Bill Fitzmaurice

Where it comes into play with respect to speakers has to do with the potential for damaging the amp. With sufficient phase shift between current and voltage the current and voltage can both be at a maximum. Combine that with low impedance and the result can be magic smoke.

Ask them what the speed of sound is. Every acoustical engineer, pro or amateur, knows that number as well as they know their own name, as it's the prime factor in calculating wavelengths. If they don't know that number and don't know what the importance of wavelengths is they don't get to offer an opinion. They may have one, but they should keep it to themselves.

If it's too close you'll know, by the feedback. Max Weinberg and his band were in town a while back, he had a sub set up maybe six feet to one side. When he played there was a constant droning feedback that drowned out the entire band. I mentioned it to the guy in the booth, he was too busy playing games on his phone to care. That's when I left.

+1. Against the wall is the equivalent of doubling the sub count, in a corner the equivalent of quadrupling it, compared to well out. It also eliminates boundary cancellations that occur when not tight to a wall or corner. But 'adjacent to the drum kit' is a no go. Not only will you have low frequency feedback into the drum mics but you'll also have acoustical coupling of the sub and drums that creates another feedback loop.

The issue with respect to speakers is that impedance isn't a constant figure, it varies with frequency. Volts x amps= watts, but since amps vary with impedance which varies with frequency power also varies across the spectrum. Even if you have the gear required to simultaneously measure both voltage and current across the audio bandwidth the result looks like this, a 2.83v signal into an 8 ohm speaker. That's nominally 1 watt, but as the chart shows there are only four frequencies out of fifteen thousand where it's actually 1 watt.

Perhaps that's what was claimed, but I'd need to see proof before I believed it. I've seen too many examples where the sum total of the engineering involved in speakers supposedly designed to work together was to make the cabinet corners interlock. Having designed more than a few commercial cabs I know from personal experience that far too often the design priorities in order of importance are profit margin, looks, and coming in a distant third, sound quality. For instance, in that Trace 2103x the fives, and preferably the tens as well, should be placed vertically, not spread apart as they are. I take one look at that configuration and think 'comb filtering'. If they didn't get the driver placement right I wouldn't trust them to have gotten anything else right.

Subs at the back of the stage won't feed back any worse than at the front as the output of subs is omnidirectional. Placing subs at the front, and for that matter more than a half meter from the wall, costs output and low frequency extension, so that should be avoided anyway. What matters in this case is the distance from the subs to the mics. But since subs cannot be directionally localized you can move them well over to one side or the other and the audience will never know the difference.

They never have. Way back when Fender put stickers that said 'Special Design' on the driver magnets. The only difference between them and off the shelf was the stickers. 🤪

Unless grossly mis-matched that's true. As a for instance a 410 plus 115 will almost always sound better than either on its own. But a pair of identical 410s is better. Maybe. If true the tens would be guitar drivers. But even then if not bi-amped with an electronic crossover the tens are seeing lows and the fifteen is seeing mids and highs that they shouldn't.

How drivers work is primarily defined by their Thiele/Small specs, not the magnet material. It's those specs you need to compare. However, in general it's easy finding Waldo than OEM driver specs. Where low frequency output is concerned the most important spec is excursion, xmax. If they're not very close you can have one cab comfortably cruising along while the other is distorting badly.

No comment on particular models, but what makes a mixer good for the studio is having as many output channels as you plan on recording with. That makes a two channel mixer that's adequate for the stage not so great for recording. But if you have a mixer with eight or more outputs sooner or later you'll find a use for them on stage.

The load presented by a speaker has capacitive and inductive components, but it is mainly resistive. Where speakers are concerned capacitance is minor. Voice coil inductance is significant in that it increases impedance, but that reduces current draw, so where power factor issues are concerned it's not an issue. There are instances where a crossover can cause problems with respect to power factor, dropping Z lower than DCR, resulting in what's referred to as a difficult load for an amp, but that's in hi-fi. I've never seen it in pro-sound.

Volts multiplied by amperes is the very definition of watts. 1/8 power is the benchmark for measuring long term continuous amp performance as that's -9dB from maximum, which is the minimum amount of headroom required to prevent clipping during transient peaks.

