PS1 Powerstand Bass - Revision history

ST: ® replaces ™ {{:L1® vs B1 Bass Module Fall Off with Distance}}

2008-03-15T15:47:57Z

® replaces ™ {{:L1® vs B1 Bass Module Fall Off with Distance}}

← Older revision		Revision as of 15:47, 15 March 2008
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	== {{L1}} versus {{B1}} fall-off with distance ==		== {{L1}} versus {{B1}} fall-off with distance ==
	{{:~~L1™~~ vs B1 Bass Module Fall Off with Distance}}		{{:L1® vs B1 Bass Module Fall Off with Distance}}

	<!--		<!--

ST: Category:A1 PackLite®

2007-06-19T18:19:24Z

Category:A1 PackLite®

← Older revision		Revision as of 18:19, 19 June 2007
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	<references/>		<references/>

	[[Category:A1 ~~PackLite™~~]]		[[Category:A1 PackLite®]]
	[[Category:PS1 Powerstand]]		[[Category:PS1 Powerstand]]
	[[Category:Bass]]		[[Category:Bass]]
	[[Category:B1 Bass Module]]		[[Category:B1 Bass Module]]

ST: PackLite® power amplifier Model A1

2007-06-19T18:09:50Z

PackLite® power amplifier Model A1

← Older revision		Revision as of 18:09, 19 June 2007
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	{\| style="color:black;background-color:WhiteSmoke;" cellpadding="20" cellspacing="0" border="0"		{\| style="color:black;background-color:WhiteSmoke;" cellpadding="20" cellspacing="0" border="0"
	\|__TOC__		\|__TOC__
	\|Hilmar-at-Bose wrote this great reference for the [[A1 ~~PackLite™~~]] in the Bose Musicians Forum <ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/2641067362#2641067362 original discussion - A1 PackLite Questions and More Bass Talk]</ref>.		\|Hilmar-at-Bose wrote this great reference for the [[PackLite® power amplifier Model A1]] in the Bose Musicians Forum <ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/2641067362#2641067362 original discussion - A1 PackLite Questions and More Bass Talk]</ref>.
	<br />This covers		<br />This covers
	* the behaviour of the crossover in the {{L1}}		* the behaviour of the crossover in the {{L1}}

ST: transcluded {{:L1™ vs B1 Bass Module Fall Off with Distance}}

2006-12-29T09:01:25Z

transcluded {{:L1™ vs B1 Bass Module Fall Off with Distance}}

← Older revision		Revision as of 09:01, 29 December 2006
Line 50:		Line 50:
	As a rule-of-thumb guideline, turn the bass up a notch as you turn the volume down.		As a rule-of-thumb guideline, turn the bass up a notch as you turn the volume down.

	~~The following appeared in a separate post]<ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/6031049362#6031049362 second post - A1 PackLite Questions and More Bass Talk]</ref>.~~

	== {{L1}} versus {{B1}} fall-off with distance ==		== {{L1}} versus {{B1}} fall-off with distance ==
	~~As many have observed, only the {{L1}} qualifies as a Cylindrical Radiator™ loudspeaker, the~~ {{B1~~}} certainly doesn’t as it looks a lot more like “cubical” radiator. Only a cylindrical source will display 3 dB per distance-doubling falloff. The B1 is a conventional speaker and falls off~~ with ~~6 dB per distance-doubling. Does that mean that the spectrum gets unbalanced with distance, i.e. not enough bass as we move away from the source?~~		{{:L1™ vs B1 Bass Module Fall Off with Distance}}

	Not really, and here is why: The observation of so-and-so dB per distance doubling is only true in “free field”, i.e. in some imaginary space that doesn’t have any reflective surfaces. Such a thing doesn’t exist. Most places where you play generate lots and lots of reflections. At any point in the room, the sound field consists of two components:
	~~# The sound that comes directly from the source aptly called “direct sound” and~~
	~~# All the sound that comes bouncing back from the walls, called “[[Reverberant Field\|reverberant field]]”.~~

	The level of the [[Reverberant Field\|reverberant field]] tends to be roughly the same everywhere in the room. When you are close to the source, the “direct sound” dominates. As you move away from the source, the direct sound drops in level and at some point called [[Critical Distance\|critical distance]] the direct sound has the same level as the reverberant field. From this point on the [[Reverberant Field\|reverberant field]] dominates and the sound level remains pretty much constant no matter how much further you move away.

