Bill Fitzmaurice

The leads me to believe a bad ground on the mains, or massive interference from either florescent lighting ballasts or refrigeration compressors.

Power conditioners don't do much, if anything. The best method of power conditioning is to rectify the AC to DC, then remove any ripple with filtering capacitors. The thing is that's what your amp power supply does. Besides, noise isn't necessarily on the AC line. It might be airborne RFI or EMI. You mention having a complicated set up. That could be introducing ground loop noise. First things first, run the amp with nothing plugged in. If there's no noise that rules out the AC mains. Then just the bass. If there's no noise that rules out RFI and EMI. Then add the effects. If noise results it's probably a ground loop. There's also the possibility of a bad ground on the AC mains. It's a good idea to carry a plug in mains tester to be sure it's not dodgy.

Make a cardboard box the same size as the cab to test it.

It's an issue, but not one necessarily caused by the pot. The total voltage gain from pickup to speaker starts with the pre in your bass and ends with the output stage of the amp, with every gain and EQ stage in the chain making its own contribution. Google 'gain staging'. That said, you've got the effect of the pot backwards. Assuming you have a linear pot wide open versus at half the attenuation at the halfway point is -3dB. That's audible, but just. It's not half volume, which is -10dB. A log taper pot at half is -10dB compared to at full. Therefore the linear pot goes louder earlier in its rotation, not later. Some amps did so on purpose, so that someone trying one in a shop would be impressed at how loud it got at, say, a setting of 3. They wouldn't have been able to realize in a shop that anything past 4 didn't get any louder. 🙄

Most assuredly it does not. Power output depends on a number of factors, starting with the voltage output and frequency response of the bass, ending with the actual impedance of the speakers, which isn't a constant. It varies with frequency. This is a plot of the power output of an amp across the frequency spectrum into a typical 8 ohm twelve in a ported enclosure, driven with 28.3v, which is nominally 100 watts. There's nothing linear about it. This, BTW, is why loudspeaker engineers don't deal in watts. We deal in volts, which are a constant into any impedance load.

I didn't miss it.

That wouldn't be caused by the different driver sizes but by different phase responses. At frequencies where they differ at or close to 180 degrees apart they cancel. This scenario is one reason why well engineered systems never use different drivers in the same passband. Comb filtering is a related effect. It's when wave fronts from multiple sources meet at or near 180 degrees apart causing cancellation notches that alternately occur and disappear as one goes across the sound field. The primary cause is placing drivers side by side. The easiest cure is don't place drivers side by side. If you must do so the fix is to low pass one driver, or one side of a 4x,6x or 8x cab, so that they only work in tandem in the lows where comb filtering doesn't occur, and not in the mids and highs where it does. It's a simple inexpensive fix, known as an x.1 alignment, that's been used for at least fifty years by PA designers. AFAIK the only bass cabs that use it are Barefaced. What happened there was you had a boundary reflection sourced low frequency cancellation zone on stage, where you were close to boundaries. Out in the audience away from those boundaries you don't have those cancellations, so the lows are louder there. If being where you were also put the cab on axis with your ears as it always should be the mids and highs would have been louder and more clear as well. The cure is to do your sound check listening out in the audience, adjusting both volume and EQ accordingly. Whatever that results in on stage you live with.

That's why you can't hear it. Why do you think the monitors are tilted upward?

Seems like a good idea, but our hearing isn't linear with respect to power. It's logarithmic, requiring ten times the power to sound twice as loud. That's why logarithmic taper pots are used for volume controls. They may not be linear, but they sound linear.

In that case...there's Powersoft if you've won the lottery. Otherwise just search. Just be sure it's full range, not a low passed sub amp. Sub amps are very inexpensive, as they don't need low THD specs and other attributes because they don't operate where they're an issue. IMO a better option is to make the cab an airhead, with an integrated space for a rack mount amp that are abundant.

Not that I know of. Those I'm familiar with don't have a pre-amp and tone controls that are suitable. You'd still need that in a separate package or pedal.

Even worse, multiple sources playing low frequencies may cancel each other. Besides, what you don't need from monitors is lows. You need mids and highs, especially if your backline isn't aimed at your ears and the mids and highs from it are passing you by below the belt.

You can find third party sources for manuals for most amps. Google ' *** amplifier manual'.

It depends on where the lamp is wired to the circuit. Clipping can take place at every stage of amplification, from the input to the output. The manual should say. In general minimal clipping takes place when the master is on full, with the pre volume low.

The only people with any interest in your rig are other bass players. 😉

Aside from an old spare for emergency use, which of course I've never had a need for, I've never had more than one amp. You'd think I'd have a shed full of speakers too, but I don't. I've never had more than two on hand, most of the time only one. I've never owned more than one bass at a time either. The one I have now I made 25 years ago. I'm comfortable with what I have.

He may, he may not. When I do my initial sound check in a smaller room without major PA support I do it from out on the dance floor, adjusting my volume and tone for the best result there. Whatever that ends up sounding like on stage I live with.

Functionally a send and an active DI should be essentially the same. They may differ in whether they're pre or post EQ. The amp block diagram would reveal that.

At the very least either lift the cab or tilt it back to aim the drivers as close as possible to your ears. One of the reasons why the 8x10 gets so much love is its height allows you to hear the mids and highs.

Google 'boundary sourced low frequency cancellation'. You get it when you're close to boundaries. It goes away when you move away from them.

That. The cone area of a five inch cone, Sd, is around 100 square cm. Four of them is around 400 square cm. An average twelve is 530 square cm. Just as significant is the excursion limit, xmax, which combines with Sd to give displacement, Vd. Vd defines how loud a driver may go. An average five inch Vd is 50cc, making it 200cc for four. An average twelve Vd is 300cc, a high end twelve Vd is 500cc. There are a number of other factors which impact how low a five can go. They can go as low as larger drivers, but to do so they sacrifice sensitivity, which means less output per watt of input. I'm a big fan of fives myself, in the right context, which IME is as a midrange driver used in conjunction with a larger woofer.

You need sufficient gauge to handle the current without overheating and not cause voltage drop. At 1 meter it doesn't take much. Wire gauges are typically used in the same locales that use inches and feet, mm where they use metric, for the same reason. This is a must read if you don't know anything about cables. It's aimed mainly at the hi-fi crowd, as they tend to be more easily scammed by cable mountebanks than professional musicians, but the physics still apply. http://www.roger-russell.com/wire/wire.htm

I have no issue with buying rather than making your own, even though it's a ten minute job. But at least buy something that's reasonably priced, twenty quid tops. The reliability factor is determined by the quality of the connectors. Those I linked from Blue Aran are as good as it gets.

That's an insane price for a one meter cable. As for all the claims they make, they're piffle, the entire lot. A pair of these, along with a meter of zip cord from a local hardware store, is all you need. https://www.bluearan.co.uk/index.php?id=NEUNL4FX Just be sure to get Neutrik, not an imitation. The knock-offs have been known to cause problems. You're a bass player. You're supposed to be the smart one in the band. 🙄

When you've got four identical woofers sharing the same airspace you're not going to get a significant difference in response from each pair even if you were to bi-amp them, let alone dual amp.