Dispersion in Bass Cabs. Is it really important?

[TrevorR]

I keep reading these threads about dispersion and I keep wondering about it. Now, the physics around dispersion from speakers is incontrovertible. Physics is physics. Fine, I get that. My degree is in a physical science. However, I do wonder whether the way in which this dispersion issue is discussed sometimes amounts to a bit of counting angels on the head of a pin. My rig clearly doesn't comply with what the physics says will give optimal dispersion. Two MarkBass Traveler cabs. A 1x15 on the bottom and a horizontal 2x10 on top. Pretty much the antithesis of the configurations discussed. Different cones arranged off axis from each other in a triangular shape. But I've never had enough of a problem to worry about. As a baclkine only situation or as a stage monitor through a meaty PA. Sure plenty of rooms have had funny acoustics when the only place for the bass amp to go is right in a corner or in front of a glass window or a heavy tapestry or a it's a strange shaped room with a double sided brick fireplace in the middle... or whatever. But through it all I've always managed to achieve a bass sound on "stage" and out in the crowd that was broadly acceptable. And certainly adequate for any punter to have had a perfectly enjoyable gig experience. And, having auditioned a range of makes and configurations I just really like the both the sound which that set up gives me and the flexibility and portability of the rig.

I do wonder in these discussions like there is a negation or an ignoring of The Pareto principle (I.e. the 80/20 rule) and that were treating acoustically very non-ideal (in its scientific meaning) environments as if they were ideal. The Pareto principle can be expressed as 20% of the effort required to a perfect result will get you to 80% of your objective. To achieve the remaining 20% will take 80% of the effort. It's a principle which is loosely mirrored ni a number of rules of thumb... exam technique - do all the easy bits of all the questions first (20% effort, 80% of the marks) don't try to get one question perfect before moving on to the next. The law of diminishing returns etc etc.

If any decent cab choice/configuration produces an 80% result which creates an environment which is acceptable to both you as a player and the audience as listener any effort to optimise beyond that point may start to take more effort/convenience than the solution creates.

Certainly when I look at some of the optimised systems that are posted here or elsewhere (e.g. two TC 2x10s stacked short end on short end - used as an example because of the rounded cab profiles) I know for certain that any enjoyment I might get from a more optimally dispersed sound bound be completely negated by a constant background worry that they might topple over at any minute. That stress would translate into my playing which would give a significantly reduced listening experience for my audience (even if they were listening to me with a lower risk that they might be standing in an diffusion or reflection peak or trough). For me that's an example of where "good enough" is what the words actually say... Good. Enough - that is perfectly adequate for the circumstances and completely fit for purpose. And we can leave struggling to achieve that last 20% to places like Abbey Road and RAK where it matters, rather than the Dog and Duck, or even Jagz, where it doesn't.

Anyway, that's my personal Minority Report. Please feel to ignore as necessary.

[Beer of the Bass]

[quote name='TrevorR' timestamp='1495141841' post='3301663']
If any decent cab choice/configuration produces an 80% result which creates an environment which is acceptable to both you as a player and the audience as listener any effort to optimise beyond that point may start to take more effort/convenience than the solution creates.

[/quote]

Interesting post. It's true that even with the best optimised rig the sound will be different as you move around the space in many rooms, and most of the time we're sufficiently used to that not to be bothered by it. The only times I've noticed dispersion from backline amps becoming a problem are either if I can't hear with enough clarity to properly follow what the musicians are doing (particularly when the amp serves as a monitor), or when the on-axis upper midrange peakiness is so pronounced as to be uncomfortable in one spot while it sounds fine everywhere else. So for me "good enough" is when neither of those happens, but then I gig in some fairly haphazard situations so perhaps my standards aren't all that high!

Edited May 18, 2017 by Beer of the Bass

[Guest bassman7755]

[quote name='TrevorR' timestamp='1495141841' post='3301663']
[color=#282828][font=helvetica, arial, sans-serif]Certainly when I look at some of the optimised systems that are posted here or elsewhere (e.g. two TC 2x10s stacked short end on short end - used as an example because of the rounded cab profiles) I know for certain that any enjoyment I might get from a more optimally dispersed sound bound be completely negated by a constant background worry that they might topple over at any minute. [/font][/color]
[/quote]

So what about when your playing in a band using PA cabs on stands you must spend all your time worrying if they are going to fall over.

