THE Crossover Thread

[Gepetto]

First time removing a tweeter diaphragm, not bad.
Voice coil on diaphragm is good, no rub marks.
Resistance is being added at the loose rivet attaching the Faston terminal. Going to solder these rivets to the Faston. Both tweeters have one loose rivet.
The misalignment isn't in the magnet or the innermost plate, and doesn't affect the voice coil gap. Appears to be only the outermost plate, which appears to be structurally sound. No gentle tapping with wood block and hammer will move it into alignment. Appears manufactured this way. Very strange.
Going to do some more reading on these and the possiblity of newer tweeters.

Magnetically it does not matter...

 

[George S.]

Got"em reassembled and tested with the DDS Signal Generator controlled by the software on the Lenovo. It's driving the Akai integrated amp that's powering the tweeters.
Tested them from 3.5 KHz to 20 KHz in small steps and used the balance control at each step for comparison between the two tweeters.
Good news is they seem to be working very well and have similar output.
Bad news is me and my wife's hearing doesn't register above 10 KHz. Guess it's to be expected given that we're in our 60's. Oh well.
I'll reinstall these.

 

[Gibsonian]

Got"em reassembled and tested with the DDS Signal Generator controlled by the software on the Lenovo. It's driving the Akai integrated amp that's powering the tweeters.
Tested them from 3.5 KHz to 20 KHz in small steps and used the balance control at each step for comparison between the two tweeters.
Good news is they seem to be working very well and have similar output.
Bad news is me and my wife's hearing doesn't register above 10 KHz. Guess it's to be expected given that we're in our 60's. Oh well.
I'll reinstall these.

I'm not interested in that test, and I'm right behind you at 58. Right now, am ok not facing facts such as these!

 

[grapplesaw]

Got"em reassembled and tested with the DDS Signal Generator controlled by the software on the Lenovo. It's driving the Akai integrated amp that's powering the tweeters.
Tested them from 3.5 KHz to 20 KHz in small steps and used the balance control at each step for comparison between the two tweeters.
Good news is they seem to be working very well and have similar output.
Bad news is me and my wife's hearing doesn't register above 10 KHz. Guess it's to be expected given that we're in our 60's. Oh well.
I'll reinstall these.

mine rolls off after 10-12k to nothing as well

 

[mr_rye89]

I can still hear past 15khz at 34, not that useful unless you work on old picture tube TVs......

 

[laatsch55]

I was testing some DE-10's the other day for trhe K's. was using the AP for a source and a 400 for the amp part. I'm good to 15 with a gentle rolloff after that...

 

[mlucitt]

My tinnitus starts at 13kHz with a peak at 45.5kHz then everything becomes very quiet.

 

[George S.]

Yeah, after 10 kHz and higher the frequency seems to be over shadowed by the constant white noise I hear. I'm guessing tinnitus. Wife says the same thing about her hearing.
But. On further thought.
Think I'll do some more testing tomorrow with the same setup adding a MiniDsp Umik-1 mike and REW.
Was using the wife to verify what I wasn't hearing.
Need to verify it's our ears and not the drivers(pretty sure it's our ears). Later y'all.

 

[Skratch]

Sometimes I have selective hearing

 

[George S.]

After testing from 3.5 KHz to 20 KHz. Not bad for over 40 year old units.
The dip may be in the test equipment rather than the tweeters since both exhibit it. More investigation is needed.
The graph represents SPL (sound pressure levels) picked up by the Umik-1 mike.

 

[J!m]

The dip could be in the mic as well.

Everything has to be calibrated to do fine testing.

 

[George S.]

The dip could be in the mic as well.

Everything has to be calibrated to do fine testing.

I agree. I did load the mikes calibration file into REW. The dip could be anywhere.
On sound cards it's easy to run a loop back test to look at linearity.
I'll have to think about having the old Akai in the mix.
The issue is most likely there. Unfortunately I don't have any extra different tweeters laying around to test against.
I'm not going to worry about it, especially with my hearing issues.
It's all good!

 

[Gepetto]

Sometimes I have selective hearing

We all do Mark, it is a blessing...

 

[J!m]

…and a curse.

 

[George S.]

These big ass crossover boards were mounted on the back wall surrounded by yellow fiberglass sheet insulation. Removing them left a big area with no insulation.
They didn't do a great job gluing the insulation down way back in 1978. It was all dirty and separating. So scraping it all out and reinstalling new.
Got the 3 speaker jacks installed in 3/4" plywood, better than original. JBL used fiberboard glued and stapled to the cabinet.

 

[Louie3]

Damn, that's a whopper...I have moved the xovers outboard on a couple different box speakers...thought it made a difference.

 

[George S.]

First sweeps of the MinDsp 4X10HD and the JBL 150's, no analog crossovers, only digital. 1/6 smoothing and NO correction. The dips at 20 Hz are the subs crossover roll off. Also have dips at 80-100 Hz, the roll off between the subs and woofers crossovers. The subs and woofers are also in separate cabinets. Looks way better than I expected.
EQ and Time Alignment are next. Lots I need to learn, so this is going to take a while. Yup, I'm back on YouTube watching videos about the finer points of REW.

 

[Gibsonian]

Are you using usb mic for REW George? I think I need to start using REW as well

 

[George S.]

MiniDsp Umik-1.

 

[George S.]

Here's a good video to get started using REW. This is probably the best way to get started sweeping speakers.
I spent the afternoon running multiple sweeps, and have it down. Now I need to watch videos about the finer points of generating the filters correctly.
REW is the "Swiss Army Knife" of sound testing software and it gets complicated quickly.