Better systems more revealing in soft passages?

[Buckle-meister]

...quality equipment and room conditioning are where it's at, Buckle, no doubt...

Then we are agreed. The only thing left to argue is the percentages to be apportioned to each.

 

[mulester7]

Then we are agreed. The only thing left to argue is the percentages to be apportioned to each.

.....50-50?....

 

[mtrycrafts]

Jaxvon and Mtry hit it on the head. When listening at low levels, the lowest and highest Hz are most difficult to reproduce. All the room treatments in the world won't raise the highest Hz to audible levels compared to those in the midrange. Remember the old "loudness" buttons on equipment - some car headunits still have them. They boost the lowest and highest frequencies when listening at lower levels. Adding an eq would do wonders if one prefers lower level listening - that terrible word audiophools dispise.

One only has to look at the Fletcher-Munson equal loudness curves:

http://www.webervst.com/fm.htm

 

[mtrycrafts]

I'm not sure I agree. As far as I know, sound heard at a point is comprised of the algebraic sum of all direct and reflected sound. I think the room interferes by the same proportion at all levels.

I would tend to agree with you here

I'm not sure I agree. Adding room treatment wont allow sound that wasn't reaching your ears before suddenly to 'make it the distance'.

Again, I would agree with this. Treatment may make it sound better.


But Rip Van Woofer's question was not about listening at low volumes. It was about listening to quiet passages.

Yes, I tended to shift the emphasis to lowering the volume.
A quiet passage at normal listening would be affected by room noise floor. Depending on room soundproofing to lower noise floor, not treatment, would affect what one could hear. But, again. low levels would also could mask other low level signals, hearing is not as sensitive at the two ends of the spectrum, if that is where the low level happens to be.

 

[Buckle-meister]

.....50-50?....

Nah. How 'bout 20/80 respectively?

 

[mulester7]

Nah. How 'bout 20/80 respectively?

.....Buckle, room acoustics is important, sure, but I plan to kill that first bounce as best I can as cheaply as possible, and then look at equipment.....

 

[sploo]

mulester,

I would strongly advise spending some time investigating room treatment.

You will be able to kill first reflections pretty cheaply, but the key is to do it right. Decent fiberglass, rockwool or mineral wool panels will absorb a good range of frequencies, and are very cheap (if you can source panels in small quantities).

A curtain, or some other soft furnishing, will only absorb the highest frequencies, and probably won't help that much.

Remember also that clean bass is very important, and you generally need deep, dense, material in the corners of your room to affect bass.

Having spent some time investigating speakers, room treatment and sources (CD/DVD players etc.) I'm now confident enough to say the following:

1. If you have great loudspeakers, and an acoustically poor room, you are likely to end up with a system that sounds bad - with boomy bass, unclear midrange and treble. Generally you'll get a listening experience that is unpleasant.

2. If you have mediocre loudspeakers, and an acoustically good room, you are likely to end up with a system that sounds reasonable. It won't have the finesse of a great system, but it'll be acceptable.

Different cables, CD players* or amps** will make pretty much zero difference to your listening experience. As Rip Van Woofer noted in a recent post, "The more I read on the subject of acoustics the more I think that the room and speakers are really a single system - the final performance relies equally on optimizing both...and everything else pales by comparison."

I couldn't agree more.


* From listening to a number of CD players, I'm pretty sure some are deliberately modifying the frequency response output, and I believe some even have valve based preamp stages. However, it seems that there's very little difference between most players, as they output a flat frequency response, with distortion below audible levels. I would like to take some time to measure this though.

** Again, valve amps (giving some soft distortion) may sound different, but a well built solid state amp should be pretty linear and put out low distortion levels (thus the differences are not audible).

 

[Buckeyefan 1]

One only has to look at the Fletcher-Munson equal loudness curves:

http://www.webervst.com/fm.htm

Great post.

 

[westcott]

Back to the original question, the reason why better speakers sound better is because they have better frequency response. This allows a speaker to produce the frequencies at the top, middle, and bottom end, no matter what the volume level is. A speakers timbre is half of the equation and and its relation to the rest of the room is the other half, but assuming all things being equal before the upgrade good speakers have good timbre.

 

[Buckle-meister]

...good speakers have good timbre.

What is this timbre? Is it not a colouration added by the speaker's cabinet? If it is, surely we wouldn't want timbre to exist. After all, the most expensive speakers tend to be constructed in such a way as to make the cabinet as inert as possible.

'Course, I could just be thinking of something else...

 

[westcott]

What is this timbre? Is it not a colouration added by the speaker's cabinet? If it is, surely we wouldn't want timbre to exist. After all, the most expensive speakers tend to be constructed in such a way as to make the cabinet as inert as possible.

'Course, I could just be thinking of something else...

This is probably the most concise and easiest to understand explaination of timbre. Quote from an interview with Revel by Secrets of Home Theater.

