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Non ADA Gear => Speakers & Cabinets => Topic started by: rabidgerry on November 29, 2014, 02:48:17 PM

Title: Too much resonant bass????
Post by: rabidgerry on November 29, 2014, 02:48:17 PM
Has anyone ever had an issue with tooooooooooooo much rumbley bass coming from their cabs?

I recently have moved all the gear round in my practice room and we put the drums in the corner and the guitars at on wall and the bass in the middle of the room.

The bass rumble I got of my cabs however was EXTREME.  So I moved my stuff today away from the wall and it helped a little bit.  I also used milk crates to keep my cabs up off the ground to help with the situation.

The outcome was better but still I had to drop the global bass of my effects unit like -9db because of rumble.  I could have reduced it further but I screwed everything too much if I dropped it, so I settled for somewhere in between rumble and no rumble.

Anyways, I have a theory, I play through 4 2x12" cabs. 

(I chose the cabs specifically for my amps because of their impedance settings and also 2 x 12" cabs being brought to a gig can fit in a small car as you can put one in the boot and one in the back seat.)

The theory is, perhaps I am getting more rumbley bass because the way I have the cabs stacked??  I stack 2 on top of one another SEE ATTACHED PIC.  The cabs have small rubber feet.  They are also side by side.  Am I possibley getting weird coupling effect with each cab coupling to each other from being on top and possibly at the side of one another SEE ATTACHED?

let me know what you think guys.

Just so you know I can hear the tight bass I need in my distorted guitar to have a nice tight thump bottom end, but I just have all this excess crazy bowel shaking boomeyness going on if I move anywhere other than the centre of speaker cabs.  It seem worse if I stand to the sides.

All information or suggestions welcome folks.
Title: Re: Too much resonant bass????
Post by: rnolan on November 29, 2014, 10:47:03 PM
This where the room eq knob on the MP2 is very useful, intended to adjust between very bright (shiny wood, glass) and dead carpeted rooms. Works quite well so similar eq is an option.
The cabs will definitely couple the way they're stacked, particularly bottom end. A bit more space between the 2 stacks will help a bit.  Up off the floor is the go, but you've done that.
My other thought is standing waves which are always prevalent when you have parallel surfaces (e.g. walls/ceilings/floors) and why studio control rooms have angled walls and glass (and big active bass traps, generally along the back wall). A good way to visualise what standing waves do is from the beach when a wave going back out to sea collides with a wave coming in, makes a big splash typically up and down (you get to see the up), thus standing wave. The longer lower wavelengths (bass) are more prone (so bottom end rumble/mud) as those frequencies double in power from the collision. So not aiming your cabs at the opposite wall will help as will hanging thick carpet/drapes 3 to 4 inches in front of the wall, they need to be able to move so hang them, some of the bottom end will be absorbed (turned into motion of carpet/drape). This is a crude active trap. You can do more targeted sophisticated bass traps, simple design is long rectangular box with absorbing bats/rock wool whatever, hanging down vertically from the top inside the box and the box entry point (e.g. 12" square hole at front of one end of the box) for the bass to go in, bats turn it into motion so trapped.  The size of the entry is tuned to various frequencies by its size (though not so critical with porous trap). Look up active traps (http://en.wikipedia.org/wiki/Bass_trap), what I've described is a porous bass trap.
Title: Re: Too much resonant bass????
Post by: rabidgerry on November 30, 2014, 05:45:58 AM
Thanks for that man, what an answer.  I'd be lying if I understood it all though  ;)

Anyways, I thought I'd point out that the 2 x 12" have rubber feet, but I still think they may be coupling with one another.

Also, the photo I attached, shows how the cabs are stacked but it doesn't show the room positioning since I have changed this over the last few weeks.  The cabs are now facing the drums in the corner of the room.  Each stack rests on 2 milk crates.  I also moved them slightly wider this week.  However I am tempted to widen them a little more. I'm just stating this in case it changes the game slightly.  I also have a rack EQ which is a phonic peq 3600 which I haven't used in a while.