	The level of the [[Reverberant Field\|reverberant field]], the [[Critical Distance\|critical distance]], and the “reverb time” are all close room acoustical cousins and basically determined by the geometry and amount of absorption of the room. In nearly all rooms, there is more absorption at high frequencies and less absorption at low frequencies. Less absorption makes the reverb time longer, the reverberant field level higher, and the critical distance shorter.

	Another factor that influences the [[Critical Distance\|critical distance]] is the directivity of the sound source. Let’s make a thought experiment: Imagine a sound source that radiates “normally” to the front but nothing to the back. The direct sound level doesn’t change, but the reverberant level drops by 3 dB since the total energy radiated into the room has dropped by half. That means the critical distance has increased. Of course, that’s only true if you stand in front of the source. In the rear, there is no direct sound any more and the critical distance has become zero. We see that the directionality of the sound source increases the critical distance within it’s beam, cone, pie slice (or whatever shape it radiates), but decreases the critical distance outside.

	Now what has all that to do with our initial L1/B1 problem? As it turns out the {{L1}} has a much higher critical distance than the {{B1}}. That has two reasons: First, there is more absorption at higher frequencies. Second, the {{L1}} is highly directional: it doesn’t radiate up or down.

	Taking all this together we see roughly the following picture: The {{L1}} has a fairly large critical distance, i.e. it’s mostly direct sound and that falls off with ca. 3 dB per distance doubling. The {{B1}} has a short critical distance (not directional, low room absorption) so the behavior becomes quickly a mix of reverberant field and direct sound which tends to also look fairly similar to a 3 dB per distance-doubling fall-off over a good stretch.

	To add insult to injury, this is all grossly simplified. In actual rooms, the reverberant field is never really constant, room modes get in the way, the L1 behaves not quite cylindrical in the lower mids, bass levels increase in the vicinity of wall, etc.

	~~If it’s any consolation, we have actually measured the fall off versus distance for our combined system ({{L1}} & {{B1~~}}~~) in a couple of different rooms and the 3 dB per distance-doubling describes the measured data remarkably well.~~

			<!--
	If anyone is still awake after this lengthy lecture (apologies), I’ll try to tackle the “philosophical” stuff next.		If anyone is still awake after this lengthy lecture (apologies), I’ll try to tackle the “philosophical” stuff next.
			-->
	Hilmar		Hilmar

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	<references/>		<references/>

	[[~~category~~:A1 PackLite™]]		[[Category:A1 PackLite™]]
	[[~~category~~:PS1 Powerstand]]		[[Category:PS1 Powerstand]]
	[[~~category~~:Bass]]		[[Category:Bass]]
	[[~~category~~:B1 Bass Module]]		[[Category:B1 Bass Module]]

ST: /* L1 versus B1 fall-off with distance */ critical distance

2006-12-29T08:53:52Z

L1 versus B1 fall-off with distance: critical distance

ST: introduction

2006-11-18T01:28:30Z

introduction

← Older revision		Revision as of 01:28, 18 November 2006
Line 1:		Line 1:
	Hilmar-at-Bose wrote this great reference for the [[A1 PackLite™]] in the Bose Musicians Forum <ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/2641067362#2641067362 original discussion - A1 PackLite Questions and More Bass Talk]</ref>		{\| style="color:black;background-color:WhiteSmoke;" cellpadding="20" cellspacing="0" border="0"
			\|__TOC__
			\|Hilmar-at-Bose wrote this great reference for the [[A1 PackLite™]] in the Bose Musicians Forum <ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/2641067362#2641067362 original discussion - A1 PackLite Questions and More Bass Talk]</ref>.
			<br />This covers
			* the behaviour of the crossover in the {{L1}}
			* what happens with one or two {{B1}}s,
			* outputs from the Bass Line-Out, and
			* interaction with the {{A1}}.
			\|-
			\|
			\|
			\|}

	Let’s start with some technical stuff (philosophy will be in the next installment)		Let’s start with some technical stuff (philosophy will be in the next installment).

