Can someone please explain why 'the bass' sounds better further away

[iconic]

I'm not stupid, many may argue that statement but I've got letters behind my name should I choose to use them (I think and they don't all end in T?) I'm a member of the Institute of Mechanical Engineers don't ya know.....which means I can go and sit in the library at Birdcage Walk should I take the fancy but....

.....near field, far field, 'inside the wavelength'....it's all very conflicting, the fact remains it [u][i][b]does[/b][/i][/u] sound better a few feet away than in front of the speaker.....but can anyone explain the reasoning, in simple speak to a dumbass like myself.....acoustics wasn't on the sylabus at college for a mech' eng'.

thanks in advance.

[Acebassmusic]

[quote name='iconic' timestamp='1371223439' post='2111425']
I'm a member of the Institut[b]ion[/b] of Mechanical Engineers don't ya know.....[/quote]

Sorry.....the detail orientated pedant in me broke loose Good trait for an engineer I hear. Anyway....back on topic....I'm another IMechE engineer who missed that lecture and would be interested in understanding why.

[JTUK]

Depends how much further you mean... I think it is all about accepting the compromise of what sounds good close up... and how far the sound travels keeping that sort of focus..!!
I used to deliberately sound cleaner..and possibly harsher when standing right on top of my cab...when I knew the sound would 'bloom' further away.
My aim is for my sound close up to be decently replicated at the back of a pub... but I also need to other guys in the band to altow that to happen by using dynamics and compatible core sounds that don't flood/swamp my own.

At a point where the bass sounds too big and therefore blurred, that is the point at which you have lost the sound, IMO.
How stressed we get at this or need to be, I tend to care less

[bassace]

And I'm a Chartered Civil Engineer - or rather I was until I stopped paying my subs to support their palatial HQ in Westminster. The reason bass sounds better far away is the same reason as bagpipes. Simple.

[Jonnyboy Rotten]

I work with acoustics a little and I believe it is the same reason as you should always leave at least 1 metre between a SPL (Sound Pressure Level) Meter and a noise source to get an accurate dB(A) reading.

It is to do with the time/distance it takes to let the sound waves 'settle' into a regular form. Closer than a metre and the dB(A) gets artificially inflated because of the 'excitement' of the sound wave close to the source.

If you listen close to the speaker (which is probably bad for your ears anyway! ) then some of the noise you hear will be this excited and unsettled waves which likely don't sound as great as the soundwaves that have settled down a bit further away.

[LukeFRC]

my playing sounds better once you get far enough away you can't hear it.

[ead]

[quote name='Jonnyboy Rotten' timestamp='1371229274' post='2111519']
It is to do with the time/distance it takes to let the sound waves 'settle' into a regular form. Closer than a metre and the dB(A) gets artificially inflated because of the 'excitement' of the sound wave close to the source.
[/quote]

I thought that in nature entropy (disorder) always increases in a system.

[jakenewmanbass]

Could it be to do with the length of the wave?

[thisnameistaken]

Bass speakers are much bigger than they look, and they aren't as loud if you stand inside the invisible bit.

[Lozz196]

I wish I knew why. It`s very irritating to get a great on-stage sound and find it sounds a slushy/boomy mess out front, so then, once you`ve got a great sound out front, it sounds like nasally/scratchy plucked elastic bands.

And they reckon we`re the simple guys in the band - how can we be with such a complex sound?

[BassTractor]

Don't know the answer, but I'd guess it's a simple case of phase differences. When you are at a distance, all sound comes from virtually the same angle.

best,
bert

[Myke]

I don't know... but thinking about that why do you close mic the amp in the studio? Apart from getting a larger input into the desk.

[miles'tone]

It's because all the bright, trebley frequencies get absorbed into walls and people whereas the bass keeps on travelling "through" everything.
Therefore, the further back you are, the more bass heavy the mix is.

Or something.

