Harmony Central Forums
Announcement Announcement Module
Collapse

Announcement

Harmony Central has “soft launched” our new mobile experience this past week. While we have done extensive testing, we know that with a community as large as HC that there will be items that surface that will still need to be addressed. We are asking that you utilize the thread belowto report any challenges you may encounter. Here are the things we request you provide: A brief description of the issue, the device and operating system version you were using, the browser and version, screen resolution, and a screen shot of the display.
Thanks for your patience as we work towards the best experience we can provide to our community.

http://www.harmonycentral.com/forum/...ablet-feedback
See more
See less

How "loud" is that amp?

Page Title Module
Move Remove Collapse









X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • How "loud" is that amp?

    Since it seems to come up fairly often, I thought I'd do an article on it for this week's HC Confidential Newsletter. In case anyone's interested, here's the link:

    http://www.harmonycentral.com/docs/DOC-1951
    **********

    "Look at it this way: think of how stupid the average person is, and then realize half of 'em are stupider than that."

    - George Carlin

    "It shouldn't be expected that people are necessarily doing what they appear to be doing on records."

    - Sir George Martin, All You Need Is Ears

    "The music business will be revitalized by musicians, not the labels or Live Nation. When the musicians decide to put music first, instead of money, the public will flock to the fruits and the scene will be healthy again."

    - Bob Lefsetz, The Lefsetz Letter

  • #2
    A good read...nice job glossing over the physics without getting to crazy.

    Comment


    • #3
      Thanks... I could have gone into a lot more depth and detail in terms of the "math", but like I said, I don't want to see eyes glazing over... if I can simplify it for the regular Joe; forgo formulas and make it fairly understandable in terms of the basic "concepts", then maybe it would be more helpful to a larger amount of guitarists. That was the intention anyway...

      Thanks for reading it.
      **********

      "Look at it this way: think of how stupid the average person is, and then realize half of 'em are stupider than that."

      - George Carlin

      "It shouldn't be expected that people are necessarily doing what they appear to be doing on records."

      - Sir George Martin, All You Need Is Ears

      "The music business will be revitalized by musicians, not the labels or Live Nation. When the musicians decide to put music first, instead of money, the public will flock to the fruits and the scene will be healthy again."

      - Bob Lefsetz, The Lefsetz Letter

      Comment


      • #4
        Today, I learned...

        <div class="signaturecontainer"><font size="1"><a href="http://acapella.harmony-central.com/showthread.php?2014628-Official-Effects-Good-Deal-Bad-Deal-Sticky!&amp;p=42393951&amp;viewfull=1#post42393951 " target="_blank">Good deals</a><br />
        <a href="http://www.facebook.com/maxharlan" target="_blank">Facebook</a><br />
        <a href="http://www.last.fm/user/MadMax808" target="_blank">Last.fm</a><br />
        </font></div>

        Comment


        • #5
          are less efficient speakers more desirable for guitarists? what are the cons of a more efficient speaker? iow, why don't the amp builders use these in the first place?

          Comment


          • #6
            are less efficient speakers more desirable for guitarists? what are the cons of a more efficient speaker? iow, why don't the amp builders use these in the first place?


            Same reason they use junk parts everywhere else on amps--to cut costs.
            <div class="signaturecontainer"><font face="Arial Black"><a href="http://www.facebook.com/thatandthevatican" target="_blank">THAT AND THE VATICAN (MY BAND)</a></font></div>

            Comment


            • #7
              The thing that always gets me is how anyone can determine what is twice is loud. I mean really, how do you know? Sure, one amp will be louder than another, but it seems like it's almost impossible to judge what is actually twice is loud, without having an SPL meter on hand.

              Comment


              • #8
                great read

                Comment


                • #9
                  are less efficient speakers more desirable for guitarists? what are the cons of a more efficient speaker? iow, why don't the amp builders use these in the first place?


                  Excellent questions!

                  Originally, less efficient speakers with relatively low power handling capability were utilized in guitar amps because that was all that was readily available. Over time, more efficient designs were made; speakers with higher sensitivity, greater power handling capacity, and wider frequency response... but they tend to cost and weigh more. Also, tonal considerations come into the equation. A more efficient speaker may - or may not - be to your liking. Guitarists are fairly finicky and conservative traditionalists in terms of their gear. AlNiCo speakers (that utilize AlNiCo magnets) are still favored by some, even though rare earth magnet materials (neodymium, samarium cobalt, etc.) are stronger and more efficient. Ceramic magnets are often utilized because of their relatively low cost... it's always a trade off in terms of weight, cost and performance... and sound.

