Questions about the QU-24 from a newbie

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This topic contains 11 replies, has 5 voices, and was last updated by Profile photo of guyburns guyburns 4 years, 6 months ago.

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    Profile photo of guyburns

    The local theatre, which I am hiring for several performances in November 2019, has a 24-channel mixer. For a recent sound check I was told: “Just go into the sound booth, everything will be turned on, and away you go.” Well, away I didn’t go. So I noted the model (Qu-24), and here I am. I have downloaded the Reference PDF, read it once, and am now going through it a second time making detailed notes.

    I have several questions, but my first is…

    Ques 1
    I am looking for a high resolution image of the QU-24 front panel so that while I am studying the Reference PDF, I can jump into Photoshop and study the actual layout. The front-panel images in the three PDFs I downloaded from Allen and Heath are poor quality, and Google was of no use because they have recently removed the ability to select the resolution of the images.

    So, does anyone have a high-quality image of the front panel of a QU-24? Or a link to an image? High-quality meaning that I can clearly read every bit of text on the front panel.

    You can gmail me at gdburns.

    Profile photo of Mike C
    Mike C

    Just open a front surface image on the QU24 section on the A&H website, do a right click on the image and select save as. You can then zoom it up enough to see most details.

    If you have an iPad download the QU Pad app and run it in the demo mode, that would give a feel for the mixer, actually I think the menus are easier to get around on using the iPad than the surface.

    Is their mixer on a wifi network, if so connect to it and control the mixer remotely.

    Profile photo of guyburns

    Thanks for the suggestion. The photos on the website, about 1800 x 1300, are better than the PDF images, but the small print is still difficult to read. If anyone knows of a front panel photo of 3000 x 2000 or higher, please let me know.

    I don’t have an iPad or access to the mixer unless I book the theatre, so I want to learn as much as I can in theory and make extensive notes so that when I next have access, I am confident I can get the thing to function as I want.

    I have a very simple use for this mixer. Two line inputs from a Blu-ray player via 6.5mm jacks, and one mic input (Shure SM12A) via XLR. I want it to operate as a simple mixer, with no effects or processing of any kind. Questions about that will come later.

    Now for questions 2-3.

    Ques 2 — PAFL
    The first mention of PAFL in the manual (P22) says: “Press to listen to a channel using headphones and check its level on the main meters.”
    Even I can understand that. However, no mention of what PAFL stands for anywhere in the manual.

    Ques 2: Is PAFL: Pre and After Fade Listen?

    Further down p22 the PAFL options are explained:

    Output AFL – This option sets the mix strip PAFL keys to monitor AFL (afterfade
    listen). With this option turned off these keys monitor PFL (pre-fade
    listen). The default is AFL so that you can check mixes after the master fader.

    Input AFL – This option sets the input strip PAFL keys to monitor AFL (afterfade
    listen). With this option turned off these keys monitor PFL (pre-fade
    listen). PFL is the usual setting for inputs so that you can check and set their
    gain before you bring up the faders.

    On my photo of the mixer, there is only one strip of PAFL keys, yet the above implies there are two: “mix strip PAFL keys” and “input strip PAFL keys” Apart from that, the explanation is utterly confusing. There are two options, yet the explanations are identical. The only difference is in the default settings.

    Ques 3
    What is the difference between the Output AFL option and the Input AFL option, and what do they do?

    Profile photo of SteffenR

    watch the Video, it helps a lot at the beginning

    Strip means in this context the combination of Mute, Select, PAFL and Fader to control one signal (Strip)

    Profile photo of Mike C
    Mike C

    I’m guessing that for what you are going to be doing the PAFL on each channel would be the ones you would use the most to check the DVD or mic before bringing it up in the system.

    The biggest unknown will be how the mixer is actually configured and left from the last person who used it!!!
    From what you said that they told you “Just go into the sound booth, everything will be turned on, and away you go.” it sounds like they just let everyone go into the soundbooth and do what they want.
    I’ve seen the results of that and sometimes it’s kind of ugly!

    Profile photo of guyburns

    Thanks for the comments. I’m not sure how the sound booth is run. It could be as Mike surmised, that anyone can do as they want. There is an off-site theatre technician, and maybe he has put some controls in place. I shall find out.

    I have already looked at several videos, including the one mentioned, and am working my way through the manual for a second time. I’m the rare person who actually reads manuals in detail, and then asks questions. Q2 and Q3 remain unanswered, but I’ll move on to my next questions.

    Ques 4
    I was able to get the Blu-ray audio to work, coming in on Channels 1 and 2 via 6.5mm plugs, by switching off Mute. But no matter into which channel I plugged my Shure SM12A (tested at home beforehand), there was no sound. What is the most likely explanation for that? That the mixer was set to Basic mode with only channels 1 & 2 available?

    Ques 5
    Will a channel accept both Mic and line inputs at the same time? Or does one cut out the other? It is not clear from the signal flow diagram or the manual, how the inputs operate if both sources are connected.

