or Connect
AVS › AVS Forum › Audio › Speakers › List of Reference Level, High Sensitivity & SPL Speakers
New Posts  All Forums:Forum Nav:

List of Reference Level, High Sensitivity & SPL Speakers - Page 18

post #511 of 820
Quote:
Originally Posted by Eyleron View Post

I know what you're saying, but I think the marketed sensitivity has some utility.
A car's "City miles per gallon" rating is considered highly inaccurate and unattainable in any realistic driving, But I consider it at least a benchmark for the best the car could achieve (if they advertise 20 MPG City, I can bet that I will get worse than that, but most likely not 25 MPG).

Likewise, if I think an application needs a minimum of 95dB sensitivity, I feel like I can drop the speakers with < 95dB from the running. Like, I wouldn't worry about investigating the 87dB speakers. 

The problem between your comparison of sensitivity and the MPG on a new cars sticker is this:

The cars are measured in the same manner, so while the number may not reflect what you will actually get, the relationship between each car basically remains the same. With speaker sensitivity, it is not measured the same by every manufacturer. lets take for example a speaker that measures in a chamber 87db one watt per meter.

if that speaker is a 4ohm speaker a manufacture could list it as 90 watts per 2.81 volts.
Another manufacturer could use in room measurement and list the speaker as 94db one watt,2.81 volts.

Now we are talking about the same speaker, but showing 7db difference. Some manufacturers measure using two speakers and some corner load a speaker. So without knowing exactly how the measurement was taken, listing sensitivity means very little.
Reply
Reply
post #512 of 820
Thread Starter 
Quote:
Originally Posted by Bill Fitzmaurice View Post

Measure at low power, measure at full power, and at a few spots in between. What you're really interested in is how much power the system will take before reaching 10% THD. That's your peak. And don't assume if THD is 10% or even higher that it won't sound good. Many's the audiophile willing to lay out big bucks for tube amps for their 'warmth'. Warmth is coloration, coloration is distortion.

I'm confused. I'm trying to reconcile some things here. For instance the CEA2010 testing of long signals and short burst tones for subwoofers. The burst tones typically yield a higher SPL. 

 

If our program's average level is low enough that we're not significantly heating up the voice coil, and thus we're not undergoing thermal compression effects (dynamic jazz, films), aren't the transient peaks going to be a different phenomenon than the long term signal handling? Like we'll be more limited by XMax and magnetic flux effects, etc.? Thus that kind of testing you're describing is not representative of peak handling?
 

Or, are you saying that quick one second sweeps are representative of short term peak handling (like with a long enough pause between tests to allow cooling)? 


Edited by Eyleron - 12/10/12 at 10:19am
post #513 of 820
Thread Starter 
Quote:
Originally Posted by AV Science Sales 5 View Post


The problem between your comparison of sensitivity and the MPG on a new cars sticker is this:
The cars are measured in the same manner, so while the number may not reflect what you will actually get, the relationship between each car basically remains the same. With speaker sensitivity, it is not measured the same by every manufacturer. lets take for example a speaker that measures in a chamber 87db one watt per meter.
if that speaker is a 4ohm speaker a manufacture could list it as 90 watts per 2.81 volts.
Another manufacturer could use in room measurement and list the speaker as 94db one watt,2.81 volts.
Now we are talking about the same speaker, but showing 7db difference. Some manufacturers measure using two speakers and some corner load a speaker. So without knowing exactly how the measurement was taken, listing sensitivity means very little.

Granted, sensitivity specs are worse than a consistent MPG rating and are less comparable between vehicles.

 

I'd still say there's some utility in the number if I know my application has a minimum sensitivity. If I need 95dB sensitivity for a large room that I know I want reference level in, I wouldn't waste time with speakers marketed as 85dB. Such a speaker might even offer a 10" woofer. But if its design was using the woofer to show great extension, then it's not suitable for high SPL dynamics. 

