Micing a 2-way cab for live?

Dark Barn · #1 09-20-2010, 11:23 AM

Soon I will be getting a 2-way crossover'ed speaker box with a woofer and mid-range driver.

I'm curious as to whether or not it will ever be practical to mic such a set-up for live sound, and if so what sort of micing arrangement would be ideal for it. Thanks!

billfitzmaurice · #2 09-20-2010, 11:25 AM

The best method is to mic the midrange, use DI for the lows, mix the two at the board.

Dark Barn · #3 09-20-2010, 11:34 AM

Thanks Bill, damn you're fast!

I guess my next question is, if a DI is being used isn't it at that point more expedient to just use the DI only? I somewhat don't look forward to being a special needs musician when it comes to dealing with the soundman.

I generally defer 100% to the wishes of whoever is doing sound, but if a sound guy were to hypothetically prefer to mic my cab over using a DI would it ever be practical to do so? With 2 mics?

gastric · #4 09-20-2010, 11:52 AM

I ran into this same issue when using my 4-way Accugroove El Whappo Jr. Sound guys had no idea what to make of it so I always ran DI. Which meant I was using the Whappo Jr for a really expensive stage monitor that only I was hearing. It's a head scratcher.

brendanbassist · #5 09-20-2010, 12:00 PM

Quote:

Originally Posted by billfitzmaurice

The best method is to mic the midrange, use DI for the lows, mix the two at the board.

I've never tried it live, but when I tried to mix a DI signal with a mic'd signal while recording, I got some phase issues. This can be tweaked by slightly delaying the DI signal with the recording software, but how would you get around that live?

rpsands · #6 09-20-2010, 12:06 PM

Be sure to compare the quality of a straight DI vs DI + mic. I tend to prefer the former.

**lowfreqgeek** · #7 09-20-2010, 12:12 PM

Quote:

Originally Posted by brendanbassist

I've never tried it live, but when I tried to mix a DI signal with a mic'd signal while recording, I got some phase issues. This can be tweaked by slightly delaying the DI signal with the recording software, but how would you get around that live?

There are a number of phase alignment tools. Radial makes one, and the first one I know of was from Little Labs. It's actually a very simple circuit, and could be wired into a little project box no problem.

The other option is that the sound person could put a little delay on the DI'd signal at the board. However, it would depend entirely on the tools, capabilities, and competency of the sound person. What's the speed of sound? How close is the mic from the speaker? Can they even hear it (too many "sound men" are shy on ears...)?

I've worked with a few very competent sound guys, but most are less than competent at the level I usually play (clubs, some casinos, etc).

**Ukiah Bass** · #8 09-20-2010, 02:07 PM

I did tested various mics and positions on my 15/6 cab. Details, photos, and recordings are here.

Mic’ing the LDS 15/6 bass cabinet

Eric Moesle · #9 09-20-2010, 02:18 PM

Quote:

Originally Posted by brendanbassist

I've never tried it live, but when I tried to mix a DI signal with a mic'd signal while recording, I got some phase issues. This can be tweaked by slightly delaying the DI signal with the recording software, but how would you get around that live?

I use one of these live to remedy the phase-cancellation issue. Works great, and the setting needs to be adjusted at each gig, because the distance between the bass cab and the PA cab changes and affects the phase differential at each location.

This little box is worth every penny if you prefer to mix a mic and DI line:

http://www.americanmusical.com/Item--i-RAD-PHAZER

Bassmec · #10 09-20-2010, 03:50 PM

These are the original and still the best in my opinion.
http://www.mercenary.com/litlabibpanp.html

billfitzmaurice · #11 09-20-2010, 04:16 PM

Quote:

Originally Posted by Dark Barn

Thanks Bill, damn you're fast!

I guess my next question is, if a DI is being used isn't it at that point more expedient to just use the DI only? I somewhat don't look forward to being a special needs musician when it comes to dealing with the soundman.

I generally defer 100% to the wishes of whoever is doing sound, but if a sound guy were to hypothetically prefer to mic my cab over using a DI would it ever be practical to do so? With 2 mics?

The coloration that defines tone comes from the mids, and much of that coloration is speaker sourced, so if you want that coloration in the PA too then you need to mic the midrange driver, or the woofer if you have no midrange driver. There's little benefit in separately miking the low end with a two way cab, and doing so can introduce complex phase issues with the two sources. Using a DI for the low end also eliminates low end stage noise, especially from the drums, as mics aren't as directional in the low end as in the mids.

Quote:

There are a number of phase alignment tools...

The other option is that the sound person could put a little delay on the DI'd signal at the board.

+1, phase and time are essentially the same thing. But there's no phase issue if you simply low pass the DI signal and high pass the mic. It's when you try running both full range that things get hinkey.

fokof · #12 09-20-2010, 10:17 PM

Quote:

Originally Posted by billfitzmaurice

+1, phase and time are essentially the same thing. But there's no phase issue if you simply low pass the DI signal and high pass the mic. It's when you try running both full range that things get hinkey.

^^^^+1

Problem is that most of the real "working places" board have rarely a variable HPF , even less often a Variable LPF.

Can't live without my Phazer!