Bill Fitzmaurice

Correct. In effect they work like a compressor, taming transient peaks that otherwise might cause the tweeter to fail. In extreme cases of overpowering they'll blow, turning them into fuses, although that's not their intended purpose. Those extreme cases are usually the result of using distortion effects, which increase the high frequency power content well beyond what most bulbs or tweeters can handle.

Wadding, more properly referred to as damping, serves two purposes. One is to reduce internal reflections in the cab, which cause peaks and valleys in response. How much will give the best result varies from cab to cab, with between one and two inches usually being good. The other purpose is to lessen midbass boom, which takes more material. In sealed cabs with high Q drivers, which have a tendency for boomy response, the cab might be fully filled. In extreme cases it may be not only filled but also compressed. Well designed ported cabs don't use high Q drivers, so they usually don't boom and don't require filling the cab to tame it. Of course not all ported cabs are well designed, so more than an inch or two of damping could be beneficial. A ported cab would never be stuffed and compressed, as that would mess with the cab tuning and could kill the low frequency output. How damping affects response and impedance can be software modeled by changing the Qa value. 100 is a bare cab, 50 is lined, 10 is filled, 5 is filled and compressed. It's an approximate result, as different materials have different indexes of absorption. It also is only accurate to roughly 2 to 3 octaves above the box frequency, as are all the results with speaker modeling software. The only reason to not use any damping is cost. 🙄

It makes no difference. The connection to the floor which gives boundary loading isn't mechanical, it's acoustical.

Amp manufacturers, certainly those who don't sell all tube amps, won't tell you that. To some extent one can get some of that tube response by over-driving a tube in the pre-amp, but it won't come close to an over-driven tube output stage. It's not just the tone and response that's different, it's also the perceived volume created by compression. That perception is the reason for the never ending 'tube watts' debate.

Most recordings since the late 60s were direct to the board, because the speakers of the day were so poor. To the extent that amps were used in the studio it was as monitors. James Jamerson was known for using an Ampeg B15, but he almost always went direct, using the same Motown DI direct box now sold by Acme Audio. https://reverb.com/item/4394324-acme-audio-motown-d-i-wb-3-direct-input-box?bk=eyJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJmZDdmYTI4OC1lODRkLTRkOTktYTI4NS1kZmU3ZmRkODA1ZjYiLCJpYXQiOjE2NzY4OTk1ODAsInVzZXJfaWQiOiIiLCJzZXNzaW9uX2lkIjoiOWYzOTNiMWMtOGM3ZS00NmI4LTg4ZjgtMjgyMjBkZDQ4MDJiIiwiY29va2llX2lkIjoiZDI5ZDI5N2QtYjIzNS00NWQ3LWE4NDAtMDA2NTFmYjdiMjc0IiwicHJvZHVjdF9pZCI6IjQzOTQzMjQiLCJzb3VyY2UiOiJOT05FIn0.7kZRDnlmhcQeqDRlfrndRM4mKyYWa2Gu9Wg-jhwje7A

Vintage sound doesn't come from a pre-amp tube. It comes from a power tube output section, which between the natural compression imparted by them and the output transformer imparts response that can only be more or less duplicated with amp emulation DSP. Between 1/2 and 2x the speaker thermal rating. Knowing that low price amp specs can't be trusted I'd avoid those.

No, you can't. What you can hear when playing tones below roughly 30Hz is their harmonics. Even if the source is a tone generator that only produces sine wave fundamentals harmonics are still there, created by the speaker. If it's a square wave generator harmonics are there in spades, as what makes a square wave square is harmonics. You may think that's the case, but electric bass produces mainly harmonics, especially below 100Hz. Classic reggae tone is primarily 2nd and 3rd harmonics. This is an RTA of a PBass playing an open A string. Most of the energy is in the harmonics. With lower notes there's even less fundamental and more harmonic content, and this is with the pure signal from the bass. The coloration imparted by the speaker results in less fundamental content.