	== Crossover ==		== Crossover ==

ST: /* Without Bass Line out */ revert back - L1™ discussed in previous paragraph

2006-11-18T01:09:13Z

Without Bass Line out: revert back - L1™ discussed in previous paragraph

← Older revision		Revision as of 01:09, 18 November 2006
Line 12:		Line 12:

	=== Without Bass Line out ===		=== Without Bass Line out ===
	* 0xB1: L1™ 110 Hz and up.
	* 1xB1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB		* 1xB1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB
	* 2xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal		* 2xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal

ST: /* Without Bass Line out */ L1&trade with no B1

2006-11-17T18:05:38Z

Without Bass Line out: L1&trade with no B1

← Older revision		Revision as of 18:05, 17 November 2006
Line 12:		Line 12:

	=== Without Bass Line out ===		=== Without Bass Line out ===
			* 0xB1: L1™ 110 Hz and up.
	* 1xB1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB		* 1xB1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB
	* 2xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal		* 2xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal

ST: category:A1 PackLite™

2006-08-23T12:52:00Z

category:A1 PackLite™

← Older revision		Revision as of 12:52, 23 August 2006
Line 69:		Line 69:
	<references/>		<references/>

			[[category:A1 PackLite™]]
	[[category:PS1 Powerstand]]		[[category:PS1 Powerstand]]
	[[category:Bass]]		[[category:Bass]]
	[[category:B1 Bass Module]]		[[category:B1 Bass Module]]

ST: first edition

2006-08-21T23:18:22Z

first edition

New page

Hilmar-at-Bose wrote this great reference for the [[A1 PackLite™]] in the Bose Musicians Forum <ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/2641067362#2641067362 original discussion - A1 PackLite Questions and More Bass Talk]</ref>

Let’s start with some technical stuff (philosophy will be in the next installment)

== Crossover ==
If there is no B1 and nothing connected to the Bass Line Out. The L1 sees frequencies from 110Hz up. Feeding it anything lower, doesn’t make sense, since it couldn’t produce any acoustic output and if would rip the drivers to shreds.

In any other case the L1 sees signals only from 180Hz up. There is no other variation in frequency or gain for the L1 no matter what else happens

== Bass Line Out and B1 behavior ==
This is based on the design goal that “You should always sound the same; no matter how much Bass stuff is attached” I can try to explain my view of why this is a good design goal (of which you may disagree) but let’s look at the actual behavior first.

=== Without Bass Line out ===
* 1xB1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB
* 2xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal

=== With Bass Line Out ===
* 0xB1: 40-180 Hz, flat, roughly the same gain as 2 B1
* 1xB1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal
* 2xB1: 40Hz-180Hz, B1 specific EQ, -12dB as compared to nominal

What this complex behavior does is the following. No matter if you attach 1, 2, or 4 B1s, you will get pretty much the same balance between all combined B1s and the L1s. It’s a little off for 3, 5, 6, 7 & 8 B1s, but still reasonably close.

== Frequency content of an acoustic guitar ==
Oldghm, you did some really interesting experiments there. However, you have to be really careful when using an RTA. You can feed these things a pure sine wave at 80 Hz and by turning it up make the 63 Hz and even the 40Hz LED light up. They will be lower than the 80 Hz LED, but still come on. That does NOT mean, that the sine wave contains any other frequency than 80 Hz (it certainly doesn’t). It only means that the RTA has a pretty limited frequency resolution. The 63 Hz LED will respond best to 63 Hz signal but it’s in no way “blind” to 80 Hz signal.
Thus being said, the actual frequency content is not easy to determine. All sounds that have a pitch are certainly constraint to 80 Hz and up (in standard tuning) and there isn’t actually too much energy at the fundamental. However, the “non-pitched” sounds like a hard string attack or whacking the top with your hand can very well have lower frequencies. Unfortunately, I don’t have any hard data on that, but we will measure that at some point.