You may be able to use the existing box with a new baffle, which should leave room for a line of eights or tens plus a line of tweeters.

You always get twice the power when you double the current via halving the impedance while maintaining the same voltage swing. That's an immutable law of physics. What can happen with not only Class D but with every amp class is that there's power supply sag at full power into a lower impedance load, so the amp can't deliver twice the current while maintaining voltage swing. That's why the full power rating doesn't double with halved impedance load. At less than full power it does double.

The truth of the matter is that the benefits of column speakers were well known going back to the 1940s, the main one being vertical pattern control. They worked far better than point sources in reverberant spaces, like clubs and other large gathering places . Perhaps the most noteworthy installation of them was in St. Paul's of London circa 1950. They worked well there for some fifty years before being upgraded with modern line sources. The demise of the column speaker came for two reasons. Foremost was the lack of high frequency drivers, so they sounded dull compared to point sources that had high frequency drivers, like the Altec A7, which spawned hundreds of similar designs. But there was also the fact that most users had no idea why they had good vertical pattern control, or for that matter what vertical pattern control was, let alone what comb filtering was and why placing PA cabs side by side was the worst possible configuration. It didn't help when trapezoid array cabs were introduced. They were supposed to make horizontal dispersion better, instead they made it worse. No matter, they were what buyers wanted, and manufacturers were more than happy to supply them.

I know, but that's not how it works. Cone excursion, which creates the sound waves we hear, isn't created by power, it's created by voltage swing. The voltage output of an amp is a constant into any impedance load. When you have one driver/speaker driven with a given voltage the cone will travel 'x' millimeters. When you add a second identical driver/speaker parallel wired the amp will deliver that same given voltage into both, so both cones will travel 'x' millimeters. This results in a doubling of the cone displacement. When you do that sensitivity goes up by 6dB, as does maximum SPL. Power only enters the equation insofar as the halving of the impedance load with the doubling of drivers/speakers parallel wired also doubles the current draw on the amp. Doubling current while maintaining constant voltage doubles power, but it's not that doubling of power that gives higher sensitivity or maximum SPL, it's the doubling of the cone area while maintaining constant excursion via constant voltage.

Nope, because then you lose the advantage of sensitivity and vertical pattern control of the column. The right way would be to use at least four tweeters arrayed vertically to one side of the woofers, in this fashion.

The main difference it that the old style 12" loaded columns usually didn't have tweeters, so they weren't much good above 3kHz. Columns equipped with tweeters would have been far superior to the woofer plus HF horn cabs that replaced them, but AFAIK no one ever made one.

You can't leave half a 210 at home when you only need a 110.

They're quite good. They don't have the thermal capacity of the Deltalites but they have what really matters, xmax. At 5.2mm the 2012 has more output capability than the 2512 with 4.9mm. I run a 2012 in my personal JackLite 12 cab and it does the job nicely, while weighing almost nothing.

Doubling the cab count gets you 6dB of additional sensitivity/maximum output, which is the equivalent of increasing power by a factor of four. The higher power output from the amp when the impedance load is halved doesn't result in the increased output, it's just a byproduct of the process. Putting the second cab atop the first makes the mids and highs more easily heard, which also increases the perceived loudness. If that's not enough then a better amp can be tried. While the 500w rating of the neo Rumble 112 is so much fluff it's loaded with a Basslite 2012, which has a real world mechanical capacity of 150w. A pair of them could handle a lot more amp than the TC the OP has.

Meters always measure DC resistance, which is on average 20% lower than impedance. It takes a much more complicated tool to measure impedance.

The reason for using an FRFR speaker is to remove speaker coloration from the equation, not to have overall flat response. Then the only tone shaping is done by the amp. In theory if you provide that tone shaped signal to the PA via a DI, which must be either in the amp post EQ or driven by the amp output, the sound in the PA will be the same as that from the stage. In theory, because it requires that the EQ at the console be left flat, that the PA subs aren't boosted in level, and that the in room response be the same in the audience as it is on stage. It's one of those ideas that seems to make sense but very seldom proves to actually work, because sound engineers are seldom if ever content to leave things alone. You may think that your tone is your business, but they tend to think that it's theirs.

Sadly you didn't get my drift. 😁