How much speaker do you really need?

Discussion in 'Amp Central Station' started by Milspec, Oct 7, 2018.

  1. Milspec

    Milspec Friend of Leo's

    Feb 15, 2016
    This question has always confused me in reference to the power rating of the speakers needed for the particular amplifier. I was told early on that you should go with speakers equal to twice the rating of the amp output, but that seems like a very generic answer.

    I am teasing myself over testing out different speakers for my recent purchase ('79 Twin) which is rated at 135 watts. The speakers in there now are rated for like 300 watts, but what options do I really have here? I am a big fan of WGS speakers (ET-65 and 12C), but they would not measure up on paper to handling this amp.

    Obviously, I am not going to dime this amp in my lifetime unless I am looking to attract a rescue helicopter, so how much power handling would I really need to handle to reach say mid-dial on the volume knob?
    viccortes285 likes this.

    LOSTVENTURE Tele-Afflicted

    Feb 13, 2007
    Charlotte, NC
    Nothing below a 200 watt rating would be safe. I say that because a 135 watt Twin can actually peak above that without dimming the amp.
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  3. printer2

    printer2 Poster Extraordinaire

    May 24, 2010
    Really depends on how you use the amp. If you had a speaker on par with the ET-65 and don't produce a continuous fuz then they might hang in there.
    zephyrR1 likes this.
  4. bftfender

    bftfender Friend of Leo's

    Dec 21, 2017
    York PA
    WGS make the Liberator a higher power handling will handle that amp
    Milspec likes this.
  5. Old Tele man

    Old Tele man Friend of Leo's

    May 10, 2017
    Tucson, AZ
    RULE-of-THUMB: SPEAKER(s) rating at least TWICE the AMP output.
    Milspec likes this.
  6. bftfender

    bftfender Friend of Leo's

    Dec 21, 2017
    York PA
    just thought Emi Swamp Things..are great in that amp and are 150 watts//pair of them are very good in fender amps.
    Wally and JustABluesGuy like this.
  7. JustABluesGuy

    JustABluesGuy Friend of Leo's

    Sep 2, 2016
    Houston, TX
    The double the amp recommendation is a good guidline for speaker safely because (as has been mentioned) amps can have transient peak output much higher than their rating. Using heavy distortion (even at lower volumes) can damage them by attempting to produce semi-square waveforms that cause extreme cone excursion.

    If you play clean at low volume, you might be ok. But if you have musician friends like mine, one of them will dime it and hit the fuzz and blow them instantly.
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  8. Milspec

    Milspec Friend of Leo's

    Feb 15, 2016
    I have a couple of Altec-Lansing 417-8C speakers (one in a 1x12 cab and the other shoved into a Blues Jr) that I might extract and try out in this amp. I think they are 100w each RMS, but that might not be the right direction due to weight.
  9. Milspec

    Milspec Friend of Leo's

    Feb 15, 2016
    Sadly, I have several friends like you describe.
    telemnemonics and JustABluesGuy like this.
  10. bftfender

    bftfender Friend of Leo's

    Dec 21, 2017
    York PA
    this is amusing me. we are metal guys killing our speakers we dont have double up
  11. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Mar 2, 2003
    Lawndale CA
    It's actually more of a voice coil heat problem.

    If you take a single-frequency distorted waveform and flatten it out, and a clean waveform and flatten it out, the distorted wave will be FAR longer.

    This is a VERY simplified description meant primarily to form a mental picture - distortion needs more power handling.

    To be realistic, a 135 watt Twin - unless used outside with no mic'ing in a canyon - won't be putting out more than 15-20 watts at "normal" volume levels.

    But....If you DO play loud and/or DO use distortion, you should figure a safety factor.

    The late Ted Weber recommended double the amp's rated RMS output (assuming fairly new speakers - they lose power handling as they age) for clean and mid-volume, mild overdriven tones. If fairly high distortion is used - 3x; metal 3-4x.

    If you play at high volume and/or with a lot of distortion or fuzz it's a guessing game - so guess on the safe side.
  12. telemnemonics

    telemnemonics Doctor of Teleocity

    Mar 2, 2010
    Unless they are recent high quality recones I would not assume they are 100w speakers or even turn up that Twin through them.

    IMO a pair of good Altec 417s is more valuable than a 135w Twin!

    If you run the Twin at lowish volume the Altecs might improve it though.

    Maybe if you have a 15-20w amp you could turn that up to full volume into one altec (or one speaker you have a pair of) and run the Twin into the identical speaker until it's similar volume to the 15-20w amp.
    That's pretty loud and you can then note the vol knob position on the Twin and keep it there or below when using under rated speakers.

    I've run numerous 100w Marshalls at full volume but kept my 135w Twin and also my 135w Bassman 135 below full volume, because they are just so damn strident and harsh on the ears.

    If you plan to gig with no PA in a Texas roadhouse with monster trucks clashing in the parking lot, buy some damn speakers that are suitable!
    JustABluesGuy and Milspec like this.
  13. jsnwhite619

    jsnwhite619 Friend of Leo's Ad Free Member

    Sep 10, 2013
    At the risk of going off the rails here, but still similar because it comes down to output power and requirements, I have to ask about this. In a recent thread, I talked about using a dB meter and estimating output power using the speaker specs and the spl being produced - how many watts are required to make this level with this speaker. The math worked on the calculator with both amps that I tried. They came out to clean output that was the amp's rated output, and overdrive levels that were slightly higher -- 2-3dB more when dimed and overdriven. The thread is here.