(note, I usually use ART DXR delay unit and have a very short delay that I run one side only through (right), this is to achieve Haas effect.  I don't need to if using stereo effects but it means drier patches I use will still be in stereo.  It is currently in repair)

So you think I should create some bass traps?  There is a lot of stuff in my practice room, the sound does not just hit bare walls.  One more thing to note.  The bassist cabs are on the floor, no feet, no nothing, I know his stack is coupling for sure which probably makes the problem worse right?  We are looking for something to place his gear on as well but there seems to be no milk men around to steal milk crates from these days :D
Title: Re: Too much resonant bass????
Post by: rnolan on December 01, 2014, 04:52:07 AM
Hey RG, (Anyways, I thought I'd point out that the 2 x 12" have rubber feet, but I still think they may be coupling with one another.)
That's not enough, though helps a bit. But we start down a slippery slope with that conversation. The "acoustic" coupling between the boxes etc particularly bottom end. It's fine they couple down each channel, just get them spread and careful where you point them. Ok pointing them into a corner (known bass boom bad guy spot). If you do the drape/carpet/rug thing all round the walls it will help (even better to have 2 layers (e.g. in drum corner) 100mm apart), then all the reflections (not just yours) are reduced.

Have a look on wiki re infinite baffle (http://en.wikipedia.org/wiki/Loudspeaker_enclosure#Infinite_baffle) if your interested, helps understand some of the variables, and there are lots depending where and what you are playing.
Hey man anything you want me to explain more let me know, I'll do my best  :thumb-up:
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 01, 2014, 05:21:47 AM
No problem man thanks for the help.  I'm going to read up on that link you posted.

Just to explain the madness a little.  I had the drums put in the corner because everything I have rad suggests that they are best there.  My cabs point into the corner simply because the drummer is there.  All around the drummer are pallets that have carpet stuck on them and stuff with foam.  We had made those things for when I was recording so they are my would be baffles.  Anyways they are in the corner now out of the way surrounding the drummer.

There will be limitations to how I can spread my cabs, I did by em to stack em like that but perhaps it wasn't a good idea.  Way easier to through two 2x12" into a small car than one 4 x 12".

Anyways thanks for helping, going to read up a bit.

Do you know what I was thinking (if it could be done), isolation spikes perhaps?  Crazy idea?
Title: Re: Too much resonant bass????
Post by: rnolan on December 01, 2014, 05:31:42 AM
Hey RG, pumping it all into a corner while seems good, is a bad idea for bass (corners boost bass, lots, so you have to compensate) in your context anyway, so double layer of drapes behind drummer in and around corner will help and I predict make it all usable. I'd start there and not overly expensive.
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 01, 2014, 09:44:05 AM
here is a random question, are drapes curtains?  Sorry man you're Australian and I'm Irish  :) we got different words for things sometimes  :o

Title: Re: Too much resonant bass????
Post by: rnolan on December 02, 2014, 05:16:00 AM
Yes, drapes re curtains thicker, big heavy carpet is better, you want thickness and biggest mass to suck up sounds (or water works well LOL , great sound absorber) e.g. people LOL, the best sound absorbers, 90 % water and they buy drinks ,... every bodies hsppy  :banana-guitar:
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 02, 2014, 06:54:03 AM
No way we have some carpet lying about, hmmmmm might be useful after all!!!

Just in the corner where the cabs are pointing?
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 02, 2014, 07:00:34 AM
I can get my hands on cushion foam or sponge as well, would this be useful, say cushions as thick as 5 inches or more and about 1ft and a half square?
Title: Re: Too much resonant bass????
Post by: rnolan on December 03, 2014, 03:13:14 AM
Hey RG, cushion foam can help, anything that absorbs the sound and doesn't let it bounce back and make reflections (which all rooms will have) and worse, standing waves where the reflections collide with the new sound waves. Spike isolation is good to stop the box coupling with the floor, between the stacked boxes you either go with it (adjust the bass to suite) or get them apart enough to stop the coupling effect (not sure how far ? further the better up to a point. getting your left right stacks as far apart as you can will help (I put my split stacks apart so the rack can still sit over the 2, so maybe a foot ?).
Hanging carpet behind the drums (well all the walls if you can) works quite well and is cheap (particularly if you have some hanging around (pardon the unintended pun)). One layer 100mm or so from the wall, and if you can another layer 100mm away from that.  Then I'd go cushions around the bottom of the wall behind the carpet starting behind the drummer
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 03, 2014, 07:34:45 AM
I wouldn't mind trying the spikes for stacks to begin with, however how on earth I'd get something like this for guitar cabs is beyond me.

perhaps I could stick some carpet between each cab and cut it out to fit?  I will bascially start sticking stuff all over the walls now as well to absorb the sound.  Dunno how I will reach the ceiling as it's really high.
Title: Re: Too much resonant bass????
Post by: rnolan on December 04, 2014, 04:04:11 AM
Hey RG, spikes for guitar cabs is overkill IMHO, they are sharp, dangerous and would be a hassle. They are typically used by audio files who want to decouple their speakers from the floor (distance) and have least contact patch (particularly for wooden floors (carpeted or shiny)) With concrete floor, you just need the distance. The milk crates you're using are fine. You'll get more bang for you buck with heavy drapes/carpet hung 100mm from the wall (air gap to the wall is important so don't stick stuff to the walls unless you have to, even the cushions will work better off the wall with gap behind). An old parachute hung under the ceiling will help also as that will help reduce the floor to ceiling standing waves.
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 05, 2014, 11:31:50 AM
I thought of a better way to separate the cabs stacked.  By putting carpet between them, so each stack, on top of the bottom cab will have a piece of carpet.

I can dampen the walls gradually as I get the material.  I also need to get the bass and stack off the floor.
Title: Re: Too much resonant bass????
Post by: rnolan on December 06, 2014, 04:27:16 AM
It's not so much the vibration between them you're trying to quell (well maybe a bit). It's the coupling of the bottom end across the boxes so needs distance (or maybe if the carpet poked out a couple of inches on the front between the cabs it might break the coupling ?, I'll ask a speaker mad audiofile friend he's across all this). So cabs on the floor couple with the floor and get a bass boost, cabs stacked without any distance in between do similar (up/down and sideways), things in corners also get a big bass boost, moving something a foot away can make a big difference.
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 06, 2014, 12:18:34 PM
Well you were right man.  I moved them apart and it sorted the issue.

I actually think the issue was so bad it was making me make mistakes.  It was so overwhelming I could feel it going through my body.  It definitely was agitating me to the point where I was making mistakes.

Anyways, I can live with it now, however I am a little disappointed that it doesn't couple up in a positive way.  The stacks both feel like I need to be in front of either one in order to hear them.  You know yourself guitar cabs are really directional but I just thought perhaps I could obtain wall of sound.  Oh well I should just be grateful I have sorted the issue.

I'm still going to pad the room out better though and get the bass of the floor.
Title: Re: Too much resonant bass????
Post by: rnolan on December 07, 2014, 02:50:04 AM
It's very difficult to give a good performance when you can't hear everything how you need/like it, I've done gigs where I got through because I new the songs note perfect, but you don't go off as well in those situations. I try to place my cab(s) so they open up on my ears (not my legs) or I end up too loud, but I also need to hear the rest of the band, and they me. So when I place us around a room, space, stage, I try to have it that we can all hear ourselves and each other (keeping in mind corners/floors that can couple and add boom/mud).
So just had an acoustic chat with my audio file mate... There's a sort of formula for this (bass boosts in rooms). So ideal (helpful) distances between things (to control (not antagonise) bass boost effects of rooms) a= distance from acoustic centre (measured from centre of cones) of cabs to floor (draw an X between the centre of the 4 12s of you L stack, is acoustic centre), b = acoustic centre to side wall, c = acoustic centre to rear wall. Ratio: a=1, b=1.5, c=2.25, but better is b=1.6 and c=2.4. It's dubbed the Allison effect, unequal path lengths.
Also to prevent box coupling, the distance between speaker cabs needs to be the same or more as the baffle size (the size of the cabs front (baffle)) When you stack 2 cabs, the baffle size doubles and give a bass boost depending on freq,~ 3db, 6 db, 12 db etc going down. To eq out (which is an option, start from 150hz and go down (depending how much eq control you have)). You could do a 150hz shelf, or if you have 3rd Octave, start with -3db at 150, -6 at 75hz, -12 at 37.5hz.
Padding the room and getting bass off the floor are good practical solutions.
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 07, 2014, 04:01:14 AM
It's very difficult to give a good performance when you can't hear everything how you need/like it, I've done gigs where I got through because I new the songs note perfect, but you don't go off as well in those situations.

I've spent most of my entire gigging career in this situation.  It got even worse now I have to wear ear plugs to preserve my hearing (musicians ones obviously).  It makes gigging incredibly unsatisfying sometimes.
Title: Re: Too much resonant bass????
Post by: rnolan on December 08, 2014, 05:37:44 AM
Hey RG, Tried the ear things years ago  (sonic noise filters) , hate them (and I mean it (hate's a strong word! but appropriate here)), they just take away ALL the energy (for me anyway). They make playing at all unsatisfying, so I've sacrificed my ears, my hearing is still very articulate, but flattened a bit.
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 08, 2014, 01:34:56 PM
Hey RG, Tried the ear things years ago  (sonic noise filters) , hate them (and I mean it (hate's a strong word! but appropriate here)), they just take away ALL the energy (for me anyway). They make playing at all unsatisfying, so I've sacrificed my ears, my hearing is still very articulate, but flattened a bit.

I can't afford to f*ck my hearing up, they are sensitive and I know they've been damaged so I have to preserve them as deafness actually runs in my family.  I blame the cymbals of drum kit entirely and possibly Motorhead  :metal:

Anyways, my big beef with them is they attenuate too much.  However, I found a set that finally reduces by a sensible amount -10db.  Most other ones are -18, -19, -20.  his is too much usually at gigs.  Practice I wear the -20db ones because we practice so loud that it all seems very loud even with -20db ear plugs in.  At gigs though the sound onstage is generally a million times lower, so if I need plugs in finally I can stick in a pair that will protect me but not lower the volume so much that I can't feel the things I'm playing and hear them in the right way.  Such a relief.  Don't want to sound like  a big wuss but I really want to be able to still mix music as audio production is hand in hand with me and the band now, I love DIY recording!!
Title: Re: Too much resonant bass????
Post by: rnolan on December 09, 2014, 03:31:15 AM
I haven't tried the modern ones, from what you are saying they may work for me (but I suspect it's too late  :facepalm: ). Cymbals killed my ears in a similar set up to your rehearsal room, it was so loud one jam that my hammer, anvil, and styrip disconnected and I was like floating (Marshall flat out cymbals pounding right next to me etc) in a basement (sound had no where to go).
BTW that whole hanging carpet thing will help, first 100mm off the wall, next 100mm again so 2 layers, will also soak up the top end from the cymbals (which is probably the most damaging)
Title: Re: Too much resonant bass????
Post by: rabidgerry on December 09, 2014, 08:22:10 AM
I haven't tried the modern ones, from what you are saying they may work for me (but I suspect it's too late  :facepalm: ). Cymbals killed my ears in a similar set up to your rehearsal room, it was so loud one jam that my hammer, anvil, and styrip disconnected and I was like floating (Marshall flat out cymbals pounding right next to me etc) in a basement (sound had no where to go).
BTW that whole hanging carpet thing will help, first 100mm off the wall, next 100mm again so 2 layers, will also soak up the top end from the cymbals (which is probably the most damaging)

I'd give them a go man, but may be your hearing i too far gone.  If you still think you hear pretty good and can do a good mix then perhaps you're ok.  I've told the boy's we're getting new rehearsal room decor lol.  Definatly standing in a garage, right next to drums is what helped mine on their way along with Motorhead.  Debbie Harry can no longer play onstage with drums as she has similar issues with cymbals.  Blondie's drummer playis with weird plexi glass deflectors surrounding his drum kit.  Crazy eh!!!  I totally understand why.

Wondeir why it's other people get screwed by cymbals and not drummers??  Mind you isn't Phil Colins screwed as well?  Perhaps that's a rumour??

It takes a while to get used to the plugs.  As I said, this new pair I got the reduce by -10db, they weren't enough for me at practice volume levels which are extreme (and it's only to compete with the drums I swear!!!)  However for gigs there is never anywehre near the same amount of volume onstage that I experience at band rehearsal so the -10db plugs are for gigs for me and should protect me just enough.  The -20db are for practice.  I only play with one amp at gigs, and never get to go full volume.  Practice I have two 150watt Crate PB's nearly at full volume, just to be at a good level with drums.  Bloody drummers!!!
Title: Re: Too much resonant bass????
Post by: rnolan on December 10, 2014, 06:00:00 AM
Hey RG, the good side is I still hear wirth good articulation (maybe years of training LOL).