[Dingus]

It's because of what is known as the dispersal pattern . Generally speaking , the bigger the speakers you use in your cabs , the further away you need to be to hear the full impact of the sound . If you have cabinets with 18 inch speakers , they won't sound that loud or that good up close , but at the back of the hall they may well sound fine and be shaking the windows . One of the reasons the Ampeg SVT rig was so revolutionary when it came out in 1969 was that the speaker cabinet used multiple (eight ) smaller ( ten inch ) speakers to achieve high volume levels , and each set of two speakers was isolated by a baffle inside the cab , in effect to create four 2x10 cabinets . By doing so , the Ampeg cab had a completely different dispersal pattern and as a result gave an amazingly loud and clear and defined sound on stage that was revolutionary in its day and which still sounds fantastic now . So how far away you have to be to hear the best bass sound depends to a certain extent on what gear you are using , but the laws of physics come into the equation , and low frequency sound has it's own peculiarities that only someone much more scientific than me ( grade 3 CSE in Physics ) would be able to explain .

Edited June 14, 2013 by Dingus

[TimR]

It doesn't.

Usually it's because the speakers are pointing at your knees. Think of the speaker as a torch shining sound out. The further away you are the more likely it is that your ears will be in the "beam".

The sound wave is a compression wave, the air sucks and blows, it's not a longitudinal standing wave like you get in a string going up and down. Unless you get the wave bouncing back off a wall. Then you get all sorts of other issues.

Edited June 14, 2013 by TimR

[TimR]

[quote name='Dingus' timestamp='1371236071' post='2111669']
...
and low frequency sound has it's own peculiarities that only someone much more scientific than me ( grade 3 CSE in Physics ) would be able to explain .
[/quote]

High frequencies are more directional and low frequencies are less directional.
High frequencies will bounce off small hard objects, low frequencies will just go round them.

[discreet]

When you stand next to your rig you hear direct sound. Further away that gets mixed in with sound that is reflected off the walls, floor and ceiling and so forth so it sounds different. That's why when using 'near field monitors' for mixing you need to, er... be near them so the sound isn't compromised by reflections from the room. It's a boundary effect.

Whether or not this reflected bass sound is 'better' or not depends on other variables... and is a matter of opinion.

Edited June 14, 2013 by discreet

[iconic]

Ok, this is good cheers guys
.....the bit about this "no it doesnt its because the speaker is by my knees" bit is a tad confusing and yes ive seen close mic'd speakers for recording but

...if i kneel down close to the speaker and inch backwards down my room i do hear a difference and then seem to hit a sweetspot that doesnt seem to change the further back i go within reason, my cables 15m

..... hope the neighbours arent watching this!?!

this is with my 1x15".....i'll try it with my 2x10" tomorrow and see if distance changes?

[TimR]

[quote name='iconic' timestamp='1371238609' post='2111718']
Ok, this is good cheers guys
.....the bit about this "no it doesnt its because the speaker is by my knees" bit is a tad confusing and yes ive seen close mic'd speakers for recording but

...if i kneel down close to the speaker and inch backwards down my room i do hear a difference and then seem to hit a sweetspot that doesnt seem to change the further back i go within reason, my cables 15m

..... hope the neighbours arent watching this!?!

this is with my 1x15".....i'll try it with my 2x10" tomorrow and see if distance changes?
[/quote]

You're in a small square room. The air bounces of the far wall and 'crashes' into the air coming directly from the speaker. This will create what's known as a standing wave. Different points along that wave will have different sweet spots depending on the frequency and where you stand.

Big venues and outside this will be a non issue.

Try tilting your cab back slightly and angle it slightly so it doesn't project at 90 degrees to a wall. Ideally your cab should have its back close to a wall. This will stop reflections from the back wall interfering with the direct sound from the cab. (covered in a later post no doubt).

[Guest bassman7755]

Its an innate property of ported cabs. Because of the way porting works you hear more low frequency volume if your ear is mororless the same distance away from the port and the speaker and for that you usually have to be some distance away from the cab.

