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Hi guys,

What's the best way to get a subwoofer output from my mixer?

The only low-pass filter references in the user's manual are related to the effects.Would I be better off using one of these effects with all the parameters BUT the LPF zeroed out, or would it be better to use an Aux Mix with EQ applied?

Of course, I'd want to apply a high-pass filter on the mains, too. That seems a bit more straightforward.

Please explain it like I'm 5 years old. Okay, maybe not 5; how about 15?

Thanks a million!

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by wahlerstudios on Fri May 17, 2019 5:25 am
The Series III mixers have a physical Mono output, but it's only the new StudioLive 64S which is really using it (LCR, LPF). For all other SL consoles it's just a summed signal of PA left/right, which is muscially more or less useless. The Low Pass Filters in the FX machines are there to "shape" the sound of a particular effect, not the general sound or controlling subwoofers. The FX machines anyway have no physical output, unless you route/send them to a fixed subgroup or a flex mix.

There are simply no Low Pass Filters available on the 32-channel Series III mixers and the rack mixers. Already for some years, being able to use LPFs and HPFs on the inputs and outputs has been one of the highest voted feature requests, which the PreSonus engineers study thoroughly every day, as we all know.

You are not describing which kind of subwoofer or subwoofer system you are using. Mono subs are an option, but not a must. Do the subwoofer/s see the whole music program, just reduced in freqency range, or do you want to send selected instruments to the subwoofers? In this case "Aux Subs" are a good concept. Link two auxes (9+10 for example, the last two on your SL16), rise the faders (kick, toms, bass, tuba, alpine horn...) and the aux master and - in the aux master - adjust the parametric equalizer to your taste. Depending on the loudspeaker/s you are using, sometimes it doesn't need a lot of frequency manipulation. If the speaker range ends at 400 Hz, it can not transmit higher frequencies, hence you don't need to "eliminate" higher frequencies.

You can also route two of the graphic equalizers to aux 9+10 for frequency adjustments. Together with the 6-band parametric equalizer there should be enough possibilities to manipulate the sound of your subwoofer/s. This is not the professional way of dealing with this subject, but it works... Always better is a active external x-over or controller.

SL16 | 32R | 16R | 3* 16M | SW5E

Apple routers | iPads | Alesis iO Docks | Yamaha S112, S15e, S10e, SM12, SM10 | LD Systems Curv 500 | Galaxy Audio Hot Spots | Mac mini | Lenovo Laptop | Studio One Artist 5.1.2 & Pro 3.5.6
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by bradwaite on Fri May 17, 2019 8:56 am
Thanks for the response, Hans-Martin.

Based on the manual and forum, I wasn't expecting a separate mono output with a true LPF on my older SL16.

And of course, the FX weren't designed as LPFs, but I was thinking of them as a workaround, routed as you mention, to a flex mix.

This is a smaller church auditorium (250-seat) with a single JBL CBT70J main speaker and JBL SRX828S passive sub, both mono. I was expecting to send the whole program below ~80Hz to the sub. And while sending the full-range audio to the sub would work, it's by no means ideal for the sub, the mains, the amps, or the listeners.

Yes, an outboard crossover is ideal, and is what we're using right now. But I'd like to see how well it works using the mixer.

I'm not sitting in front of it right now, and the routing/Fat Channel adjustments would probably be more obvious if I were.

I'll report back after I've had a chance to toy with it, but if anyone has any other suggestions, I'm all ears.
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by wahlerstudios on Fri May 17, 2019 9:20 am
Interesting... Who has recommended using these loudspeakers? This combination does not fit together at all! Honestly, I would say, forget this mono bass thing. Do something on your PA. 250 pax is not much. My two aged S112IV would easily make that job, even with a full band.

Just my 2 Euro cents.


SL16 | 32R | 16R | 3* 16M | SW5E

Apple routers | iPads | Alesis iO Docks | Yamaha S112, S15e, S10e, SM12, SM10 | LD Systems Curv 500 | Galaxy Audio Hot Spots | Mac mini | Lenovo Laptop | Studio One Artist 5.1.2 & Pro 3.5.6
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by bradwaite on Fri May 17, 2019 3:41 pm
Why don't you feel that these speakers work well together?