    Profile photo of Mike C
    Mike C

    Q2 PFL mode picks up the signal before the channel fader so you can listen and meter it with out turning that channel up into the system.
    AFL mode picks up the signal after the fader, any level changes with the fader will be heard on headphones and seen on the meter.
    For input channel monitoring PFL is what is used 99% of the time.
    In the set up menu under audio, PAFL you want to select input AFL to off.

    Q3 That is what changes the mode that the PAFL button operates in, the input channels are set independent of the mix output PAFL.

    Q4 So the DVD workes when plugged into either Ch1 or Ch2, that means those channels are at least routed to the main mix outs.
    Are you plugging the headset directly into the channel XLR inputs or is on a wireless system.
    You said it worked at home, assuming you are not using a wireless system and going direct from the mics XLR connector to a mic input, try the mic plugged direct to the mic input without any other mic cable.
    Your headset mic does not need phantom power, so we don’t need to worry about that.
    The mic channel input gain may be turned all the way down, since the DVD is line level input source it does not need nearly as much gain as a mic does.

    When you said the mic working at home what did you plug it into?

    Q5 you should only use one or the other, not both together on the same channel.

    Profile photo of guyburns

    Thanks for the feedback. I’m trying to understand certain concepts and the way the mixer operates before I use it again, so there’s no need for detailed hook up instructions, if you know what I mean. It’s the concepts I’m trying to get a handle on.

    I should have explained I’m not a newbie when it comes to mixing or recording, just new to this device. I started playing around at home with double tracking on a stereo reel-to-reel when I was a lad in the late sixties, then in the 80s and 90s I had several 4-track Tascam cassette decks for home recording. Now I’m right into Adobe Audition for generating soundtracks for my Blu-rays. But I’m a complete newbie when it comes to an expensive professional mixer.

    Re the mic connection: no wireless connection, all direct. I tested the Shure mic at home, by connecting via XLR to my Focusrite Scarlett 2i2, and feeding into Audition via USB. I also checked my backup mic the same way.

    A final set of questions.

    Ques 6
    The situation is this: an announcer on stage with a mic introduces the show, then I start the Blu-ray whose audio is just the way I want it. The Qu-24 has all sorts of EQs, effects and processors on offer, but I’m pretty sure that none of them should be applied. That’s the right approach, isn’t it?

    Ques 7
    I may reset the mix settings when I am next at the mixer. On page 83 of the manual, under Reset Mix Settings, it states: “default reverbs and delay are patched ready for you to hear the effects as soon as you raise a channel send.”

    The defaults are listed as EMT250, Hall480, Delay, ADT. All EQ is switched in and set flat.

    Assuming that I want no processing of any kind on my audio (I’ll be guided by responses in this thread), is that what is going to happen if I reset the mix settings? It’s the phrase “raise a channel send” that concerns me. If I don’t do anything other than reset, will my audio remain unprocessed?

    Profile photo of volounteer


    I had the same problems. I took my own pictures of the entire front along with others of key sections so I could see what the manual was talking about. You really wont be able to read everything (at least I couldnt) without the close ups of the key sections, but the overall picture was still useful even if I cant read the fine print on it.

    PAFL is AH own terminology to combine pre fade listen and after fade listen into one acronym.

    The documentation is misleading. There are two buttons to the left at the top. But you also have to press select for the layer/channel that you want to hear not the one button on channel one like the manual misleading indicates.

    If you are in basic mode then you have my sympathy. And yes many things can be restricted so you cant use/do them.

    For layer 2 channels the block diagram shows you can put both line and mike into the channel and they are in parallel.
    Line levels may be too high to hear the mike though if you use both.
    For stereo channels it shows that a single mono omike on L side will go to both sides of the stereo if the other side has nothing plugged in. Or you can use L&R mikes for true stereo.

    Probably. Depends on the room and other factors whether you would need EQ or other tweaks to avoid problems.

    If you are in Basic mode you cant really change anything. You can reset to what they decided was what they wanted. From the manual:
    Basic – Faders and mutes only. This is for very simple level control. Admin can set access to none or a range of scenes for recall only.
    You might want to talk to them to give you a scene that handles what you do better.

    Profile photo of garyh

    The top face image on the A&H site for the QU-24 is 2800 x 1867. Select the picture, do a zoom in then right click and save the zoomed image. You can read the lettering.

    Profile photo of Mike C
    Mike C

    For your event, playback music and an MC announce mic
    you do not need to worry about effects other than that they are turned off.
    If you can gain access to the controls start with the channel EQ flat and apply
    the high pass filter to the headset mic, start at 80hz at least.

    Double check that the mic is working and has a full strong output. Those mics have
    a full size XLR connector on a very small cable, if either the connection on pin 2 or 3
    is broken you will still get sound only very weak and thin sounding.

    As for the PAFL, PFL, AFL…..some boards call it CUE, SOLO and within a set up menu you
    tell the button what you want it to do.

    Profile photo of guyburns

    Thanks for all the feedback. I had access to the mixer yesterday, and because of the answers here and my prior reading of the PDF and making extensive notes, I mostly had positive results. I have a few more specific questions, but I’ll start a new thread about those.

    Thanks again.

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