Reviews and "dynamics"

[KEW]

I have seen the term, "dynamics" loosely mentioned in a couple of reviews.
What does this mean?
Is it reflected in any of the standard measurements?
Maybe I'm wrong, but I get the impression it is more than just max SPL.

Thanks!

 

[Steve81]

I have seen the term, "dynamics" loosely mentioned in a couple of reviews.
What does this mean?
Is it reflected in any of the standard measurements?
Maybe I'm wrong, but I get the impression it is more than just max SPL.

Thanks!

Max SPL is one aspect, but the other aspect is playing without compression. If you took a Klipschorn and an Ascend Sierra bookshelf, yeah there's no question that the Klipschorn will play louder. But it will also reproduce peaks with virtually no compression at any volume level within the realm of sanity in a typical listening space, whereas the less sensitive Sierra will run into problems like thermal compression far sooner.

 

[Steve81]

PS: As far as how it might be reflected in measurements, the long term compression sweeps would probably be a fair indicator.

 

[TLS Guy]

I have seen the term, "dynamics" loosely mentioned in a couple of reviews.
What does this mean?
Is it reflected in any of the standard measurements?
Maybe I'm wrong, but I get the impression it is more than just max SPL.

Thanks!

I think my post in another thread answers your question. This is a big and pervasive problem.

 

[Steve81]

PS: As far as how it might be reflected in measurements, the long term compression sweeps would probably be a fair indicator.

Just to put it into a picture:

The PB10-ISD

http://personal.inet.fi/private/ilkka/shootout3/svs pb10 max.png

We'll compare the 90dB and 100dB sweeps at 60 and 20Hz. At 60Hz, going from 90dB to 100dB nets you a 9dB real increase, which isn't too bad. At 20Hz though, you're gaining a 7dB real increase.

Now compare to the PB13U

http://personal.inet.fi/private/zipman/shootout5/svs pb13ultra 20hz mo.png

At 60Hz, going from 90dB to 100dB, you're getting about 9.5dB real extra output. At 20Hz, you're still also getting a real 9.5dB increase.

So even though we've not reached the limits of either subwoofer, the PB13 is clearly the more dynamic of the two in this little scenario.

 

[pbc]

I think my post in another thread answers your question. This is a big and pervasive problem.

Wow, that was a very informative post TLS!

 

[theJman]

I have seen the term, "dynamics" loosely mentioned in a couple of reviews. What does this mean?

In essence, dynamic range is the difference between the loudest and softest parts of the reproduced sound. A speaker considered "dynamic" handles the variation of frequencies and their intensities in such a manner as to ensure each is clearly distinct from all the others.

Take music for example; there are constant differences in the frequencies and the loudest and softest passages. Those contrasts are the dynamics of the reproduced sound. If the detail and variations are significant, allowing even the most minute aspects to be clearly heard, then that speaker is considered dynamic. The same holds true for a subwoofer; if the individual elements are pronounced it would be considered dynamic.

Is it reflected in any of the standard measurements? Maybe I'm wrong, but I get the impression it is more than just max SPL.

It is not reflected in any measurement, nor is it related to SPL. It's something you can definitely hear though.

 

[shadyJ]

It is not reflected in any measurement, nor is it related to SPL. It's something you can definitely hear though.

I don't buy this. The higher sensitivity speakers all do dynamic range or response well, and they all have very high clean max SPL abilities. Compression sweeps ought to reveal that quality, like Steve said.

 

[theJman]

I don't buy this. The higher sensitivity speakers all do dynamic range or response well, and they all have very high clean max SPL abilities. Compression sweeps ought to reveal that quality, like Steve said.

All high sensitivity speakers have good dynamic range? Seems like a pretty bold statement to make without any basis of reference. Either way, I don't buy a compression sweep can reveal the true story of whether a speaker is dynamic. That test is probably a good indicator of a speakers clarity, but I don't see how it can be considered an accurate predictor of it's ability to properly render detail.

 

[Steve81]

Either way, I don't buy a compression sweep can reveal the true story of whether a speaker is dynamic.

Hi Jim,

Just to help avoid argument, I guess first we should define dynamic.

Sounds Like? An Audio Glossary Glossary: D-E | Stereophile.com

dynamic Giving an impression of wide dynamic range; punchy. This is related to system speed as well as to volume contrast.

In the compression sweeps I cited above of the PB13U and the PB10-ISD, both speakers are asked to run sweeps at a 90dB level, and then another sweep at the 100dB level. Ideally, the 100dB sweep would be exactly 10dB higher at all frequencies than the 90dB sweep. As I noted, at 20Hz, the PB13U tracks this change quite well, increase volume by 9.5dB. Conversely, the PB10 only gains 7dB out of the 10dB it should be increasing. Thus, the PB13U more accurately tracks this volume contrast and it would seem fair given the above definition to class it as more dynamic. Also, given that the PB13U is literally delivering more output, the end user may well perceive it to be punchier as well, although 20Hz may not be the best example for this. If the PB10 exhibited this compression at 63Hz, I'd guess it to be more likely that it would be perceived as being less punchy than the non-compressing (at this point) PB13U.

