Bill Fitzmaurice

You need a cable with 1/4" on one end and Speakon on the other. What's labeled as Direct Output goes to a mixing console, not a speaker. Read the manuals. If you don't have them do a search to find them. BTW, you're in the wrong forum. This is the PA section. 😒

A perfect example of why I stopped going there 13 years ago. It's like watching the Gallaudet University Marching Band, led by Stevie Wonder as the Drum Major. 🤥

Normally I'd agree there, but...the SP212 isobaric configuration means that while it has two twelves it only has the output of a one twelve. A proper 212 will give the OP what he needs, save the SP212 for those gigs where it's enough on its own.

A few items of disagreement. First off, he loaded that cab with replacement Celestions, so what the frequency response is one cannot say. Second, most of the power with electric bass is in the 2nd and 3rd harmonics, so when you play a 41 Hz open E what's mainly there is 82 and 123 Hz. By and large a speaker f3 of 50 Hz is sufficient, even for drop tuning. The SVT 810 f3 is 58 Hz. And lastly where hearing yourself is concerned that's mainly in the upper midbass through the midrange, roughly 200 Hz to 2kHz. As for "In terms of the angled / stacked speaker cabs, I’d have to disagree in my experience. The only times I’ve done that I’ve hated the sound - too harsh and right behind my head." when you aim the cab at your head rather than your calves you hear what the audience hears. If you don't like what you hear neither will they. The EQ should be set so that it sounds good on the speaker axis, not 30 degrees or more off axis. To remove the room from the equation I always walk out onto the dance floor for sound check, adjusting the EQ so that it sounds good there. If that results in less than optimal tone on stage I live with it, I'm playing for their enjoyment, not my own.

If this hasn't been a problem in the past then it wasn't your gear, it was the room, although a 4x10 arrangement doesn't help. You'd be better served with a pair of 2x10, stacked vertical, to get the upper drivers closer to ear level. At the very least your 4x10 should be tilted back and/or elevated, otherwise the directional mids that are the source of clarity are passing by you unheard.

They are.

More than a few DIY experimenters have turned that hobby into a lucrative profession. Included in that list: James Lansing, Paul Klipsch, Edgar Villchur, Henry Kloss, Conrad Sundholm, Thomas Danley and Alex Claber, and if I may, myself. All of got into speaker design because they were dissatisfied with what was available commercially and thought they could come up with something better. Audio design in general, and speaker design in particular, has always been advanced by the work of amateurs, unimpeded by corporate politics. Villchur's example is perhaps the best. He had a Masters degree in Art History. He got into audio as a radio repairman while in the Army in WWII. That piqued his interest in audio, which he followed up on after the war. When he came up with the idea for the acoustic suspension speaker he shopped it to all the major players. They all said the same thing, that if his idea had any merit that their own engineers would have already done it. That was circa 1950. Undaunted, Villchur built a prototype of his new speaker out of a plywood box. The dimensions of the face of the box were taken from a picture frame that he had hanging in his house. His wife, Rosemary sewed the pattern for the flexible surround out of mattress ticking. After proving his concept to himself, if not others, he and his student, Henry Kloss, proceeded to create their own company, Acoustic Research, in 1954. In 1966 AR’s loudspeaker sales represented almost one-third of the entire market. Not bad for a couple of tinkerers.

As one who does both commercial and DIY designs I have to disagree. One major advantage to DIY is being able to build designs that are labor intensive without concern for the cost of the labor. There's a reason why high end outfits like Danley Sound Labs get top dollar/quid for their products, and it's not just the cost of the components, it's also the cost of the labor to build them. A DIY build of a sophisticated design can easily match the performance of a high end speaker costing $5k at a fifth that price or less. Where commercial has the advantage of economy of scale is in the low to midrange price range, but even there DIY can still be the better route. You can buy a simple ported or vented box or you can build one for the same price but loaded with premium drivers, whereas buying a commercial one with premium drivers would raise the cost considerably. Now that's not to say that all DIY designs are gems by any means, I see cringe worthy junk all the time. But to be fair I see plenty of cringe worthy commercial junk too. Maybe not in the $5k range but certainly in the $500 range. And lest I forget...well, I did actually...DIY doesn't have expenses for marketing and distribution, office staff, accountants, lawyers, offices and factories, the guys on the loading dock...it's a long list that all contribute to the price you pay.

Zero. 😮 http://hornresp.net/ While it's called hornresp it will do horns, transmission lines, and direct radiators both sealed and ported. https://xsim.software.informer.com/ The only catch is you need Z and FRD files, but those are available for most drivers. Cost of the software is no issue. Learning how to use it is the hard part. Where going active is concerned there are full DSP plate amps at reasonable cost. Even if you go DIY with the amp the cost of DSP to go with it is about 10% of what it was 20 years ago. Not that I'd recommend trying to design your own for a one off build, the time it takes to acquire the skills required ranges from months for simple designs to years for complex designs. But there's no shortage of plans available from those who have done the work.

'Tis puzzlement for sure. If they have the chops to design and build good bass cabs they have the chops to design and build good PA cabs. On the flip side: The same absolutely applies to bass cabs.

You'll get the best results with four round ports 8cm diameter 15cm long. The rattles indicate insufficient panel to panel bracing.

To paraphrase Disraeli there are lies, there are damned lies, and there are specifications. 😮 No eight inch driver can take 650 watts continuous mechanically. No eight inch driver in a direct radiating enclosure can produce 126dB continuous. This is an example of the marketing department writing a cheque that the engineering department can't cover. Yes, most companies play the same game, but that doesn't make it any less dishonest. 🤥

Damping absorbs midrange frequencies that will otherwise reflect back to the cone at various angles of phase, causing response peaks and valleys. The back is the critical place to apply it, but for best results all the surfaces should be covered. It may not make a major difference, but it's so inexpensive there's no reason to not do so.

That's one option, but you don't need 50 meters. You should be able able to find the same polyester batting in a useful size at fabric shops, it's used for pillows and furniture upholstery.

Indispensable.