Sub Advice

[Twinspin]

How I understand it you would need a BUS built in the mixer (Can route specific audio signals) to a specific output

[Nakatomi]

You can do this kind of thing if the mixer has an Aux bus, or aux sends. Sometimes they're only mono though, so watch out for that.

[pitdiver]

Here is the spec for the Alto
http://www.altoproaudio.com/products/zmx122fx

As for amps KAM KXR 150V2+ KAM KXR 300V Remember guys I tend to do very small gigs in our local Village Hall and also supply PA for Bingo night and the such like.

[ukpartydj]

It's still worth pointing out here that merely running subs in parallel with mid/tops, if they're not matched maybe isn't a good idea. It isn't just about the load impedance the amplifier sees it's to do with frequency response.

Say you have an all passive pa and your mid/tops go down to 70Ha and the subs reproduce up to 150Hz. The overlap can produce a hump in the overall system frequency response. In some cases if the cabs are well matched it can work well, but if not, your bass end can be uneven & boomy on some notes.

The same applies if you can't tune active speaker frequency response too. An active crossover either on the sub or independent, can alleviate this. The alto sub does indeed have a true active crossover meaning that audio at the input is split between the sub and mid/tops around the crossover frequency. The QTX sub on the other hand passes all frequencies to the 'through' output as far as I can tell meaning that you can't roll the bass end off the mid/tops unless they have a control onboard to do this themselves. You can adjust the highest bass frequency the qtx sub reproduces but that isn't as good as a proper crossover. Also, the alto active subs can take a stereo signal into one sub and output mid/top to a stereo pair. The qtx subs cannot.

I'm pretty sure it doesn't roll the bass off ... however it works for some people like me because:

Mackie SRM450's tail off at 80hz ....... 45hz it's -10db
RCF 310a tail off at 85hz ........ 65hz it's -10db but more importantly at 80hz it's -2db

I use the RCF's with the QTX subs so by setting the maximum reproduced by the QTX subs to 80hz (roughly) the amount of crossover between the two is barely anything at all.
With my RCF's I'm not trying to take the load off them though, I'm trying to add bass.

When I do larger events the RCF tops always go through the RCF sub with the crossover.

Actually thinking about it ... the Mackie SRM450's are -10db at 45hz, and the Alto's are -10db at 47hz ... isn't that worse than the mackie ??? Is that what you were trying to say?
Might as well but a mackie on the floor and put a low pass filter on it!

[Nakatomi]

I'm pretty sure it doesn't roll the bass off ... however it works for some people like me because:

Mackie SRM450's tail off at 80hz ....... 45hz it's -10db
RCF 310a tail off at 85hz ........ 65hz it's -10db but more importantly at 80hz it's -2db

I use the RCF's with the QTX subs so by setting the maximum reproduced by the QTX subs to 80hz (roughly) the amount of crossover between the two is barely anything at all.
With my RCF's I'm not trying to take the load off them though, I'm trying to add bass.

When I do larger events the RCF tops always go through the RCF sub with the crossover.

Actually thinking about it ... the Mackie SRM450's are -10db at 45hz, and the Alto's are -10db at 47hz ... isn't that worse than the mackie ??? Is that what you were trying to say?
Might as well but a mackie on the floor and put a low pass filter on it!

On paper it doesn't look as if even the alto sub would add anything. Unless I'm proved otherwise I'll be saving for something better.

Do your qtx subs make a difference worth having? I'm guessing that almost an extra octave of low end will improve the sound but is it worth it for the extra lugging around & wiring up? I need a demo, I think.

[Andy P]

Having used the QTXs myself I would definitely say the add something even if on paper the frequency range isn't increased. On the flip side after a year they do self destruct inside

[ukpartydj]

On paper it doesn't look as if even the alto sub would add anything. Unless I'm proved otherwise I'll be saving for something better.

Do your qtx subs make a difference worth having? I'm guessing that almost an extra octave of low end will improve the sound but is it worth it for the extra lugging around & wiring up? I need a demo, I think.

Well the RCF 310a's have very little bass in my opinion so it may not be the best example. When I pack away I sometime leave a track on in the background and when I turn the sub off you really notice the difference.
I'd imagine with the SRM450's you don't need as much of the mid-bass added so my theory is you could achieve more volume from the QTX sub... maybe?

If I'm feeling it at the weekend I might use my Mackies and the QTX to see if they work well together.

[Nakatomi]

Well the RCF 310a's have very little bass in my opinion so it may not be the best example. When I pack away I sometime leave a track on in the background and when I turn the sub off you really notice the difference.
I'd imagine with the SRM450's you don't need as much of the mid-bass added so my theory is you could achieve more volume from the QTX sub... maybe?

If I'm feeling it at the weekend I might use my Mackies and the QTX to see if they work well together.

Yup. I think I'm definitely going to need to have a demo with my SRM450s somewhere. I can't see me carrying around two 45 kilogram subs until I've got a van & a little helper.