== Equal loudness curves ==
Here is the bunch
[http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eqloud.html Equal Loudness Curves]
These curves tell us two things:
# First, the same physical sound energy produces different perceived loudness depending on frequency. You can turn that around into “The physical sound energy required to produce the same perceived loudness varies with frequency”.
# Second, this frequency dependency is a function of overall level.

The first statement is not particularly bothersome. Your auditory system is well calibrated to that. A voice sounds normal because it sounds like what you are used to, not because it has “constant sound energy” or “constant perceived loudness” with frequency.

The second statement is much more trouble. It basically says that if you amplify an acoustic source (even if you do it perfectly), the perceived spectral balance will change. This is a well known effect, and most of our home entertainment systems have actually and “automatic loudness compensation” that changes the system voicing with overall level. We actually contemplated adding this to the Personalized Amplification System™ but after some soul searching we thought it would be too intrusive on the musician.
The main corrections are at very low levels, and in most practical live music settings, the effect is pretty minor.
As a rule-of-thumb guideline, turn the bass up a notch as you turn the volume down.

The following appeared in a separate post]<ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/6031049362#6031049362 second post - A1 PackLite Questions and More Bass Talk]</ref>.

== L1 versus B1 fall-off with distance ==
As many have observed, only the L1 qualifies as a Cylindrical Radiator™ loudspeaker, the B1 certainly doesn’t as it looks a lot more like “cubical” radiator. Only a cylindrical source will display 3 dB per distance-doubling falloff. The B1 is a conventional speaker and falls off with 6 dB per distance-doubling. Does that mean that the spectrum gets unbalanced with distance, i.e. not enough bass as we move away from the source?

Not really, and here is why: The observation of so-and-so dB per distance doubling is only true in “free field”, i.e. in some imaginary space that doesn’t have any reflective surfaces. Such a thing doesn’t exist. Most places where you play generate lots and lots of reflections. At any point in the room, the sound field consists of two components: 1) The sound that comes directly from the source aptly called “direct sound” and 2) all the sound that comes bouncing back from the walls, called “reverberant field”.

The level of the reverberant field tends to be roughly the same everywhere in the room. When you are close to the source, the “direct sound” dominates. As you move away from the source, the direct sound drops in level and at some point called “critical distance” the direct sound has the same level as the reverberant field. From this point on the reverberant field dominates and the sound level remains pretty much constant no matter how much further you move away.

The level of the “reverberant field”, the “critical distance”, and the “reverb time” are all close room acoustical cousins and basically determined by the geometry and amount of absorption of the room. In nearly all rooms, there is more absorption at high frequencies and less absorption at low frequencies. Less absorption makes the reverb time longer, the reverberant field level higher, and the critical distance shorter.

Another factor that influences the critical distance is the directivity of the sound source. Let’s make a thought experiment: Imagine a sound source that radiates “normally” to the front but nothing to the back. The direct sound level doesn’t change, but the reverberant level drops by 3 dB since the total energy radiated into the room has dropped by half. That means the critical distance has increased. Of course, that’s only true if you stand in front of the source. In the rear, there is no direct sound any more and the critical distance has become zero. We see that the directionality of the sound source increases the critical distance within it’s beam, cone, pie slice (or whatever shape it radiates), but decreases the critical distance outside.

Now what has all that to do with our initial L1/B1 problem? As it turns out the L1 has a much higher critical distance than the B1. That has two reasons: First, there is more absorption at higher frequencies. Second, the L1 is highly directional: it doesn’t radiate up or down.

Taking all this together we see roughly the following picture: The L1 has a fairly large critical distance, i.e. it’s mostly direct sound and that falls off with ca. 3 dB per distance doubling. The B1 has a short critical distance (not directional, low room absorption) so the behavior becomes quickly a mix of reverberant field and direct sound which tends to also look fairly similar to a 3 dB per distance-doubling fall-off over a good stretch.

