Dark Side of the Moon Bass issues

[JonFo]

I still believe many of you are still experiencing a combination of:

• Mid-Bass issues
• Room modes
• Possibly issues with gear ? (worth looking into).

So I decided to capture some RTA measurements of the passages in question. Screen shots of these follow.
The RTA is of the sum of the three front channels + sub, so ALL relevant audio is accounted for.

But looking at the songs play, DSoTM is not that great at infrasonics. It’s mostly above 35hz, with tons of the energy in the 60 to 180hz range.

I’ll post some RTA’s of real bass later

So here is the RTA of Money at 2:29
Look at the peak hold bars as well (the white horizontal lines in each column) to see the peak in the previous 0.02s.

 

[JonFo]

Here is the 2:35 measurement on Money:

 

[JonFo]

And this is the intro to Breathe, at the point (0:10) where one would think the bass is loudest, but as we see, it’s mostly 50 to 200Hz energy.

If you have untreated room modes, or your speakers have resonances in that range, it could be ‘muddy’, but it’s not really stressing the sub frequencies too much.

 

[JonFo]

And here is the heartbeat from DSoTM. Again, look at the peak hold bars for where the energy really is.

You can see it’s in the 40 to 50hz range. Not a big workout for a decent sub.

 

[JonFo]

Now, for some real bass. The following several measurements are taken from the Dr. Chesky’s 5.1 surround extravaganza DVD-Audio disc (in 24/96).

This is track 1 – Lift off of Discovery

Note the totally saturated low frequencies. The room really shakes with this, but no boom thanks to great treatments and Audyssey corrections.

 

[JonFo]

Another crowd pleaser, track 26 – Organ and chimes.

There are some low pedal notes in here, this shot is not the deepest, but you can see the breadth of frequencies that are engaged at high levels.

IB subs handle this kind of stuff very well.

 

[JonFo]

The DSoTM heartbeat is nice, but sounds like amateur hour next to the heartbeats on the Dr. Chesky record.

Here is a 50 Hz heartbeat. One hears this quite well, and the room is shaking a bit.

 

[JonFo]

And lastly, the 20Hz heartbeat. The air pressure changes with this one (if your sub is up to it).

A good sub will just produce air movement, no buzzes or rattles on these.

Trust me, the only way these will sound good is in a well treated room with massive subwoofage.

 

[Dreamer]

JonFo, that is EXCELLENT research, and it's very helpful to understand what's going on with tiny little samples of time in these tracks, but what they DON'T take into consideration is the 4th dimension--time.

I'm going to fall back on my knowledge and expertise in another obscure subsection of psycho-acoustics--their application to what are called "light and sound machines" and the creation of what are called "beat frequencies" to try and further explain my theory.

When two frequencies of VERY similar range are played very closely to each other, they can create what is called a "beat frequency", which is equal to the difference of the two original frequencies. For instance, if a 50Hz frequency is played over or soon before or after a 40 Hz frequency, (in a room, or even through headphones--the "beat frequency" can be created by your brain's processing of such tones through headphones, which is how it works in "light and sound machines"), their interaction creates a 10Hz tone. This tone is FAR below the hearing abilities of humans, but it IS perceivable, and in L&S applications, these "beat frequencies" are utilized for brain-wave entrainment--your brainwave patterns actually align with the beat frequency. Beat Frequencies can also be created in the "sonic" range, anywhere up and down the audio spectrum, if the right frequencies are interacting at similar decibel levels.

So in a recording, if (as your charts show) there are heavy tones in the 60Hz range, and heavy tones in the 45 Hz range, there MIGHT be a beat frequency created at 15Hz, which may be further reinforced by the acoustics of some rooms. Since your charts only go down to 20Hz, they are not showing these subsonic frequencies...

Beat Frequencies are not only VERY strong harmonic anomalies, but they also tend to be perceived as "pulsing" or "rumbling" sounds or sensations, because of the nature of their waveform. Perhaps, THIS is what's happening, since I think it's safe to assume that most of these LPs and early-release CDs probably don't have ANY information below 20Hz due to the production practices back then, based on the assumed limitations of human hearing and stereo reproduction equipment.

I think your charts show a LOT, but I think they might be more like a map pointing in the right direction rather than a definitive representation of what might actually be going on sonically with these recordings in certain rooms.

Again, I get back to Nick Masons kick drum lines on these tracks. Bass kick drums are DEFINITELY in that 40-60Hz range, depending on how they are tuned, how hard they are struck, and how far the pedal mallet travels before striking the head. If two kicks are closely spaced, and repeated over and over again, it is a VERY safe assumption that there may be beat frequencies created rom their varying frequencies. The first strike of a beat might be right at 50Hz, but if the second strike comes quick enough, the drum head hasn't had a chance to completely recover to a relaxed state, and will be tighter when the mallet hits the second time, so that the second strike may create a 55Hz tone, which MAY create a beat frequency, ESPECIALLY if this pattern is repeated over and over in quick succession. And if you listen, it's easy to hear Mason's "Energizer Bunny on Crack" bass beat. Like I said before, the kick drum isn't so much beating out time--it's more like he's trying to create a bass-drum sonic version of "continuous breathing" like is used with a didgeridoo. I'm suggesting that those rapidly-spaced bass beats are actually creating an additional tone in the room that is not on the recording at all, but is, in fact, a "beat frequency".

