MLs lose 3db while point sources lose 6db per doubling of distance
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tonepub
Senior Member
What do you mean, you pair your ml's with "helper" speakers?
Never heard of that one...
Never heard of that one...
That's not the issue though*
What they say here is that point sources attenuate at a much faster rate than line sources.
So despite getting identical db measurements at the listening position, the panels 'fill' the room much better and this can be measured.
It could be the explanation behind the wide-ranging opinions on the bass of MLs in general. Some people swear that they are bass-shy, some that they are bass-heavy and flabby, others that they are perfect. All this controversy comes from experienced audiophiles, too. Room acoustics are obviously a major factor, but why would the same speaker placed optimally (ahem!) in a smaller room sound so different in the low frequencies? Much different than box speakers would sound (accounting for standing waves etc)
The explanation here is that the panel element of the MLs attenuates at a much lower rate compared to the woofer element, so you could have a perfect balance in a room, but in a larger room the panel would overwhelm because low frequencies come from a point source that loses energy quicker.
So at double the 'optimal' distance, low frequencies will be -3db, sounding bass-shy. Double that again and you lose another 3db relative to the panel, wondering where all the bass has gone.
This would not be the case with box speakers, where all drivers are point sources.
I remember the Stereophile review of the SL3 mentioned the difficulty in measuring them accurately (compared to conventional speakers) so there might be something in this line/point source theory
* I mean use 'box' speakers in conjuction so that mid-bass and lows are dynamic and musical. The MLs measure flat, but playing rock they fall flat on their faces, can't punch. With acoustic instruments, voice etc the MLs are perfect on their own, don't get me wrong. It also depends heavily on the room, etc.
What they say here is that point sources attenuate at a much faster rate than line sources.
So despite getting identical db measurements at the listening position, the panels 'fill' the room much better and this can be measured.
It could be the explanation behind the wide-ranging opinions on the bass of MLs in general. Some people swear that they are bass-shy, some that they are bass-heavy and flabby, others that they are perfect. All this controversy comes from experienced audiophiles, too. Room acoustics are obviously a major factor, but why would the same speaker placed optimally (ahem!) in a smaller room sound so different in the low frequencies? Much different than box speakers would sound (accounting for standing waves etc)
The explanation here is that the panel element of the MLs attenuates at a much lower rate compared to the woofer element, so you could have a perfect balance in a room, but in a larger room the panel would overwhelm because low frequencies come from a point source that loses energy quicker.
So at double the 'optimal' distance, low frequencies will be -3db, sounding bass-shy. Double that again and you lose another 3db relative to the panel, wondering where all the bass has gone.
This would not be the case with box speakers, where all drivers are point sources.
I remember the Stereophile review of the SL3 mentioned the difficulty in measuring them accurately (compared to conventional speakers) so there might be something in this line/point source theory
* I mean use 'box' speakers in conjuction so that mid-bass and lows are dynamic and musical. The MLs measure flat, but playing rock they fall flat on their faces, can't punch. With acoustic instruments, voice etc the MLs are perfect on their own, don't get me wrong. It also depends heavily on the room, etc.
Bernard
Well-known member
I'm missing somethng basic here: once the air is set in motion why does it matter what the source was ? Attenuation through air should be the same for both.
tonepub
Senior Member
If you want to rock, you need a pair of Summits and a Descent. That rocks just fine.
JohnA
I’ve been harping on this one for a couple of years as the root of the concern over hybrid ESL ‘integration’ issues.
More than low-bass, the critical mid-bass region (which I define as 80 to 500hz) is the one that suffers in hybrid ESL designs that use a single point-source woofer for parts of that range. First challenge is that you have a crossover element in that region, which can (and does) introduce phase integration issues. Couple that with the variance between line-source and point-source radiation in the 120 to 400hz region, and it’s no wonder it’s a hit-or-miss setup/room combo that results in either good or unsatisfactory sound from them.
As I expound on in the intro to my mid-bass line array design the key challenge is that these frequencies are critical to getting an ‘integrated’ and balanced sound from the system at varying power levels. Something I’ve been referring to as the ‘power curve’ of the speaker.
Often a speaker will sound balanced at 80dB and totally anemic (in the mid-bass) at 90dB, a big part of that is the difference between line-source radiation of the ESL and point source radiation of the dynamic woofer.