 

In other words, unfortunately, it's probably a safe bet to guess that the sensitivity reported in marketing is the best you'll ever get, and most likely it's worse. But one can still use that number to make decisions. 

post #514 of 820
Quote:
Originally Posted by Eyleron View Post

 
Or, are you saying that quick one second sweeps are representative of short term peak handling (like with a long enough pause between tests to allow cooling)? 
The main thing is to test all in the same fashion. If you want to run the speaker at a specified SPL output for an hour to heat the coil and the run the THD test, fine. If you want to run it with the coil at room temperature, fine. Just do it the same for all tested speakers. If the intent is to see how they compare at reference run them at reference to warm them up, then test them at reference.
post #515 of 820
Quote:
Originally Posted by psgcdn View Post

Don't know Geddes' approach. Link?
I doubt I want to integrate a sealed sub with a horn-loaded sub, but...
http://mehlau.net/audio/multisub_geddes/
http://seriousaudioblog.blogspot.com/2012/05/two-great-articles-on-multiple.html

The idea is to use supplementary sub(s) to cure room mode induced peaks and nulls. "It can be seen as a statistical approach to averaging the sound field. It can be seen as dense interference, like rain drop ripples in a pool. Both are accurate ways to view the situation. But it can also be seen as simply filling in holes. "

If you have a spare sealed box to play with, you can easily get a taste of how it works. The sub does not have to be powerful at all, but it helps if it has variable LPF settings, some sort of phase control (variable preferred) and volume level control.

Assuming your THT is up front with the L/R/C, put the sealed box along the side wall, away from the mains. I have it approx. at midpoint in my room, but I do not think this is mandatory.
Get REW running in RTA mode with the microphone at your LP. Start adjusting controls for the sealed sub while watching in RTA how it affects the FR .
I found LPF and volume trim adjustments most useful in my case, but it may be because for the phase all I can do is switch between 0 and 180 degrees.

If you have not worked with RTA in REW before here is a useful tip I was taught:

1. use one of the RTA modes, not spectrum
2. use "Pink PN" test signal in signal generator
post #516 of 820
Thanks!
post #517 of 820
Thread Starter 
Quote:
Originally Posted by Bill Fitzmaurice View Post

The main thing is to test all in the same fashion. If you want to run the speaker at a specified SPL output for an hour to heat the coil and the run the THD test, fine. If you want to run it with the coil at room temperature, fine. Just do it the same for all tested speakers. If the intent is to see how they compare at reference run them at reference to warm them up, then test them at reference.

That makes sense.

 

So, if I want to test simulating transients, a quick sweep is the way to go? 

Naturally, one could play whatever tones (shaped burst, etc.), but the trick is having software to know the baseline of what's being sent to be able to derive the THD. That's what I don't know how to do with REW, etc.

post #518 of 820
Quote:
Originally Posted by Eyleron View Post

but the trick is having software to know the baseline of what's being sent to be able to derive the THD. That's what I don't know how to do with REW, etc.
With HomlImpulse you don't have to do anything but measure. It gives FR, THD and phase on the same chart. You can turn off any of the displayed charts, and I always do with phase, unless that's what I want to see, as having all three displayed makes for a very busy chart. THD can be toggled to show total THD or any of the sub components, 2nd through 10th harmonic. I wouldn't be concerned over peaks, what you're interested in is what the speaker does at normal listening levels. Of course normal will be a lot different for MK than the rest of us.
post #519 of 820
Quote:
Originally Posted by Bill Fitzmaurice View Post

Not bad, but MKs stacked DR250s gets him to over 109dB/w, per stack. He can get reference from a 15w Lepai running off a battery. eek.gif

That is remarkable!!eek.gif So awesome!!
post #520 of 820
Quote:
Originally Posted by Bill Fitzmaurice View Post

The main thing is to test all in the same fashion. If you want to run the speaker at a specified SPL output for an hour to heat the coil and the run the THD test, fine. If you want to run it with the coil at room temperature, fine. Just do it the same for all tested speakers. If the intent is to see how they compare at reference run them at reference to warm them up, then test them at reference.
Absolutely. This would be great data to have.

It's one of the uses of Stereophile... they have measurements taken the same way for a lot of speakers.
post #521 of 820
Quote:
Originally Posted by Bill Fitzmaurice View Post

With HomlImpulse you don't have to do anything but measure. It gives FR, THD and phase on the same chart. You can turn off any of the displayed charts, and I always do with phase, unless that's what I want to see, as having all three displayed makes for a very busy chart. THD can be toggled to show total THD or any of the sub components, 2nd through 10th harmonic. I wouldn't be concerned over peaks, what you're interested in is what the speaker does at normal listening levels. Of course normal will be a lot different for MK than the rest of us.
Mine was mostly at 0.5% at what I would consider a loud but reasonable listening level.

