USB Audio Question thats been bugging me for ages !

Hi all,

Im new here, Apologies if this is in the wrong section.

I am in good knowledge of musical equipment as i DJ and Produce but this has been eating away at me for ages.

Basically, I bought some USB alesis 520 usb monitors which, are good, i am happy with them. They have an integrated USB Interface inside one of the speakers.

The question im asking is, Although these go down to about 45hz, IF i wanted to add a subwoofer to this setup, How would i go about it. I cant get the signal path in my head.

Of course, these speakers, Being usb makes it either, Impossible or all the more difficult.

The way its setup at the minute in my room/Studio is … PC to Monitors Via USB cable Which uses USB Audio codec …1/4" jacks from back of my Monitors to my DJ Mixers Tape (RCA/Phono) (to record my DJ sets into computer, Through speakers) … All works fine, I just wished some how i could add a sub to my Monitors to get extra low end in my mix downs. Maybe a USB Subwoofer Perhaps, But would this work along side my monitors or conflict ?

sorry about the long post but thanks in advance !

The Alesis 520 usb monitors are designed to be used without a sub.

Although it may be nice to hear that real-low-down bass, when mixing it can be almost as much a disadvantage as an advantage.
When mixing tracks for a CD, the “target audience” for the finished “product” will probably not have real-low-down bass, so if you mix only on a system that goes way down low, then you will be hearing stuff that most of your audience will not hear, so often it is better to mix on good quality speakers that have a reasonable, but not extreme frequency response. The ideal would be to have both - a system with real-low-bass, and a system with an accurate response over a more modest frequency range.

Another problem with adding a sub is that the frequency response at the cross-over frequency is likely to be unpredictable. Depending on the phase relationship of the sound from the main speakers and the sound from the sub, the crossover frequency band could be either weakened or exaggerated, or worse still, weakened at some frequencies and exaggerated at others. This can be disastrous when mixing as you end up Eq’ing the bass end to sound right on your system, but sounding wrong on every other system.

So that’s the dire warnings out of the way - no for how to do it :wink:

The Alesis 520 usb monitors have a pair of 1/4” TRS inputs on the back. These can be used as a line level input instead of the USB input.
The simplest way to set up these speakers with a sub would be to use a Line level output from a sound card to send the audio to an “Active Sub”. Many active subs have built in cross-overs with a left/right pair of line level outputs. These outputs could then be connected to the 1/4” TRS inputs on the back of the Alesis 520 usb monitors. Assuming that the cross-over has an adjustable cross-over frequency, this should be adjusted to give the most “flat” response from the system.

Another options would be to put the Alesis 520’s closer to a wall as this will tend to raise the bass response a little.

finally a clear Answer, I appreciate that mate. Its not dier, Getting a sub… And i do understand what you mean about OVER EQ’ing, As i used to do it when i was first learning to produce using a Hi fi system which was Massive in power. I tended to get it sounding mint on that system, Then id take it to a car, and it would be awful, Too much bass and sharp in the hi freq band.

These speakers definately improved my mix downs before taking it to my mates studio. Everything sounded bang on apart from the slight lack of penetrating bassline which is usually apparent in my tunes (DNB, UK-G, Dubstep).

But i suppose ill deal without it and get to learn how my speakers cone reacts to certain levels of bass.

These speakers arent bad by any means on the low end, there pretty decent in fact, I just had this question rolling around for ages and needed answers… With regards to hooking them up to a sub IF I WAS going to do it… that just seems very, Contradictory to buying usb speakers with a sound card in in the first place. Just more added cost.

So i think ill leave it lol…Thanks mate !