P.A Bass Bin / Sub's question - running bass guitar

[Me And My Bass]

Sorry if this is in the wrong section guys.

My band uses a 4K rig and just now we are running everything through it. I know how much the bass guitar/kick drains the power, Im thinking of taking some of the load off the main rig and applying another system for running my bass (& possibly kick drum etc).
Should l be looking at Subs or more bass bins? What would give me the best sound?
I want to use our Allen & Heath PA-28 desk with the new set up, im thinking of using a AUX Send to the new subs/bins amp on the bass channels.

Anyone any views or pointers on this?

Cheers,

Jab!

[thinman]

[quote name='Me And My Bass' post='755421' date='Feb 23 2010, 08:19 PM']Sorry if this is in the wrong section guys.

My band uses a 4K rig and just now we are running everything through it. I know how much the bass guitar/kick drains the power, Im thinking of taking some of the load off the main rig and applying another system for running my bass (& possibly kick drum etc).
Should l be looking at Subs or more bass bins? What would give me the best sound?
I want to use our Allen & Heath PA-28 desk with the new set up, im thinking of using a AUX Send to the new subs/bins amp on the bass channels.

Anyone any views or pointers on this?

Cheers,

Jab![/quote]

What have you got already in terms of power amps, crossovers and cabs etc?

[Me And My Bass]

[quote name='thinman' post='755548' date='Feb 23 2010, 09:40 PM']What have you got already in terms of power amps, crossovers and cabs etc?[/quote]

Running X 2 Crown XTi 1000 amps for the tops & X 1 XTi 2000 amp for the Subs. Built in X-over. The 2 tops are 1k each JBLs, so are the JBL bins.

Edited February 23, 2010 by Me And My Bass

[Phil Starr]

It depends on what you are trying to do. This is a already pretty impressive set up. The jbl's i find a bit bass heavy if anything and you already have subs. does your sound engineer have any indication that you are running out of bass grunt. is the XTi 2000 clipping?

If you just add subs then you will only get extra sound below the crossover frequency and your sound wont be any louder psychologically, it will just get more gut wrenching which is fine if that is what you want to achieve. A bass bin which has a higher crossover frequency would beef up the bass and possibly reduce the demand on the PA but it will change your tone so that it becomes a lot deeper again this is fine if you want that effect. If you just want to be louder or to maintain the same volume then you will need either a bass speaker (which you can put out front to keep the sound off the stage) or to beef up the whole PA,

If your PA isn't clipping you don't need to do this and you can put your money towards something else

[Me And My Bass]

[quote name='Phil Starr' post='755698' date='Feb 24 2010, 12:20 AM']It depends on what you are trying to do. This is a already pretty impressive set up. The jbl's i find a bit bass heavy if anything and you already have subs. does your sound engineer have any indication that you are running out of bass grunt. is the XTi 2000 clipping?

If you just add subs then you will only get extra sound below the crossover frequency and your sound wont be any louder psychologically, it will just get more gut wrenching which is fine if that is what you want to achieve. A bass bin which has a higher crossover frequency would beef up the bass and possibly reduce the demand on the PA but it will change your tone so that it becomes a lot deeper again this is fine if you want that effect. If you just want to be louder or to maintain the same volume then you will need either a bass speaker (which you can put out front to keep the sound off the stage) or to beef up the whole PA,

If your PA isn't clipping you don't need to do this and you can put your money towards something else[/quote]

Thanks for your reply Phil,

Yeah the XTi 2000 does clip (and sometimes cut itself off altogether when we are pushing it!). The problem being the vocalists level is hot as well, we have compressors in place though for him. I think possilby adding the bins is the best way to go then just for the bass rig and kick drum, that would free up the main rig for all Vocals, accustic guitar, sax, electric guitar & some kit.
I do the sound live from the stage (we are only playing bars and small/medium clubs), l would love a soundman to do it though!
Am l on the right track if l was going to go ahead with the extra bins, using an Aux channel for that mix to them?
Any ideas for what l should be looking for? Im thinking two 500 bins and an 1k amp for them. Im currently using an Agulier DB410 & 500SC amp which can hold its own onstage.
Anyone selling any bins?

