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Ampeg 810e making strange noise while playing lowest notes in drop a#

Discussion in 'Amps and Cabs [BG]' started by Eedwards7891, Jan 13, 2020.


  1. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    I bought an Ampeg 810e cab two years ago, and it has played amazing for me . Tonight at practice, we noticed a strange noise coming from my cab. It is a crackling , almost dirty pot sounding noise. It doesn’t sound like a farted out speaker .

    I was playing decently loud, using a Hartke LH1000 in mono. it was just under 3 on the volume .

    we checked the cables, checked with another bass, and checked with another 810 cab, and determined the noise was , in fact, coming from the 810.

    it seems to come from the center left speaker , but it’s more in that area than from the speaker for sure .
    We removed the grille, visually inspected each speaker while playing , everything looked okay. We gently and evenly touched the cones and the outer edges of the speakers to see if we could isolate it, the sound never went away . None of the dust caps look bad, and it looks entirely sealed up.

    I wasn’t able to dive in and try a bunch of stuff, but I did check all of the screws around each one of the speakers, they were all good and tight. I tried moving the cab and my head to see if it changed anything, it did not . We tried pushing on the wooden cross brace to see if it would stop then noise , and it didn’t .
    I’m unsure of what to do. I’ve read a lot of threads here, and I have a general idea that it may be a voice coil or cab rattle.

    any and all help identifying or fixing this is greatly appreciated .
     
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    That's a lot of power at such a low frequency for that cabinet imo. I would not be surprised if there was driver damage (possibly to all of the drivers) depending on the amount of good judgement and common sense used. Knob positions mean nothing.
     
  3. Wasnex

    Wasnex

    Dec 25, 2011
    Drop A#, so your talking a fundamental of 29hz. I think @ThisBass may have modeled the cab. Maybe he will comment on how much power it can reasonably handle at that frequency.
     
    Bassdirty, Squittolo and Eedwards7891 like this.
  4. Try the battery test for good measure. All speakers should jump in the same direction when you put 9V across a 1/4 cable.

    Dead ones still make sound when played thanks to the working one back pressure.

    I see a HPF in your future.
     
  5. Eedwards7891

    Eedwards7891

    Dec 11, 2017

    Thank you for the reply. I guess I figured an 810 pushed at low volume wouldn’t be risking any damage . I understand , drop A# is very low , and I typically don’t even play the lowest string .

    All in all, if it is voice coil damage, what is the prognosis? Is the cab basically trashed , for the sake of having to potentially replace all 8 speakers? Additionally, how do other bands get by with playing in drop A#? Would a ported cab or a larger speaker be a better option? I’m genuinely asking , I honestly don’t know . Thank you for your time .
     
  6. Eedwards7891

    Eedwards7891

    Dec 11, 2017

    I’m familiar with an HPF, but I’ve never heard of the battery test you recommended. How does it work? Do you put a 9v to the speaker cable and monitor the travel of the speakers ? Should they move ? During the test, will one move more than the other? Thank you for your time .
     
  7. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Perhaps you might benefit from some help by somebody (a qualified tech) to assist in the troubleshooting to determine what it really wrong?
     
  8. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    I would agree. I don’t believe there are any qualified techs in my town, but I have emailed the two music stores to get a recommendation. Thank you .
     
    agedhorse likes this.
  9. You briefly apply the 9v while watching the speakers. They should all jump outwards with + on the tip of the speaker cable and - on the shaft. It makes a loud WHOMP! Scary loud if you aren't expecting it.

    After they jump they hold at the 9vdc position draining your battery until it dies but you remove it just as soon as it goes WHOMP!.

    If you catch a glimpse of one not jumping properly the removing of the 9v should be just as obvious as the others settle back to 'zero'. Any that didn't jump in unison that were paired with a working one will jump less vigorously backwards when the 9v is applied as they are pulled in by the vacuum of the other one going outwards.

    This tells you very quickly if some are ruined by discontinued voice coil.

    Have a look for creased cones. Semicircular traces seen nearer the outer edge.
     
    Eedwards7891 likes this.
  10. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    Thank you! This is very descriptive . I’ll perform the test and report the results.
     
  11. You could try sitting on the cab to determine if it's a bracing issue. Your body weight on the cab will "tighten" up any loose bracing, absorbing your weight. Have a seat and play through the cab.
    Fishheadjoe
     
    Eedwards7891 likes this.
  12. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    Honestly not a bad idea!
     
  13. You should try it both upright and laying on it's side to be sure....
    Fishheadjoe
     
    Eedwards7891 likes this.
  14. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    Hey ,certainly makes sense , I’ll give it a try! Thank you for your advice !
     
