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Everything posted by Bill Fitzmaurice
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It could, as thermal power is limited mainly by the gauge of the coil. However, as you pointed out, to realize 126dB at 62Hz would require an xmax in the vicinity of 25mm with at least 96dB sensitvity. There's no such thing as a driver with 25mm xmax that has 96dB sensitivity. A 25mm xmax driver might have 86dB sensitivity, reducing maximum SPL by 10dB. Phil is being kind to say that they're trying to deceive. I'm more inclined to call them as I sees them. They're peddling a load of BS. The combination of 126dB continuous (dB SPL @ 1m) with frequency response: 62 Hz – 20 kHz (±3dB) from an eight inch woofer loaded cabinet of that size is impossible to realize, by a very wide margin.
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For Larry Hartke (if he visits here)
Bill Fitzmaurice replied to Zombie1965's topic in Amps and Cabs
The demise of Hartke was predictable when it was taken over by Samson. It was only a matter of time before the bean counters ruined a good brand. It's similar to what happened to Ampeg with LOUD, and what will happen to Turbosound with Behringer. -
https://billfitzmaurice.info/forum/
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You need a break out panel. My assumption is that you don't know what that is. Go to my forum and ask there in the Pro Sound Setup section. This wiring may be Greek to you but not to the PA gurus on my site. It's how most of them run their rigs, because it is conventional with large touring systems..
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+1. No matter what he was playing with and through Jaco always sounded like Jaco.
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There's a lot more to funk than EQ. Bootsy and Rocco aren't defined by their tone, they're defined by their chops. The thing you don't want to do is have too much low end, as that doesn't work well with staccato technique. With funk the bass isn't a background instrument, it's a lead instrument, so it should be mid prominent.
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The XLR are a means to send signal to the sub driver without using the speakons. They also could be used to link sub to sub, and main to main, assuming the mains panels look the same.
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If that results in one amp channel powering both speakers don't do that. If you don't split the lows to the subs and the rest to the mains with an electronic crossover the system simply won't work as it should. All you're risking is blown drivers, as well as bad sound. Ohmage is what you pay to Jack Bruce, Entwhistle, even Sir Paul. Speakers have impedance. You must bi-amp, either using a single two channel amp with one channel for the subs and one for the mains, or using a pair of two channel amps, one amp for the subs, one for the mains.
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The design isn't unusual, you're just not used to dealing with passive subs/mains that require bi-amping. I recommend this exact 4 pole speakon wiring in all my passive subs and mains. It's also the most commonly used arrangement in high end commercial passive PA.
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They don't do that. Using the speakons there's no connection between the drivers of the subs and the drivers of the mains.
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Every PA manufacturer should have that information contained with their owner's manual. AFAIK none do. I posted similar information on my forum in 2006, less than two months after I started it. https://billfitzmaurice.info/forum/viewtopic.php?f=10&t=398
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Make sure of what poles are connected to what. Remember it requires two amps, or two channels of one amp.
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They're all parallel, no crossover. If the speakons don't work you may not have the right connection on the cable plug. Those are four pole. According to the diagram 2+2- are connected to the driver, 1+1- are pass through, so you can use a four conductor cable to send both the low and high frequency signals from a breakout panel on the amp rack to the subs and then just a two conductor cable from there to the mains.
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It's possible they have passives, but I'd open them up to be sure of it.
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Are these powered? I assume not, as powered don't specify impedance. If that's the case you can't link the tops and subs, you have to separately power them, using an electronic crossover to send the lows to the subs amp, the rest to the tops amp. Also, be aware the the way you see 99 out of 100 bands set up their PA, with the mains above the subs. is incorrect. The mains should be pole mounted to the front left and front right, the subs placed together, preferably next to a wall to one side.
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Not necessarily pointless, especially if you have a particularly anemic amp where even 3dB helps. But what you're going to get is not all that much, and the difference between 130w and 200w isn't even 3dB.
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Leaving cab in the car in freezing weather
Bill Fitzmaurice replied to ReeV0's topic in Amps and Cabs
My outside thermometer currently reads 2F/-17C. What's just as significant is that my indoor humidity meter reads 26%. I have a large humidifier running all the time, using on average two liters of water a day, otherwise it would be closer to 10%, a by-product of heating the house. Where the potential for moisture damage is concerned that's far more likely if you live in the tropics or near the ocean than if you live in a temperate climate. -
Leaving cab in the car in freezing weather
Bill Fitzmaurice replied to ReeV0's topic in Amps and Cabs
Condensation is more of a concern with amps. I've never run into a condensation problem with speakers, in temperatures that you never experience in the UK. -
Leaving cab in the car in freezing weather
Bill Fitzmaurice replied to ReeV0's topic in Amps and Cabs
Cold won't bother it, but thermal shock can. Let it get as warm as possible before using it. -
Doesn't it have a volume knob? Either reduces the voltage drive to the speaker, giving the same result. The only reason to use a power soak is when you have a valve amp that you want to over drive the power section on while keeping the volume low.
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That's a common misconception. The load on the output valves isn't the speaker, it's the output transformer. The impedance of the output transformer primary winding is a constant, therefore the speaker load doesn't affect current delivery. With direct coupled SS amps as the load goes down current goes up, because as the name infers the speaker load is directly coupled to the output devices. Using voltage to measure sensitivity doesn't favor a lower impedance speaker. For that matter one cannot measure sensitivity with anything other than a voltage source. One cannot hook up a meter to the amp output to read the amp power output, as no such meter exists. One may only read the voltage output. If one could read the power output it would render the sensitivity spec useless, because power output is different at every frequency. Voltage is used not only because it can be measured but also because it's constant no matter what the frequency.
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Speakers aren't driven by watts, they're driven by volts. While an 8 ohm speaker sensitivity is usually quantified as dB/1 watt/1 meter that's incorrect, because the amp power isn't a constant. It varies with the actual impedance load, which varies with frequency. If amplifiers were constant power devices every frequency would be at a different level. But they're not. An amp does provide constant voltage output at every frequency, no matter what the speaker impedance is at that frequency. Therefore the correct way to state sensitivity with an 8 ohm speaker is dB/2.83v/1 meter. If you add another identical speaker the amp output voltage remains the same, while sensitivity of the pair goes up 6dB compared to just the one. As to why sensitivity goes up by 6dB, output is dependent on cone displacement. When you double the displacement, which is cone area multiplied by excursion, you get a 6dB increase in output. In the case of adding a second identical speaker while maintaining the same voltage the cone area doubles, excursion remains the same for both, therefore displacement doubles and output goes up by 6dB.
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If you run two identical 8 ohm cabs (or whatever impedance) voltage sensitivity goes up by 6dB compared to one. That's what's responsible for the increase in output, not power. Power goes up because the halved impedance load doubles the current draw, but that's really anecdotal. You don't run two cabs to get more power out of the amp, you run them to take advantage of the sensitivity increase.
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Making that error impossible is reason enough why only Speakons should be used.
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That's fine. The trouble with your tech's advice is what does one do it they have a 2.67 ohm load as in the case of the OP? How does one match that exactly with the tap choices being 2 and 4 ohms? You can't. You may use either, though, and neither will bother the amp in the slightest. Amps aren't designed to operate into a precise impedance load because there's no such thing as a precise impedance load.