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Does wattage always=volume?

Discussion in 'Amps and Cabs [BG]' started by Wxp4759cb, Nov 17, 2001.


  1. Wxp4759cb

    Wxp4759cb

    Nov 23, 2000
    Kansas City, MO
    People say that to run such and such cab efficiently you need such and such wattage. Is 1000 watts neccesarily louder than 500? Not can it be but is it always. I like the balance between my 15, and 10s, but can adding more wattage to the 15 make it sound better without making it louder?
     
  2. Well, I have a 12 watt amp, and a 160 watt amp, and I can't tell the difference in volume, (although the 160 has more low end)
     
  3. BigBohn

    BigBohn

    Sep 29, 2001
    WPB, Florida
    more speakers would yield more noticeable increase in volume. essentially, more wattage would give you a cleaner, non-distorted tone because more headroom. what headroom means is having a 1000 watt amp and only crankin it to a certain volume that only uses 500 watts, but still having it loud and clean, unlike crankin a 500 watt amp to 500 watts because you'll get dirty, distorted wattage at that level.
     
  4. CrawlingEye

    CrawlingEye Member

    Mar 20, 2001
    Easton, Pennsylvania
    Your volume mainly is due to the SPL of your speakers. However, on the contrary, if you compare...

    A 200 watt head plugged into a 8x10 is going to be louder than the same 200 watt head with a 4x10 cabinet, due to the greater SPL of the larger cabinet, and more speaker volume.

    I know there's people who could explain this better than me, I hope this holds you off 'til Joris, Bgavin, or one of the other gurus gets to this. :)

    Continuing on... The 200 watt head through the 8x10 (or 4x10) will be louder than an 100 watt through it.

    If you double your watts, you come out with a one db increase, from what I gather. This can easily be accomplished with more efficient speakers. However, with certain speakers (such as subs) you need a wealth of power to power them, considering the frequencies they cover don't exactly allow room for efficiency.
     
  5. Wxp4759cb

    Wxp4759cb

    Nov 23, 2000
    Kansas City, MO
    I am running a 2x10, and a 15 off of 500 watts. The 10s sound great, but I think the 15 sounded better when i was running it with a 4x10 off 700 watts. I do not want to make the 15 louder, I want it to stay the same volume. Will adding more watts make it sound better. Right now I am not turning volume up past 5 if that makes a difference.
     
  6. Adding more power will not change the tone of the 15. Unless you're driving the amp you're using now way into clipping..... Different amplifiers sound different, but this is generally independent from actual output power and more dependent on things like damping factor and slew rate. Having more power will just give you more headroom (which is a good thing, of course:D) if the levels are kept the same.

    BTW, doubling your power gives a 3 dB increase in SPL, which corresponds to a just noticeable increase in loudness.
     
  7. PollyBass

    PollyBass ******

    Jun 25, 2001
    Shreveport, LA
    to answer your qustion. No. it doesnt. But in theory, more watts, does=louder. But this is not always the case. I mean, you can tell a 1000 watt amp is louder than a 12 watt amp. but, some companys rate there wattage diffrently,...so...there you go.
     
  8. MikeyD

    MikeyD

    Sep 9, 2000
    Hi, Space! I have to take issue with this. The smallest increment generally audible to human ears is 1 dB. It is certainly a very subtle change in loudness, but it is perceptible. 3 dB is a noticeable increment in loudness, but audiologists consider a doubling of loudness requires about a 10 dB increase in SPL (as you know; I'm just posting for others' edification). Another way to look at it: the vast ocean of loudness between 0 dB (the threshold of hearing) and 120 dB (the threshold of pain) means 120 increments of 1 dB. I bet I can hear 120 gradations in intensity between these two dynamic extremes. Whatchoo think?
    - Mike
     
  9. RebelX

    RebelX Guest

    Oct 27, 2001
    Merrimack, NH
    I have to agree with MikeyD on this one, except that I believe I can percieve somewhere between 1.5 to 2 DBs of change on full out music. Different ears, that's all.

