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Bill Fitzmaurice

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Everything posted by Bill Fitzmaurice

  1. Don't need those either, especially of the Cheeto variety. 🤔
  2. Clipping will never bother a PSU. Too low an impedance load can if the amp is not protected against it, while sending a high level signal into an amp input can damage pre-amp components that aren't able to handle high current sources. When they fail they can take out the PSU as well, but clipping has nothing to do with it.
  3. Clipping is clipping, with both cause and effect being the same, no matter where it occurs in the signal chain. The only reason to have a clipping indicator is to warn the user of the potential for tweeter damage. Ever wonder why guitar amps don't have clip indicators? For one thing they don't use tweeters. For another they're usually clipping. Why?
  4. If it says 'Minimum Load 4 ohms' that indicates an SS amp. Modern SS amps do not have output transformers.
  5. You probably hear it at every gig. It's what constitutes everything from what bass players call 'grind' to what guitar players call 'sweetness', let alone anything involving overdrive. Clipping can't harm an amp. A distortion pedal is an amp in a state of perpetual clipping.
  6. Clipping doesn't hurt anything other than tweeters, and they'll sound nasty long before they should blow. What you, and your (idiot) guitar'd player should be concerned about is hearing loss. I'd say ask Pete Townshend, but you wouldn't get an answer, he can't hear the question.
  7. 3dB isn't much, but that was referring to the increase in output with no changes to the amp setting. The additional 6dB of maximum output, when both drivers reach their mechanical limits, is substantial.
  8. There's no such thing as ohmage. Ohms are used to measure resistance, impedance, capacitive reactance and inductive reactance, so if one says' ohmage' it could refer to any or all of those factors. Adding a 4 ohm cab to an 8 ohm cab won't cause anything to blow, assuming the amp is rated for the resulting 2.67 ohm impedance load. Adding a second identical 8 ohm cab will result in a 3dB sensitivity increase compared to a single 4 ohm cab, assuming the drivers are identical save for their impedance. The pair of 8 ohm cabs would have twice the driver displacement of the 4 ohm cab, so they would have 6dB higher maximum output capacity.
  9. Not if it's tuned wrong. How it will work with a driver for which there are no T/S specs is anyone's guess. If you want an inexpensive cab there's plenty of used available.
  10. Headphones have flat response, bass cabs are anything but flat. What sounds good through the one will never sound good, or remotely close to the same, through the other.
  11. Judging by the copied and pasted 'Features' it's the same driver. Since there are no T/S specs, and I very much doubt the builder has the gear or know how to measure them himself, there's no way the cab could have been properly designed. I can't imagine the size of the ports was arrived at by any method other than 'they fit my hands'.
  12. I don't know if it's an Alpha, but at that price it wouldn't be anything more substantial than that.
  13. The Alpha 12 weighs 2.4 kg, the Deltalite II 2512 2.3 kg, so neo doesn't always mean lighter weight. A Delta Pro 12 is 7.4 kg, so that's the price/performance range where neo would save weight. Still, the most weight savings come from using well braced 12mm plywood, rather than sparsely, if braced at all, 18mm.
  14. You mean SLA Pro? The ports aren't ducted because the cab is tuned to 95Hz, for maximum sensitivity and output above 85Hz. That's perfect for mating with subs to handle below 100Hz in a full range PA system, or for use without subs when there's no low frequency content. You'd never want a bass cab tuned that high.
  15. If you have a good PA then your back line cab is more of a personal monitor, as it no longer needs to drive the entire room by itself. There's no reason why you can't still use a 2x15, but if your gear hauling capacity is limited the pack space that 2x15 takes up would be better served carrying a larger PA.
  16. I can't speak to his motives, but I can speak to the engineering. Since a ported cab needs ports and it needs handles it's practical to combine the two where it makes engineering sense. In a bass cab it doesn't. For a port to double as a handle it can't have a duct. Without a duct the port area must be quite small to tune the cab low enough for bass. The problem is that too little port area leads to chuffing noise from the port, while a non-ducted port large enough to not chuff can't tune the cab low enough for bass. I use port handles only in PA tops that are tuned much higher than bass cabs, as those tops are meant to be used with subs handling the lows.
  17. That will only put undue strain on your 2x15. Get a proper PA, because the lack of definition lies in the midrange and high frequency quality of the PA, not the lows.
  18. I have serious doubts that he knows what he's doing. For instance: The two bass vents act as side handles. They are positioned to let cooling air flow to the speaker. On stage they send low frequency sideways which doesn’t muddle the sound you hear. The output of ports is 100% omni-directional. For that matter from a cab of that size the direct output from the cone is omni-directional below roughly 250Hz. 🤔 There are a number of other issues with his claims, but this one alone is enough to convince me that you should probably avoid them.
  19. They'll work, but they're not matched. There's a difference. In any event mid cancellation on the horizontal plane happens when either drivers or cabs are placed horizontally. The cure is easy, don't do that.
  20. That will cause low frequency cancellations. Put one cab on the floor, aimed at the drummer, for him to hear. Put the other on top of it aimed at you for you to hear.
  21. A full crossover really isn't called for, as this isn't a sub/midbass arrangement as you have with PA. In order to make best use of it I'd set the sub low pass between 200 and 500Hz, whatever sounds best. There won't be any phase issues between the sub and the 112s with the sub only working that high, it's only above 800Hz or so where phase interactions between different drivers operating in the same pass band can cause more harm than good.
  22. The line out will drive a sub, and as the sub should have its own volume control so long as the line out from your amp is post-volume control it will control both. However, for the sub to be worthwhile it would have to be at the very least a 115, if not a 118, with at least twice the power as your ABM.
  23. You may have seen somewhere that the inherently low damping factor of tube amps works better with sealed cabs, but it's not true. This explains why damping factor is a non-issue: www.cartchunk.org/audiotopics/DampingFactor.pdf
  24. Not knowing the exact topology of the cab I really can't say, other than it might be a dual chamber reflex. Many examples of dual chamber reflex can be found on line.
  25. By your description it may be a dual chamber reflex. If that's the case the first mention I recall of it was in a book by David Weems, circa 1980.
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