Axiom Home Page Forums General Discussion Technical Questions M22 full range roll off with Sub

Hey guys,

Just a quick question. I am planning using the M22s for studio monitors, and was wondering if you guys could confirm my thoughts.

I am going to be using a monitor switching device, have the M22s on A and the EP400 (or EP350) on B. I want to be able to run the M22s full range, and also add the sub for mixing. Basically I want to be able to switch between the M22s only, full range, and then add the sub to the M22s. Would I be able to let the M22s roll off naturally, and not cross them over to the sub with a hard cross over? The sub will be filtered at 80hz, but the M22s will be full range. Would using 60hz on the sub provide a better mix? I am worried about the 60-80hz range having a hump since the M22s are responsive down to 60hz and if the Sub is filtered at 80hz, both the sub and the M22s will be playing the 60-80hz range.

I hope I make sense, I have been researching this for weeks, and just wondering what you guys think.

I think that - by using the crossover on the sub - you could make it work.

You could run some sweeps with both the M22 and EP400 on and adjust the sub crossover until you get it blended to your taste.

I guess I need to try REW with the M22's set to large and the sub crossover set to 80 or 60 and I will let you know. Now I just need the time to try it.

REW? Jason, that would be great if you could try it out for me and give me your impressions. I don't want to cut off the M22s as I want to be able to use them as full range for mixing, and combine them with a sub on and off while mixing.

So when I run the sweeps I would be looking for the flatest response DB wise through the crossover right?

Also guys, do you know if I use the High Level inputs on the sub, will that degrade the sound quality to the M22s?

Another one, I am noticing there is only one XLR input on the DSP subs, I need a L/R input for both channels into one sub, I really cannot believe that axiom doesn't have L/R inputs with RCA, and L/R inputs for XLR...that may be the deal breaker for me, I really want to get axiom but I am not sure I'll be able to.

There's a left and right channel for subs?

there is when its in studio use, 2 channels, 2 monitors, two outputs that need to goto one sub (via balanced or unbalanced).

I'm curious. Why the need for two outputs for studio use?

Two outputs, why not use 2 subs?

CV: Most of the time I am using a 2 or 3 sounds for the bass (for pop and hip hop stuff). I occasionally like to pan those different samples a bit to the left and right to open up the centre image (to make the centre image less congested to make room for the lead). Same with kick drums. So it is important to have a stereo mix of the LFE going to the sub.

Jason: I would love to use 2 subs, but for now it is out the financial equation. I was checking out the HSU subs, they have the new ULS-15 that is a sealed design, with two XLR inputs that I might purchase for around the same price as the EP400, except it comes with 1000 watts...

Can't you just combine the L/R signals into one going into the one input on the sub?

And by all means, get four of those USL-15s as soon as you can afford them. We want reviews.

CV, it could provide just another link in the audio chain that could cause problems. I have actually looked for a device that will combine dual TRS into one, but haven't come across anything.

If it's not combined outside of the sub, isn't it just combined within the sub? Sorry for all of the questions. I'm really curious.

I was thinking of the Hsu subs when I mentioned that.

CV: I am out of answers!! I wish I knew.

My M22's and HSU STF-2 are powered by a Harmon Kardon 3490 stereo receiver. The HK has two subwoofer outputs, but they run full range (no crossover in the receiver). The sub is connected to one of the HK's subwoofer outputs (low level)and I use the sub's crossover set at 60hz...with the M22's running full range. The sub blends seamlessly with the M22's.

No Charles; splitting one line level output into two and feeding them into two sub inputs is fine, but two outputs into one input isn't. The signals on the two cables don't know that they're supposed to go only into the sub, so they also run up the other cable into the receiver, causing at least distortion.

I was hoping you'd chime in. So isn't there something that does outside the sub what happens inside?

Yes, there is a circuit that can safely sum two line level inputs into one. The problem and the circuit which can overcome it are described well in this Rane note . I'd think that somewhere in the vast land of audio someone offers those ready-made, but I've never looked.

Thanks for the input john!

Edit: BTW, you are way too smart with audio for your own good, how do you even come up with these sites???

They do. They're called cheap mixers:

geeze, now I feel like an idiot...