[TrevorR]

[quote name='bassman7755' timestamp='1495150927' post='3301739']


So what about when your playing in a band using PA cabs on stands you must spend all your time worrying if they are going to fall over.
[/quote]

The thought had occurred as a wedding gig got noisy and rowdy now and then... But then the width of the base of the tripod vs the height of the cab seemed more inherently stable. I've certainly been bashed in the teeth by my mic on the odd occasion as une of the guests drunkenly bumbled into it during a particularly lively rendition of Mustang Sally.

My main point still stands though. In this discussion is this all trying to achieve perfection in a inherently non-perfect environment and where that level of near perfection isn't necessary to provide the service you are there to provide to a high standard of quality?

Edited May 19, 2017 by TrevorR

[Guest bassman7755]

[quote name='TrevorR' timestamp='1495171140' post='3301762']
My main point still stands though. In this discussion is this all trying to achieve perfection in a inherently non-perfect environment and where that level of near perfection isn't necessary to provide the service you are there to provide to a high standard of quality?
[/quote]

Well the speaker config with the best dispersion also happens to be the best on portability and stage footprint fronts too generally so its not like your missing out on something else or paying a premium for the privilege, your only objection is to be fair somewhat idiosyncratic.

[grandad]

As I practice and move around, seeking to position myself where the tone hits my preferred spot, I often ruminate about the dispersion of this or other amp/cabs I use/have used. Having read up on the subject I often find a conflict between the theory and my experience.

The easiest cab I have to position myself with is my Ampeg B115E. It sounds good almost anywhere from a couple of feet away in any setting, whereas the TCE 2 x 8" is devil to position myself with.

The conflict in my mind is between the larger speaker = narrower beam, smaller speaker = wider beam, which in my experience behave the opposite. Theory states that the larger the source compared to the wavelength the more narrow or directional the beam. What am I missing here?

[Guest bassman7755]

The 2x8 dispersion is going to be better than the 15 in one axis (perpendicular to speaker stacking) and worse in the other (inline with speaker stacking).

[grandad]

My thoughts have moved on to considering a piston in a box compressing and rarifying the air of a larger box in which it and your ears reside. The resulting sonic experience of course will not necessarily audibly illustrate the theory.

On reading over the above it sounds rather text-bookish but never-the-less true.

Edited May 22, 2017 by grandad

[Bill Fitzmaurice]

[quote name='grandad' timestamp='1495185446' post='3301907']
The conflict in my mind is between the larger speaker = narrower beam, smaller speaker = wider beam, which in my experience behave the opposite. Theory states that the larger the source compared to the wavelength the more narrow or directional the beam. What am I missing here?
[/quote]It's not theory, it's law. Use this to illustrate:
http://www.acoustics.salford.ac.uk/feschools/waves/flash/diffractionslider.swf
Dispersion is why tweeters are smaller than midranges, midranges smaller than woofers.
[quote]On reading over the above it sounds rather text-bookish[/quote]The behavior of sound waves isn't intuitive, because unlike light waves we can't see the result.

[FinnDave]

[quote name='Bill Fitzmaurice' timestamp='1495453828' post='3303793']
The behavior of sound waves isn't intuitive, because unlike light waves we can't see the result.
[/quote]

Unless you're Owsley, of course:
[quote][color=#000000][font=-webkit-standard][size=5][b]I think my knowledge of the true nature of sound dates back to the period of the L.A. Acid Tests and specifically, one of the rehearsals we had in the house in Watts when I actually saw sound coming out of the speakers. It was total synesthesia, and I've never experienced that at any other time. It was just a unique experience. And it so completely blew my mind, that I realized, "Hey, no matter what, I've got to remember what this (the sound) is doing. I went around and inspected it very carefully, and I spent a lot of time absorbing what it was doing and realizing how different it was from what I thought sound did. And that became the foundation for all the sound work that I've done. The fact that I was able to convert aural information into a three-dimensional image-- it was all coming from my ears, of course, but transforming it into a visual form.[/b][/size][/font][/color][/quote]

[hrnn1234]

I see I agree with many here. I can't remember the last time I played without a PA. Regardless of the size of the venue, the bass is run always through the DI (maybe it's because of a strict rock type of event background).

Also, having worked as a sound technician many years, it was always a blessing when I could convince the musicians to place their cabs 90 from the audience, only covering the stage. As stevie says, you can only hope someone did a proper design of the PA system- but it will get worst if the cabs are pointed at the audience and the sound guy can't arrange any volumes in real time (and even if, not affecting how the guys hear themselves on stage).

I know I'm an extremist in my views, but I don't see why must the backline fulfill any PA tasks when it can be avoided.

