Limiter circuit on active monitors [case HS5]

The limiter in most loudspeakers is almost always put there to protect it from being overdrive and damaged.

You shouldn't be running the speaker up into the limiter under normal mixing conditions, so it shouldn't be messing up your mixes.

In the 80's a studio I worked in had EV Sentry 500A's for far-fields. One night, one of the interns was goofing around in the CR with a synth and admitted he could not hear anything (he apparently had the oscillator up past his HF hearing limit) so turned the monitors full blast but still heard nothing. Ended up one of the Sentry's had no sound coming out of the tweeter. I opened it up to luckily find a WW resistor was open. A trip to Radio Shack and some change and we were back in business.

Cheers,
Rock

(I don't know how the HTML tags got exposed, but...)
<quote>
Mar 16, 2017 14:19:41 GMT -4 federico said:
Hello! Thanks for the replies. But please there's a difference here...
</quote>

If limiter is competently designed, There is not a real reliable difference unless you are playing the music very loud or are trying to do sensitive work while at some long distance from them in a very large room or our of doors.

<quote>
Actually if it were psychological, I would probably have loved the cool new 'mod' of removing the limiter.
</quote>

I've heard this argument many times, and it is generally either highly questionable or false.

The formal name for what you are talking about is expectation bias. There are many studies about this, and expectation bias is generally found to be unbiaeed. IOW, false expectations can be positive or negative. This about it, you can always state your expectations either way, that is to say as a positive expectation or as a negative expectation. It is just a matter of playing with words.

<quote>
I do understand the tiniest of distances makes a difference, so I've tested them in the same position, next to each other, and inverting positions.
</quote>

Those are all ineffective tests. To test this properly you would have to clamp your head in a vice. Changing your heads angle also creates audible differences. The area of study is called Head Response Transfer Functions.

<quote>
I also understand there's dozens of fake nonsense A-B tests... I've seen and heard them too.
</quote>

Almost all listening tests produce false results unless the audible difference is of a kind already known to be audible in the specific case. Sometimes you can change small things and eliminate the ability to hear a difference reliably. When you are not hearing a difference, you are very often convinced in your mind that you are hearing a difference. And, when differences are small you may be convinced that you are not hearing a difference, but if you have written down your responses to many (>=16) trials a quickbut formal statistical analysis may show that you were actually hearing a difference a statistically significant percentage of times.

The one word scientific word for a proper test is a proven ability to fail or falsifiability. IOW any valid test has to be provably able to fail, except for relevant changes in the dependent variable. In the case of audio signal limiting, this requires that the test be:

(1) Level matched

(2) Time synched

(3) The identical same test sound to a precision of less than 10 milliseconds.

(4) Double blind, which is to say that no person or other thing that possibly affect the outcome of any trial has any knowledge or connection to whether the independent variable is present or not.


<quote>
But please believe me here there is a difference here. Perhaps the difference was there all along?
</quote>

It is your responsibility as the person who is doing the test and bringing the results to us, to ensure that the test is in fact testing the influence you re saying that it is.

<quote>
In this case the limiter circuit makes a difference even at low volumes. This is a video made with the schematic and component removal.

www.youtube.com/watch?v=V-jFU7pYXIE
</quote>

Several comments: I don't doubt the sincerity of the person who made this video, but he makes some errors, one actually fairly trivial, the rest both commonplace and serioius.


The first error is actually a nit in execution. In fact he does too much work. My philosphy iwth modds is do as little as possible, and of course do it reversibly. All that he needs to do is disconnect the output of the limiter. Just unsolder the collectors of TL401 and TL403. If you prefer no soldering, break the trace between the text D407 and Q405. I use a miniature abrasive tool (Brand name Dremyl) for such things, or a quick slice or two with an Xacto knife.

The second error is that he does not do any technical tests to show that the limiter is hurting sound quality when it is not limiting.

He's got an impressive lab with expensive gear, and it all goes to waste because he apparently does not know how to set up a proper experiment.

I have a good enough lab, but I can also show how to do the required technical tests with a very minimal investment in a few small electrical parts and some household items. Just goes to show that impressive gear is easy to buy, but a good technical education takes much more time, effort, and money.

The third mistake is the really gross one, and also a very common mistake like the second. I already covered the details above. His listening test so improperly done that it is not even a test. Its basically technical errr, self-abuse. ;-)

Indeed. The text I edited had proper tags in it with braces, but what the forum software made of it, is what you see.