Adding a small Subwoofer

[Boombastix]

I was thinking of adding a small subwoofer (using parts I already have).

I have several outputs from my audio interface, what if I use output 3-4 for the sub, going straight into a standard amplifier (no crossover filter), that feeds the sub.
Inside Reason I split the Master Out so it feeds my 1-2 Audio Output as normal (small monitors), but also feeds output 3-4 via a LP filter for the sub. Set the filter to 50-60Hz sort of.

Any issues with that, that comes to mind?

[Sterioevo]

A seperate level control is useful - I normally do with my sound card.
I would use a the stereo imager to mono the sub signal and work around the 100-150Hz range.

[demt]

the behringer ddm dj 4to 8 track mixer has specific outputs for the sub decent mixer cheap 2 loadsa effecrts

[Boombastix]

I have the Elements Splitter on my master channel to do sub stereo to mono. Set at 83Hz. Volume knob is on the HW amplifier, it is just missing the filter.

I guess the kHs filter set to around 60Hz for output 3-4 will do the trick. Adding a volume/gain knob before the kHs filter is not a bad idea as I then can adjust the sub level while sitting in my sweet spot, rather than walking over to the amp. Probably good to have that gain knob handy when someone complains about the sub level from an adjacent room or whatever

I'll update my template and try this out. Thanks for input!

[Skimrok]

the behringer ddm dj 4to 8 track mixer has specific outputs for the sub decent mixer cheap 2 loadsa effecrts

looking at your signature I picked up that dj mixer around 2 years ago when I was on a mission to get myself some media decks to try out, basically it was part of a package from a guy which was leaving the country, I ended up selling the media decks because the numark decks wouldn't play Wav files on the usb slot but I kept that mixer just in case it comes in handy down the line because I think I'm always going to have dj gear like turntables and mixers around me till I kick the bucket, I've been like that since the late 80s, I didn't even look at the back with the dedicated sub output, so reading your post I thought that's cool to know,

[demt]

the behringer ddm dj 4to 8 track mixer has specific outputs for the sub decent mixer cheap 2 loadsa effecrts

looking at your signature I picked up that dj mixer around 2 years ago when I was on a mission to get myself some media decks to try out, basically it was part of a package from a guy which was leaving the country, I ended up selling the media decks because the numark decks wouldn't play Wav files on the usb slot but I kept that mixer just in case it comes in handy down the line because I think I'm always going to have dj gear like turntables and mixers around me till I kick the bucket, I've been like that since the late 80s, I didn't even look at the back with the dedicated sub output, so reading your post I thought that's cool to know,

thanks for ther ups its a great mixer and really pumps out a heavy bass on eatch channel ,ive allso got a 100w subwoofer with adjustable crossover to do it justice.

[selig]

For me, the biggest factor is how well the sub integrates with the rest of the system, something that is not that common in my experience. Most of the time you just end up with a separate "butt thumper" type effect rather than a smooth extension of the frequency response. There are a lot of factors involved in this, and I long ago decided to only use a sub that was specifically designed for my main monitors (and am super happy with the results).
Even with such a well integrated system, you'll still spend time with placement, polarity, and any other settings your system allows - you just won't have to worry about finding the perfect crossover frequency as that's already been done for you.
Since this is a DIY project I'd strongly suggest having a test mic and software on hand (plenty of free options these days). I have the Behringer ECM8000 which was the best $50 I ever spent!
From there you have to figure out how you will export your mixes (since the spectrum is now split between outputs, how you will adjust playback volume, how you will connect headphones, etc. since none of these things will be straight forward.
That's the advantage of a system where you feed the main stereo outputs of your system first into the sub then onto the main monitors. Not only can you control everything from one place (monitor volume, headphones, input selection, mono, dim, etc), you can also easily switch to alternate monitors and calibrate the levels of each so they match.
I'm using the Persons Central Station for this and it's working great for years now.

For your specific setup I'd create a Combinator for all routing and control. You'll also want to add a master volume control so the sub and monitor track volume changes equally, as well as a separate level control to trim the sub level. Ideally you'd want to have the main signal from the Reason mixer fed directly to the Hardware Interface inputs 1/2 and then use a splitter on that signal to get a separate signal for the monitors. This is assuming you have enough hardware outputs to have an additional stereo output for the mains and mono output for the sub. This way you can have a volume control for the monitor system that doesn't affect mix bounce levels, which is pretty important. Otherwise you'll have to reset the level for bounces, which may be painfully loud for monitoring (or may not, depends on how you gain your setup). Next I'd add a complimentary crossover for the main monitors so you don't double up on any frequencies. The Stereo Imager is ideal for this since you can use it to split the signal to the mains and sub, plus create the mono signal for the sub. I'd mono the sub since you won't need to output two channels into the sub (unless you have two channels of amplification and the hardware to convert the stereo signal to mono). That way you can run the amp in mono mode if possible to get even more power - subs are power hungry! You can then add a dim and mono button for the entire signal, as well as a Sub Mute (that disables the main crossover as well) and separate L/R speaker mutes. This would give you a killer setup equal to what I have with the Central Station minus the input selector and talkback section.
Happy to provide more details if you take this route!

[Boombastix]

Thanks Selig. Yeah, maybe better to split/filter outside of the DAW. Need to test a little. Rump Shakers can be useful though, if that is what you user/audience is using. But my plan is just to add a little extra sub extension.

I do have the ARC system from IK Multimedia, so I can sweep the room.

[demt]

keeping the main speasker volume pot handy makes it a breeze to adjust when needed

[Boombastix]

There is a volume knob on the old amp, just not a LP filter, so I can balance the setup. But my audio interface volume knob only affects outputs 1-2, so I think a cheap external passive hw filter is easiest actually. They're only like $20.

[demt]

There is a volume knob on the old amp, just not a LP filter, so I can balance the setup. But my audio interface volume knob only affects outputs 1-2, so I think a cheap external passive hw filter is easiest actually. They're only like $20.

cool