    Here was your first response - "No. Honestly, it was a coincidence. There is NO relationship between volume and output power; even less between either volume or power and control settings and the thought that changing pitch could raise the DB level (or output power) is, well, ridiculous. You stumbled onto a completely random situation that simply happened to look right. Sorry."

    So, for you to say that everything that I found was pure coincidence with no relationship between output volume and power, how do you determine that a Twin at "normal" volume will only be putting out 15-20 watts? You said there is NO correlation.
    viccortes285 likes this.
  14. GuitarJonz

    GuitarJonz Poster Extraordinaire

    Mar 16, 2003
    Doesn't Warehouse also make an ET-90?
  15. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Mar 2, 2003
    Lawndale CA
    Thanks - and good question. The two threads were very different, and my comments were relevant to the context of each

    In this thread I'm talking about VERY rough numbers and ONE amplifier. I should have been more specific in describing my use of the term "Normal volume" for that specific amp. Run at a reasonable club volume it will put out a fraction of maximum output power.

    I could have just as easily said 5-10 watts and been accurate depending on the situation - but it would have been splitting hairs, and the point is the same. It will also be true of any tube amp - at low to mid volume they put out a fraction of the maximum rated output power.

    The other post was in a thread discussing deriving specific output power from DB meter results - and the two threads are not remotely related.

    You were hoping that informal results you obtained were correct and be consistent; it was explained that it was coincidental and several members posted reasons why.

    To bring it back in context here - the fact that amps put out a small fraction of power at lower volume is true of ALL amps. And it's unrelated to trying to directly relate specific spl readings to exact output power numbers.

    I hope that clarifies it. If not, please PM so we don't distract from this thread.
  16. sliberty

    sliberty Tele-Afflicted

    Mar 19, 2007
    East Brunswick, NJ
    As a kid, I owned a HiWatt Custom 100, a Marshall 4x12 (100 watt capacity), and an MXR Dist+. I used to dime the amp (no wonder I can’t hear anything anymore), and it glorious. But it only took me 4 days to blow 3 of the speakers in my cabinet. Since then, my policy is to go with speakers that can handle twice the wattage of my amp. I don’t care if it is overkill in some situations. I have real world experience that guides me.
    Milspec likes this.
  17. Axis29

    Axis29 Poster Extraordinaire Ad Free Member

    Jan 2, 2007
    La Quinta, CA
    I had a Vibrolux Reverb that had a pair of server P10Q’s in it. I believe they were 25 watt speakers. They sounded great and did fine for me and the previous owner for a number of years.

    An online acquaintance mentioned he had never played through a VR and could he drop by and try mine. Of course I agreed... I turned my back for a second and he dimed it. I didn’t think about it until a few weeks later when I was trying to chase down what I thought was a bad tube... nope, both speakers blown.

    Since then, I am pretty careful about speaker ratings in my amps. Although, the refined Weber’s are now in my ‘63 Vibroverb Ri, which actually has a few more watts than the VR did. I’ll be very careful letting anyone else play through it.
  18. codamedia

    codamedia Friend of Leo's

    Apr 4, 2009
    Western Canada
    Many speakers can handle clean power far beyond it's rating. With PA and Monitor cabinets the rule of thumb is 2.5 times the power in relation to the speaker rating. For example, an 800 watt power amp is not uncommon on a 250 watt speaker and both live comfortably for many years. BUT - if you put a 200 watt power amp on that same speaker, it is almost certain death the moment the power clips!

    Guitar players and their usage of gear is different.... we look for dirt, we want it to clip, we want overdrive and distortion. Since we are feeding speakers dirty signals, we really are safer to use over rated speakers in our amps.

    There is nothing wrong with running a lower rated speaker in a higher powered guitar amp, just don't expect to crank the guitar amp without consequences ;)
    Last edited: Oct 12, 2018
    Axis29 likes this.
  19. BobbyZ

    BobbyZ Doctor of Teleocity

    Jan 12, 2011
    Snellman MN
    The standard and even some of upgrade speakers used in Twin Reverbs, blackface to silverface were never up to the task of handling them fully cranked.
    We still see Twin Reverbs with original speakers, simply because most people didn't crank them up that far or for very long.
    Personally I don't worry about having much extra wattage capacity in my TRs. In my smaller amps, that I might actually get running close to the rated watts are a different matter. But most of those aren't at the "double wattage" figure. (actually I think just the DR is, with its 65 watt Maverick)
    It's a matter of volume, very few of us can even crank a 22 watt Deluxe Reverb, full up anywhere.
    So if you're not Santana, Jerry Garcia or Uncle Ted, you're probably OK at around 100 watts capacity, probably even less.
    But you know how loud you can play, I don't! Does blood come out of your ears when you play? It would if you crank a ULTR. :)
    telemnemonics and Milspec like this.
  20. Norris Vulcan

    Norris Vulcan Tele-Meister

    While good sense would have me agree with "twice the amp power" rating, the AC 30 uses two Celestion Blues rated at 15w.
    Milspec and BobbyZ like this.
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