Testing a woofer

[John Webb]

Don't know if this helps. The 15-inch driver on my Ashdown was farting like crazy. Took it out and brought it to a tech who sign-off that there was nothing wrong with it. Mounted it on the cab and it would fart like hell. I then tried un-screwing the mounting screws while a looped note was being played through it. The farting noise slowly went away. So I tried something different. I put the cab on its back (with the drivers pointing at the ceiling) and took out all the mounting screws and the driver was playing as clear as ever. Turns out that over-tightening or an uneven tightening of the mounting screws on the cab caused the stamped steel speaker basket to distort, and this caused the farting sound. With the cab on its back, I then mounted the driver and tightened the screws evenly in a criss-crossing (star) pattern (the same way you would tighten the lugs on a wheel as you mount them on your car). This won't cost you a cent and is something you might want to try.

Thanks man, this was the first thing I tried......no improvement.

 

[John Webb]

I noticed that the midrange and tweeters are 8 ohm units and the Woofer is 4 Ohms. The crossover is selectable 4-8 and set to 4 Ohms.
Is this OK or should all 3 drivers be 4 Ohms?

 

[billfitzmaurice]

I noticed that the midrange and tweeters are 8 ohm units and the Woofer is 4 Ohms. The crossover is selectable 4-8 and set to 4 Ohms.
Is this OK or should all 3 drivers be 4 Ohms?

That depends on the crossover.

 

[John Webb]

Thanks to AL at US Speakers, he got Beyma to recone the woofer no charge. Now I have to figure out/straighten out the rest of the cabinet.

 

[BassmanPaul]

Unless you ensure that the Beyma will actually work in the Dr B cabinet you'll soon be back where you were.

Paul

 

[T-Bird]

Hi.

Unless you ensure that the Beyma will actually work in the Dr B cabinet you'll soon be back where you were.

Paul

^This, most likely.

Plus, if there's some debris in the magnet or the frame is bent, You'll be at square one again. Fortunately it won't cost You much, and the reconer will measure the basket beforehand so no loss for them either.

Regards
Sam

 

[John Webb]

I will take it slow.
Make sure the x over matches the drivers and that the port baffle is tuned for the Beyma.
I'm in no hurry, it is to be my spare.
thx