Old guy wants to know??
Pat, Curios about what Low Pass crossover you are using on the Just Big & Loud 2225? (Sorry, couldn't help myself!) It has been many years, but I seem to remember having to build a trap to smooth out the upper midrange of the 2225. Unfortunately, don't remember the frequency center of the peak. That was in addition to the second order low pass filter set around 450 Hz. Are your 2225's current production or on the older side? Say 10 years or older?
Pat, Curios about what Low Pass crossover you are using on the Just Big & Loud 2225? (Sorry, couldn't help myself!) It has been many years, but I seem to remember having to build a trap to smooth out the upper midrange of the 2225. Unfortunately, don't remember the frequency center of the peak. That was in addition to the second order low pass filter set around 450 Hz. Are your 2225's current production or on the older side? Say 10 years or older?
My museum pieces of JBL 2225H are date coded 1982. They dont show any signs of abuse, saging, discoloration or so.
i started the first crossover layout (i had to start somwhere isnt it ?) with the 4671 cross over layout, 3.3mh and 60uf cap. i increased the inductor to 5.6mh for now. i must say yesterday late at night i made some good improvements, but as you say there is a sudden bump in the mids, regardless of the horn. but for now it is relatively pleasant with some EQ's tweaks.
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Dare?! Ditch the attitude...........
Anyway, I admit to a bit of confusion, what with various alignments being bandied about, but based my response on no small amount of box design experience in general and with JBL's 2225 and Altec's more powerful 3156 variant in particular, then used HR to sim a 5 ft^3 net/~40 Hz Fb alignment @ 100 W to prove it, so load up HR and IMPORT the attached RECORD to view all the data.
In scanning the thread I saw nothing to indicate you had simmed at desired power, only saying you were going with a 4", implying you hadn't.
6" is the smallest size for the commonly recommended 5% max vent mach [~344 m/s*0.05 = ~17 m/s], so if planning for the 2225's 200 W peak rating it will need to be somewhat larger.
GM
Bummer, I knew stuff was somewhat higher across the border, but this is ridiculous. Dual 4" is 'only' a ~5.657" dia., but still a lot better than 4".
GM
Yeah, this is a mid-bass horn driver, so lots of top end 'snap' that needs shelving, then level matching the horn to it using CD horn EQ to finish it off up high.
Makes a 'kick-a$$' 'vintage' prosound/HT mid-bass BR too in a Vas/1.44, Fb = 0.56*Fs alignment.
GM
Take a look at the woofer response from manufacturer! You see that response rises at mid region and is weaker at bass. Think about it and You will understand the purpose of crossover on bass driver. It has to equalize mid with bass, so has to start acting from rahter low. L-pad for tweeter does no do this.
So, 10 pages and still no FR plot (not even one done with pink noise and a smart phone) and only a schematic for the low pass.
As has been said on about every page so far: without measurements this isn't going to go anywhere. As the question has come up what measurements: actual in room respone, impedance plots and T/S parameters of the actual drivers.
As has been said on about every page so far: without measurements this isn't going to go anywhere. As the question has come up what measurements: actual in room respone, impedance plots and T/S parameters of the actual drivers.
it is just not available, thats it. i run the tests with a low power amp, i really doubt i will max out the 4" vent for now.
RTA/SPL test i do is with 1w/1m or even less, with a Audio Control SA-3050.
i dont need to push it to 200w for now i know already it is not right by ear and by measurements.
i will not reply anything further anywhere soon as i am waiting some cross over components (inductors and such) to make a better one.
Until now, have a good day
I’m surprised to see no new info or feedback on the advice already given. You have been given tons of advice in this thread on the limited info provided by you, I don’t get it why you have this attitude about it when we only try to advice the best we can to save you money and time. Hope your project will improve and that you end up happy after all but please don’t take your frustration from the bad design out on forum members trying to help you. If you don’t have time that’s fine you should perhaps not build your own to begin with, this hobby is about trial and error more than anything. Also if you lack the ability to take advice maybe not ask for it as it seems to have an impact on your ego too.
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