Audio Interface with Crossover

I want to run a 6.1 speaker system.
I was wondering if any of the audio interfaces have built in high and low pass filters and the ability to split and sum signals so that I could program a subwoofer crossover.
I know that I can do this in Reaper, but I don't want to have to load another program every time I start my computer.

I understand you would rather have the crossover in the audio interface. That would definitely be advantageous, I agree. I don't know if there are interfaces out there that provide this.

That being said, I'd just like to push back and ask why you are against loading another program?

If you are concerned about Reapers CPU use, it is almost negligible. On my Hauptwerk computer with a 10-year-old CPU and only two cores (i5-3570k), reaper takes around 5% of CPU. That is with a 4.1 system, all five channels have the butterworth filter as high/lowpass. But most of that CPU use comes just from drawing the audio meters in the user interface! When I close the bottom mixer panel in Reaper, it is down to 1-2% of CPU use.

If you are concerned about latency, my subjective impression is that latency is a little bit higher with Reaper in the mix. But again, these are very small amounts of extra latency that are barely noticable, and do not affect the quality of my playing.

posted same thing twice

[mdyde]

Hello b_physics_guy,

I've merged your other identical topic into this one to keep the discussion in one place. If you wouldn't mind, please avoid 'cross-posting' duplicates in several places so that people don't end up replying unnecessarily in duplicate, or replying without being aware of others' existing replies -- many thanks.

You can get a crossover like this:

https://www.long-mcquade.com/11018/Pro- ... Output.htm

an equalizer like this:

https://www.long-mcquade.com/842/Pro_Au ... and_EQ.htm

Or a mixer like this:

https://www.long-mcquade.com/5793/Pro_A ... _Mixer.htm

that could all more or less do what you want, though the most appropriate would be the cross over. There are also probably more and less expensive options. All of these you would insert into the audio stream between your audio interface and the Sub. If you have an interface like a MOTU, then they also have software that allows some equalization (though their computer overhead would be similar to a DAW). That being said, some subs actually have built in filters as well.

But I agree you're wasting your money. The overhead of a DAW is pretty minimal unless your computer has very little RAM or a very old processor. Even then, it makes more sense to buy a better computer than one of these, because Hauptwerk is pretty computer intensive.

To do 6.1 I would need 3 hardware crossovers and something to add the sub signals back together.

If I got an interface with enough physical outputs, I could reroute the output of a low pass filter back into another physical input of the interface, then combine it with other signals to build up a crossover. I don't understand why there isn't a feature to route signals this way internally. I would pay extra for this if a top end model had it.

One of my biggest concerns with Reaper is having to reload it every time I do a Windows update.

Many audio interfaces have built in mixers, and Hauptwerk has a mixer, so a mixdown for a sub is routine and I'll bet most of us do it. Where did you find a sub without its own low pass filter so you have to create a crossover?

The MOTU and RME mixers have per channel equalizers to shelf the sub, and high pass filters for the main speakers, if needed. That DSP activity is done in the audio interface, no overhead on the computer at all.

MOTU audio interfaces have standard EQ plus a Shelf option on the High and Low filter bands. They also have separate High Pass filter.

For project I'm working on, we will be using these EQ features to drive 4 vintage Atltec-Lansing VOTT speakers who passive cross overs are all shot.

Danny B.

I have smaller monitors hanging from my ceiling so I'd like to have different crossover frequencies. If I used the same frequency for each stereo pair, all I would need is high and low pass filters, which I assume any interface has. The hard part is adding the 3 subwoofer signals back together. I couldn't figure out how to do this on a Motu Ultralite I had years ago and a guy from Sweetwater recently told me that none of the interfaces can be used as a crossover.

It would be nice to hear from someone with a specific setup that works.

Oh. I take the differing ranges of speakers into account by which ranks I route to the groups with speakers with less bottom, so I've never needed to vary the sub crossover range. The little speakers that give up at 60 Hz only get half length 8' reeds, 4' stops, and upperwork, so they don't need the sub. The sub only has to reinforce the bottom pitches for the bigger speakers playing 16 and 32' stops, so the sub's filter is sufficient. The bigger speakers have low ranges close enough to each other.

In my opinion, the best way to do 6.1 audio is to get an interface with 8 channels. 6 of the channels have their own monitor, and the last 2 carry the sub mix-down from Hauptwerk (which it can produce automatically from the other 6 channels). If your sub doesn't have its own crossover, then you would only need one.

I'm not sure why the monitors all need to have a different cross over frequency, or indeed, why they need to be filtered at all. Most of those who have posted who use smaller monitors just feed the whole signal to the monitors. Usually the low frequency components don't cause a problem. If you're getting rattling or some such, then it makes sense to feed the 6 signals into a mixer where each channel has low, medium and high, and go about it that way. However, I would think it makes more sense to secure the monitors to a sturdy bracket or mount them in a location where they don't cause a problem.

In my opinion, the best way to do 6.1 audio is to get an interface with 8 channels. 6 of the channels have their own monitor, and the last 2 carry the sub mix-down from Hauptwerk (which it can produce automatically from the other 6 channels). If your sub doesn't have its own crossover, then you would only need one.

So it would look like this:

A) 6 channels from HW to interface - use interface for 80 and 60Hz high pass filters - output to 2 'oberwerk' ceiling monitors and 4 'other' monitors
B) Mono channel from all HW 'oberwerk' stops - Low pass filter around 80Hz - send to right channel input of my subwoofer
C) Mono channel from all other stops - Low pass filter around 60Hz - send to left channel input of my subwoofer.

I forgot that my subwoofer had left and right inputs. I don't see any reason why that couldn't be used for two mono signals. I think this works.