What is it that I'm doing to mess up the speaker?

Discussion in 'Amps and Cabs [BG]' started by joemamma, Aug 26, 2004.

  1. joemamma


    Jul 18, 2002
    I have a 2 year old Peavey MicroBass and the speaker has blown twice. I never turn the gain beyond 4 and the other settings are low also. What could I be doing that causes the speaker to go once a year. This last one cost me $50.00 cause the speaker warrenty is only good for a year. Are the MicroBass speakers crap? and is there a better speaker to get next time?

  2. DubDubs


    Aug 23, 2004
    Los Angeles
    You could be turning the volume too low? Just yesterday I was educated on the fact that it's very possible to damage a speker by not putting enough power into it. What's the output of the amp, and what's the power rating on the cab?
  3. ihixulu

    ihixulu Supporting Member

    Mar 31, 2000
    getting warmer
    Dubdubs, the term underpowering a speaker is actually a misnomer; the only way to really blow a speaker is to overpower it. It just so happens that if you have an amp of low wattage, the tendency is to push it too far into clipping which causes it to create a lot more power thereby blowing the speaker. So in a roundabout sort of way, not having enough watts CAN cause you to overpower your speaker.

    However, if the volume is low, the only things I can think of is that there is too much bass hitting that speaker (it's an 8" right?) or there is something wrong with the amp.
  4. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA

    Yep, what ihixulu said. You can not damage a speaker by underpowering it. The only way to kill it is by pumping too much power through it.

    My first thought would be, nix the stock speaker and get a "good" speaker instead. My best results over the years have been with EV speakers (for bass). If you can find an EV with the same size and ohms, and a slightly higher power rating, go for it. Chances are the stock speaker is inadequately spec'd, and operating on the hairy edge of self destruction. That would be "not at all surprising", it's very common in the world of combo amps.

    As a first guess, I'd take the amp's maximum rated RMS power, and triple it. (Actually it would be 2.8 times, but triple is close enough). That'll be a reasonable approximation to the peak power output under real conditions. Get a speaker that's rated for at least that wattage. And make "sure" it's the same ohms as the stock speaker.
  5. Joemama--I'm no amp tech, but as I understand it speaker damage results from a variety of things including 1)too much power, which moves the speaker beyond it's range of movement and 2) sending clipped signals to it which create very abrupt speaker movement and leads to tears in the speaker.

    I own a microbass amp and use it for teaching and have played it occasionally on a very quiet gig. From what I know about this amp, the power section of the amp is always turned all the way up and volume is changed by adjusting the input gain. This type of configuration typcally doesn't produce a clipped signal from the power amp section so if you're not running the thing wide open all the time I would suspect that something is not operating correctly within the amp.

    How do you use your amp--are you driving it hard? Have you spoken to Peavey about this?
  6. joemamma


    Jul 18, 2002
    Thanks all, for the great info. The Microbass has an 8" speaker, 8.94 V RMS, 4 Ohms and its 20 watts. The Techs at the authorized repair place who have worked on it, have never found anything wrong except the speaker. In fact this last time the tech call, he said there was nothing wrong. I told him it had distortion thru the speaker like it did the year before (I found they dont listen to them when they diagnose). I never drive the amp hard because the guys I'm playing with are all acoustic and I can over power them easliy on the low gain. I havnt spoken to Peavey's techs yet. It seems some of the most knowlegable people on music equipment are in these forums. Also, being musicians you all have more hands on then tech reps. Does switching the amp off-on hurt it? I usually turn it off before plugging- unplugging the audio cable. If the speaker goes again I'll try a better speaker. Has this happened to anyone else with a Microbass?. Thanks again guys for all the great advice.

  7. embellisher

    embellisher Holy Ghost filled Bass Player Staff Member Supporting Member

    Are you cranking the lows on the amp?
  8. xyllion

    xyllion Commercial User

    Jan 14, 2003
    San Jose, CA, USA
    Owner, Looperlative Audio Products
    Clipping will depend on how hot of a signal he is putting out of his bass as well. You may only have the knob on 4, but if your bass is active and putting out a strong signal, you can still cause distortion. The position of the knob really doesn't tell you how much power you are putting out.
  9. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Option (1) is called "excessive excursion", and results from too much "peak" power.

    Option (2) is not an accurate scenario. High frequency signals that don't result in cone movement, result in heat instead. Too much heat will fry your speaker coil (but won't generally tear the cone). This scenario is still a version of "too much power", but it's "average" power, so instead of excursion, heat is the culprit. This isn't the speaker's fault, it's the amp's fault.
  10. joemamma


    Jul 18, 2002
    I usually dont go over 5 (or half way) on the low and the bass is passive
  11. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    I'd recommend an Eminence Beta 8" speaker available online through www.partsexpress.com. Quite a bit more robust than the original replacement. Just be careful not to push the little amp too hard. Level "4" might be too much for it if you are trying to pump a lot of low end through it.

    I'd also recommend finding a larger used amp if you're having such troubles. But if you want to keep the Microbass, the Eminence Beta 8 is a good way to go.
  12. Petebass


    Dec 22, 2002
    QLD Australia
    Well now I'm stumped. I read all these posts and the whole time I was thinking "he needs a louder amp, he's asking too much from it". Then you posted this and I'm back to square 1.

    Has the amp been modified in any way?
  13. Yossarian


    Jun 24, 2004
    We are talking about the little combo practice amp type thing, right?

    Assuming that is so, I think it'd have to be something else, like... I dont know, sketchy wiring where you play it alot? power surge type things? Could your instrument cable be screwed up (I doubt that could have any effect but i dont know) it's just, I have a peavey microbass, have had it for four years, and I have asked WAAY too much from it, I've played it turned all the way up, with all the EQs up struggling to be heard in a punk band in my early days (multiple times, 40 or so minutes at a time) that's playing with a pick, I haven't taken care of it in any remote sense, and it's in perfect condition. I swear this thing is invincible under regular circumstances.

    Out of curiosity, is your model made in the USA or in China? I heard someone complaining about the China made model a while back on here. They were just talking about the sound I think, but who knows.
  14. joemamma


    Jul 18, 2002
    Hey all,
    Havnt modified the amp at all. This is the 20 watt Peavey Microbass practice amp. Instument cable is 2 yrs old. The other I have is less than a year. I did look on the back yesterday and it's from............CHINA!!!! I read the same thread about the sound on the chinese amps, but this one has always sounded great. I know some of you have used these amps to kick field goals with and they still sound great. I baby this one and the speaker has taken a dump twice, almost exactly a year apart (these are 2 different speakers). I would go with a bigger amp but this thing is so light and compact and more than what I need. My house is 1963 and has no ground, wonder if that does anything. I do get a bit of a hum if I turn up the high and mid that I don't get playing at a building that has a ground.

  15. Yossarian


    Jun 24, 2004
    I wouldnt be surprised if it has something to do with the wiring in your house. Maybe (assuming you dont) you should start plugging your amp in through some kind of snazzy surge protector.

    Or the obvious solution: buy a new house for the sole purpose of playing bass in it. :bassist:

  16. Yes...and in MHO and experience the latter (heat/fried voice coil is usually the scenario for a damaged speaker.) The term 'blown' has become synonymous with a damaged speaker...I don't know, I've generally considered a 'blown' speaker to mean over-excursion, at any rate... I've found having at least double the power vs. rated power for the cab/speaker has alleviated the heat issue...however, one has to take into account that you don't run 2400 wide open into 200w speaker cabinet....or...well...the obvious will happen. I've come to really appreciate the speed with which the speaker will fire and recover with the added headroom.