Charts and graphs show a LOT, but we need to remember that most of them are representations of a VERY brief time-slice. We can't forget the 4th dimension in acoustical analysis--sound takes time to travel in a room, and a LOT can happen in those split seconds, with soundfields as frequency-rich as a Pink Floyd album...

Just my opinon though...

--Richard

 

[User211]

JonFo, that is EXCELLENT research, and it's very helpful to understand what's going on with tiny little samples of time in these tracks, but what they DON'T take into consideration is the 4th dimension--time.

Exactly the point I was going to make - though we do have peak readings which presumably get reset at whatever frequency Jon has requested from the s/w, I suspect, if not using the default.

Jon has gone to some effort here, and I find that quite touching. Good stuff - someone is trying to research it with a scientific approach. Whilst I don't need to do that because I know full well what I can hear and see what my Descent is doing, I reckon I could get a plot using a high quality condensor mike of a place where there is very little music, but significant low bass output. The point I am thinking of requires a cheat to hear it (turning the Descent output up) but it sure as hell WILL be measurable without being confused with a load of music output.

I can't do this anythime soon, but if I get the chance this weekend (no promises) I'll do it. Might depend on the soundcard in my laptop - not sure how good it is, to be honest. Might have to use my Edirol if it will pick it up because it's quiet and my laptop fan makes way too much noise - really much more than it should - the poor old girl is getting a bit long in the tooth. But the noise it makes is way higher than what is in question here.

BTW: my Descent settings are 25Hz switched in, level 3 on the output (quite low) by default normally and for the most part while I was listening to said disc.

 

[JonFo]

JonFo, that is EXCELLENT research, and it's very helpful to understand what's going on with tiny little samples of time in these tracks, but what they DON'T take into consideration is the 4th dimension--time.

Dreamer, you are right, time is a very critical component of low-frequency phenomena.

That’s why I use waterfall plots to tune the low-frequency resonance in the room, and why an FIR convolved room corrector like Audyssey can correct these low frequency issues.

…
I'm going to fall back on my knowledge and expertise in another obscure subsection of psycho-acoustics--their application to what are called "light and sound machines" and the creation of what are called "beat frequencies" to try and further explain my theory.

When two frequencies of VERY similar range are played very closely to each other, they can create what is called a "beat frequency", which is equal to the difference of the two original frequencies. For instance, if a 50Hz frequency is played over or soon before or after a 40 Hz frequency, (in a room, or even through headphones--the "beat frequency" can be created by your brain's processing of such tones through headphones, which is how it works in "light and sound machines"), their interaction creates a 10Hz tone. This tone is FAR below the hearing abilities of humans, but it IS perceivable, and in L&S applications, these "beat frequencies" are utilized for brain-wave entrainment--your brainwave patterns actually align with the beat frequency. Beat Frequencies can also be created in the "sonic" range, anywhere up and down the audio spectrum, if the right frequencies are interacting at similar decibel levels.

So in a recording, if (as your charts show) there are heavy tones in the 60Hz range, and heavy tones in the 45 Hz range, there MIGHT be a beat frequency created at 15Hz, which may be further reinforced by the acoustics of some rooms. Since your charts only go down to 20Hz, they are not showing these subsonic frequencies...

Beat Frequencies are not only VERY strong harmonic anomalies, but they also tend to be perceived as "pulsing" or "rumbling" sounds or sensations, because of the nature of their waveform. Perhaps, THIS is what's happening, since I think it's safe to assume that most of these LPs and early-release CDs probably don't have ANY information below 20Hz due to the production practices back then, based on the assumed limitations of human hearing and stereo reproduction equipment.

I agree, beat frequencies could very well be at the root of the ‘rumblings’ others are reporting in this recording.
These resonances are often room induced and very visible in waterfall plots. Which is why treating the room is job one in my book.
I also believe it could well be an artifact created by harmonic distortion in the speakers if over-driven.

I think your charts show a LOT, but I think they might be more like a map pointing in the right direction rather than a definitive representation of what might actually be going on sonically with these recordings in certain rooms.

Again, I get back to Nick Masons kick drum lines on these tracks. Bass kick drums are DEFINITELY in that 40-60Hz range, depending on how they are tuned, how hard they are struck, and how far the pedal mallet travels before striking the head. If two kicks are closely spaced, and repeated over and over again, it is a VERY safe assumption that there may be beat frequencies created rom their varying frequencies. The first strike of a beat might be right at 50Hz, but if the second strike comes quick enough, the drum head hasn't had a chance to completely recover to a relaxed state, and will be tighter when the mallet hits the second time, so that the second strike may create a 55Hz tone, which MAY create a beat frequency, ESPECIALLY if this pattern is repeated over and over in quick succession. And if you listen, it's easy to hear Mason's "Energizer Bunny on Crack" bass beat. Like I said before, the kick drum isn't so much beating out time--it's more like he's trying to create a bass-drum sonic version of "continuous breathing" like is used with a didgeridoo. I'm suggesting that those rapidly-spaced bass beats are actually creating an additional tone in the room that is not on the recording at all, but is, in fact, a "beat frequency".

