Bill Fitzmaurice

Watch this. All of it if you've got time, but what's most pertinent to this discussion starts at the 3:00 mark.

It's mostly confirmation bias. If you think a speaker will sound a particular way it will. Seeing an aluminum cone the natural assumption is that it will have a brighter sound than pulp, so it does. Going to an aluminum cone was a stroke of marketing genius on Hartke's part, as it separated them from the rest of the pack. The same applies to Markbass. There's nothing special about their drivers, but the yellow cones would lead one to think that they're somehow different. Confirmation bias in audio is pervasive; even those who you'd think would be immune to it are not. That's why good engineers never trust what they think they hear without confirming it with measurements. So are Hartke brighter? I don't know. I've never seen them measured. http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html

I bet he got it sorted, 12 years ago. 🤪

If it's not ported it's not going to give 'thunderous low-end performance' no matter what the advertising says. It still may suit you, but I'd try it before you buy it.

Good advice, in part because combo cabs tend to be undersized for portability. Amps keep getting smaller and smaller as that aspect of what physics allows is ever changing. The physics of how speakers work is chiseled in stone. Hoffman's Iron Law is just as true today as it was in 1970.

The Micro Stack had problems from day one mainly because it used a sealed cab. With one cab it got along OK, but with a second it couldn't handle the current demand when pushed hard, which with the low sensitivity of a sealed cab in the lows one pretty much had to do. Perhaps they've beefed it up since, but admitting they initially didn't get it right isn't typical corporate behavior.

A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't.

Or a Vox AC-30. 😉

You can buy one of Tom Hamilton's B15s for a mere $6k. https://reverb.com/item/68553915-tom-hamilton-s-aerosmith-ampeg-vintage-b-15-flip-top-bass-combo-amp-low-serial-number-early-1960s-6 Maybe it's not the same amp, but we often shared a stage in the 60s where we'd use his B15 and my Bassman. His 30 watt B15 was louder than my 50 watt 2x12 Bassman.

Even when accurate they're not worth much. Is a 500 watt amp ten times louder than a 50 watt amp? Nope. It's twice as loud, assuming they have identical transfer function. That's a long leap as well. Ask anyone with a 50 watt valve amp. 😉

Watts don't matter. If they did one wouldn't be able to gig with an Ampeg B15N. It's the total package that counts. I know that trying before you buy isn't easy, but it's still the best way to find what works for you, well worth investing a day or two.

Not one, other than cables and very rarely a string. When I was touring I had a spare amp, but never had to use it.

Amps don't send watts, they send volts. How much power is consumed by each driver is the product of said volts and current, current depends on the load impedance. In this case where each internal driver is 16 ohms if you add an 8 ohm cab half the power will be consumed by the extension, the other half is split between the two 16 ohm internal drivers. What the impedance switch on the amp does is an unknown, as there's no real explanation in the manual. It may be some sort of current or voltage limiter but that's pure speculation.

In 50 plus years of gigging the only spare pieces of kit I've ever used were cables and strings.

Thanks, but I made an error. The radiation angle of any source only shrinks to 180 degrees when the radiating plane is a wavelength in dimension. Since with direct radiating speakers the radiating plane is the baffle it's called the baffle step frequency. When it's smaller than a wavelength the sound will wrap around the cab, eventually going to 360 degrees as you go lower.

Some of us do. 🤥

Port radiation is omnidirectional, so the orientation doesn't matter. Scientifically speaking the radiation angle of any source only shrinks to 180 degrees when the radiating plane is less than a wavelength in dimension. At 100 Hz a wavelength is 3.43 meters. Yes, that means the cone radiation is omnidirectional at 100 Hz as well. That's why you can hear the lows standing behind a cab.

If you want to get rid of that dip it's easy enough, reduce Pe to 200w. It has nothing to do with the cabinet design, it just shows that the driver mechanical limit is lower than its thermal limit. That's not the least bit unusual. For that matter prior to roughly 20 years ago it was the rule rather than the exception. Want to know why vintage drivers were so poor with respect to bass? This is the maximum SPL of the ubiquitous Jensen C12N, which were in my '65 Bassman. If all you looked at was Pe then the 50w rating would seem adequate. Leo Fender certainly thought so. But with 1mm xmax it was mechanically limited to 5w at 60 Hz. 😲

It's not about increasing the power, it's about reducing the peaks in the response that are heard as distortion. Think of it as a fuzz box in reverse, making the tone sound clean at higher levels than it otherwise would. In the case of the OP it could well be that what seems to be speaker distortion is actually the amp hard clipping.

I don't know about GK but TC uses compression and other DSP tweaks to approximate valve transfer function with their RH amps, with power ratings of what they claim they sound like, as opposed to what they measure, leading to the 'TC Watts' scandal. The RH 750 is actually only 236 watts 'but it sounds like 750'. 🤔

Myth. A decibel is a decibel, no matter what the source. The primary reason why valves sound louder is the compression inherent with valves. Duplicate that compression, and all the rest that results in the amp transfer function, and SS amps of any class will sound the same as valves. Said compression and the rest takes place in both the pre-amp and power amp stages, so using the same pre-amp into different power amps will give different results. Valve compression results in easing into clipping, SS without an external compressor doesn't. That can result in very different results even when the power output and decibel levels are identical.

The dip on the maximum SPL chart is where xmax is reached. Since the 320 has considerably longer xmax it also has higher maximum SPL at those frequencies where xmax , rather than thermal power, is the limiting factor. You really don't want that dip in the 60-90 Hz range, as that's where the output demands of electric bass are the highest.

The speaker power rating is the maximum, not the minimum. For that matter the 600 watt rating is thermal. Chances are it may not handle anywhere near that before reaching its mechanical limit. I'd make sure that something's broken before trying to fix it.

+1. In the same box tuned to the same frequency the 12 PR 320 has the advantage in low frequency sensitivity (first chart) and maximum SPL (second chart).

The 320 has lower Fs and longer Xmax, better for the low end output.