Members Gorquin Posted June 11, 2012 Members Share Posted June 11, 2012 don't underpower your speakers or else they'll blow The engineers in the group can correct me if I'm wrong but from my experience I'll say this. You can blow a pair of speakers that will handle 100W with a 20W amp. How? When you crank that 20W amp into clipping you now produce a flat sine wave...a square wave. Multiply that wave by 10K or 20K times and you now have a DC voltage running on top of your AC(music) which heats up the voice coil and can cause it to burn up, short, and even short your amp. I've seen it plenty of times in home and car audio. I did contract work for more than 17yrs directly with from the Mfg.'s doing between 18K-26K units/yr. Yes...you can blow a spk by underpowering it IF you crank it to the max.! Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 11, 2012 Members Share Posted June 11, 2012 Yur wrong. I've got a Bugera 1960 150watt tube amp sitting here in front of me connected to a 600w rated 2x12 . With the channels hooked in series (Randy Rhodes mod) ain't nothin' but peak-to-peak square waves coming out of it and no problems so far except for being a wee bit on the stoopid loud side . Link to comment Share on other sites More sharing options...
Members Gorquin Posted June 11, 2012 Members Share Posted June 11, 2012 Explain please your answer. If you take a 9V battery and place it across a speaker....it stays in one position (depending on polarity) because of the DC current running into the voice coil. Why isn't clipping at 10khz-20khz on top of an AC signal going to do the same thing? Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 11, 2012 Members Share Posted June 11, 2012 Explain please your answer.If you take a 9V battery and place it across a speaker....it stays in one position (depending on polarity) because of the DC current running into the voice coil. Why isn't clipping at 10khz-20khz on top of an AC signal going to do the same thing?What exactly does the former have to do with the latter? Link to comment Share on other sites More sharing options...
Members Marko Posted June 11, 2012 Members Share Posted June 11, 2012 Blowing a speaker by abusing it with a distorted signal is not Link to comment Share on other sites More sharing options...
Members SpaceNorman Posted June 11, 2012 Members Share Posted June 11, 2012 But Duracell batteries definitely sound better than energizer. I can't explain why - but this is definitely the case with my Roland AX Synth keytar and M-Audio wireless MIDI setup. On a couple of occasions - poor planning on my part demanded that I try "make it work" with Energizers. It simply doesn't fly. Loading the keytar and wireless transmitter with Energizers inevitably means a night of dropouts, "patch reversions" and other weirdness. Note that "Patch Reversion" is my term for how my keytar behaves when it gets anywhere near the edge of it's wireless range - when it gets to that edge - it first drops whatever voice was being used and reverts to the "Bank #1, Program #1" patch (simple piano). Take 3 steps further away - and it drops the signal completely. With a fully charged set of Duracells the edge of wireless coverage is about 25-30 feet from the wireless MIDI receiver (with clear line of site). With a set of fully charged Energizers, I experience "patch reversions" even though wireless MIDI transmitter and receiver are within 6 feet of one another with a clear line of site. Load it with Duracells - and that never happens. I've metered the individual batteries afterwards ... and confirmed that the Energizers were all fully charged - and duplicated the behavior in another location (which in my mind eliminates the likelihood that is was an interference thing associated with the venue itself). Given my experience - if I don't have a set of Duracells (or these days, Duracell Rechargeables!) - I don't even bother opening the keytar case. Like virtually all this electronic stuff - I can't explain the underlying science - but I can recognize and isolate the behaviors to the point that there's little room for doubt that there IS a difference. Link to comment Share on other sites More sharing options...
Members Gorquin Posted June 11, 2012 Members Share Posted June 11, 2012 OK, I learned something new today There's no DC on clipping but the result of clipping CAN cause speaker damage.This info from QSC explains a number of scenarios. http://forum.qscaudio.com/forum/viewtopic.php?f=29&t=2736 Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 11, 2012 Members Share Posted June 11, 2012 "And everybody lived happily ever after" Link to comment Share on other sites More sharing options...
Members dboomer Posted June 11, 2012 Members Share Posted June 11, 2012 There's no DC on clipping but the result of clipping CAN cause speaker damage.http://forum.qscaudio.com/forum/viewtopic.php?f=29&t=2736 But as Bob explains ... it's not the "clipping" but rather the "power" than can result. The waveform itself is not a problem Link to comment Share on other sites More sharing options...
Members jwlussow Posted June 11, 2012 Members Share Posted June 11, 2012 Here is a myth... Passive speakers are better than active speakers. Here is another one... Active speakers are better than passive speakers. :phil: Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 12, 2012 Members Share Posted June 12, 2012 The waveform itself is not a problem Except for the harmonics generated in the higher frequency ranges which can cause unintentional overpowering of HF drivers. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 12, 2012 Members Share Posted June 12, 2012 ^ Yup. Link to comment Share on other sites More sharing options...
