JBL 4309 Review (Speaker)

[amirm]

Meanwhile, the difference in output from 86dB to 96dB was only 6dB; meaning a loss of 4dB due to built-in limiting. There is no way, whatsoever, one could look at the HD data and presume such a difference in SPL levels would occur. And this isn't linear; other speakers behave differently.

That is for an active speaker which uses limiters. It has nothing to do with the topic of passive speakers/drivers limiting.

 

[amirm]

Anyway what do you all think, maybe get a dedicated thread so folks can go off?

Good suggestion. Go ahead and create it.

 

[hardisj]

That is for an active speaker which uses limiters. It has nothing to do with the topic of passive speakers/drivers limiting.

I know that. Which is why my paragraph said:
“And there are clearly cases where a limiter is used, which means the bass distortion doesn't increase much but the limiting of the output is huge.”

The point stands:
You can't simply look at HD and infer compression/enhancement. That was a clear-cut example and, thus, the most logical one to choose.

 

[amirm]

I know that. The point stands:
You can't simply look at HD and infer compression/enhancement. That was a clear-cut example and, thus, the most logical one to choose.

The point doesn't stand. You picked a special case where there is electronic limiting and showed what is otherwise quite obvious. We are discussing the much larger topic of passive speakers for which you have no confirmation of anything being material or correct indications of "compression." Just a differential frequency response with highly amplified scale masquerading as something more important.

 

[hardisj]

The point doesn't stand. You picked a special case where there is electronic limiting and showed what is otherwise quite obvious. We are discussing the much larger topic of passive speakers for which you have no confirmation of anything being material or correct indications of "compression." Just a differential frequency response with highly amplified scale masquerading as something more important.

For that matter, I have tested other powered speakers (708p, for example) without this issue. The HD looks fine. No limiting. The LS50WII HD looks fine. Tons of limiting.

Now, how do you expect the general public to look at the HD data and determine that the LS50WII has 4dB of limiting when they have seen clear examples of other powered speakers without limiting? You can't. That's an unreasonable ask. Therefore, having that real, tangible data is helpful. It really is as simple as "hey, I can provide this data"... boom, there you go. No more tryin to guess at what the limiting (or compression) is.

 

[hardisj]

The point doesn't stand. You picked a special case where there is electronic limiting and showed what is otherwise quite obvious. We are discussing the much larger topic of passive speakers for which you have no confirmation of anything being material or correct indications of "compression." Just a differential frequency response with highly amplified scale masquerading as something more important.

Yet, you cite HD as a metric that will tell us this. You have stated as much in another thread where you said my compression testing was (paraphrasing) useless. My point is simple: You cannot use HD as a metric for compression or limiting or any (useful) metric of a frequency response change. You can assume... but you don't know. And your assumption is likely to be off.

 

[amirm]

Yet, you cite HD as a metric that will tell us this.

No I have not. My method of determining dynamic range limiting is through listening with specialized music tracks. If people want objective tea leaves for it, then I said distortion graphs provide that. If I thought that was enough, I would not have performed the listening tests.

Your method of frequency response has not been demonstrated at all to have value, again beyond the obvious cases of active speakers. Come back when you have proof of audible results, or objective proofs of audible compression and then we have something to look at. Otherwise it is a proposal for a measurement with shaky foundation.

 

[hardisj]

Fine, I'll play. Let's look at the Emotiva B1+. 86dB and 96dB HD:

By eyeball you can see that the difference in distortion from about 50 to 800Hz is about 10dB... or about 1 to 2% depending on where you pick your mark.

At 100Hz the HD shift is -44dB (86dB) to -32dB (96dB). A 12dB swing in distortion. The compression is 0.00dB.
At 70Hz the HD shift is about -44dB (86dB) to -34dB (96dB). A 10dB swing in distortion. The compression is 0.50dB.

Now, tell an average person that and they would say "well, why aren't they linear?" Why does 12dB THD result in less compression than 10dB? That's a reasonable question. And I don't have a solid answer for that. Yet, those are the results.

So, again, you can't use HD to determine compression levels.


Now, if you go back to the "well, it's only 0.50dB" argument (which I said I agreed... probably not a big deal) then I'd remind you to stay on topic. You presume HD tells you all you need to know. I have just proven that it is not that simple.

 

[ROOSKIE]

Good suggestion. Go ahead and create it.

Passive Loudspeaker Speaker Compression/Dynamic Compression

Howdy, this topic got hot in the JBL 4309 thread. A lot of very interesting points have been mentioned in that thread. Let's make the jump to a dedicated thread. Maybe the mods can move some relevant posts here so there is some context and fuel to work with in this thread. Things discussed...

www.audiosciencereview.com

Hope this works. Here it is.

 

[hardisj]

My method of determining dynamic range limiting is through listening with specialized music tracks.

Are your ears linear? Nope. Earl talks about masking in my conversation with him linked above.

Using your ears as a sole metric for determining dynamic range, honestly (no hyperbole or picking on you), IMHO, undermines your efforts to provide objective data. It seems like the wrong hill to die on.