    It's funny how debates come up on wattage, especially when people are looking at similarly rated gear. Let's take two bass amps, one rated at 250 watts and the other rated at 300 watts. For this argument let's also say that they come from the same manufacturer, and were tested by the same equipment on the same day and that all other components (bass, player, cab, etc) are equal. People jump all over the marketing bandwagon for the more powerful amp. In reality, you're gaining an additional 20% of power with the larger amp. Since it takes twice the power to get another 3 Db's you end up gaining somewhere around .6Db's. In otherwords, not a lot more volume. This is why there is always a different feature set on the more powerful amp. If two people put the two amps side by side, they probably wouldn't be able to tell the difference and they wouldn't sell the "bigger" more expensive amp.

    This is one reason why the effeciency rating on different cabs comes into play. Take two cabs, let's say the Eden 410XLT (106Db rating) and the Acme B4 (96Db). I know that these two are very different cabs, but lets go with it. There is a 10DB difference in the measurement, theoretically this means you would need somewhere around 3 times the power to equal this in perceived volume. That's why everyone says the Acme's are power hungry. They made tradeoffs to reach those extreme low notes cleanly and accurately. Primarily effeciency.

    Now, with that said, the bottom line is that many things work together to bring you a "louder" sound, the amp, the cab, the speaker effeciency, the speaker itself, the number of speakers, how you EQ the thing, blah, blah, blah. Buy what sounds good and what gives you enough volume in your situation to keep up. I've always followed my own rule of "7". If I need my master volume to go over 7 (on a scale of 1 to 10) on a regular basis, I need to take a look at my rig. Maybe a little more mid to cut through, maybe a different cab, maybe more power. Once I reach that magical "7" point. It's back to the drawing board, but the drawing board doesn't necessarily mean spending more money.

    Also, remember that ``In theory, practice and theory are the same, but in practice they are different.'' Larry McVoy

    Keep it low,

    Rebel X
     
  10. RebelX

    RebelX Guest

    Oct 27, 2001
    Merrimack, NH
    :eek: Something about my last post just didn't seem right. I was using linear math to discuss a logarithmic equation. Db's are not linear. I'll re-work some math tomorrow when my heads on a little straighter and get back to you folks with a more correct answer. Sorry for the misinformation (I believe it's misinformation anyway).

    Maybe someone else will bail me out of this mess beofre I get back to it tomorrow. :)

    Thanks for being patient.

    Rebel X
     
  11. Hey guys,
    You'll note that I didn't say that 3dB is the smallest increment humans can distinguish:D. I am generally in agreement with you (Mike, RebelX). I tend to say "just noticeable" because I want people to understand that doubling power doesn't make a huge difference in SPL. I have my hearing tested fairly frequently (My aunt's an audiologist at the School for the Deaf) and I can hear 1dB increments for frequencies above about 100Hz and below about 16kHz. Outside this range my resolution isn't as good. I have a small deficiency between 2k and 5k, but it's only slight. No doubt due to years of loud music... I'm very careful these days. I wear earplugs at any show that I'm not actually mixing, even if the SPL isn't really high, and I wear earplugs when I'm playing with the loud band (cymbals just kill me). I think people involved in music tend to have better resolution and better sense of tone than the general public, and part of it is that musicians' ears have been trained to pick up subtleties of music and by extension frequency and SPL.....The musicians who are listening, anyway. (Some aren't but I won't get into that:D).
    RebelX, I totally agree with what you said about wattage and why debates arise. I'm too tired to check your math, sorry;)
     
  12. MikeyD

    MikeyD

    Sep 9, 2000
    Yeah... if cabinet A measures 96 dB SPL sensitivity, and cabinet B measures 106 dB - and assuming the measurements were made exactly the same way with the same wattage input at the same frequency - then cabinet A would need 10 times the power to achieve the same loudness as cabinet B. Power ratios and SPL are calculated with 10*log(P/Pref).
    - Mike
     
  13. EString

    EString

    Nov 20, 2000
    Los Altos, CA
    This question isn't even worth asking. Sure, there might be a "theoretical" answer, but so many variables affect perceived volume in the real world that any conclusions drawn would be rendered useless.

