jbl 2426/7 compression driver, hiss and frekvency range

Hi all,

i have a hiss from my jbl 276nd tweeter, (almost 100% identical to the 2426/7).

the hiss is not a 60hz hum. the hiss is there with nothing but the poweramp connected, with signal cables disconnected.

do you have the hiss also, and can you hear it from 2meter/6,5(my listening distance) feet away?

i presume the hiss is there because of the drivers high sensitivity and the hornloading?

is there anything i can do about it?

how high will the 2426/7 do? can i eq it to cover all the way up to 16-20khz?


best regards


panduro, newbee in jbl and hornloading

Quote:

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Originally Posted by panduro

Hi all,

i have a hiss from my jbl 276nd tweeter, (almost 100% identical to the 2426/7).

the hiss is not a 60hz hum. the hiss is there with nothing but the poweramp connected, with signal cables disconnected.

do you have the hiss also, and can you hear it from 2meter/6,5(my listening distance) feet away?

i presume the hiss is there because of the drivers high sensitivity and the hornloading?

is there anything i can do about it?

how high will the 2426/7 do? can i eq it to cover all the way up to 16-20khz?


best regards


panduro, newbee in jbl and hornloading

---

The hiss is coming from your amplifier, you hear it more than with a standard dome tweeter because of the increased sensitivity of the driver/horn combination.

What kind of amp are you running? Are you using an amplifier only for those (bi/tri-amp) or the 2426 are part of a ful range system?

Did you setup your gain structure properly?

hi eaulive,
thanks for your answer.

building a 5.0 surround set.

fronts consist of
jbl 276nd(2426)
jbl 726gs 6,5" midrange
jbl 120h-s1 12" bass

dbx driverack plus filters/xovers


10year old carver thx 5 x 125w

i dont know what that means, so no i havent:(

how is that possible on a poweramp?

best regards

panduro

Quote:

---

Originally Posted by panduro

hi eaulive,
thanks for your answer.

building a 5.0 surround set.

fronts consist of
jbl 276nd(2426)
jbl 726gs 6,5" midrange
jbl 120h-s1 12" bass

dbx driverack plus filters/xovers


10year old carver thx 5 x 125w

i dont know what that means, so no i havent:(

how is that possible on a poweramp?

best regards

panduro

---

I don't know consumer models too much.
Do you have a gain control on the amplifier? If you have, turn it down completely and see if the hiss remains.
You say the hiss is present even with the input cables disconnected?

This is from the Rane Web Site;

http://www.rane.com/note135.html

It explains it but may be tough reading if you aren't to savvy with Pro Gear.

Basically you are amplifying the back ground noise. The amp gain needs to be dialed back a bit and only turned up enough to keep up with the other drivers.

I run my 2445's with a Hafler P3000 amp and set the amp's gain to -15 (max cut). Almost all the hiss is gone like that and the system can still hurt your ears bad!:crying: This is in my living room.

thanks everybody,

no it doesnt have gain control, but havent bought all the nessecary amplifiers as i all in all will need 14 and only got 10channels. what amp would be good for the tweets?

just printet that link, gonna read and get back later.

how high up in the frequency range can i make the 2426 go with eq?

best regards

panduro

Quote:

---

Originally Posted by panduro

thanks everybody,

no it doesnt have gain control, but havent bought all the nessecary amplifiers as i all in all will need 14 and only got 10channels. what amp would be good for the tweets?

just printet that link, gonna read and get back later.

how high up in the frequency range can i make the 2426 go with eq?

best regards

panduro

---

I use Crown D-60, D-45 and BGW-Model 75 for tweets, with no discernible hiss at the proper listening distance.

Having level controls on your amps allows you to get the gain of the pre-amp and XO right for those components, then set the level you want in the room.

thanks again everybody,

ill see if i can borrow a poweramp with gaincontrol, to see if my problem vanishes or reduces.

best regards

panduro