Charts and graphs show a LOT, but we need to remember that most of them are representations of a VERY brief time-slice. We can't forget the 4th dimension in acoustical analysis--sound takes time to travel in a room, and a LOT can happen in those split seconds, with soundfields as frequency-rich as a Pink Floyd album...

Just my opinon though...

--Richard

Just wanted to show what the content of the recording had vs the actual in-room.

I found it interesting that the DSoTM disc was not really that heavy on very low frequencies, but was quite rich in 40 to 160hz.

I highly recommend people who really want to know what’s going on in their rooms and system get REW and run some waterfall plots of low-frequencies. It’s an eye opener just how bad the time-domain performance of the avg. room can be.
Even custom designed rooms (like mine) have serious issues that still require a multi-pronged approach to address.

But to the point of the discussion, I still don’t believe the DSoTM recording has a problem, as it sounds just fine here. And I’ve heard this album many times over the years and on many different systems, and the current rig (from the multichannel SACD source) produces the best reproduction I’ve ever heard.

 

[SteveInNC]

Reference: SACD version: DSOTM which I grew up with in my party days, IMO (and some may vehemently disagree) ruins the music experience in MCH - it is gimmicky, sound all around you bouncing here and there, etc. It takes away or detracts from the music experience, again IMO.

MCH is certainly a matter of taste, and I tend to come down in the 2CH camp, just because that's how I've generally been exposed to particular tunes that I like, so that's what my brain expects.

I'll point out that when I saw Pink Floyd live in a stadium, they did the bouncing around the room effects at the actual concert, i.e. - they ran the show as multi-channel sound. "Money" in particular was bounced all around the stadium during the "cash register" effects.

 

[User211]

But to the point of the discussion, I still don’t believe the DSoTM recording has a problem, as it sounds just fine here. And I’ve heard this album many times over the years and on many different systems, and the current rig (from the multichannel SACD source) produces the best reproduction I’ve ever heard.

Even after the link I supplied where the recording engineer states that Breathe had/has LF issues? And the testaments from others?

 

[User211]

Jon - are you listening to the multi-channel version of the SACD only? Can you listen to the two channel one? The implication from what the recording engineer said is that he removed the troublesome noise from the mix on that version (it's ambiguous and unclear from what he says, though), at least for Breathe. But he may be being coy, and cleaned up the rest too on that version.

It's definately 100% on the 2 CH version of the Capitol SACD 2003. Clear as a whistle on my system. If you can force that, try it. My player won't play the surround mix.

Now if you come back and say you can't hear it on that, well... those room treatments must be too good!

 

[User211]

OK - obviously what is needed here is some FFT (fast Fourier transform) analysis - or more specifically TFFT - temporal FFT. What this does is splits up the the frequency components so we can see what is happening over time.

Sounds good in theory - but then everything works in theory. What I did was load my recording of the Martin Logan CLX playing ZZ Top's La Grange. 2 seconds of it is shown below. You can't see the axis labelling, but let me explain - the x-axis shows 2 seconds worth of the track. The y-axis is from 0Hz to 4000Hz - in other words it's a "zoom in" on the lower part.

The brighter (whiter) the image, the more energy is present. Obviously, the low frequency stuff we would be interested in to prove the Pink Floyd case is right down in the lowest few pixels. And there's lots of energy there. Why? The CLX doesn't go that low. Is it room excitation? Who knows. Anyway, the point is, I am not going to be able to prove the DSOTM case with this sort of result. And this quick activity saved me the time of going to the trouble of recording it.

I wonder what is going on here, to be honest. I used some free s/w called WavePad - not sure the programmer's maths is up to scratch, but he probably called some API of unknown origin to do it. This program won't allow any further zooming in.

Anyway, here is the graph:

 

[MiTT]

Looks like the Shroud of Turin to me!

Is Roger Waters secretly a Jesus Freak?

 

[User211]

Hey maybe I loaded "Jesus built my hotrod" by mistake!

 

[DrJRapp]

I've drawn the conclusion that you guys all have way too much time on your hands...LOL

Suggestion of what to do with that time....LISTEN TO MUSIC

What a concept!!!!!!!!

 

[FISH_MAN]

I've drawn the conclusion that you guys all have way too much time on your hands...LOL

Suggestion of what to do with that time....LISTEN TO MUSIC

What a concept!!!!!!!!

It sounds like the DR. has they cure! just don't use this time to listen to Pink Floyd's darkside of the moon :banghead: this has become one of my least favorite albums as time goes by and you guys are a lot older than me how do you still listen to this tired album?

 

[FISH_MAN]

I would not be surprised if the darkside is not riddled full of sonic gremlins I really do not think it is the sonic masterpiece it is haled to be