Bill Fitzmaurice

Blame Leo Fender. Good engineer, but a notorious skin flint. Telephone switchboard 1/4" jacks and plugs had been used for electric guitar leads probably from day one. When Leo came up with separate heads and cabs he used 1/4" because he had them on hand. In his defense there wasn't much to choose from, but still when Leo had a chance to save a buck he did. The same applied to his instruments. He didn't set out to build a better guitar, he set out to make a cheaper guitar, and the bolt on neck was how he did it. By the same token single coil pickups were cheaper than hum bucking, which were around since 1932. Fender was able to sell his guitars at 2/3 the price of Gibson. It was pure serendipity that they also sounded very good.

Obviously there are no glaring differences between those charts. Note the deep notch they all have at 90Hz. That's the cancellation caused by the distance from the cab baffle to the wall behind. There's another around 150Hz. That's probably from the distance between the mic and the floor.

I figured you meant 1 meter to the front. 1 meter to the back would push the baffle even further from the wall, lowering the cancellation frequency. When dealing with hi-fi or PA where you have separate subs and mains the subs should be placed close enough to the wall so that the cancellation frequency is above the sub passband, while the mains should be placed far enough from the wall so that the cancellation frequency is below their passband. You can't accomplish that when the mains are mounted above the subs. For that reason the only time one should do so is if there is no rear wall, which is to say outdoors.

That will result in a response cancellation notch centered around 80Hz. It wouldn't affect the comparison, they'd all suffer equally, but unless you're trying to reduce boomy response due to an 80Hz response peak you don't want a cab that far from the wall. I won't venture an opinion on which is which, knowing that driver size alone only affects off-axis response.

Pretty much. There is one factor that's almost entirely related to speaker size, that being midrange dispersion. The smaller the speaker the wider the dispersion angle. That's why midranges are smaller than woofers, and tweeters are smaller than midranges. But all else is determined by the Thiele/Small specs of the driver and the engineering of the cabinet.

The range of power usefulness is 4:1. With a 200w cab amps ratings of between 50 and 800 watts is appropriate. Frankly if you blow a bass cab it's entirely your fault, because it will severely distort long before it will blow.

A good 1x12 or 2x10 should suffice.

True. However, there's a benefit to testing with the same amp settings. Power doesn't define how loud a cab goes, voltage swing does. While power varies with the load impedance voltage swing does not. So if your intent is to see which cab will go louder with a given amp you test them with the same voltage input. Halving the voltage results in one-quarter the power. Also, in most cases otherwise with identical drivers save one is 8 ohm and the other is 4 ohm the 4 ohm driver actual impedance is usually more than half that of the 8 ohm driver. There are too many variables involved to truly know how much power the cab is actually being driven with. When you use voltage as the benchmark there are no variables. For this reason testing is never done with a specified power, as there's no way of knowing how much power is being applied. It's different at every frequency. Testing is always done with a specified voltage. When the result is called 1m/1w that's a calculated figure, and not a particularly accurate one. For instance, this charts the power into an 8 ohm speaker at 2.83v. How many watts? There's a thousand answers, one for every frequency.

You'll be surprised how loud 2.83v is at 2 meters. BTW, you can't accurately measure pink noise with a volt meter as it will bounce quite a bit. Get it close and leave the amp set at the same volume with each speaker. If you want to calibrate the result you'd do that with a 1kHz sine wave at 2.83v. Measuring at 45 degrees is simple, just rotate the cab.

First and foremost do the testing outdoors, well away from any buildings or walls, otherwise at least half the result will be from the room. Some years ago there was a much ballyhooed 'subwoofer shoot out' where the results were totally useless, as the room response dominated the results. Second, don't place cabs near each other. An unused cab acts as a bass trap. It's best to leave the mic in one spot and then place each cab in the same place one by one. The mic should be at least two meters out from the cab location, preferably more. 1m/1w is how the charts are shown but that's an extrapolated result. Danley Sound Labs, for instance, measures at 10 meters with 100 watts, which is the equivalent of 1m/1w. Finally, measure on axis and 45 degrees off-axis. Off-axis is where differences between various configurations will be most evident.

