agedhorse

Yes, I deal with this sort of thing often enough that these warnings (including warnings in the newer owner's manuals) are entirely justified.

That's EXACTLY what is being discussed, and what the OP's situation involved.

External DI's are almost never used to boost the signal level from instrument level to line level. In fact, since the numbers you posted above are incorrect, let's clarify what happens with a typical direct box. For bass guitar: Mic levels are typically in the range of .01V to .1V Instrument levels are typically in the range of .1V to 1V Speaker levels are typically in the range of 10V to 50V A typical DI drops instrument level signal down to mic level (approx. -20dB) and for a DI with a speaker level input, drops the level down to mic level (approx. -40dB). This is (often but not always) done by the use of an step-down audio transformer (in combination with an input pad in the case of a speaker level signal). The transformer also galvanically isolates the signal source from the destination. One very important thing to make note of... in the case of any amplifier that is configured in bridge mode (either externally or as an internal topological design element which is how many class D power amps operate), taking the output from a speaker out is a bad idea because neither the + or - terminals of the speaker output are ground referenced. When connected to a DI, the pin 1 connection becomes tied with the speaker - and results in shorting 1/2 of the output bridge. Also, the resulting fault current (which can be as high as 30 amps on some newer amps) will flow through pin 1, through the snake and into the console's grounding system. Since this grounding system is not designed for high currents, catastrophic damage can result. If this is an expensive console, somebody is going to be unhappy.

The balanced output clips at +2dB peak (-1dBu RMS) maximum, not enough for driving a power amp to rated output in the real world. You will need +4dBu (minimum) plus at least 6dB of headroom to make up for losses relative to real world implementation.

No sir, class D has nothing whatsoever to do with the power supply. It has to do with the topology of the power amp only.

Except that the DI out will not be able to drive the amp to rated output unless it's full line level (ie. nominal +4dBu)

If you understood that this amp is NOT rated for a 4 ohm load in bridge mode, you wouldn't recommend something dangerous to the health of the amp. Bad advice.

With that amp, which I know very well, you are much better off running dual mono.

Except that most bass speakers fail from exceeding their mechanical limits not their thermal limits. The mechanical limits of a speaker can be as low as 1/2 the thermal rating, and when you exceed the mechanical limits you cumulatively cause damage to the suspension components and reduce their lifespan. Also, mechanical power handling decreases as frequency falls below ~100Hz on most speakers. Generally, when you match the amplifier power (in RMS metrics) with the speaker rating (in RMS metrics) you will be reasonably well matched. This is a rule of thumb that’s holds up pretty well in the real world IME.

Line level serial effects loops are often used for different purposes depending on the player. For example, some player use it for connecting a LINE LEVEL processor (compressor, eq) in series with the signal path, some players use it to connect to the send jack to drive a line level input, and some use the effects return as a power amp input, bypassing the onboard preamp. Then again, some players have no need for any of the above and don't use it at all.

Yes, due to the architecture, the DI output (post) is also post master volume. Yes, you can operate the amp without a speaker attached.

The company behind the product itself is an older, established firm. Indie was a brand that this company manufactured, the guitars were actually quite high quality.

Speaking of fur and such, going back decades acousticians used to refer to sound absorption or anti-reflection as "dead cats". If you needed to reduce the reverb time, you would stick some more "dead cats" on the walls. Not a very PC way to describe it though.

What about that "fur" thing that's draped on the back of your couch (chesterfield?) That looks like it will work...

In between plotting out CAD drawings. No more touring shows (or even local live shows) these days, so this is about as close to "the road" as it's going to get for the foreseeable future.

Actually, if you add 6dB of bass boost, you reduce the power handling by a factor of 4 because 6dB of power increase is 4x the power and 2x the voltage.

Yes, I am familiar with the brand and somewhat familiar with the amp. For what you paid, I think you got a heck of a deal.

You have received in depth answers to your questions on both TB and here... never mind.

This is accurate as far as transients are concerned, but ignores the fact that as you limit the peak amplitude, this allows for an increase in average power. For example, a reduction of 3dB of transients allows for a 3dB increase in average power. The ear perceives average power as loudness. This is one reason why tube amps appear to sound louder than their power might suggest, and also one reason why compression is so useful. With an increase in average power, the risk to the speaker transitions from mechanical to thermal assuming there is an effective HPF involved.

Yes.

Then why did you bother asking this question if you already knew the answer you wanted to believe? There’s a lot to learn from the answers and comments that were made my members here and on TB, it appears you have missed the essence of this information.

IF the cabinet tuning resulted in the same curve shape (translated to filter terms this would be Q and slope) than the red trace has the potential to provide better performance with both tuned to slightly under critically damped. Now the elephant in the room is what the relative sensitivities are between those two drivers (which would be the gain term of the filter equation). Is the red driver significantly lower sensitivity than the green driver by chance?

Have you looked at the comprehensive answers and information given to you over at your same thread at TB???

Kind of yes and no. Whenever the conduction angle of each side of the push-pull pair is greater than 180 degrees, as some low level of signal one half will be sourcing current while the other half will be sinking current throughout the full waveform, and technically that's class A. BUT, often the distortion can be worse because the handoff from the positive to negative half may not have the identical curve shape so the distortion can actually increase where these curves overlap and under this condition it's possible for class B (if the ends of the curves just meet) can have "better" (lower) distortion characteristics. This is something that Doug Self did a lot of research on maybe 20-25 years ago. The challenge is that the bias point at 100Hz may be different than at 10kHz, therefore a happy medium must be arrived at, usually that ends up slightly over biased at low frequencies for adequate bias at higher frequencies. In practice though, this is of no consequence.

Proper class B has almost no crossover distortion, but the challenge is to keep the bias conduction angle the same across the entire audio spectrum. At higher audio frequencies, sometimes additional bias is necessary to insure no crossover distortion which leads to more than enough bias at lower audio frequencies. This is an example of why often a single bias value is not adequate, and by biasing slightly into class AB at DC (and lower audio frequencies) to be sure that the operation at higher audio frequencies is adequate for at least class B operation.