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Query for Reconing Techs

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Line Array Quote  Post ReplyReply Direct Link To This Post Posted: 17 April 2025 at 9:39am
Originally posted by RoadRunnersDust RoadRunnersDust wrote:

if anything the peak capacity of modern equipment is far greater compared to its continuous capacity than ever before.

thank you for unwittingly proving my point.

amplifiers and music are both converging toward each other.  in the past music was dynamic but amplifiers were not able to take advantage of this.  today amplifiers are designed to exploit the fact that music has crest factor but the crest factor is getting crushed by loudness wars compressing everything. 

both are a good thing.

that is to say music and amps both started out in a vacuum but have become aware of each other and are gradually finding a common ground.

Originally posted by RoadRunnersDust RoadRunnersDust wrote:

Despite the opposite being generally true…

care to elaborate ?

Originally posted by RoadRunnersDust RoadRunnersDust wrote:

I’m amazed a “genius” like you managed to achieve that given how an FFT shows you spectral information and nothing about waveform shape nor *anything* in the time domain.

indeed being a genius helps.  but not as much as having multiple engineering degrees and having studied digital signal processing.  square wave, triangular wave etc. will have different harmonic profiles that will show up on FFT.

but that wasn't my point.  my point is that a square or triangle wave will break down into sinewaves most of which will get sent to the woofer, but the fundamental will be sent to the subwoofer, so as far as a subwoofer is concerned - it's a sinewave, regardless of what it started out with.

the question is whether this sinewave is continuous or intermittent ...



looks pretty continuous to me !  basically one gigantic 35 hz sinewave with some noise, distortion and other modulation added to it.  here is the track in question:

https://youtu.be/7U5QxwcWbv0?si=B2lP05Zf26fYRvJL

Originally posted by RoadRunnersDust RoadRunnersDust wrote:

And yet there is demonstrably greater dynamic range in the low end on in music produced for digital audio formats than there is found in any of the domestically available analogue mediums.

if it's the same genre of music i am sure it is true.  but most people who go to concerts are younger folks and don't listen to 50 year old music.

Originally posted by RoadRunnersDust RoadRunnersDust wrote:

The reason the upper registers have greater crest factor in music is and always has been due to natural energy distribution and the spectral sensitivity of the human ear. it has never been driven by the capability of the system, only the other way round.

it is due to the physical nature of sound.  lower frequencies are produced by physically larger phenomena that tend to move more slowly.  a twig that snaps when you step on it is a high frequency sound that is very short because the twig is light.  a wave crashing on a beach is a low frequency sound that is long because the wave is very heavy.

Originally posted by RoadRunnersDust RoadRunnersDust wrote:

And no, it can’t go down to zero since it is a ratio of RMS:Peak amplitude. It cannot go below 1. Surely a “genius” ought to understand that enough to not make such an inaccurate observation LOL

as a genius i have the benefit of understanding that crest factor can also be expressed in decibels in which case it can go to 0.


Edited by Line Array - 17 April 2025 at 9:43am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Line Array Quote  Post ReplyReply Direct Link To This Post Posted: 17 April 2025 at 10:20am
Originally posted by RoadRunnersDust RoadRunnersDust wrote:

Apparently you don’t understand “loudness” either. It is already well understood that if you want perceived loudness and depth for bass then the critical range for the ear is with the second harmonics.

i already regret making what will probably be my most broadband insulting comment i have made in 30 years of debating audio on the internet but here it comes ...

if 2nd harmonic determines the loudness of your bass then your system simply doesn't play the fundamental loud enough because it can't.

i am running close to 30 decibels of bass boost on Equalizer APO software into my Bose 700 headphones:




these headphones have their own DSP ( as well as pressure sensor based servo feedback like PowerSoft i-Pal ) in them and thus already have pretty accurate / deep bass, but i am throwing another 30 decibels of bass boost on top of that because i can ...

that's what gives me a somewhat uncomfortably loud bass in the 30 hz area which is what i like ...

now in the track i linked in my previous post cutting 35 hz on Equalizer APO sucks the life out of that track ...

it goes from having wicked deep borderline painful bass to ... well ... not having any bass.

why does this happen ?  because with my custom EQ curve the fundamental was LOUD ENOUGH to carry the track.

of course if your subs begin to roll off at 50 hz and the fundamental is at 35 hz and you cut it - you won't notice much difference - because it was never loud enough to matter in the first place.

