PDA

View Full Version : Less mid range output on JBL control 1



JBL 4645
09-19-2007, 03:19 AM
Iíve noticed that one of the or two of JBL control 1 seams to be a little less in the midrange output the high frequency end seams okay, I was wondering it could be something to do with the passive crossover network?

Is it possible that thereís a faulty passive crossover to reduce mid range output? And if so can the situation be corrected with minimal fuss with a little soldering technique.

Thanks.:)

Guido
09-19-2007, 03:52 AM
Check the polarity. That is a common fault.

JBL 4645
09-19-2007, 04:38 AM
Check the polarity. That is a common fault.


Guido

Hmm you mean common as to reduce the midrange output via the passive crossover, are you sure about this, I mean that does sound very odd.

No, matter I’ll run a thorough check of the passive crossover when I get back from the shops, I still find it odd though that it would be the passive crossover. What I’ll do is disconnect the bass mid terminals and power it directly with low level pink noise I’ll test a few out to determine whether it’s in fact a passive crossover fault or other.

Thanks.:)

hjames
09-19-2007, 06:36 AM
Have you opened the speaker and changed any of the wiring internal to the driver? If you have not done that for a while its probably not internal to the speaker then. Unless your components have failed.



Guido

Hmm you mean common as to reduce the midrange output via the passive crossover, are you sure about this, I mean that does sound very odd.

No, matter I’ll run a thorough check of the passive crossover when I get back from the shops, I still find it odd though that it would be the passive crossover. What I’ll do is disconnect the bass mid terminals and power it directly with low level pink noise I’ll test a few out to determine whether it’s in fact a passive crossover fault or other.

Thanks.:)

JBL 4645
09-19-2007, 07:31 AM
Have you opened the speaker and changed any of the wiring internal to the driver? If you have not done that for a while its probably not internal to the speaker then. Unless your components have failed.

Hi there Heather

Well that’s what I find unusual I opened two of up yesterday to see if the wiring was accidentally reversed. But all that would do is create a less bass output when two loudspeakers are playing the same bass signal.

No this I think is something other the ole JBL control 1 will produce bass it just sounds less in the mid range output around -3 to 4 db.

Anyway I’ve just got back from Winton high street so I’m going to relax for a few hours then take another look at the situation. If two JBL control 1 play without the internal passive crossover connected and each output a reassemble SPL that should be equal then it’s down to the passive crossover.

If the JBL control 1 that is playing slightly less than the others in its midrange output via testing it directly to the bass mid driver then it would be the fault of the bass mid driver.

duaneage
09-27-2007, 07:41 PM
Check the fuse inside the control 1, if it blows the output is reduced. The fuse seems to short a resistor and when it blows the resistor lowers the output to the driver. Unusual crossover feature it is.

JBL 4645
09-28-2007, 04:33 AM
duaneage

Thank you Iíll check the fuse with a volt metre again than thank you for bring that to my attention. :)

JBL 4645
09-28-2007, 05:42 AM
I checked the fuse by eye and with the volt metre and it checked out okay. I then tested the two JBL control 1 connected directly to the speaker cable terminal and there was a, -1db reduction and yes -1db does bother me its all about principles.

So we can rule out the crossover for starts.

How can someone fail to notice this before leaving the factory?

So you ask me what could it be, could it have something to do with the voice coil on brand new product?

http://i232.photobucket.com/albums/ee18/DemolitionMan3417/JBLcontrol1test1.jpg

http://i232.photobucket.com/albums/ee18/DemolitionMan3417/JBLcontrol1test12.jpg

http://i232.photobucket.com/albums/ee18/DemolitionMan3417/JBLcontrol1test13.jpg

http://i232.photobucket.com/albums/ee18/DemolitionMan3417/JBLcontrol1test14.jpg

mwaldron
09-28-2007, 08:27 AM
Did you see that boxes of six of these are offered in the tent sales? Looks like a good price for 6 pcs.

JBL 4645
09-28-2007, 08:51 AM
Did you see that boxes of six of these are offered in the tent sales? Looks like a good price for 6 pcs.

The what? I can buy these models or the black JBL Control 1 for little as much as £35.10p at (Future Projections) here in the UK.:D

http://www.fproj.com/fp_sound/speakers.html (http://www.fproj.com/fp_sound/speakers.html)

hjames
09-28-2007, 08:56 AM
The what? I can buy these models or the black JBL Control 1 for little as much as £35.10p at (Future Projections) here in the UK.:D

http://www.fproj.com/fp_sound/speakers.html (http://www.fproj.com/fp_sound/speakers.html)

the JBL Tent Sale, my good man ...

http://www.jblpro.com/commerce/tent_sale/catalog/index.php?cPath=23&sort=3a&page=2&osCsid=affd02707dbd2e6bedc77919e0bb8d33

Midway down the page - Quan 6 White Control 1s for $210 US - lets see - thats about $35 each

(or go here and click the Closeouts link, probably on pg 2
http://www.jblpro.com/commerce/tent_sale/catalog/)

Sorry, big whoops ...

We Cannot Ship Outside of the USA At This Time

mwaldron
09-28-2007, 08:59 AM
CONTROL 1-WH (6pcs)
[Control 1-WH]$210.00http://www.jblpro.com/commerce/tent_sale/catalog/images/pixel_trans.gifhttp://www.jblpro.com/commerce/tent_sale/catalog/images/Control%201%20wh.jpg (javascript:popupWindow('http://www.jblpro.com/commerce/tent_sale/catalog/popup_image.php?pID=229&osCsid=affd02707dbd2e6bedc77919e0bb8d33'))

JBL 4645
09-28-2007, 09:51 AM
http://www.jblpro.com/commerce/tent_...c77919e0bb8d33

That site is a bit steep for prices isnít :blink:! try looking for a JBL product under (Google Products) youíll find the best lowest prices going believe me.

Audiobeer
09-28-2007, 08:32 PM
At $35 bucks a pop they become darn near like disposable diapers. Use them and throw them away.

JBL 4645
09-29-2007, 01:36 PM
At $35 bucks a pop they become darn near like disposable diapers. Use them and throw them away.

LOL well there not bad diapers at least they come with a free mounting bracket. :D

pelly3s
10-01-2007, 05:23 AM
out of the probably 100 or so control 1's i have fixed i have noticed that problem can either be a bad crossover (possible short in a coil) or the VC in the driver has been heated and lowers the impedance of the woofer.