A more accurate statement is that it shouldn't be more than just tickled when you play your heaviest.

The reason why is that the output voltage of the Boss isn't high enough to cause the amp input to clip. None I can think of. The purpose of the indicator lamp is to tell you when the input level is too high, not when it's too low.

The only potential issue with lifting a cab by any method is some loss of boundary reinforcement from the floor, but it has to be a good meter or so before it becomes apparent, and then it's in the midbass that causes boom, so it can be an improvement. If this case is the one you're hauling your cab in using it as a stand is a good idea, as it also gives you a place to store it while playing.

Marshall and just about everyone else used Russian tubes for years, and it wasn't because they were cheap. Long after the West went to all solid state in their military electronics as well as everything else the Russians still used tubes. Between the lowered demand and the higher manufacturing costs in the West, due to environmental concerns, most Western sources closed down. The Russian tubes were actually high quality, from having to meet military specs. The main source of tubes today is China, for the usual reasons. The end of Russian tubes is likely in sight, thanks to Putin's folly in Ukraine.

The valve doesn't matter all that much. There are valve amps that are quite clean, Fender for instance, when they're not pushed into clipping. It's only when pushed into clipping that the difference between valve and SS becomes apparent. Instrument amps by and large sound bad when used for hi-fi, but that's mainly the fault of the highly colored response of the speakers and the preamp pre-shape.

Correct. 1+/- and 2+/- refer to amp channel 1 and amp channel 2, for use with a bi-amped system. Since your speaker is mono only1+/1- are used.

Oops. But you know what I meant. 😄

It's acoustical engineering fact. Stereo only exists where the ear can directionally locate the source, which is roughly below 100Hz. This being the case low frequency content on recordings has been summed to mono since the 1970s. Home cinemas can get away with one sub for that reason, but they still work better with at least two, for smoothing of the in-room response. Home theater subs are. Most PA subs are not, as for the most part the size, and expense, is prohibitive. But it doesn't matter There's very little low B string fundamental content, it's mostly harmonics. The same is true of the E. That's why few bass cabs go flat below even 50Hz. It's not needed. But PA subs do go flat, usually to 35Hz or so, and that's the main reason why bass can sound so overblown when the guy in the FOH doesn't know what bass is supposed to sound like. It's also why using an FRFR PA cab won't give the same tone as what a large PA will, unless you also have a 35Hz capable sub.

If it was common with them it would have been reported long ago. An internal fault is always a possibility.

With passives and even some actives you always get noise when you take your hands off the strings. Most of the time it isn't much, but when you have a dodgy power situation it can be a lot. Chances are it's not the amp at fault, it's the dimmer, although some amps have less power line noise rejection than others.

To some extent that's correct. Part and parcel of tube sound is power supply sag. The reason why a tube pre doesn't give the same result as power tubes is that pre tubes don't draw enough current to give the same degree of power supply sag as power tubes. A rectifier tube will help, but still won't give the same result as tube rectification of a power tube voltage rail. The popular consensus is that Fender ruined their amps when they made the change from a rectifier tube to solid state diodes. From a technical standpoint SS diodes work better than tube, but technically better doesn't always sound better. Mesa and others addressed this with dual rectifier amps, allowing the user to choose either tube or SS rectifiers.

What makes a tube amp sound like a tube amp is the natural soft knee compression of the power tubes. Using a compressor, preferably in the effects loop, will get a SS amp close.

In the '60s Fender ruled the US and Canada. If you could afford Fender that's what you had. Traynor was one of the second tier brands, an alternate to Fender for the less well heeled. Traynor was essentially a Fender knock off and sounded just as good, or bad in the case of electric bass. Sunn was the bass rig of choice when it came along.

That depends on the speaker. If it has a tweeter and you use it put the mic close to but not directly on the tweeter axis. If not put it close to but not directly on the axis of one of the woofers.

I don't know. If the cab is always vertical there's no need for it.