Why am I struggling to make bass sound good through PA?

[mrtcat]

We have a great PA (rcf 932a x2 and rcf 905 sub x2) and a capable mixer (XR18) and yet im never happy with the bass sound through PA. 

 

I have a Darkglass Anagram which sounds amazing for recording direct into a PC and awesome on the multi track live recording we take direct from the desk at gigs. It also sounds perfect in my iem mix. My amp is a Darkglasd M900 and my cab is a greenboy F112. That setup sounds killer too.

 

Why is it then that the bass sound coming out of the PA just always seems to sound a bit woolly and soft and lacking those lovely clean piano type lows. Even if I turn all processing off on the desk it seems to sound like it lacks the clean weight of sound and crisp top end. Do I just need to be braver with the eq or is it something in the PA speakers that hates me?

[Bill Fitzmaurice]

PA subs go as much as an octave lower than bass cabs, while PA mains don't have the rising midrange typical of bass cabs. Try high passing the desk bass channel at 60 to 80Hz, if it has that capability, or cutting back on the bass EQ if it doesn't, while boosting the mids in the 2 to 2.5kHz range. 

 

If you want to be more precise get this app for your phone. https://play.google.com/store/apps/details?id=com.dom.audioanalyzer&hl=en_US&pli=1

You can use it to see the frequency response of your rig. Play an open A and take a picture of the result, C weighting, slow response. Save it and compare it to the same test through the PA. Comparing the two will show where the PA EQ needs to be adjusted. 

Edited yesterday at 21:32 by Bill Fitzmaurice

[mrtcat]

8 hours ago, Bill Fitzmaurice said:

PA subs go as much as an octave lower than bass cabs, while PA mains don't have the rising midrange typical of bass cabs. Try high passing the desk bass channel at 60 to 80Hz, if it has that capability, or cutting back on the bass EQ if it doesn't, while boosting the mids in the 2 to 2.5kHz range. 

 

If you want to be more precise get this app for your phone. https://play.google.com/store/apps/details?id=com.dom.audioanalyzer&hl=en_US&pli=1

You can use it to see the frequency response of your rig. Play an open A and take a picture of the result, C weighting, slow response. Save it and compare it to the same test through the PA. Comparing the two will show where the PA EQ needs to be adjusted. 

Thanks so much Bill, that makes perfect sense. I've downloaded the app and will give it a go today. 

[dudewheresmybass]

17 hours ago, Bill Fitzmaurice said:

PA subs go as much as an octave lower than bass cabs, while PA mains don't have the rising midrange typical of bass cabs. Try high passing the desk bass channel at 60 to 80Hz, if it has that capability, or cutting back on the bass EQ if it doesn't, while boosting the mids in the 2 to 2.5kHz range. 

 

If you want to be more precise get this app for your phone. https://play.google.com/store/apps/details?id=com.dom.audioanalyzer&hl=en_US&pli=1

You can use it to see the frequency response of your rig. Play an open A and take a picture of the result, C weighting, slow response. Save it and compare it to the same test through the PA. Comparing the two will show where the PA EQ needs to be adjusted. 

Great advice!

[Al Krow]

18 hours ago, Bill Fitzmaurice said:

PA subs go as much as an octave lower than bass cabs, while PA mains don't have the rising midrange typical of bass cabs. Try high passing the desk bass channel at 60 to 80Hz, if it has that capability, or cutting back on the bass EQ if it doesn't, while boosting the mids in the 2 to 2.5kHz range. 

 

If you want to be more precise get this app for your phone. https://play.google.com/store/apps/details?id=com.dom.audioanalyzer&hl=en_US&pli=1

You can use it to see the frequency response of your rig. Play an open A and take a picture of the result, C weighting, slow response. Save it and compare it to the same test through the PA. Comparing the two will show where the PA EQ needs to be adjusted. 

 

Hi Bill, excuse my ignorance but could you elaborate on what you mean by "rising mid range" for me please?

[JPJ]

Just a thought, but before you worry about eq, are you sure you have the gain set right, and that all of your Anagram patches are putting out the same level?

[Bill Fitzmaurice]

1 hour ago, Al Krow said:

 

Hi Bill, excuse my ignorance but could you elaborate on what you mean by "rising mid range" for me please?

Look at the frequency response chart here, which is a typical high quality bass driver. Note the midrange that peaks at 2.5kHz. 

https://eminence.com/products/kappalite_3012ho#frequency-response

 

[Dan Dare]

Bill's advice is spot on, as always. I'd suggest using the HPF at 60-80hz on everything in the PA, not just the bass. You won't block all frequencies below that figure, because the roll-off will most likely be at 6, 12 or perhaps 18db per octave. It will make the overall sound a lot cleaner. People tend to over-use PA subs and put too much low frequency energy into a room, which results in mud and boom city and can excite all sorts of nasty resonances in a room that isn't acoustically treated (which applies to most gig venues).

[Bill Fitzmaurice]

Most top acts tend to over-use subs as well. I'd say three out of four FOH mixers have no idea how to mix bass. The fourth is a bass player. ☺️

[Buddster]

That's a great app, thanks Bill