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Bill Fitzmaurice

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Everything posted by Bill Fitzmaurice

  1. By and large separates work better, and always have. Combos usually sacrifice function for the sake of a small form.
  2. +1. Of all the factors that combine to determine how loud a rig will go power is the least significant. Those who are unaware of this basic rule are playing into the hands of 'the more watts', which is to say the more expensive, 'the better' marketing departments.
  3. Penn Elcom used to have one but I don't see it on their site now.
  4. I already explained it. It's the same as having a 1000 amp breaker at the nearest breakout transformer, followed by a 100 amp breaker on the service entrance, followed by ten amp breakers at the individual branch circuits. It adds one more layer of redundancy. For whatever reason the UK decided that extra layer of protection was warranted, while most of the rest of the world did not. I guess it's like wearing both a belt and suspenders, you halve the likelihood of your pants falling down. 😉
  5. That appears to be a ground fault circuit interrupter, GFCI for short. https://simple.wikipedia.org/wiki/Residual-current_device In the US they're usually built into the wall socket, where they've been a code requirement in kitchens, bathrooms, basements and outdoors for at least 20 years. They're often built into hairdryer leads as well, in the event they're used near a bathroom sink with an old outlet that's not GFCI protected.
  6. There's some logic to fusing the cord. For example, assume that the breaker for the branch circuit that the outlet is on is 10A. Assume that a device plugged in to that outlet is uses a lead that's rated for 5A. A fault in the device or its lead could pull more than 5A, enough to perhaps start a fire, without tripping the breaker.
  7. Assuming the 15 stands for 15 watts it's no more than a 3 amp fuse. 13A at 230v is 2990 watts.
  8. The more likely scenario is that they stick the Eden name plate on inexpensive Asian imports to make them appear legitimate. That's what GC did with Acoustic, not to be confused (though they endeavor to so so) with Acoustic Control Corporation.
  9. Power supply caps have a shelf life of 25 odd years, so it your amp is that old or older they could probably stand replacing. With vintage amps you might be able to upgrade the caps while replacing them, as capacity for a given physical size has gotten better over the last half century. Otherwise a periodic vacuuming of dust, lubrication of the pots and cleaning of the jacks is all you need be concerned with.
  10. I wouldn't do a 4x12 at all. In 1977 they used four twelves because they had to. There's no need for four twelves with modern drivers. A 2x12 is sufficient for all but the very largest venues, and for those a pair of 2x12 vertically stacked will work far better than a 4x12. For that matter a well designed 1x12 is sufficient for the average club venue. That's what I use.
  11. I'm not aware of any. Crossfiring can work well with guitar, where the cab interior size doesn't need to be large, but not with bass. The speaker jacks are an unusual arrangement. The main speaker out connects to a 4 ohm tap on the transformer. When both jacks are used they're in series, connected to an 8 ohm tap. When the extension jack only is used it connects to the 8 ohm tap, so with a single 8 ohm cab it should be plugged into the extension jack. I can't say why they did this, the circuit is almost identical to the Twin Reverb and Dual Showman, which ran parallel jacks with a 4 ohm tap and were just fine with a pair of 4 ohm cabs. I chalk it up to being another of the oddities of CBS era Fenders. I've never used LaVoce, although they look OK. Their cab designs are all PA, and are nothing out of the ordinary.
  12. The angling in of the drivers is actually better than forward firing as far as midrange and high frequency dispersion is concerned, but the more or less halving of the cabinet rear chamber volume killed the low end, such as it was with those drivers.
  13. If it's one of these cabs pass on it: https://reverb.com/item/387356-79-fender-bassman-135-and-4x12-cab-near-mint It was quite horrid. The inverted pyramid baffle made the cabinet interior volume too small, the drivers were guitar drivers, and the joints between the baffle sections were prone to failure.
  14. Most amps have de-facto high pass filtering, even if it's not via a separate high pass filter per se. Most electric bass speakers don't go really deep, a necessary trade off to realize high sensitivity. Precise mating of amps and speakers to the exclusion of other brands would be counter-productive, as most users tend to buy one or the other, to use with an amp or speaker they already have.
  15. That brings up another point. The speaker power rating is thermal. The mechanical rating could be far lower, as much as 60% lower being not unusual. Speakers with a mechanical rating even approaching the thermal rating are rare and expensive.
  16. Not necessarily. That's often the case with 2nd order/2nd order, but not always. In any event it's prudent to test the system both ways just to be sure, playing a test tone at the crossover frequency.