At "cover my ears to test" it was 1.0% with peaks around 200Hz at 5% (I tested from 50Hz-20Khz).

How do others compare I wonder?
post #522 of 820
I have a 24" iMac, not a WinTel machine, REW works on my computer but HolmImpulse does not work on Mac's, so I'll try same with REW.

Besides just listing your result is the graph easily readable?

Please all post them to share!


Sent from my 32GB iPhone4 using Tapatalk
post #523 of 820
Thread Starter 
Quote:
Originally Posted by JerryLove View Post

Mine was mostly at 0.5% at what I would consider a loud but reasonable listening level.
At "cover my ears to test" it was 1.0% with peaks around 200Hz at 5% (I tested from 50Hz-20Khz).
How do others compare I wonder?
Since "loud" and "reasonable" are such subjective terms, what was the calibrated level you were listening at?
post #524 of 820
He also measured at the speaker.
post #525 of 820
Quote:
Originally Posted by Eyleron View Post

Since "loud" and "reasonable" are such subjective terms, what was the calibrated level you were listening at?
I don't know. I didn't have a db meter handy; and the mic cannot be trusted for absolute SPL because I don't have the input level calibrated.

Important to me (though perhaps no one else) is that they were "high listening level" and "above listening level" for my listening. In the end: knowing how my speakers perform above a volume I'd actually listen is an acedemic rather than practical question.

I would assert that I'm still ahead of the game having put up *something*.

I will see if I can get my hands on a db meter and run again. I'll also see if I can run on my two bigger sets. I'll also see if I can't bring the graphs over to this PC to post: though I have no ETA for all this.
Quote:
He also measured at the speaker.

I did measure at 1m, though I do sit at 2-3m for listening. The "loud" and "too loud" was at seating position; but obviously when I put up an actual db, the distance would matter.
Edited by JerryLove - 12/10/12 at 7:42pm
post #526 of 820
Thread Starter 
It's very important, because it's common around here to hear from people saying things like: "95db peaks, -10dbFS, seemed so LOUD before! Any louder would make me wince. My wife would leave the room. Now, with these new speakers, I naturally turn movies up to -2 and music I've had at +2 and it sounds so 'live' yet not as loud as before. Oh...and my wife now says, 'Baby, turn it UP.'"

Illustrates how we can easily conflate pain or unpleasant due to distortion with that of undistorted high SPL.
post #527 of 820
Quote:
Originally Posted by Eyleron View Post

It's very important, because it's common around here to hear from people saying things like: "95db peaks, -10dbFS, seemed so LOUD before! Any louder would make me wince. My wife would leave the room. Now, with these new speakers, I naturally turn movies up to -2 and music I've had at +2 and it sounds so 'live' yet not as loud as before. Oh...and my wife now says, 'Baby, turn it UP.'"
Illustrates how we can easily conflate pain or unpleasant due to distortion with that of undistorted high SPL.

Sure.

Except that we just got a real number on the distortion.

So if you think 1% distortion is causing me to wince from the distortion then you would have an excellent point.
If you think 1% isn't enough to cause that then the reason it's the highest I listen (actually: that's 0.5%) is because it's the loudest I like; not because of distortion.

To have any real objective meaning to others: we need to know SPL. I agree. I simply don't have that data or I'd share it. But to determine if these speakers meet my needs; the distortion at listening level should be enough to tell if I would be served by a hypothetical lower-distortion higher SPL speaker. I see no indication that I would.

In some other room where I need more SPL, I would need more speaker (as the "too loud" is playing with mechanical clipping on the mids without a subwoofer to eat the LF (I tested a couple of different ways and Freq ranges; the normal listening was clip-free with the speaker being fed full range, as was "too loud" with an 80Hz sub or with a sweep from 80Hz up rather than 50Hz up)

If I get my hands on an SPL meter (they are cheap) I'll get real numbers; and I'll also try my two "big" pairs, which are louder.

