Blown tweeter...or crossover? Best testing methods?

[KevInDaBassment]

L Pads need to match the impedance of the driver as they maintain the impedance the crossover sees as you turn it down to keep the crossover frequency the same.

The driver as in the Tweeter or the Woofer in this particular cab? The tweeter is 8 ohm, but the woofer is 4 ohm. The cab reads as ~4ohm on my multimeter. It's working now up to zero attenuation on the tweeter, only change I made was moving it to the other wall.

Outside of some multimeter readings and soldering leads, I can't say I've got much electrical experience so that's an honest inquiry on my part. What should I be looking out for other than the distortion coming back? I definitely don't want to cause any more damage to it, but I bought the cab used for $180, so I'm not exactly itching to fork over $100 in bench charges to check it lol

 

[agedhorse]

Is it possible that something in the room was vibrating, causing the symptoms that resolved by moving the cabinet?

 

[KevInDaBassment]

Is it possible that something in the room was vibrating, causing the symptoms that resolved by moving the cabinet?

The second time around there was a distinct volume difference (master volume had to be turned up noticeably higher) to get anything to kick in, then I was getting distortion on both until I moved the cabinet to the other wall. Then I was getting proper volume and no distortion at a usual nudge of the master volume knob.

I couldn't say for 100% sure (it's a rental house), but the first time around I'm pretty sure it was the tweeter distorting, since I was about 3 ft away from it when I heard it. Moving closer to it still yielded the same perception.

Maybe this was luck of the draw or something? I'm also wondering if I jostled something while moving the cab and/or reseating the 1/4" plug after moving it did something too. I tried that initially, but I guess the combination of the two did something? I don't plan on gigging the cab (it's a practice cab only), this possibility will definitely be at the forefront of my mind if I ever decide to though.

Replacement Speakon plate (OEM direct from Avatar) is around $100, wondering if it's the 1/4" jacks all along. I'd put the speakon jacks in myself, but the plate is only sized for 1/4" and I don't have any metal drilling bits that are up to the task of widening them

 

[agedhorse]

The second time around there was a distinct volume difference (master volume had to be turned up noticeably higher) to get anything to kick in, then I was getting distortion on both until I moved the cabinet to the other wall. Then I was getting proper volume and no distortion at a usual nudge of the master volume knob.

I couldn't say for 100% sure (it's a rental house), but the first time around I'm pretty sure it was the tweeter distorting, since I was about 3 ft away from it when I heard it. Moving closer to it still yielded the same perception.

Maybe this was luck of the draw or something? I'm also wondering if I jostled something while moving the cab and/or reseating the 1/4" plug after moving it did something too. I tried that initially, but I guess the combination of the two did something? I don't plan on gigging the cab (it's a practice cab only), this possibility will definitely be at the forefront of my mind if I ever decide to though.

Replacement Speakon plate (OEM direct from Avatar) is around $100, wondering if it's the 1/4" jacks all along. I'd put the speakon jacks in myself, but the plate is only sized for 1/4" and I don't have any metal drilling bits that are up to the task of widening them

You don't want to drill a hole that size anyway, it's much more safely done by punching.

 

[Mike Caldwell]

"master volume had to be turned up noticeably higher) to get anything to kick in"

With that statement it sounds like a very intermittent connection that is almost making connection, the higher "jump start voltage" from the amp being turned up kind of arcs through the dirty, oxidized, ect connection and it will work for a while.

Speakons take a 15/16 size hole, taking the plate out and having it drilled with a drill press would be better and your not going to get metal shavings inside the cabinet.

 

[agedhorse]

"master volume had to be turned up noticeably higher) to get anything to kick in"

With that statement it sounds like a very intermittent connection that is almost making connection, the higher "jump start voltage" from the amp being turned up kind of arcs through the dirty, oxidized, ect connection and it will work for a while.

Speakons take a 15/16 size hole, taking the plate out and having it drilled with a drill press would be better and your not going to get metal shavings inside the cabinet.

Clamp that mother tightly or you may end up wearing it internally.

 

[Hoochie Coochie Man]

If I wanted to enlarge an existing hole to 15/16" I would leave the jack plate attached to the cabinet and use a step drill that goes to 7/8" and a round file to do the job. You could probably get by with an inexpensive one from someplace like Harbor Freight if you don't want to pay what a Klein, Greenlee or other good one costs.

step drill bit

 

[agedhorse]

If I wanted to enlarge an existing hole to 15/16" I would leave the jack plate attached to the cabinet and use a step drill to do the job.

step drill bit

Step drills and powerful drill motors can result in broken wrists. My 1/2" high torque low speed shop drill is fully capable of doing so.

 

[Hoochie Coochie Man]

Yeah, you need to take care. Also don't spin a large diameter drill bit at high speed because even a good one will over heat and be ruined. Don't forget to wear eye protection as well.

 

[Mike Caldwell]

Clamp that mother tightly or you may end up wearing it internally.

Yes, I screw plates to a piece of wood and clamp that to the drill press table.

 

[Redbrangus]

I never had a shop class or even an older relative to show me how to use stationary power tools correctly -- a lot of what I know about using tools I learned the very hard -- and exceptionally dumb -- way, by making mistakes. Between the table saw and the drill press, I'm VERY lucky to have all my parts, and I don't recommend that method. I had a friend whose career as a banjo and bass player came to a halt after he clipped off two fingertips on his left hand with a table saw -- luckily, he also played tuba.

A step drill is a gnarly way to make or enlarge a hole, but I'll confess to having done it when there weren't any other options. If one is determined to enlarge an existing hole on a jack plate, it pretty much HAS to be removed from the cab -- you don't want metal shavings falling into the cab, even if the plate is aluminum rather than steel. (It seems steel filings falling down into the cab will inevitably result in some little piece ending up in the gap of one of the drivers.) It can't be emphasized enough that the workpiece has to be clamped down really well and the drill should be turning at the lowest speed. You can maybe get away with using a step drill bit in a handheld drill with aluminum, but I don't advise it when drilling steel. As per usual, @agedhorse's advice is the best -- a chassis punch is the proper way to make a connector hole in a jack plate.

 

[Hoochie Coochie Man]

Redbrangus. I used to do field service work that often required making holes in electrical enclosures, and I have probably made hundreds of such holes. One reason I suggested a step drill is that a cheap one for a one-time use would be much less costly than a punch. Also, when I stated that it could be done with the plate attached to the cabinet, I did not elaborate as I should have done about ways to do it without any chance of metal shards actually getting into the cabinet. So, I will acknowledge your mention about metal shavings, but it can be easily done. I have an extensive set of Greenlee punches, but there were times out in the field when I chose a step drill because it would be quicker than a punch. Personally, I don't think a step drill is a scary tool, but I can see where someone who is not experienced in such things should be cautioned to take care if they have not done this type of work before. I have seen people think that they have clamped a sheet metal work piece to the table of a drill press only to have it not be as secure as they thought. There are often many ways to skin a cat, just as there are many ways to get hurt, or have not so good results. I really appreciate all the good and knowledgeable folks who share knowledge here.