However, there is a correlation to line source length on how low in frequency this near-field vs far-field effect goes. For a 4’ line source, it’s in the 250hz range. For an 8’ line source it can go down to 100hz.
Therefore some of this is academic, from a point-source vs line-source standpoint, as bass in general will obey point source rules from an SPL standpoint. However, this is mitigated by the fact that bass is reinforced quite substantially in a small enclosed area. Some of that is good, some is bad (room modes).
My experience is that a mid-bass array goes a long way to addressing some of the challenges of integration between dynamic speakers and the ESL.
One of the reasons is you remove the dipole rear wave cancelation effect by moving more of the mid-bas to the dynamic speaker array. The other is the greatly enhanced low-distortion capability multiple dynamic drives in the mid-bass gives.
I find it also helps ‘normalize’ some of the reverberant issues in the mid-bass, by energizing the room at those frequencies across a longer length in the vertical dimension. I comment a bit on that in this other post.
For more background and theory on Line source speakers, please read Dr. James Griffin paper: http://www.audiodiycentral.com/resource/pdf/nflawp.pdf
I’ve been harping on this one for a couple of years as the root of the concern over hybrid ESL ‘integration’ issues.
More than low-bass, the critical mid-bass region (which I define as 80 to 500hz) is the one that suffers in hybrid ESL designs that use a single point-source woofer for parts of that range. First challenge is that you have a crossover element in that region, which can (and does) introduce phase integration issues. Couple that with the variance between line-source and point-source radiation in the 120 to 400hz region, and it’s no wonder it’s a hit-or-miss setup/room combo that results in either good or unsatisfactory sound from them.
As I expound on in the intro to my mid-bass line array design the key challenge is that these frequencies are critical to getting an ‘integrated’ and balanced sound from the system at varying power levels. Something I’ve been referring to as the ‘power curve’ of the speaker.
Often a speaker will sound balanced at 80dB and totally anemic (in the mid-bass) at 90dB, a big part of that is the difference between line-source radiation of the ESL and point source radiation of the dynamic woofer.
However, there is a correlation to line source length on how low in frequency this near-field vs far-field effect goes. For a 4’ line source, it’s in the 250hz range. For an 8’ line source it can go down to 100hz.
Therefore some of this is academic, from a point-source vs line-source standpoint, as bass in general will obey point source rules from an SPL standpoint. However, this is mitigated by the fact that bass is reinforced quite substantially in a small enclosed area. Some of that is good, some is bad (room modes).
My experience is that a mid-bass array goes a long way to addressing some of the challenges of integration between dynamic speakers and the ESL.
One of the reasons is you remove the dipole rear wave cancelation effect by moving more of the mid-bas to the dynamic speaker array. The other is the greatly enhanced low-distortion capability multiple dynamic drives in the mid-bass gives.
I find it also helps ‘normalize’ some of the reverberant issues in the mid-bass, by energizing the room at those frequencies across a longer length in the vertical dimension. I comment a bit on that in this other post.
For more background and theory on Line source speakers, please read Dr. James Griffin paper: http://www.audiodiycentral.com/resource/pdf/nflawp.pdf
Probably the line source activates many more molecules than the point source.
If we are using a dbmeter we are favouring the point source, because we ignore the many more activated air molecules from the line source.
Bit like looking at a 2-D version of a 3-D shape.
So the line source dumps a lot more energy in the room at the same db (measured at a specific point in the room).
That's my take anyway
I'll read up a bit of Jonathan's stuff and see what's up I posted this because it tickled my interest, that's all.
Yep, I've seen this a lot.
The funny thing is that it measures flat both at 80db and 90db, but you just feel that at 90db it has dropped the ball. So it must be something the dbmeter can't catch.
That's why I feel I need to use a pair of box speakers on the side of the MLs as well as two subs in a room that isn't that big.
At higher volumes it just feels anaemic with jazz/rock and just the logans. Gutless.
At lower volumes it's not an issue.
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Audioseduction
Well-known member
Interesting paper - and relevant here too
According to it, the 3db attenuation with the panels is more due to the listener being nearfield - where if they were point sources it would have been far-field (which is 6db/doubling of distance)
I was actually wondering about this, attenuation mentioned as 3db/doubling in some sources and 6db in others, with no explanation which witch is which.
Near/Far field explains it, they can all be correct (depending on context of course)
