Bill Fitzmaurice

That will only put undue strain on your 2x15. Get a proper PA, because the lack of definition lies in the midrange and high frequency quality of the PA, not the lows.

I have serious doubts that he knows what he's doing. For instance: The two bass vents act as side handles. They are positioned to let cooling air flow to the speaker. On stage they send low frequency sideways which doesn’t muddle the sound you hear. The output of ports is 100% omni-directional. For that matter from a cab of that size the direct output from the cone is omni-directional below roughly 250Hz. 🤔 There are a number of other issues with his claims, but this one alone is enough to convince me that you should probably avoid them.

They'll work, but they're not matched. There's a difference. In any event mid cancellation on the horizontal plane happens when either drivers or cabs are placed horizontally. The cure is easy, don't do that.

That will cause low frequency cancellations. Put one cab on the floor, aimed at the drummer, for him to hear. Put the other on top of it aimed at you for you to hear.

A full crossover really isn't called for, as this isn't a sub/midbass arrangement as you have with PA. In order to make best use of it I'd set the sub low pass between 200 and 500Hz, whatever sounds best. There won't be any phase issues between the sub and the 112s with the sub only working that high, it's only above 800Hz or so where phase interactions between different drivers operating in the same pass band can cause more harm than good.

The line out will drive a sub, and as the sub should have its own volume control so long as the line out from your amp is post-volume control it will control both. However, for the sub to be worthwhile it would have to be at the very least a 115, if not a 118, with at least twice the power as your ABM.

You may have seen somewhere that the inherently low damping factor of tube amps works better with sealed cabs, but it's not true. This explains why damping factor is a non-issue: www.cartchunk.org/audiotopics/DampingFactor.pdf

Not knowing the exact topology of the cab I really can't say, other than it might be a dual chamber reflex. Many examples of dual chamber reflex can be found on line.

By your description it may be a dual chamber reflex. If that's the case the first mention I recall of it was in a book by David Weems, circa 1980.

No problem, since it's fan cooled the only potential issue, heatsink/vent orientation, doesn't exist.

Ampeg may seem a big deal, but in the scale of things bass amps and speakers are small potatoes compared to the PA gear that's the meat and potatoes of LOUD. My guess is that Yamaha finally gave up on trying to crack the American market for amps (do they sell in Europe of the UK?) and probably picked up Ampeg for a song, so now they can get into that market through the side door. It will be interesting to see if they sink any money into R&D.

The BP102 has very poor midrange response. I only use them in subs or with midrange drivers. If you can't match the existing drivers you need to replace all of them, but only after using speaker modeling software to confirm if they'll do what you want to do in your cab.

There's no point. You may think that there's an advantage to the proverbial 'getting all the watts out of my amp', but there isn't. If you did have a 4 ohm cab versus 8 ohms the greatest potential difference in maximum output would be 2dB, which is inconsequential. That's best case, with an amp that's rated no more than 1/4 the cab power rating. With a less skewed amp to speaker power rating, where the maximum output is likely limited by the driver excursion, there would be no difference. The speaker outs are already connected within the amp. That cable would accomplish nothing.

I'll be the first to point out that if a 410 isn't loud enough you should be looking at a better PA, not adding another cab. If you're having trouble hearing yourself elevate and/or tilt your cab back. You don't have hearing receptors on your calves.

The link is to instrument cables, where shielding is required. The sales pitch is pure Monster, and just as silly. Not that there aren't factors to consider with instrument cables, mainly capacitance when used with passives. But low capacitance cable is both common and inexpensive. I found on their site shielded speaker cables, predictably aimed at the home theater/audiofool market. FWIW no one has ever come up with a speaker wire that works any better than lamp cord. Quite the contrary, expensive/complicated constructions tend to work worse. As it this case with all cable crooks what's completely lacking on their site is definitive data to back up their claims, because there is none.

Too simplistically. You can achieve the exact same results with neo or ceramic. For that matter you can with AlNico. The AlNico magnet JBL D130 of 1949 had a more powerful magnet than most drivers made today. The advantage to neo is light weight, the disadvantage is cost. That being the case if you use neo you're not going to use it in an inexpensive driver, and if you're making an expensive driver it will probably be low Q. As for tone, you can overdo the magnet strength. Beyond a certain point lower Q results in reduced low frequency response.

The problem when you use the term damping instead of Q is it causes others to confuse it with where the term damping is rightfully used. Even using the term in association with Q can only lead to confusion, so the preferred explanation of what Q does is control. For instance: https://www.eminence.com/support/understanding-loudspeaker-data/

There are two primary uses for the term damping with respect to speakers and amps. With speakers it's the characteristics of the absorptive lining or filling of the cab, if any. With amps it's as part of the term 'damping factor'. Neither applies in this case, where the appropriate term would be Q, probably Qts, possibly Qes. Neo versus ceramic doesn't even enter the conversation, as Q is independent of the magnet material. There may be an anecdotal relationship between Q and magnet material. Neo is a much more expensive material than ceramic, while low Q drivers tend to be more expensive than high Q drivers, so neo drivers tend to be low Q. But that's by no means a hard and fast rule.

Engineers don't use subjective terms like 'tight', which mean different things to different users. Marketeers do.

The difference is that instrument cables don't use large enough gauge wire to handle the current that an amp delivers to a speaker.

Passives, I assume. Most of the noise issues with passives have to do with their high output impedance, compounded with the relatively low input impedance of valve amps. Back when I ran passives straight into valves my solution was to never back off on the volume control. The issue went away when I installed my first on-board pre.

A jack is the part that a plug is inserted into. The 1/4" phone jack and plug were invented for use on telephone switchboards.

There are a dozen or so specs that determine driver performance. The magnet material isn't one of them. For that matter neither is the thermal rating of the voice coil. Not by a transducer engineer or IMO a competent speaker designer. That's the kind of inaccurate generalization one might expect from a marketing department.

The drain wire is connected to the same terminal as the ground wire. BTW, 1/4" connectors are phone, not phono (RCA).

With a drain wire, like so: