yamaha emx5000 powered desk and a hk audio vx2400 poweramp

puremule · 03-10-2006 2:51pm #1

hi can anyone help. i want to try and attach my poweramp to my powered desk to basically give me all the power coming from one source.any ideas? and also i am using the hk audio p:ro series with 15" tops and 18" bins but the power amp seems to be clipping a lot. Theres a 500watts a side in the desk and 1200 watts a side in the power amp so in my mind this is ample power. any ideas or suggestions would be greatly appreciated!!

Eoin Madsen · 03-10-2006 4:04pm

Okay, for one, there's no (simple) safe way to combine the poweramp outputs - they won't share a load properly and one or other or both will get damaged. Secondly, in a two-way system you're most definitely better off with seperate amps anyway.

Power the bass drivers with the 1200 watt amp, and the tops from the powered mixer. If you use an electronic crossover you'll get far better performance from the amps - at a guess, this is what's missing from your setup.

For the best gain structure you should trim the poweramp inputs down so that they clip at the same level as the main mix outputs on the mixer - this way the VU meter on the desk should be directly related to the amp power.

david · 03-10-2006 4:41pm

This is a tough one, you cant really use an x-over with a powered desk. What im thing is run a stereo master send from the desk to a crossover with the mix on full, then return the HF x-over outs to the desk and bring the LF x-over outs to the amp and bins, then run the main tops from the master powered outs on the desk. That should work in theory, but it also rules the posibility of a decent sound desk recording out, should you wish to run a FX-return to a minidisk/HD recorder.

Eoin Madsen · 03-10-2006 6:10pm

How you return the hf from the crossover to the powerstage of the desk is the only part that needs to be troubleshooted. It really depends on the powered desk, but there's usually some way to insert between the mixer and the powerstage.

Savman · 03-10-2006 6:53pm

Eoin Madsen wrote:

there's usually some way to insert between the mixer and the powerstage.

I know the Dynacord powered desks allow this kind of config but when I had a Powermate I never bothered, just seems like a pain in the ass. It seems as though the OP just realised the problems with expanding on powered desk set-ups...

puremule wrote:

hi can anyone help. i want to try and attach my poweramp to my powered desk to basically give me all the power coming from one source.any ideas? and also i am using the hk audio p:ro series with 15" tops and 18" bins but the power amp seems to be clipping a lot. Theres a 500watts a side in the desk and 1200 watts a side in the power amp so in my mind this is ample power. any ideas or suggestions would be greatly appreciated!!

You'd nearly be better off using the poweramp on its own if its 1200w per side. The HK Premium Pro range have a passive crossover in the subs iirc so all you need is a speakon out to the Tops. That's the way that system is designed and supposed to be hooked up and probably the best/easiest way to get the most out of it.

david · 03-10-2006 7:02pm

Well i think biamping would be better with a decent active x-over, if theres a master insert it could easily be done...

Savman · 03-10-2006 10:35pm

freakonaleashx wrote:

Well i think biamping would be better with a decent active x-over, if theres a master insert it could easily be done...

Sure it can be done but why would that make it better

the power amp seems to be clipping a lot

There's the problem right there! All I'm saying is that rig is built so that the subs, via passive built-in crossover, send the required thru signal to the Tops. It whacks out 900w RMS @ 4ohm per side according to the HK site spec so if the OP has a 2400w poweramp it is more than capable. It's just mathematics tbh. The desk's outputs would be wasted but that's the gig with powered desks when you try add-on.

david · 03-10-2006 10:57pm

Why is bi-amping with an active x-over better?

Well for one you have seperate amps driving your high-mids and lows, which means more wattage/headroom/clarity. I presume both power amps have input attenuators which allows you to set up correct gain staging for both highs and lows. You can compensate for a boomy sounding room by rolling off the sub volume and also with the x-over you can tune the x-over frequency to your particular needs. 150Hz on a passive crossover (in the HK sub) seems a little high to me, I usually run subs at 90-120Hz depending on the job. Naturally enough with >150Hz being at the bottom end of the audible spectrum, you'll want about twice the wattage of the tops to get them heard.

Also AFAIK HK premium PR:O speakers are rated at 4 ohms a piece. If you run that amp into the subs with the tops in line (which is how i presume the x-over is wired) you'll get a total load of 8ohms running from a 2x1200w @4ohm amp. Im only estimating here, havent seen the spec sheets but i'd imagine this would cut the total output to about 700w per side at 8ohm. Not a good idea if the gear at your disposal is capable of more.

I'd hardly say biamping is any more awkward than buying another unpowered desk to run an inferior rig as opposed to spending another 150 quid on a 1U x-over and a few patch cables presuming the OP doesnt already have one.

Savman · 04-10-2006 1:53am

freakonaleashx wrote:

I'd hardly say biamping is any more awkward than buying another unpowered desk to run an inferior rig as opposed to spending another 150 quid on a 1U x-over and a few patch cables presuming the OP doesnt already have one.

I dunno, I had to do something similar with my last rig and it got to the point it was such a hassle I just sold the whole set-up. I had xlr's and jack's all over the place and it became cable city, not something I'd recommend to anyone setting up and taking down gear on a regular basis.

You can compensate for a boomy sounding room by rolling off the sub volume and also with the x-over you can tune the x-over frequency to your particular needs.

The best sound shaping tool for room compensation is a graphic or parametric EQ, rolling off sub volume doesnt really help solving problematic frequencies in awkward rooms. Granted you can set the crossover as desired but for me it was a needless accessory. I suppose its all much of a muchness and I just didnt get on with the active crossover set-up.

Now that I've re-read the original post, I see this...

i want to try and attach my poweramp to my powered desk to basically give me all the power coming from one source

:eek::eek: Crossovers dont come into the equation, he wants to combine all his power into one

Er, nothing further to add

:D:D

david · 04-10-2006 1:58pm

Well technically biamping is combining the total power available

.

Savman · 04-10-2006 3:12pm

don't think the OP cares anyway bud! hasn't been back since!

puremule · 04-10-2006 6:22pm

thanks for all the suggestions guys. nay more ideas will be greatfully received.....cheers:

yamaha emx5000 powered desk and a hk audio vx2400 poweramp

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