Figuring out what's going on with just ones ears is daunting, even if you know the physics. That's where measurements come in. That used to be an expensive proposition, but not today. Download this to your phone: https://play.google.com/store/apps/details?id=com.dom.audioanalyzer Set it to Sound Analyzer, 1/3 octave bands, C weighting, Slow weighting. Ideally you want to input a pink noise source into your amp. You can download a pink noise loop to your PC. With that you can see in real time the effect of moving the cab. The phone needs to be placed where your ears would normally be with respect to the speaker, and not moved during the testing. That's critical, as even a slight change in the mic placement will alter the result. http://ethanwiner.com/believe.html

All speakers are below the frequency where the baffle is one wavelength across. Above that they shift to directional. As you keep going higher the radiation angle keeps shrinking. Since a wavelength at 100Hz is 3.4 meters it takes a large cluster of subs to be directional. It depends on how far the backline is from the subs. But by and large if you're getting a lot of output from the subs on the stage it's mostly below the frequencies that your backline cab is producing, the fault of a sound man who doesn't know what he's doing. IME the #1 fault in concert sound today is sound men pushing the bass at lower frequencies and higher levels than they should. I had the pleasure of seeing 'Tower of Power' tonight and the sound man actually got it right. It's a good thing, if he'd turned fabulous funk bass into a boomy unintelligible mess I'd have had no choice but to hogtie him and hijack the board.

Looking at a picture the port is so close to the rear of the cab that if that's happening it's minimal. As for the Hybrid Resonator, I don't know what it is. Possibly a dual chamber reflex, which would explain the port placement, and the description of what it does. Nonetheless for the space between the cab bottom and floor to act as an effective extension of the port it would have to be placed in the middle of the bottom.

In order to lose the coupling between the floor and cab the cab would have to be lifted at least 60cm off the floor. No bass was lost, it just seems that way because you're hearing mids and highs that you weren't before. That doesn't make any difference either. The port frequencies are lower than those from the cone, making the wavelengths longer, so the port would have to be even further from the floor to lose coupling, at least 150cm. If you're running with the same EQ on the stand as you did before that explains the mid content being more than what you want.

There's no such thing as enough power to drive it properly. There's only enough power to go as loud as you need to. That could be 100 watts, it could be one. How much is enough? The Ampeg B15 is 30 watts. Horses for courses.

The more watts the louder, yes, but running either an amp or speakers to their limit isn't a good idea, for their longevity or that of your ears. Compare this to a car. Let's say the speedometer goes to 240 KPH and the tach goes to 7,000 RPM. That doesn't mean you should be driving 240 KPH at 7,000 RPM. You can, but probably not for long. The car has that capability so that it will run for ten years or more at 120 KPH at 2500 RPM. How many watts is enough? Between one half and twice the speaker thermal rating. One half is usually enough to drive a speaker to its mechanical limit. Twice gives you more amp headroom, which gives cleaner tone. If your amp can only deliver half the speaker's mechanical limit that's at best -3dB from the speaker's maximum output. -3dB is audible, but just. As for linearity of power versus loudness, it isn't. It's a logarithmic relationship. That's why I said the first 100 watts are the most significant. That gets the average speaker output to the vicinity of 115dB at one meter. 115dB for extended periods will cause hearing loss. (Just ask Pete Townshend. You'll have to speak loudly.) Luckily we tend not to stand 1 meter from our cabs, but still, it's louder than we usually play at. A more reasonable 109dB takes only 25 watts. Where the next 75 watts come in is headroom, again so you're not running the amp at it's limit. Going beyond 100 watts, if for some silly reason you want it twice as loud 200 watts won't do it. That only gets you to 118dB. Twice as loud as 115dB is 125dB. That requires 1,000 watts. Not that it matters, at that level you'll go deaf in short order. The only advantage to having 1,000 watts over 100 watts is that it gives you 10dB additional amp headroom, so that you won't clip it on hard transients. But with a realistic 25 watt average draw you only need 250 watts for 10dB of headroom. The last factor comes down to specsmanship, the fudging of data by marketing departments. The higher the stated power output the more likely the marketing department is writing cheques that the engineering department can't cover. Some companies are famed for doing this, TC and Bugera being two. Some have a well earned reputation for honesty, Ampeg being one. If only there was a comprehensive independent testing source to separate the wheat from the chaff, but there isn't. This is where cost versus claims comes in. If the price makes it seem to be too good to be true it probably isn't.

No, and for that matter chances are you may never put the full 800 watts into it. The first 100 watts are the most significant, and in most cases you won't put much more than that into it, other than as short transient peaks.

The 'ideal' size for the 3015 is 3 cu ft net tuned to 50Hz. 'Ideal', because you can go larger or smaller with the box size and the tuning, depending on what your priorities are. Commercial cabs tend to go smaller, sometimes a lot smaller, as their #1 priority is sales, and the current consumer trend is for smaller and lighter. My 3015 is in a 5.6 cu ft horn loaded enclosure, as my personal priority is maximum performance. I also have a ported design for the 3015 that's 'only' 2.5 cu ft, for those who's priority is more ease of transport. Every speaker makes compromises. What experience teaches you is where you can afford to compromise and where you should not.