                  Remember, "speaker breakup" and other tonal contributions from the speaker may be considered beneficial, even though they are the antithesis of "accurate". The E/V 12F (a 12L variant made for Fender) in my Princeton Reverb II has 200W RMS power handling capability, is highly efficient and loud as hell (~101 - 103 dB @ 1W / 1m), but it doesn't even began to strain or break up under the influence of that little 20-22W amp. It has a huge, open and big bottomed sound to it, and sounds completely different than the 15W Weber Blue Dog in my AC15, which not only has different frequency response characteristics, but also strains and distorts when pushed. It's not "better" (except in terms of power handling capacity and efficiency) or worse, just "different".

                  Sometimes we guitarists want that tonal contribution from the speaker. A Celestion Greenback breaking up has a distinctive sound to it, and it contributes positively to the sound of a wide open Marshall. A Blue is closely associated with the classic "Vox sound", just as the old Fender Jensens are the voice of old Blackface amps. Also, wide range frequency response is not always desirable in a guitar amp and speaker. We LIKE that bandpassed sound, with nothing much going on above 5-6kHz or so... run a guitar direct into a mixing board, and you hear all that high end (stuff above 6kHz) that guitar speakers naturally roll off. Bass players love it, as do keyboardists, but guitarists? We WANT low-fidelity. That's why you'll find crossovers and multiple drivers (including horns) in keyboard and bass amps, but almost never in an electric guitar amp.
                  **********

                  "Look at it this way: think of how stupid the average person is, and then realize half of 'em are stupider than that."

                  - George Carlin

                  "It shouldn't be expected that people are necessarily doing what they appear to be doing on records."

                  - Sir George Martin, All You Need Is Ears

                  "The music business will be revitalized by musicians, not the labels or Live Nation. When the musicians decide to put music first, instead of money, the public will flock to the fruits and the scene will be healthy again."

                  - Bob Lefsetz, The Lefsetz Letter

                  Comment


                  • #10
                    Nice article Phil! Now someone needs to develop an iphone app that tells you what cab ohm's work with your head, and vice versa... that I could use.

                    Comment


                    • #11
                      great read phil!!!

                      couple questions
                      First:
                      With a Peavey Classic 50, is 50W the TOTAL output of the amp? Does that mean that if i get speakers that are rated around 25w each they will "break up" sooner than speakers at say 60W each? If i went under 25W speakers would they blow? If i got 300W speakers would they move at all?


                      Second:
                      Here is info from Warehouse 12" Veteran 30 - 60 watts :

                      Thielle-Small Parameters

                      Resonant Frequency (Fs) 102 Hz
                      DC Resistance (Re) 12.70 Ohm
                      Coil Inductance (Le) 0.59 mH
                      Mechanical Q (Qms) 12.00
                      Electromagnetic Q (Qes) 0.94
                      Total Q (Qts) 0.88
                      Compliance Equivalent Volume (Vas) 1.28 cu ft
                      Mechanical Compliance of Suspension (Cms) 0.09 mm/N
                      BL Product (BL) 15.23 T-M
                      Diaphragm Mass Inc. Airload (Mms) 26.84 grams
                      Surface Area of Cone (Sd) 53.24 cu cm
                      Sound Pressure Level (spl) 98 db

                      Is the spekaer sensitivity 98dB @ 1W / 1m?

                      Thanks
                      Mac
                      <div class="signaturecontainer"><a href="http://www.supermassivemusic.com" target="_blank">www.supermassivemusic.com</a><br />
                      <br />
                      <br />
                      <div class="bbcode_container">
                      <div class="bbcode_quote">
                      <div class="quote_container">
                      <div class="bbcode_quote_container"></div>

                      <div class="bbcode_postedby">
                      <img src="images/misc/quote_icon.png" alt="Quote" /> Originally Posted by <strong>victorwan</strong>
                      <a href="showthread.php?p=42267291#post42267291" rel="nofollow"><img class="inlineimg" src="images/buttons/viewpost-right.png" alt="View Post" /></a>
                      </div>
                      <div class="message">New Music Guru have introduce a new generation music. They have no any kind of idea from the play music and song. Then, Music Guru gate new idea and come remix, DJ Music and other composer tools. They introduce old song and music into to new song and music.</div>

                      </div>
                      </div>
                      </div> </div>

                      Comment


                      • #12
                        are less efficient speakers more desirable for guitarists? what are the cons of a more efficient speaker? iow, why don't the amp builders use these in the first place?


