Axiom Home Page Forums General Discussion Technical Questions low freq. sweeps cause rattling from M60s

I was running Avia's calibration disc this morning (hey I'm snowed in, and it's tedious and fun in about equal parts). At one point, the test disk runs low frequency sweeps through each channel, one at a time. It starts at 200 Hz and works down to around 20 Hz. The VP-150 and the M60 I use for the right front did great within their spec ranges. The M60 I use on the left front also performed well except for one thing - I got a metal-on-metal rattling sound at many of the freqencies throughout the sweep, even at some of the relatively high freqencies (i.e 150 Hz). I hope that it just means there's a screw somewhere that needs tightening... but I've not really ever been a take-it-apart guy, so I don't even know where to begin or what to do.

Any thoughts?

Try tightening the drivers. I had a similar situation a few months ago.

PM me if that doesn't work. I can fill you in with what my issue was. This is for the respect I have for Axiom and the owners.

(also via PM)

Thanks. They're now as tightly screwed in as I can manage, and that reduced it some. But there's still some distinct rattle, particularly at specific frequencies and less so but noticeable at various frequency ranges. I think I've also isolated the problem, physically, at the upper of the two woofers, just from getting right up next to the tower while it was playing.

I'm still in my 30 day, so even if the problem is a real issue, I at least should be able to exchange it, no problem. But since I suspect it's just something loose, it should be fixable from home.

engine_joe,
forgive me if tleigh had already mentioned this in the pm, or if you've tried it yourself already, but have you tried tightening the binding posts? Just a thought but it could be that simple.

I would give Axiom's wonderful customer service a call. They will probably send you a couple of drivers to fix this. It will take five minutes to fix .
What crossover freq. are you using?

Checked the binding posts, and they're ok, but thanks for the suggestion! Guess I'll give Axiom a call; they'll certainly have some ideas.

Oh, and my crossover is set at 60 Hz. It generally seems to be smoothest for the music and films I've tested with.

Please keep us posted.
Good luck!

Tom

Keep in mind frequency sweeps are not (often) found in music, so the chances of regular program material exciting those same resonances are slim. Still, now that you know it's there, it'll probably bug you until you know it's gone.

You might try pulling the drivers out one by one and repositioning the wires a bit. One wire pair could be touching and buzz against each other at specific frequencies.

This is what I went through: Here

I really didn't want to dig it up but thought it might help.

Alan (I think) mentioned that sometimes the speakers get banged around in shipping enough that an internal wire ends up touching the inside of the cabinet and buzzing at certain frequencies. IIRC the solution was to remove the driver from the front and move the wire.

I always had a problem with this when building speakers -- if you keep the wires short enought to never touch the sides then they're too darned short when you try to take them apart.

I ended up trying elastic bands as tensioners for the wires -- works OK if you solder the connections but bad news if you use push-on terminals

Good Point! I forgot about that.
Hot glue works great too on the internal cabinet wiring.

I forgot about hot melt. Don't think hot melt guns had been invented when I was building speakers

We used hot melt in our white box pc's (before Dell ). It would save us a call from a customer that was afraid to open up the case and check the cables.

I just went through this myself with my M50’s. I was having problems at about 200 Hz.
After talking to Axiom they had me tighten every thing up. I really had to crank on the screws but it fixed the vibration. But you have to be careful not to strip out the screws either.

If you do have to take the screws out, I have a tip for you.

Put the the screw in the hole and turn it backwards until you feel the screw drop down a little bit. Then, turn it forwards again to tighten it down. This ensures that the screw uses the same threads that were already there. If you don't do this, you might cut a second, or even a third set of threads.

This also works for sheet metal. On metal and hard wood, you can usually here a click when the screw drops into the original threads. On softer woods, you have to feel for it.

When putting the screws back into the Axiom drivers, use your fingers to insert the screw. Use the turn backwards technique, and then after you have the screw started 2 or 3 threads with your fingers use the allen wrench. Allen wrenches scare me around dviers because the design of the tool almost forces you to have off center pressure. Be careful.

Thanks for the suggestions - I'm also slightly nervous about the allen wrench issue, but I think it'll be alright. I'm actually not going to do anything until tomorrow after I can talk to someone at Axiom, as he/she/they may have their own ideas or less invasive suggestions perhaps (even if unlikely). Didn't really matter this afternoon/evening - football games aren't particually aurally challenging - so I decided to wait to do a dissection beyond what I've done thus far.

Again, thanks for the tips, and I'll keep you all posted on developments. Given Axiom's customer service reputation, I'm sure it'll be sorted out quickly!

Update:

I communicated with Brent at Axiom, who in turn talked to Joe VaSSallo. Long and the short of it is, they think the magnet might be loose in the driver, and they're sending me a replacement driver to try.

All I can say is - great customer service, I continue to be impressed, even after all the stories! I will update again after I install the new driver and we'll see what's what.

Update 2: Axiom sent me the wrong driver. They semt me the 5.25" dedicated mid, and I need to replace one of the 6.5" woofers. So it'll be a little more time before I can get rid of the rattling.

Playing music, I do notice it sometimes, since it seems to ring out the most in the 100Hz - 150 Hz range, and plenty of music low end crosses through that zone. So it's frustrating, but the speakers sound great otherwise.

So the wait continues...

Final solution: new woofer arrived this evening, and the M60 is now great! No ratling metallic sound (except when the room shakes! ).

Thanks everyone for their suggestions, and thanks Axiom for their great customer service!

P.S. - So great, in fact, that they let me keep the 5.25" driver they sent by accident as a spare, since they asserted it was their fault for sending me the wrong driver!

So... a few minutes with a hole saw and you could be well on your way to having an M80... at least on one side... at least for the midrange... OK, maybe just keep it as a spare.

Glad to hear everything worked out.

In reply to:

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they let me keep the 5.25" driver they sent by accident as a spare

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i think i know someone with a clock radio that needs some alteration.....?

bigjohn

it will be the "Axiom Wave Radio" you can sell for $1200.00.NICE.