but that's not because you can't hear 35 hz.  it's because you didn't EQ for the Equal Loudness contours like i have.

granted in headphones that is free bass.  with PA subs it would quadruple the cost of your system to run that EQ curve.

but my super duper horn sub design that is part of the super duper array system design are designed to reproduce precisely the same kind of EQ curve that i am already running on my headphones.  that is the design is to run enough sub-bass boost to match Equal Loudness curves, which is way beyond the standard house curve.

if you had that level of bass boost in the 30 hz area the idea that fundamental doesn't matter would fall apart ...

in other words what you call science ( the whole missing fundamental concept ) is probably just cope ...

because it is not feasible for you to reproduce the fundamental at 10 decibels above the level of 2nd harmonic ( which you would have to do given equal loudness curves ) you simply say that it doesn't matter.  because it really doesn't if you can only play it at same SPL as the 2nd harmonic, in which case due to Equal Loudness curves ( formerly Fletcher Munson Curves ) the 2nd harmonic will mask the fundamental.

so it's not that i don't know science.  it's that your subwoofer is not big enough.

don't cry now.

LOL
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RoadRunnersDust Quote  Post ReplyReply Direct Link To This Post Posted: 17 April 2025 at 11:33am
This guy LOLLOLLOL

You’re talking about headphones and the bottom two octaves like that doesn’t *completely* devalue any comment you have to make about sub/bass reproduction.

At this point I’m convinced you’ve never been in the same postcode as a system capable of reaching below 30Hz let alone owned one.

At no point did I say the fundamental has no effect or cannot be heard, I repeated the well known feature of human hearing that the 2nd harmonic has more to do with perceived loudness than the fundamental. Loudness has *nothing* to do with SPL.

The idea that you think 30dB of boost is achieving anything of practical or positive result is hilarious though Clap
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Post Options Post Options   Thanks (1) Thanks(1)   Quote RoadRunnersDust Quote  Post ReplyReply Direct Link To This Post Posted: 17 April 2025 at 11:37am
As to your previous post, I’m out so I’ll address it later but suffice to say that your back-peddling, point-dodging and self-contradiction are all tell tale signs of someone caught bullshitting Embarrassed
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fatfreddiescat Quote  Post ReplyReply Direct Link To This Post Posted: 18 April 2025 at 9:30pm
Originally posted by madboffin madboffin wrote:

I have long retired but when I was working with large (festival and touring) systems I always set the crossover limiters just below the clip point of the amplifiers. I don't remember blowing any speakers...

If you drive a speaker with square waves from a heavily clipped amplifier it will be getting more power than you might expect from the amplifier's specified maximum output, which is for an undistorted signal.

Speaker failures are normally due to burnt out voice coils caused by excessive power, and damage due to over excursion is relatively rare.
Having said that, I once had to investigate a pile of bass bins that came back from a festival with a couple of dozen failed 15" drivers. The system tech (not me, I wasn't there) had failed to set up the limiters properly, the LF amplifiers were Macrotech 3600s, and the last act of the event was Prodigy. If you aren't old enough to have seen or "experienced"  them, well, they were notoriously loud and their music produced a lot of low end...
All the bad speakers had been driven well beyond their xmax and had crumpled coil formers and damaged neck joints. Those 3600's could produce a lot of peak power. An expensive mistake.
Was that an EAW850 system by any chance? If not, it wasn't the only time the Prodigy system didn't survive the night.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote madboffin Quote  Post ReplyReply Direct Link To This Post Posted: 18 April 2025 at 10:13pm
Originally posted by fatfreddiescat fatfreddiescat wrote:

Was that an EAW850 system by any chance? If not, it wasn't the only time the Prodigy system didn't survive the night.

No, it was an F2. But I know it wasn't the only rig to suffer that fate.

The warehouse manager had a nice trip to ATC at Aston Down with twenty-something L1540s for them to recone. They had a big laugh when someone in the hire company's office (again, not me) asked them if it was a warranty job...

Funny thing is, the reason I wasn't looking after that job was because I was working as system tech for another company, with an almost identical system at another festival. Prodigy also played that one. The limiter lights on the crossovers were flashing all through the show, but none of the clip lights on the amplifiers were, and yes I was watching *very* closely. All the speakers survived...




Edited by madboffin - 18 April 2025 at 10:14pm
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