Hi there

I'm running a tri-amped PA at the moment, subs and bi-amped top boxes. The subs are crossing at 125, and the HF at 1.5. When I was sound checking tonight I had the kick drum going through only, with no other noise on stage, and when I looked at the amp rack, the sub amp was showing a good signal, but so was the mid amp.

Sould this be? The PA sounded great, but I'm concerned I'm looking headroom in the mids. There was plenty of headroom left in the sub amp, and top amp but not in the mid amp.

Please advise!

Cheers folks. Rich

Hi Rich!

First off - a kick drum doesn't JUST produce sub - it's not unusual for significant energy to be present in the mid and high ranges - that's partly what gives the "punch" to recorded mixes, for incidence. I'd expect lots to be going on in the 20-500Hz, less in the mid up to a peak at around 2-3K, then less again higher up the scale, tailing off beyond 10K, unless you're using any kind of distortion effect to add punch (such as a valve preamp, etc). So in short, there shouldn't be much to worry about.

Assuming you're using an active crossover, I'd be checking that the subs are in low-pass, mids are in band-pass, and the highs on high-pass. Sounds obvious, but I've hired many a "pre-configured" tri-amp system with dedicated speaker management units, only to find that the mids are in low-pass, with no roll-off to allow for the subs!!!

If you have plenty of sub-headroom and want to increase mid headroom even more, you *could* experiment with setting the crossover point between subs and mids a little higher.

I'm also a little surprised to see your HF being 1.5K and above - I'd normally expect a 3K cross-point between MF and HF - but I could be a little jaded by the amount of studio/hifi stuff I've been doing of late.

Hope this helps/encourages

C.

I'm with solstace - 1.5 does seem a bit low - the horns in my systems are pretty poor below 2k, they smooth out nicely at about 2.2-2.5.

re: the kick. I've also found that a wooden beater creates a click that reaches up very high - just over 6K if the skin is tight.

That's put my mind at rest! I was under the impression that that a kick drum was only really present at 63Hz - obviously I couldn't have been more wrong!

I'll try and cross them a little higher

As for the tops, the compression drivers are JBL 2446's, and the recomended crossover just says 500Hz or higher, and as I've got Eminence Kapa's in the mids, I was trying to compensate for the fall off on the drivers. However, I'll try crossing them higher and see how that sounds.

Thanks for you help guys.

All the best. Rich

Yeah.

The "Click" of the beater hitting the skin of the Kick Drum would usually be around 1kHz sort of area, so yeah, I'd expect that to definitely be in your mids.

In my experience anyway.

Si

I agree with Si.

The 'thump' of the kick is much much lower typically (really depends on the drum and how its tuned though), but the beater on the skin does make a definate 'snap' which becomes more noticible the closer you put the mic to the skin.