[FinnDave]

In the 120 plus gigs I've played with The Wirebirds, I doubt that more than 10% have had the bass through the PA. Apart from vocals, the only thing we mic up is usually the bass drum. Only when we play a festival or bike rally (and not always, even then) do we have the benefit of a big PA and sound crew.

[Chienmortbb]

[quote name='FinnDave' timestamp='1495459795' post='3303872']
In the 120 plus gigs I've played with The Wirebirds, I doubt that more than 10% have had the bass through the PA. Apart from vocals, the only thing we mic up is usually the bass drum. Only when we play a festival or bike rally (and not always, even then) do we have the benefit of a big PA and sound crew.
[/quote]+!

[GregBass]

[quote name='FinnDave' timestamp='1495459795' post='3303872']
In the 120 plus gigs I've played with The Wirebirds, I doubt that more than 10% have had the bass through the PA. Apart from vocals, the only thing we mic up is usually the bass drum. Only when we play a festival or bike rally (and not always, even then) do we have the benefit of a big PA and sound crew.
[/quote]

Yup - this is my experience as a regularly gigging bass player in a pub band. This weekend we are putting everything through a FOH PA for the second time in my three year stint with my current band. The rest of the time we put just vocals and bass drum through the PA.

Edited May 22, 2017 by GregBass

[hrnn1234]

well, I think it couldn't be clearer. dispersion is important only if the conditions of how you usually gig make it important.

[BigRedX]

I'm assuming that bassists who aren't being put through the PA are playing in bands that own their own system?

[Phil Starr]

[quote name='BigRedX' timestamp='1495531452' post='3304442']
I'm assuming that bassists who aren't being put through the PA are playing in bands that own their own system?
[/quote]

I don't think it's quite as simple as that. It's probably almost always true that people who use a professional sound engineer will be steered towards a proper front of house mix, with stage levels kept as low as possible and backline as monitors only.

For pub gigs (and the like) even with your own PA pragmatism rules. With no-one mixing out front many of the advantages of 'everything through the PA' will have gone. A full mix means miking up the drums, with a lot of extra complexity, and small venues don't demand high levels to fill the room so the onstage levels are bearable. With often one poor band member setting up the PA time to set up and knock down needs to be reduced, so even if the PA is up to it you won't necessarily put anything more than vocals through. Stage space and access for loading become issues too. Keeping it simple makes a sensible compromise

Personally I've a range of PA including a choice of multiple tops and subs available. I've used my biggest set up with up to 2,000 people so it's adequate for most things. I don't use the full set up down at the Dog and Duck and most of the times it's everything mixed to the drums (heavy sticks confiscated ) and just vocal PA through the smallest lightest tops. I could put bass through the tops and that'd be my first choice but the rest of the band (drummers especially) usually like a lot of bass so I end up with backline I could do way better mixing out front and cutting the backline out of the vocal mics but the places we play wouldn't stand the cost of a sound engineer and wouldn't thank you for setting up whist they are finishing serving food, we still get compliments on our sound from time to time.

Edited May 23, 2017 by Phil Starr

[Conan]

[quote name='BigRedX' timestamp='1495531452' post='3304442']
I'm assuming that bassists who aren't being put through the PA are playing in bands that own their own system?
[/quote]

That's certainly my experience. Then the odd gig at a festival or venue with it's own (larger) PA.

[lowhand_mike]

[quote name='Phil Starr' timestamp='1495534587' post='3304469']
we still get compliments on our sound from time to time.
[/quote]
exactly this, ive played through a cheapish 4x10 for years now, its usually just vocals and bass drum through the PA and ive never had a negative commment on my/our sound, and often had complements about my sound. that 80/20 rule sounds about right tbh, what i get out of my amp and cab is good enough for every situation ive played so far from small rooms to outside (on a trailer, on grass, on patio). that final 20% is just not necessary and punteers just arent going to notice in a pub/small gig and i'll leave it up to people like barefaced to try and get there not that i'll ever need or afford to buy into it.
I'm considering a 2x10 to go with my 4x10 but tbh its more about satisfying myego than anything else and even then it would be basic.

[BigRedX]

[quote name='Phil Starr' timestamp='1495534587' post='3304469']
I don't think it's quite as simple as that. It's probably almost always true that people who use a professional sound engineer will be steered towards a proper front of house mix, with stage levels kept as low as possible and backline as monitors only.

For pub gigs (and the like) even with your own PA pragmatism rules. With no-one mixing out front many of the advantages of 'everything through the PA' will have gone. A full mix means miking up the drums, with a lot of extra complexity, and small venues don't demand high levels to fill the room so the onstage levels are bearable. With often one poor band member setting up the PA time to set up and knock down needs to be reduced, so even if the PA is up to it you won't necessarily put anything more than vocals through. Stage space and access for loading become issues too. Keeping it simple makes a sensible compromise

Personally I've a range of PA including a choice of multiple tops and subs available. I've used my biggest set up with up to 2,000 people so it's adequate for most things. I don't use the full set up down at the Dog and Duck and most of the times it's everything mixed to the drums (heavy sticks confiscated ) and just vocal PA through the smallest lightest tops. I could put bass through the tops and that'd be my first choice but the rest of the band (drummers especially) usually like a lot of bass so I end up with backline I could do way better mixing out front and cutting the backline out of the vocal mics but the places we play wouldn't stand the cost of a sound engineer and wouldn't thank you for setting up whist they are finishing serving food, we still get compliments on our sound from time to time.
[/quote]

My own experience of playing in originals bands over the last 8 years is that in almost every case* there is an in-house PA system with an engineer. The majority of these venues are no different in size to the average covers band pub gig but the PA supplied will always be adequate enough for the kick and snare drum (at a minimum) too be mic'd up and the bass to be DI'd.

As I've said previously, several of the most recent gigs I have played, I have been asked to turn down my rig to such an extent, that I have relied on the wedge monitors in order for me (and the rest of the band) to be able to hear any bass guitar. In these instances the dispersion characteristics of the bass cabs have become completely irrelevant.

*In fact the only time I can recall there being no PA with the venue, was one where between the gig being booked and actually occurring the pub in question had undergone a refurbishment that had included removing the in-house PA system and not replacing it.

Edited May 23, 2017 by BigRedX

[Conan]

[quote name='BigRedX' timestamp='1495538226' post='3304517']
My own experience of playing in originals bands over the last 8 years is that in almost every case* there is an in-house PA system with an engineer. The majority of these venues are no different in size to the average covers band pub gig but the PA supplied will always be adequate enough for the kick and snare drum (at a minimum) too be mic'd up and the bass to be DI'd.

As I've said previously, several of the most recent gigs I have played, I have been asked to turn down my rig to such an extent, that I have relied on the wedge monitors in order for me (and the rest of the band) to be able to hear any bass guitar. In these instances the dispersion characteristics of the bass cabs have become completely irrelevant.
[/quote]

Clearly this is going to vary from region to region, and the type of gigs and venues involved. But there are lots of bands and bass players who would love your situation to apply to them too! That said, just because there is a house PA and soundman doesn't mean they will get a good sound...

For those of us who play solely on backline, the dispersion of our bass cab(s) remains an important consideration.

[BigRedX]

[quote name='Conan' timestamp='1495538590' post='3304521']
Clearly this is going to vary from region to region, and the type of gigs and venues involved. But there are lots of bands and bass players who would love your situation to apply to them too! That said, just because there is a house PA and soundman doesn't mean they will get a good sound...

For those of us who play solely on backline, the dispersion of our bass cab(s) remains an important consideration.
[/quote]

The Terrortones played all over the country, and with that one exception (and the house party mentioned earlier in this thread) in every case a PA and engineer were supplied at the gig.

I see that as another reason not to go back to playing covers. I like the idea of, if necessary, being able to rock up at a venue 15-20 minutes before the band is due to be playing, and not have to be there from the early evening onwards spending ages pissing about setting up and later breaking down the PA and lights (which was my experience of playing in a covers band).

[Beer of the Bass]

There are a few places in my town that are bars putting on live music, rather than dedicated music venues. They'll put on a mixture of covers or originals of a fairly mainstream nature. If they have their own PA, it'll usually be a little mixer and a couple of powered tops that live in a store room between gigs, or sometimes a knackered old mixer amp and passive speakers, rarely any monitors. I don't do many of those gigs, but when I do, the bass won't be through the PA.

[cheddatom]

I play in an originals band that still manages to get the odd pub gig where we take our own PA. For these, the bass never goes in the PA, but neither do any drums

[Bill Fitzmaurice]

[quote name='cheddatom' timestamp='1495544467' post='3304606']
I play in an originals band that still manages to get the odd pub gig where we take our own PA. For these, the bass never goes in the PA, but neither do any drums
[/quote]It's actually important to put drums in the PA, the snare in particular. Even a ham fisted troglodyte's snare doesn't carry all that well throughout most rooms. Having the bass in there as well doesn't hurt, but not for the lows that carry well, for the mids and highs that don't. Just be sure to high pass the channel at 100Hz and/or roll off the bass EQ so it doesn't stress the PA. The same applies to guitar, for the same reason. It's not about volume, it's about dispersion.