Cheers,

Jab!

[High score]

[quote name='Me And My Bass' post='755862' date='Feb 24 2010, 10:04 AM']Thanks for your reply Phil,

Yeah the XTi 2000 does clip (and sometimes cut itself off altogether when we are pushing it!). The problem being the vocalists level is hot as well, we have compressors in place though for him. I think possilby adding the bins is the best way to go then just for the bass rig and kick drum, that would free up the main rig for all Vocals, accustic guitar, sax, electric guitar & some kit.
I do the sound live from the stage (we are only playing bars and small/medium clubs), l would love a soundman to do it though!
Am l on the right track if l was going to go ahead with the extra bins, using an Aux channel for that mix to them?
Any ideas for what l should be looking for? Im thinking two 500 bins and an 1k amp for them. Im currently using an Agulier DB410 & 500SC amp which can hold its own onstage.
Anyone selling any bins?

Cheers,

Jab![/quote]


You got your work cut out doing the desk from stage so all credit to you.

You got a really good rig however a good rule of thumb is having bass power twice that of your tops so it may be a little underpowered if you ever need to stretch the PAs legs in a larger venue. You can add more bass to this rig fairly comfortably but may need another speaker, amp and cross over to do it.

I would also suggest experimenting with the bass eq on the desk before investing in more expensive (and heavy) gear. This might allow you to place it better within the mix and certainly help reduce clipping. Remember that when you add more on the EQ the signal is hotter - less is usually more so try cutting and not adding on the EQ.

I would also suggest you read up on gain structure as you may not be optimising the gear you have. The indication that you are tripping through overload means you have not set the gain structure up properly for your PA and will sadly burn it out eventually. I can post you some good guides if you can't find this info.

Good luck.

Iain

Edited February 24, 2010 by High score

[thinman]

If you went for aux-fed subs you would probably just send the kick drum and your bass to the subs. That might give you the option of putting a limiter or compressor in line to both protect your amp a bit and increase the preceptual loudness of the bass end.

For small clubs and bars it still seems like a lot of power.

You might be able to find some more efficient subs too. I built some Bill Fitzmaurice T39 horn-loaded subs which are a lot more efficient than direct radiators or rflex systems. Big though!

[Phil Starr]

I think you've got us all thinking here. You are running more power than most of the rest of us but if your amp is clipping and shutting down then clearly you have to fix things. What impedance are the bins? If they are 8 ohms then you will only be getting half the rated power through the Crown. The clipping light will be voltage dependant so no worries but the shut down could be dependant on the current or the voltage from the amp.

What I am thinking is that if the subs are 8 ohms you can add two more and run them off the existing amp. This will give you an extra 6dB which is the same as increasing the amps power by 4. Basically running the extra speaker will draw double the power from the amp and the extra speaker surface area will improve the coupling with the air at low frequencies and increase the efficiency.

Ok I've done some checking and the Crown only gives 1000W into 2 ohms 800 into 4 and 475 into 8. Which bass bins are you using?

The idea of using some compression on your bass bins is a good one it will give more punchiness and you can move the average sound levels higher without peaking out. If you have a limiter on the compressor it will cut the peaks out as well which will be almost inaudible at these frequencies. Several manufacturers are starting to build this trick into their active subs now. The other trick while you figure this all out is to cut the bass a little on the mixer. 3dB will only just be noticeable and will give your amp a lot of breatjhing space. If the amp has a subsonic filter then use it losing everything below say 40Hz won't really affect your music unless you use a lot of synth and again reduces the load on your amp.

I assume the subs are on the floor, this doubles their efficiency at low frequencies and moving them against the side walls will also help.

It is really hard to mix from the stage. Do you have someone you trust who will give an honest opinion of your sound? You may be sounding better than you think or even bassier than you think.

[crez5150]

Can I just ask.... have you adjusted any of the DSP settings? Have you got the correct pre-sets for your JBL speakers loaded? May be worth checking the DSP software. If you have not already I would download the latest version of Band Master (HiQNet) software and alter some of the settings, particularly the input gain settings as they are generally set lower than you would normally want.....