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DJ EZBeats
03-04-2012, 10:15 AM
Right now I have rcf 312a for my tops. Im looking at adding a sub soon. Right now I have a qsc gx5 amp that im not using. Would it be beneficial to get an unpowered sub and utilize the amp I have, or would it be better/easier to just sell the amp and get a powered sub? I also wouldn't know exactly how to run the wires since with a powered sub, the tops would run from there, but I imagine with a passive sub, the speakers would have to run through the amp, is that right? Thanks for any input!

Incognito
03-04-2012, 10:40 AM
With the passive sub, you're going to need to also purchase some sort of processing. Either it be an active crossover & EQ or an all in one solution such as a DSP (digital signal processor) plus a rack to keep everything in. You'll end up with more control over you gear going with a passive sub & DSP (mainly due to the DSP) but you could always keep it simple & go active but you will want a sub that has a proper HPF (high pass filter) or go active & get a DSP as well & have the best of both worlds.

It comes down to your personal preference, your intended application & given budget really.

Bill Fitzmaurice
03-04-2012, 01:39 PM
Get a crossover (I assume your QSC doesn't have DSP). They're cheap and you'll greatly increase the flexibility of your system. On-board has some benefits, but IMO not enough to justify it, as you can only do what they will allow you to do. Separates allow you to do anything you want.

ampnation
03-04-2012, 01:55 PM
+1 @ what Bill said.

You could run a single channel of the GX5 with the crossover function engaged, but that won't modify the signal the RCF uses so you're likely to have a fair amount of overlap with both the sub and top reproducing something like the 70-100Hz range and that's not good.

If you got a powered sub that produced a throughput out specifically to be used by full range boxes running from the sub (HPF tailored to the sub) then you could bypass the crossover but you would be limited to that combination of cabs.

Personally, I think it is a good thing to have a crossover in your arsenal. Consider a DSP unit aka loudspeaker management unit like a driverack or BBE DS series which have extensive crossover algorithms to choose from giving you even more flexibility not to mention other features that can come in handy like limiting, parametric EQ and delay.

windspeed36
03-04-2012, 02:52 PM
Also keep in mind with the active passive combo, as you increase your overall volume you may or may not get the same increase in both the subs and tops an the ratio of bass to mids and highs may become over or underpowered

Incognito
03-04-2012, 02:56 PM
Also keep in mind with the active passive combo, as you increase your overall volume you may or may not get the same increase in both the subs and tops an the ratio of bass to mids and highs may become over or underpowered

Somewhat true since you can balance your system through your crossover or DSP. (thus that better control over the system that I mentioned earlier)

DJ EZBeats
03-04-2012, 03:18 PM
Thanks for the info all! Sounds like no matter which way I got, itd be a good idea to get a crossover/dsp. I think I might sell the amp and get a powered sub with the extra $$. Powered seems to be easier and less to haul. I think ill still get a dsp for more control though.

Bill Fitzmaurice
03-04-2012, 04:01 PM
Powered seems to be easier and less to haul. 'Seems' is the operative word. The more you learn the more you'll realize it isn't true. IMO there's only one over-riding advantage to powered, and that's if you're the manufacturer: you get to sell a speaker and an amp, not just a speaker. Right now you're already experiencing one of the main drawbacks of powered: you want to do something and they won't let you do it.

VjQue
03-04-2012, 04:18 PM
Thanks for the info all! Sounds like no matter which way I got, itd be a good idea to get a crossover/dsp. I think I might sell the amp and get a powered sub with the extra $$. Powered seems to be easier and less to haul. I think ill still get a dsp for more control though. I Have that same amp and run that and a Xover. you dont need a dsp if your only hooking up the sub. I had a powered sub but it wasn't hitting hard like the passive cab was . I also have a 4 space rack with the amp and Xover in it and the speaker wire in back. Its no different from hooking up a powered sub. Don't hook up a Eq to the sub.I have friend right now with 2 powered subs. JBL jrx118 both powered amps are bad. he got 1 fixed cost him $200 and it was something with the board. the second one he made it a passive. he's selling the powered and going back to passive.

Incognito
03-04-2012, 04:45 PM
I Have that same amp and run that and a Xover. you dont need a dsp if your only hooking up the sub. I had a powered sub but it wasn't hitting hard like the passive cab was . I also have a 4 space rack with the amp and Xover in it and the speaker wire in back. Its no different from hooking up a powered sub. Don't hook up a Eq to the sub.I have friend right now with 2 powered subs. JBL jrx118 both powered amps are bad. he got 1 fixed cost him $200 and it was something with the board. the second one he made it a passive. he's selling the powered and going back to passive.

