Buying a subwoofer... 2.1 setup on Ultralite... HOW?

[N8-R]

Hi there.

So I've decided to get a subwoofer to aid with my monitoring. Considering the Event S100 since it seems to suit my ALP5s. This sub gives me 2 options for connection:

1. Connect the main outs of Ultralite to the sub's unbalanced RCA input and connect the monitors to the sub's THRU unbalanced RCA jacks.

2. Keep the monitors connected directly to Ultralite with my current balanced TRS cables and use a third TRS to connect to the sub's mono 1/4" input.

Can anyone say which is the better option? If I went for option 2, how would I go about setting up Ultralite?

I'm guessing I'd need to connect my monitors to Analog 1-2 and the sub to Analog 3, 4, 5, or 6 and in MOTU Audio Setup set Main Outs volume to 5.1? I've tried searching tech notes on the MOTU site but cant find anything describing proper 2.1 or any other multi-speaker setup.

Any help?

[HCMarkus]

When mixing in stereo (which is what you will be doing - the sub is a mere extension of the satillite woofers) you typically want to feed a full-bandwidth mix from your audio interface's stereo outs. The full-bandwidth mix is then sent to a bass management device, which is often a subwoofer with internal crossover capabilities. Subwoofers offer a variety of levels of bass management flexibility, from none to flexible 5.1 bass management.

Two major tasks need to be accomplished in bass management: 1) splitting the audio band via a crossover network to feed the sub and the satillites appropriate frequency ranges. and 2) setting relative levels of the sub and satillites. Relative phase of the sub and satillites can also be managed at this level.

I took a look at the S100 info. It has a lo-pass filter that sends only bass 120hz and below to the subwoofer. It has a level control, which allows you to match the sub level to that of your satillites. It does not have a phase switch. It has pass thru jacks that pass the full-bandwidth stereo audio signal to satillites.

The downside of the setup is a possible low-frequncy boominess and/or phase cancellation due to all three drivers producing sound in the 80-100Hz range. The subwoofer crosses over at 120Hz. The Alp 5 reportedly produces output down to 53Hz, but does not appear to have a high-pass filter available. A more sophisticated system would cut lows under 120Hz to your satillites to allow a smooth transition to the sub without boominess. On the other hand, these products may itegrate really well in your listening environment. One can hope that they were designed to be compatible.

Hopefully, your chosen system will accomodate your needs. Placement of the sub can make a significant difference in the way the system sounds. I would recommend against feeeding the sub and satillites independently from your Ultralite, as complicating factors will conspire to make success unlikely.

[N8-R]

Thanks a lot!

After reading your reply, I totally agree. Seems like option 1 is the way to go.

About the crossover freq issue, I noticed the specifications dont mention any adjustment controls, which as you say, may generate some boominess and/or phase cancellation issues.

You say the pass thru connection feeds full-bandwidth signal to the satellites. Where did you read this?

I was sort of hoping that the pass thru connections would have some sort of HPF to adjust the signal going to the satellites in order to address the crossover issue.

Cant believe the folks at Event would overlook something as fundamental as this.

[HCMarkus]

It appears the Lo-Pass filter is set at 120Hz. No sub phase contol either. You could reverse the phase on your satellites with a little cable splicing, if necessary.

I surmise that "Pass-Through" means just that. Another clue: the presence of a footswitch jack to allow monitoring with and without the sub. If the pass through jacks had a High-Pass filter, the filter would have to be disabled when the footswitch was engaged or the satellite-only sound would be bass-deficient. If this kind of effort had been put in to the design, I expect Event would brag about it in promo materials.

Depending on the response of the satellites and the sub, room placement and acoustics, the bass overlap may not be a problem. Also, a lot of people like the "warm" sound they get when bass is overemphasized. If your mixes tend to be muddy, a little boost might not be a bad thing. Again, place the sub carefully! Moving the sub a foot or two in any direction could make a huge difference. Good luck!