What's wrong with my speaker? (soundclip)

jumblemind · #1 03-01-2013, 07:46 AM

I have a quick clip I recorded with my phone to capture a distorted buzzing coming from my Ampeg SVT 15e cabinet. I bought it off of craigslist last summer from a guy who had replaced the speaker with a 4ohm Celestion neo rated to 600w. I was running an Ampeg B2r through it at one gig this past December where I really had to crank the head to try and get volume for the room I was playing, and I'm pretty sure the speaker was farting. I'm not exactly sure what that sounds like, but the bass tone was pretty distorted. I played a couple of gigs after that with different amps and didn't notice anything out of the ordinary, but now I'm getting this sound.

Speaker does pass the 9v battery test. Is this a voice coil problem, or maybe something else in the cabinet? Solder connection? Do I just need to get a new speaker?

The sound is a 75 P Bass > LMTube > cabinet, at low volume. Skip to the 10s mark:
https://www.youtube.com/watch?v=d_IaPf3eqGA

drewish927 · #2 03-01-2013, 07:52 AM

Does it buzz or rattle more on certain notes? It might just be the sound in the video, but it almost sounds like there's something loose, perhaps a screw or two holding the speaker in? Maybe not, but when trouble shooting I always start easy and progress from there. Check to make sure all connections are secure and all screws are tight.

**bass4worship** · #3 03-01-2013, 07:58 AM

Might be a loose grill or screws on cab or speaker torn.

jumblemind · #4 03-01-2013, 08:02 AM

At first it does sound like something rattling. I had taken off the grill to check all the screws before this recording and hadn't secured one of the grill corners all the way back to the velcro dot, but this sounded like it was coming from "behind" the speaker when I got close with my ear. It sounded like the signal itself was distorting. Didn't notice a tear immediately, but I've never looked at a bad speaker before to know what I'm seeing (or hearing).

**bass4worship** · #5 03-01-2013, 08:16 AM

If you still hear it remove the speaker and if the wire is long sit it on the cab and play it. Any bad sounds speaker if not wires could be touching side of speaker.

Dbassmon · #6 03-01-2013, 08:21 AM

Could be wire touching the driver, not likely.
Could be something not tightened down, probably not.
All these are possible.

My guess....
Voice coil in the driver was probably heated from a clipping power amp, has changed size and now buzzing against the housing.
If you push the driver gently inward, do you feel friction?

If this is the case, that driver will need to be re-coned with a new voice coil. Less expensive than a new driver and will be good-as-new if done professionally, with OEM parts.

Here is a place, right in your area that will re-cone your speaker. Ampeg uses Eminence if it is the OEM speaker.
http://www.advancedsound.com/56k/the_co.htm

BassmanPaul · #7 03-01-2013, 10:59 AM

Quote:

Originally Posted by bass4worship

If you still hear it remove the speaker and if the wire is long sit it on the cab and play it. Any bad sounds speaker if not wires could be touching side of speaker.

Sorry but not such a good idea. With out a cabinet the cone will have nothing "supporting" it and can be easily damaged.

**bass4worship** · #8 03-01-2013, 04:34 PM

Quote:

Originally Posted by BassmanPaul

Sorry but not such a good idea. With out a cabinet the cone will have nothing "supporting" it and can be easily damaged.

Just don't play loud.

jaibeau · #9 03-01-2013, 04:41 PM

I feel your pain, I hate that kinda crap. It'll be something simple- good luck-

JimmyM · #10 03-01-2013, 05:06 PM

I don't know, bro...I've heard that sound out of fried speakers before. Take off the grill and gently push around the dustcap with even pressure using your fingers. If you feel rubbing, time for a recone or replacement.

jumblemind · #11 03-02-2013, 07:20 AM

I pushed on the dustcap, and there's not a real gravelly feel, but there's definitely some friction compared to my other cab speakers. I took the speaker out and the buzz is a lot worse. I reckon it's indeed fried.

I'll chalk it up to a learning experience, as the culprit incident happened right before I started diving into the amp FAQs here. I thought that since the speaker was rated higher than my amp's output wattage, there was no way I could blow it (WRONG), and that a single 4ohm 15 cab would give me more volume than a 8ohm 410 since I would get the full wattage (WAY WRONG/CONTRARY TO PHYSICS WRONG). All classic newbie assumptions held by a guy in his late 30s that's been playing bass in bands since he was 13, haha. Oh, well. Some of us do it the hard way.

jumblemind · #12 03-02-2013, 07:27 AM

Quote:

Originally Posted by Dbassmon

My guess....
Voice coil in the driver was probably heated from a clipping power amp, has changed size and now buzzing against the housing.

This. In the culprit incident I had the amp gain nearly dimed.

Quote:

Originally Posted by Dbassmon

If this is the case, that driver will need to be re-coned with a new voice coil. Less expensive than a new driver and will be good-as-new if done professionally, with OEM parts.

Here is a place, right in your area that will re-cone your speaker. Ampeg uses Eminence if it is the OEM speaker.
http://www.advancedsound.com/56k/the_co.htm

Thanks for looking that up! I would have never thought about it. The speaker is a 4ohm Celestion, one that the last owner dropped in there. It's probably less than a year old. I have no idea how it sounds compared to the original Eminence driver in the SVT 15e, but it sounded good enough to my ears. I kind of like the idea of going back to an 8ohm speaker, but I like this cab's weight with a neo and I'd hate to do a guessing game for a new speaker that's a good match for the cab's tuning.

Any recommends? Or should I stick with the Celestion and see about reconing here in town?

ldervish · #13 03-02-2013, 07:58 AM

Maybe Billfitzmaurice, greenboy or one of the other cab gurus will chime in...

Tvrtko · #14 03-02-2013, 08:56 AM

I had this case some times ago. I found buzzing cabinet itself IN THE CORNER! 2 sides of the cabinet were not glued together well. Tolex was covering outside. So you could not see it. I used sound generator to generate exact frequency when buzz starts and than went into frenzy search for the source of buzz.
When I found it, I pulled speakers from cabinet, used 1x1" piece of hard wood, cover it with glue and screw it in all corners of the cabinet.

You just got to know what you do. This sounds like cabinet buzz to me.

mystic38 · #15 03-02-2013, 09:00 AM

ABSOLUTELY go back to the stock speaker... removing one speaker and replacing it with another just because it has the same size and rating is a recipe for disaster..
A drive unit MUST be matched to the cabinet volume..and so the only one you know this is true for is the original speaker.

Quote:

Originally Posted by jumblemind

The speaker is a 4ohm Celestion, one that the last owner dropped in there. It's probably less than a year old. Any recommends? Or should I stick with the Celestion and see about reconing here in town?