Roswell 7.0 Airborne replacement driver

[bdisney3]

I have a pair of Roswell 7.0 Airborne HLCD speakers on my tower - one (port side) is no longer producing proper "highs" - I think the tweeter is dead. Communicated with Roswell directly - cost of replacement driver is $400 and includes crossover network. Thoughts on if I should do this or put the $$ toward a replacement set of tower speakers? If so, what do you recommend? Amp powering the existing speakers is a Rockford T600-4ad.

[MLA]

Holly smokes, $400? I can rebuild a Rev-10 for less than that with parts direct from Wet Sounds. Mid-bass, x-over and compression.

You are a almost half way to a pair of Rev-8. Thats an 8" HLCD compared to a 6.5". You are a 3rd of the way to a pair of Rev-10. Your 600.4 will do either just fine. Brand aside, there is no comparison between a 6.5 and an 8" and not even in the same galaxy as a 10" HLCD.

[swatguy]

I am with MLA , as hard as it will be to ditch one of the best looking housings to date I say put the 400 towards some Rev's you'll appreciate the sound. Maybe even talk w Roswell see if they'll hook you up with a Discounted Neptune 8 instead of the driver

[MLA]

The Neptune 8 is $1450 retail! Even at a discount, you'd still likely be more than a pair of Rev-10 and have a smaller mid-bass driver and smaller compression driver.

[David Analog]

I've never considered Roswell to be a real audio company. Nothing here changes my opinion.
Pull the speaker apart in an attempt to identify the tweeter. Compression tweeters are somewhat generic. You might be able to find a suitable replacement part from Part-Express for under $75, or just the tweeter diaphragm/voice coil for under $25. And you have the other good tweeter available if measurements are needed. If it's a blown series capacitor in the passive highpass crossover you're looking at a $5 replacement.

[bdisney3]

I've never considered Roswell to be a real audio company. Nothing here changes my opinion.
Pull the speaker apart in an attempt to identify the tweeter. Compression tweeters are somewhat generic. You might be able to find a suitable replacement part from Part-Express for under $75, or just the tweeter diaphragm/voice coil for under $25. And you have the other good tweeter available if measurements are needed. If it's a blown series capacitor in the passive highpass crossover you're looking at a $5 replacement.

Hmm - didn't think about that. Good idea David! Anything in particular I should be looking for? I know what blown caps look like, but what else? Thanks for the suggestion!


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[David Analog]

Hmm - didn't think about that. Good idea David! [Anything in particular I should be looking for?] I know what blown caps look like, but what else? Thanks for the suggestion!


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Burnt tweeter voice coil winding, bad terminals or cold solder joints, unplugged disconnects, smoked cap, are what I would visually inspect. Those are the most likely issues. A multimeter may come in handy. You can't measure DC thru a cap but you can measure AC at a high frequency, say 5 kHz.

[bdisney3]

Burnt tweeter voice coil winding, bad terminals or cold solder joints, unplugged disconnects, smoked cap, are what I would visually inspect. Those are the most likely issues. A multimeter may come in handy. You can't measure DC thru a cap but you can measure AC at a high frequency, say 5 kHz.

Okay - all apart - think I found the issue. Appears to be burnt voice coil winding (diaphragm removed - note dark parts on what I assume is voice coil):


Here are a couple of other shots of the tweeter driver assembly - Top:


Bottom:


As you can see, no part number or markings of any kind. If I measure across the windings, it's exactly 1 3/8" (assuming I measure across the copper windings on the first pic?) If I measure across the diaphragm, it's exactly 1 3/4". The bottom of the driver (last pic) is 4 1/4" - alothough this looks like it may re removable based on the black countersunk screws. I think I may have found a replacement driver here: http://www.ebay.com/itm/P-Audio-BMD-...GkpJX71PhdgxDg

The only problem with the above driver - It only has three holes on the back for attaching, where as you can see in last picture above, mine has four. Maybe I should just look to replace the diaphragm/voicecoil assembly? Not sure if there would be other damage other than what is pictured in first pic to any other component? Here's where the diaphragm attaches if that helps:




Sorry for being so long winded - and thanks in advance for any pointers as I'm clearly in a little over my head!

[David Analog]

Verify that the impedance is the same and that the VC diameter is the same. No point in buying more than the replacement diaphragm/coil.

[bdisney3]

Dumb question probably - how do I verify impedance? I have a multi meter - just don't know what I'm testing for. Also what do I measure specifically for voice coil diameter?


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[David Analog]

You can't measure AC impedance but you can measure DC resistance. So close enough. The DCR will often measure a bit lower than the nominal impedance. So if you read 7-ohms, that's an 8-ohm voice coil. Reading the bad coil, even if it's not open, isn't likely to be accurate. So measure the DCR of the good tweeter, but across the unplugged tweeter terminals, and without crossover. The DC voltage of the multimeter should be too small to do damage. Just don't take all day. Use the DC resistance mode within the applicable resistance range.

[David Analog]

Oh, and while you are at it, you might inspect the good tweeter anyway. You'd hate to go through this only to find out a week later that the other tweeter was close to failure.
It would be so much easier to buy two diaphragms today.
Btw, those type tweeters aren't exactly fragile. So try and figure out what caused the failure so you don't have a repeat performance.

[bdisney3]

OK - the bad tweeter measures approx 2 ohms resistance - the good at 6.8 - the mid/bass driver also measures close to 6.8 - so guessing both are 8 ohms, which when wired in parallel, would produce a 4 ohm load (If I remember my parallel vs series wiring). The Roswell 7.0's are rated at 4 ohms - so safe to say 8 ohms it is, right? Also, how might I go about determining cause of failure? What would be common things other than over driven (cranked up too much)? Finally - I'm guessing to measure the VC I measure the "windings" that appear burnt in the first pic above? If so, they measure approx 1 3/8" = 35mm. After looking more carefully at the driver I posted above, I realized it bolts on with 3 bolts, not 4 as mine has. I am now thinking this is the correct driver: http://www.vortexaudioexpress.com/py...lt-pdb252.html or http://www.amazon.com/Pyle-PDB252-Al.../dp/B001581MN0

Not sure how I'd find just the diaphragm - so maybe I should just get this (it's only $23) - in fact maybe get two in case the other fails...

The size and impedance seem to match and they are 4 bolt (and the spacing of the bolts seems to match). Looking at the specs of the Roswell, it shows 35mm compression tweeters and 200W RMS/500W Peak where the driver linked shows 35mm 250W RMS/500W Peak - so that seems to match too. Thoughts? Thanks again David - really appreciate the guidance. You must be an engineer of some sort?

[David Analog]

Nope. Not at all an engineer. Although I went to MIT....Mistakes I Tried.
So I have taken you about as far as I can. The above order seems like a reasonable risk. Good luck.

[bdisney3]

Ordered two of them - I'll let you know (and anyone else who stumbles across this down the road). Hoping this works as a $25 fix seems like a way better solution than a $400 replacement driver/crossover resolution from the manufacturer. Taking the speaker unit apart was fairly easy - took may 15 minutes or so after removing the speaker from the tower...