Members dboomer Posted June 12, 2012 Members Share Posted June 12, 2012 Except for the harmonics generated in the higher frequency ranges which can cause unbintentional overpowering of HF drivers. Again ... power, not waveform Link to comment Share on other sites More sharing options...
Members stunningbabe Posted June 12, 2012 Author Members Share Posted June 12, 2012 Here is a myth... Passive speakers are better than active speakers. Here is another one... Active speakers are better than passive speakers. :phil: agree! Link to comment Share on other sites More sharing options...
Members himilcyclr Posted June 12, 2012 Members Share Posted June 12, 2012 Thanks Mark! I needed that.1) The heavier the gauge of the cable, the better and 16ga. wire is bigger than 12ga.2) Gear condenses moisture when taken out of a warm room to freezing temperatures outside.3) Digital is pure and perfect.4) Horizontal arrays spread the sound wider.5) Differences in types of connectors is just a marketing scheme.6) TRS jacks and plugs are stereo.7) Cupping a microphone makes your vocals louder.8) Running amplifiers in bridge-mono is the best bang for the buck.9) Technology (more gadgets) and fixing it in the mix is the solution to any sound problem.10) A 4-10 guitar amp sounds better than a single 12 guitar amp.11) If a microphone is feeding back, cup your hand over the windscreen.12) Gaff tape, duct tape... just different names for the same stuff.13) All electrical outlets at commercial venues are inspected and are "fine", and: "Bands play here all the time" is assurance enough that the power is a-ok. And: "Bands play there all the time, so there's gotta be plenty of power in the vacinity of the stage, and load-in should be easy."14) Louder is better. Also: If the crowd seems lackadaisical, it's obviously not loud enough.15) Leo Fender invented the electric guitar, and got his start building electric guitars, and then branched out into other products.16) The black wire is negative, the white wire is positive.17) Drums should be tuned relative to how it sounds on the drummer's throne (admittedly... this myth is seldom if-ever verbalized, and even more rarely challenged).18) "Soundchecks."19) Transporting "band gear" is exempt from DOT regulations.20) "It's portable because it's got handles on it."21) Gold is the best electrical conductor.22) Cables (especially speaker cables) should be the same length... it's a time alignment thing.23) Amplifiers make power. Also: Amplifier "RMS rating". Also: The maximum amplifier wattage output capability is that which is listed in the specifications.24) Xmax relates to the maximum cone travel of a speaker based on the speaker's suspension properties.25) "Borrowing" gaff tape.26) "It's probably just a bad fuse".27) "Speakon wiring standard". Also: "Those Speakon cord ends are male gender".28) "We'll have plenty of capable helpers at the venue to help with your load-in and load-out." And: "Parking won't be a problem, we'll have a permit for you".29) There's no need for weather contingencies because there's no rain in the forecast.30) "Sound engineer".31) "You'll be able to reach me on my cell phone."32) "It looks like it will be an easy gig". And the first corollary is: "It's an easy gig, honey... I should be home by 2:00 am."33) "That was an easy fix. (I can't imagine why the repairman's quote was so high... a dousing of contact cleaner fixed those slide pots just fine.)"34) "Speakers need to be properly broken in."35) "They (this band) will keep me as a full share partner in the band when they're signed."36) "Nobody will be back here (where the cable slong-pile is)."37) "I've worked with these acts before... they'll all share the same backline gear... change-overs will be easy."38) "This is their current stage-plot and input list."39) Directional cables.40) I can design and build speaker cabinets cheaper and better than off the shelf models made by big maufactures.41) "ATA certified."42) The best place to mix is up on a riser in the middle of the room. And: The best place (acoustic wise) to put the band is in the corner of the room.43) "I always mix better after I've had a few."44) "Nobody will drive here... this is a good location to run the snake."45) "Surely they'll cancel the gig... nobody would go forward with a show in this weather."46) "I can make-up for the lost time on the road when I get to the gig."47) P=E/R48) "I don't need directions to the venue, I have GPS."49) "The stage will be in-place by noon." And: "The port-a-potties will be there first thing in the morning." And: "We'll have a suitable festival generator (as per your specifications) at the venue." And: "That's all the RV's that will be arriving and plugging in." And: "Our people will be on-site by 6:00am."50) "Ok... I know you required 1/2 up front, in cash... but here's a check for the 1/2... it's good, you can call my bank... the other half shouldn't be a problem based on advance ticket sales."51) "You can hang a banner from the stage (in-lew of actual pay)... that should be great advertising for your company. We're expecting a huge turn-out."52) "I'll put in a good word for your company."53) "The bid will go to the lowest bidder that meets the bid specifications and has a proven track record."54) "You lost the bid due to some situations beyond my control... I don't know how to explain, except there was some back room stuff going on... you understand, right?" Link to comment Share on other sites More sharing options...
