Bill Fitzmaurice

So we'll call that 30L tuned to 65 Hz. Two that will work well are the Celestion TF1230S and Lavoce WAF 122.50.

And the port? If there is one.

Precise measurements of the cab are the first step.

While it may sound bass heavy the reality of reggae is it's midbass heavy. This is an RTA of The Wailers, through a no holds barred million quid system, taken in the FOH, the best seat in the house. Most of the energy is between 60 and 180Hz.

2 hours ago, Lozz196 said:

I’ve not owned any but have played through a good few, with usually the only set up time being a line check but always been able to adjust eq to quickly get a good sound. They seem to have a presence that some other brands don’t imo, it’s difficult to describe it, maybe a hardness/solidity to the sound. Really helps with on stage sounds and hearing yourself.

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I had a pair of GK 112 cabs (a long time ago, they may have been the 112MBEs). Unimpressive, didn't go very loud and got very harsh very quickly. Moved them on for a pair of Berg AE112s which were far, far better.

These quite different experiences point out that it's not the brand that matters, it's the specific cab. One might as well be asking 'Any experience with Toyota?' That depends. Toyota Aygo? Or Toyota Mirai?

Not 4x but 2x at any rate. Indoors the bass bins get boundary reinforcement, outdoors they do not. That translates to no less than 6dB less output to the audience outdoors. Doubling the cab count realizes 6dB additional output.

Hire, with a sound man. In terms of what you need for outdoors versus indoors it's at least twice the kit.

That would be my guess.

Ask your girlfriend if size matters. 😲

Where speakers are concerned cone area doesn't, cone displacement does. But box size is the other way around. All else being equal (though it never is) the larger the box the lower it will go.

What this boils down to is that without a lot of information that speaker manufacturers don't provide you can't know how any two cabs will compare. If I was to venture a guess I'd say the Mesa is more capable than a single Big Ben.

Any that have a gain and a master volume.

It also only fully worked at lower volumes, the effect being reduced as the volume control was raised.

5 hours ago, funkydoug said:

Is it fair to say that in Bill’s scenario of a series-parallel 410 vs a parallel 210, the drivers in the 410 will each be further away from their excursion limits and so there may be more low end response at medium volume and above?

Axial frequency response of the 210 and 410 will be almost identical. It would favor the 410 with enough voltage for the 210 to suffer from power compression both thermal and mechanical, but that's a different question than what the OP asked.

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Another factor may be that (if stood vertically) the 210 will probably disperse mids wider than the 410, so depending on stage positioning it may sound louder.

True, the mids will sound louder off-axis.
 

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3dB from the extra piwer into 4 rather than 8 ohms.

3dB from extra area.

 

Not quite. In the OPs scenario the voltage to each cab is the same. In the case of the 210 the displacement (T/S spec Vd) is doubled. When you double displacement with the same voltage to each driver, as is the case with parallel wiring, you get a 6dB increase in sensitivity. Doubling Vd again with the 410 would get you another 6dB with parallel wiring, but with series/parallel wiring the voltage to the individual drivers is halved, which reduces sensitivity by 6dB for a net zero gain over the 210. To realize the 6dB higher maximum SPL from the 410 compared to the 210 you'd have to turn up the volume to double the voltage output, which then results in all four drivers receiving the same voltage as those in the 210.

The takeaway here is that it's not the power or cone area that counts. It's the voltage and the driver displacement.

OK, so if the same driver is used, and the same box volume and tuning per driver is used, with parallel wiring the 2x10 will be 6dB louder than the 1x10. If the 4x10 is parallel wired it will be 6dB louder than the 2x10. However, chances are the 4x10 can't be parallel wired, because the impedance load would be too low for the amp to handle. It would likely be wired series/parallel. In that case it would be the same as the 2x10. The 4x10 can go 6dB louder than the 2x10, but only by turning up the volume. And all the conditions must be met. If any or all of them aren't then the calculation doesn't work.

1 hour ago, agedhorse said:

We must also remember that there’s a lot of incorrect and terrible advice given through YouTube and other such platforms. 

It's getting worse. ChatGPT is really bad, because what it posts comes from searching sources on line. When the search turns up bad information it passes it on without peer review. 😒

3 hours ago, TimR said:

 

There are many ways of inducing current without voltage. Current comes before voltage as the first current was measured in a moving wire in a magnetic field. Your bass pickups induce a current with no voltage. 

If there's no voltage there's no signal, nor current. The strings vibrating in the magnetic field of the pickups induce both current and voltage. You can't have the one without the other except with a theoretical superconductor.

1 hour ago, Beer of the Bass said:

 

Most models of WEM Dominator were open backed combos, I suspect there's a reason why almost nobody has made an open backed combo for bass since then.