    Fishheadjoe likes this.
  15. micguy

    micguy

    May 17, 2011
    I just looked at the specs on that cabinet - it says the -3dB point is 58 Hz, and the -10dB point is 40 Hz (essentially Low E on a standard tuned bass). You're asking a lot of that cabinet to go that much lower. My guess is that, whether or not a particular speaker in the cabinet has issues, the amount of excursion you're asking of the thing by pushing it that low is part of the problem, and even if you do "fix" the thing, it won't stay fixed long. Bass guitar cabinets aren't really designed to go that low. A good PA subwoofer (how big is your van?) might do that OK.

    I play 4 and 5 string basses (standard tunings on both at this point). I have a couple cabinets that I have used for some relatively low volume gigs - the only gigs I do where an amp is involved are "coffee house" kind of volumes. The cabinets are ones I designed that do better at 40 Hz than standard bass guitar cabinets - they trade off some efficiency and size to do that. I've never played my 5 strings through my cabinets - those are only used on ampless gigs, where the low end is covered by big PA's.
     
  16. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    That’s kind of my fear . I’m hoping I can fix it and find a better solution. I never expected an 810 Ampeg cab to be insufficient , lol. I know al Cisneros in sleep runs them, but they also play in C standard . A# is super low , and sometimes I question why we do it , lol. I’ve also thought about skipping the a# on the lowest string and using the F# as the lowest instead. Basically, matching the guitarists 2nd string on down .
    Thank you for your help .


    Spec wise, I’ve noticed that other speaker cabs advertise much lower frequency response , down to the 30Hz on the Hartke Hydrive 4x10. Would that even make a difference ?

    Also, if I fix this cab, could I just use an e q pedal to dial out all the lows lower than 60hz ? Would that help push the cab less?
    Thank you for your help .
     
  17. Wasnex

    Wasnex

    Dec 25, 2011

    The 810E will be fine at low volume. A bass guitar will not put out a lot of fundamental down at 29hz, but if you are really boosting the lows and cranking your amp to max power I think you could easily push your cab beyond it's limits. An HPF would be useful for protecting the speakers.

    Here's a related thread on how energy is distributed in the tone of a bass guitar note: Bass frequency/waterfall plots: what they mean to rigs

    As far as what people do. I don't think most people actually have rigs that can faithfully play flat to 29hz. They just make due with what they have. Probably the best thing is to learn the limits of you rig and do your best to stay within those limits. If you want speakers that can play high SPL to 29hz you will need a big wallet.

    Ported speakers do tend to play lower than sealed speakers. However below their intended pass band, power handling drops off super fast. Basically it's essential to run an HPF just below the tuning frequency of the port to protect the drivers from over excursion.
     
    bobyoung53 and Eedwards7891 like this.
  18. Eedwards7891

    Eedwards7891

    Dec 11, 2017
    Thank you. When you say “HPF”, does that mean high pass filter ? Also, would something similar exist to limit lows?

    would an eq with a negative decibel rating be able to cut out those super lows and super highs ?

    thank you for your help
     
  19. Wasnex

    Wasnex

    Dec 25, 2011
    Yes a HPF means high pass filter. Using subtractive EQ down low would offer some protection, but it will not be as effective as an HPF. Also, EQ will probably gut your sound a lot more as well.

    If you see a frequency response listed without a qualification like +/- 3dB, it's often the -10dB rating. I don't recommend pushing a ported speaker hard down to it's -10dB limit because the cone will be making massive excursions and not producing much sound. I believe it's fairly common to set the HPF no lower than the -6dB, but it depend upon on the cabs tuning and how hard you intend to push it.
     
    Eedwards7891 likes this.
  20. micguy

    micguy

    May 17, 2011
    The specs on the Hartke boxes are...."sparse" would be the nice word; I'd consider that 30Hz sec to be optimistic (perhaps wildly so) - they don't even give efficiency numbers on their cabinets - they only say they're "really efficient". I wouldn't trust them to do anything without trying it myself, given what I see in the manual.

    If you do get your cabinet up and running OK, protecting it is the job of a high pass filter - eq's don't generally do what you want. My guess is that, if you get a high pass filter in place that protects your cabinet sufficiently, you will find the usefulness of your lowest notes is diminished. I personally don't see the musical usefulness of playing a low B on a 5'er in a loud passage if it isn't moving a bunch of air - that's what that note is for at that point. Luckily, I play through some decent PA's. Not sure if that's the situation in your band - if it is, then high pass away, and let the PA carry the load. If not, you might revisit your tuning to something that works better.
     

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