                        It depends on what you're going for. Speaker efficiency is only part of the equation.

                        The old Jensen speakers that came stock in vintage Fender amps often had efficiency ratings of around 93ish dB (1W/1m), while the Celestion Blues in Vox amps have always had a high efficiency rating of 100dB (1W/1m). Most stock speakers these days have sensitivity ratings that fall somewhere in between those, with 98dB (1W/1m) seeming to be the average in my experience.

                        Comment


                        • #13
                          The thing that always gets me is how anyone can determine what is twice is loud. I mean really, how do you know? Sure, one amp will be louder than another, but it seems like it's almost impossible to judge what is actually twice is loud, without having an SPL meter on hand.


                          I believe I used the term "typical listener" in the article. As with many aspects of audiology and psychoacoustics, individual perceptions and capabilities vary, but on average, most people experience and perceive a 10dB increase in sound pressure level as a "doubling" of volume. Some people are more sensitive and will hear things a bit differently, just as some people can readily pick out a change of .1 dB in a mix at certain frequencies while others can't tell when such a small change is made. And yes, this stuff is frequency dependent too... you can read up on the "Fletcher Munson Curve" or "equal loudness contours" if you'd like a more in depth explanation, but the short version is that our ears are not linear in terms of their response at various frequencies and at different sound pressure levels - our hearing is most sensitive in the midrange bands; especially at low volume levels. As levels increase, the frequency response of our ears becomes "flatter".

                          Using a SPL meter for accurate measurements is a good idea, and I have one sitting on my mixing console (and one in my iPhone) at all times. Human hearing is adaptive. We tend to adapt to changes in volume levels and baseline timbres fairly readily; which means referring to a standard reference (such as a CD you know well to reference timbre, or a SPL meter in terms of "volume levels") is a good practice to get into IMO.
                          **********

                          "Look at it this way: think of how stupid the average person is, and then realize half of 'em are stupider than that."

                          - George Carlin

                          "It shouldn't be expected that people are necessarily doing what they appear to be doing on records."

                          - Sir George Martin, All You Need Is Ears

                          "The music business will be revitalized by musicians, not the labels or Live Nation. When the musicians decide to put music first, instead of money, the public will flock to the fruits and the scene will be healthy again."

                          - Bob Lefsetz, The Lefsetz Letter

                          Comment


                          • #14

                            Remember, "speaker breakup" and other tonal contributions from the speaker may be considered beneficial, even though they are the antithesis of "accurate".


                            does kind of bring up the old "@ what THD" part of the equation. I think it was motion sound that had that electric-guit combo and the complimentary acoustic combo -- one was listed at 80 watts, the other at 100 or 110 or something -- the difference was the THD at which each was measured..IIRC it was the same power amp sectioon

                            Comment


                            • #15
                              I believe I used the term "typical listener" in the article. As with many aspects of audiology and psychoacoustics, individual perceptions and capabilities vary, but on average, most people experience and perceive a 10dB increase in sound pressure level as a "doubling" of volume. Some people are more sensitive and will hear things a bit differently, just as some people can readily pick out a change of .1 dB in a mix at certain frequencies while others can't tell when such a small change is made. And yes, this stuff is frequency dependent too... you can read up on the "Fletcher Munson Curve" or "equal loudness contours" if you'd like a more in depth explanation, but the short version is that our ears are not linear in terms of their response at various frequencies and at different sound pressure levels - our hearing is most sensitive in the midrange bands; especially at low volume levels. As levels increase, the frequency response of our ears becomes "flatter".

                              Using a SPL meter for accurate measurements is a good idea, and I have one sitting on my mixing console (and one in my iPhone) at all times. Human hearing is adaptive. We tend to adapt to changes in volume levels and baseline timbres fairly readily; which means referring to a standard reference (such as a CD you know well to reference timbre, or a SPL meter in terms of "volume levels") is a good practice to get into IMO.


                              Thanks Phil, makes sense. I have a SPL radio shack meter I get out now and then, very handy little tool. I have a "perceived" volume drop in my xo EHX Octave Multiplexer, but I'm not sure if it's really volume loss, or because the signal is going an octave lower, than it's a percevied volume loss. I'll have to use the SPL on that and see what I find. Even if it isn't a volume loss, it appears to be, because the upper mids are greatly reduced, and the bass increases, which may not sound as loud. Robo has offered to add a volume boost to the pedal, which could be a good thing.

                              Comment



                              Working...
                              X