[grandad]

Interesting question Iconic. Acoustics is fascinating but the more I read the more I realise there is to know.

I think one of the main points to remember is that as you move away from the sound source the proportion of direct and reflected sound differs thus each position will sound different.
The distance from the sound source and the path length of the reflected sound will vary from place to place. Hence the relative phases will differ from place to place.
Sometimes direct & reflected waves will be in phase and add together thereby increasing the loudness of that particular frequency. Sometimes they will be out of phase and subtract and thereby reduce it.

I used to get my students to walk the length of 2 cycles of a 40 Hz standing wave in a narrow long corridor. They were always amazed at this experience and started to understand the nature of sound from then on.

I expect a speaker is just a piston to you and a simple linear motor to me. But when you start to look into how they do their job don't they just get frightenly complicated?

Edited June 15, 2013 by grandad

[Junkyard Rocket]

It is because guitarists tend to stand at the front at the stage, but bass players tend to prefer to hang around towards the back.

http://www.youtube.com/watch?v=vh5kZ4uIUC0

[gjones]

[quote name='iconic' timestamp='1371223439' post='2111425']
I'm not stupid, many may argue that statement but I've got letters behind my name should I choose to use them (I think and they don't all end in T?) I'm a member of the Institute of Mechanical Engineers don't ya know.....which means I can go and sit in the library at Birdcage Walk should I take the fancy but....

.....near field, far field, 'inside the wavelength'....it's all very conflicting, the fact remains it [u][i][b]does[/b][/i][/u] sound better a few feet away than in front of the speaker.....but can anyone explain the reasoning, in simple speak to a dumbass like myself.....acoustics wasn't on the sylabus at college for a mech' eng'.

thanks in advance.
[/quote]

[color=#282828][font=helvetica, arial, sans-serif]I was told by a sound engineer that because bass frequency sound waves are so long (measured in metres rather than centimetres), that they have to be further away from the speaker before they form fully and you can hear them correctly.[/font][/color]

[color=#282828][font=helvetica, arial, sans-serif]Nice webpage with diagrams so you can envision the sonic waves doing their thing,[/font][/color]

[url="http://hyperphysics.phy-astr.gsu.edu/hbase/sound/diffrac.html"]http://hyperphysics....nd/diffrac.html[/url]

[Ziphoblat]

I'm going to do a bit of maths, which will probably be flawed.

I'm going to use the frequency 37Hz just because that happens to be the lowest part of the frequency response of the cabinet I use (BF S12T).

37Hz is, as we know, 37 cycles per second. Which means it takes 0.0270270 (etc) seconds (1/37) for one cycle at that frequency.

The speed of sound is roughly 340m/s depending on temperature/altitude variables etc. 340 x 0.0270270 (etc) equals 9.19.

So if I've done this correctly, a full cycle of the lowest frequency that my cabinet kicks out takes 9.2 meters to occur. I suppose if I've done that correctly it explains why distance makes low frequencies sound better.

[TimR]

[quote name='Ziphoblat' timestamp='1371335637' post='2112794']
I'm going to do a bit of maths, which will probably be flawed.

I'm going to use the frequency 37Hz just because that happens to be the lowest part of the frequency response of the cabinet I use (BF S12T).

37Hz is, as we know, 37 cycles per second. Which means it takes 0.0270270 (etc) seconds (1/37) for one cycle at that frequency.

The speed of sound is roughly 340m/s depending on temperature/altitude variables etc. 340 x 0.0270270 (etc) equals 9.19.

So if I've done this correctly, a full cycle of the lowest frequency that my cabinet kicks out takes 9.2 meters to occur. I suppose if I've done that correctly it explains why distance makes low frequencies sound better.
[/quote]

But what does that have to do with anything. That's only relevant in a standing wave and just means that there will be nodes when the room is a multiple of whole, half, quater, etcl number of wavelengths long.

It has much more to do with room size and where you're standing than just being further away from your cab.