Watts vs Volume (db)

[saturated]

In car audio competitions you measure SPL.  Does a given system with a 200W amp sound twice as loud as the same system with a 100W amp?

I got tickled when I read this  as much as I groan when I hear them thumpers driving by I am intrigued by the idea of a contest which I presume the goal is to be the loudest?

If so I think I will keep an eye out for any local event like that it would be fun to watch
 

[JonnyDeth]

In car audio competitions you measure SPL.  Does a given system with a 200W amp sound twice as loud as the same system with a 100W amp?

I got tickled when I read this  as much as I groan when I hear them thumpers driving by I am intrigued by the idea of a contest which I presume the goal is to be the loudest?

If so I think I will keep an eye out for any local event like that it would be fun to watch
 

That question is why you really want to understand what VAR is, how to calculate the capacitor for your selected speaker, and then run tests using a sine wave @100 Hz to see how many VAR/Watts it actually sees from that amplifier, probably 10 Khz or at least around 6 to 7 too.

The kid that set the original world record that's since been broken used a specific series of pioneer subwoofer and that series of subwoofer amplifier. Pioneer spared no expense and recruited a degree bearing engineer and techs to design the entire line. They designed the amps so what they produced @1 Khz was also the same as they produced @100 Hz as well as all the way down to 25 Hz, this is why VAR is actually a critical detail when it comes to how much volume you can expect from the lows, mids and highs of a particular woofer and amplifier set, and what is the quality also going to be like.

A speaker whose resonance Q ranges down to 100Hz and still sees 75% of the VAR/watts it will see at 1 Khz will be an absolute monster, even if it's only rated for 90dB rather than 100. The dB sensitivity is still generated by 1-watt @1 meter, so it's not the critically defining feature to how much volume it's ultimately going to produce. It's just a test produce for reference when you're speaker shopping. If it's 110dB vs 95dB, but the 95dB speaker handles 5x the wattage, it's generally going to be louder than the one rated at 110dB when you max their wattage, but it won't be obscene when you compare them, and it's also likely to be better quality in sound fidelity.

I don't have extremely deep interest in car audio, but I do like having a competition class subwoofer in the trunk of my vehicle. My focus for audio engineering will always be focused on music equipment, but also when it comes to signal processing technology, that's going to include car too. I have some rather clever ideas for subwoofer crossovers that will give you brutal volume and thump out of a cheap ass subwoofer and amplifier that I've used in the past. When I finally moved to a competition subwoofer and much stronger power amplifier, it was significantly louder, but only about 20% with a significant amount of rumble. The cheapo was still only about $80 total investment excluding the enclosure I built, and the competition one setup was about $350! It was definitely worth it, but it also wasn't an obscenely dominating increase in performance. I've also been through 3 competitions subwoofers since that one after accidently frying it and having to buy 2 more is what was obscene.

[aquataur]

I'll tell you a funny anecdote for your delection.

About 30+ years ago I had made an active loudspeaker system consisting of two satellites (mid-treble) and a subwoofer. This was made according to a Siegfried Linkwitz design.
I had bought 60W modules to power all 5 speakers, but at the time I was not very proficient. Some decades later I threw the electronics away and replaced them with DIY class-D modules (kits). That worked great.

Just I did not know what power they were outputting. In fact I was not interested in the power, but rather in the voltage headroom, in order to avoid them clipping.

So I devised a small µC operated analyzer that drove 10 LEDs, to show average and peak hold values, to give me a clue where I was. One for each amp, so 5 of those in total.

The unit was tested thoroughly on the bench. After installing, the LEDs did not register.
They did not show anything. Until I found out, that even after playing in the living room at party loudness levels (which you would not like to be subjected to for long), the power output was still below the threshold of the display: 1Watt. You would not believe how loud 1W is.

I then changed the code and installed a 10:1 "loupe" that automatically reverts to normal once the threshold has been triggered, before it falls back with a delay of a minute.

The measurement was by no means scientific, just a conversion using an 8 Ohm resistance, but it gave you a very good indicator.

The interesting thing was that the dance of the LEDs remained the same (the display being logarithmic), regardless of the power. It also showed that, beyond that 1W point, the wattage was climbing shockingly fast despite a perceived mediocre increase of loudness.

We all know that but it comes as a surprise when you encounter it.

[JonnyDeth]

I'll tell you a funny anecdote for your delection.

About 30+ years ago I had made an active loudspeaker system consisting of two satellites (mid-treble) and a subwoofer. This was made according to a Siegfried Linkwitz design.
I had bought 60W modules to power all 5 speakers, but at the time I was not very proficient. Some decades later I threw the electronics away and replaced them with DIY class-D modules (kits). That worked great.

Just I did not know what power they were outputting. In fact I was not interested in the power, but rather in the voltage headroom, in order to avoid them clipping.

So I devised a small µC operated analyzer that drove 10 LEDs, to show average and peak hold values, to give me a clue where I was. One for each amp, so 5 of those in total.