I guess what I'm saying is that these speakers: which are not particularly efficient nor power-capable, play as loud as I have any use for with very low distortion in a reasonably big space. Indeed: my biggest issue is LF, but that's why they make subs. These are not full range (the two big pair are both functionally full range)
Edited by JerryLove - 12/10/12 at 9:16pm
post #528 of 820
You need to measure at the LP so your THD is still meaningless. I measure my subs at 10hz, 15hz, and 20hz and it would have been much louder at the subs with the same THD. We never argued that if one listens to a lower level one can not use LS speakers, this thread is about reference levels which are 105 dBs at the seats. Unless you measure at the seats and run a 105 dBs sweep then measure THD all the work means nothing.
post #529 of 820
Quote:
Originally Posted by MKtheater View Post

You need to measure at the LP so your THD is still meaningless. I measure my subs at 10hz, 15hz, and 20hz and it would have been much louder at the subs with the same THD. We never argued that if one listens to a lower level one can not use LS speakers, this thread is about reference levels which are 105 dBs at the seats. Unless you measure at the seats and run a 105 dBs sweep then measure THD all the work means nothing.

No, the thread is about a list of speakers. That hasn't been discussed in many pages.

My involvement is centered around a response to a question followed by a dispute of facts.

The question was whether two speakers with different sensitivities, but also different power handling, such that the LS speaker was capable of the same SPL at the same or lower percentage of total power handling would sound the same.
I said that, hypothetically, it would.

Then Bill came in and started making some unsubstantiated (that HS is always lower distortion at a given SPL) and sometimes easily disprovable (that raising the sensitivity will lower the xmax for a given SPL and that xmax was the cause of all THD) claims which, I disputed and disproved.

Then there were a bunch of personal comments and questions about me. I didn't much respond to those because it's a juvenile and unproductive conversation. Then there was some name-calling from Bill.

Then there were a bunch of claims that those of us not using HS speakers were dealing with tremendous distortion (I'm dealing with 0.5% as measured at my listening levels) and that we didn't know what HS speakers sounded like (as though we've never sat in a movie theater, nor gone to a concert, nor a sporting event, nor heard a PA system). Again, I disputed.

I disproved pretty much every claim I've disputed by example, but had not with this one... so I took some LS speakers and played them at the level I care about and found very low distortion. Turns out I don't have a problem with distortion... which is what I had claimed. I've never claimed to some arbitrary SPL.

Yes. For it to have meaning for someone else it would need SPL. To do comparisons (and these are not the speakers I would chose for that unless the HS speakers they were compared to were very low max power) that's useless. To establish claims like the ones above about distortion at listening levels for the subjective listener (me): it's quite on-point.
Edited by JerryLove - 12/10/12 at 10:30pm
post #530 of 820
Quote:
Originally Posted by Eyleron View Post

It's very important, because it's common around here to hear from people saying things like: "95db peaks, -10dbFS, seemed so LOUD before! Any louder would make me wince. My wife would leave the room. Now, with these new speakers, I naturally turn movies up to -2 and music I've had at +2 and it sounds so 'live' yet not as loud as before. Oh...and my wife now says, 'Baby, turn it UP.'"
Illustrates how we can easily conflate pain or unpleasant due to distortion with that of undistorted high SPL.

Exactly. Hear it all the time. Super clean high SPL systems can be a bit dangerous since the listener doesn't hear distortion and can easily tolerate higher levels which may do hearing damage over time. Of course if kept at Reference and under it wouldn't at all dangerous.
post #531 of 820
Quote:
Originally Posted by Bill Fitzmaurice View Post

Measure at low power, measure at full power, and at a few spots in between. What you're really interested in is how much power the system will take before reaching 10% THD. That's your peak. And don't assume if THD is 10% or even higher that it won't sound good. Many's the audiophile willing to lay out big bucks for tube amps for their 'warmth'. Warmth is coloration, coloration is distortion.

Fascinating! Warmth = Coloration = Distortion

Is there an "audible" threshold for THD? Or does it vary per product and/or is subjective to an individuals ear?

I mean, if it's one thing I have learned from this thread, is that THD is present to some degree in all speakers. Just wondering if that 10% is the point where most of us would say, "Yeah, I can definitely hear the distortion."

Also, is it possible that one speaker could measure at 10% THD and be "audible/unacceptable" while another speaker could be playing at some 30% THD but be perceived as "inaudible/acceptable." Regardless of SPL, I am just trying to gauge how THD varies from speaker to speaker...
post #532 of 820
Quote:
Originally Posted by AV Science Sales 5 View Post

The problem between your comparison of sensitivity and the MPG on a new cars sticker is this:
The cars are measured in the same manner, so while the number may not reflect what you will actually get, the relationship between each car basically remains the same. With speaker sensitivity, it is not measured the same by every manufacturer. lets take for example a speaker that measures in a chamber 87db one watt per meter.
if that speaker is a 4ohm speaker a manufacture could list it as 90 watts per 2.81 volts.
Another manufacturer could use in room measurement and list the speaker as 94db one watt,2.81 volts.
Now we are talking about the same speaker, but showing 7db difference. Some manufacturers measure using two speakers and some corner load a speaker. So without knowing exactly how the measurement was taken, listing sensitivity means very little.