The last I used was a '59 Bassman, for guitar. I can hardly imagine one on bass, as it only took ten watts to hit xmax with four Jensen P10Qs in an open back cab. But Carol Kaye did most of her early studio work through a Fender Super Reverb, which was similar. That's because she was originally a studio guitar player. One day the scheduled bass player for the session didn't show up, so she plugged a bass into her guitar amp. And it's why you can hear a touch of reverb on the bass in many Beach Boys recordings. But that was in the studio, where not a lot of volume was required.

And that's why Mesa Dual Rectifier amps give you the choice. 😉

7 hours ago, Woody1957 said:

I get your point, but don't forget the bass players on this forum who have years of pro/semi pro experience, but without the so called technical knowledge that have witnessed otherwise....

We're not saying that you didn't witness what you witnessed. We're saying the cause of what you witnessed isn't what you think it was. And why would you? Without technical training one cannot be expected to make a diagnosis of why a driver failed. The value of threads like this one is it allows those without technical training to learn from those who do. But one can only lead a horse to water. From there on what happens is up to the horse. 

3 hours ago, Chienmortbb said:

As I understand is, Sag in power supplies adds to the natural compression of valve amps that may or may not continue in the pre-amp stages and is certainly true of the output stages.

True. One reason why earlier Fender amps are preferred is they have valve rectifiers, which have better sag characteristics than those from the mid 60s and later that have solid state diode bridges. That additional bit of sag contributes to the soft knee compression of those amps.

You usually get double the power at small signal levels. In most cases you don't get it at full power due to power supply sag.

2 hours ago, Obrienp said:

I am sure that speaker technology has moved on leaps and bounds since my youth but I still wouldn’t feel safe running an amp that had a higher rating than the cab, even though I would never have the master anywhere near max. I feel nervous enough running my BF Two10 with amps that have the same RMS rating. The LFSys Monza gives me a comfortable feeling because, at 600 watts AES, it has twice the rating of any of my amps @ 8 ohms.

 

Tell me why I am wrong.

You're not wrong. It's perfectly safe to use an amp rated at even ten times the speaker rating so long as you employ the volume control. It's perfectly safe to use an amp rated at one tenth the speaker rating as well, even if you crank it into hard clipping, so long as you don't have a tweeter. The myth of underpowering came about decades ago after JBL published a document on how amplifier clipping could damage 'the high frequency components of their loudspeaker systems high frequency devices'. It probably took three re-tellings of the tale, if not less, before 'clipping can damage high frequency components' morphed into 'clipping kills speakers'. Engineers like myself have been countering that notion ever since, but it's like a never ending game of whack a mole. The truth of the matter is succinctly summed up in this quote:

There's no such thing as "underpowering" a loudspeaker. The loudspeakers really don't care about the shape of the waveform. A square wave is not by itself a killer of tweeters, woofers, etc. Well over 90% of the power put into a loudspeaker driver turns into heat, whether the waveform is square or not. Overpowering (thermal damage from too much power) and over-excursion (excessive cone travel, typically from low frequency energy) are what damage loudspeakers.

Bob Lee
Applications Engineer, Tech Services Group QSC Audio
Secretary, Audio Engineering Society

Rebuttal is welcome from anyone claiming to have Bob Lee's level of expertise.

Porting would give you a bit better result, but not enough to make it worthwhile IMO, the box is too small. You'd need to go up to at least 50 liters not including the space taken up by the port.

A critically damped sealed box, which is to say Qtc of 0.5, is going to be very large. But as it's a sealed speaker it's not going to have high sensitivity at low frequencies, which explains why they're seldom used even in home theater.

🤫 Once again:

Clipped wave forms are harmful for tweeters, as they can increase the power in the high frequencies well above what what the tweeter normally receives. But no matter how hard the clipping the power will never exceed what the woofer normally receives in the lows. That's the science, and the science always works, whether you understand it or not.

As to blowing a 100w speaker with a 50w amp, for instance, yes, you can. Most 50w amps can deliver transients of 6dB above rated power, and that's means 200 watts. Is the amp clipping? Sure. Does the clipping cause damage? No. Over powering does.

BTW, a distortion pedal creates clipping, far more clipping than any amp is capable of creating. If clipped wave forms hurt woofers distortion pedals would not exist. Neither would synthesizers.

1 hour ago, Woody1957 said:

Absolutely spot on! Running a high wattage amp on low volume is far better than running a much smaller wattage amp on full volume. 

What you need is an amp with head room and lots of it when playing bass otherwise the speakers will burn out, no matter how good or powerful they are.

That's the myth of underpowering. It's already been discussed in this thread with full explanation why it's not true. 😒