The EQ should be in the signal chain before the crossover thus it will control the frequencies going to the sub as well, an entry level DSP can be had for the same price as a decent crossover & offer so much more then a simple crossover could.

A passive sub isn't more powerful then an active sub just on the merit of one being active & one being passive.

windspeed36
03-04-2012, 05:57 PM
I Have that same amp and run that and a Xover. you dont need a dsp if your only hooking up the sub. I had a powered sub but it wasn't hitting hard like the passive cab was . I also have a 4 space rack with the amp and Xover in it and the speaker wire in back. Its no different from hooking up a powered sub. Don't hook up a Eq to the sub.I have friend right now with 2 powered subs. JBL jrx118 both powered amps are bad. he got 1 fixed cost him $200 and it was something with the board. the second one he made it a passive. he's selling the powered and going back to passive.



I am failing to see the point of this post. As Incognito said you should always insert a graphics EQ before the crossover. You also can't compare active speakers and passive speakers as a whole against each other. A lot depends on the driver quality, design and build of the cabinet, signal quality, processing ect

VjQue
03-04-2012, 06:49 PM
I am failing to see the point of this post. As Incognito said you should always insert a graphics EQ before the crossover. You also can't compare active speakers and passive speakers as a whole against each other. A lot depends on the driver quality, design and build of the cabinet, signal quality, processing ect why run a Eq on just sub's alone. 15 or 30 band. A x-over would be better. for what he's doing

DJ EZBeats
03-04-2012, 07:03 PM
Well what Im more so be considering now is getting a powered sub, and getting an dsp that would act as a xover and eq. This seems to be the best option for the most control, correct me if im wrong? I can sell the amp and get a driverack for about the same price. Looking at this one http://www.guitarcenter.com/dbx-DriveRack-PA-Processor-183588-i1828499.gc

Also wasnt trying to compare passive to active. Just trying to decide the best direction to go in to maximize my budget and sound quality.

ampnation
03-04-2012, 07:11 PM
I was watching a video from Dave Rat about live sound EQ'ing and he made a good point. Some of this is applicable to DJ's with recorded music too.
Use the channel strip EQ to adjust for input device distortions.
Use processors to adjust for amp/speaker distortions.
Use Graphic EQ to adjust for room anomalies.
With this approach, you get to know your input settings and if your setup doesn't change much, you can just leave them set; your processors would never change because your amps and speakers are always going to have the same basic distortions every day; leaving just an EQ adjustment when you move from venue A to venue B.
This approach enables you to re-adjust settings quickly with the substitution or addition of any piece of equipment -- probably more appropriate like I said to live sound which is Rat's forte, but many of us run both, so good for people like me.

windspeed36
03-04-2012, 07:29 PM
I was watching a video from Dave Rat about live sound EQ'ing and he made a good point. Some of this is applicable to DJ's with recorded music too.
Use the channel strip EQ to adjust for input device distortions.
Use processors to adjust for amp/speaker distortions.
Use Graphic EQ to adjust for room anomalies.
With this approach, you get to know your input settings and if your setup doesn't change much, you can just leave them set; your processors would never change because your amps and speakers are always going to have the same basic distortions every day; leaving just an EQ adjustment when you move from venue A to venue B.
This approach enables you to re-adjust settings quickly with the substitution or addition of any piece of equipment -- probably more appropriate like I said to live sound which is Rat's forte, but many of us run both, so good for people like me.
Yay, im not the only one on these forums that watches the stuff from Dave. :)

windspeed36
03-04-2012, 07:32 PM
why run a Eq on just sub's alone. 15 or 30 band. A x-over would be better. for what he's doing
What? You make no sense, I said if your going to implement a graphics EQ, then it is best done before the signal enters the crossover

Incognito
03-04-2012, 09:07 PM
Yay, im not the only one on these forums that watches the stuff from Dave. :)

Yes, I remember this same Youtube video from Dave as well as a few others. When I tune my system I follow this same rule but it's easier for me since my speakers are pretty much flat without any EQ correction so this leaves me to just tune to the room then make only the fly track EQ corrections from my main board.

Incognito
03-04-2012, 09:08 PM
What? You make no sense, I said if your going to implement a graphics EQ, then it is best done before the signal enters the crossover

I was a little baffled by his statement as well since I thought it was pretty clear where the EQ should fall in the signal chain but then again this confusion further strengthens my statement for using a DSP instead, (especially for those who don't know how to process their signal chain) since the DSP "knows" where to place the EQ in the signal chain..