"Sumit: I find that quite commendable. When designing a loudspeaker what are the three most important aspects of a loudspeaker according to you that one must get right?

Kevin: Timbre is the overwhelming aspect. Based on our blind listening tests timbre is the thing that differentiates between good and bad loudspeakers, but also between good and great loudspeakers. So timbre is kind of a broad term. It incorporates balance, frequency balance, or it can be thought of very roughly as frequency response. That’s a little dangerous because, not to infer that one on-axis measurement tells you what the frequency response is in a loudspeaker. It doesn’t. Other areas like off-axis response are very critical and we’ve learned that very far off-axis response like 60-75 degrees is very critical. Almost no one even measures it, let alone designs loudspeakers that are optimized at that sort of angle. But we’ve looked at real world situations and found that the all-important side-wall first reflection is a function of the speaker’s output at that kind of angle in the vast majority of listening rooms. So it means that you’re going to be hearing that kind of sound. You will hear it with a slight delay, and in many rooms without very much attenuation. So optimizing the response at that kind of extreme angle is very, very important. And then the power response, the reverberant field that we hear a little later in time is also important. So we literally design for all of those areas: the direct sound, the first reflection sound, and the reverberant field, because we know that all those three things are huge contributors to the timbre, to our perception of the speaker’s timbre."

Does that help?

 

[sploo]

Back to the original question, the reason why better speakers sound better is because they have better frequency response...

This is certainly one part of the equation, but there are many other factors:

Better speaker drivers tend to exhibit less distortion, and crossovers with better quality components may well improve sound reproduction.

Better crossover designs are likely to deal with issues such as baffle step, and a skilled designer will probably have also taken a bit more time to compensate for artifacts of the drivers (such as the high-Q peak common to kevlar drivers at the top of their range).

Additionally, a decent loudspeaker enclosure is likely to simply be better built; I've seen a great many 'good' speakers made of chipboard type material (because it's lighter and therefore cheaper to ship). A good, solid, 'dead' cabinet with plenty of internal padding is usually much better.

 

[Buckle-meister]

...we literally design for all of those areas: the direct sound, the first reflection sound, and the reverberant field, because we know that all those three things are huge contributors to the timbre, to our perception of the speaker’s timbre."

Does that help?

Hmm. Kind of. Thanks for providing the information, but I'm really not sure I agree with the part I've quoted.

How can a speaker manufacturer possibly design for first reflections etc? They cannot know of the aspect ratio, size and furnishings of the room in which the speakers will be placed, and therefore their effect on how the sound from the speaker will be perceived.

To say that "all those three things are huge contributors to the timbre, to our perception of the speaker’s timbre" is true, but I'm unconvinced that any speaker manufacturer can design for them.

 

[WmAx]

To say that "all those three things are huge contributors to the timbre, to our perception of the speaker’s timbre" is true, but I'm unconvinced that any speaker manufacturer can design for them.

A speaker that has a [1]smoother, more uniform frequency across a very wide range of angles will always sound better than a speaker that has highly variable response at different angles, when used in a normal room. This assumes, of course, a semi-competant arrangement where one does not place the speakers 6" beside a wall or some other severely compromised arrangement where the early reflections will be at such a close time interval as to cause serious degradation in sound quality. It is a basic matter of sound difference; if the polar responses, which primarily makes up the room ambient/reverberant field are substantially different than the direct sound, then the sound quality will be compromised by this factor. If you are in an anechoic chamber, or a room so heavily treated as to act much like one across a wide range of frequencies, then only the direct sound matters.

-Chris

[1]Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 2
Floyd E. Toole
JAES, May, 1986, Vol. 34, pages 227-235

 

[WmAx]

What is this timbre? Is it not a colouration added by the speaker's cabinet? If it is, surely we wouldn't want timbre to exist. After all, the most expensive speakers tend to be constructed in such a way as to make the cabinet as inert as possible.

'Course, I could just be thinking of something else...

Timber will be modified by any [1] non-delayed resonance that occurs within human audibility thresholds, regardless if the cause is a substantial cabinet panel excitation, cone resonance, microphone non-linearity used in recording, mastering stage equalization, room resonance or purposely induced resonance using an equalizer by the end user. Ironically, while other factors(distortion, clarity, etc.) are more audible with less room reflections/reverberant field, resonances are [1]more difficult to detect as the reverberant field is reduced.

-Chris

[1]"The Modification of Timbre by Resonances: Perception and Measurement", Floyd Toole, Sean Olive, JAES, Vol. 36, No. 3, 1988, March, pages 122-141

 

[westcott]

This is certainly one part of the equation, but there are many other factors:

Better speaker drivers tend to exhibit less distortion, and crossovers with better quality components may well improve sound reproduction.

Better crossover designs are likely to deal with issues such as baffle step, and a skilled designer will probably have also taken a bit more time to compensate for artifacts of the drivers (such as the high-Q peak common to kevlar drivers at the top of their range).

Funny you should mention crossovers.