To add insult to injury, this is all grossly simplified. In actual rooms, the reverberant field is never really constant, room modes get in the way, the L1 behaves not quite cylindrical in the lower mids, bass levels increase in the vicinity of wall, etc.

If it’s any consolation, we have actually measured the fall off versus distance for our combined system (L1 & B1) in a couple of different rooms and the 3dB per distance- doubling describes the measured data remarkably well.

If anyone is still awake after this lengthy lecture (apologies), I’ll try to tackle the “philosophical” stuff next.

Hilmar

----
<references/>

[[category:PS1 Powerstand]]
[[category:Bass]]
[[category:B1 Bass Module]]

← Older revision		Revision as of 08:53, 29 December 2006
Line 52:		Line 52:
	The following appeared in a separate post]<ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/6031049362#6031049362 second post - A1 PackLite Questions and More Bass Talk]</ref>.		The following appeared in a separate post]<ref>[http://bose.infopop.cc/eve/forums/a/tpc/f/3976055944/m/6121039062/r/6031049362#6031049362 second post - A1 PackLite Questions and More Bass Talk]</ref>.

	== L1 versus B1 fall-off with distance ==		== {{L1}} versus {{B1}} fall-off with distance ==
	As many have observed, only the L1 qualifies as a Cylindrical Radiator™ loudspeaker, the B1 certainly doesn’t as it looks a lot more like “cubical” radiator. Only a cylindrical source will display 3 dB per distance-doubling falloff. The B1 is a conventional speaker and falls off with 6 dB per distance-doubling. Does that mean that the spectrum gets unbalanced with distance, i.e. not enough bass as we move away from the source?		As many have observed, only the {{L1}} qualifies as a Cylindrical Radiator™ loudspeaker, the {{B1}} certainly doesn’t as it looks a lot more like “cubical” radiator. Only a cylindrical source will display 3 dB per distance-doubling falloff. The B1 is a conventional speaker and falls off with 6 dB per distance-doubling. Does that mean that the spectrum gets unbalanced with distance, i.e. not enough bass as we move away from the source?

	Not really, and here is why: The observation of so-and-so dB per distance doubling is only true in “free field”, i.e. in some imaginary space that doesn’t have any reflective surfaces. Such a thing doesn’t exist. Most places where you play generate lots and lots of reflections. At any point in the room, the sound field consists of two components: 1) The sound that comes directly from the source aptly called “direct sound” and ~~2) all~~ the sound that comes bouncing back from the walls, called ~~“reverberant field”~~.		Not really, and here is why: The observation of so-and-so dB per distance doubling is only true in “free field”, i.e. in some imaginary space that doesn’t have any reflective surfaces. Such a thing doesn’t exist. Most places where you play generate lots and lots of reflections. At any point in the room, the sound field consists of two components:
			# The sound that comes directly from the source aptly called “direct sound” and
			# All the sound that comes bouncing back from the walls, called “[[Reverberant Field\|reverberant field]]”.

	The level of the reverberant field tends to be roughly the same everywhere in the room. When you are close to the source, the “direct sound” dominates. As you move away from the source, the direct sound drops in level and at some point called ~~“critical distance”~~ the direct sound has the same level as the reverberant field. From this point on the reverberant field dominates and the sound level remains pretty much constant no matter how much further you move away.		The level of the [[Reverberant Field\|reverberant field]] tends to be roughly the same everywhere in the room. When you are close to the source, the “direct sound” dominates. As you move away from the source, the direct sound drops in level and at some point called [[Critical Distance\|critical distance]] the direct sound has the same level as the reverberant field. From this point on the [[Reverberant Field\|reverberant field]] dominates and the sound level remains pretty much constant no matter how much further you move away.