    If you are really that concerned about sqeezing out every fraction of a decibel you can get, you would do best consulting an acoustics laboratory.
     
  14. I'm gonna tell you guys again, the setting of the master volume knob has literally NOTHING to do with how many watts come out! It's not like "1 out of 10" means "10% of the power" and "7 out of 10" means "70%, so you would have some 30% headroom left"

    Let me take my own amp as an example. Which, BTW doesn't even have a 0-10 scale, but a "-infinite dB to 0 dB" range. Anyway, when I set my preamp to -20 dB output level I can set my amp to 0dB (10 out of 10) and hardly get any sound. When I put the preamp to +4 dB and turn down amp to -10 dB (7 out of 10), I'll blow out the windows.

    When I turn down the midrange on my bass, chances are I have to crank the amp to 10 out of 10 again, to hear myself.

    You said yourself, that so many factors influence amp power, but yet you don't seem to understand volume knobs. :confused:
     
  15. RebelX

    RebelX Guest

    Oct 27, 2001
    Merrimack, NH

    Sorry for some confusion. Let me layout how my amps and preamp generally are set.

    Gain. Set to point just below peak lights for normal passages, peak light flashes during peaks (+10db). Sounds normal.

    EQ Settings - Adjusted to taste.

    Master Volume - Whereever I need it for that day.

    Power Amps - Full on, all the time. No sense in choking the volume at the last stage.


    Given this setup. The only part I adjust to increase the amount of signal I send to the power amps is the master volume. Watching the meters on both my preamp and power amp I can kind of tell when I'm pushing the most power out. You are absolutley right that if I were to drop the gain down on the front end, I could crank the pre up to 10 all day long and wonder why no one can hear me. I could do the same on my power amp by not setting the thing on full on all the time. I could and should have been clearer on my explanation.

    Mike - Thanks for the math bail out. After I left my computer, I started thinking. Wait a minute, that's not right.

    Rebel X
     
  16. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    "Choking the volume?"

    For best results, use only as much power amp gain as you need. That's why they have knobs. Turn the amp down and hit it with a hotter signal, and you'll get a better signal-to-noise ratio, as long as you don't drive any upstream devices into clipping.

    -Bob
     
  17. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Bravo, Joris!
     
  18. PollyBass

    PollyBass ******

    Jun 25, 2001
    Shreveport, LA
    Go joris!, Go joris!, Go joris!.........
     
  19. RebelX

    RebelX Guest

    Oct 27, 2001
    Merrimack, NH
    I'm curious. Everything I've always read and been told on power amps was to leave them at wide open whenever possible. This was to provide the greatest sensitivity to the signal and to provide the most headroom. I even tracked down the original manual for the amp and it stated the same thing.

    I understand the value of being able to adjust the levels on the power amps, especially with preamps that sound "better" when you run them hot, I've just never had the need to use anything other that the master volume to adjust the overall level. I've never noticed a real difference in sound with either my Grand Prix or my old Trace Elliot when using the master volume for that purpose. I definitely noticed differences when playing with the input gain though.

    I guess that in the end there is lot's o' ways to make it work. This method has worked for me for a bunch of years and has always proved reliable for me.

    Rebel X
     
  20. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    One thing about audio: there are a lot of falsehoods floating around. Ask 10 people at a music store what damping factor or slew rate means and you'll probably get at least six different answers, and maybe one of them will be right.

    Turning an amp up to full gain will give the greatest sensitivity to the signal and to all the hum and noise, too. And to compensate you'll have to turn the preamp down, which brings the signal down closer to the noise floor to boot. This will also increase the headroom in the preamp but decrease it in the power amp. And like I said, it'll degrade your signal-to-noise ratio due to the double whammy of weak preamp signal + lots of gain at the end.

    The remedy is simple: get your gain up early in the signal chain (that is, in the preamp, especially in the input gain), keep a healthy level through the EQ and processing circuitry, and trim the power amp gain control down.