agedhorse

Read the manual and learn how it works before you damage something.

I think you will find that the smaller the box and the greater the expectations, the more difficult and expensive the project will be. The advantage of buying already well designed speakers is that the while you are paying for the designer's experience and knowledge, you are also indirectly paying for a number of prototype builds that may have been much poorer and "scrap worthy" than the finished product. Respectfully, I understand the desire to build your own, but you are comparing to a very high quality and expensive speaker. As a professional designer, I know how hard it is to get results like that without churning through 6 or 8 prototypes, and the cost of custom drivers also. Stock drivers are not intended for this type of product, which is why custom drivers are used. My coworker is the engineer who designed the entire KRK monitor line, I know how much work that was to extract that much performance in such a small, reasonably cost effective package.

I disagree, an accident or momentary lapse of good judgement will put the 4 ohm cabinet at greater risk. This doesn’t mean you CAN’T damage the 8 ohm cabinet but it will be much harder to do.

No, this is not true. Overpowering is by far the greatest cause of speaker failure. Power (watts) is absolutely correct in describing power handling, once you understand what it means. In this case, the “myth” that a 4 ohm cabinet will draw more power from the amp is absolutely correct for virtually all solid state amps as they are turned up. To the OP’s question, the 8 ohm 210 is a MUCH better and safer choice with no downside and many upsides.

Start here with the owner'smanual: https://manualsbrain.com/en/manuals/1111847/

The MOSFET preaamp version appears to be based around Ampeg products, I'll let you guys determine the basis of the tube preamp model...

You make some good points, yes we do stand on the shoulders of those earlier designers but while we are doing so, most of us are careful (respectful) not to stomp on their heads. I have talked with other designers (including one who was responsible for some of the Peavey class D designs) about the ethics of (and the differences between) learning from other designers and simply copying. Most designers have surprisingly high morals and take pride in developing new approaches while refining long standing circuits to improve performance and reliability. There's general agreement among designers that the customer will accept a "cheap copy" if the price is low enough. The pedal world is a good example of blatant copying (including PCBs). If there's enough of this, it will affect those companies that are currently bringing new approaches and new ideas to the players, ultimately the investment required to develop innovative new products will dry up and many new ideas simply won't make it to market.

Cosmetic, materials, layout plus feature set, even down to the fonts and legend on the back panel. If it wasn't intentional, it's an unbelievable coincidence... The Benz is actually a play on the word "bins", which was the term used here in the states to describe bass cabinets... bass bins, which comes from the fact that Genz Benz originally stated as a pro audio cabinet and rack company. I started out designing pro audio products for Jeff, then we branched out to bass cabinets and later amplifiers. The Genz part is obviously from Jeff's last name, and was also a nickname. What are bass bins? The term 'bass bin' was used primarily in pro-sound before the advent of sub woofers to denote the cabs used to handle the lowest frequencies, down to 40Hz or so.Sep 6, 2012 (from Google)

Adjustable input sensitivity isn't going to matter with the Avalon, it's MOL is +30dBu which will drive every power amp I have ever seen with loads of headroom to spare.

For that console, mic level will probably be more appropriate.

Do you have the TS parameters for the drivers used in the cabinet, or did you assume that they were stock drivers (which they likely are not, even if they look like it)

First, I am assuming that you man ShuttleMax 9.2 since there was not a 6.2 model in the Shuttlemax series. If it's a Shuttle 6.2, let me know and I will get you a copy of the correct manual. It depends on what you are trying to do. Line level is fine IF the console that you will be feeding is capable of handling line level (most pro consoles will have no problem), but if not you can switch to mic level (which is about 20dB lower) The controls only affect the DI when switched to post-eq mode. I have attached a copy of the owner's manual, there is all the info you need about how the DI section works. ShuttleMax 9.2 Owners manual.pdf

That's a pretty early build, before they started using ICEpower modules. You are probably going to have to find somebody qualified to reverse-engineer the power supply to determine what's really needed to be reliable. So far, you have succeeded in discovering a couple of ways it doesn't work... Does anybody know how many of these amps might have been built? This may explain why there are no spare parts available.

I have designed all kinds of products over my career, mostly pro audio and bass products, but some acoustic and electric guitar products too. This includes both high end touring electronics/speakers as well as lower end electronics/speakers (including for some popular brands/models). I first look at the requirements, both performance and cost, and then look to see what components are already on the market that I might be able to use or easily adapt into the enclosure that the product will need. I will also look at my historical designs to see if I have already designed a driver that might be suitable. I really don't like reinventing the wheel, especially at the higher end where the transducer engineers have spent a fair amount of time and money on. That said, I probably put more energy into the lesser models because I NEED to squeeze out the most performance possible for the least cost. This is true in all product lines actually. I find it more challenging to get the maximum performance out of the minimum cost, that's what separates the experienced engineers from the onanists. In the middle, giving up a dB or two of performance may not matter as much but at the low end every dB counts, and may be the difference in a viable product and one that's not. At the very high end, there's a LOT more effort placed on pattern control, the evenness of the response at the edge of the pattern, distortion, power compression (thermal and electromagnetic), and also structural since the cabinets may end up over your heads.

Yup, insignificant heating issues.

Yes, the air gap will reduce the enclosure heating effects somewhat which is why I keep mentioning worst case.

My calculations show that with 25 degrees C ambient, a 31cm x 31cm x 31cm wood box with nominal 12mm thickness, the final temperature after "forever" (called the asymptotic limit) will be 33 degrees C with an 8 degrees C total temperature rise. This is about what I would expect worst case, pretty much trivial. Here's one handy enclosure calculator, there are several. These sorts of formulas are also used in the heating and air conditioning industry too, the walls will have a thermal resistance, and if playing in the sun there will also be heat gain due to radiation. https://www.powerstream.com/temperature-rise-in-an-electronics-enclosure.htm

There's not much heat involved, the average dissipation is less than 50 watts worst case. Not going to be a problem at <50 watts of dissipation, it would take DAYS to raise the temperature 10 degrees C above ambient.

The amount of heat in the speaker being discussed is insignificant in the big picture

I only have a couple of saddle mounting systems left for those amps. Yes, be VERY careful when "home brewing" any hardware for an amp, I have seen too long screws ruin an amp beyond economical repair (aside from being dangerous).

Yes, it makes perfect sense IMO.

My experience and testing suggests that it's very dependent on the preamp and preamp pedal. There are a good number of pedals that have no issues driving power amps to rated output, the real issue is a shortage of specifications that provide the definitive answer. For example the TwoNotes revolt preamp's MOL is +11dBu (from their specs) and it operates from a standard 12V DC power supply.

Designers certainly sit down with these graphs when developing amps and speakers. They really aren’t intended for end users, especially because of the misunderstanding of the correlation between the graphs and how this translates to end results.

If you can’t understand the specs, than you either need to have somebody help you, by lucky or buy products designed to work together. It’s no different than taking gigs where you need to sight read, if you can’t do it, don’t take the gig and don’t criticize those who do.

Since I spent much of my career in the pro audio industry, there are a lot of misconceptions going around. First, it’s acceptable to power an amp at 2x the RMS rating of a speaker provided there’s is minimal clipping or OD/distortion components in the signal. As soon as distortion is added, no matter where in the signal path, this recommendation changes and the power handling of the speaker and amp (in RMS metrics) should be pretty similar, and for heavier distortion, and heavy compression, the speakers should be capable of greater power handling than the amp provides (by ~50% if you follow the guidelines of some driver manufacturers including JBL). This also assumes that a proper HPF is also used. Crown’s recommendation is being taken out of context when quoted for bass guitar amplification.