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Trying to use my Active sub with active monitors

Member for

1 year 4 months
Hi all,
My power amp has blown, so I'll be getting some near gear, and was hoping to be able to use my sub in my new setup.
At the moment, it's
Audio interface (Which needs to be replaced as not working with Windows 10) ---> Power amp ----> Subwoofer (PSB Image subsonic 6) -> Tannoy reaveals PASSIVE monitors.

So I'm going to be changing the audio interface to most likely
Focusrite Scarlett 18i20 3rd Gen
(Connections are more or less the same as current interface so no big deal here.)
The power amp and passive monitors will be replaced by active monitors (most likely KRK RP7's).

So ideally I want to connect like this: Audio Interface ----> Sub > Active monitors.
Do you think this is possible?
The problem is the active monitors take a TRS or XLR connection.
The ins and out on the sub are speaker cables (either raw wire or banana plugs). There are also RCA connections.
I will attach a picture of the subwoofer connections.

Is there anyway I ca do this, or would I have to get a different sub?
Would buying a different audio interface with a Subwoofer out connection be an option in my setup?
Thanks in advance.
Attached files

Comments

Member for

15 years 7 months

Boswell Tue, 07/28/2020 - 09:35
Hi, and welcome!

I would not advise doing the main/sub crossover in the audio interface. You need to present a full-range powered speaker to the line outputs of an audio interface or other line-level source. That implies that you should choose a sub that has balanced line-level inputs and high/mid balanced outputs for feeding powered full range loudspeakers.

I have never knowingly used PSB speakers, but they look to be reasonable performers. The Image 6 that you have appears to be squarely aimed at the consumer market, and will take loudspeaker-level input signals and pot these down to domestic-level audio to feed its internal power amp. You can also go in directly to the unbalanced domestic-level RCA sockets. All-in-all, not a good match for a pro audio interface.

You could fudge things to make it work, but it would be at the expense of sound quality along with the likelihood of introducing hum and noise. My advice would be to get your new full-range powered speakers plus a new sub that has balanced inputs and also has a bypass switch. Wiring to those is simple: TRS jack or XLR leads from your interface outputs to the sub inputs, then the same again to the balanced inputs of your mid/high speakers. Connect a footswitch to the sub's by-pass control input, and you are good to go.

If you want to continue to use the passive Reveals, then you would need to connect a simple pro-level audio power amp between the sub's outputs and the Reveal inputs. There are many of these to choose from, but it's a dead-end route to take.

I have a KRK 10S subwoofer and KRK V6 mains, and they work well. In my usage, I find the by-pass switch is essential when checking mixes.

Member for

15 years 7 months

Boswell Tue, 07/28/2020 - 15:09
Enough power for a small-medium studio for normal types if music. When I was topping and tailing the St Magnus Cathedral organ recording I made, I had to reduce the overall listening level because the sub could not handle some of the pedal notes (at about 110dBA !). I posted a very short extract from this recording in another thread recently.

Member for

8 years 9 months

pcrecord Tue, 07/28/2020 - 16:30
KRK with the KRK sub sounds like a good idea.
In my case I chose the Yamaha HS8 and HS8S. I find them well balanced for my room..
If you are in a small room too much power could be a problem.. you see you need to crank the speakers a bit to get the membranes moving..
If the speakers are too loud and you need to run them at low level they will barely move and won't project their full blown register..

Member for

7 years 9 months

paulears Fri, 07/31/2020 - 04:13
I've never done it yet, but with my live audio, it's now common to feed subs via a proper desk output for real control, and I wonder why we don't use the spare outputs for the same thing? The control room facilities in software now allow all kinds of processing and tweaking so next time I need subs in the studio, I'm going to wire everything to the interface and sit back to adjust!

Member for

15 years 7 months

Boswell Fri, 07/31/2020 - 05:30
paulears, post: 465090, member: 47782 wrote: I've never done it yet, but with my live audio, it's now common to feed subs via a proper desk output for real control, and I wonder why we don't use the spare outputs for the same thing? The control room facilities in software now allow all kinds of processing and tweaking so next time I need subs in the studio, I'm going to wire everything to the interface and sit back to adjust!
I haven't seen a mixing desk that has crossover networks with Linkwitz-Riley phase responses. These are needed for the crossover transition between sub and mid-range to have any hope of maintaining a flat amplitude characteristic through this range. The EQ circuits in mixing desks do not in general work for loudspeaker crossovers.

I've frequently used aux-fed subs in PA work, where the spread of sub-to-main matching can vary hugely over the large listening area, but I would not use that technique for studio mixing or for mastering.