Hence the reason why testing, such as Ricci's @ Data Bass, is such a valuable resource! Objective and consistent!

I don't want to start a flame war, but how does something like THX standards play into the mix? I tried to do a quick search, but could not find the testing parameters behind how a speaker becomes "THX Certified." I understand they are supposed to play @ reference level, but does a THX certification ensure all equipment is measured on a consistent level playing field? Or are manufactures still allowed to utilize their own testing methods, but simply pay to have their product carry the THX Certification? I'm fully aware that there are HUNDREDS of products that greatly exceed whatever threshold is required to obtain a THX Certification.

Wait, when I put this in the perspective of audio/speakers, it appears as though THX is just a minimum requirement. If companies are willing to pay for the THX certification, it's either a pass/fail. You get the sticker, or not, correct?

Is there any other website, such as Ricci's, that put's speakers through the ringer of consistent objective measurements for all products?
post #533 of 820
Thread Starter 
Quote:
Originally Posted by popalock View Post


Fascinating! Warmth = Coloration = Distortion
Is there an "audible" threshold for THD? Or does it vary per product and/or is subjective to an individuals ear?
I mean, if it's one thing I have learned from this thread, is that THD is present to some degree in all speakers. Just wondering if that 10% is the point where most of us would say, "Yeah, I can definitely hear the distortion."
Also, is it possible that one speaker could measure at 10% THD and be "audible/unacceptable" while another speaker could be playing at some 30% THD but be perceived as "inaudible/acceptable." Regardless of SPL, I am just trying to gauge how THD varies from speaker to speaker...

Yeah, I, too, am interested in that 10% threshold. I am still reading the great PDF JerryLove linked about measuring distortion in speakers.

 

I do know that there are different types of distortion. Distortion products that are "even-order" are multiples of the frequency being played. Since these are octave increases, it's still the same "note," just higher; e.g. a middle-C instead in addition to a low-C note. While this is still distortion (what comes out differs from what goes in), it is not unpleasant and tube fans actually seek it out, which Bill was talking about earlier.

 

Odd-order distortion is grating.

 

Also, high-order distortion are peaks much higher in the frequency range (can be odd or even), so they may not be masked by the intended sounds.

Our sensitivity to and the audibility of distortion also varies by frequency. For instance, we tolerate much higher distortion in the bottom octave.

I think the PDF made a distinction that the distortion they were talking about didn't include a change in output or level. But from one standpoint, if you don't get the intended output changes due to compression or some other effect, or the frequency response tilts because the mid-bass can't keep up with the tweeter, that's a form of distortion. It may not be grating, but it might get more treble-heavy, for instance.

 

In short, THD doesn't paint the full picture of what sort of bad things the speaker is doing. But 1% distortion is probably inaudible and the best speakers probably produce that much distortion, not to mention the room itself imparting much more of that if you include frequency response changes due to super-position phase combining and cancellation of multiple speakers and reflections.

 

I'm interested to learn whether 8% even-low-order is audible and if 5% 3rd order is unpleasant.

post #534 of 820
Thread Starter 
Quote:
Originally Posted by JerryLove View Post
So if you think 1% distortion is causing me to wince from the distortion then you would have an excellent point...
If you think 1% isn't enough to cause that then the reason it's the highest I listen (actually: that's 0.5%) is because it's the loudest I like; not because of distortion.

Well, I mean that when you say that was the threshold of reasonable and loud, I imagine that above that, it was "too-loud" and "unreasonably loud."

And that could be 10%, or 30% distortion.

 

What I found in my home when testing last year Paradigm Titan v3 speakers, with lowish sensitivity of 86dB ancehoic and power handling around what my amp can produce, is as I raised the output level of a sine-wave, distortion would skyrocket around the level I considered wince-inducing.

 

Any higher than low-90s dB from listening position, and it starts to sound bad. Theoretically, that's where two things are happening:

  1. The output of the receiver is perhaps maxing out (debateable on peaks by 3dB or 2x power, since I'm not sure if its power supply can provide 3dB peak output over 500ms transients...but on a long-term signal like I was testing with, it's definitely limited by the RMS of the receiver).

