Not so much a Kemper issue as a room issue. Can anyone recommend an engineer in West Midlands area?

    I'm loving my Kemper tone but I'm having issues on mixes due to my room.


    I've put quite a bit of effort into my room treatment (rockwool) traps and whilst it has cured quite a few things I have a room mode which is simply beyond my understanding and needs someone with more knowledge of the subject to come to my rescue.


    I'm in Sutton Coldfield near Birmingham so was wondering if anyone knows of a Acoustic engineer in the West Midlands area they could recommend? My Googling hasn't really helped me with most hits being in relation to industrial sound design and noise dissipation. This is a 10' by 14' room so there's a limit to what I can achieve in that small space and what I could justify in spending. If there should happen to be any passers by who have a interest in this particular area the problem is a whacking great null (according to Room Eq Wizard) in the 70 Hz area which is making the bottom end quite impossible to mix. If any specifics are needed I'd be happy to post again but I am conscious that this remains after all a Kemper forum.

    Anything below 100Hz requires serious bass-trapping, and in a room the size of yours, I think you won't get the results you're looking for. Personally, I'd be looking at using smaller monitors with less bass, as illogical as that sounds. Mixing at lower volume might help a bit, too. Basically, anything that lessens the tendency to excite that nasty room mode.


    I suggest posting in the DIY forum at soundonsound.com , you'll get more hits there and there'll be a greater chance of more in-depth, specialist advice. There are also quite a few threads quite similar to yours, so you might also pick up a few tips.


    Cheers,
    Sam

    I'm not sure of the value if this in isolation but here goes.


    This is both monitors on. The left and right in isolation exhibit a very similar null around this mark and a corresponding decay issues in the 30hz region which is of course half the wavelength of my problem mode.


    I suspect its going to be trying to break up some of the reinforced modes at the 30hz which will help in the 60hz region but I dont know how I will achieve that.


    monitors are shooting down the long wall equidistant from side walls. I have moved desk http://www.thomann.de/gb/zaor_miza_x_black_cherry.htm upto 18" forward and back and im currently 2 feet from back wall.


    with corner superchunks, clouds and side wall traps theres about 40 4'by2' RW5 slabs in here none of which will of course treat anything like 30Hz or even 60hz for that matter. I do think I need some one in to see what is salvagable one the correct monitor position is located.


    Anyways heres the screeshot REW5 Watefall

    In that sized room it will be difficult to control those lower frequencies. The more mass you can get into the room corners the better. I have a similar room and similar problem in that two of the corners need to be accessible due to doorways. A good starting point, if you haven't already tried it: aim for a listening position about 30% down the length of the longer side of the room, make the distance between the monitors and your listening position equidistant, also make that distance as small as possible, make xure you have some absorption on all the first refletion points.


    If this doesn't improve the issue you might give room correction software, like IK Multimedia ARC a go. I don't think that will be silver bullet, but it might help.

    Sorry, can't see the waterfall plot; says I don't have access to the folder.


    With regards to size, there's no set law that you will have your particular problem; acoustics is an unpredictable beast.


    Room correction software generally won't fix a null.


    Seems like you've already tried moving the listening position forward and back; good call. I found this to have an even greater effect than my (admittedly limited) bass trapping/broadband absorption. Have you tried moving the monitors back and forth, wide and narrow? Maybe even up and down? Just to see if that makes any difference?



    Just looked at the link for the desk, that's one huge piece of hardware :) I see it invites putting the monitors directly onto it. Monitor placement might not be ideal at that position (nothing to say it isn't, but it might make a difference). Try scooting your chair a bit back and forth to see if that makes a difference.


    You measure down to 30 Hz, I'm guessing you have a sub? If so, try moving it around and/or switching the polarity on it, if it possible.


    How thick are those RW slabs, 4 inches?


    They WILL treat low low frequencies, but will not be very effective in doing so. Proper placement is important. Be aware that treating the main (wall/wall) corners are not always the way to fix specific problems. I found for my problems there are specific spots along a wall/floor corner that will yield a greater effect on some problem areas in my room. Try playing a 30 or 60 sine wave and crawl around on the floor to listen for nulls and peaks. Try putting some of the slabs there, straddling the corner. Do the same along the wall/ceiling corners.

    Generally, the appropriateness of a sub is defined by the room; you need a room big enough to be able to control the standing waves properly, otherwise a sub will do more harm than good and you'll end up chasing your tail when mixing. This is why I suggested trying moving to smaller, less bass-centric speakers. Decent headphones as a second reference tend to be cheaper than the amount of acoustic treatment otherwise required, but if it's a road you're wiling to go down, you could do worse than look at something like this, a specifically-tuned bass trap for the problem frequencies/harmonics.


    Cheers,
    Sam

    Foam is useless at anything under midrange frequencies, unfortunately (despite what the manufacturers want you to believe...). Superchunks (i.e. triangular traps straddling corners from wall to ceiling) are a big step in the right direction for taming standing waves, but with a problem like the OP has, more specialist methods will be required. Investigating adjusting the positioning can be a help if you can manage to sit yourself between the major troughs and resonant peaks. There are a few online room calculators that can help you with finding the approximate positions of problem frequencies (although only on a 2D plane). GIK's website (no, I'm NOT affiliated with them!!!) has a lot of resources and links for this kind of thing.


    Cheers,
    Sam

    Re. Sub: Makes sense, Sam. Even so, I have a question you might be able to answer :) IF the choice was between large monitors or smaller monitors but with a sub, what would you advise? I'd tend toward believing that the latter would be the better choice due to the ability to move that around independently of the monitors and being able to switch the polarity. Ignoring the potential problems of the room size, would this assessment be correct?



    Room mode calculator showing 3d image of the individual modes (i.e. high pressure vs high velocity): http://www.hunecke.de/en/calculators/room-eigenmodes.html

    I guess I'd choose the sub and satellites option, only because then you have more control over the bass frequencies without resorting to EQ (which shifts phase in non-linear incarnations , but can cause other problems in linear phase incarnations). Anything that goes deep though, has the potential to excite nasty room modes and standing waves. It's always a compromise, unless either you're extremely lucky, or you had your (spacious) control room designed by an acoustician! The trick is knowing your room well enough to mix yourself out of problems.


    Cheers,
    Sam

    Quote from sambrox

    I guess I'd choose the sub and satellites option, only because then you have more control over the bass frequencies without resorting to EQ (which shifts phase in non-linear incarnations , but can cause other problems in linear phase incarnations). Anything that goes deep though, has the potential to excite nasty room modes and standing waves. It's always a compromise, unless either you're extremely lucky, or you had your (spacious) control room designed by an acoustician! The trick is knowing your room well enough to mix yourself out of problems.


    Cheers,
    Sam


    Yes! And check the mix on headphones / in another room. And scoot your chair back a foot or two every once in a while to verify that nothing is sticking out or missing...