The mid/high outputs from the networks inside subwoofers do have L-R characteristics, at least the ones from the reputable makers.

Member for

8 years 9 months

pcrecord Fri, 07/31/2020 - 05:48
Boswell, post: 465091, member: 29034 wrote: The EQ circuits in mixing desks do not in general work for loudspeaker crossovers.
I worked on different live venues that did use the a Yamaha M7CL. This one is geared to seperate the subs. On each channel you get to decide if the signal goes to the subs and you get a main sub fader..

But as you say this is an exception, mixers aren't usually geared to do crossover work... That's why big PA so often comes with dedicated crossovers when you rent them.

Back to studio monitors, the Yamaha HS8S got a crossover included and also have stereo input and outputs.

Member for

15 years 7 months

Boswell Fri, 07/31/2020 - 07:41
Yes, the X-32 and M-32 have the L-R filter as a selectable option in their Matrix sections. However, the specifications do not say whether these are implemented as IIR processes in order to emulate the phase response of equivalent analogue filters. If they are done as FIR (linear-phase), then they are no better than the other selectable filter types, and will have a half-length time delay. The time delay need not be a problem when mixing off-line (c.f. DAW latency compensation), but can give trouble in live work.

Here's a good article about IIR vs. FIR filtering in audio applications, but it makes light of the half-length time delay of FIR, which can be a very real concern.

Member for

7 years 9 months

paulears Fri, 07/31/2020 - 07:45
No idea to be honest - but they seem to work OK on my line array and traditional PA setups. I'm never totally convinced about adding subs in the studio. Mine doesn't have them at all, just older, bigger normal monitors. I know you should not be able to localise bass, and in live work a misbehaving extra loud sub can only be found by getting close to it, but I'm convinced the cutoff point where the main driver is replaced by the sub in a different place is audible?

Member for

15 years 7 months

Boswell Fri, 07/31/2020 - 09:01
paulears, post: 465096, member: 47782 wrote: ...but I'm convinced the cutoff point where the main driver is replaced by the sub in a different place is audible?
Ha, yes, that raises a different can of worms. Phase linearity through the crossover frequency can only work if the loudspeakers are installed correctly (relative to the vertical plane), and that the listeners are located in an area where the acoustic wave summation from the different driver units is coherent.

Even the positioning of a subwoofer in a mixing studio can be difficult. Most room analyser programs get you to flatten out the amplitude and don't pay much attention to phase linearity.

Member for

12 years 4 months

kmetal Fri, 07/31/2020 - 11:46
Subs in a studio can increase headroom/lower distortion by lightening the burden on the main speakers and amplifiers. I think many 2 way designs ask quite a lot from the mid/woofer and amp channel. Covering roughly 40hz to 1.5khz is a pretty tall order for a 6 or 8" speaker and amp channel, in a fairly small enclosure.

Member for

12 years 4 months

kmetal Fri, 07/31/2020 - 13:32
paulears, post: 465099, member: 47782 wrote: Yes - which is why I find it weird studio monitors have got smaller and smaller, when it's easier to use bigger ones, and frankly, all the small speakers sound far less good when you play them loud.

Probably because studios have gotten smaller, ie bedroom sized.

Maybe dedicated sub use has contributed to smaller mains??

My life changed when i started to use soffit mounted mains, urie 813c's. Mixing sound "life size" made panning a much more relavant tool. Those are considered old and not accurate by today's standards, but the room was designed for them (80s lede).

The cost of current studio monitor mains puts them out of reach. 20k and up from what ive seen. You can get a set of passive jbl or qsc full size theater speakers for 6-8k. Ive considered doing this in my next studio.

Member for

7 years 9 months

paulears Fri, 07/31/2020 - 14:15
There were loads of decent studio monitors - 1-" through to 15" and I really liked the sound, then we all had to have a pair of near fields too, so we're all mixing on clever small speakers designed to sound like bigger ones with cleverness. The simpler larger types are still sought after - look how much they go for on ebay - but nobody makes them any more. Even the hifi brigade are doing the same thing - whacking great boxes with 5 or 6" drivers.

Member for

12 years 4 months

kmetal Fri, 07/31/2020 - 15:03
paulears, post: 465103, member: 47782 wrote: There were loads of decent studio monitors - 1-" through to 15" and I really liked the sound, then we all had to have a pair of near fields too, so we're all mixing on clever small speakers designed to sound like bigger ones with cleverness. The simpler larger types are still sought after - look how much they go for on ebay - but nobody makes them any more. Even the hifi brigade are doing the same thing - whacking great boxes with 5 or 6" drivers.

Thats interesting i didn't realize even hifi was moving to smaller footprints.
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