    So, maybe I was inducing clipping at that point.
     
  2. However many watts I need to provide to get to, say, 94dB continuous, is around how many the speaker is rated to take, according to the manufacturer.

 

This review (which might be for v2 of the same speaker) talks about short bursts of more power without audible distortion, whatever that means.

 

Anyway, I may have been clipping the amp, or reached the limits of the RMS power handling of the speaker at that test frequency. Sine waves which have a 3dB crest factor (so not much varying of output level and thus no chance to cool down) are a lot more brutal than program material.

 

So, that's my personal anecdote of how 1dB increases of volume yielded rapid increases of distortion, when I was on the threshold of the system's capability. I need headroom, because I'd like to play louder with more dynamics.

post #535 of 820
Thread Starter 
Quote:
Originally Posted by popalock View Post
Is there any other website, such as Ricci's, that put's speakers through the ringer of consistent objective measurements for all products?

I looked at some recent Audioholic speaker reviews, and sometimes there was no FR graph. When there was, it was not at a high drive level.

 

The closest thing I know of, and what everyone else mentions, are the Stereophile reviews. They had more measurements, and they reported distortion at 90-something dB.

That's better than 1w of drive. And maybe 92dB or whatever it is RMS is enough to yield reference level peaks. Or maybe it's not.

 

So, we're back to how we need tests more comprehensive like Audioholics is doing with subs.

post #536 of 820
Quote:
Originally Posted by Eyleron View Post

Well, I mean that when you say that was the threshold of reasonable and loud, I imagine that above that, it was "too-loud" and "unreasonably loud."
And that could be 10%, or 30% distortion.
There's the rub. 'Distortion' doesn't automatically mean it sounds bad. Harmonic distortion is simply the presence of harmonics in the output not present in the input. A typical electric guitar amp/speaker will run with at least 20% THD. One through a fuzz box may be at 200% THD or more. Where the distortion takes place is even more important than how much. Added harmonics in the mids usually result in what's called 'warmth'. Added harmonics in the highs are usually perceived as harsh; not coincidentally that's why electric guitar speakers typically only reach at best to 5kHz and never use tweeters. High THD in subs results in above bandwidth content that would make most of us cringe when watching a DVD or listening to a CD, yet those harmonics can give what DJs call 'punch'.
The main reason for the 10% spec for speakers is that once 10% is reached the drivers are usually at their excursion limits, and any higher power input will make them non-linear.
post #537 of 820
Quote:
Originally Posted by JerryLove View Post

No, the thread is about a list of speakers. That hasn't been discussed in many pages.
My involvement is centered around a response to a question followed by a dispute of facts.
The question was whether two speakers with different sensitivities, but also different power handling, such that the LS speaker was capable of the same SPL at the same or lower percentage of total power handling would sound the same.
I said that, hypothetically, it would.
Then Bill came in and started making some unsubstantiated (that HS is always lower distortion at a given SPL) and sometimes easily disprovable (that raising the sensitivity will lower the xmax for a given SPL and that xmax was the cause of all THD) claims which, I disputed and disproved.
Then there were a bunch of personal comments and questions about me. I didn't much respond to those because it's a juvenile and unproductive conversation. Then there was some name-calling from Bill.
Then there were a bunch of claims that those of us not using HS speakers were dealing with tremendous distortion (I'm dealing with 0.5% as measured at my listening levels) and that we didn't know what HS speakers sounded like (as though we've never sat in a movie theater, nor gone to a concert, nor a sporting event, nor heard a PA system). Again, I disputed.
I disproved pretty much every claim I've disputed by example, but had not with this one... so I took some LS speakers and played them at the level I care about and found very low distortion. Turns out I don't have a problem with distortion... which is what I had claimed. I've never claimed to some arbitrary SPL.
Yes. For it to have meaning for someone else it would need SPL. To do comparisons (and these are not the speakers I would chose for that unless the HS speakers they were compared to were very low max power) that's useless. To establish claims like the ones above about distortion at listening levels for the subjective listener (me): it's quite on-point.