Members WynnD Posted June 12, 2012 Members Share Posted June 12, 2012 It depends on the application. 1/4" instrument cables can have a big effect of the sound of a guitar plugged into an amp. I don't believe that the human ear is sensitive enough to tell the difference and even with a good oscilloscope you would barely be able to tell a difference. But you are allowed to fool yourself and as long as you're not spending my money to do it, get whatever cable you want. Link to comment Share on other sites More sharing options...
Members Mutha Goose Posted June 12, 2012 Members Share Posted June 12, 2012 I don't believe that the human ear is sensitive enough to tell the difference and even with a good oscilloscope you would barely be able to tell a difference. But you are allowed to fool yourself and as long as you're not spending my money to do it, get whatever cable you want. For a guitar with passive pickups, the quality of the cable will have a direct and clearly audible affect on the high frequency roll-off. Link to comment Share on other sites More sharing options...
Members Gregidon Posted June 12, 2012 Members Share Posted June 12, 2012 Correct. The higher the output impedance of the pickup, the more dramatically the cable will affect the sound. I've run into this especially with super high impedance piezo pickups. Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 12, 2012 Members Share Posted June 12, 2012 I don't believe that the human ear is sensitive enough to tell the difference and even with a good oscilloscope you would barely be able to tell a difference. But you are allowed to fool yourself and as long as you're not spending my money to do it, get whatever cable you want. You are applying one set of criteria to a different situation. For a passive guitar or even a passive bass, especially one with very high impedance pickups, the specifications for the cable can have a great impact on things like high frequency response (due to LC interaction), flatness (due to LCR interaction), noise (due to shield effectiveness), mechanical noise (due to dielectric construction), all of which will be made more noticeable with longer lengths. Link to comment Share on other sites More sharing options...
Members stunningbabe Posted June 12, 2012 Author Members Share Posted June 12, 2012 You are applying one set of criteria to a different situation. For a passive guitar or even a passive bass, especially one with very high impedance pickups, the specifications for the cable can have a great impact on things like high frequency response (due to LC interaction), flatness (due to LCR interaction), noise (due to shield effectiveness), mechanical noise (due to dielectric construction), all of which will be made more noticeable with longer lengths. Andy...how come you know so many things?? Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 12, 2012 Members Share Posted June 12, 2012 Andy...how come you know so many things?? Because I have designed product for this industry for over 30 years and have an electrical engineering degree. It's my day job. Link to comment Share on other sites More sharing options...
Members W. M. Hellinger Posted June 12, 2012 Members Share Posted June 12, 2012 You are applying one set of criteria to a different situation.For a passive guitar or even a passive bass, especially one with very high impedance pickups, the specifications for the cable can have a great impact on things like high frequency response (due to LC interaction), flatness (due to LCR interaction), noise (due to shield effectiveness), mechanical noise (due to dielectric construction), all of which will be made more noticeable with longer lengths. Let me add: I personally believe, while subtle (or even not-so subtle) differences in guitar "tone" may not be perceivable (or even blatantly obvious) to the casual audience member, I believe some guitarists may be "hypersensitive" to differences in their guitar tone. The word "hypersensitive" isn't quite the "right" word... but it kind-of is, in-that the guitarist is in a position to be hypersensitive (more sensitive than others) due the positive feedback loop they're immersed in that's MOL unique to electric guitar playing. And there's aspects to "tone" that can supersede (go beyond) that which a person can accurately identify strictly from a "listening" standpoint. Bottom line is: If a guitarist likes the sound of one guitar cable over another, it Link to comment Share on other sites More sharing options...
Members Gorquin Posted June 12, 2012 Members Share Posted June 12, 2012 When I learned about the clipping issue and DC(from an Elec. Eng.) it was in the late 70's. We still worked on a lot of tube amps, early transistor units, and units that still had nuvistors in them. A lot of those early units didn't have a DC offset pot. The article also states "However, a significant DC offset on an amplifier output is undesirable for several reasons: because it will dissipate power in the voice coil without producing any acoustical output; because it may cause the voice coil to travel out of the magnet gap, which would reduce the cooling; and because it shifts the driver Link to comment Share on other sites More sharing options...
Members tlbonehead Posted June 12, 2012 Members Share Posted June 12, 2012 I'm not anal enough to worry about the brand of guitar cord. But Duracell batteries definitely sound better than energizer. as long as they are about 3/4 used up. Link to comment Share on other sites More sharing options...
Members tlbonehead Posted June 12, 2012 Members Share Posted June 12, 2012 So it's in the 700 mhz range, nobody will catch me. . not yet anyway!! No noise issues yet either. Yet.... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.