	The level of the ~~“reverberant field”~~, the ~~“critical distance”~~, and the “reverb time” are all close room acoustical cousins and basically determined by the geometry and amount of absorption of the room. In nearly all rooms, there is more absorption at high frequencies and less absorption at low frequencies. Less absorption makes the reverb time longer, the reverberant field level higher, and the critical distance shorter.		The level of the [[Reverberant Field\|reverberant field]], the [[Critical Distance\|critical distance]], and the “reverb time” are all close room acoustical cousins and basically determined by the geometry and amount of absorption of the room. In nearly all rooms, there is more absorption at high frequencies and less absorption at low frequencies. Less absorption makes the reverb time longer, the reverberant field level higher, and the critical distance shorter.

	Another factor that influences the critical distance is the directivity of the sound source. Let’s make a thought experiment: Imagine a sound source that radiates “normally” to the front but nothing to the back. The direct sound level doesn’t change, but the reverberant level drops by 3 dB since the total energy radiated into the room has dropped by half. That means the critical distance has increased. Of course, that’s only true if you stand in front of the source. In the rear, there is no direct sound any more and the critical distance has become zero. We see that the directionality of the sound source increases the critical distance within it’s beam, cone, pie slice (or whatever shape it radiates), but decreases the critical distance outside.		Another factor that influences the [[Critical Distance\|critical distance]] is the directivity of the sound source. Let’s make a thought experiment: Imagine a sound source that radiates “normally” to the front but nothing to the back. The direct sound level doesn’t change, but the reverberant level drops by 3 dB since the total energy radiated into the room has dropped by half. That means the critical distance has increased. Of course, that’s only true if you stand in front of the source. In the rear, there is no direct sound any more and the critical distance has become zero. We see that the directionality of the sound source increases the critical distance within it’s beam, cone, pie slice (or whatever shape it radiates), but decreases the critical distance outside.

	Now what has all that to do with our initial L1/B1 problem? As it turns out the L1 has a much higher critical distance than the B1. That has two reasons: First, there is more absorption at higher frequencies. Second, the L1 is highly directional: it doesn’t radiate up or down.		Now what has all that to do with our initial L1/B1 problem? As it turns out the {{L1}} has a much higher critical distance than the {{B1}}. That has two reasons: First, there is more absorption at higher frequencies. Second, the {{L1}} is highly directional: it doesn’t radiate up or down.

	Taking all this together we see roughly the following picture: The L1 has a fairly large critical distance, i.e. it’s mostly direct sound and that falls off with ca. 3 dB per distance doubling. The B1 has a short critical distance (not directional, low room absorption) so the behavior becomes quickly a mix of reverberant field and direct sound which tends to also look fairly similar to a 3 dB per distance-doubling fall-off over a good stretch.		Taking all this together we see roughly the following picture: The {{L1}} has a fairly large critical distance, i.e. it’s mostly direct sound and that falls off with ca. 3 dB per distance doubling. The {{B1}} has a short critical distance (not directional, low room absorption) so the behavior becomes quickly a mix of reverberant field and direct sound which tends to also look fairly similar to a 3 dB per distance-doubling fall-off over a good stretch.

	To add insult to injury, this is all grossly simplified. In actual rooms, the reverberant field is never really constant, room modes get in the way, the L1 behaves not quite cylindrical in the lower mids, bass levels increase in the vicinity of wall, etc.		To add insult to injury, this is all grossly simplified. In actual rooms, the reverberant field is never really constant, room modes get in the way, the L1 behaves not quite cylindrical in the lower mids, bass levels increase in the vicinity of wall, etc.

	If it’s any consolation, we have actually measured the fall off versus distance for our combined system (L1 & B1) in a couple of different rooms and the ~~3dB~~ per distance- doubling describes the measured data remarkably well.		If it’s any consolation, we have actually measured the fall off versus distance for our combined system ({{L1}} & {{B1}}) in a couple of different rooms and the 3 dB per distance-doubling describes the measured data remarkably well.

	If anyone is still awake after this lengthy lecture (apologies), I’ll try to tackle the “philosophical” stuff next.		If anyone is still awake after this lengthy lecture (apologies), I’ll try to tackle the “philosophical” stuff next.