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View Full Version : SR4725X no midrange



clubman
09-10-2007, 08:20 PM
Just finished my home made SR4725X cabs today and got them all together and one cab. has no mids. I bypassed all my Eq,limiter, ect...and ran from the mixer to the amp. I even swaped channels on the amp, channels from my source, and changed source material. Still one is very low in the midrange than the other when paned L to R. I am using brand new JBL xovers from the SR4725X and 2226H woofs and 2425G horns. Have not yet tried to trouble shoot this as its geting late. Should I swap Xovers or woofers to see where the problem is?

Could a brand new xover be out of wack?

pelly3s
09-10-2007, 09:20 PM
it could be the crossover i would swap them first and see if the problem moves with the crossover. now is it low mids or upper mids that are the problem

Zilch
09-10-2007, 10:17 PM
2425G?

clubman
09-11-2007, 08:01 AM
2425G?

Sorry 2425J I was tired:blink:

My guess is that it would be uper mids...the range right before the horn comes into play. Seems like the 2226H is rolling off way to early.

Earl K
09-11-2007, 10:22 AM
Sorry 2425J I was tired

- Your 2425J driver has the wrong impedance diaphragm to work correctly with this 4725x crossover. Your crossover wants to see a 2425H driver ( which is a nominal 8 ohm load / a 2425J is nominally rated as being 16 ohms )
- It's little wonder you have some holes in the frequency curve ( near the crossover region ) .

Solution
- Buy a pair of 2426H ( or 2425H ) drivers from eBay ( they're typically cheap enough ) / then eBay what you presently own / or else / buy some 8 ohm ( JBL made ) replacement diaphragms .
- Don't ask us about the viability of using cheaper "knockoff" diaphragms as replacements .


My guess is that it would be uper mids...the range right before the horn comes into play. Seems like the 2226H is rolling off way to early.

- Don't guess, make some response measurements .
- If you're going to fool around with this stuff / buy some RTA software ( such as TrueAudios' "TrueRTA" ) so you can more accurately identify ( for yourself & us ) where things have gone wrong when you have design mishaps.

- & No , it's not worth your while ( or anyones' for that matter ) to attempt a redesign of the passive components in this crossover ( for your "J" drivers ). It'll be an exercise in futility .

Zilch
09-11-2007, 12:04 PM
Use biamp mode (with highpass protection for the HF) to determine if the problem is in the woofers or the mid/high drivers themselves.

clubman
09-11-2007, 12:34 PM
Both horns are 16 ohm....the problem follows the woofer when moved to the other cab. I checked the DCR on that woofer and it is 1.5 ohm. Yes RTA software is in the future but I could very clearly hear the differance with my ears. Didnt need software to tell me. Looks like recone time on that 2226H.

edgewound
09-11-2007, 03:40 PM
Both horns are 16 ohm....the problem follows the woofer when moved to the other cab. I checked the DCR on that woofer and it is 1.5 ohm. Yes RTA software is in the future but I could very clearly hear the differance with my ears. Didnt need software to tell me. Looks like recone time on that 2226H.

Very good....you figured it out:applaud:....

Though EarlK is right about the impedance/crossover mismatch. You can just replace the diaphragms to D8R2425...but the labels won't match.

clubman
09-11-2007, 08:41 PM
Though EarlK is right about the impedance/crossover mismatch. You can just replace the diaphragms to D8R2425...but the labels won't match.

Yes I am aware of this but at the time I dont want to shell out the dough for 2 new 8ohm diaphragms. Ive talked to many people about this and they say its not a huge deal.(evan a autherized JBL service center) It sounds fine to me with the 16 ohm driver and its not used for critical playback. If they ever fail me I will replace with the 8 ohm...but for now its not worth it to me.