And why forget the mono bass thing? Bass is omni-directional to human ears, so other than filling in for room modes, I don't see the advantage of multiple subs.
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by wahlerstudios on Fri May 17, 2019 4:15 pm
The JBL CBT70J "Column Speaker" belongs to the wall-mountable series of loudspeakers for fixed installations, which is used primarily for spoken word. It has 16x 1" speakers and 4x 5" speakers. There is no bass cabinet available in this series. If there was one, it would probably be a 10" speaker.

The JBL SRX828S is a 2x 18" subwoofer, which is completed by a JBL SRX815 (15" speaker + 1.5" horn) or a JBL SRX835P (15" + 6" speaker and 1.5" horn). There is also a JBL SRX812 (12" + 1.5"), which can be used as monitor, front or satellite system. Together with a JBL SRX818S (1x 18") this is the "JBL SRX800 Passive Series of PA loudspeakers for touring".

The SRX speakers were built for live music and they are much more powerful than anything which is "wall-mountable". If you would add one or two JBL SRX812P to your subwoofer, you would hear the difference right away. You need to use the same type / family of speakers. It makes no sense to look for a solution for your bass system while the top speaker is the problem...

SL16 | 32R | 16R | 3* 16M | SW5E

Apple routers | iPads | Alesis iO Docks | Yamaha S112, S15e, S10e, SM12, SM10 | LD Systems Curv 500 | Galaxy Audio Hot Spots | Mac mini | Lenovo Laptop | Studio One Artist 5.1.2 & Pro 3.5.6
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by sjc193 on Mon May 20, 2019 7:30 am
I can chime in here. I am the paid sound guy and a musician for a church in my home town. They had a Bose L1 setup that I had sounding perfectly fine. We have a 5-7 piece full contemporary band in there every Wednesday and Sunday. We have a 16.4.2AI and I mix with the iPad. Truly I tell you that I'm the only one who knows how to use the mixer properly.

The church leaders decided that they wanted to buy new speakers for the church and send the Bose to their sister church the next town away. Guess what! No one asked my opinion! You know who they did ask? Sweetwater sales engineers! Ugh! So of course the Sweetwater guys said "you gotta buy these great (over 1000 dollars a piece) speakers because they are so great for churches (CBT70J). They're going to get rid of all of the reflections and all you are going to have is great sound only where the people sit and you're going to be so happy!" The church leaders bought them and had them installed with no input from me whatsoever and one day I came in and there they were, I had to rush around trying to get a decent sound out of them before church started in 30 minutes. Feedback was a big issue at first trying to get these things loud enough, I hear tons more reflections and reverb than I used too. It took me a few weeks to get anything decent out of them at all. I did force the church to have the install guys come back in because they were installed stupidly (pointing the wrong directions), so they fixed that, but I'm really still not happy with them, they just suck for live music that's all there is to it, there is no low mids to those things at all. We have a JBL15 active sub used with them, but there is a big hole between the sub and the CBT70J.

So, here's the thing, I will have to use these speakers for probably many years and I'm guessing you are in the same boat. Sometimes you do not have the luxury of just saying, Oh! you just spent $4,000 (speaks and xti2002 amp and install), but let's spend more because you bought the wrong thing. Do you think my bosses want me to tell them they bought the wrong thing? Nope! "I mean, the Sweetwater guys said these are the right speakers for us, how could they be wrong?". . . They just expect me to make it sound great and for everyone to be happy because everything is perfect, because they pay me to make it perfect. Ugh.

Sorry, clearly this thread has brought up some issues for me. . .lol. . . I'm really mad no one at the church asked my opinion about this major purchase :evil: . . .

To answer the question, use your active crossover that you are already using, that's the way to go. Feel free to bring it up to at least 120hz maybe 150 . . . or 200. . . Also, I found that I needed to bring the little gain knob on the back of the 16.4.2AI up quite high to get any get up and go out of the speakers. Also make sure the little knobs on the side of the speakers are set right (music not speech, the right vertical degrees you need)


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