BillFitzmaurice.info

Quarterly update!

I took it too work again for some other techs who hadn't experienced it before.
One of them is a outlaw ham radio guy who knows a little about sound. We got to the crowd choice part of the program and he requested a "sweep" knowing the other guys didn't know what what was and he thought it would be funny to bust their ears.

I dialed up a 30hz to 20hz sweep on a app I have (that I have never used) and held the volume UP button on my phone to the max...
It played the sweep and we all laughed at how stupid that was.
The next request wàs Michael Jackson Thriller and as I turned it up to about 7 it started for lack of a better term chopping the sound, maybe oscillating on off of the playback.

I tried a bunch of stuff thinking it was the app, the Bluetooth connection etc. but I couldn't fix it.
Low to mix volume it was fine. But after 5-6 of 10 I'd say it messes up.
I took it home reloaded the tune in the software and tried again, still broken... I tried tuning the tune, but nothing helped except it seemed like muting the tweeter. I tried disconnecting the tweeter which worked but obviously no tweeter sux.
I ended up deciding the amp was messed up. I contacted PE and explained what happened, the Tech agreed I might have exceeded the amplitude or some such and could have damaged the amp, he sent a new one out pronto and I replaced the amp loaded the tune to get the exact same results...
I created a completely different tune and it's still there.

So I'm at the point that either the tweeter died so I took it apart and didn't see anything obvious wrong.
I kind of abandoned it out of frustration but I was thinking the other day what about the protection cap? Could it be damaged and shorting the amp somehow?

I am ready to just buy a new tweeter and cap but I don't like throwing parts at stuff.
Any ideas? If I'm gonna get new anyway I may just pull the cap and test it it as is, if it blows the diaphragm no loss.

Protection cap?

The next request wàs Michael Jackson Thriller and as I turned it up to about 7 it started for lack of a better term chopping the sound, maybe oscillating on off of the playback.

Have you tried to replicate this on another device(not the sweep, though)? This would test your phone for being the problem. Have you tried other tunes?

Bill Fitzmaurice wrote: ↑Tue Sep 26, 2023 8:53 pm Protection cap?

The 10uf cap I installed in series earlier in the build that I thought was to protect the tweeter from errant frequencies that could damage it.

Tom Smit wrote: ↑Tue Sep 26, 2023 9:48 pm

The next request wàs Michael Jackson Thriller and as I turned it up to about 7 it started for lack of a better term chopping the sound, maybe oscillating on off of the playback.

Have you tried to replicate this on another device(not the sweep, though)? This would test your phone for being the problem. Have you tried other tunes?

Yes, I have used several devices that all previously sounded perfect.

Yes, I created a completely new tune from scratch, obviously this was not EQ'ed to the level of the original but the tweeter didn't seem to care through out the build. At this point with a new amp/bluetooth receiver there is nothing retained in the signal chain.
I even ran it off line in cable no bluetooth at all.

I ran the power supply section off a AC/DC power supply removed all the battery power equipment with no change.
With no proof it seems like something is clipping the output.

CarterKraft wrote: ↑Wed Sep 27, 2023 7:06 am The 10uf cap I installed in series earlier in the build that I thought was to protect the tweeter from errant frequencies that could damage it.

I doubt that it's damaged. Caps tend to either work fine or not at all. You've got clipping somewhere. It could be the amp, could be the source media. Clipping is always first heard in the high frequencies.

I'm at a loss as to where to go next. The amp/receiver board is completely new.
I suppose I could swap the mid and tweeter channel but a new complete unit should have tested that.

This "clipping" effects the low and mid but if I mute in software or just disconnect the tweeter it doesn't clip.

I am thinking the tweeter is busted and is shorting somehow? Sounds that way from my own explanation.

Weldon, do you have any compressors or limiters in your DSP signal flow path?

CarterKraft wrote: ↑Wed Sep 27, 2023 9:31 am This "clipping" effects the low and mid but if I mute in software or just disconnect the tweeter it doesn't clip.

I am thinking the tweeter is busted and is shorting somehow? Sounds that way from my own explanation.

It does seem to point this direction. Are you able to disconnect the tweeter and measure DC resistance across the speaker terminals?

Seth wrote: ↑Wed Sep 27, 2023 12:20 pm

CarterKraft wrote: ↑Wed Sep 27, 2023 9:31 am This "clipping" effects the low and mid but if I mute in software or just disconnect the tweeter it doesn't clip.

I am thinking the tweeter is busted and is shorting somehow? Sounds that way from my own explanation.

It does seem to point this direction. Are you able to disconnect the tweeter and measure DC resistance across the speaker terminals?

Yes I can do that. I feel like I should have done that already but can't remember doing that

I ordered a Dayton NEO 1" tweeter to test, not the correct part per the plans but will let me test and I will use it for another project I'm sure.
I need my TallBoy back!

https://www.parts-express.com/Dayton-Au ... quantity=1

Seth wrote: ↑Wed Sep 27, 2023 12:13 pm Weldon, do you have any compressors or limiters in your DSP signal flow path?

No I didn't the only DSP I had in there was the dynamic bass module on the woofer.

But I got rid of all that stuff when I made the from scratch tune, only crossovers.

CarterKraft wrote: ↑Wed Sep 27, 2023 2:08 pm

Seth wrote: ↑Wed Sep 27, 2023 12:13 pm Weldon, do you have any compressors or limiters in your DSP signal flow path?

No I didn't the only DSP I had in there was the dynamic bass module on the woofer.

But I got rid of all that stuff when I made the from scratch tune, only crossovers.

That rules out limiter pumping.

Because I'm too lazy to dig back through 250 posts.......what is the mixer/amp configuration? You said receiver - is that what your using? I wouldn't go changing components in the cab until you rule out the signal getting hammered somewhere.

Almost every time a venue calls me because they say the speakers are distorted - it's because they are overdriving the input. I turn down the input, turn up the output and voila.....same volume with no distortion.