Bill Fitzmaurice

By the same token no matter what the signal a highly colored speaker will highly influence the result. This is particularly of interest with respect to vintage sound, as the tone of the electric bass was very much defined by the shortcomings of the available speakers of the day, and they weren't very good.

They key to minimizing feedback from drum mics is to place them as close as possible, ideally with rim mounts. Of course that means using more of them. Overheads are for picking up cymbals.

TLAH Pro uses eights.  I didn't create a ten inch loaded version as when you get that large it's more practical to stack smaller single or dual woofer cabs. All of the DR, Jack and OmniTop designs have that ability, and being horn loaded have much higher sensitivity.

1 hour ago, warwickhunt said:

 

Indeed but it is essentially 3 other musicians who are preprogramed to think that the only place for bass bins is in 'that' wrong place!    

There are only two reasons for them thinking that. One is 'That's how everyone does it'. The other is 'It's the only way we know how to do it'. Neither is a valid reason to keep doing it. That's why one person should be in charge of PA, that being the person who is the most knowledgeable.

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.

2 hours ago, warwickhunt said:

  For the last year I've tried to convince the band that 2 bass bins directly under the tops (15" RCF) isn't the best place but I'm battling 3 other opinions with all of their ingrained habits and it isn't easy.  

  

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.

37 minutes ago, Phil Starr said:

That could have just been boundary reinforcement. Placing a sub back against a wall means the sound is all going forwards reinforcing the sound levels.

+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.

1 hour ago, SimonK said:

I totally accept that with modern drivers two of the same cab will, on average, be better than mixing cabs, but the TE example I've posted strikes me as potentially an exception because here someone has actually sat down and designed three different sized speakers to work together?

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. 🤪

36 minutes ago, BassmanPaul said:

Two cabinets always sound better, fuller than just one.

 

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.

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A bit of digging into old TE catalogues and around the interweb tells me that the top cab - 2103x - with both 2x5 and 2x10 drivers is voiced to work specifically with a 1x15 inch cab

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.

1 hour ago, Stub Mandrel said:

 

Sorry Bill, for once you are wrong. For a DC load VA = Watts, but for AC if the load is capacitative or inductive the actual wattage is less than the VA figure by the power factor.

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. 

1 hour ago, Stub Mandrel said:

 Orange rate the power consumption of the 500W bass terror at 690 VA (Volt Amps are close to Watts).

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.

16 minutes ago, Phil Starr said:

 PA was still largely about getting as much sound as possible out of speakers that wouldn't handle huge amounts of power so multiple cheap drivers was the rule of the day.

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.