Yep. Sealed cabs and older ported cabs have a natural roll off below roughly 80Hz. We compensated for that with the bass tone control, which started boosting around 200Hz, reaching maximum boost around 60Hz. When you do that with a modern ported cab that rolls off at 50Hz or lower it changes the character of the sound, from what we think of as vintage to what we think of as modern. All we have to do to get that vintage tone is to use EQ to roll off the low end below 80Hz, emulating sealed and higher tuned ported cabs. What's interesting is that if we'd had cabs that went flat to 50Hz or lower back in the day 'vintage' might have sounded quite different. Or not. Bass cabs didn't go very low, but neither did the speakers that most people listened to music with. The evolution of electric bass tone went hand in hand with the evolution of consumer speaker capabilities. One major complaint of younger drivers of BMW, and I'm sure other makes as well, is the audio systems won't wake the dead two counties away with pounding bass. That's because the low frequency knee is around 60Hz with full bass EQ boost. I've got no complaint with the sound of my Bimmer, as the only music I listen to is Classic Rock. 😁

None do below 100Hz. It's actually the Kappalite 3015. Xmax is 5.9mm, which is longer than average. It will take 450w mechanical through most of its range. The 3015LF goes lower, and will take 450w mechanical at every frequency, but lacks mids. That's OK if you use it with a midrange driver, or for a pure reggae all bottom no top tone. Otherwise it's not at all versatile. To get that you'd need to use two twelves.

One thing to look for in an amp is an EQ section that allows you to boost at 100 Hz and cut at 50Hz. This will allow you to closely duplicate with a ported Barefaced the tone of the sealed SVT.

I use a lightweight 1x12. It's not small, though. I have a lightweight 1x15 as well, also not small. I hardly use it, for outdoor gigs only. Indoors the 1x12 is plenty.

Louder yes, but it's best to have the bass feed in the monitors high passed at 120 to 160 Hz. Side fills too. The backline provides all the low end either you or your band mates need on stage. It's only the directional frequencies, above 120 Hz, that need to be be spread around better. Part of the problem with spreading cabs and running full range into monitors and side fills is that it not only provides more mids and highs that you want but it also provides more lows that in most cases you don't. The case where you might need lows is on a huge stage outdoors. Feel free to run full range at Wembley. 😉

FWIW don't split cabs. When you do it creates hot and cold zones in the lows, AKA 'Power Alley'. If you want to be heard on the other side of the stage aim one cab at yourself, the other across the stage. That aims directional mids and highs so they can be heard, without creating a power alley. This explains. It references PA subs, but applies to bass cabs as well: https://www.prosoundweb.com/the-power-alley-discussion-solutions-to-the-troubling-interaction-of-subwoofers/

Where tone is concerned reggae isn't low end strong in the 40-60Hz range, it's midbass strong in the 60-90Hz range. That's because the benchmark reggae cab, the SVT 810, isn't low end strong, it's midbass strong. It's also loud. The reason it's loud is the eight drivers, which have a combined cone displacement of 1300cc. If you want to get SVT volume without the SVT size and weight the way to do it is with high displacement drivers. The highest displacement drivers available in commercial cabs are those used by Barefaced. Four Barefaced tens or two Barefaced twelves will go almost as loud as an SVT 810.

That's where the driver specs come in. The ideal tuning for contemporary high quality fifteens will be closer to 45 Hz, but as the saying goes they don't make them like they used to, so 53 Hz may be best for that driver. This and five minutes is all you need. https://www.parts-express.com/Dayton-Audio-DATS-V3-Computer-Based-Audio-Component-Test-System-390-807?quantity=1

Having seen some real nightmares I never assume that anyone knew what they were doing without checking it for myself. 😉 By and large most fifteens work best with cab tuning of 45-50Hz. That can be confirmed from the cab dimensions alone.

A hole is a port. A hole with a tube or extension behind it is a ducted port. Over the decades the 'ducted' part of the name has been dropped from common usage. A hole is still technically a ducted port, with the duct length being the thickness of the panel it goes through. The longer the duct the smaller the port will be and the smaller the cab may be for a given tuning frequency. The smaller the port the higher the velocity of the air vibrating within it. With sufficient velocity you can hear that air mass vibrating, so there is a point where it can be too small. Your cab may be fine, it may not, which can be determined with the exact cab dimensions and the driver specs.