 

[hardisj]

Your method of frequency response has not been demonstrated at all to have value, again beyond the obvious cases of active speakers. Come back when you have proof of audible results, or objective proofs of audible compression and then we have something to look at. Otherwise it is a proposal for a measurement with shaky foundation.

My method is simply testing what the frequency response differences are as you vary the output. The exact same thing Sean discusses above in my topic. If you don't agree with it then you are welcome to discuss it further with him and Earl Geddes.

You may disagree. It doesn't make you right.

Now, let's imagine this scenario:
You test a speaker at 1v, yielding a mean SPL of about 76dB.
You test a speaker at a higher voltage, yielding 86dB SPL.
Yet, the difference in the result isn't a straight 10dB. It's different. Now, your bass output is lessened. What?...
Well, we know - for a fact - that will alter the preference rating. How much? Well, no one has taken the time to do that testing. And it would depend on the severity of the non-linearity of the results.

Now, let's say two people are arguing about a speaker's performance. They both listened at the same volume. But one guy was 1 meter away while the other was 4m away. If we have proof that the response changes with output then we can work to make reasonable correlations about why the two had a different experience. That, at least to me, is the science of what we do as reviewers. That, to me, is the interesting stuff. Whether their experience be with passive or powered (limited) speakers. If they don't know the speaker output is limited or compressed then we are left to only look at other options or - worse - the subjectivist fellow of the two says "see, we don't hear the same" because they assume the SPL is linear... add 10dB, you get 10dB. But we know from the data it doesn't work that way.

Absolutely, most speakers don't perform terribly in this regard. But, on the flip side, we see HD increase dramatically in some cases. But it doesn't make the purpose of the testing moot. It just means that most speakers do well in this regard. And then we focus on other aspects.

 

[PierreV]

Why is it that people can't ever agree to disagree?

 

[hardisj]

Why is it that people can't ever agree to disagree?

I tried that. I really did.

But, like I said, Amir disagrees. He is bent on proving me wrong. I am bent on explaining my rationale. We are at a stalemate. Nothing I do or say will change his mind and nothing he does or says will change my mind.

And that is OKAY.



This is pretty much how Amir and I view each other at this point:

 

[hardisj]

I do ask that if this thread is broken out, that someone carry over my posts to the new one. I really don't want to copy/paste it elsewhere. I don't have the time for it.


And with that said, I've gotta bail on this topic. I really do got stuff to get done. Peace, ya'll.

 

[Newman]

They both listened at the same volume. But one guy was 1 meter away while the other was 4m away. If we have proof that the response changes with output then we can work to make reasonable correlations about why the two had a different experience. That, at least to me, is the science of what we do as reviewers.

The guy 4m away hears a completely different direct/reflected sound ratio, and that is almost certainly the reason for the different experience, combined with completely different room mode behaviour at listening positions 3m apart down the length of the room (since your compression issues almost always are about the bass).

Taking the scenario you described as your best example of when to discuss dynamic compression, and making any kind of statement about dynamic compression instead of the two causes I described above, would be extremely unwise.

 

[daftcombo]

I don't know why you guys are still arguing. Having a compression test data is definitely better than not. If it matters a lot or not is something different, the same we don't know if CSD, groupd delay, phase graphs... are really useful.

 

[hardisj]

The guy 4m away hears a completely different direct/reflected sound ratio, and that is almost certainly the reason for the different experience, combined with completely different room mode behaviour at listening positions 3m apart down the length of the room (since your compression issues almost always are about the bass).

I was so stuck on my perspective, I didn’t think about that. So, yes.

My other analogy regarding simple volume is of merit, however.

 

[hardisj]

I don't know why you guys are still arguing. Having a compression test data is definitely better than not. If it matters a lot or not is something different, the same we don't know if CSD, groupd delay, phase graphs... are really useful.

Right?

Just like we do with distortion…

 

[Spkrdctr]

Nice speaker. That Amir enjoyed it pre-EQ is possibly the billionth data point gathered over a century that might lead to a working hypothesis: within reason, frequency response doesn't matter very much. Perhaps the brain can post-EQ. Certainly we can hear subtle touch and nuance in musical figures - even though the in-room SPLs are violently doubling and halving (at best) through the octaves.

Bingo, you are a winner. The brain will "cover up" or fix fairly bad looking frequency responses many times. Of course not all the time, but many times the speakers sound great until you see the frequency response, then your brain says "oh no" and your enjoyment of those previously very nice speakers tanks. Then in a few months you have a new different pair of speakers. The two biggest issues with audio is the room interaction and the brain. Usually though the brain makes everything sound better than what it probably is. So, thank heavens for the brain!

 

[Spkrdctr]

That was one of the best man pants responses I’ve heard from anyone in a long time. Well done.

The problem with two men getting into a willy measuring contest is the person arguing with Amirm will say "OK, I have a ruler, whip it out and lets measure" then Amirm says "Ok, but I need to go get a yardstick". The moral of the story is to know who your getting into a contest with!