A Question That Has Burned In My Mind For Years...

[MarkWComer]

Absolutely Mark, but alot is quantitative...

I find it amazing after all the electronics, and electromechanical devices a recording goes through that a good system can approach sounding close to a live performance, meaning non amplified instruments..

Agreed. I run sound for my church, a lot of times I will say to someone “cut about 4db from the upper- mids to this vocal” to cut sharpness. A quantity can and often must be applied to reach a good subjective balance.

 

[laatsch55]

Keeps life interesting..

 

[pennysdad]

So differences in frequencies are a result of different voltages??

I should've included that at that operating voltage the diaphragm movement is still minimal regardless of frequency and not enough to pop it.
Voltage is normally associated with SPL, [the more the louder] and at those minimal voltages there just isn't enough to do damage.

 

[MarkWComer]

So differences in frequencies are a result of different voltages??

Wider excursions in a transducer create more current. This depends more on amplitude than frequency. Frequency changes in an inductive circuit is what makes your crossover networks operate ( in conjunction with a capacitor).

 

[pennysdad]

Wider excursions in a transducer create more current. This depends more on amplitude than frequency. Frequency changes in an inductive circuit is what makes your crossover networks operate ( in conjunction with a capacitor).

Unless you bi-amp with active x-o's.

 

[MarkWComer]

Unless you bi-amp with active x-o's.

But... an “active” crossover is still a crossover- a bandpass filter. You’re just changing the method of directing the frequencies.

 

[pennysdad]

But... an “active” crossover is still a crossover- a bandpass filter. You’re just changing the method of directing the frequencies.

I was just referring to your 'inductive circuit - capacitor' bit.

 

[MarkWComer]

I was just referring to your 'inductive circuit - capacitor' bit.

Right... understood...
But the basic principle still applies.
Although the woofers are fed in a different way, the mid|high will still be subject to a crossover.

 

[Gepetto]

... & yet a microphone does the whole thing with only one tiny little diaphragm.

tiny size, low mass is key which is achievable with a mic diaphragm since it is just a receiver, not a transmitter.

 

[Gepetto]

Lively discussion there fellers, thanks Mark, you graphs explain things very well.

I find it amazing a driver can do what it does...even the harmonics..

The harmonics you are likely referring to come from the mid and tweeter.

 

[FredR]

This discussion has burned out my mind!

 

[laatsch55]

I think it's great!!

 

[Gepetto]

Next we will talk about how video works and how our eyes can see all those colors

Great stuff indeed.

 

[MarkWComer]

Next we will talk about how video works and how our eyes can see all those colors

Great stuff indeed.

What kind of video? Starting with the rotating disc Baird system, Farnsworth’s iconoscope / kinescope system, photomultipliers or CCD sensors?

That’s a deep hole, there!

 

[Gepetto]

What kind of video? Starting with the rotating disc Baird system, Farnsworth’s iconoscope / kinescope system, photomultipliers or CCD sensors?

That’s a deep hole, there!

For sure...

 

[pennysdad]

Right... understood...
But the basic principle still applies.
Although the woofers are fed in a different way, the mid|high will still be subject to a crossover.

I've run active systems forever, even at home.
In my days of working r'&'r all systems were active throughout and generally 4-way [bass, low mid, hi mid, hi] and then multiples thereof. Single, double, quad, etc etc.
... & then there were the concert systems. 100KW plus and growing. Left & right stacks & centre clusters, & then delay towers.
... & then the health authorities started to clamp us down from 135dB SPL's down to 110dB. That's a massive drop.
It's never been the same since. May as well just go home and play a record.

 

[Billboard]

135db is loud, what bands were running that volume, also who is limiting concert volume? What country?

 

[MarkWComer]

I've run active systems forever, even at home.
In my days of working r'&'r all systems were active throughout and generally 4-way [bass, low mid, hi mid, hi] and then multiples thereof. Single, double, quad, etc etc.
... & then there were the concert systems. 100KW plus and growing. Left & right stacks & centre clusters, & then delay towers.
... & then the health authorities started to clamp us down from 135dB SPL's down to 110dB. That's a massive drop.
It's never been the same since. May as well just go home and play a record.

I have to admit that you’re in a completely different world from me. No experience with active bandwidth separation whatsoever. I understand why these methods were used, never used them myself. Looks like I need to do some reading!

 

[MarkWComer]

I've run active systems forever, even at home.
.

This looks like an opportunity for me to ask some questions...

I want a subwoofer! I like my ADS 1290 speakers, except one thing: they’re a bit thin on the bass. I can drive them harder with an EQ, but then I hit a limit to the cone excursions.

I’ve been looking at a Klipsch (recommend another, if you want..) sub. I see that they have connections from the amp and then to the speakers. This is an active xo, correct? Or should I connect the pre out to an active xo and feed two separate outputs (now that I have two amps). For the second option, I want to keep the higher bass directed to the 1290s, and the extreme bottom to the sub- I suppose these xos are tunable?

I have no experience with these, as I’ve said before, I’m curious to hear your thoughts. Thanks!

 

[pennysdad]

135db is loud, what bands were running that volume, also who is limiting concert volume? What country?

ACDC were one. You could hear them from 8km away. Their sound guy was a good mate of mine at the time. Cold Chisel, The Angels [all Ozzie bands] were others. There were lots of bands towards the end of the 80's that were right up there. We [me included] were all pretty mad and it became quite a competition.
Eventually the EPA [in Australia] stepped in and changed everything.

Lots of info can be got here: https://en.wikipedia.org/wiki/Loudest_band but some actual figures were not recognised for some reason or other.

It can be done, as long as it's CLEAN.