  17. From the consumer's standpoint, and from a marketing standpoint, true. It's like touting horsepower in a car, even though torque is far more important. From an engineering standpoint failure to understand and apply these concepts in the design stage often leads to failure of the product. I believe this is at the root of the problems Ampeg had with new products some years back.
  18. That's one possibility. There's also mechanical compression, where the speaker has run out of excursion, so additional input doesn't give additional output. The same can happen with the amp. In practice all three can occur simultaneously, especially with guitar amps, in which case it's often intentional, although the player probably has no idea why he's getting the result.
  19. I specify the BGH25-8 in my Simplexx bass cabs. In part that's because it doesn't extend higher in response than what electric bass needs, reducing hiss, in part because with a 2nd order low pass/4th order high pass crossover it can run to 2kHz. That eliminates the typical upper mids hole in cabs that cross over an octave or more higher, and provides dispersion above 2kHz that no woofer can match.
  20. Power is determined by voltage and current, P= V x I. Neither power nor current define how loud a speaker will go. Current, and therefore power, is determined by the load impedance, and the load impedance of a speaker isn't constant, it varies with frequency. With the exact same decibel level you can be running 100 watts into the speaker at one frequency and 5 watts at another frequency. The reason why they're at the same level is because voltage determines level, and voltage doesn't vary with the impedance load. We really should never be talking about watts, always about volts, but that bridge was crossed and then burned almost 100 years ago, so there's no going back now.
  21. True, though the required reinforcement may also be carbon fiber, keeping the weight down. What this results in is a more labor intensive building process, which is in part why CF is so expensive. The other reason is that CF itself is expensive, because most of what's available is being used by high volume users like Boeing and Airbus, even Tesla. A small speaker company can't compete with them for buying power. At the other end of the scale the reason why 18mm plywood has long been the staple material is because you can get away with minimal bracing, which cuts labor cost, which keeps overall cost as low as possible, at the expense of weight.
  22. Technically speaking the primary reason the sound on stage and in the room is different is boundary reflection sourced cancellations. When the distances between you, the speaker and the walls and ceiling are relatively short these cancellations make the low end thin. Out in the audience, where those distances are much longer, cancellations aren't as severe, if they exist at all, and the low end is fuller. If you're boosting the lows to get a full tone on stage it can be too much out front. That doesn't mean twiddlers and their subs aren't a problem. They are, mainly because the range of subs goes a full octave lower than bass cabs. Sound men who know what they're doing account for that by high passing the bass channel strip somewhere between 60 to 80Hz.
  23. This repeats the common misconception that the doubling of current delivery, which results in a doubling of power, into two cabs versus one has anything to do with the 6dB increase in output. It doesn't. As I already noted what determines loudness is cone displacement, which is determined by voltage swing, which is the same into either one or two cabs. Level voltage into twice the displacement gets 6dB. The only limitation to this is when the amp is being run full tilt. Most amps are not be able to maintain the same voltage swing into two cabs as one when they're running at full capacity, due to power supply sag. But at volumes that aren't taxing the power supply you'll get 6dB every time. I'd be inclined to think it's the amp. Distortion on the low notes happens when the speaker runs out of excursion and/or the amp runs out of headroom. If speaker excursion was the problem it should happen with both amps. Another possibility is that the bass EQ of the GK was considerably higher than the Elf. That would cause both the amp and speaker to run out of headroom at a lower overall level than with the Elf. The way to test that is to try both amps at low volume, setting their EQ to sound as much alike as possible, and then see what happens when you take the volume up.
  24. Wishful thinking, in no small part because the sound out in the room can vary wildly from the sound on stage. For that reason I do my personal sound check with a long enough cord so I can stand well out onto the dance floor. If that results in it being shite on stage I live with it, because what the audience hears matters far more than what I hear. If there is a knob twiddler in play I listen to his mix at the FOH to be sure he's not totally fouling up the works. IME at even the highest echelons maybe half the FOH engineers get the bass right. Most of those who do are also either recording engineers or bass players, if not both. When faced with the option of either leaving a concert early or going medieval on the twiddler's buttocks it's almost always because he's ruined the bass mix. Come to think of it, the only recent exception was when I had to walk out on Willie Nelson. He's a genius writer, a good vocalist, but the worst guitar player I ever heard. I swear he played every song in a 7/11 time signature, even though his band was attempting to play in 4/4 despite him.
  25. Pre or post your speakers aren't going to sound the same as the PA, so it doesn't matter that much, as the board channel EQ likely won't be run flat anyway. Which means that your out front tone is at the mercy of the sound guy anyway...😫
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