"Sumit: You mentioned high-order crossovers a while back. Revel speakers have always used high-order crossovers. Several companies take the opposite approach i.e. they use low-order (first and second order) crossovers. What are the disadvantages of using low-order crossover designs? Are there any advantages to using low-order crossovers?

Kevin: Well, we were fortunate enough to have done research that has allowed us to know, to really understand, what are the characteristics that are important to sound quality and what are the characteristics that have some value but less, and those characteristics that don’t have any sonic value and that allow us to make the optimum choices in the design. That all points very, very strongly to high-order crossovers because high-order crossovers are necessary in order to have low distortion which is way up there on the list of important sonic qualities.

High-order crossovers are important to have good dynamic capability without compression. It would really shock audiophiles to see how much the response of most high-end loudspeakers changes at different volume levels. They are like completely different loudspeakers when played even at moderate levels, and it is something that is very directly measurable. So we really focus on making sure that not only is the timbre really accurate, but that it changes as little as possible over a very wide dynamic range. Plus the distortion is below the audible threshold; resonances are below the audible threshold because our research has shown those are really important things.

If we used first-order crossovers, we would degrade the off-axis response, and therefore the timbre, we would completely degrade the distortion characteristics, we would loose our dynamic capability, our freedom from compression because tweeters and mid-ranges are then getting signals that are outside the frequency range that they are really designed to handle. So it’s really mostly heat, and that heat makes the voice coil impedance go up, and as a result of that the filter network is mis-terminated because it’s not seeing the termination impedance it expects to see, and then the response of the crossover is impacted.

So what that means is that when speakers heat up, voice coils heat up, the crossover networks don’t work right anymore and you get peaks and dips in the response, several dB peaks and dips in the response. So with high-order crossovers and with all the things that we are doing in the transducer design to keep the voice coils cool which means we are generally using a very large voice coils which spreads out the heat over a large area, and we’re using in some cases multiple woofers to further spread out the heat. We are using all of these techniques including the way we vent them which forces the air through the gap at the same time, the vents are designed in such a way so that they don’t create noises. It’s a very sophisticated approach to solving the problem with heat. But a big part of that is the high-order crossovers. It’s an essential part of it.



Sumit: What crossover slopes are typically employed in Revel designs?

Kevin: Our networks are always tweaked to result in the smoothest possible transition between transducers. Because of that, their electrical characteristics don’t meet the textbook definition of classical filters, which is why we don’t specify them in our literature. However, the resulting response of the transducer/enclosure acoustic and the filter’s electrical response is close to a 4th-order (24dB/octave) Linkwitz-Riley characteristic.

Sumit: Have you ever heard a good loudspeaker that uses a low-order crossover?

Kevin: I have heard good loudspeakers that use low-order crossovers. I haven’t heard great loudspeakers that use low-order crossovers. They run into these problems. It’s inevitable."

Quote from an interview between Revel and Secrets of Home Theater.

 

[Buckle-meister]

A speaker that has a smoother, more uniform frequency across a very wide range of angles will always sound better than a speaker that has highly variable response at different angles, when used in a normal room.

Understood, but let's not play with the words themselves here. Aren't all speaker manufacturers who design speakers to possess as uniform a frequency response across as wide a range of angles as possible not doing so not to design for the room in which they will be placed, but simply to design a speaker that has better characteristics over another?

 

[WmAx]

Understood, but let's not play with the words themselves here. Aren't all speaker manufacturers who design speakers to possess as uniform a frequency response across as wide a range of angles as possible not doing so not to design for the room in which they will be placed, but simply to design a speaker that has better characteristics over another?

I prefer not to speculate as to why manufacturers choose the design toplogies that they do, since this is wide open for interpretation.You'll have to be more specific, and give examples, otherwise I can not answer.

-Chris

 

[Buckle-meister]

You'll have to be more specific, and give examples, otherwise I can not answer.

All I'm meaning is that I've a healthy skepticism that speaker manufacturers are actually designing 'for the room' (after all, that's not their problem). I'm much more inclined to believe that they're simply trying to manufacture a speaker with the best characteristics as possible.

 

[WmAx]

All I'm meaning is that I've a healthy skepticism that speaker manufacturers are actually designing 'for the room' (after all, that's not their problem). I'm much more inclined to believe that they're simply trying to manufacture a speaker with the best characteristics as possible.

The room is a critical part of the equation. Besides, one need not compromise off axis response to achieve the other quality objectives, if higher cost is acceptable. But speakers are produced that expect the user to use very high level of acoustic treatments. One of the most famous examples was probably Dunlavy Labs. They produced speakers of superb technical quality and linearity. However, they REQUIRED extreme room treatment to basicly render most reflected off axis sound a non-issue, because the polar response was very poor, and to use these speakers in a normal room would render the positive points of the speakers to be useless.

BTW, based on their products, some speaker companies do not even recognize established and credited perceptual research.

-Chris