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Everything posted by Bill Fitzmaurice
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No. Let's say the frequency is 100Hz. That means the cone must go from rest to full outward excursion to full inward excursion and back to rest 100 times per second. If it does so over a distance of, say, 6mm it must move six times faster than it does over a distance of 1mm. How cone velocity can affect the result is explained here: http://www.readresearch.co.uk/loudspeaker_papers/klipsch_modulation_distortion_article_1.pdf
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That's what Chris Squire did as well. I doubt he used a crossover. He probably just plugged into both. Most amps of that period had parallel input jacks, making it very easy to daisy chain amps.
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Xmax is the distance the cone can travel before distortion becomes severe. The longer the xmax the louder it can play. The best way to compare different drivers is with speaker modeling software. The program I use the most for sealed and ported cabs is WinISD 0.7. With it you can see the effects of the box size and tuning, and see Maximum SPL, which is determined by both the voice coil power limit and xmax.
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Neither of those are 200 watt, so I suspect those in the video are B102 or BP102. The magnet in the video also looks too large for the frame to be a twelve. It's true that one doesn't need a 32Hz F3 for low B, no more than does anyone need a 41Hz F3 for low E. But low B is still more demanding than low E, so I'd want at least 6mm xmax for low B use. 6mm xmax is usually going to cost more, but my philosophy is buy once, cry once.
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For -3dB at 40Hz would require an internal box volume of 300 liters, exclusive of the space taken up by the port and the drivers. You don't necessarily have to go that low, a 50Hz F3 from a net box volume of 200 liters would suffice. But with less than 200 liters the low end would fall off rapidly. There's also the matter of the 4.4mm driver xmax. That's adequate for the most part with a low E, but not with a low B.
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That's ported. Measuring frequency response is done with software, like HolmImpulse, and a USB measurement mic. The Beta 12 is an entry level driver, so whether it's adequate for your needs only you can say.
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With a proper balanced interconnection there's no need to lift the ground, that's one of the advantages of balanced. That said, not all devices are correctly configured. Have a look here, scroll to page 216. https://www.yumpu.com/en/document/read/25666510/ranenote-collection
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There's no point to bi-amping similar speakers. The difference in the low frequency limits would have to be close to two octaves to make it worthwhile.
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+1. One can be perfectly fine with a 30 watt Ampeg B-15. One thing you can be sure of with respect to watts: the more someone dwells on their importance the less they understand about amplification. They probably can't even recite Ohm's Law from memory.
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Assembled in the US from components sourced in Asia. That's not the same thing as made in the US, not that anything is, any more than is anything made in GB.
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Maybe. The problem when you use non-specific subjective terms is that there's no real definition, and therefore no agreement, on what it means. That greatly increases the difficulty of realizing whatever it is that you're trying to get.
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Cheap Lightweight Speakers On The Way?
Bill Fitzmaurice replied to Phil Starr's topic in Amps and Cabs
And the downside? 😊 -
Cheap Lightweight Speakers On The Way?
Bill Fitzmaurice replied to Phil Starr's topic in Amps and Cabs
That had little to do with mineral rights, which American and other companies can and do get from the Greenlandics. It had to do with the Northwest Passage. Thanks to the global warming that Trump labels as a hoax it's gone from 19th Century fantasy to 21st Century reality. In theory whoever controls the sea lanes within Greenland's territorial waters would have a strategic and economic advantage as more and more commerce goes through those waters from Asia to Europe. As usual Trump didn't think it through. It never occurred to him that the inhabitants of Greenland wouldn't go for it, even if the Danes did. If there's a change from the status quo for Greenland, currently an semi-autonomous possession, it will be to full fledged nationhood. It wasn't the most harebrained idea Trump ever had, but that list is a very long one. -
If you're familiar with the innards of a vintage valve amp you've got perfboards that components are mounted to, with discreet wiring to the valves, pots, transformers, jacks and so forth. Even if the perfboards were loaded with their components in Asia, probably Viet Nam, that would still leave a lot of wiring to be done. Making a big deal about them being hand wired is advertising blather, because that type of construction can only be hand wired. It's a completely different form of construction from circuit boards, which can be configured so that all the components, including the pots, jacks, valve sockets and power supply, are directly soldered to the boards, usually via wave soldering. In some cases there's only one board, so there's very little plugging in to do.