I have always been about what ever sounds best to the individual. I also just post my experiences and what I love someone else might hate. It is OK because if we were all the same it would be boring. People always make subjective comments(I do too) and say a certain speaker is better than other for some reason or another but I always wonder why, maybe we like different distortion levels, different response, etc.... I will measure tonight like I did my subs but at 115 dBs from 30hz-80hz(subs) and at 105 dBs at 200hz, 500hz, 1Khz, 2khz, 4khz, 8khz, and 16khz just to see what it is at my LP. According to all the specs and math I should be using no more than 4-16 watts. Here are what my initial graphs of my subs looked like.







post #538 of 820
Quote:
Originally Posted by JerryLove View Post

Absolutely. This would be great data to have.
It's one of the uses of Stereophile... they have measurements taken the same way for a lot of speakers.

For sure Ive always applauded Stereophile for doing that.
post #539 of 820
yes, John Atkinson is probably the only remaining reason to read loudspeaker reviews in Stereophile

Measuring Loudspeakers, Part One
Measuring Loudspeakers, Part Two
Measuring Loudspeakers, Part Three

re: sensitivity
Quote:
What is a typical loudspeaker sensitivity? Fig.1 tabulates the calculated B-weighted sensitivities for 261 of the loudspeakers reviewed in Stereophile between January 1991 and June 1997. The mean measured sensitivity is 88dB(B)/2.83V/m; the median is 85dB(B). Almost 40% of the models measured had B-weighted sensitivities falling between 84.5dB and 87.4dB. The distribution seems roughly "Normal," with only a few models falling below 80dB(B) or above 90dB(B). The low-sensitivity models tend to be panel speakers of various kinds, while all the speakers of 95dB(B) sensitivity or higher are professional monitors (and one musical instrument speaker measured for curiosity's sake).

Fig.1 261 loudspeakers, B-weighted voltage sensitivities.

The relatively narrow spread of sensitivities should not come as a surprise. To achieve a high sensitivity requires heroic engineering, which will always be expensive. All speaker designers are constrained by budget constraints, which in turn mean that they will tend to settle on similar compromises involving magnet size, voice-coil design, and cone area.

In general, my measured sensitivities are slightly low compared with those published by the speakers' manufacturers. Mostly, I believe this is due to the optimistic nature of published sensitivity specifications.

Re: Harmonic Distortion
Quote:
There is considerable discussion in the literature of nonlinear (harmonic) distortion in loudspeaker behavior [46, 47, 48]. All loudspeakers have nonlinear distortion, and small, inexpensive loudspeakers tend to have more nonlinear distortion than large, expensive loudspeakers. Perversely, I don't think this is that important a factor in loudspeaker performance. I have measured loudspeaker harmonic distortion spectra when listening tests had suggested that it was unusually high or low [49, 50]. I have also investigated distortion when I have found a loudspeaker producing audible sub-harmonics, tones whose frequencies are an integral fraction, one half, one third, one quarter, of the fundamental [51]. In a presentation at the 1989 Audio Engineering Society Convention in New York, the mathematician Manfred Schroeder postulated that the production of subharmonics is often related to the presence of chaotic behavior in a diaphragm. This latter phenomenon can be heard on Stereophile's Test CD 2, Track 25.

But of all the loudspeakers that have been reviewed in Stereophile in the past eight years, there are only a few in which noticeable levels of harmonic distortion have been associated with negative review findings. However, I do conjecture that listeners use overall distortion to set a comfortable playback level. If a loudspeaker has high intrinsic distortion, hence a limited dynamic range, it won't be played as loud. Once the level of harmonic distortion rises above a threshold (probably one that is different for each listener), the listener reaches for the volume-control knob. I realize, of course, that my opinions on this subject will be controversial.
post #540 of 820
here is a collection of papers on the subject of Distortion Perception from Dr. Geddes

http://www.gedlee.com/distortion_perception.htm

most of the stuff there is well over my head.

He discusses the issue in more accessible terms in this interview.

http://www.dagogo.com/View-Article.asp?hArticle=1047

Geddes does not believe that THD is useful metric for evaluating loudspeakers. According to him, low order harmonics even at high levels do not sound bad as long as the driver operate within its design limits (I think that's also what Bill said a few posts back).
Geddes is more concerned with nonlinear distortions in electronics and crossovers. in his opinion those matter even at low levels.
And of course there is his pet peeve, the Higher Order Modes or HOMs.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Speakers
AVS › AVS Forum › Audio › Speakers › List of Reference Level, High Sensitivity & SPL Speakers