PDA

View Full Version : whats with watts



150a/250ti
01-30-2005, 06:05 PM
just a general question about tweeter watt ratings. i have decided i need to rebuild or replace my o44ti's in my 250 ti's. knowing this is going to be tough to find i started looking at other tweeters.now i notice some very expensive and massive tweeters have what seems like rediculously low watt ratings. (parts express) jbl 2402h 4 1/8 lbs magnet 258.90 each power rating only 40watts, ultra high frequency but it range is only up to 15000.does the crossover reduce the watts to the tweeter or should i be looking for a 400 watt tweeter to match the rating on my 250ti's

now a more specific question. where can i find the specs for the 044ti so i can find some other tweeter that can closely match its specs, i think its freq range goes up to 27000 and i dont know its sensitivity db 1/w 1/m. i guess i don't want the new tweeters to sound louder than they should. or can i lower that by loweriing the high freq bus bar in the back.

about ohms. i notice a lot of 8 ohm speakers measure out at less than 8 ohms usualy 5.7 or there abouts. can i stick a 6 ohm tweeter in the 250ti's or will i burn the house down.i'm asking these questions because my plan is to buy some cheap but new tweeters then take my time and find new diaphragms for the 044ti's. for now i have my L150A's right next to the 250ti's so their 044's are puting out enough highs that you wouldn't notice one of the 250's usualy has no highs and the other ones tweeter sounds weaker than the L150A's.on the 044ti's both tweeters have their domes dimpled so i guess thatdoes affect the sound. i guess someone should tell that to ebay

also where can i get an owners manual for the 250ti. the guy i bought the manual for my L150A seems to have L250 but not 250ti and in the HERITAGE library i only fond a 3 page very generic manual on the ti series. but i did find the exact copy as i bought for the L150a.

thanks for any help
jack

4313B
01-30-2005, 06:13 PM
Buy the 044Ti-1's from JBL. They have some left. They also have the diaphragm kits to fix yours.

As for a 2402H only handling 40 watts, read the pdf
40 watts continuous program power handling
110 dB sensitivity, 1 W @ 1 m (3.3 ft)
http://www.jblpro.com/pages/pub/components/2402.pdf

"For a given power input, the 2402H produces an exceptionally high acoustic output, converting a 10 W input into a sound pressure level of 100 dB at a distance of 10 m (33 ft). Such efficiency allows the 2402H to re-create intense high frequency onsets and transients with outstanding clarity and accuracy."

Here's something I just ripped off the net real quick -
"As a general 'rule of thumb', in the average music mix, the frequencies below 500 Hz use approximately 70% of the power. The frequencies above 500 Hz use the remaining 30 % of the power. The signals above 4000 Hz use approximately 15% of the power."

__________________
whenever i see a turtle crossing the road i always stop, get out of my car and tip it over onto it's back.

150a/250ti
01-30-2005, 06:52 PM
Thanks for the info giskard. I thought they were nla i'll check on diaphraghms tomorrow. I thought i was going to have to track down some after market crap diaphragms.about the 110 db sensisitivity on the 2402h thats why i wondered what the specs were on the 044ti I asumed it was around 89 to 91 which I thought my 250ti speakers probably were at. jbl speakers seem to have lower sensitivity than say cerwin vegas. my litlle L7's cerwin vegas are louder at 100watts than my L 150A's but tinier sounding.their sensitivity is 103 I think. I usualy play my stereo at 100 to 150 watts continuis peaking off the scale if i like the song. we have a large yard and my stereo is in a room behind the garage which itself is a seperate building from the house so i can crank it pretty loud.

4313B
01-30-2005, 06:57 PM
No, perhaps you're thinking of the 044. The silver diaphragm (L96/L112/L150A) is NLA but the gold diaphragm (L250) is still available.

__________________
whenever i see a turtle crossing the road i always stop, get out of my car and tip it over onto it's back.

150a/250ti
01-30-2005, 07:30 PM
I have caught Giskard in my yard, can you tell which one is him?

4313B
01-30-2005, 07:36 PM
:rotfl:

Cool pictures!

Turtle!

http://www.carstereoone.com/ - click on the media button in the broadband section and see how much Toledo likes Steve :banghead: Watch the guy between the two girls. :p

150a/250ti
01-30-2005, 08:04 PM
was that you. you sure looked diferent in my back yard tipping over that turtle.the set up kind of reminded me of the old memerex add only backwards with seatbelts.

4313B
01-30-2005, 08:11 PM
was that you.No :p
Here in Toledo we just hear "Turtle!" about twenty times a day.

John
01-30-2005, 11:16 PM
I Bumped into a turtle in Tomah Wi. after a thunderstorm in the summertime last year at 2.00 in the morning at a Wallmart Supercenter. He was in the middle of the parking lot and I thought hey I should direct him to the pond that i believed he came out of before he gets killed by a wallmart customer in a hurry to buy some cheap asian product. Wrong that turtle just about ripped my hand offhttp://audioheritage.csdco.com/vbulletin/images/smilies/banghead.gif

I must of been exposed to to much Disney when i was younghttp://audioheritage.csdco.com/vbulletin/images/smilies/baby.gif

hector.murray
01-31-2005, 06:03 AM
With regard to Ohms ratings on speakers, this is the impedance value, not strict resistance values. Without going into the mathmatical formulas for impedance calculation, suffice it to say that Impedance takes into account the inductance, capacitance and frequency of the speaker in question. When we look at the DC resistance of a voicecoil, it is a quick check of the speakers health. so, if a given speaker is listed as having an acceptable DC resistance of 4.0 to 6.0 Ohms and we put an Ohm meter across the voicecoil and see a 2 Ohm reading, then that would indicate that the voicecoil windings are shorting to themselves. Conversly, if we Ohm out a voicecoil and the resistance is infinity, then we know the voicecoil is open, or non continous. Either of the above cases are not good and require serious attention.
With regard to Watts, your 044ti tweeter does not handle 400 watts. The entire 250ti speaker handles 400 wats maybe, but the tweeter itself is rated somewhere in the 15 to 50 watt range.
For example
The L96 speaker is rated at 250 watts. The LE10H woofer has small theile parameters that rate it @ 75 watts, the LE5 is rated at 25 watts and I am unsure of the rating for the tweeter, but suspect it to be in the 15 watt range ( more help in this area anyone?) This is because as frequency increases you require less power to achieve a given sound pressure level. Your 250ti is a wonderful speaker. (wish I had a pair) hope you get your diaphragms replaced soon.

150a/250ti
01-31-2005, 02:22 PM
This is what my deal looks like so far. Thanks Hector I get it now.