The unit was tested thoroughly on the bench. After installing, the LEDs did not register.
They did not show anything. Until I found out, that even after playing in the living room at party loudness levels (which you would not like to be subjected to for long), the power output was still below the threshold of the display: 1Watt. You would not believe how loud 1W is.

I then changed the code and installed a 10:1 "loupe" that automatically reverts to normal once the threshold has been triggered, before it falls back with a delay of a minute.

The measurement was by no means scientific, just a conversion using an 8 Ohm resistance, but it gave you a very good indicator.

The interesting thing was that the dance of the LEDs remained the same (the display being logarithmic), regardless of the power. It also showed that, beyond that 1W point, the wattage was climbing shockingly fast despite a perceived mediocre increase of loudness.

We all know that but it comes as a surprise when you encounter it.

You never caluclated the power for any of this to make sense because it doesn't. I'm an electronics engineer, not a DIY guy which all due respect, is a community with a lot of nonsense and pseudoscience in how things work, what information means, the literally quantum theories of materials, circuits etc. etc. etc.

Without simply clamping the amplifier, getting a voltage and current reading with a 1 Khz sine wave test tone, there's not much to be said other than you made a cool DIY project that worked well enough but you have no effective understanding of.

I've been there. I built many things like this when I was a DIY nomad for about 6 years but eventually, I got sick of now truly understanding and all the nonsense from forums and social media fraudsters and I went to a technical college that teaches the patent science when I was 32.

Every single device and project is just and endless universe in itself. There's endless options, endless details to modify through D.C. and A.C. analysis, probing every circuit node for a variety of test equipments producing data and then modifying things based on that.

1 watt is very loud through a very light weight cone with a modest magnet size and a very hot signal pouring into it within it's bandwidth where the cone's damping factor doesn't result in physical distortion.
1 watt under the right circumstances will give you permanent hearing loss.

Wattage in itself is a misgiving dataset because inductors and therefore speakers do not see wattage, they see VAR; Volt Ampere Reactance. This is calculated based on the phase angles of voltage and power meeting in timing at a very certain point, and that chronological synchronicity point tells you the peak resonant frequency, the VAR which we can relate virtually to wattage, and the effective bandwidth to power efficiency based on the circuits Q.

It's just a very complicated process in terms of what you cannot learn through DIY study in 99.99999% of cases. You have to go through very structured curriculums of some form and commit to them. Fulfill them in 100% of requirements and if possible, take quizzes and then tests on them.
In the end, there's no supplementing a curriculum with DIY wandering and misunderstandings based on personal ideas and association of those ideas with science based information you simply don't understand.

Udemy and the other online non-credit colleges have a lot of great courses that will take you the distance to being an electronics engineering, but take that with a grain of salt because they all teach "conventional current theory" which is a theory in particle physics that's unfortunately a pseudoscience.
You'll be a competent engineer but never truly a scientist. Technical colleges teach the electron model for mass, energy and motion of all phenomenon in the universe, not just technology and electro-chemical events in nature or even manmade industrial processes.

Learning conventional theory really puts a despicable set of shackles on the student's brain. It can certainly be overcome after the fact, but you have to really want it. It doesn't just correct a shitload of electrical theory they teach wrong but all physics from quantum to classic scale and the countless things they have wrong.

Every field of science today is based on the proton model of mass, energy and motion for understanding all phenomenon in the universe and it's an ass backwards pseudoscience equivalent to shoving food in your crack and expecting it to come of your mouth as feces.
I suppose when all of these theoretical physicists in media make all sorts of ridiculous claims based on totally fraudulent theories, that is virtually the crap pouring right out of their mouths.

This is why technology has been at a near dead stand still for decades.

[aquataur]

I totally agree with you, although I don´t know what your overall message is and whom you direct this towards.

As far as my little box goes, I made quite clear that this is non scientific, however it gives me a good gauge for how close to clipping I am. Labelling such a scale in Volts is kind of awkward and non portable, but an approximate conversion to amplifier power is familiar.

My midrange drivers are low efficiency, and they need considerably more power.
None of this takes the efficiency and thus the loudness into account, and it is not meant to.

I was also interested in seeing if and how much peak power and average power differs for the different frequency ranges. That comes into the bargain.

The idea for this box goes back to a design by J. Linsley-Hood, who too wanted an indicator for the available headroom too, although the practical realization was entirely different:

I use the term "watts" in this context very loosely, in that what one is really referring to is a p-p voltage swing, which could only be related to watts if one knew the RMS equivalent value - very difficult to determine for music waveforms - and if one's loudspeakers were truly resistive loads of a known value. Nevertheless, the hi-fi industry has grown up around the use of this terminology, and I must do the same.

- Build a Peak drive indicator, by J. Linsley-Hood, Hi-Fi News & Record Review, p.63ff, Oct. 1980.