As another thought, regarding system speed, I suppose the spectrogram and waterfalls would be of help there.

 

[theJman]

Just to help avoid argument, I guess first we should define dynamic.

Agreed - perhaps my definition is a bit broader. I define dynamics not only as the variation between the loudest and softest passages, but also the level of articulation provided. I've heard speakers that can track the variations in intensity just fine, yet the detail of the different elements was lacking. To me, I would not define such a speaker as dynamic. Perhaps others would.

As far as the rest of the measurements are concerned? I'm with you; I think if you look at all of the data -- waterfall, compression, etc. -- you can draw a pretty accurate conclusion about a speakers potential, but to me it seems that would still be speculative until you actually heard it. I'm not convinced, however, that you can make the same assessment by the compression sweep alone. It takes more then just a single test to get an understanding of the dynamics, and ultimately I think you need to judge it by ear as well.

 

[Steve81]

Agreed - perhaps my definition is a bit broader. I define dynamics not only as the variation between the loudest and softest passages, but also the level of articulation provided. I've heard speakers that can track the variations in intensity just fine, yet the detail of the different elements was lacking. To me, I would not define such a speaker as dynamic. Perhaps others would.

As far as the rest of the measurements are concerned? I'm with you; I think if you look at all of the data -- waterfall, compression, etc. -- you can draw a pretty accurate conclusion about a speakers potential, but to me it seems that would still be speculative until you actually heard it. I'm not convinced, however, that you can make the same assessment by the compression sweep alone. It takes more then just a single test to get an understanding of the dynamics, and ultimately I think you need to judge it by ear as well.

Hi Jim,

Yes, it would seem you're taking a broader view of dynamics than I do. FWIW, I don't think anyone would evaluate a speaker's performance by compression sweep alone, especially if you're interested in evaluating the articulation of a speaker. Since this is posted in the subwoofer section, I would say that Ricci's battery of measurements give a pretty good idea of how a subwoofer will perform sans the room (bringing the room into the picture, everything goes sideways). That is to say, two subwoofers that perform similarly within that battery of tests are likely to have more in common sonically than not; of course there is still room for some variation.

 

[Ricci]

Dynamics are related to accurate tracking of the input signal amplitude and therefore to a large extent, output capabilities and freedom from compression. That being the case... Low volume pitch definition and spectral balance are rather different issues than dynamics.

A larger more powerful speaker will be able produce larger more powerful signals, in some sense increasing the potential dynamic range of your playback system. Every system will have a noise floor and also an upper ceiling on the amount of output it can produce. Let's assume that we have sub A, a small compact sub and sub B, a many times larger more powerful subwoofer. Let's assume that the noise floor of the system might be 60dB or so. If compact sub A can produce 105dB maximum at the seats and sub B can produce 125dB. Sub B provides an extra 20dB of possible dynamic range. Whether that is used or not is another subject, but there will come a point if you keep increasing the volume at which the less powerful sub will not be able to produce enough output to accurately track the signal anymore and the volume level of the peaks will be less than it should be which will compress and reduce the dynamic range and contrast between the softer parts and louder peaks by squashing the loudest peaks. This is a distortion of the signal. Additionally speakers operated at the edge of their limits typically have higher THD and do not sound as pure as they do when they are relaxed and well within their operational envelope. Squishing of the signal is one of my pet peeves I listen for.

So at this point you decide to watch the newest Halloween slasher movie first with system A and next with system B. The first time you watch the movie it is late and your kids are in bed so you set the volume to -20 so as not to disturb anyone else too much. At a few of the typical "jump out of your chair" type scary moments there is creepy low volume background bass rumble and some quiet dialog which are about 70dB as typically used to set the mood in horror movies ...This is followed by an abrupt and dreadful sound where the subs are asked to provide 100dB at your seat. A 30dB swing. Both subs accomplish this and the presentation is fairly close between them. Neither had a problem fully preserving dynamic range in the movie. You realize this movie could be fun turned up some with some unwitting guests. Next weekend you have a few friends over and put on the same movie but turn it up quite a bit louder than normal to really impress and scare the crap out of them setting the volume to -5. The creepy background rumble section comes around again at about 85dB and then...wham...Sub A is asked to produce 115dB at your seat on the abrupt scary part but can only manage 105dB compressing the peak of the signal by 10dB resulting in a dynamic contrast of only 20dB instead of the full 30 it should have been. On the other hand you repeat this with sub B and a different set of friends the next day... The creepy background rumble section in the slasher movie comes around again and then...WHAM! Sub B easily produces the full 115dB required to accurately track the intensity of the signal and scares the crap out of everyone.

That's it in a nutshell really. It is the difference between...

driving in the car...quiet background music...through an intersection...BAM!

and

driving in the car...quiet background music...through an intersection...BAM!


This is why terms like "big" sound "ease" get associated with larger systems sometimes. Hence my fondness for powerful subs and large efficient speakers.