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Without measured response charts SPL ratings are worthless. The figure could be a broadband average, it could be at the highest point of the curve. What you can assume that it's not is the SPL at 80Hz, which is where bass cabs should be rated.
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Assembled in the USA means assembled from parts made in Asia. That applies to just about everything these days.
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Cheap Lightweight Speakers On The Way?
Bill Fitzmaurice replied to Phil Starr's topic in Amps and Cabs
Despite the rare earth name neodymium isn't rare and it isn't all that difficult to refine. China is the main producer, for the same reasons China is the main producer of just about everything. The Chinese decided to take advantage of their near monopoly and jacked up the price. In response other countries have ramped up their mining and refining. The US is predicted to exceed Chinese production within the decade, while Australia, India and even Greenland are stepping up production. As for its use in the loudspeaker industry, that's a mere drop in the bucket. The main consumers are the auto industry for use in motors for electric vehicles, and the wind power electric generation industry for use in generators. -
Double post, tried to delete the second one, I guess this forum software doesn't have a provision for that.
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The clip indicator is probably reacting to the in initial attack. Since it's a power amp, not an instrument amp, the indicator is probably calibrated with the expectation of the signal being compressed.
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Your 60s unit was hand wired too. 😉
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If they weren't isobaric they'd be even larger. They may not seem small today, but they were by the standards of their time. This is a quote from the Linn product information sheet: Each speaker has two of each drive unit fitted – i.e. two bass, two mid and two treble. The second bass unit is hidden inside the cabinet, behind the visible bass unit and this forms the basis for our patented Isobarik equal-pressure bass system. This means that the front speaker behaves as if it is in a much bigger enclosure.
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Understood, but it shouldn't take him more than a song to sort it out, if not in sound check. IME the problem is sound men who don't know what they're doing, and I've seen them from pub gigs to stadiums. The best FOH engineers I've worked with tended to be bass players and recording engineers, if not both. One I knew who was particularly good, he was working with 'Journey' when I met him, would automatically high pass the bass at 60Hz, knowing that doing so would make the bass through a monster PA still sound like a bass. If they all did so it might make going to concerts an enjoyable experience again.
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Flapping / distortion from rig combinations
Bill Fitzmaurice replied to bigjimmyc's topic in Amps and Cabs
That's what happens to a sine wave, but music doesn't consist of sine waves. With music content what happens is that whether it's an amp, a stomp box or a speaker there comes a point where there's not enough rail voltage and/or driver excursion to go any louder in the low frequencies, so they don't get louder with additional signal applied. The midrange and high frequencies do get louder, and that changes the tone. When you do that using a Les Paul through an AC30 and Greenbacks that tonal change is for the better. When it's a PBass through an SS amp and tweeters it's like nails on a chalkboard. This is why you shouldn't use tweeters if you employ distortion, and why AC30s don't have tweeters at all. -
Flapping / distortion from rig combinations
Bill Fitzmaurice replied to bigjimmyc's topic in Amps and Cabs
Not exactly. Clipping doesn't send a square wave, no more than a pristine signal sends a sine wave. In all cases what's sent to the speaker is a complex wave form. What differs when the signal is clipped is that there's a lot of midrange and high frequency harmonic content present that's not in the original signal. With bass that can sound nasty, especially if you have tweeters. With guitar it's the Holy Grail. -
Flapping / distortion from rig combinations
Bill Fitzmaurice replied to bigjimmyc's topic in Amps and Cabs
That's a straw that an oddiophile or amp salesman might grasp, but unless you're running 50 meter or longer speaker cables damping factor is a non-factor. Besides, the damping factor of valve amps being much lower than SS it wouldn't explain the OPs situation. However, while his YBA-200 amp doesn't have Fender/Marshall circuitry it does have the same style of passive tone controls, which along with natural compression and high passing leaves me to believe that's the difference. It's not without good reason that heavy iron valve amps remain the standard for tone, if you can manage to lift them, or even better have roadies to do it for you.