1 Topic by NPB_EST.1979 (edited by NPB_EST.1979 2010-01-06 21:33:21)

  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Topic: Is my speaker is blown?

I have a marshall LEAD4x12 cab.

The upper left speaker makes music, but has a bit of a rattle (sort like when you flick a filament bulb) in the background of it. It occurs only when I hit certain bassy notes like an E chord, or a B note (a string 2nd fret). stuff like that it rattles a bit.

I don't know if it's blown, and here is what I did to check:

I took the speaker out of the cabinet. First I checked to see if it was loose, but it wasn't noticeably loose. So after I got the speaker out, I lightly pushed down on the speaker and listened for any papery or cardboard flapping onto cardboard sounds that would suggest a broken speaker. I could get nothing like that, but when I went down farther, it made (what I can only describe as) a sticky or smacky noise, like something was sticking to it, and unsticking again. Like putting a half wet lolli-pop on a table and pulling it off again. I couldn't get it to happen regularly, maybe once or twice every 10 or so pushes down on the speaker.

Does anyone have experience with this sort of thing?

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool

2 Reply by GoT MuLe 31788 (edited by GoT MuLe 31788 2010-01-06 21:48:47)

  • Registered: 2007-09-30
  • Posts: 556

Re: Is my speaker is blown?

Hey does it sound like this description.

Flabbing, Farting Out
Context: This speaker is really flabby.
Description: Flabbing, or Farting Out, is when the magnetic circuit loses control of the voice coil at high volumes on low bass notes. Since, with a big composite of tones, the mids and uppers are more or less supported by the low frequencies moving the cone in and out, the farting out can be very annoying and completely disrupt the structure and texture of your overall tone. Big magnets with tight gaps usually assure good, tight control of the voice coil under all conditions. Sometimes the speaker gets the blame for a problem that is occuring in the output circuit of the amp. Blocking in the output circuit from overdriving the output tubes, an unstable output circuit, and 120hz ripple components from the power supply on the signal can cause flabbing that appears to be a speaker problem.

I got it from this site: http://www.webervst.com/spterm.html#rub

Maybe you can pinpoint it - they have good explanations.

Ben

PS - Forgot to add, as a test try lowering you bass and/or gain to see if it goes away.

  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: Is my speaker is blown?

Ben,

I was really only noticing it when playing clean.

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool
  • Registered: 2007-09-30
  • Posts: 556

Re: Is my speaker is blown?

I don't have too much experience with speakers, I just know what Flabby/Farty speaker sound is, having heard it.  It could maybe be the voice coil rubbing, but I don't no what that sounds like, having never had or seen that problem.  Does it happen at high volumes only, low volumes, or both.  If it's high volumes, and you keep your bass up, I'd look into lowering that to see if it clears up.  If its at low or both volumes then IDK really lol.

Ben

PS - What kind of speaker is it?  Does it happen on other amps?

  • RickB
  • RickB
  • BONAMEGAMETAL
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  • From: San Diego
  • Registered: 2009-10-30
  • Posts: 12,198

Re: Is my speaker is blown?

Sounds like a misalignment of the voice coil in the magnet. The noise you get is the coil rubbing on the magnet at the limit of travel. My best guess. Rick

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  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: Is my speaker is blown?

GoT MuLe 31788 wrote:

PS - What kind of speaker is it?  Does it happen on other amps?

It is a Celestion 4x12" Celestion G12L 40W S800 speakers. 160 watts power handling capacity. Mono. 8 ohms.
http://www.lean-business.co.uk/eshop/im … L%20X4.jpg

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool

7 Reply by fuzzy wuzzy (edited by fuzzy wuzzy 2010-01-07 04:01:51)

  • Registered: 2008-04-02
  • Posts: 671

Re: Is my speaker is blown?

Nick are you 100% sure its the speaker thats rattling. I could tell you a story about a kid that bought a marshall slp 100 and played it thru a 2 x 12 ev loaded cab - sure enough a serious rattle developed, we both could have sworn that he broke a speaker by crankin that powerful amp. It took us about a week to figure out that what had happened was the sheer decible level of the dimed marsh had actually vibrated the walls so much in his music room that the 80 framed photos of our favorite guitarists had become loose and were now literally rattling at any volume level, it sounded like it was coming out of the cab when in reality - it was the room that was rattling.

Wierd stuff happens sometimes,
Jack

PS-Oh yeah, that kids name is Ben tongue

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  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: Is my speaker is blown?

I can try isolating it further, but my 'control' test was running a 15watt Fender Blues Jr. through it clean, and I still got some rattle. I guess now I should probably try to do it in a different room. At first I thought I was rattling the snare on the drumset. So I put that in another room.

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool