" diameter vents to 2 3/4", which should give about 40 Hz tuning. (The minimum recommended diameter is 3.172" according to BASSBOX). Chuffing is the term used to describe unwanted sounds coming from ports that are too small, especially evident at high volume levels.
Now you say 3.4 cu ft, so two 3" ports, 3 3/4" long.
Click to expand...

What is in there now are 2- 3" x 5" ports
The original port , i think is, 2 1/2" long and I still have them. I could re-glue them in.
 
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#18
agedhorse said:
That's based on one set of parameters, every solution is a compromise and I agree with ThisBass that a higher tuning might be an improvement.
Click to expand...

What I want to avoid is the driver exceeding excursion limits, "farting," destruction, etc. My tonal settings will vary, possibly leading to accentuated bass at times. I guess I can use my HPF to combat the dangers, but safety for the K140 when using a Sunn Sorado is one of my primary goals.
 

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