So you may call that amateurish, but it serves the purpose.
Anyway, the purpose of my original post was to illustrate the wrong perception of loudness and amplifier power by telling the amusing story, and not to claim re-invention of the wheel.

[JonnyDeth]

I totally agree with you, although I don´t know what your overall message is and whom you direct this towards.

As far as my little box goes, I made quite clear that this is non scientific, however it gives me a good gauge for how close to clipping I am. Labelling such a scale in Volts is kind of awkward and non portable, but an approximate conversion to amplifier power is familiar.

My midrange drivers are low efficiency, and they need considerably more power.
None of this takes the efficiency and thus the loudness into account, and it is not meant to.

I was also interested in seeing if and how much peak power and average power differs for the different frequency ranges. That comes into the bargain.

The idea for this box goes back to a design by J. Linsley-Hood, who too wanted an indicator for the available headroom too, although the practical realization was entirely different:

I use the term "watts" in this context very loosely, in that what one is really referring to is a p-p voltage swing, which could only be related to watts if one knew the RMS equivalent value - very difficult to determine for music waveforms - and if one's loudspeakers were truly resistive loads of a known value. Nevertheless, the hi-fi industry has grown up around the use of this terminology, and I must do the same.

- Build a Peak drive indicator, by J. Linsley-Hood, Hi-Fi News & Record Review, p.63ff, Oct. 1980.

So you may call that amateurish, but it serves the purpose.
Anyway, the purpose of my original post was to illustrate the wrong perception of loudness and amplifier power by telling the amusing story, and not to claim re-invention of the wheel.

It was that you were saying things in such a way that you did word them in regards to being scientific even with prefacing it with it not. When you start using the unique dialect to certain formal fields, it's still taking responsibility for those terms under the effective understanding in that field.

When you say the voltage would tell you when you were close to clipping, it was a "metric" you had created based on the gear you smithed together to show you some form of measurement.
In truth, that is the basis for all sophisticated, recorded science. Build something that generates information that is consistent in relationship to what you're also witnessing and then refine it.

In engineering, we tend to create a theory, build something from our imagination based on that theory, and if we successfully generate the effect we were envisioning, we refine it by applying staples of science because of where the world is at in technology.

With an 8 ohm impedance for your device though, you're seeing a lot of current. Without seeing the device, I doubt it was actually 8 ohms and much higher. There's also the fact that because of how you're obtaining your signal into those devices, if that device clips the active semiconductors or their passive diodes inside, it's also going to be witnessed by your speaker.
Whatever one experiences, so does the other.

I would bet your gizmos are far higher in resistances to see a large voltage drop but not current. If you're generating theoretically 100 watts, that's surely 3 to 4 amps of current.
Your VAC output is likely to be approximately 20 to 50 volts depending. Current for a 100 watt amp will typically be somewhere between 1.5 to maybe 3-4 amps and of course, with the voltage within the range I gave so it's calculated to approximately 100 watts.

In terms of isolating your monitor setup, it's much better to sample the signal with an incredibly high resistance and then increase the amplification within your device, design a driver that samples off that amplified signal to control the visual monitor, and so if you were to max blast your amplifier and speakers, if something distorted within your gizmo, that huge input impedance would make it totally inaudible within the speaker.
Just finding it within the speaker's signal with diagnostic equipment would become a pretty difficult task and possibly impossible.

I had fun as a hobbyist, but going to school freed my mind allover again and gave me a far more complex medium to create in than music and I'm a symphonic shredder that can hold my own against the biggest names on Earth. I have a style that no body sounds like, not even slightly, and invented a technique that's never existed I call Dypeggios.
There are much better guitarists, but I can still outplay them if that makes sense.

Anyway, I'm neck deep in my own company development and hopefully will launch my guitar and general audio equipment as planned by December this year. I have 3 preamp stages nearly complete that are out of this world. Instead of claiming tube emulation, I outright just configured the transistors to physically do the same thing as tubes and what do you know, unlike every tube emulator, simulator etc. out there that has ever existed, these simple circuits sound indiscernible from tubes.

They fizzle, they zing, they glitter when you hit pinch harmonics instead of grind. It's outright comical to how simple that is, but I'm digress and boasting. My passion for creating in electronics opened up the universe to my control.

[joecool85]

Anyway, I'm neck deep in my own company development and hopefully will launch my guitar and general audio equipment as planned by December this year. I have 3 preamp stages nearly complete that are out of this world. Instead of claiming tube emulation, I outright just configured the transistors to physically do the same thing as tubes and what do you know, unlike every tube emulator, simulator etc. out there that has ever existed, these simple circuits sound indiscernible from tubes.

They fizzle, they zing, they glitter when you hit pinch harmonics instead of grind. It's outright comical to how simple that is, but I'm digress and boasting. My passion for creating in electronics opened up the universe to my control.

Be sure to share here when they come to market - we love hearing about new solid state gear!