Bill Fitzmaurice

+1. Some 90% of GB can be driven to from any other place in GB within ten hours. Some 95% of Canada cannot be driven to within ten hours from any other place in Canada. The province of Ontario alone is five times the size of Great Britain.

4 hours ago, matybigfro said:

I'd actually stumbled across your post before Bill while googling to try and find out about the APT-80, would fitting a BGH25-8 be an option in the 410TX (it's meant to be 700 watts program) and would that mean replacing the crossover with as per your design on that thread?

It would, the reason being that with the BGH-25-8 and the crossover I designed it works down to 2kHz, so you avoid the beaming issue with the woofers. The BGH25-8 also rolls off above 10kHz, where there's no useful content for electric bass. A 3.5kHz tweeter crossover makes perfect sense in a hi-fi speaker with a 6.5 or 8 inch woofer, but not in an electric bass cab.

BTW, if I was to go to the trouble of replacing the tweeter it wouldn't be with either the Peavey or Eminence APT-80. Neither go low enough to reach where the tens are beaming. This thread explains:

I found that, but it's next to worthless. You need a real data sheet, like this: https://eminence.com/collections/eminence-tweeters/products/apt_80#specifications

I can't find any real data on the Peavey Triflex to compare it with the APT-80. I found replacement diaphragms for the APT on Amazon and eBay, but that's the US sites.

It might look cool doing that, but the unplugged 115 will become a passive bass trap. 😲

Periodic cleaning of the jacks is a good idea.

20 minutes ago, Downunderwonder said:

Any sound person worthy of the title should recognize that effort and endeavour to EQ their PA to the room to save themselves the effort of tweaking everything in the mix.

Even at the top tier of touring sound I'd say 90% of FOH engineers don't know how to mix the bass. Most of those who do are also bass players and/or recording engineers. 

1 hour ago, Stub Mandrel said:

 

Bill was.

Yes, I was. Even at 'only' seven pages there's a lot of different topics in this thread. Someone who might have an interest in one of them has to wade through a lot of information he doesn't care about to find what he's after. If this thread gets much longer it's going to need a table of contents.

On 09/09/2023 at 03:59, Downunderwonder said:

The aim is that the player's monitor sounds like what he expects to hear out in the room. The identical signal is sent to FOH with the expectation they will treat the room EQ before messing about with the bass feed to make it fit.

So many people get it backasswards.

Yep. What those not in the business don't realize is that both amps and speakers spend a lot of time being Beta tested before they hit the shelves. It's done so that it sounds good out of the box with as little EQ adjustment as possible. The manufacturer of one speaker that I designed took close to a year of Beta testing with dozens of players just to dial in the crossover. 😲 It was worth it, it won numerous new speaker of the year awards, but still that's a lot of testing.

Using an FRFR you usually end up using a lot more EQ to get the sound you're after, which means it's not going to be a simple plug and play unless you have an modeling amp or accessory speaker emulating circuit. Think about that. You have an FRFR speaker and then you need an amp or accessory to make it sound like a speaker that's not FRFR. 🤥

For the cleanest sound set the output at full, the gain as high as necessary for the desired level.

Agreed, specific questions should be posted in individual threads, just as in the amps & cabs section.

True. But while the on-axis response of the 410 may be better the off-axis response of the 115 is better. Dispersion is inversely proportional to the width of the radiating surface, and you get comb filtering from a 410, you don't from a 115. Not only is mixing a 115 and 410 not a good idea, the 410 format is not a good idea. With the capabilities of today's ten inch drivers there's no question that even for high volume applications a pair of 210s vertically stacked is the modern benchmark.

Don't sell the PA. There will be times you can rent it out, with you at the helm of course. That puts money in your pocket, and gives you the opportunity to hone your PA skills hearing what it sounds like out front.

2 hours ago, Pirellithecat said:

  But still resistance as the baked in belief is that it's not possible to get "that" sound without driving the guitar amp/ cab.

That's quite likely if his amp is too big.

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Some of the guitar players here might be able to suggest how to make that noise with less volume.

A smaller amp. 50 watts into one twelve is sufficient.

4 hours ago, Pirellithecat said:

Any good way to stop this happening .....  or tips on how to tackle it? 

Insist that his amp be on a tilt back stand that aims the speakers at his head. If there's going to be suffering from his volume let him be the first to experience it. As for the ear plugs, if they're not buds to hear the monitor mix he's playing too loud. The backline should only be pushing the stage volume, not the room.
 

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All instruments in mix but only Vocals and Kick/Snare to FOH.

They should all be in the FOH, bass included. High pass the bass and keys, if any, so the only thing in the FOH from them is the higher directional frequencies that need to be there for even distribution across the room. Also try aiming your lower cab towards the drummer, so he can hear your mids.

0dB is the approximate threshold of hearing as was defined by Bell Labs when they invented the audio decibel, which is a tenth of a bel. Care to guess where bel came from? At the same time they quantified 1dB as the minimum difference that the average person could hear, but that varies from person to person and frequency to frequency. The threshold of pain also varies from person to person and frequency to frequency. Our hearing is most sensitive in the vicinity of 500 to 1kHz, both with respect to intensity and pain. In the midrange we might feel pain at only 115dB, in the bass it might be 140dB. Where hearing safety standards are concerned 'A' weighted metering is used, as it's most sensitive in the same region as our hearing.

It looks fine. Much ado is made about inductor orientation, but it's moot with that much spacing.

4 minutes ago, sandy_r said:

 it could be that all access is expected via the front, after build completion (removing drivers, of course).

That's SOP with monocoque construction.

If pressure on the back stops it I suspect the glue joint between the back and the brace has failed. A couple of screws would fix that.

Many amps do color the sound, via built in non-defeatable EQ known as pre-shaping. That was usually the case with valve amps, which could not be set to flat response. It's less common with SS, but even those in many cases have pre-shape, even if just by dint of high passing the signal at 30Hz or so. Speaker coloration is almost always present. The main effect of speaker modeling tools is to use EQ to emulate the inherent coloration of various speakers for playback through speakers that actually have flat response, Hi-Fi and high end PA.

Between amp and speaker coloration the practice of setting all the EQ knobs at noon to give flat response doesn't work. Not that you'd want it to, as flat response is as desirable as flat beer. At the very least boost in the low frequencies is a must, necessary to compensate for the response of the instrument, which isn't flat either.

4 hours ago, bremen said:

"digital" is such an abused word it just slides past me now. I have a pair of headphones branded "digital".

I remember in the 80s when CDs were introduced everything from receivers, tuners and amps to speakers and even wires were labeled as 'Digital Ready', giving the impression that you needed to upgrade to play CDs. The only change that had been made to the gear was the addition of the 'Digital Ready' sticker. 🤥

1 hour ago, Downunderwonder said:

 Double was the rule for older solid state

There are two considerations. First is the small signal response. In that case the halving of impedance results in twice the power delivery. But at full power you don't get twice the power delivery, as power supply sag at full power prevents that. This applies to almost all SS amps, no matter the class. Not that it matters all that much. As already touched on perceived loudness isn't linear with respect to power.

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250W into 4Ω and I hook it up an 8Ω cab, it will be pushing out circa 125W, maybe a tad more?

Quite a bit more, perhaps 150W. But that's at full power, which we very seldom use. Why? Because of another subject not yet touched on, the actual power handling capacity of the speakers. That's hardly ever what's listed, which is the thermal capacity. What really matters is the mechanical capacity, which tends to be half the thermal capacity or less. Power, whether it be that of the amp output or the speaker thermal limit, is insignificant. What we engineers concern ourselves with is the amp voltage swing and current capacity and the speaker excursion capacity.

The reason there are no truly digital amps where our needs are concerned is a speaker can't make use of a digital signal. Many amps have some type of A/D conversion of the input signal, which is amplified by pulse wave modulation that requires low pass filtering before the speaker can make use of it. That makes them quasi-digital. AFAIK PWM amps were called Class D because when invented in the 1950s it was the next available letter in the alphabet.

13 minutes ago, Smanth said:

and the speakon connector sayas 4 ohm min load.

 

 

Speakons are rated for amperage, not impedance. Amps are rated for impedance loads.

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would it be reasonable to expect the head to not add colour when used in this way

Any amp will put out a flat signal if the applied EQ gives a flat signal, be that the internal or external EQ or a combination of the two. But unless you have a method of measuring it you can't know.